JPH11103540A - Uninterruptible power supply system - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the function and reduce the size and cost of an uninterruptible power supply system that receives power from two AC power sources and supplies power to two sets of AC and DC load groups that require uninterruptible power supply. SOLUTION: Two sets of common power supply systems 1 and 2 having the same configuration and the same function to receive power from two systems of AC power supplies I and II, and a power supply line capable of replacing any of the two common power supply systems by switching the power supply lines. A communication unit 3 is provided. For example, in the commercial power supply system 1, the AC power from the power supply I is directly transmitted to the AC load 15 via the AC switch 11, and the AC / DC power bidirectional conversion inverter receiving the direct power is provided. The battery 14 is charged through the power switch 13 and the power switch I or the AC switch 1
In the event of a failure of the inverter 1, the AC conversion output of the inverter 13 is supplied to the AC load 15 using the battery 14 as a power source. Power supply to 15 is continued without interruption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a stable power supply to two sets of loads, each of which receives power from two AC power sources and has a DC load including a battery and an AC load requiring uninterrupted power supply. To an uninterruptible power supply system.

[0002]

2. Description of the Related Art As a conventional uninterruptible power supply system of this type, there is known an example in which the configuration is illustrated in a main circuit connection diagram of FIG. FIG. 4 is a diagram showing an AC power source which receives power from two AC power sources, i.e., a power source I and a power source II. The main circuit configuration of an uninterruptible power supply system that supplies power to a first load group consisting of a load 15 and a second load group consisting of a battery 24, a DC load 26, and an AC load 25 that requires uninterruptible power supply, respectively. It is.

In FIG. 4, a power supply I is connected via a transformer Tr1.
Regarding the regular power supply system 5 that receives more power, 51 and 52 are SC
An AC switch configured to connect and control semiconductor control elements such as R in antiparallel to each other to open and close an AC power path in a non-contact manner, an inverter 53 for converting power from DC to AC, and a rectifier 54. CB51 to CB53 are the contacts of the circuit breaker, MC51
.About.MC53 are contacts of the electromagnetic contactor, all of which are shown in the open state when the a contact, which is closed when the operating coil is excited, when not excited.

The circuit configuration and circuit functions of the service power supply system 6 receiving power from the power supply II via the transformer Tr2 are completely the same as those of the service power supply system 5, and the display numbers of the components having the same functions are those of FIG. The digit is shown as 6 instead of 5 in the service feed system 5. CB81 is an AC-side power supply bus communication circuit breaker for interconnecting the AC-side power supply buses of the two-sided power supply system and receiving power from the power supply II of the service power supply system 5 or receiving power from the power supply I of the service power supply system 6. Contact point.

[0005] Further, regarding the auxiliary power supply system 7, reference numerals 71 and 72 denote the same AC switch as in the above 51, 73 denotes the same inverter as in the above 53, and MC71 and MC72 denote contacts of the same electromagnetic contactor as the above MCs. It is. The MC 73 interconnects the DC-side power supply buses of the two power supply systems, and
Of the DC output of the rectifier 64 of the service power supply system 6 to the inverter 53 of the service power supply system 6 or the inverter 6 of the service power supply system 6
3 is a contact point of a DC-side power supply bus connecting electromagnetic contactor for supplying a DC output of the rectifier 54 of the service power supply system 5 to the DC power supply 3.

In the above two power supply systems, the CB81 and MC73 and MC71 or MC72 or MC72 for busbar communication during the normal operation.
CB and MC contacts are closed except for
Further, the AC switches 51 and 61 are closed and all others are open by ON or OFF control of the respective control elements. In the above state, for example, in the ordinary power supply system 5, the AC power received from the power source I via the Tr 1 is converted into DC power by the rectifier 54 and supplied to the battery 14 and the DC load 16, and the DC input to the inverter 53. Further, the AC conversion output of the inverter is supplied to the AC load 15 via the AC switch 51 in the ON state.

[0007] The load power supply operation in the service power supply system 6 is exactly the same as the power supply operation in the service power supply system 5. Further, in the auxiliary power supply system 7, the AC switches 71 and 72
However, the inverter 73 is supplied with DC power by the service power supply system 5 or 6 via the MC 71 or MC 72 and stands by in a synchronous operation state.

Each of the inverters is operated synchronously with one of the power supplies I and II, which are branch power supplies from the same power supply such as a commercial power supply. Regarding the stability of the AC load power supply when any abnormality occurs in the uninterruptible power supply system having the main circuit configuration as described above, the following applies to the regular power supply system 5 and the AC load 15.

1) When the rectifier 54 fails, the AC switch 5
1 to form an AC bypass power supply system for the rectifier 54 and the inverter 53,
Either use the battery 14 as a DC power supply for the inverter 53 and perform an AC conversion operation within a limited time corresponding to the state of charge, or supply DC power to the inverter 53 from the battery 24 or the rectifier 64 of the service power supply system 6 by closing the MC 73. The AC power supply to the AC load 15 is continued by selecting either the AC conversion operation or the AC conversion operation.

2) When the inverter 53 fails, the AC switch 51 is opened and the AC switch 52 is closed to form an AC bypass power supply system for the rectifier 54 and the inverter 53, or the AC switch 71 and the MC 71 are connected. The circuit is closed and the inverter 73 is operated instead of the inverter 53 to continue the AC power supply to the AC load 15. 3) In the event of an instantaneous power failure of the power supply I, the inverter 53
Receiving DC power from AC power supply 4, AC power supply to AC load 15 is continued.

4) When a continuous power failure occurs only in the power supply I, the AC load 1
Continue the AC power supply to 5. 5) When a continuous power failure occurs simultaneously with the power supply I and the power supply II, the AC load is supplied to the AC load 15 for a limited time corresponding to the state of charge of the battery 14. As described above, in the conventional uninterruptible power supply system whose main circuit configuration is illustrated in FIG. The stability of the power supply to the load is considerably high. In addition, measures to be taken when an abnormality occurs in the service power supply system 6 are the same as those in the service power supply system 5 described above.

[0012]

The main circuit configuration shown in FIG. 4 as a conventional example of an uninterruptible power supply system for stably supplying power to both AC and DC loads requiring uninterruptible power supply is as follows.
Two sets of the normal power supply system and its spare power supply system are provided for the two sets of load groups, and two AC power supply systems and a combination of batteries are used. With the flexibility, it has high stability against load power supply.

However, the conventional uninterruptible power supply system configured as described above has a large scale due to the configuration including two sets of rectifiers and three sets of inverters. The size of the cooling device to cope with heat radiation from the equipment has been increased, and the price of the entire system has been increased. In view of the above, the present invention provides an uninterruptible power supply system that provides stable power supply to both AC and DC loads that require uninterruptible power supply, and achieves a more compact and inexpensive system as a whole with more functions. It is intended to be provided.

[0014]

In order to achieve the above object, in an uninterruptible power supply system according to the present invention, 1) The invention according to claim 1 receives power from two AC power sources and connects a DC load including a battery to an uninterruptible power supply. An uninterruptible power supply system for supplying power to two sets of loads each having an AC load requiring a power supply, comprising an AC switch comprising a semiconductor element and an inverter for performing bidirectional conversion between AC and DC power. As an element, AC power from an AC power supply through the AC switch is supplied to an AC load and is input to the inverter, and the DC conversion output of the inverter is supplied to a DC load including a battery, or conversely, Two sets of regular power supply systems, each of which is configured to use the battery as its DC power source to function the inverter and supply the AC conversion output to the AC load, A power supply line configured as a basic element with an AC switch, which is provided for mutual power supply to the two sets of AC loads by the two-purpose power supply system and is a semiconductor element for opening and closing a connection circuit between the two-purpose power supply system, as a basic element. A communication unit, a power supply path for enabling the two sets of regular power supply systems to be capable of supplying power from any of the two AC power supplies, and an electric circuit opening / closing operation for opening / closing a power supply path to each load including a battery. And means.

According to a second aspect of the present invention, in the uninterruptible power supply system according to the first aspect, the inverter in the two-way power supply system uses the battery as a DC power source to load current of the AC load and a fundamental wave current thereof. It has an active filter function of supplying a compensation current having a waveform having a polarity opposite to that of the waveform deviation at the detection point of the waveform deviation.

According to a third aspect of the present invention, in the uninterruptible power supply system according to the first aspect, the inverter in the dual power supply system uses the battery as its DC power supply to charge the battery and to receive power from the AC power supply. Is supplied at the power supply point to the AC load, and a peak cut operation function is provided for replacing a part or all of the load required power and appropriately reducing the system received power.

As described above, the present invention performs direct power transmission from an AC power supply to an AC load requiring uninterrupted power supply through an AC switch having a semiconductor configuration, and transfers the directly transmitted AC power to a bidirectional power supply between the AC and DC power. An uninterruptible power supply system is configured on the basis of an AC / DC power supply system for charging a battery and supplying power to another DC load by using the DC conversion output as an input of an inverter that performs conversion. Unlike an inverter in an uninterruptible power supply system, a pre-rectifier for an inverter that performs only DC / AC power conversion is not required. That is, the function of combining the inverter and the rectifier in the conventional system is replaced by a set of inverters that perform bidirectional conversion between AC and DC power.

Further, in the present invention, unlike the inverter in the conventional uninterruptible power supply system, the inverter that performs the bidirectional power conversion is always operated in parallel with the AC power supply. AC power supply to the AC load by DC / AC power conversion operation of the inverter using a battery as its DC power supply, or
Multifunctional control, such as feeding of the active filter compensation current or peak cut control compensation power formed by the required AC conversion to the AC power supply side, becomes possible.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the above drawings, the same reference numerals are given to the components having the same functions as in FIG. 4 showing the conventional example. First, FIG. 1 is a main circuit connection diagram of an uninterruptible power supply system, and shows a first embodiment of the present invention according to claim 1. As in the case of FIG. 4 showing an embodiment of the prior art,
A first system comprising a battery 14, a DC load 16, and an AC load 15 requiring uninterrupted power supply, which receives power from two systems of AC power sources, i.e., a power supply I and a power supply II, and passes through one of the normal power supply systems 1 and 2.
1 illustrates a main circuit configuration of an uninterruptible power supply system that supplies power to a load group and a second load group including a battery 24, a DC load 26, and an AC load 25 that requires uninterruptible power supply.

In FIG. 1, regarding a service power supply system 1 for receiving power from a power supply I via a transformer Tr1, 11 is an AC switch having the same semiconductor configuration as described above, 13 is an inverter for performing bidirectional conversion between AC and DC power, CB11 to CB13 are contacts of a circuit breaker, MC11 is a contact of an electromagnetic contactor, and all are a contacts and are shown in an open state when not excited. The common power supply system 2 that receives power from the power supply II via the transformer Tr2 has exactly the same circuit configuration and circuit function as the common power supply system 1, and the display numbers of the components having the same functions are the tenth digit. It is illustrated as 2 in place of 1 in the regular power supply system 1.

Further, with respect to the feed line connecting portion 3, reference numeral 31 denotes an AC switch similar to that of the above-mentioned 11; CB31 and CB32 represent contacts of a circuit breaker as in the case of the aforementioned CB12; MC31 represents an electromagnetic contactor similar to the aforementioned MC11. Contact point. In the two power supply systems, the contacts of the illustrated CBs and MCs are closed during the normal operation, except for the CB41 for busbar connection and the MC11 and MC21 for bypass formation. By the OFF control, the AC switches 11 and 21 are closed and the AC switch 31 is open.

In the above state, for example, in the ordinary power supply system 1, the AC power received from the power supply I via the Tr 1 is directly supplied to the AC load 15 via the AC switch 11 and is input to the inverter 13. The DC conversion output is supplied to the DC load 16 and used to charge the battery 14. The load power supply operation in the service power supply system 2 is exactly the same as the power supply operation in the service power supply system 1.

In the power supply line communication unit 3, the AC switch 31 is normally open. However, in the ON / OFF phase control, the AC input of the direct power supply or the application of the AC output of the dual power supply system inverter is performed. It is controlled in synchronization with the voltage phase at the time of the loss, and functions so as to supply the AC load 15 or 25 without interruption. The power supply I and the power supply II are usually branched from the same AC system, and the inverters 13 and 23 operating in parallel with the power supply I and the power supply II in the circuit configuration of FIG. 1 are synchronously controlled. Accordingly, the on / off phase synchronization control for the AC switch 31 as described above can be performed.

The stability of the AC load power supply in the uninterruptible power supply system having the main circuit configuration as described above when any abnormality occurs is as follows with respect to the regular power supply system 1 and the AC load 15. 1) When the AC switch 11 fails, the inverter 13 receives the DC power supply from the battery 14 and continues the AC power supply to the AC load 15 without interruption, or the closing operation of the bypass contact MC11 and the synchronization of the inverter 13 with the power supply I. The AC power supply by the inverter 13 is restarted after a short power interruption time required for closing, or the AC switch 31 is closed and the AC power supply is closed to the AC load 15 from the power supply II system in connection with the failure check of the AC switch 11. Continue without interruption,
The power supply to the AC load 15 is continued by selecting any one of the above.

2) When the inverter 13 fails, the AC power supply to the AC load 15 via the AC switch 11 is continued, or in connection with the failure check of the inverter 13, the open circuit between the AC switch 11 and the CB 13 and the AC switch 31 The power supply to the AC load 15 is continued by selecting one of the following methods: closing the circuit and continuing the AC power supply from the power supply II system to the AC load 15.

3) In the event of a momentary power failure of the power supply I, the AC switch 1
The AC power supply to the AC load 15 by the inverter 13 using the battery 14 as its DC power supply is continued with the opening of the circuit 1. 4) When a continuous power failure occurs in both power supply I and power supply II, 3)
The same treatment as that of the instantaneous power failure of the power supply is performed in the two regular power supply systems, and the AC power supply to the AC loads 15 and 25 is continued within a limited period according to the state of charge of each power supply battery.

As described above, the uninterruptible power supply system whose main circuit configuration is shown in FIG. 1 is an AC load that requires uninterruptible power supply, including power supply within a limited period when a continuous power failure occurs simultaneously with the power supplies I and II. The stability of the power supply to is considerably high. The stability of power supply to the AC load in the service power supply system 2 is the same as in the case of the service power supply system 1.

Next, FIG. 2 is a main circuit connection diagram of an uninterruptible power supply system having a function as an active filter, and shows a second embodiment of the present invention according to claim 2, wherein Since the power bidirectional conversion type inverters in the power supply system are always operated in parallel with the respective AC power sources, the two inverters use the batteries forming the respective charging loads as the DC power sources in the opposite direction. An active filter that performs power conversion and controls so that a compensation current for a harmonic current in the AC load current is supplied to the AC load power supply line, and the inverters reduce the harmonics in the current received from the respective AC power supplies. To make it work.

Here, FIG. 2 shows a configuration in which an active filter control device 17 is provided in the ordinary power supply system 1 in FIG. It should be noted that the common power supply system 2 has the same configuration as the common power supply system 1 and is not shown in FIG.
As shown in FIG. 2, the receiving current Is at the receiving point R1 from the AC power supply I, the current at the output point R2 of the inverter 13, that is, the harmonic compensation current Ic by the inverter, and the load current IL at the feeding point R3 to the AC load 15. Are input to the active filter control device 17, where the control command of the harmonic compensation current Ic according to the equation (1) is formed.

ΣIsn = Ic + ΣILn = 0 (n = 2, 3, ‥‥) (1) According to the equation (1), the harmonic compensation current Ic is equal to the load current IL.
And a waveform current having a polarity opposite to the current deviation between the current and the fundamental wave current IL1 (n = 1). Where ΣIsn and ΣILn
(N = 2, 3,...) Indicates the sum of the received current Is and the harmonic current in the load current IL.

A command signal S for forming the harmonic compensation current Ic
a is applied to the inverter 13. Next, FIG. 3 is a main circuit connection diagram of an uninterruptible power supply system having a peak cut operation function, showing a third embodiment of the present invention according to claim 3, wherein both electric powers in the two-way power supply system are used. Since the direction conversion type inverters are always operated in parallel with the respective AC power supplies, the two inverters perform DC / AC power conversion using the batteries forming the respective charging loads as the DC power supplies in reverse. Supplying AC conversion power according to a charging state of the battery and a power receiving state of the service power supply system from the AC power supply at a power supply point to the AC load, and replacing part or all of the load required power with a system The peak cut operation is performed to reduce the received power appropriately.

Here, FIG. 3 shows a configuration in which a peak cut control device 18 is provided in the ordinary power supply system 1 in FIG. Note that the common power supply system 2 has the same configuration as the common power supply system 1 and is not illustrated in FIG. FIG.
As shown in the figure, the received power Ps at the power receiving point R1 from the AC power source I, the power at the output point R2 of the inverter 13, that is, the power Pc for the received power compensation by the inverter, and the power PL supplied to the AC load 15 at the power supply point R3. Are input to the peak cut controller 18, where a control command for the received power compensating power Pc according to equation (2) is formed.

Pc = PL−Ps───── (2) Note that the received power Ps is a regulation value determined by the conditions of the power supply system side, and the compensation power Pc is also the above-mentioned power that forms the power source of the inverter 13. Because the power is limited by the state of charge of the battery, power compensation that completely satisfies Expression (2) may not be performed depending on the value of the required power PL of the AC load 15.

The command signal Sp for forming the received power compensating power Pc is applied to the inverter 13.

[0035]

According to the present invention, an uninterruptible power supply system that receives power from two AC power sources and supplies power to two sets of loads each including a DC load including a battery and an AC load requiring uninterrupted power supply. 1) A semiconductor AC switch and an inverter for performing bidirectional conversion between AC and DC power as basic elements as described above, and direct power transmitted from an AC power supply via the AC switch is supplied to an AC load. Simultaneously with the input of the inverter, the DC conversion output of the inverter is supplied to a DC load including a battery, or conversely, the battery is used as the DC power source to operate the inverter, and the AC conversion output is supplied to the AC load. Two sets of regular power supply systems, each of which is configured to supply power,
Forming a power supply line connecting portion having a circuit configuration based on an AC switch composed of a semiconductor element for opening and closing a connection electric line between the two normal power supply systems provided for mutual power supply to a pair of AC loads, and forming various power supply lines; Combination function of the inverter and the rectifier in the previous stage that performs only one-way power conversion from DC to AC in the conventional uninterruptible power supply system by configuring the uninterruptible power supply system with Can be replaced by a set of inverters that perform bidirectional conversion between AC and DC power, and the required equipment installation area as an uninterruptible power supply system while maintaining high power supply stability for AC loads that require uninterruptible power supply. This makes it possible to reduce the size of the cooling device and cope with the heat radiation of the equipment, thereby making it possible to reduce the cost of the entire system.

2) According to the invention of claim 2, claim 1
In the uninterruptible power supply system according to the present invention, an active filter function is provided to the dual-use power supply system inverter that is always operated in parallel with the AC power supply, thereby eliminating or reducing a harmonic current generated by the AC load. To avoid harmonic outflow to the system side, etc.
Each inverter can be multifunctional.

3) According to the third aspect of the present invention,
In the uninterruptible power supply system according to the present invention, a peak cut operation function using the battery as its DC power supply is provided to the dual power supply system inverter that is always operated in parallel with the AC power supply, and the charging state of the battery and the normal power supply system In response to the above-mentioned regulation value for receiving power from the AC power source, a part or all of the required load power can be substituted to reduce the appropriateness of the system received power and improve the stability of the load power supply.

[Brief description of the drawings]

FIG. 1 is a main circuit connection diagram of an uninterruptible power supply system according to a first embodiment of the present invention.

FIG. 2 is a main circuit connection diagram of an uninterruptible power supply system according to a second embodiment of the present invention.

FIG. 3 is a main circuit connection diagram of an uninterruptible power supply system according to a third embodiment of the present invention.

FIG. 4 is a main circuit connection diagram of an uninterruptible power supply system showing an embodiment of the prior art.

[Explanation of symbols]

 1, 1 and 2 service power supply system 3 power supply path communication section 5, 6 service power supply system 7 standby power supply system 11, 21 (semiconductor) AC switch 13, 23 inverter (bidirectional conversion type) 14, 24 battery 15, 25 AC load 16, 26 DC load 17 Active filter controller 18 Peak cut controller 31 (Semiconductor) AC switch 51, 52 (Semiconductor) AC switch 53, 63 Inverter (one-way conversion type) 54, 64 Rectifier 61, 62 (Semiconductor) AC switch 71 , 72 (Semiconductor) AC switch 73 Inverter (unidirectional conversion type) CB circuit breaker (contact) MC Magnetic contactor (contact) Tr transformer

Claims (3)

[Claims] An uninterruptible power supply system that receives power from two AC power sources and supplies power to two sets of loads each including a DC load including a battery and an AC load requiring uninterruptible power supply. The basic elements are an AC switch composed of an AC switch and an inverter that performs bidirectional conversion between AC and DC power.
The AC power from the AC power supply via the AC switch is supplied to the AC load and input to the inverter, and the DC conversion output of the inverter is supplied to the DC load including the battery, or conversely, the battery is connected to the AC load. Two sets of service power supply systems configured so that the inverter functions as a DC power supply and supplies the AC conversion output to the AC load, and for mutual power supply to the two sets of AC loads by both service power supply systems. A power supply line connecting portion having a circuit configuration including, as a basic element, an AC switch formed of a semiconductor element for opening and closing a connection electric path between the two regular power supply systems;
A pair of regular power supply systems includes a power supply path for enabling power supply from any of the two AC power supplies, and a circuit opening / closing means for opening / closing a power supply path to each load including a battery. An uninterruptible power supply system. 2. The uninterruptible power supply system according to claim 1, wherein the inverter in the two-way power supply system uses the battery as a DC power supply and reverses a waveform deviation between a load current of the AC load and a fundamental current thereof. An uninterruptible power supply system having an active filter function of supplying a compensation current having a polarity waveform at a detection point of the waveform deviation. 3. The uninterruptible power supply system according to claim 1, wherein the inverter in the dual power supply system uses the battery as a DC power supply and performs AC conversion according to a charging state and a power receiving state from the AC power supply. An uninterruptible power supply having a peak cut operation function for supplying electric power at a power supply point to the AC load and replacing a part or all of the required load power to appropriately reduce system received power. Power system.