JP2004336933A

JP2004336933A - Power supplying system

Info

Publication number: JP2004336933A
Application number: JP2003131669A
Authority: JP
Inventors: Kazuyoshi Umezawa; 一喜梅沢
Original assignee: Fuji Electric Systems Co Ltd
Current assignee: Fuji Electric Co Ltd
Priority date: 2003-05-09
Filing date: 2003-05-09
Publication date: 2004-11-25
Anticipated expiration: 2023-05-09
Also published as: JP3928798B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit constitution suitable for a power supplying system having an uniterruptible power supply unit for supplying power to a demand load, a commercial power supply and a generator as the constitution unit of a cogeneration system. <P>SOLUTION: The generated power of the generator 6a as the constitution unit of the cogeneration system 6 is converted into a DC power by a link rectifier 9. This DC power is supplied to the DC side of the AC-DC converter 8a of an uninterruptible power supply unit 8. Thus, this generator 6a does not need the linkage operation with the commercial power supply 1. Accordingly, a stable operating state can be maintained without an influence of voltage disturbance, etc. of the commercial power supply 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
この発明は、交流／直流変換回路とこの変換された直流電圧を所望の交流電圧に変換するＣＶＣＦインバータと前記交流／直流変換回路の直流側に接続される蓄電池とからなる無停電電源装置と、前記交流／直流変換回路の交流側に接続される商用電源などの受電系統と、コージェネレーションシステムの構成機器としての発電機とからなる電力給電システムに関する。
【０００２】
【従来の技術】
この種の従来の電力給電システムでは、コージェネレーションシステムの構成機器としての発電機の出力は商用電源などの受電系統に接続される構成が一般的である。（例えば、特許文献１参照）
図５は、前記特許文献１を含む従来の電力給電システムの回路構成図を示し、１は電力系統としての商用電源、２は商用電源１と図示の受電系統との間に設置される遮断器、３は一般負荷２０と前記受電系統との間に設置される遮断器、４は重要負荷３０に瞬時電圧低下や停電の影響を及ぼさないようにするために設置され、直流電圧または直流電流が制御可能な交流／直流変換器４ａとＣＶＣＦインバータ４ｂと蓄電池４ｃとからなる無停電電源装置、５は前記交流／直流変換器４ａの交流側に一端が接続される遮断器、６は熱エネルギーにより駆動される原動機６ａとこの原動機６ａに連結された発電機６ｂなどを構成機器としたコージェネレーションシステム、７は発電機６ｂの出力に一端が接続される遮断器、１０は前記受電系統と遮断器５，７それぞれの他端との間に設置され、高速に遮断することが可能なＡＣスイッチ、１１は商用電源１の停電を検出し、このときにはＡＣスイッチ１０に遮断指令を発する停電検出器、１２は商用電源１の電圧と発電機６ｂの出力電圧とを同期させるために、原動機６ａ，発電機６ｂそれぞれの動作状態を制御する連系運転制御回路である。
【０００３】
【特許文献１】
特開２００１−６１２３８号公報（第４頁−６頁、第１図）
【０００４】
【発明が解決しようとする課題】
図５に示した従来の電力給電システムによると、商用電源１とコージェネレーションシステム６の構成機器としての発電機６ａとは連系運転を必要とし、従って、例えば商用電源１に停電が発生したときには、法的規制などにより、いわゆる単独運転を防止するために発電機６ｂも停止せざるを得えないため、無停電電源装置４を構成する蓄電池４ａの容量も重要負荷３０が消費する電力を十分に供給するために大型化し、従って高価格になるという問題があった。
【０００５】
また、商用電源１の電圧急変などの外乱による発電機６ｂへの影響を最小限にして発電機６ｂを安定に運転するために、高速に遮断することが可能なＡＣスイッチ１０を図示の位置に備える必要があり、このＡＣスイッチ１０は大電流の電力用半導体素子などから形成されることから高価であるという問題もあった。
【０００６】
この発明の目的は、上記問題点を解消するコージェネレーションシステムの構成機器としての発電機を含む電力給電システムを提供することにある。
【０００７】
【課題を解決するための手段】
この第１の発明は、可逆の交流／直流変換回路とこの変換された直流電圧を所望の交流電圧に変換するＣＶＣＦインバータと前記交流／直流変換回路の直流側に接続される蓄電池とからなる無停電電源装置と、前記交流／直流変換回路の交流側に接続される商用電源などの受電系統と、コージェネレーションシステムの構成機器としての発電機と、この発電機の出力側と前記交流／直流変換回路の直流側との間に設置されるリンク整流器と、前記無停電電源装置，前記発電機，前記リンク整流器それぞれの動作状態を指令する動作制御回路とを備え、
前記無停電電源装置に接続される重要負荷の消費電力が前記発電機の出力容量より小さいときには、前記動作制御回路からの動作信号により前記発電機から前記重要負荷に電力を供給するとともに、この発電機の余剰電力を前記受電系統に接続される一般負荷に供給することを特徴とした電力給電システムにする。
【０００８】
第２の発明は前記機器それぞれを備え、前記受電系統からピーク電力カットの要請が発せられているときには、前記動作制御回路からの動作信号により前記発電機は前記無停電電源装置に接続される重要負荷と前記受電系統に接続される一般負荷の双方に電力を供給することを特徴とした電力給電システムにする。
【０００９】
第３の発明は前記機器それぞれを備え、前記コージェネレーションシステムから発電指令が発せられているときには、前記動作制御回路からの動作信号により前記発電機を運転状態にするとともに、この発電電力を前記無停電電源装置に接続される重要負荷と前記受電系統に接続される一般負荷の双方、または、前記重要負荷のみに供給することを特徴とした電力給電システムにする。
【００１０】
第４の発明は前記機器それぞれを備え、前記発電機が運転中には、前記動作制御回路からの動作信号により前記交流／直流変換回路の直流側から前記蓄電池に向かって流れる電流をほぼ零にすることを特徴とした電力給電システムにする。
【００１１】
第５の発明は前記機器それぞれを備え、前記受電系統が停電状態のときには、前記動作制御回路からの動作信号により前記発電機を運転状態にするとともに、この発電電力を前記無停電電源装置に接続される重要負荷のみに供給することを特徴とした電力給電システムにする。
【００１２】
この発明によれば、コージェネレーションシステムの構成機器としての発電機の出力端はリンク整流器を介して無停電電源装置の可逆の交流／直流変換回路の直流側に接続する構成にしたことにより、前記発電機は商用電源と連系運転する必要がないことから安定な運転ができる。
【００１３】
【発明の実施の形態】
図１は、この発明の電力給電システムの実施の形態を示す回路構成図であり、この図において、図５に示した従来例構成と同一機能を有するものには同一符号を付している。
【００１４】
すなわち、図１に示した電力給電システムでは従来の無停電電源装置４に代えて、ＰＷＭ整流器などから形成され、可逆で且つ直流電圧または直流電流が制御可能な交流／直流変換器８ａと、ＣＶＣＦインバータ８ｂと、蓄電池８ｃとからなる無停電電源装置８を備え、また、コージェネレーションシステム６の構成機器としての発電機６ｂの出力端は遮断器７と、直流電圧または直流電流が制御可能なリンク整流器７とを介して無停電電源装置８の交流／直流変換回路８ａの直流側に接続する構成にし、さらに、商用電源１，コージェネレーションシステム６，無停電電源装置８，リンク整流器９それぞれの状態信号からコージェネレーションシステム６，無停電電源装置８，リンク整流器９それぞれの動作信号を指令する動作制御回路４０を備えている。
【００１５】
図１に示したこの発明の電力給電システムの動作を、図２〜図４に示す電力の流れ図を参照しつつ、以下に説明する。
【００１６】
なお、図２〜図４において、破線矢印は電力の流れる方向を示している。
【００１７】
先ず、図２は商用電源１が健全で、重要負荷３０の消費電力がコージェネレーションシステム６の発電容量より大きいときの電力の流れ図であって、このときには商用電力１の電力は受電系統を介して一般負荷２０に給電するとともに、無停電電源装置８の交流／直流変換器を介して重要負荷３０にも給電する。この動作状態のときには、コージェネレーションシステム６の発電機は定格出力以下の状態で、このときの発電電力はリンク整流器９を介することにより直流電力に変換され、この直流電力は無停電電源装置８のＣＶＣＦインバータを介して重要負荷３０に供給されるとともに、無停電電源装置８の蓄電池にも供給される。従って、無停電電源装置８の交流／直流変換器から前記蓄電池への充電電流はほぼ零の状態になっている。
【００１８】
次に、図３は商用電源１が健全で、重要負荷３０の消費電力がコージェネレーションシステム６の発電容量より小さいときの電力の流れ図であって、このときには、コージェネレーションシステム６の発電機は定格出力以下の状態で、この発電機とリンク整流器９とによって得られる直流電力は、無停電電源装置８のＣＶＣＦインバータを介して重要負荷３０に供給されるとともに、無停電電源装置８の蓄電池にも供給され、さらに、余剰の直流電力は無停電電源装置８の交流／直流変換器を介して一般負荷２０にも供給される。また、一般負荷２０には商用電力１からも給電される。従って、このときにも、無停電電源装置８の交流／直流変換器から前記蓄電池への充電電流はほぼ零の状態になっている。
【００１９】
また、図４は商用電源１の停電が発生したときの電力の流れ図であって、このときには、コージェネレーションシステム６の発電機は定格出力以下の状態で、この発電機とリンク整流器９とによって得られる直流電力と、無停電電源装置８の蓄電池から得られる直流電力とを加算した直流電力が無停電電源装置８のＣＶＣＦインバータを介して重要負荷３０に供給される。また、このときには一般負荷２０への給電も停止される。
【００２０】
なお、図２〜図４に示した電力の流れ図の動作例では、コージェネレーションシステム６の発電機は常時運転状態にあることから、無停電電源装置８の蓄電池の容量は小さくでき、また、重要負荷３０に対して、商用電源１の瞬時停電が補償できる程度の容量でよい場合には、蓄電池に代えて小型，安価な電気二重層コンデンサに置き換えることも可能である。
【００２１】
また、図１に示したこの発明の電力給電システムにおいては、前記受電系統でのピーク電力カットの要請が発せられているときには、動作制御回路４０により図３の電力の流れ図と同様の動作状態にして、コージェネレーションシステム６の発電機６ｂは定格電力以下の状態で、このときの発電電力がリンク整流器９を介して無停電電源装置８に接続される重要負荷３０と前記受電系統の一般負荷２０の双方に供給することにより、このピーク電力カットの要請に対応することができる。
【００２２】
さらに、図１に示したこの発明の電力給電システムにおいては、コージェネレーションシステム６の図示しない熱負荷などから要請で発電指令が発せられたときには、動作制御回路４０によりコージェネレーションシステム６の発電機６ｂを運転状態にするとともに、図２の流れ図に示す如く、この発電電力がリンク整流器９を介することにより、無停電電源装置８に接続される重要負荷３０のみに供給する動作状態、または図３の流れ図に示す如く、重要負荷３０と一般負荷２０の双方に供給する動作状態にすることができる。
【００２３】
【発明の効果】
この発明によれば、コージェネレーションシステムの構成機器としての発電機の出力端はリンク整流器を介して無停電電源装置の可逆の交流／直流変換回路の直流側に接続する構成にしたことにより、前記発電機は商用電源と連系運転する必要がないことから、極一般的な発電機の制御方法でも安定な運転ができ、また、前記無停電電源装置を構成する蓄電池の容量もより少なくすることができることからシステム全体の動作信頼性が改善されるとともに、小型，低価格にすることができる。
【図面の簡単な説明】
【図１】この発明の実施の形態を示す電力給電システムの回路構成図
【図２】図１の動作を説明する電力の流れ図
【図３】図１の動作を説明する電力の流れ図
【図４】図１の動作を説明する電力の流れ図
【図５】従来例を示す電力給電システムの回路構成図
【符号の説明】
１…商用電源、２，３，５，７…遮断器、４，８…無停電電源装置、６…コージェネレーションシステム、９…リンク整流器、１０…ＡＣスイッチ、１１…停電検出器、１２…連系運転制御回路、２０…一般負荷、３０…重要負荷、４０…動作制御回路。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides an uninterruptible power supply comprising an AC / DC converter, a CVCF inverter for converting the converted DC voltage into a desired AC voltage, and a storage battery connected to the DC side of the AC / DC converter. The present invention relates to a power supply system including a power receiving system such as a commercial power supply connected to the AC side of the AC / DC conversion circuit and a generator as a component device of a cogeneration system.
[0002]
[Prior art]
In this type of conventional power supply system, the output of a generator as a component device of a cogeneration system is generally connected to a power receiving system such as a commercial power supply. (For example, see Patent Document 1)
FIG. 5 shows a circuit configuration diagram of a conventional power supply system including the above-mentioned Patent Document 1, wherein 1 is a commercial power supply as a power system, 2 is a circuit breaker installed between the commercial power supply 1 and the illustrated power receiving system. 3 is a circuit breaker installed between the general load 20 and the power receiving system, and 4 is installed to prevent the critical load 30 from being affected by an instantaneous voltage drop or power failure. An uninterruptible power supply comprising a controllable AC / DC converter 4a, a CVCF inverter 4b, and a storage battery 4c, 5 is a circuit breaker having one end connected to the AC side of the AC / DC converter 4a, and 6 is heat energy. A cogeneration system including a driven prime mover 6a and a generator 6b connected to the prime mover 6a as components, 7 is a circuit breaker having one end connected to the output of the generator 6b, 10 is the power receiving system. An AC switch that is installed between the other ends of the breakers 5 and 7 and that can be cut off at high speed. A power cut 11 detects a power cut of the commercial power supply 1 and issues a cut command to the AC switch 10 at this time. Reference numeral 12 denotes an interconnection operation control circuit for controlling the operation states of the prime mover 6a and the generator 6b in order to synchronize the voltage of the commercial power supply 1 and the output voltage of the generator 6b.
[0003]
[Patent Document 1]
JP 2001-61238 A (Pages 4-6, FIG. 1)
[0004]
[Problems to be solved by the invention]
According to the conventional power supply system shown in FIG. 5, the commercial power supply 1 and the generator 6a as components of the cogeneration system 6 need to be connected to each other. Therefore, for example, when a power failure occurs in the commercial power supply 1, Due to legal regulations, the generator 6b must be stopped to prevent the so-called islanding operation. Therefore, the capacity of the storage battery 4a constituting the uninterruptible power supply 4 is sufficient for the power consumed by the important load 30. There is a problem that the size is increased in order to supply the oil to the car, and therefore the price becomes high.
[0005]
Further, in order to minimize the influence on the generator 6b due to disturbance such as a sudden change in the voltage of the commercial power supply 1 and to operate the generator 6b stably, the AC switch 10 capable of shutting off at a high speed is moved to the position shown in the figure. It is necessary to provide the AC switch 10, and there is also a problem that the AC switch 10 is expensive because it is formed from a high-current power semiconductor element or the like.
[0006]
An object of the present invention is to provide a power supply system including a generator as a component device of a cogeneration system that solves the above problems.
[0007]
[Means for Solving the Problems]
The first aspect of the present invention is a wireless communication system comprising a reversible AC / DC converter, a CVCF inverter for converting the converted DC voltage to a desired AC voltage, and a storage battery connected to the DC side of the AC / DC converter. A power failure power supply device, a power receiving system such as a commercial power supply connected to the AC side of the AC / DC conversion circuit, a generator as a component device of a cogeneration system, an output side of the generator and the AC / DC conversion A link rectifier installed between the circuit and the DC side, and an operation control circuit for commanding an operation state of each of the uninterruptible power supply, the generator, and the link rectifier,
When the power consumption of the important load connected to the uninterruptible power supply is smaller than the output capacity of the generator, power is supplied from the generator to the important load by an operation signal from the operation control circuit. Power supply system for supplying surplus power of the machine to a general load connected to the power receiving system.
[0008]
The second invention includes each of the devices, and when a request for peak power cut is issued from the power receiving system, the generator is connected to the uninterruptible power supply by an operation signal from the operation control circuit. A power supply system is characterized in that power is supplied to both a load and a general load connected to the power receiving system.
[0009]
According to a third aspect of the present invention, when the power generation command is issued from the cogeneration system, the generator is brought into an operation state by an operation signal from the operation control circuit, and the generated power is converted to the non-power. An electric power supply system characterized by supplying power to both an important load connected to a power failure power supply device and a general load connected to the power receiving system, or to only the important load.
[0010]
According to a fourth aspect of the present invention, each of the devices is provided, and when the generator is operating, the current flowing from the DC side of the AC / DC conversion circuit toward the storage battery is reduced to substantially zero by an operation signal from the operation control circuit. Power supply system.
[0011]
According to a fifth aspect of the present invention, each of the devices is provided, and when the power receiving system is in a power outage state, the generator is operated by an operation signal from the operation control circuit, and the generated power is connected to the uninterruptible power supply. Power supply system characterized by supplying power only to the important loads to be performed.
[0012]
According to the present invention, the output terminal of the generator as a component device of the cogeneration system is configured to be connected to the DC side of a reversible AC / DC conversion circuit of the uninterruptible power supply via a link rectifier. The generator can be operated stably because it does not need to be connected to the commercial power supply.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a circuit configuration diagram showing an embodiment of a power supply system according to the present invention. In this figure, components having the same functions as those of the conventional configuration shown in FIG.
[0014]
That is, in the electric power supply system shown in FIG. 1, instead of the conventional uninterruptible power supply 4, an AC / DC converter 8a formed of a PWM rectifier or the like, which is reversible and can control a DC voltage or a DC current, and a CVCF An uninterruptible power supply 8 comprising an inverter 8b and a storage battery 8c is provided. An output terminal of a generator 6b as a component of the cogeneration system 6 has a circuit breaker 7 and a link capable of controlling a DC voltage or a DC current. It is configured to be connected to the DC side of the AC / DC conversion circuit 8a of the uninterruptible power supply 8 via the rectifier 7, and furthermore, the state of the commercial power supply 1, the cogeneration system 6, the uninterruptible power supply 8, and the link rectifier 9 Operation control circuit 4 for instructing operation signals of cogeneration system 6, uninterruptible power supply 8, and link rectifier 9 from signals It is equipped with a.
[0015]
The operation of the power supply system of the present invention shown in FIG. 1 will be described below with reference to power flow charts shown in FIGS.
[0016]
In FIGS. 2 to 4, broken arrows indicate the direction in which power flows.
[0017]
First, FIG. 2 is a power flow chart when the commercial power supply 1 is sound and the power consumption of the important load 30 is larger than the power generation capacity of the cogeneration system 6. At this time, the power of the commercial power supply 1 is transmitted via the power receiving system. The power is supplied to the general load 20 and also to the important load 30 via the AC / DC converter of the uninterruptible power supply 8. In this operation state, the generator of the cogeneration system 6 is in a state of being equal to or lower than the rated output, and the generated power at this time is converted to DC power through the link rectifier 9, and the DC power is The power is supplied to the important load 30 via the CVCF inverter and also to the storage battery of the uninterruptible power supply 8. Therefore, the charging current from the AC / DC converter of the uninterruptible power supply 8 to the storage battery is almost zero.
[0018]
Next, FIG. 3 is a power flow chart when the commercial power supply 1 is sound and the power consumption of the important load 30 is smaller than the power generation capacity of the cogeneration system 6. In this case, the generator of the cogeneration system 6 The DC power obtained by the generator and the link rectifier 9 in the state of the output or less is supplied to the important load 30 via the CVCF inverter of the uninterruptible power supply 8 and also stored in the storage battery of the uninterruptible power supply 8. The surplus DC power is supplied to the general load 20 via the AC / DC converter of the uninterruptible power supply 8. The general load 20 is also fed from the commercial power 1. Therefore, also at this time, the charging current from the AC / DC converter of the uninterruptible power supply 8 to the storage battery is almost zero.
[0019]
FIG. 4 is a flow chart of electric power when a power failure of the commercial power supply 1 occurs. At this time, the generator of the cogeneration system 6 has a rated output or less and is obtained by the generator and the link rectifier 9. The DC power obtained by adding the obtained DC power and the DC power obtained from the storage battery of the UPS 8 is supplied to the important load 30 via the CVCF inverter of the UPS 8. At this time, the power supply to the general load 20 is also stopped.
[0020]
In the operation examples of the power flow diagrams shown in FIGS. 2 to 4, since the generator of the cogeneration system 6 is always in the operating state, the capacity of the storage battery of the uninterruptible power supply 8 can be reduced. If the load 30 needs to have a capacity that can compensate for an instantaneous power failure of the commercial power supply 1, a small and inexpensive electric double-layer capacitor can be used instead of the storage battery.
[0021]
In the power supply system of the present invention shown in FIG. 1, when a request for cutting off the peak power in the power receiving system is issued, the operation control circuit 40 sets the same operation state as the power flow diagram in FIG. Then, the generator 6b of the cogeneration system 6 is in a state of the rated power or less, and the generated power at this time is connected to the uninterruptible power supply 8 via the link rectifier 9 and the general load 20 of the power receiving system. , It is possible to meet the demand for the peak power cut.
[0022]
Further, in the power supply system of the present invention shown in FIG. 1, when a power generation command is issued by a request from a heat load or the like (not shown) of the cogeneration system 6, the generator 6b of the cogeneration system 6 is operated by the operation control circuit 40. 2 is operated, and as shown in the flowchart of FIG. 2, the generated power is supplied to only the important load 30 connected to the uninterruptible power supply 8 through the link rectifier 9, or the operation of FIG. As shown in the flow chart, an operation state in which both the important load 30 and the general load 20 are supplied can be set.
[0023]
【The invention's effect】
According to the present invention, the output terminal of the generator as a component device of the cogeneration system is configured to be connected to the DC side of a reversible AC / DC conversion circuit of the uninterruptible power supply via a link rectifier. Since the generator does not need to be connected to the commercial power supply, stable operation can be performed even with a very common generator control method, and the capacity of the storage battery constituting the uninterruptible power supply should be reduced. As a result, the operation reliability of the entire system is improved, and the size and cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram of a power supply system according to an embodiment of the present invention. FIG. 2 is a power flow diagram for explaining the operation of FIG. 1. FIG. 3 is a power flow diagram for explaining the operation of FIG. FIG. 5 is a power flow diagram for explaining the operation of FIG. 1. FIG. 5 is a circuit configuration diagram of a power supply system showing a conventional example.
DESCRIPTION OF SYMBOLS 1 ... Commercial power supply, 2, 3, 5, 7 ... Circuit breaker, 4, 8 ... Uninterruptible power supply, 6 ... Cogeneration system, 9 ... Link rectifier, 10 ... AC switch, 11 ... Power failure detector, 12 ... System operation control circuit, 20: general load, 30: important load, 40: operation control circuit.

Claims

An uninterruptible power supply comprising a reversible AC / DC conversion circuit, a CVCF inverter for converting the converted DC voltage into a desired AC voltage, and a storage battery connected to the DC side of the AC / DC conversion circuit; A power receiving system such as a commercial power supply connected to the AC side of the DC / DC conversion circuit, a generator as a component of the cogeneration system, and an output side of the generator and a DC side of the AC / DC conversion circuit. A link rectifier installed in the power supply, an operation control circuit for instructing an operation state of each of the uninterruptible power supply, the generator, and the link rectifier,
When the power consumption of the important load connected to the uninterruptible power supply is smaller than the output capacity of the generator, power is supplied from the generator to the important load by an operation signal of the operation control circuit, Power supply system for supplying surplus power to a general load connected to the power receiving system.

An uninterruptible power supply comprising a reversible AC / DC conversion circuit, a CVCF inverter for converting the converted DC voltage into a desired AC voltage, and a storage battery connected to the DC side of the AC / DC conversion circuit; A power receiving system such as a commercial power supply connected to the AC side of the DC / DC conversion circuit, a generator as a component of the cogeneration system, and an output side of the generator and a DC side of the AC / DC conversion circuit. A link rectifier installed in the power supply, an operation control circuit for instructing an operation state of each of the uninterruptible power supply, the generator, and the link rectifier,
When a request for peak power cut is issued from the power receiving system, the generator is driven by an operation signal from the operation control circuit so that the generator is connected to an important load connected to the uninterruptible power supply and a general load connected to the power receiving system. Power supply system for supplying power to both of the power supply systems.

An uninterruptible power supply comprising a reversible AC / DC conversion circuit, a CVCF inverter for converting the converted DC voltage into a desired AC voltage, and a storage battery connected to the DC side of the AC / DC conversion circuit; A power receiving system such as a commercial power supply connected to the AC side of the DC / DC conversion circuit, a generator as a component of the cogeneration system, and an output side of the generator and a DC side of the AC / DC conversion circuit. A link rectifier installed in the power supply, an operation control circuit for instructing an operation state of each of the uninterruptible power supply, the generator, and the link rectifier,
When a power generation command is issued from the cogeneration system, the generator is put into an operation state by an operation signal from the operation control circuit, and the generated power is connected to the important load connected to the uninterruptible power supply and the load. A power supply system for supplying power to both general loads connected to a power receiving system or only to the important loads.

An uninterruptible power supply comprising a reversible AC / DC conversion circuit, a CVCF inverter for converting the converted DC voltage into a desired AC voltage, and a storage battery connected to the DC side of the AC / DC conversion circuit; A power receiving system such as a commercial power supply connected to the AC side of the DC / DC conversion circuit, a generator as a component of the cogeneration system, and an output side of the generator and a DC side of the AC / DC conversion circuit. A link rectifier installed in the power supply, an operation control circuit for instructing an operation state of each of the uninterruptible power supply, the generator, and the link rectifier,
A power supply system, wherein the current flowing from the DC side of the AC / DC conversion circuit toward the storage battery is made substantially zero by an operation signal from the operation control circuit while the generator is operating.

An uninterruptible power supply comprising a reversible AC / DC conversion circuit, a CVCF inverter for converting the converted DC voltage into a desired AC voltage, and a storage battery connected to the DC side of the AC / DC conversion circuit; A power receiving system such as a commercial power supply connected to the AC side of the DC / DC conversion circuit, a generator as a component of the cogeneration system, and an output side of the generator and a DC side of the AC / DC conversion circuit. A link rectifier installed in the power supply, an operation control circuit for instructing an operation state of each of the uninterruptible power supply, the generator, and the link rectifier,
When the power receiving system is in a power failure state, the generator is brought into an operation state by an operation signal from the operation control circuit, and the generated power is supplied only to an important load connected to the uninterruptible power supply. Power supply system.