CN118449285B - Gravity energy storage device utilizing topography height difference and power generation system - Google Patents

Abstract

The present disclosure provides a gravity energy storage device and a power generation system that utilizes terrain height differences, wherein the gravity energy storage device includes a sub-control system and multiple energy storage working units connected thereto, and the energy storage working units include slideways and gravity energy storage equipment. The power generation system includes a total control system and at least one wind power or photovoltaic power plant that supplies power to the main power grid through the gravity energy storage device. The present disclosure makes full use of terrain height differences to construct a gravity energy storage device, and multiple gravity energy storage devices correspond to one wind power or photovoltaic power plant, which can achieve large-capacity and multiple modes of energy storage and release. The gravity energy storage device can not only ensure that the wind power plant can generate electricity steadily under conditions of light wind and constantly changing wind speed, or the photovoltaic power plant can generate electricity steadily under conditions of low-intensity light or constantly changing light intensity, but also meet the main power grid's requirements for the gravity energy storage device to release electricity in a constantly changing manner.

Description

A gravity energy storage device and power generation system utilizing terrain height difference

Technical Field

The present invention belongs to the technical field of wind power generation and kinetic energy storage, and in particular relates to a gravity energy storage device and a power generation system utilizing terrain height differences.

Background Art

Wind and solar energy are both renewable energy sources. Since they come from nature, they will not be exhausted. This characteristic makes wind power generation and photovoltaic power generation a good choice for sustainable power supply. Compared with fossil fuel power generation, wind power generation and photovoltaic power generation can significantly reduce the emission of carbon dioxide and other greenhouse gases, which helps to mitigate the impact of global warming. However, affected by natural and technical factors, wind power generation and photovoltaic power generation are intermittent, random, and poorly dispatchable, which will cause a series of power quality problems. First, when wind power generation and photovoltaic power generation are affected by weather and the output power fluctuates, it will cause voltage fluctuations on the wind farm transmission line, and then cause grid voltage fluctuations; when the output power of the wind power generation system is large, flicker will also occur. Secondly, since the output of wind power generation and photovoltaic power generation is somewhat random, as the proportion of these two new energy sources in the total power generation of the power grid continues to increase, there may be frequency fluctuations in the power grid, which will have a bad impact on the power system and its users. In addition, since wind power generation and photovoltaic power generation both use a large number of power electronic equipment, they will generate a large number of harmonics and DC components. After harmonics are injected into the power system, they will cause voltage distortion in the power grid system and affect the power quality of the entire power grid system. When the proportion of these two new energy sources is not large, the above defects can be controlled within the range allowed by the power grid through modern power electronics technology; when these two new energy sources are connected to the grid on a large scale, it will have a great impact on the power system. The power grid must control the access to the two new energy generation capacity within a controllable range to minimize the adverse effects. This not only greatly limits the construction scale and development speed of these two new energy sources, but also leads to coal-fired power plants that are more environmentally damaging and have a higher proportion of carbon emissions as the main power generation. In order to ensure the smooth operation of the power grid, part of the power generation capacity of these two new energy sources is often abandoned in vain, so that the new energy power generation system cannot obtain the expected economic benefits. To this end, measures have been taken to develop and promote new energy storage technologies and supporting new energy storage power stations to reduce energy waste and improve the utilization efficiency of new energy, thereby achieving energy conservation and environmental protection. Secondly, new energy storage technologies can improve the reliability and stability of energy. Since the energy storage power station adopting new energy storage technology requires a large amount of capital investment, it currently plays three main roles: first, balancing the supply and demand of electricity. The energy storage power station can store electricity during peak electricity demand to balance the power supply and ensure the stability of the power network, which helps to reduce the risk of power outages and improve the reliability of the power system; second, integrating renewable energy: renewable energy such as wind and solar energy are volatile, and energy storage power stations can capture and store excess electricity to provide electricity during unstable periods; third, frequency regulation and backup power supply. Energy storage power stations can be used as frequency regulation equipment for power systems to quickly respond to fluctuations in electricity demand. However, this cannot completely eliminate the above-mentioned adverse effects of these two types of new energy generation on the power grid. For the stability of the entire power grid and higher power quality, new energy can only occupy a small share in the power supply, and the traditional power generation method based on coal-fired power generation is still the main means of power generation because the power generation process is fully controllable and the power quality is excellent. This is contrary to the original intention of vigorously developing new energy.

Gravity energy storage devices use electric motors to do work when there is surplus electricity, lift heavy objects to a high place, and convert electrical energy into gravitational potential energy; when electricity is needed, heavy objects are used to do work to drive the generator to rotate, thereby converting gravitational potential energy into electrical energy. Gravity energy storage devices have the advantages of safety, fast response, large energy storage capacity, and long life. In order to generate electricity for a long time, a common method is to build a high-height (generally about 120m) energy storage tower or metal structure frame on the ground, lower the heavy blocks stored at a high place one by one, and use the gravity of the heavy blocks to drive the generator to rotate and generate electricity, thereby converting gravitational potential energy into electrical energy. This method requires continuous acquisition and release of heavy objects, high movement accuracy requirements, and certain uncertainties; after the heavy objects are released to high or low floors, they need to be reasonably arranged and placed to accommodate more heavy objects and maximize energy storage or release, which places extremely high demands on the operation of computers and software; in addition, the construction of high-height energy storage towers or metal structure frames is labor-intensive, time-consuming, and costly.

In order to achieve the reuse of resources, there are gravity energy storage devices built using abandoned oil and gas wells, water towers or mines. There are also gravity energy storage devices that use the height difference of mountains to move heavy objects. However, these devices have low energy density and cannot absorb all the electricity generated by local renewable energy. They cannot even store excess electricity from renewable energy, resulting in the fact that such gravity energy storage devices are not widely used.

Summary of the invention

The present disclosure aims to solve one of the technical problems in the related art at least to some extent.

To this end, the present disclosure provides a gravity energy storage device that utilizes terrain height differences and a power generation system having the gravity energy storage device. The present disclosure utilizes a slide group set up by terrain height differences, and constructs a gravity energy storage device by adding energy storage equipment, so as to achieve large-capacity and multiple ways of energy storage and release. The present disclosure connects the gravity energy storage device between the existing wind power or photovoltaic power generation system and the power grid, so that the electric energy generated by the above two new energy sources is not directly input into the main power grid, but is stored by the above gravity energy storage device; when the main power grid needs electric energy, the energy is released by the above gravity energy storage device, and the energy release process of the above gravity energy storage device is controllable throughout, which completely eliminates the technical problems caused by the instability of power generation of the two new energy sources. At the same time, it creates conditions for some regions to establish a power supply pattern dominated by new energy and explore the gradual withdrawal of coal-fired power plants from the power system.

In order to achieve the above objectives, the present disclosure adopts the following technical solutions:

A first aspect of the present disclosure provides a gravity energy storage device utilizing terrain height difference, comprising a sub-control system and a plurality of energy storage working units, each energy storage working unit being connected to the sub-control system via a control cable;

The energy storage working unit comprises a slideway arranged by utilizing the height difference of the terrain and a gravity energy storage device matched with the slideway, wherein the gravity energy storage device comprises a flexible weight, a drag mechanism, a first transmission and a generator motor connected in sequence, wherein the generator motor is connected to the power cable of the wind power or photovoltaic power generation system through a power cable, and the height of the flexible weight in the slideway is changed by the drag mechanism to realize energy storage and energy release; the drag mechanism comprises a fixed pulley, a drum and a drum brake, one end of the flexible weight is located in the slideway, and the other end bypasses the fixed pulley located above the top of the slideway and is wound on a drum located on one side of the top of the slideway, the drum is sleeved on a drum shaft, one end of the drum shaft is connected to the low-speed shaft of the first transmission, the high-speed shaft of the first transmission is connected to the generator motor, a switch is provided on the power cable, and the drum brake, the switch and the generator motor are connected to the sub-control system through the control cable;

The sub-control system is used to open or close a corresponding number of the energy storage working units according to the energy storage or release capacity requirements of the overall control system of the wind power or photovoltaic power generation system, control and monitor the equipment status in each energy storage working unit, transmit the status and parameters of the gravity energy storage device to the overall control system, and re-regulate the gravity energy storage device according to the instructions issued by the overall control system.

In some embodiments, the slide is installed on the ground, a hillside or a building with a height difference of at least 50 meters. At least three slides are provided in the gravity energy storage device. A drainage outlet is provided at the bottom of the slide. The angle between the slide and the horizontal plane is not less than 35 degrees. There are no zigzag turns in the slide, and each turn has a curvature radius of more than 10 meters.

In some embodiments, the flexible weight is made of a flexible material with a mass of more than 5,000 kg and an average density of more than 3,000 kg/cubic meter. A safety distance should be reserved between the lowest position and the highest position of one end of the flexible weight in the slide and the two ends of the slide.

In some embodiments, a load stabilizer is provided at the other end of the drum shaft, and the load stabilizer eliminates the influence of the gravity change of the flexible weight in the slideway on the torque of the drum and the generator motor by absorbing and releasing elastic potential energy.

In some embodiments, the load stabilizer includes an elastic element and a second transmission. The other end of the reel shaft is connected to the high-speed shaft of the second transmission, and is transmitted to the elastic element after being decelerated by the second transmission. The elastic element gradually changes the torque on the reel and the generator motor in a linear manner, thereby keeping the torque acting on the reel and the generator motor constant.

In some embodiments, the elastic element is a coil spring with linear characteristics, and the second transmission is a planetary transmission.

In some embodiments, the sub-control system includes a first operation controller and a sensor unit connected thereto, a first grid-connected control unit, a first safety protection unit, a first monitoring unit, a first communication interface circuit and a first user interface; the sensor unit includes an infrared sensor for detecting whether one end of the flexible weight is located in the slide at the lowest position and the highest position in the slide, a speed sensor for detecting the speed of the generator motor and a code disc sensor for detecting the number of rotations of the drum. When the speed of the generator motor detected by the speed sensor exceeds the set speed range, the first operation controller controls the excitation current and voltage of the generator motor so that the speed of the generator motor runs within the set speed range. The first operation controller senses the real-time energy storage and energy release margin of the energy storage working unit according to the number of rotations of the drum detected by the code disc sensor; the first The grid-connected control unit is used to connect the electric energy generated by the gravity energy storage device to the main power grid; the first safety protection unit is used to deal with emergencies. When the parameters exceed the preset working range, the problematic energy storage working unit or even the entire gravity energy storage device is shut down in time; the first monitoring unit is used to monitor the working status of the energy storage working unit in real time, and transmit the data to the first operation control unit, the first safety protection unit and the first user interface; the first communication interface circuit is used to realize data communication during the operation of the gravity energy storage device; the first user interface is used to input user instructions, change parameters, and display the operating status, data and fault conditions of the gravity energy storage device; the first operation controller is used for operation monitoring of the gravity energy storage device, including start and stop control, control of various electronic devices and power grid monitoring.

In some embodiments, the sub-control system controls the working mode of each energy storage working unit according to the energy storage and release instructions of the overall control system of the wind or photovoltaic power generation system: when the wind farm or photovoltaic power generation site generates less power, the overall control system instructs the sub-control system of the gravity energy storage device to start a single or multiple energy storage working units to participate in energy storage; when the wind farm or photovoltaic power generation site generates power close to full load, the overall control system instructs the sub-control system to start all energy storage working units to participate in energy storage at the same time; when the wind farm or photovoltaic power generation site generates more power gradually, the overall control system instructs the sub-control system to start a single or multiple energy storage working units to successively participate in energy storage.

In some embodiments, the operation process of the gravity energy storage device includes:

During energy storage operation: the sub-control system opens the gravity energy storage devices of the corresponding number of energy storage working units according to the energy storage capacity requirements of the total control system. In the gravity energy storage devices of the opened energy storage working units, the sub-control system first starts the traction mechanism, and then connects the power cable to start the generator motor, and uses the traction mechanism to lift one end of the flexible weight that is in the slide and has not reached the highest position in the slide; when the flexible weight reaches the highest position in the adjacent slide, the sub-control system first disconnects the power cable, brakes the generator motor to reduce its rotation speed, and then controls the traction mechanism to reduce the lifting speed of the flexible weight; when one end of the flexible weight reaches the highest position in the slide, the sub-control system controls the traction mechanism to keep one end of the flexible weight stationary, thereby realizing the conversion of excess electrical energy into the gravity of the flexible weight. potential energy, and store it; if there is still surplus electric energy to be stored, the sub-control system will continue to open the gravity energy storage equipment of the remaining energy storage working units until the entire gravity energy storage device lifts one end of the flexible weights in all energy storage working units to the highest position in the slideway, achieving full-load energy storage, and the energy storage operation is completed; when a single or part of the energy storage working units are in the energy storage process and there is an unexpected lack of energy storage capacity, the sub-control system disconnects the power cable, brakes the generator motor to reduce its speed, and then controls the towing mechanism to stop one end of the flexible weight at the current position in the slideway, and the energy storage operation is suspended. If there is a subsequent energy storage requirement, the energy storage working unit whose energy storage operation is suspended will continue the energy storage operation until one end of the flexible weight reaches the highest position in the slideway, achieving full-load energy storage of the energy storage working unit, and finally achieving full-load energy storage of the gravity energy storage device;

During the energy release operation: the sub-control system opens the corresponding number of gravity energy storage devices of the energy storage working units according to the required energy release capacity. In the gravity energy storage devices of the opened energy storage working units, the sub-control system first connects the power cable to start the generator motor, and then controls the dragging mechanism to release the flexible weight so that one end of the flexible weight continues to descend in the slide; when one end of the flexible weight reaches the lowest position in the adjacent slide, the sub-control system disconnects the power cable, brakes the generator motor to reduce its rotation speed, and then controls the dragging mechanism to reduce the descending speed of the flexible weight; when one end of the flexible weight reaches the lowest position in the slide, the sub-control system controls the dragging mechanism to keep one end of the flexible weight stationary, thereby realizing the conversion of the gravitational potential energy of the flexible weight into electrical energy; if the If the gravity energy storage device still has energy release requirements, the control system will open the gravity energy storage devices of the remaining corresponding number of energy storage working units until the entire gravity energy storage device lowers one end of the flexible weights in all the energy storage working units to the lowest position in the slideway to achieve full-load energy release; when a single or part of the energy storage working units are in the process of releasing energy and unexpectedly no energy release is required, the sub-control system will first disconnect the power cable and brake the generator motor to reduce its speed, and then control the towing mechanism to stop one end of the flexible weight at the current position in the slideway, and the energy release operation will be suspended. If there is a subsequent energy release requirement, the energy storage working unit whose energy release operation has been suspended will continue the energy release operation until one end of the flexible weight reaches the lowest position in the slideway, achieving full-load energy release of the energy storage working unit, and finally achieving full-load energy release of the gravity energy storage device.

A second aspect of the present disclosure provides a power generation system, which is a wind power or photovoltaic power generation system, comprising a general control system and at least one wind power or photovoltaic power plant that supplies power to a main power grid through a gravity energy storage device, wherein the gravity energy storage device adopts the gravity energy storage device according to any embodiment of the first aspect of the present disclosure, and a boost control device is further connected between the gravity energy storage device and the main power grid; each wind power or photovoltaic power plant is equipped with at least three gravity energy storage devices, and the maximum rated power generation power of the wind power or photovoltaic power plant is equal to the energy storage power of one gravity energy storage device. When the wind power or photovoltaic power plant generates electricity, one gravity energy storage device performs energy storage operation, one gravity energy storage device performs energy release operation, and at least one gravity energy storage device is in a full-load energy storage state; the wind power or photovoltaic power plant, the boost control device and the sub-control systems in each gravity energy storage device are all connected to the general control system through control cables, and power is transmitted between the wind power or photovoltaic power plant, the gravity energy storage device and the main power grid through power cables;

The overall control system is used to open and close the corresponding gravity energy storage device to store energy and output electric energy to the main power grid according to the power generation and operating conditions of the wind or photovoltaic power plant, and monitor the operating conditions of the power generation system.

In some embodiments, the overall control system includes a second operation controller and a second grid-connected control unit, a second safety protection unit, a second monitoring unit, a second communication interface circuit and a second user interface connected thereto; the second grid-connected control unit is used to connect the electric energy generated by the gravity energy storage device to the main power grid; the second safety protection unit is used to deal with emergencies, and when the parameters exceed the preset working range, the problematic energy storage working unit or even the entire gravity energy storage device is shut down in time; the second monitoring unit is used to monitor the working status of the energy storage working unit in real time and transmit the data to the second operation control unit, the second safety protection unit and the second user interface; the second communication interface circuit is used to realize data communication between the overall control system and the control system of the wind or photovoltaic power plant, the sub-control system and the boost control device; the second user interface is used to input user instructions, change parameters, and display the operating status, data and fault conditions of the gravity energy storage device; the second operation controller is used for operation monitoring of the power generation system, including start and stop control, control of various electronic devices and power grid monitoring.

In some embodiments, the operation process of the power generation system includes:

During energy storage operation: the control system of the wind power or photovoltaic power plant sends the value of the wind power or photovoltaic power generation capacity and the power generation scale in the future to the general control system in real time, and the general control system sends an energy storage operation instruction to a gravity energy storage device that is not at full load energy storage, and the sub-control system of the gravity energy storage device starts the corresponding number of energy storage working units in the gravity energy storage device. At the same time, the general control system sends an instruction to the control system of the wind power or photovoltaic power plant, connects the power cable between the wind power or photovoltaic power plant and the gravity energy storage device, and the gravity energy storage device that receives the energy storage operation instruction starts to store energy. During the energy storage operation, the general control system obtains various data of the gravity energy storage device and the wind power or photovoltaic power plant in real time and sends control instructions. When the gravity energy storage device that performs the energy storage operation When the energy storage device reaches full load energy storage, the general control system sends an instruction to the sub-control system to end the current energy storage operation of the gravity energy storage device, and sends an energy storage operation instruction again to a gravity energy storage device that has already released energy, and the gravity energy storage device that receives the energy storage operation instruction starts the corresponding number of energy storage working units in the gravity energy storage device through the sub-control system; when the power generation value of the wind power or photovoltaic power plant cannot meet the starting power of any energy storage working unit in the gravity energy storage device, the general control system sends an instruction to the control system of the wind power or photovoltaic power plant to cut off the power cable between the wind power or photovoltaic power plant and the gravity energy storage device, and at the same time, the general control system sends an instruction to the sub-control system of the gravity energy storage device that is performing energy storage operation to shut down the energy storage working unit that is performing energy storage operation;

During energy release operation: the general control system preferentially sends the energy release demand instruction of the main power grid to a gravity energy storage device that has stored energy at full load, and the gravity energy storage device starts the energy release operation, and its sub-control system activates the corresponding energy storage working unit to start the energy release operation. During the energy release operation, the general control system obtains various data of the gravity energy storage device and the wind or photovoltaic power plant in real time and issues control instructions. When the gravity energy storage device finishes releasing energy, the general control system sends the current energy release demand instruction of the main power grid to another gravity energy storage device that has stored energy at full load, and the power generation system continues to emit electric energy until all gravity energy storage devices in the power generation system can no longer meet the power supply demand of the main power grid. The general control system controls the boost control device to disconnect the power cable between the gravity energy storage device and the main power grid.

The present disclosure has the following characteristics and beneficial effects:

The present invention utilizes a group of slideways set up due to terrain height differences, and constructs a gravity energy storage device by adding energy storage equipment. Multiple gravity energy storage devices correspond to one wind or photovoltaic power plant, which can achieve large-capacity and multiple modes of energy storage and release. Specifically, the energy storage capacity of each gravity energy storage device can store the electric energy generated by the corresponding wind farm or photovoltaic power plant at full load within a certain period of time. During the period when the output of the wind farm or photovoltaic power plant decreases or there is no output at all due to natural reasons, multiple gravity energy storage devices will continue to generate electricity. In each gravity energy storage device, a single or multiple slides can participate in energy storage or release at the same time, all slides can participate in energy storage or release at the same time, a single slide can participate in energy storage or release in succession, and some slide groups can participate in energy storage or release as a whole. This can not only ensure that the wind farm can generate electricity steadily under the conditions of light wind and constantly changing wind speed, or the photovoltaic power plant can generate electricity steadily under the conditions of low-intensity light or constantly changing light intensity, but also meet the main power grid's requirements for the gravity energy storage device to release electricity in a constantly changing manner. More importantly, wind farms or photovoltaic power plants do not supply electricity directly to the main power grid, but instead generate electricity and connect to the grid through gravity energy storage devices. The electricity generated by the gravity energy storage devices remains constant, thereby eliminating the adverse effects of wind or solar power generation on the main power grid and creating conditions for increasing the proportion of the above two types of renewable energy power generation in the regional power grid.

In addition, the use of flexible weights can adapt well to different occasions with terrain differences. When the slide is arranged along the ground, hillside or building with terrain differences, the flexible weights can pass through any channel except for zigzag turns. As long as the entire slide is designed without any zigzag turns and all turns have a certain curvature radius, the flexible weights can pass through.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the layout of a gravity energy storage device utilizing terrain height differences provided by an embodiment of the first aspect of the present disclosure;

FIG2 is a side view of a single energy storage working unit in the gravity energy storage device shown in FIG1 ;

FIG3 is a top view of a single energy storage working unit in the gravity energy storage device shown in FIG1 ;

4 is a schematic diagram of a flexible weight in a single energy storage working unit in the gravity energy storage device shown in FIG. 1 reaching an upper predetermined position of the slide and a lower predetermined position of the slide in the slide;

FIG5 is a schematic diagram of the structure of a sub-control system in the gravity energy storage device shown in FIG1;

FIG6 is a schematic side view of the internal structure of the load stabilizer in the gravity energy storage unit shown in FIG2;

FIG7 is a schematic top view of the internal structure of the load stabilizer in the gravity energy storage unit shown in FIG2;

FIG8 is a schematic structural diagram of a power generation system having the gravity energy storage device according to an embodiment of the second aspect of the present disclosure.

Reference numerals:

100-energy storage working unit, 110-slideway, 120-gravity energy storage device, 121-flexible weight, 122-dragging mechanism, 1222-fixed pulley, 1223-reel, 1224-reel brake, 123-generator motor, 124-first transmission, 125-load stabilizer, 1251-elastic element, 1252-second transmission, 126-power cable, 127-switch;

200-control cable;

300-sub-control system, 310-sensing unit, 311-infrared sensor, 312-speed sensor, 313-code disc sensor, 3131-code disc, 3132-signal transmitter and receiver, 320-operation controller, 330-grid-connected control unit, 340-safety protection unit, 350-monitoring unit, 360-communication interface circuit, 370-user interface;

400-power generation system, 410-wind farm, 411-wind turbine generator set, 412-wind farm power collection system, 413-wind farm control system, 420-gravity energy storage device, 430-general control system, 440-power cable, 450-boost control device;

500- Main grid.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

On the contrary, the present application covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present application as defined by the claims. Further, in order to make the public have a better understanding of the present application, some specific details are described in detail in the detailed description of the present application below. Those skilled in the art can fully understand the present application without the description of these details.

In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the basis or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

In the description of the present disclosure, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

In the present disclosure, unless otherwise expressly specified and limited, a first feature being “above” or “below” a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being “above”, “above”, and “above” a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

1 to 4 , a gravity energy storage device using terrain height difference is provided in a first aspect of the present disclosure, comprising: a plurality of energy storage working units 100 and a sub-control system 300 , wherein each energy storage working unit 100 is connected to the sub-control system 300 via a control cable 200 ;

The energy storage working unit 100 includes a slideway 110 and a gravity energy storage device 120. The gravity energy storage device 120 includes a flexible weight 121, a drag mechanism 122, a first transmission 124 and a generator motor 123 connected in sequence. The generator motor 123 is connected to the power cable of the wind power or photovoltaic power generation system through a power cable 126, and the height of the flexible weight 121 in the slideway 110 is changed by the drag mechanism 122 to realize energy storage and energy release;

The sub-control system 300 is used to open or close a corresponding number of the energy storage working units according to the energy storage or release capacity requirements of the overall control system of the wind power or photovoltaic power generation system, control and monitor the equipment status in each energy storage working unit, transmit the status and parameters of the gravity energy storage device to the overall control system, and adjust the gravity energy storage device again according to the instructions issued by the overall control system.

Furthermore, the sub-control system 300 controls the working mode of each energy storage working unit 100 according to the energy storage and release instructions of the overall control system of the wind power or photovoltaic power generation system: when the wind power plant or photovoltaic power generation site generates less power, the overall control system of the power generation system instructs the sub-control system 300 of the gravity energy storage device to start a single or multiple energy storage working units 100 to participate in energy storage; when the power generation of the wind power plant or photovoltaic power generation site is close to full load, the overall control system 430 instructs the sub-control system 300 to start all energy storage working units 100 to participate in energy storage at the same time; when the power generation of the wind power plant or photovoltaic power generation site gradually increases, the overall control system instructs the sub-control system 300 to start a single or multiple energy storage working units 100 to successively participate in energy storage.

In some embodiments, the number of energy storage working units 100 can be 3 or more, or even hundreds, so as to make use of the terrain height difference and greatly save construction costs.

In some embodiments, each energy storage unit 100 has the same structure, and each includes a slide 110 set up using the height difference of the terrain and a gravity energy storage device 120. The slide 110 is laid along the ground, hillside or built building with a height difference, and the height difference between the upper and lower ends of the slide 110 is more than 50 meters. The angle between the slide 110 and the horizontal plane is not less than 35 degrees. The entire slide 110 does not have any broken line turns. All turns have a curvature radius of more than 10 meters, and a drain is provided at the bottom of the slide 110. The gravity energy storage device 120 includes a flexible weight 121, a traction mechanism 122 and a generator motor 123 connected in sequence. The flexible weight 121 is dragged into the slide 110 by the dragging mechanism 122. The flexible weight 121 can be made of a flexible material with a mass of more than 5,000 kg and an average density of more than 3,000 kg/m3, such as a steel wire rope. In addition, when the flexible weight 121 is wound on the dragging mechanism 122, it has a circular cross-section, is straight when suspended, and can be placed in any curved shape when in a free state. One end of the flexible weight 121 is a free end. A safety distance should be reserved between the free end at the lowest position and the highest position in the slide 110 and the bottom and top of the slide 110, respectively, to avoid the free end of the flexible weight 121 from damaging the slide 110 when it descends to the lowest position and to avoid damage to the facilities outside the slide 110 when the flexible weight 121 is lifted to the highest position. The other end of the flexible weight 121 is fixed to the dragging mechanism 122. The dragging mechanism 122 includes a fixed pulley 1222, a drum 1223 and a drum brake 1224. One end of the flexible weight 121 is located in the slide 110, and the other end is wound around the fixed pulley 1222 located on the top of the slide 110 and is wound on the drum 1223 located on one side of the top of the slide 110. When one end of the flexible weight 121 is located at the highest position in the slide 110, the cross-sectional diameter of the flexible weight 121 wound on the drum 1223 is 120mm~200mm, and the diameter of the drum 1223 is generally 6m~10m. At least one circle of the flexible weight 121 should be wound around the drum 1223. Therefore, the length of the flexible weight 121 when unfolded can reach 300m~2000m, and its stiffness is still considered to change linearly when the flexible weight 121 is rolled up or unfolded. The support shaft of the fixed pulley 1222 is connected to the foundation, and the drum 1223 is sleeved on the drum shaft. One end of the drum shaft is connected to the low-speed shaft of the first transmission 124, and the high-speed shaft of the first transmission 124 is connected to the generator motor 123. The generator motor 123 is connected to the power cable of the power generation system through a power cable 126 provided with a switch 127; the generator motor 123 is connected to the power cable of the power generation system through a power cable 126 provided with a switch 127, and the sub-control system 300 controls the opening and closing of the switch 127 on the power cable 126, and controls the connection of the excitation winding current and voltage in the generator motor 123 and the start and stop of the electromagnetic brake device. The first transmission 124 can be a planetary transmission or other types of transmissions.

In some embodiments, referring to FIG. 4 and FIG. 5, the sub-control system 300 includes a plurality of sensor units 310, an operation controller 320, a grid-connected control unit 330, a safety protection unit 340, a monitoring unit 350, a communication interface circuit 360 and a user interface 370. Among them, each sensor unit 310 is respectively arranged in a corresponding energy storage working unit 100, and each includes two infrared sensors 311, a speed sensor 312 and a code disc sensor 313; the two infrared sensors 311 are respectively arranged on the slideway 110 at the lowest position and the highest position of the flexible weight 121 in the slideway 110, and are used to measure whether the free end of the flexible weight 121 is close to the upper and lower limit positions in the slideway 110; the speed sensor 312 is connected to the generator motor 123, and is used to measure the speed of the generator motor 123. When the speed of the generator motor 123 detected by the speed sensor 312 exceeds the set speed range, the operation controller 320 controls the excitation current voltage of the generator motor 123, so that the generator motor 1 The speed of the reel 1223 is within the set speed range; the code disc sensor 313 is used to measure the number of turns of the reel 1223. Since the stiffness of the flexible weight 121 when being rolled up or released can be regarded as a linear change, the real-time energy storage and release margin of the energy storage working unit 100 to which the reel 1223 belongs can be sensed by detecting the number of turns of the reel 1223. The code disc sensor 313 includes a code disc 3131 fixedly sleeved on the reel shaft as a rotor and a signal transmitter receiver 3132 as a stator. During the reel rotation process, the code disc 3131 rotates synchronously with the reel coaxially. The number of turns of the code disc 3131 collected by the signal transmitter receiver 3132 is the number of turns of the reel 1223. The sensor unit 310 sends the collected data to the operation controller 320. The grid-connected control unit 330 is used to connect the electric energy generated by the gravity energy storage device to the main power grid 500. The safety protection unit 340 is used to deal with emergencies. When the parameters exceed the preset working range, the energy storage working unit 100 with problems is shut down in time, or even the entire gravity energy storage device. The monitoring unit 350 is used to monitor the working status of the gravity energy storage device 120 and the energy storage working unit 100 in real time, and transmit the data to the operation control unit 320, the safety protection unit 340 and the user interface 370. The communication interface circuit 360 is used for data communication during the operation of the gravity energy storage device of this embodiment, including but not limited to data communication between the sub-control system 300 and the general control system 430, and data communication between the first operation controller and the sensor unit 310, the drum brake 1224, the switch 127 and the generator motor 123. The user interface 370 is used to input user instructions, change parameters, and display the operating status, data and faults of the gravity energy storage device; the human-computer interaction and display functions of the user interface 370 are realized through the computer user display system and the real-time tracing system. The operation controller 320 is the center of the sub-control system 300, and is connected to the sensor 310, the grid-connected control unit 330, the safety protection unit 340, the monitoring unit 350, the communication interface circuit 360 and the user interface 370, and plays the role of operation monitoring, including system start and stop, other functional module control and grid monitoring, etc. The operation controller 320 mainly realizes these functions through a programmable controller. In addition, the operation controller 320 of the sub-control system 300 is connected to various sensors in the energy storage working unit 100 through the control cable 200, and is also connected to the drum brake 1224, the generator motor 123 and the switch 127 to realize the control of the working mode of the energy storage working unit 100 and the monitoring of the working state.

In some embodiments, considering that when the flexible weight 121 descends and the flexible weight 121 located in the slide 110 gradually becomes longer, the gravity of the flexible weight 121 gradually increases, and the torque on the reel 1223 gradually increases, and then the torque on the generator motor 123 also increases continuously, therefore, a load stabilizer 125 is provided at the other end of the reel coaxially, and the load stabilizer 125 eliminates the influence of the gravity change of the flexible weight 121 in the slide 110 on the torque of the generator motor 123 by absorbing and releasing elastic potential energy. Specifically, referring to FIGS. 6 and 7 , the load stabilizer 125 includes an elastic element 1251 and a second transmission 1252. The other end of the shaft of the drum 1223 is connected to the high-speed shaft of the second transmission 1252, and the second transmission 1252 decelerates the shaft and transmits the shaft to the elastic element 1251. The elastic element 1251 gradually reduces the torque on the drum 1223 in a linear manner, thereby keeping the torque acting on the drum 1223 constant, and also keeping the torque acting on the generator motor 123 constant. Similarly, when the flexible weight 121 rises and moves, the load stabilizer 125 includes an elastic element 1251 and a second transmission 1252. The flexible weight 121 in the slideway 110 gradually becomes shorter, the gravity of the flexible weight 121 gradually decreases, and the torque acting on the reel 1223 tends to gradually decrease. The other end of the reel 1223 shaft is connected to the high-speed shaft of the second transmission 1252, and is transmitted to the elastic element 1251 after being decelerated by the second transmission 1252. The elastic element 1251 gradually increases the torque on the reel 1223 in a linear law, so that the torque acting on the reel 1223 remains constant, and the torque acting on the generator motor 123 remains constant. Optionally, the elastic element 1251 adopts a coil spring with linear characteristics, one end of the coil spring is fixed to the housing, and the other end is fixed to the rotating shaft. The force acting on the rotating shaft F=kx, where k is the elastic coefficient of the coil spring, and x is the deformation of the coil spring. The second transmission 1252 adopts a planetary transmission. The advantage is that the input shaft and the output shaft remain on the same axis and are highly efficient. In addition: when the outer gear ring of the planetary transmission is fixed, the first-stage speed increase ratio of the planetary wheel carrier shaft and the sun wheel shaft can reach 1:7. The coil spring can generally be rotated 30 times from the shaft rotation to the tightening direction, so that the reel can reach 210 rotations through the speed increase ratio. When the diameter of the reel 1223 is 6 meters and the cross-sectional diameter of the flexible weight 121 wrapped around the reel 1223 is 120 mm, the length of the flexible weight 121 unfolded from the reel fully meets the requirements of the number of rotations of the reel 1223 and the unfolding length of the flexible weight 121 when the flexible weight 121 is unfolded.

In some embodiments, the operation process of the gravity energy storage device provided in the first aspect of the present disclosure includes:

During energy storage operation: the sub-control system 300 controls the opening of the corresponding number of gravity energy storage devices 120 of the energy storage working units 100 according to the required energy storage capacity. In the gravity energy storage devices 120 of the opened energy storage working units 100, the operation controller 320 in the sub-control system 300 first controls the drum brake 1224 to release the drum 1223 through the communication interface circuit 360, and then controls the switch 127 on the power cable 126 to turn on, and starts the generator motor 123 to rotate. The generator motor 123 reduces the speed through the first transmission 124 to drive the drum 1223 to rotate. The drum 1223 changes the direction of the flexible weight 121 by winding the flexible weight 121 and lifting the part of the flexible weight 121 in the slideway 110 with the help of the fixed pulley 121. When the infrared sensor 311 in the sensing unit 310 detects that the flexible weight 121 is close to the upper predetermined position of the slide 110, the operation controller 320 in the sub-control system 300 first disconnects the switch 127 on the power cable 126 through the communication interface circuit 360, brakes the generator motor 123 to reduce its rotation speed, and then controls the drum brake 1224 to brake the drum 1223 to reduce its rotation speed, and finally controls the drum brake 1224 to lock the drum 1223, thereby converting electrical energy into the gravitational potential energy of the flexible weight 121. During the energy storage process of the energy storage working unit 100, the torque generated by the flexible weight 121 and the elastic potential energy released by the load stabilizer 125 compensate each other, so that the generator motor 123 is in a stable load state. Energy storage is completed. Specifically: due to the large height difference between the two ends of the slide 110, the gravity of the flexible weight 121 is constantly changing. After the drum 1223 winds up a part of the flexible weight 121 in the slide 110, the gravity of the flexible weight 121 in the slide 110 gradually decreases according to a linear law, and the torque of the gravity of the flexible weight 121 on the drum 1223 also gradually decreases according to a linear law. The load of the generator motor 123 gradually decreases. In order to stabilize the load, the load stabilizer 125 gradually increases the corresponding load at the same time. The load stabilizer 125 adopts the principle of tightening the spring, so the load stabilizer 125 gradually increases the torque on the drum 1223 according to a linear law, so that the torque acting on the drum 1223 remains constant, thereby making the load of the generator motor 123 stable. If there is still surplus electric energy to be stored, the sub-control system 300 activates the gravity energy storage devices 120 of the remaining corresponding number of energy storage working units 100 until the entire gravity energy storage device lifts the flexible weights 121 in all energy storage working units 100 to the upper predetermined position of the slideway 110 to achieve full-load energy storage. When a single or part of the energy storage working units 100 are in the process of energy storage and there is an unexpected situation that there is no energy storage capacity, the sub-control system 300 disconnects the power cable 126, brakes the generator motor 123 to reduce its rotation speed, and then controls the drum brake 1224 to brake the drum 1223 to reduce its rotation speed, and then controls the drum brake 1224 to lock the drum 1223, so that the flexible weight 121 in the slideway 110 stops at the current position, and the energy storage operation is suspended. If there is a subsequent energy storage requirement, the energy storage working unit 100 whose energy storage operation has been suspended can continue the energy storage operation until the flexible weight 121 reaches the predetermined position on the upper part of the slide 110, thereby achieving full-load energy storage of the energy storage working unit 100 and further achieving full-load energy storage of the gravity energy storage device. During the energy storage operation, the speed sensor 312 in the sensor unit 310 in the sub-control system detects the speed of the generator motor 123 at any time. When the speed of the generator motor 123 exceeds the set speed range, the operation controller 320 in the sub-control system 300 controls the excitation current voltage of the generator motor 123 through the communication interface circuit 360 to make the speed of the generator motor 123 return to the set speed range. When the speed of the generator motor 123 cannot return to the set speed range, the safety protection unit 340 shuts down the problematic energy storage working unit 100 through the operation controller 320; during the energy storage operation, the code disk sensor 313 in the sensor unit 310 in the sub-control system 300 detects the number of turns of the reel 1223 at any time. The sub-control system 300 senses the real-time energy storage margin of the energy storage working unit 100 through the communication interface circuit 360, so that the operation controller 320 can start or stop energy storage for the energy storage working unit 100.

During the energy release operation: the sub-control system 300 opens the gravity energy storage devices 120 of the corresponding number of energy storage working units 100 according to the required energy release capacity. In the gravity energy storage devices 120 of the opened energy storage workstation 100, the operation controller 320 in the sub-control system 300 first controls the switch 127 on the power cable 126 through the communication interface circuit 360, and then turns on the generator motor 123, and then controls the drum brake 1224 to release the drum 1223. The flexible weight 121 changes direction with the help of the fixed pulley 1222 and pulls the drum 1223 on the ground to rotate. The drum 1223 increases the speed through the first transmission 124 and drives the generator motor 123 to generate electricity. During the rotation of the drum 1223, the free end of the flexible weight 121 continuously drops in the slideway 110 by releasing the flexible weight 121. When the infrared sensor 311 in the sensing unit 310 detects that the flexible weight 121 is close to the predetermined position at the lower part of the slide 110, the sub-control system 300 controls the switch 127 to disconnect the power cable 126, and then brakes the generator motor 123 to reduce its rotation speed, and then brakes the drum brake 1224 to reduce its rotation speed. When the flexible weight 121 drops to the predetermined position at the lower part of the slide 110, the operation controller 320 in the sub-control system 300 first controls the drum brake 1224 to lock the drum 1223 through the communication interface circuit 360, and converts the gravitational potential energy of the flexible weight 121 into electrical energy. During the entire energy release process of the energy storage working unit 100, the gravitational energy release of the flexible weight 121 increases linearly, and the load The stabilizer 125 utilizes elastic force to release energy to linearly reduce the rotation speed of the generator motor 123 to stabilize the rotation speed, and the energy storage working unit 100 can generate electrical energy steadily. Specifically, due to the large height difference between the two ends of the slide 110, when the flexible weight 121 wound on the reel 1223 continues to descend into the slide 110, as the gravity gradually increases, the torque of the gravity on the reel 1223 gradually increases linearly, which may cause the unstable generation of electrical energy. As the load stabilizer 125 gradually releases the stored elastic potential energy, the load stabilizer 125 gradually reduces the torque on the reel 1223 linearly, so that the torque acting on the reel 1223 remains constant, thereby making the load of the generator motor 123 stable. If the gravity energy storage device still has energy release requirements, the sub-control system 300 opens the gravity energy storage devices 120 of the remaining corresponding number of energy storage working units 100 in the gravity energy storage device until the entire gravity energy storage device lowers the flexible weights 121 in all energy storage working units 100 to the lower predetermined position of the slideway 110 to achieve full-load energy release. When a single or part of the energy storage working unit 100 is in the process of releasing energy, and the power grid unexpectedly does not need to release energy, the safety protection unit 340 of the sub-control system 300 will disconnect the power cable 126 and brake the generator motor 123 to reduce its speed, and the sub-control system 300 will then control the drum brake 1224 to brake the drum 1223 to reduce its speed. Finally, the sub-control system 300 controls the drum brake 1224 to lock the drum 1223, and the flexible weight 121 in the slideway 110 stays at the current position, and the energy release operation is suspended. If there is a subsequent energy release requirement, the energy storage working unit 100 whose energy release operation is suspended can continue to release energy until the flexible weight 121 reaches the predetermined position at the bottom of the slide 110. The energy release operation of the energy storage working unit 100 is completed, and finally the full-load energy release of the gravity energy storage device is achieved. During the energy release operation, the speed sensor 312 in the sensor unit 310 in the sub-control system 300 detects the speed of the generator motor 123 at any time. When the speed exceeds the set speed range, the operation controller 320 in the sub-control system 300 controls the excitation current voltage of the generator motor 123 through the communication interface circuit 360, so that the speed of the generator motor 123 returns to the set speed range. When the speed of the generator motor 123 cannot return to the set speed range, the safety protection unit 340 shuts down the problematic energy storage working unit 100 through the operation controller 320; at the same time, the code disk sensor 313 in the sensor unit 310 detects the number of turns of the reel 1223 at any time, and the sub-control system 300 senses the real-time energy release margin of the energy storage working unit 100 through the communication interface circuit 360, so that the operation controller 320 can start or stop the energy release of the energy storage working unit 100.

Furthermore, when the gravity energy storage device stores energy according to the energy storage capacity requirement:

When the required energy storage capacity is close to or equal to the energy storage capacity of the entire gravity energy storage device, the sub-control system 300 turns on the gravity energy storage devices 120 of all the energy storage working units 100 in the gravity energy storage device. In all the gravity energy storage devices 120 of the turned-on energy storage working units 100, the operation controller 320 in the sub-control system 300 first controls the drum brake 1224 to release the drum 1223 through the communication interface circuit 360, and then controls the switch 127 to connect the power cable 126, and at the same time starts the generator motor 123 to rotate. The generator motor 123 rotates the drum 1223 at a reduced speed through the first transmission 124, and the drum 1223 passes through the flexible weight 121 wound thereon. When the infrared sensor 311 in the sensing unit 310 detects that the flexible weight 121 has reached the predetermined upper position near the slide 110, the operation controller 320 first controls the switch 127 to disconnect the power cable 126 through the communication interface circuit 360, and brakes the generator motor 123 to reduce its rotation speed, and then controls the drum brake 1224 to brake the drum 1223 to reduce its rotation speed. When the flexible weight 121 finally reaches the predetermined upper position of the slide 110, the sub-control system 300 controls the drum brake 1224 to lock the drum 1223, thereby ending the energy storage operation of the gravity energy storage device. During the energy storage process, the torque generated by the elastic potential energy of the load stabilizer 125 supplements the torque lost due to the reduction in gravity of the flexible weight 121, thereby allowing the energy storage working unit 100 to absorb electrical energy smoothly. During the energy storage operation, the speed sensor 312 in the sensor unit 310 in the sub-control system 300 detects the speed of the generator motor 123 at any time. When the speed exceeds the set speed range, the operation controller 320 in the sub-control system 300 controls the excitation current voltage of the generator motor 123 through the communication interface circuit 360 to make the speed of the generator motor 123 return to the set speed range. When the speed of the generator motor 123 cannot return to the set speed range, the safety protection unit 340 shuts down the problematic energy storage working unit 100 through the operation controller 320; during the energy storage operation, the code disk sensor 313 in the sensor unit 310 in the sub-control system 300 detects the number of turns of the reel 1223 at any time. The sub-control system 300 senses the real-time energy storage margin of the energy storage working unit 100 through the communication interface circuit 360, so that the operation controller 320 can issue an instruction to the energy storage working unit 100 to store energy or stop energy storage.

Furthermore, when the gravity energy storage device releases energy according to the energy release capacity:

When the required energy release capacity is close to or equal to the energy storage capacity of the entire gravity energy storage device, the sub-control system 300 starts all energy storage working units 100. In the gravity energy storage devices 120 of all the activated energy storage working units 100, the operation controller 320 in the sub-control system 300 first controls the switch 127 to connect the power cable 126 through the communication interface circuit 360, and then controls the drum brake 1224 to release the drum 1223. The flexible weight 121 at the upper predetermined position of the slideway 110 pulls the drum 1223 downward to rotate, and the drum 1223 rotates the low-speed shaft of the first transmission 124, and the high-speed shaft of the first transmission 124 rotates the electric generator 123 to generate electricity, thereby realizing the energy release operation. When the infrared sensor 311 in the sensing unit 310 detects that the flexible weight 121 has reached a predetermined lower position near the slide 110, the operation controller 320 in the sub-control system 300 first controls the switch 127 to disconnect the power cable 126 through the communication interface circuit 360, and brakes the generator motor 123 to reduce its rotation speed, and then controls the drum brake 1224 to brake the drum 1223 to reduce its rotation speed. When the flexible weight 121 finally reaches a predetermined depth at the bottom of the slide 110, the sub-control system 300 controls the drum brake 1224 to lock the drum 1223, and the gravity energy storage device ends the energy release operation. During the entire energy release process, the gravity energy release of the flexible weight 121 increases linearly, while the elastic energy release of the load stabilizer 125 decreases linearly, so that the energy storage working unit 100 generates electricity smoothly. During the energy release operation, the speed sensor 312 in the sensing unit 310 detects the speed of the generator motor 123 at any time. When the speed of the generator motor 123 exceeds the set speed range, the operation controller 320 in the sub-control system 300 controls the excitation current voltage of the generator motor 123 through the communication interface circuit 360, so that the speed of the generator motor 123 returns to the set speed range. When the speed of the generator motor 123 cannot return to the set speed range, the safety protection unit 340 shuts down the problematic energy storage working unit 100 through the operation controller 320; during the energy release operation, the code disk sensor 313 in the sensing unit 310 detects the number of turns of the reel 1223 at any time, and the sub-control system 300 senses the real-time energy release margin of the energy storage working unit 100 through the communication interface circuit 360, so that the operation controller 320 can issue an instruction to the energy storage working unit 100 to release or stop energy release.

Referring to FIG8 , a power generation system 400 provided in an embodiment of the second aspect of the present disclosure includes a general control system 430 and at least one wind farm 410 that supplies power to a main power grid 500 through a gravity energy storage device 420. The gravity energy storage device 420 adopts the gravity energy storage device provided in the embodiment of the first aspect of the present disclosure, and a boost control device 450 is further connected between the gravity energy storage device 420 and the main power grid 500. Each wind farm 410 is configured with at least three gravity energy storage devices 420, and the maximum rated power generation power of the wind farm 410 is equal to the energy storage power of one gravity energy storage device 420. When the wind farm 410 generates electricity, one and only one gravity energy storage device 420 is in an energy storage state, that is, it is performing an energy storage operation (to avoid the problem of the wind farm tripping due to excessive load). (a) one gravity energy storage device 420 is in an energy release state, i.e., it is supplying power to the main grid 500, and at least one other gravity energy storage device 420 is in a state after storing energy at full load, and is ready to supply power to the main grid 500; the wind farm 410, the boost control device 450, and the sub-control systems 300 in each gravity energy storage device 420 are all connected to the general control system 430 through the control cable 200, and power is transmitted between the wind farm 410, the gravity energy storage device 420 and the main grid 500 through the power cable 440; the general control system 430 is used to open and close the corresponding gravity energy storage device 420 for energy storage and output power to the main grid 500 according to the power generation and operation status of the wind farm 410, and monitor the operation status of the power generation system 400.

In some embodiments, the wind farm 410 includes a plurality of wind turbine generator sets 411, a wind farm power collection system 412, and a wind farm control system 413. Each wind turbine generator set 411 is connected to the wind farm power collection system 412 through a power cable 440, and the wind farm power collection system 412 is connected to the power cable 126 in each energy storage working unit 100 in the gravity energy storage device 420 through the power cable 440, and each power cable 126 is first connected to the boost control device 450 through the power cable 440 and then connected to the main power grid 500 through the power cable 440. The wind farm power collection system 412 is connected to the wind farm control system 413 through the control cable 200, and the wind farm control system 413 is connected to the main control system 430 through the control cable 200.

Furthermore, the structure of the overall control system 430 is basically the same as that of the sub-control system 300 in the gravity energy storage device 420, except that the overall control system 430 is not provided with a sensor unit, which will not be described in detail here.

The operation process of the power generation system provided by the second embodiment of the present disclosure is now described as follows:

During energy storage operation: the wind farm control system 413 sends the power value that the wind farm can generate and the power scale for a period of time in the future (such as the next 4 hours) to the general control system 430 in real time. The general control system 430 sends an energy storage operation instruction to a gravity energy storage device 420 that is not in full load energy storage through its internal operation controller. The operation controller of the sub-control system 300 of the gravity energy storage device 420 starts the corresponding number of energy storage working units 100 in the gravity energy storage device 420. At the same time, the general control system 430 sends instructions to the wind farm control system 413 to control the wind farm. The field power collection system 412 is connected to the power cable 440, and the gravity energy storage device 420 that receives the energy storage operation instruction starts to store energy. During the energy storage operation, the operation controller of the overall control system 430 obtains various data of the gravity energy storage device 420 and the wind farm 410 in real time through the communication interface circuit 360 and issues control instructions, obtains the real-time status of the gravity energy storage device 420 and the wind farm 410 through the monitoring unit 350, and issues control instructions through the safety protection unit 340 to ensure the safety of personnel, equipment and facilities in the gravity energy storage device 420 and the wind farm 410. When the gravity energy storage device 420 reaches full load energy storage, the main control system 430 sends a command to the sub-control system 300 to end the current energy storage operation of the gravity energy storage device, and sends a storage operation command again to a gravity energy storage device 420 that has released energy, and the operation controller 320 of the sub-control system 300 of the gravity energy storage device 420 that receives the energy storage operation command starts the corresponding number of energy storage working units 100 in the gravity energy storage device 420. When the power generation value of the wind farm 410 cannot meet the starting power of any energy storage working unit 100 in the gravity energy storage device 420, the main control system 430 sends a command to the wind farm control system 413 to control the wind power collection system 412 to cut off the power cable 440, and at the same time, the main control system 430 sends a command to the sub-control system 300 of the gravity energy storage device 420 that is performing energy storage operation to shut down the energy storage working unit 100 that is performing energy storage operation.

During the energy release operation: the general control system 430 preferentially sends the energy release demand instruction of the general power grid 500 to a gravity energy storage device 420 that has stored energy at full load, and the gravity energy storage device 420 starts the energy release operation, and the operation controller 320 of its sub-control system 300 controls the closing switch 127, and the corresponding energy storage working unit 100 starts the energy release operation. During the energy release operation, the general control system 430 obtains various data of the gravity energy storage device 420 and the wind farm 410 in real time through the communication interface circuit 360 and issues control instructions, obtains the real-time status of the gravity energy storage device 420 and the wind farm 410 through the monitoring unit 350, and issues safety control instructions through the safety protection unit 340 to ensure the safety of personnel, equipment and facilities in the gravity energy storage device 420 and the wind farm 410, and connects to the main power grid 500 through the boost control device 450. The boost control device 450 is responsible for increasing the voltage of the power generation system to a voltage value acceptable to the main power grid until the energy release is completed. When the gravity energy storage device 420 finishes releasing energy, the overall control system 430 sends the current energy release demand instruction of the main grid 500 to another gravity energy storage device 420 that has stored energy at full load, and the power generation system continues to generate electrical energy until all the gravity energy storage devices 420 of the power generation system 400 can no longer meet the power supply demand of the main grid 500. The overall control system 430 controls the boost control device 450 to disconnect the power cable 440 between the main grid 500 and the main grid 500.

The power generation system 400 has at least one wind farm 410 (or photovoltaic farm (similar in layout and function to the wind farm 410 in the power generation system)), equipped with 3 or more, or even 24 gravity energy storage devices 420, each of which can at least meet the energy storage needs of the wind farm 410 (or photovoltaic farm) for 2 hours of power generation at rated power. The power generation system 400 can solve the problem of harmonic interference and unstable output of wind power generation (or photovoltaic) on the main power grid due to natural reasons.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

Although embodiments of the present disclosure have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the claims and their equivalents.

Claims (10)

1. The gravity energy storage device utilizing the relief height difference is characterized by comprising a sub-control system and a plurality of energy storage working units, wherein each energy storage working unit is connected with the sub-control system through a control cable;

the energy storage working unit comprises a slideway arranged by utilizing a relief height difference and a gravity energy storage device matched with the slideway, wherein the gravity energy storage device comprises a flexible heavy object, a dragging mechanism, a first transmission and a generator motor which are sequentially connected, the generator motor is connected with a power cable of a wind power or photovoltaic power generation system through a power cable, and the height of the flexible heavy object in the slideway is changed through the dragging mechanism to realize energy storage and energy release; the dragging mechanism comprises a fixed pulley, a winding drum and a winding drum brake, one end of the flexible heavy object is positioned in a slideway, the other end of the flexible heavy object winds around the fixed pulley positioned on the top end of the slideway and is wound on the winding drum positioned on one side of the top end of the slideway, the winding drum is sleeved on a winding drum shaft, one end of the winding drum shaft is connected with a low-speed shaft of the first speed changer, a high-speed shaft of the first speed changer is connected with the generator motor, a switch is arranged on a power cable, and the winding drum brake, the switch and the generator motor are connected with the sub-control system through the control cable;

the sub-control system is used for switching on or off corresponding quantity of the energy storage working units according to the energy storage or energy release capacity requirement of the total control system of the wind power or photovoltaic power generation system, controlling and monitoring the equipment states in the energy storage working units, transmitting the states and parameters of the gravity energy storage device to the total control system, and regulating and controlling the gravity energy storage device again according to the instruction sent by the total control system;

The sub-control system comprises a first operation controller, a sensing unit, a first networking control unit, a first safety protection unit, a first monitoring unit, a first communication interface circuit and a first user interface, wherein the sensing unit, the first networking control unit, the first safety protection unit, the first monitoring unit, the first communication interface circuit and the first user interface are connected with the first operation controller; the sensing unit comprises an infrared sensor, a rotating speed sensor and a code wheel sensor, wherein the infrared sensor is used for detecting whether one end of the flexible heavy object is positioned at the lowest position and the highest position in the slideway, the rotating speed sensor is used for detecting the rotating speed of the generator motor, the code wheel sensor is used for detecting the rotating number of the winding drum, when the rotating speed of the generator motor detected by the rotating speed sensor exceeds a set rotating speed range, the first operation controller controls exciting current and voltage of the generator motor to enable the rotating speed of the generator motor to operate in the set rotating speed range, and the first operation controller senses the real-time energy storage and energy release allowance of the energy storage working unit according to the rotating number of the winding drum detected by the code wheel sensor; the first grid-connected control unit is used for merging the electric energy generated by the gravity energy storage device to a main power grid; the first safety protection unit is used for handling emergency, and when the parameters exceed a preset working range, the energy storage working unit with problems is timely closed, and even the whole gravity energy storage device is closed; the first monitoring unit is used for monitoring the working state of the energy storage working unit in real time and transmitting data to the first operation controller, the first safety protection unit and the first user interface; the first communication interface circuit is used for realizing data communication in the working process of the gravity energy storage device; the first user interface is used for inputting user instructions, changing parameters and displaying the running state, data and fault conditions of the gravity energy storage device; the first operation controller is used for monitoring the operation of the gravity energy storage device, and comprises start-stop control, control of each electronic device and power grid monitoring;

the sub-control system controls the working modes of each energy storage working unit according to the energy storage and release instructions of the total control system of the wind power or photovoltaic power generation system: when the power generation energy of the wind power generation field or the photovoltaic power generation field is less, the total control system instructs the sub-control system of the gravity energy storage device to start a single or a plurality of energy storage working units to participate in energy storage; when the power generation energy of the wind power generation field or the photovoltaic power generation field is close to full load, the total control system instructs the sub-control system to start all energy storage working units to participate in energy storage at the same time; when the power generation energy of the wind power generation field or the photovoltaic power generation field gradually increases, the total control system instructs the sub-control system to start a single or a plurality of energy storage working units to participate in energy storage successively.

2. The gravity energy storage device according to claim 1, wherein the slideway is installed on the ground or a hillside or a building with a height difference of at least 50 meters, at least 3 slideways are arranged in the gravity energy storage device, a water outlet is arranged at the bottom end of the slideway, the included angle between the slideway and the horizontal plane is not less than 35 degrees, no broken line type turning is arranged in the slideway, and each turning has a radius of curvature of more than 10 meters.

3. The gravity energy storage device according to claim 1, wherein the flexible weight is made of flexible material with a mass of more than 5000 kg and an average density of more than 3000 kg/cubic meter, and a safety distance is reserved between the lowest position and the highest position of one end of the flexible weight in the slideway and two ends of the slideway respectively.

4. A gravity energy storage device according to claim 1, wherein a load stabilizer is provided at the other end of the spool shaft, which eliminates the effect of gravity variations due to the flexible weight in the slideway on the spool and generator motor torque by absorbing and releasing elastic potential energy.

5. The gravity energy storage device according to claim 4, wherein the load stabilizer includes an elastic member and a second transmission, the other end of the spool shaft is connected to a high speed shaft of the second transmission, and is transferred to the elastic member after being decelerated by the second transmission, and the elastic member gradually changes torque to the spool and the generator motor in a linear rule so that torque acting on the spool and the generator motor is kept constant.

6. The gravity energy storage device according to claim 5, wherein the resilient member is a coil spring having a linear characteristic and the second transmission is a planetary transmission.

7. The gravity energy storage device according to any one of claims 1 to 6, wherein the operation thereof comprises:

When the energy storage operation is carried out: the sub control system opens the gravity energy storage equipment of the corresponding energy storage working units according to the energy storage capacity requirement of the total control system, in the gravity energy storage equipment of the opened energy storage working units, the sub control system firstly starts the dragging mechanism and then connects the power cable so as to start the generator motor, and the dragging mechanism is utilized to lift one end of the flexible heavy object which is positioned in the slideway and does not reach the highest position in the slideway; when the flexible weight reaches the highest position in the adjacent slideway, the sub-control system firstly disconnects the power cable, brakes the generator motor to reduce the rotating speed of the generator motor, and then controls the dragging mechanism to reduce the lifting speed of the flexible weight; when one end of the flexible weight reaches the highest position in the slideway, the sub-control system controls the dragging mechanism to keep one end of the flexible weight motionless, so that the surplus electric energy is converted into gravitational potential energy of the flexible weight, and the gravitational potential energy is stored; if surplus electric energy is needed to be stored, the sub-control system continues to open the gravity energy storage equipment of the rest energy storage working units until the whole gravity energy storage device lifts one end of the flexible weight in all the energy storage working units to the highest position in the slideway, so that full-load energy storage is realized, and the energy storage operation is finished; when a single or partial energy storage working unit is in an energy storage process, the sub-control system disconnects the power cable and brakes the generator motor to reduce the rotating speed of the generator motor, then controls the dragging mechanism to stop one end of the flexible heavy object at the current position in the slideway, and the energy storage operation is suspended, if the energy storage requirement is met, the energy storage working unit suspended with the energy storage operation continues the energy storage operation until one end of the flexible heavy object reaches the highest position in the slideway, so that the full-load energy storage of the energy storage working unit is realized, and finally the full-load energy storage of the gravity energy storage device is realized;

when the energy release operation is performed: the sub control system opens the gravity energy storage equipment of the corresponding energy storage working units according to the required energy release capacity, in the gravity energy storage equipment of the opened energy storage working units, the sub control system firstly switches on the power cable to start the generator motor, and then controls the dragging mechanism to continuously descend one end of the flexible heavy object in the slideway by releasing the flexible heavy object; when one end of the flexible weight reaches the lowest position in the adjacent slideway, the sub-control system disconnects the power cable, brakes the generator motor to reduce the rotating speed of the generator motor, and controls the dragging mechanism to reduce the descending speed of the flexible weight; when one end of the flexible weight reaches the lowest position in the slideway, the sub-control system controls the dragging mechanism to keep one end of the flexible weight motionless, so that the gravitational potential energy of the flexible weight is converted into electric energy; if the gravity energy storage device has energy release requirements, the control system opens the gravity energy storage equipment of the other corresponding energy storage working units until the whole gravity energy storage device descends one end of the flexible weight in all the energy storage working units to the lowest position in the slideway, so that full-load energy release is realized; when a single or part of energy storage working units release energy, the sub-control system firstly breaks the power cable and brakes the generator motor to reduce the rotating speed of the generator motor, then controls the dragging mechanism to stop one end of the flexible heavy object at the current position in the slideway, and if the energy release requirement is met, the energy storage working units which are suspended to release energy continue to release energy until one end of the flexible heavy object reaches the lowest position in the slideway, so that full-load energy release of the energy storage working units is realized, and finally full-load energy release of the gravity energy storage device is realized.

8. The power generation system is characterized by comprising a total control system and at least one wind power or photovoltaic power generation field for supplying power to a main power grid through a gravity energy storage device, wherein the gravity energy storage device adopts the gravity energy storage device according to any one of claims 1-7, and a boost control device is further connected between the gravity energy storage device and the main power grid; each wind power or photovoltaic power generation plant is provided with at least three gravity energy storage devices, the maximum rated power of the wind power or photovoltaic power generation plant is equal to the energy storage power of one gravity energy storage device, when the wind power or photovoltaic power generation plant generates electricity, one gravity energy storage device performs energy storage operation, one gravity energy storage device performs energy release operation, and at least one gravity energy storage device is in a full-load energy storage state; the wind power or photovoltaic power generation field, the boosting control device and the sub control systems in the gravity energy storage devices are all connected with the total control system through control cables, and electric power transmission is carried out among the wind power or photovoltaic power generation field, the gravity energy storage devices and the main power grid through electric power cables;

The total control system is used for starting and closing the corresponding gravity energy storage device to store energy and output electric energy to the main power grid according to the power generation condition and the operation condition of the wind power or photovoltaic power generation field, and monitoring the operation condition of the power generation system.

9. The power generation system of claim 8, wherein the overall control system comprises a second operational controller and a second grid-tie control unit, a second safety protection unit, a second monitoring unit, a second communication interface circuit, and a second user interface connected thereto; the second grid-connected control unit is used for merging the electric energy generated by the gravity energy storage device into a main power grid; the second safety protection unit is used for handling emergency, and when the parameters exceed a preset working range, the energy storage working unit with problems is timely closed, and even the whole gravity energy storage device is closed; the second monitoring unit is used for monitoring the working state of the energy storage working unit in real time and transmitting data to the second operation controller, the second safety protection unit and the second user interface; the second communication interface circuit is used for realizing data communication between the total control system and the control system of the wind power or photovoltaic power generation field, the sub-control system and the boost control device; the second user interface is used for inputting user instructions, changing parameters and displaying the running state, data and fault conditions of the gravity energy storage device; the second operation controller is used for operation monitoring of the power generation system and comprises start-stop control, control of all electronic devices and power grid monitoring.

10. The power generation system of claim 8, wherein the power generation system operation comprises:

When the energy storage operation is carried out: the control system of the wind power or photovoltaic power generation field sends the value reached by the power generated by the wind power or photovoltaic power generation field and the power generated in a future period to the total control system in real time, the total control system sends an energy storage operation command to a certain gravity energy storage device which is not in full load energy storage, a sub control system of the gravity energy storage device starts a corresponding number of energy storage working units in the gravity energy storage device, meanwhile, the total control system sends a command to the control system of the wind power or photovoltaic power generation field, a power cable between the wind power or photovoltaic power generation field and the gravity energy storage device is connected, the gravity energy storage device which receives the energy storage operation command starts to store energy, and in the process of energy storage operation, the total control system obtains various data of the gravity energy storage device and the wind power or photovoltaic power generation field in real time and sends a control command, when the gravity energy storage device which executes the energy storage operation reaches full load energy storage, the total control system sends a command to end the current energy storage operation of the gravity energy storage device, and sends a gravity energy storage command again to a certain gravity energy storage device which has been released and receives the gravity energy storage operation command to start the corresponding number of the gravity energy storage devices through the energy storage working units in the sub control system; when the power value of the wind power or the photovoltaic power generation field does not meet the starting power of any energy storage working unit in the gravity energy storage device, the total control system sends an instruction to a control system of the wind power or the photovoltaic power generation field so as to cut off a power cable between the wind power or the photovoltaic power generation field and the gravity energy storage device, and meanwhile, the total control system gives an instruction to a sub-control system of the gravity energy storage device which is performing energy storage operation so as to stop the energy storage working unit which is performing energy storage operation;

When the energy release operation is performed: the energy release demand instruction of the main power grid is preferentially sent to a gravity energy storage device with full energy storage by the main control system, the gravity energy storage device starts energy release operation, the sub control system opens a corresponding energy storage working unit to start energy release operation, in the energy release operation process, the main control system obtains various data of the gravity energy storage device and the wind power or photovoltaic power generation field in real time and sends out control instructions, when the energy release of the gravity energy storage device is finished, the current energy release demand instruction of the main power grid is sent to another gravity energy storage device with full energy storage, the power generation system continues to send out electric energy until all gravity energy storage devices in the power generation system cannot meet the power supply demand of the main power grid, and the boost control device is controlled by the main control system to disconnect a power cable between the gravity energy storage device and the main power grid.