JP2009194952A - Uninterruptible power system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an uninterruptible power system specialized in a main circuit constitution, which supplies to a load sound input AC voltage as it is, and also supplies to the load the abnormal input AC voltage by converting the terminal voltage of a storage battery to a desired AC voltage. <P>SOLUTION: The uninterruptible power system 10 is constituted of a power converter circuit 11, a booster circuit 12 and a control circuit 13 or the like. When the input AC power source 4 is sound, the Q1, Q2, Q5, Q6 in the power converter circuit 11 perform switching in synchronization with a change in the voltage polarity of the input AC power source 4, while the Q3, Q4 in the power converter circuit 11 perform switching at high frequency, and the booster circuit 12 is turned off. When the input AC power source 4 is abnormal, the Q1, Q2 in the power converter circuit 11 are turned off, while the Q3 to Q6 in the power converter circuit 11 perform switching at high frequency, and the booster circuit 12 receiving the terminal voltage of a storage battery facility 5 is operated to continue the operation of the power converter circuit 11 while supplying output DC voltage to a capacitor C1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, when the input AC voltage is healthy, the AC voltage is supplied to the load while passing, and when the input AC voltage is abnormal, the terminal voltage of the storage battery is converted to a desired AC voltage to the load. The present invention relates to a power supply device to be supplied.

  FIG. 3 is a circuit configuration diagram showing a conventional example of this type of power supply apparatus. The power supply apparatus 1 includes a bidirectional conversion circuit 2, a contactor 3, and a sequence circuit (not shown) formed using a known semiconductor power conversion technique. 4 is an input AC power supply such as a commercial power supply, 5 is a storage battery facility, and 6 is a load of the power supply device 1.

  In this power supply device 1, when the input AC power supply 4 is healthy, the contactor 3 is closed by a command from the sequence circuit, whereby the AC voltage of the input AC power supply 4 is supplied to the load 6. The bidirectional conversion circuit 2 that receives this AC voltage is converted into a DC voltage for charging the storage battery facility 5.

  Further, a power failure occurs in the input AC power supply 4 from a state in which the input AC power supply 4 performing the above operation is healthy. The voltage of the input AC power supply 4 is within a predetermined range, for example, −12% of the power failure or the rated voltage. In an abnormal state such as deviating from the range of + 20%, in the power supply device 1, the sequence circuit detects this and shifts the contactor 3 from the closed state to the open state, and this transition operation is performed. When completed, an AC voltage is generated by the bidirectional conversion circuit 2 that receives the terminal voltage of the storage battery facility 5 and supplied to the load 6. The voltage at both ends of the load 6 at this time is substantially equal to the voltage of the input AC power supply 4 applied during soundness.

As prior art documents related to the invention of this application, there are the following.
JP 2006-25540 A

  In the conventional power supply apparatus 1 shown in FIG. 3, the abnormal state as described above occurs in the input AC power supply 4 while the voltage of the input AC power supply 4 is being applied to the load 6 while the input AC power supply 4 is healthy. Then, after the contactor 3 is shifted to the open circuit state, the voltage of the input AC power supply 4 and the bidirectional conversion circuit 2 are changed until the power supply to the load 6 by the storage battery facility 5 and the bidirectional conversion circuit 2 is started. In order to prevent damage to the bidirectional conversion circuit 2 due to overlap with the output voltage, a no-voltage period of at least several milliseconds is required, and during this period, power supply to the load 6 is interrupted. It was.

  An object of the present invention is to provide a low-cost uninterruptible power supply apparatus while solving the above problems.

According to the present invention, a first arm, a second arm, and a third arm formed by connecting two antiparallel connection circuits of a self-extinguishing semiconductor element and a diode in series are connected in parallel to each other, and It is formed by connecting one end of one reactor to the intermediate connection point of the second arm and connecting the reactor side end of the output filter formed by connecting the second reactor and the second capacitor in series to the intermediate connection point of the third arm. A power conversion circuit that converts the terminal voltage of the storage battery equipment into a boosted DC voltage, applies the DC voltage to both ends of the first capacitor, one end of the input AC power supply to the power conversion circuit, and the second An intermediate connection point of one arm is connected, and the other end of the input AC power supply is connected to the other end of the first reactor and the capacitor side end of the output filter, and to a load connected to both ends of the second capacitor. In the uninterruptible power supply unit and a control circuit for controlling the operation of the power conversion circuit and booster circuit for supplying a flow voltage,
In the control circuit, when the input AC power source is healthy, the first arm and the third arm perform a switching operation in synchronization with a change in the voltage polarity of the input AC power source, while the second arm is the input AC power source. The switching operation is performed at a frequency higher than the frequency, the booster circuit is disabled, and when the input AC power supply is abnormal, the first arm is disabled and the second arm and the third arm are switched at a high frequency. In addition to operating, the booster circuit is operated.

  According to the present invention, the above-described no-voltage period is not required, and the circuit configuration that suppresses the increase in price is used, so that the power supply to the load can be interrupted while maintaining the function of the conventional power supply device. It is possible to provide a power supply that does not exist, that is, an uninterruptible power supply.

  FIG. 1 is a circuit configuration diagram of an uninterruptible power supply device showing an embodiment of the present invention.

  In the power conversion circuit 11 of the uninterruptible power supply 10, a first arm formed by serially connecting Q1 and Q2 of IGBTs (insulated gate bipolar transistors) as self-extinguishing semiconductor elements each having a diode connected in antiparallel. , A second arm formed by serially connecting IGBTs Q3 and Q4 each having a diode connected in antiparallel, and a third arm formed by connecting IGBTs Q5 and Q6 each connected by an antiparallel diode in series. Each of C1 is mutually connected in parallel. Further, one end of the reactor L1 is connected to the intermediate connection point of the second arm, and the reactor L2 side end of the output filter formed by connecting the reactor L2 and the capacitor C2 in series is connected to the intermediate connection point of the third arm. .

  Further, the booster circuit 12 formed by a known chopper circuit or the like is used when the terminal voltage of the storage battery facility 5 is converted to a boosted DC voltage and this DC voltage is applied to both ends of the capacitor C1. Further, the control circuit 13 controls the operations of the power conversion circuit 11 and the booster circuit 12 in order to supply a stable alternating voltage to the load 6.

  One end of the input AC power supply 4 is connected to the intermediate connection point of the first arm through one contact of the contactor 14, and the other end of the input AC power supply 4 is connected to the other of the reactor L <b> 1 through the other contact of the contactor 14. Is connected to the capacitor C2 side end of the output filter. Here, the capacitor C3 is a filter capacitor of the input AC power supply. Furthermore, both ends of the capacitor C <b> 2 are connected to the load 6 via the contact points of the contactor 15.

  The operation of the uninterruptible power supply 10 will be described below with reference to the waveform diagram of FIG.

  When the contactors 14 and 15 are both in the non-excited state, first, when the contactor 14 is excited, the voltage detection value of the input AC power source 4 is input to the control circuit 13 via the voltage detector PT1.

  When the input voltage of the input AC power supply 4 is healthy, the control circuit 13 forms Q1 and Q2 forming the first arm of the power conversion circuit 11 and Q5 forming the third arm as shown in FIG. , Q6 perform a switching operation in synchronization with the change in polarity of the input voltage, while Q3 and Q4 forming the second arm perform a switching operation at a frequency higher than the frequency of the input AC power supply 4, and the booster circuit 12 Is disabled (OFF state).

  In the state shown in FIG. 2 (a), when the output voltage of the power conversion circuit 11 via the voltage detector PT2, that is, the voltage across the capacitor C2, is established, the contactor 15 is excited and power supply to the load 6 is started. Is done.

  In this state, since each of Q1, Q2, Q5, and Q6 of the IGBT performs a switching operation in synchronization with the change in the voltage polarity of the input AC power supply 4, the voltage across the load 6 is the same as the voltage of the input AC power supply 4. It is almost the same. That is, as shown in FIG. 2A, the voltage fluctuation of the input AC power supply 4 also appears in the voltage across the load 6. Further, each of Q3 and Q4 of the IGBT is switched at a frequency higher than the frequency of the input AC power supply 4 so that the voltage across the capacitor C1 is maintained at a substantially constant value. In FIG. 2A, the on / off pulses of the IGBTs Q3 and Q4 are displayed at regular intervals. However, this is schematically shown, and these pulses are indicated according to the control operation in the control circuit 13. The width increases or decreases.

  In addition, when the input AC power supply 4 performing the above-described operation is in a normal state and the input AC power supply 4 is in an abnormal state and a power failure occurs, the uninterruptible power supply 10 uses the voltage detector PT1. The control circuit 13 via the control detects this and shifts the contactor 14 from the closed state to the open state as described above. At the same time, as shown in FIG. Each of the IGBTs Q5, Q6, Q3, and Q4 performs a switching operation at a high frequency while operating (OFF state), and starts the operation of the booster circuit 12, and the voltage across the capacitor C1 due to the opening operation of the contactor 14 is changed. The voltage value is maintained while suppressing the fluctuation.

  In this state, the booster circuit 12 converts the terminal voltage of the storage battery equipment 5 into a boosted DC voltage by the control circuit 13 via the voltage detector PT2, and this DC voltage changes the voltage across the capacitor C1 to a desired value. The voltage across the load 6 is made substantially equal to the rated voltage and frequency of the input AC power supply 4 by the high-frequency switching operation of the IGBTs Q3, Q4, Q5, and Q6.

  That is, at this time, the capacitor C1 is a DC power source, and an inverter circuit is formed by the second arm and the third arm of the power conversion circuit 11, thereby generating a sinusoidal AC voltage at the output of the power conversion circuit 11. be able to. In FIG. 2B, the on / off pulses of the IGBTs Q3, Q4, Q5, and Q6 are displayed at regular intervals. However, this is schematically shown and is used in the control operation of the control circuit 13. Accordingly, these pulse widths increase or decrease.

  Further, in FIG. 2B, the case where the input AC power supply 4 is in an abnormal state and is in a power failure state has been described as an example. However, the voltage of the input AC power supply 4 is within a predetermined range (for example, a rated voltage). In this uninterruptible power supply 10, even in the case of an abnormality that deviates from −12% to + 20%), the control circuit 13 via the voltage detector PT1 detects this, and the contactor 14 is opened from the closed state to the open state. While shifting to the state, the switching operation of the first to third arms and the operation of the booster circuit 12 are performed in the same manner as in the case of the power failure described above.

  According to the uninterruptible power supply apparatus 10 of the present invention, no full voltage period is required unlike the conventional power supply apparatus 1 shown in FIG. 3, and a full-scale uninterruptible power supply apparatus including a converter circuit and an inverter circuit is realized. In comparison, an inexpensive uninterruptible power supply can be provided.

Circuit configuration diagram of an uninterruptible power supply showing an embodiment of the present invention Waveform diagram explaining the operation of FIG. Circuit diagram of a power supply device showing a conventional example

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Power supply device, 2 ... Bidirectional conversion circuit, 3 ... Contactor, 4 ... Input AC power supply, 5 ... Storage battery equipment, 6 ... Load, 10 ... Uninterruptible power supply device, 11 ... Power conversion circuit, 12 ... Booster circuit, 13 ... Control circuit, 14, 15 ... Contactor, Q1-Q6 ... IGBT, L1, L2 ... Reactor, C1-C3 ... Capacitor, PT1, PT2 ... Voltage detector.

Claims (1)

A first arm, a second arm, a third arm, and a first capacitor formed by connecting two antiparallel connection circuits of a self-extinguishing semiconductor element and a diode in series are connected in parallel to each other, and one end of the first reactor Is connected to the intermediate connection point of the second arm, and the reactor side end of the output filter formed by connecting the second reactor and the second capacitor in series is connected to the intermediate connection point of the third arm. When,
Converting the terminal voltage of the storage battery equipment into a boosted DC voltage, and applying this DC voltage across the first capacitor;
One end of the input AC power source to the power conversion circuit is connected to the intermediate connection point of the first arm, and the other end of the input AC power source is connected to the other end of the first reactor and the capacitor side end of the output filter. And an uninterruptible power supply comprising a control circuit for controlling the operation of the power conversion circuit and the booster circuit to supply an AC voltage to a load connected across the second capacitor.
In the control circuit,
When the input AC power source is healthy, the first arm and the third arm perform switching operation in synchronization with the change in voltage polarity of the input AC power source, while the second arm has a frequency higher than the frequency of the input AC power source. A switching operation is performed and the booster circuit is disabled.
Further, when the input AC power supply is abnormal, the second arm and the third arm are switched at a high frequency and the booster circuit is operated while the first arm is inoperative. apparatus.

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