KR20210087308A - Engine power generation system - Google Patents

Abstract

The present invention relates to an engine power generation system, in a three-phase four-wire output engine power generation system, which includes: an engine which generates torque; a generator which is driven by the engine to generate three-phase AC power; a power conversion device which converts three-phase AC power; and a control unit which detects the occurrence of a power outage and an emergency load receiving power from the power conversion device when a power outage occurs, and changes the phase of a first single-phase power supplied to the engine to control the power conversion device to supply second single-phase power to the emergency load.

Description

Engine power generation system

The present invention relates to a power generation system using an engine, and more particularly, to an engine power generation system for emergency operation when a power outage occurs.

An engine is a device that can generate power using a mixture of fuel and air (mixed fuel), and is used in various industrial fields such as air conditioning systems, automobiles, and power generation facilities.

As an example, the cogeneration system refers to a system that operates an engine with gas fuel to generate electric power from a generator, converts heat generated from the engine, etc. into hot water, and supplies the same to a demanding party. The cogeneration system is operated in connection with a typical commercial power system, and can supply power not only to the load of the air conditioner but also to the loads of other devices inside the building when necessary.

On the other hand, in such a combined heat and power system, when a power failure occurs due to a problem in the system, the power generation system may optionally perform emergency power generation operation. As a representative technology for stably supplying power during a power outage, a technique for supplying power during a power outage using an emergency generator is being used.

The prior art (JP2008228543A) is an invention related to a cogeneration device, and when the power generation system that generates electricity in grid-connected power is exhausted, the engine is started by motoring the generator through the added battery and DC/DC converter, and the system is operated When power generation is possible, it is the content of supplying power to the load and the battery.

However, the power generation system of the prior art, when a power outage occurs, a battery for emergency power generation, an additional power conversion device (eg, DC/DC converter) or a passive element is required, so the system price increases, and emergency situations It is not operated under normal circumstances, so there is a problem of lowering efficiency.

Accordingly, there is a need for an efficient method for stably supplying power to emergency loads such as firefighting equipment loads when a power outage occurs.

An object of the present invention is to provide an engine power generation system capable of supplying power to an emergency load when a power outage occurs in order to solve the above problems.

Another object of the present invention is to provide an engine power generation system that is effective in terms of economy by supplying power to an emergency load without an added power conversion device or an added passive element.

In addition, the present invention is to provide a high-efficiency uninterruptible power supply method.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, an engine power generation system of three-phase, four-wire output according to the present invention includes an engine generating a rotational force, a generator driven by the rotational force generated by the engine to generate three-phase AC power; a power converter for converting a phase AC power and a controller for controlling the power converter to supply a second single-phase power to an emergency load by detecting the occurrence of a power failure and changing a phase of the first single-phase power supplied to the engine; includes

Other specific details of the present invention are included in the detailed description and drawings.

According to the present invention, there are one or more of the following effects.

First, when a power outage occurs, there is an effect that the capacitor of the DC terminal can be charged through switching control without an additional power conversion device.

Second, there is an effect that an efficient emergency power generation operation is possible by boosting the voltage with the DC stage capacitor without a passive element added through the filter.

Third, there is an economic effect by operating emergency power generation using an existing system without separately configuring an emergency generator.

Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a conceptual diagram schematically showing an example of a cogeneration system to which the present invention can be applied.
2 is a schematic diagram showing an example of an engine power generation system to which the present invention can be applied.
3 is a circuit diagram showing an engine power generation system of three-phase, four-wire output.
4 is a circuit diagram illustrating an engine power generation system according to an embodiment of the present invention.
5 is a flowchart illustrating a control method when a power failure occurs in an engine power generation system according to an embodiment of the present invention.
6 is a circuit diagram illustrating an inverter according to an embodiment of the present invention.

Hereinafter, the embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, but the same or similar components are assigned the same reference numerals regardless of reference numerals, and overlapping descriptions thereof will be omitted. The suffixes "module" and "part" for the components used in the following description are given or mixed in consideration of only the ease of writing the specification, and do not have a meaning or role distinct from each other by themselves. In addition, in describing the embodiments disclosed in the present specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in the present specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and the technical spirit disclosed herein is not limited by the accompanying drawings, and all changes included in the spirit and scope of the present invention , should be understood to include equivalents or substitutes.

Terms including an ordinal number, such as first, second, etc., may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

When a component is referred to as being “connected” or “connected” to another component, it is understood that the other component may be directly connected or connected to the other component, but other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that no other element is present in the middle.

The singular expression includes the plural expression unless the context clearly dictates otherwise.

In the present application, terms such as "comprises" or "have" are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

1 is a conceptual diagram schematically showing an example of a cogeneration system to which the present invention can be applied.

The combined heat and power system refers to a system that operates an engine with gas fuel to generate electricity from a generator, converts heat generated from the engine, etc. into hot water, etc.

An air conditioner may be connected to the cogeneration system to supply electric power and heat or hot water to the air conditioner.

The gas fuel may be supplied while always maintaining a constant outlet pressure regardless of the shape of the inlet input or the change in flow rate by the zero governor 12 . The zero governor 12 can obtain a stable outlet pressure over a wide range, and has a function of adjusting the pressure of gas fuel supplied to the engine to be almost constant in the form of atmospheric pressure. In addition, the zero governor 12 may be provided with two solenoid valves to block the supplied fuel.

The air may be filtered and supplied as clean air through an air cleaner 14 . The air cleaner 14 may block the mixing of moisture and oil in the form of dust and mist by using a filter for external air supplied to the engine.

The gaseous fuel and air supplied in this way may be sucked into the engine by a mixer 16 having a constant mixing ratio of air and fuel.

A fuel valve 13 is provided at the inlet side of the mixer 16 to control the supply amount of gas fuel mixed with air. When a large amount of gas fuel is supplied, the mixing ratio of the air-fuel mixture is increased.

The turbocharger 20 may compress the mixer in a high-temperature and high-pressure state. The turbocharger 20 is a device that rotates a turbine with the power of exhaust gas, compresses intake air with the rotational force, and sends it to the cylinder of the engine to increase output.

The turbocharger 20 is a term that is a combination of a turbo (turbine) and a supercharger (supercharger), and is composed of a turbine and an air compressor directly connected thereto to rotate a turbine wheel with energy of exhaust gas. The air sucked in by the air compressor can be compressed and sent to the cylinder.

The turbocharger 20 has a structure in which a blade-installed turbine wheel and an impeller of an air compressor are connected to one shaft and each surrounded by a housing, and may be disposed near the exhaust manifold of the engine.

Since the mixture is compressed by the turbocharger 20 to increase the temperature, it may be cooled by an intercooler 25 and then introduced into the engine 30 through the intake manifold 32 . The intercooler 25 cools the mixer to increase the density, thereby increasing the absolute amount of the mixer introduced into the engine, thereby improving engine output.

The intercooler 25 may be configured as an air-cooled heat exchanger for cooling with air or a water-cooling heat exchange path for cooling with water.

The water-cooled intercooler may use cooling water as a medium, and has a separate heat exchanger and a pump to discard heat obtained from the compressed mixer to the outside.

A throttle valve (not shown) may be provided between the intercooler 25 and the intake manifold 32 to control the amount of mixed air flowing into the engine 30 . As the throttle valve, an electronic throttle control valve (ETC valve) is generally used.

In addition, the engine may control various control variables related to the control of the engine through a separate engine control unit (ECU) 31 . For example, the ETC valve 38 and the control cycle of the valve may be controlled by the ECU 31 .

The engine 30 is an internal combustion engine that operates through four strokes of intake, compression, explosion, and exhaust of the mixture introduced through the intake manifold 32 .

Exhaust gas generated as the engine 30 operates is discharged through the exhaust manifold 34 , and at this time, the impeller of the turbocharger 20 is rotated.

The engine 30 rotates the generator 40 to produce power. To this end, a belt may be connected between the pulley 36 provided at one end of the rotating shaft of the engine 30 and the pulley 46 provided at one end of the rotating shaft of the generator 40 .

The pulley 36 of the engine 30 and the pulley 46 of the generator 40 may be provided such that the rotation speed ratio is approximately 1:3. That is, when the engine 30 rotates once, the generator 40 may rotate about 3 times.

The power produced by the generator 40 may be converted into commercial power in which current, voltage, frequency, etc. are converted in the power conversion device 90 , and may be supplied to a power demanding place such as a building or an air conditioner.

On the other hand, since the engine 30 generates considerable heat during operation by gas combustion, heat exchange is performed while circulating the coolant to absorb high-temperature heat generated by the engine.

In automobiles, a radiator is installed in the coolant circulation passage to dispose of all engine waste heat, but in a cogeneration system, heat generated from the engine can be absorbed and used to make hot water.

To this end, a hot water heat exchanger 50 is provided in the cooling water circulation passage to heat exchange between the cooling water and separately supplied water, so that the water receives heat from the high temperature cooling water.

The hot water generated by the hot water heat exchanger 50 may be stored in the hot water storage tank 51 and then supplied to a hot water demanding place such as a building.

When hot water is not used in the hot water demander, water is not supplied to the hot water heat exchanger 50 and the cooling water temperature rises. To prevent this, a separate radiator 70 is installed to transfer the heat of the cooling water that is not needed to the outdoors. can be thrown away

The radiator 70 radiates heat by heat-exchanging high-temperature coolant with air by a plurality of fins, and a heat-dissipating fan 72 may be provided to promote heat dissipation.

The coolant flow path from the engine 30 is branched into the hot water heat exchanger 50 and the radiator 70, and a three-way valve 53 is installed at the branching point to control the flow direction of the coolant depending on the situation. . By the three-way valve 53, the cooling water can be sent only to the hot water heat exchanger 50 or only to the radiator 70, or divided into the hot water heat exchanger 50 and the radiator 70 at a predetermined ratio depending on the situation.

Cooling water that has passed through the three-way valve 53 and radiated heat from the radiator 70 may be combined with the coolant that has passed through the three-way valve 53 and passed through the hot water heat exchanger 50 to be introduced into the engine 30 .

In addition, a cooling water pump 55 may be installed in the cooling water circulation passage to control the flow rate of the cooling water. The coolant pump 55 may be installed downstream of the hot water heat exchanger 50 and the radiator 70 and upstream of the engine 30 in the coolant circulation passage.

On the other hand, the exhaust gas coming out through the exhaust manifold 34 of the engine 30 operates the above-described turbocharger 20, but an exhaust gas heat exchanger 60 may be provided to recover waste heat of the exhaust gas. have.

The exhaust gas heat exchanger 60 is installed between the coolant pump 55 and the engine 30 upstream in the coolant circulation passage, and may be configured to exchange heat between the exhaust gas discharged through the turbocharger 20 and the coolant. . Waste heat of the exhaust gas can be recovered through the exhaust gas heat exchanger 60 .

While passing through the exhaust gas heat exchanger 60 , the coolant is heated to some extent and flows into the engine 30 in a lukewarm state, but the coolant can also sufficiently cool the engine 30 .

Exhaust gas radiated while passing through the exhaust gas heat exchanger 60 passes through the muffler 80 , and noise from the exhaust side of the engine can be reduced by the muffler 80 .

The exhaust gas that has passed through the muffler 80 may be discharged to the outside after passing through the drain filter 85 . The drain filter 85 has a purifying stone built therein to purify the condensed water generated in the muffler 80 and the exhaust gas line, etc., so that the acidic condensate can be purified and neutralized and discharged to the outside.

2 is a schematic diagram showing an example of an engine power generation system to which the present invention can be applied.

Referring to FIG. 2 , the engine power generation system 100 includes an engine 30 for supplying driving force for driving the generator 40 and an engine control unit (ECU) 210 for controlling the engine, and , The generator 40 is connected to a power conversion device (power conversion system; 90) for converting the power generated by the driving of the generator 40 and controlling the amount of power generation.

The power conversion device 90 includes a converter 91 that converts AC power generated by the generator 40 into DC, an inverter 92 that converts DC power converted in the converter 91 into AC, and the converter 91 . and a capacitor C of the DC terminal positioned between the inverter 92 and the inverter 92 .

The converter 91 converts the input AC power produced by the generator 40 into DC power. The converter 91 may use a DC-DC converter operating as a power factor control unit (PFC).

Also, the DC-DC converter may use a boost converter. The converter 91 may include a rectifying unit.

The inverter 92 may include a plurality of inverter switching elements, and may convert the DC power supplied from the converter 91 into an AC power of a predetermined frequency by on/off operation of the switching elements and output the converted power.

At this time, the DC power produced by the generator 40 and supplied through the converter 91 is stored in the capacitor C of the DC stage. The inverter may convert the power stored in the capacitor C of the DC terminal into AC power and output it.

In this way, the load 220 may be driven by the AC power output through the inverter 92 .

The load 220 is various electric devices of power demanders, and may include an air conditioner and other power loads such as lighting. Here, the air conditioner is a device for air conditioning a room using a refrigerant, and may be installed in one or more sets in a building in which an engine power generation system is installed.

For example, if the load 220 is an air conditioner using a three-phase AC motor as a compressor, the inverter 92 may output and supply three-phase AC power for driving the AC motor to the air conditioner.

The load 220 may receive the three-phase AC power output from the power conversion device 90 through a power line. The load 220 may be connected to an external power supply through a power line.

A power switch 300 may be installed in the power line to open and close the power supplied from the engine power generation system 100 to the load 220 . The power switch 300 may supply or block power generated in the cogeneration system, and thus may also be referred to as a circuit breaker.

The controller 200 may control at least one of the engine 30 and the power conversion device 90 . In this case, the control unit 200 may include an engine control unit 210 for controlling the engine.

Such an engine power generation system 100 may be a part of the cogeneration system described with reference to FIG. 1 . However, in some cases, a power generation system separate from the cogeneration system described with reference to FIG. 1 may be configured.

Also, as an example, the engine of the engine power generation system 100 may be a gas engine using gas.

3 is a circuit diagram showing an engine power generation system of three-phase, four-wire output.

Referring to FIG. 3 , the engine power generation system 100 converts an engine 30 generating rotational force, a generator 40 that is driven by the rotational force of the engine 30 to generate 3-phase AC power, and 3-phase AC power It may include a power conversion device 90 and a control unit 200 to the.

The general engine power generation system 100 may be connected to the system in a three-phase three-wire system to generate electricity. However, since the power loads connected to and operated on the system require N-phase as a single phase, and the engine power generation system 100 also uses a single-phase power source in many cases, the final output of the engine power generation system 100 is three-phase, four-wire. It is efficient to connect to the grid with

The engine power generation system 100 to be described below assumes that the final output is three-phase including U-phase, V-phase, and W-phase, and four-wire including N-phase neutral.

The single-phase power of the engine power generation system 100 is connected to the grid. It may be connected to the U-phase of the power conversion device 90 and the N-phase of the system.

The description of FIG. 1 may be applied to the engine 30 , the generator 40 , and the power conversion device 90 of the engine power generation system 100 .

The power conversion device 90 is a converter 91 for converting the power generated by the generator 40, a capacitor C of the DC stage for smoothing the power converted by the converter 91, the power converted by the converter 91 It may include an inverter 92 that converts power that can be supplied to the load 220 .

The description of FIG. 2 may be applied to the converter 91 , the DC terminal capacitor C, and the inverter 92 of the power conversion device 90 .

Although not shown in the drawings, the power conversion device 90 may further include a braking resistor connected to the converter 91 to consume the power converted by the converter 91 when the generator 40 is braked.

When the braking resistor is connected to the converter 91 and the DC terminal capacitor C, the DC power converted by the converter 91 and smoothed from the DC terminal capacitor C may be received to consume power.

The DC stage capacitor C is connected between the converter 91 and the inverter 92 to smooth the DC power converted in the converter 91 and transfer the smoothed DC power to the braking resistor or the inverter 92. have.

The DC terminal capacitor C is charged with DC power rectified by the converter 91 , and the power stored in the DC terminal capacitor C through the inverter 92 may be converted into AC power and output. .

The inverter 92 may receive the smoothed DC power from the DC terminal capacitor C and convert it into AC power.

Referring to FIG. 3 , the converter 91 may include a plurality of switching elements and convert AC power produced by the generator 40 into DC power.

The converter 91 may be implemented simply by a bridge diode. That is, the converter 91 for converting AC to DC may include a bridge diode circuit capable of full-wave rectification of AC.

The inverter 92 may include a plurality of inverter switching elements, convert the DC power output from the converter 91 into a three-phase AC power of a predetermined frequency, and output the converted DC power to the load 220 . Here, the load 220 may be a three-phase motor.

A detailed description of the inverter 92 will be described later with reference to FIG. 6 .

The power conversion device 90 may further include a filter 93 including at least one inductor at the output terminal. Power converted through the inverter 92 may be transmitted to the load 220 as an output voltage through the filter 93 .

The filter 93 is connected to each phase of the output terminal, and may be composed of an inductor L or LCL.

The filter 93 may be located between the power conversion device 90 and the system.

The controller 200 may control at least one of the engine 30 and the power conversion device 90 . In this case, the control unit 200 may include an engine control unit 210 for controlling the engine.

The control unit 200 may be electrically connected to at least one of the engine 30 , the generator 40 , and the power conversion device 90 .

The controller 200 may be implemented as at least one electronic device. The electronic device 201 may include at least one of a memory 140 , an interface unit 180 , a power supply unit 190 , and a processor 170 .

The memory 140 is electrically connected to the processor 170 . The memory 140 may store basic data for the unit, control data for operation control of the unit, and input/output data. The memory 140 may store data processed by the processor 170 . According to an embodiment, the memory 140 may be classified into a sub-configuration of the processor 170 .

The interface unit 180 may exchange signals with at least one electronic device included in the engine power generation system 100 in a wired or wireless manner. The interface unit 180 may be configured with at least one of a communication module, a terminal, a pin, a cable, a port, a circuit, an element, or a device.

The power supply 190 may supply power to the electronic device 201 .

The processor 170 may be electrically connected to at least one of the memory 140 , the interface unit 180 , and the power supply unit 190 to exchange signals. Processor 170, ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), processors (processors), controller It may be implemented using at least one of controllers, micro-controllers, microprocessors, and other electrical units for performing functions.

The processor 170 may be driven by power provided from the power supply 190 . The processor 170 may receive data, process data, generate a signal, and provide a signal while power is supplied by the power supply unit 190 .

The processor 170 may receive information from other electronic devices in the engine power generation system 100 through the interface unit 180 . The processor 170 may provide a control signal to another electronic device in the engine power generation system 100 through the interface unit 180 .

The electronic device 201 may include at least one printed circuit board (PCB). At least one of the memory 140 , the interface unit 180 , the power supply unit 190 , and the processor 170 may be electrically connected to the printed circuit board.

4 is a circuit diagram illustrating an engine power generation system according to an embodiment of the present invention.

Referring to FIG. 4 , the engine power generation system 100 includes an engine 30 , a generator 40 driven by the engine 30 to generate three-phase AC power, and a power conversion device 90 for converting three-phase AC power. ) and a control unit 200 for controlling the power conversion device 90 to supply the second single-phase power to the emergency load 222 by detecting the occurrence of a power failure and changing the phase of the first single-phase power supplied to the engine 30 . ) may be included.

For the engine power generation system 100 , the descriptions of FIGS. 1 to 3 may be applied.

The power converter 90 converts three-phase AC power into DC power and outputs a converter 91 to the DC terminal, a DC terminal capacitor connected to the DC terminal (C, hereinafter referred to as a capacitor), and the DC power to AC power An inverter 92 that converts and outputs the output terminal, a plurality of switches connected to each phase of the output terminal and switched according to a switching signal of the control unit 200, and a battery connected through a first switch between the first phase and the capacitor of the output terminal (94) may be included.

The description of FIGS. 2 to 3 may be applied to the converter 91 , the DC terminal capacitor C, and the inverter 92 of the power conversion device 90 .

The plurality of switches may include at least one of a first switch S1 , a second switch S2 , and a third switch S3 .

At least one of the switches S1 , S2 , and S3 may be configured as a switching element that performs an ON/OFF switching operation. The switching element may be a semiconductor switching element in which ON/OFF operation is performed by a switching operation signal. A switching operation of the switching element may be controlled by the controller 200 .

When a power outage occurs, the controller 200 may control the switching element to cause a switching operation (ON).

When a power failure is detected, the controller 60 may apply a switching signal to the switching element to control the switching element to perform a switching operation (ON).

The first switch S1 may be connected to the first phase of an output terminal (hereinafter, referred to as an output terminal 95) of the power conversion device 90 . According to an embodiment, the first phase may be a W phase. Also, the first switch S1 may be connected to the battery 94 .

That is, the first switch S1 may be disposed between the first phase of the output terminal 95 and the battery 94 .

The first switch S1 may be switched by the first switching signal of the controller 200 . When the first switch S1 is switched, the first phase of the output terminal 95 and the battery 94 may be connected.

The second switch S2 may change the phase of the first single-phase power supplied to the engine 30 according to the second switching signal.

The second switch S2 may be connected to the N-phase of the system. Also, the second switch S2 may be connected to the engine 30 . When the system is connected, the second switch S2 is in an off state, and the engine 30 can receive the first single-phase power supply (S10, see FIG. 3) by the N-phase of the system and the third phase of the output terminal 95. have. According to an embodiment, the third phase may be a U phase.

The second switch S2 may be connected to the second phase of the output terminal 95 by the second switching signal of the controller 200 . According to an embodiment, the second phase may be a V phase.

That is, when a power outage occurs, the second switch S2 is in an on state by the second switching signal, and the engine 30 supplies the first single-phase power by the second and third phases of the output terminal 95 ( S20 ). ) can be obtained.

The third switch S3 may be connected to the second phase or the third phase of the output terminal 95 of the power conversion device 90 . According to an embodiment, the second phase may be a V-phase, and the third phase may be a U-phase. Also, the third switch S3 may be connected to the emergency load 222 .

That is, the third switch S3 may be disposed between the second phase of the output terminal 95 and the emergency load 222 or between the third phase of the output terminal 95 and the emergency load 222 .

The third switch S3 may be switched by a third switching signal of the controller 200 . When the third switch S3 is switched, the second phase of the output terminal 95 and the emergency load 222 may be connected, or the third phase and the emergency load 222 of the output terminal 95 may be connected.

The battery 94 may be connected to the first phase of the output terminal 95 to supply DC power to the capacitor C when a power failure occurs. In this case, the first switch S1 may be switched.

The controller 200 may control the battery to charge the capacitor C through the first switching signal.

The battery 94 is normally used for storing electric power, and may be used for temporarily supplying electric power in an emergency.

The emergency load 222 may include an emergency power source, a fire pump, lighting, and the like. For example, emergency power is a power supply for emergency power supply according to the use of firefighting equipment, a fire pump is a pump for supplying fire water when a sprinkler operates according to the use of firefighting equipment, and lighting means an evacuation light, an evacuation guide light, etc. can do.

The engine power generation system 100 may supply power to the emergency load 222 or the like in an emergency such as a power outage.

That is, according to an embodiment of the present invention, by configuring the system power supply and emergency load power supply through the engine power generation system 100 during normal and power failure, the uninterruptible power supply method using the engine power generation system 100 can be implemented. have.

The controller 200 may control at least one of the engine 30 and the power conversion device 90 . In this case, the control unit 200 may include an engine control unit 210 for controlling the engine.

The control unit 200 may be electrically connected to at least one of the engine 30 , the generator 40 , and the power conversion device 90 .

The control unit 200 may be electrically connected to at least one of the plurality of switches S1 , S2 , and S3 of the power conversion device 90 .

The control unit 200 may detect the occurrence of a power failure and generate a first switching signal for switching the first switch S1 .

The control unit 200 may detect the state of charge of the capacitor C and generate a second switching signal for switching the second phase of the output terminal 95 and the second switch S2 connected to the engine 30 .

The control unit 200 provides a second single-phase power supply to the emergency load 222 by generating a third switching signal for switching the third switch S3 connected between the second phase of the output terminal 95 and the emergency load 222 . can supply

The control unit 200 supplies the second single-phase power to the emergency load 222 by generating a fourth switching signal for switching the fourth switch S4 connected between the third phase of the output terminal 95 and the emergency load 222 . can supply

The switching signal of the control unit 200 will be described in detail with reference to FIG. 5 .

5 is a flowchart illustrating a control method when a power failure occurs in an engine power generation system according to an embodiment of the present invention.

Referring to FIG. 5 , when a power outage occurs, the engine power generation system 100 performs a switching step S100 of the first switch S1, a switching step S200 of the second switch S2, and a third switch S3. It is possible to supply power to the emergency load 222 through the switching step (S300).

The switching step ( S100 ) of the first switch ( S1 ) may include a step ( S110 ) of the controller 200 detecting the occurrence of a power failure and a step ( S120 ) of switching the first switch ( S1 ) ( S120 ).

The step (S110) of detecting the occurrence of a power failure may mean a step in which the control unit 200 detects when the power supply is stopped due to an abnormality such as a power outage in the system power source.

When a power failure occurs and the switch 300 operates, the control unit 200 may receive a power failure signal to detect the occurrence of the power failure.

The step of switching the first switch S1 ( S120 ) may mean a step of switching the first switch S1 by the first switching signal. The switch may be configured as a switching element.

The controller 200 may generate a first switching signal when detecting the occurrence of a power failure. The controller 200 may switch the first switch S1 by applying the first switching signal to the switching element and controlling the switching element to perform a switching operation (ON).

The switching step (S200) of the second switch (S2) includes the steps of charging the capacitor (C) of the DC terminal (S210), checking whether the charging is complete (S220), and switching the second switch (S2) (S230) may be included.

The step of charging the capacitor C of the DC terminal ( S210 ) may mean a step of charging the capacitor C by the battery 94 .

The battery 94 may be connected to the output terminal 95 of the power conversion device 90 by switching the first switch S1 . Specifically, the battery 94 may be connected to the first phase of the output terminal 95 . The first phase of the output terminal 95 may be connected to the first portion 92-1 of the inverter 92 .

The first part 92-1 may serve as a DC/DC converter. The battery 94 may charge the capacitor C by DC/DC conversion of a voltage through the first portion 92-1.

That is, the battery 94 may be connected to the first phase of the output terminal 95 by the first switching signal, and the capacitor C may be charged through the first portion 92-1 of the inverter 92 .

In this case, the voltage from the battery 94 to the capacitor C may be boosted by the filter 93 . The filter 93 may be configured as a passive element. The filter may include an L, LCL filter, and the like.

That is, the filter 93 may be used as a passive element for boosting a voltage from the battery 94 to the capacitor C when a power failure occurs.

The step of confirming whether the charging is completed ( S220 ) may mean a step of the controller 200 confirming whether the charging of the preset voltage to the capacitor C is completed. Confirmation of the completion of charging may be made through a sensor.

If the charging of the preset voltage in the capacitor C is not completed, the controller 200 repeats the step (S210) of charging the capacitor C of the DC terminal until the charging of the preset voltage in the capacitor C is completed. can do.

The step of switching the second switch S2 ( S230 ) may mean a step of switching the second switch S2 by the second switching signal. The switch may be configured as a switching element.

The controller 200 may generate a second switching signal when the capacitor C is fully charged. The controller 200 may switch the second switch S2 by applying the second switching signal to the switching element and controlling the switching element to perform a switching operation (ON).

The switching step (S300) of the third switch (S3) includes the steps of supplying single-phase power to the engine 30 (S310), operating the engine 30 (S320), and checking whether the target speed is reached (S310) S330), the converter 91 ON step (S340), the step of supplying a constant voltage to the capacitor (C) of the DC terminal (S350), the step of switching the third switch (S3) (S360) and the battery 94 It may include a charging step (S370).

The step of supplying single-phase power to the engine 30 ( S310 ) may refer to a step in which the DC terminal capacitor C supplies single-phase power to the engine 30 .

When power (380V/220V) is supplied to the engine power generation system 100 before a power outage occurs, power is supplied to the system electric part and is applied to the capacitor C of the DC terminal through the initial charging circuit of the power conversion device 90 side. The voltage can be charged.

The voltage charged in the capacitor C is output to the output terminal 95 through the inverter 92. At this time, the third phase of the output terminal 95 and the N phase of the system are connected to the engine power generation system 100 again, and the first single phase Power may be supplied (S10). The third phase may be a U phase.

However, when a power outage occurs, the second and third phases of the output terminal 95 may be connected to the engine 30 by the second switching signal to supply the first single-phase power ( S20 ). The second phase may be a V phase.

The engine 30 may be connected to the output terminal 95 of the power conversion device 90 by switching the second switch S2 . Specifically, the engine 30 may be connected to the second phase and the third phase of the output terminal 95 .

That is, when a power outage occurs, the engine 30 may receive the first single-phase power by the voltage difference between the second phase and the third phase.

The second phase and the third phase of the output terminal 95 may be connected to the second part 92 - 2 of the inverter 92 . The capacitor C may supply single-phase power to the engine 30 through the second part 92 - 2 .

The control unit 200 detects the state of charge of the capacitor C, and when the charge of the capacitor C is completed, a second switching signal for switching the second switch S2 connected to the second phase and the engine 30 is provided. can create

The capacitor C may supply the first single-phase power to the engine 30 by converting the DC power into the AC power through the second part 92 - 2 when the second switch S2 is switched.

In other words, the control unit 200 generates a second switching signal and supplies system power through the second part 92 - 2 , thereby driving the system to correspond to the grid connection.

The operation of the engine 30 ( S320 ) and the step of checking whether the target speed is reached ( S330 ) may be the same as the steps of performing general power generation.

The steps of performing general power generation include starting the zero current control by operating the converter 91 of the power conversion device 90, starting the engine and driving the engine at the initial target speed, and applying the power generation amount set at the initial target speed of the engine. It may include at least one of the step of controlling the amount of power generation by changing the engine rotation speed to the target speed and the step of operating the inverter 92 to supply the amount of power to the load 220 .

When a system operator inputs a target power generation amount to the control unit 200 for power generation, the control unit 200 may first start zero current control.

That is, the controller 200 may start the zero current control for the generator output by operating the converter 91 .

Zero current control is to control the output current of the generator 40 to be zero (0), and the power generated from the generator 40 is transferred to the capacitor C (generator -> DC terminal -> grid or load) , Conversely, it may mean a control to prevent the power of the DC stage from being transmitted to the generator 40 (system -> DC stage -> generator).

That is, the zero current control may mean a control that prevents power from being supplied in any direction around the converter 91 .

The zero current control may be a step including a basic process for stably operating the engine power generation system before starting the engine.

As such, when the zero current control is started by the converter 91 , the power conversion device 90 may notify the controller 200 of a state in which the engine can be started.

Thereafter, the control unit 200 may transmit an engine start signal to the engine control unit (ECU) to drive the engine 30 .

Specifically, the controller 200 may control the engine controller to start the engine through the start motor, and then, the engine 30 may operate at an initial target speed.

According to the amount of power input by the system operator, the engine 30 may change the rotation speed to operate at the target speed for the amount of power from the initial target speed. That is, the control unit 200 may receive the target power generation amount from the system operator and operate the engine 30 at the target speed accordingly.

From this point on, the power conversion device 90 may enter the generation amount control for controlling the system according to the power required by the load 220 .

Since there is no power supplied to the load 220 until the inverter 92 operates, the initial generation amount control may have the same effect (result) as the zero current control.

The converter 91 ON step (S340) and the step of supplying a constant voltage to the capacitor C of the DC terminal (S350) start the engine 30 and convert the power produced by the generator 40 to the converter 91. It may refer to a step of outputting through and controlling the amount of power generation through the capacitor (C).

The converter 91 may maintain the voltage of the capacitor C constant at the preset voltage when the engine 30 is driven up to a preset target speed by the first single-phase power source.

The step of switching the third switch S3 ( S360 ) may mean a step of switching the third switch S3 by the third switching signal. The switch may be configured as a switching element.

The third switch S3 may be connected between at least one of the second phase or the third phase of the output terminal 95 and the emergency load 222 . The controller 200 may supply the second single-phase power to the emergency load 222 by generating a third switching signal for switching the third switch.

The control unit 200 may generate a third switching signal if it is possible to supply a constant voltage to the capacitor C of the DC terminal. The controller 200 may switch the third switch S3 by applying the third switching signal to the switching element and controlling the switching element to perform a switching operation (ON).

The emergency load 222 may be connected to the output terminal 95 of the power conversion device 90 by switching the third switch S3 . Specifically, the battery 94 may be connected to the second phase and the third phase of the output terminal 95 . The second phase and the third phase of the output terminal 95 may be connected to the second part 92 - 2 of the inverter 92 .

The second part 92 - 2 may serve as a single-phase inverter. The emergency load 222 may receive a second single-phase power supply through the second part 92 - 2 .

The emergency load 222 may be connected in parallel with the second phase and the third phase by the third switching signal to receive the second single-phase power. The second phase may be a V phase. The third phase may be a U phase.

The step of charging the battery 94 ( S370 ) may refer to a step of recharging the discharged battery 94 to charge the capacitor C when a power outage occurs.

Since power can be supplied to the engine power generation system 100 by the first switching signal and the second switching signal, the discharged battery 94 may be charged at this time.

The capacitor C may charge the battery 94 through the first portion 92-1 of the inverter 92 . The first part 92-1 may serve as a DC/DC converter.

6 is a circuit diagram illustrating an inverter according to an embodiment of the present invention.

Referring to FIG. 6 , when a power outage occurs, the inverter 92 may be used as a first part 92-1 and a second part 92-2.

In order to supply the amount of power to the load, the inverter 92 may operate. The inverter 92 may supply the same power as the system to the load 220 by generating a voltage and frequency of a constant magnitude regardless of the engine rotation speed.

In this way, as the inverter 92 operates, the required electric power (target generation amount) is supplied to the load (consumption load or system) 220 .

That is, the power generated by the generator 40 may be stably supplied to the load 220 according to the target power generation amount only while the inverter 92 is operating. Accordingly, from the standpoint of the load 220 , the required amount of power can be stably supplied without large fluctuations.

Through this process, the control unit 200 may control the engine control unit 210 and the power conversion device 90 to adjust the power generated by the generator 40 to a target power generation amount to stably supply the power to the load 220 .

Specifically, the inverter 92 is a pair of upper switching elements 92-a, 92-c, 92-e and lower switching elements 92-b, 92-d, and 92-f connected in series with each other, respectively. , a total of three pairs of upper and lower switching elements may be connected in parallel to each other.

The switching elements 92-a, 92-b, 92-c, 92-d, 92-e, and 92-f of the inverter 92 may use a power transistor, for example, an insulated gate bipolar transistor. (insulated gate bipolar mode transistor; IGBT) can be used.

The switching device may be an ON/OFF switching device. The switching element may be a semiconductor switching element in which ON/OFF operation is performed by a switching operation signal.

The switching element may be open normally and closed during a switching operation to connect the converter 91 and the load 220 .

The inverter 92 may operate as a DC/DC converter and a single-phase inverter when a power outage occurs.

Referring to FIG. 6 , the DC/DC converter may include a first part 92-1 and the single-phase inverter may include a second part 92-2.

Specifically, the first part 92-1 may include two switching elements 92-e and 92-f, and the second part 92-2 includes four switching elements 92-a, 92-b, 92-c, 92-d).

The first portion 92-1 may be connected to the first phase of the output terminal 95 to charge the capacitor C by the first switching signal.

The second part 92 - 2 may be connected to the second and third phases of the output terminal 95 to supply the first single-phase power to the engine power generation system 100 by the second switching signal ( S20 ). . In addition, the second part 92 - 2 may supply the second single-phase power to the emergency load 222 by the third switching signal.

That is, when a power outage occurs, the engine power generation system 100 may charge the capacitor C through the battery 94 and the first portion 92-1 and supply system power through the second portion 92-2. .

The filter 93 of the output terminal 95 for grid connection may be used as a passive element for boosting the voltage from the battery 94 to the capacitor C of the DC terminal when a power failure occurs.

The present invention described above can be implemented as computer-readable code on a medium in which a program is recorded. The computer-readable medium includes all kinds of recording devices in which data readable by a computer system is stored. Examples of computer-readable media include Hard Disk Drive (HDD), Solid State Disk (SSD), Silicon Disk Drive (SDD), ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc. There is also a carrier wave (eg, transmission over the Internet) that is implemented in the form of. In addition, the computer may include a processor or a control unit. Accordingly, the above detailed description should not be construed as restrictive in all respects but as exemplary. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are included in the scope of the present invention.

100: engine power generation system
30: engine
40: generator
90: power converter
91: converter
92: inverter
93: filter
94: battery
95: output stage
200: control unit
210: ECU
220: load
222: emergency load
300: breaker
C: DC terminal capacitor
1st switch: S1
Second switch: S2
3rd switch: S3

Claims (15)

In the engine power generation system of 3-phase 4-wire output,
engine;
a generator driven by the engine to generate three-phase AC power;
a power converter for converting the three-phase AC power; and
The engine power generation system comprising a; a control unit that detects the occurrence of a power failure and controls the power conversion device to supply a second single-phase power to an emergency load by changing a phase of the first single-phase power supplied to the engine. According to claim 1,
The power conversion device,
a converter converting the three-phase AC power into DC power and outputting it to a DC terminal;
a capacitor connected to the DC terminal;
an inverter converting the DC power into AC power and outputting it to an output terminal;
a plurality of switches connected to each phase of the output terminal and switched according to a switching signal of the control unit; and
and a battery connected through a first switch between the first phase of the output terminal and the capacitor. 3. The method of claim 2,
The control unit is
When detecting the occurrence of the blackout, generating a first switching signal for switching the first switch,
The battery is
An engine power generation system for charging the capacitor by the first switching signal. 4. The method of claim 3,
The inverter is divided into a first part and a second part,
The battery is an engine power generation system for charging the capacitor by DC/DC conversion of a voltage through the first part. 5. The method of claim 4,
The control unit is
detecting the state of charge of the capacitor;
When the charging of the capacitor is completed, the engine power generation system generates a second switching signal for switching the second switch connected to the second phase and the engine of the output terminal. 6. The method of claim 5,
The capacitor is
When the second switch is switched, the engine power generation system supplies the first single-phase power to the engine by converting the DC power to the AC power through the second part. 7. The method of claim 6,
The converter is
When the engine is driven to a preset target speed by the first single-phase power source, the voltage of the capacitor is constantly maintained at a preset voltage.
8. The method of claim 7,
The capacitor is
an engine power generation system for charging the battery via the first portion of the inverter. 3. The method of claim 2,
The emergency load is
An engine power generation system connected in parallel with the second phase of the output stage and the third phase of the output stage. 10. The method of claim 9,
The control unit is
An engine power generation system for supplying the second single-phase power to the emergency load by generating a third switching signal for switching a third switch connected between at least one of the second phase or the third phase of the output stage and the emergency load . 3. The method of claim 2,
The power conversion device,
The engine power generation system further comprising a filter including at least one inductor at the output stage. 12. The method of claim 11,
The filter is
An engine power generation system for charging the capacitor by boosting a voltage from the battery to the capacitor when a power failure occurs. detecting, by the controller, the occurrence of a power failure and switching the first switch by generating a first switching signal;
charging, by a battery, a capacitor of a DC terminal through a first phase of an output terminal connected by the first switching signal;
switching, by the control unit, a second switch by generating a second switching signal;
supplying, by the capacitor, a first single-phase power to the engine through a second phase and a third phase of an output terminal connected by the second switching signal; and
and supplying, by the engine, a second single-phase power to an emergency load by driving it up to a preset target speed. 14. The method of claim 13,
The step of charging the capacitor of the DC stage,
Step, by the filter, boosting the voltage of the battery; and
An inverter, DC/DC conversion of the boosted voltage through a first portion to charge the capacitor; The method of operating an engine power generation system comprising a. 15. The method of claim 14,
The step of supplying the first single-phase power,
and converting, by the inverter, the DC power charged in the capacitor into AC power through a second part.

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