JP2007330072A - Synchronization control method for uninterruptible power source system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synchronization control method for an uninterruptible power source system which can self-propel with a stable output frequency of an inverter, even if the control signal is lost by constituting a synchronizing control loop for transmitting the control signal to a plurality of uninterruptible power source systems operated in parallel from an output switching board, so that the output of the inverter performs a synchronizing operation of a commercial power source or the like to be synchronized. <P>SOLUTION: The uninterruptible power source system comprises a plurality of the uninterruptible power source systems 1, 2 operated in parallel, and the output switching board 3 for switching the parallel operation output of the plurality of interruptible power source systems and a bypass power source. The output switching board outputs a first and a second frequencies corresponding to the phase difference between the bypass power source and the parallel bus lines of the plurality of uninterruptible power source systems, the plurality of uninterruptible power source systems receive the two frequencies respectively, the first frequency is added to the reference oscillator in the uninterruptible power source system, and the second frequency is deducted from the reference oscillator to obtain the output reference frequency of the inverter. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a synchronous control method when a plurality of uninterruptible power supplies are operated in parallel.

  The conventional method for synchronous control of uninterruptible power supplies is to send a synchronous control signal to a plurality of uninterruptible power supplies operating in parallel from the output switching panel, and the synchronous control signal is phase-synchronized control of each uninterruptible power supply. It is input to the circuit (for example, see Patent Document 1).

Japanese Patent Laying-Open No. 2004-357387 (page 4, FIG. 1)

  The conventional uninterruptible power supply synchronous control method is configured so that a synchronous control signal is transmitted from an output switching panel to a plurality of uninterruptible power supply units operating in parallel, and the synchronous control signal and the inverter output are synchronized. Therefore, if the signal transmitted from the output switching board is lost due to a failure of the transmitting section on the output switching board side, the output of the synchronous control signal and the inverter cannot be synchronized, of course, There is a problem that the output frequency reference of the inverter becomes unstable.

  The present invention has been made to solve the above-described problems, and from the output switching panel to the plurality of uninterruptible power supplies operating in parallel, the output of the inverter is synchronously operated on a synchronization target such as a commercial power supply. The purpose of the present invention is to provide a synchronous control method for an uninterruptible power supply capable of stably running the output frequency of an inverter even if this control signal is lost by configuring a synchronous control loop that transmits a control signal. To do.

  In the synchronous control method of the uninterruptible power supply according to the present invention, from a plurality of uninterruptible power supplies that are operated in parallel, and an output switching board that switches between parallel operation output and bypass power supply of the plurality of uninterruptible power supplies. In the configuration, the output switching board outputs the first and second frequencies corresponding to the phase difference between the bypass power supply and the parallel buses of the plurality of uninterruptible power supply units, and outputs 2 to the plurality of uninterruptible power supply units. Two frequencies are input, the first frequency is added to the reference oscillator of the uninterruptible power supply, and the second frequency is subtracted from the reference oscillator to obtain the output reference frequency of the inverter.

  According to the present invention, the parallel bus, which is the output of the inverter, can be operated synchronously with the bypass power source commercial power source to the plurality of uninterruptible power supply devices that are operating in parallel from the output switching board. Even if the control signals f1 and f2 between the output switching board and the plurality of uninterruptible power supply units are lost due to a failure of the switching board, the inverter can operate at the frequency of the reference oscillator, respectively, and at a stable output frequency. It has the effect of being able to drive on its own.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS. FIG. 1 is a system configuration diagram showing a parallel operation configuration of an uninterruptible power supply apparatus that is an object of the present invention. In the figure, 1 is a first uninterruptible power supply, and 2 is a second uninterruptible power supply. Reference numeral 101 denotes an MCCB interposed in the bypass power source, reference numeral 102 denotes an MCCB interposed between the input power source and the first uninterruptible power supply 1, and reference numeral 103 between the input power source and the second uninterruptible power source 2. MCCB 11, 14, 16 are switches that are components of the first uninterruptible power supply 1, and 12 is a converter that converts AC power that is a component of the first uninterruptible power supply 1 into DC power. , 13 is a battery which is a component of the first uninterruptible power supply 1, and 15 is an inverter which converts DC power which is a component of the first uninterruptible power supply 1 into AC power. 21, 24, 26 are switches that are components of the second uninterruptible power supply 2, 22 is a converter that converts AC power that is a component of the second uninterruptible power supply 2, and 23 is a first Reference numeral 25 denotes a battery which is a component of the uninterruptible power supply 2, and reference numeral 25 denotes an inverter which converts DC power which is a component of the second uninterruptible power supply 2 into AC power. Reference numeral 3 denotes an output switching board, which is connected to the bypass power supply and the parallel buses of the first uninterruptible power supply 1 and the second uninterruptible power supply 2. 31 and 32 are switches that are components of the output switching board 3, and the switch 31 is connected to the parallel buses of the first uninterruptible power supply 1 and the second uninterruptible power supply 2. The switch 32 is connected to a bypass power source. Reference numerals 33 and 34 denote thyristors which are components of the output switching board 3 and are connected in parallel in reverse parallel to the switch 32 to constitute a semiconductor AC switch.

  FIG. 2 is a configuration diagram showing a control circuit related to the synchronization control circuit of the output switching board 3. Reference numeral 3001 denotes a phase difference detection circuit that detects a phase difference between the bypass power supply and the parallel buses of the first uninterruptible power supply 1 and the second uninterruptible power supply 2, 3002 an amplification circuit that amplifies the phase difference signal, and 3003 Sign inverting circuits 3004 and 3005 are limiting circuits that pass only the positive side of the input signal and output zero on the negative side, and 3006 and 3007 are oscillation circuits that output a frequency proportional to the input signal.

  FIG. 3 is a configuration diagram showing a control circuit related to the synchronous control circuit of the first uninterruptible power supply 1, and the second uninterruptible power supply 2 has the same configuration although not shown. Reference numeral 1001 denotes a reference oscillator, reference numerals 1002 and 1003 denote frequency adders / subtractors for adding and subtracting frequencies, and reference numeral 1004 denotes a frequency counter, which divides the input clock frequency and applies the counter value to the inverter control circuit 1005 as a phase signal. . In FIG. 3, 15 is an inverter.

  Next, the operation will be described with reference to FIG. Usually, in the first uninterruptible power supply 1 and the second uninterruptible power supply 2, inverters 15 and 25 are operated in parallel, the switch 31 of the output switching board 3 is on, the switch 32 is off, and the thyristor 33. , 34 are off, and the outputs of the inverters 15, 25 are fed to the load. When a failure or an overload occurs and the inverters 15 and 25 cannot supply power to the load, the thyristors 33 and 34 are turned on, the switch 32 is turned on, the switch 31 is turned on, and power is supplied from the bypass power source to the load. It is necessary to synchronize the load bus and the bypass power supply so as not to give a shock to the load when the power supply is switched. Since the bypass power supply and the load bus are present in the output switching board 3, the output switching board 3, the first uninterruptible power supply 1 and the second uninterruptible power supply 2 need to perform synchronous control in cooperation. There is.

  The synchronization control method of the first embodiment will be described with reference to FIGS. First, the phase difference is obtained by the phase difference detection circuit 3001 from the bypass power supply voltage and the parallel bus voltage. This phase difference is amplified by an amplification circuit 3002 such as proportional integration. In a normal phase synchronization control circuit, this can be input to a voltage controlled oscillator and a phase control can be used to form a synchronization control loop. Here, the output switching board 3 and a plurality of uninterruptible power supply devices Since a synchronous control loop must be formed at 1 and 2, the following configuration is provided.

  When the output of the amplifier circuit 3002 is positive, the frequency f1 is transmitted to the plurality of uninterruptible power supply units 1 and 2 via the limiting circuit 3004 and the oscillation circuit 3006, respectively. When the output of the amplifier circuit 3002 is negative, the output of the sign inverting circuit 3003 is positive, and the frequency f2 via the limiting circuit 3005 and the oscillation circuit 3007 is transmitted to each of the plurality of uninterruptible power supplies. If the output of the amplifier circuit 3002 is zero, neither f1 nor f2 is output.

  On the other hand, on the uninterruptible power supply side, a control circuit is configured as shown in FIG. Although FIG. 3 shows the case of the first uninterruptible power supply 1, the second uninterruptible power supply 2 that performs parallel operation is configured in the same manner. The reference oscillator 1001 oscillates at a stable frequency f0. Reference numerals 1002 and 1003 denote frequency adder / subtracters, and the frequency of (f0 + f1−f2) is input to the counter 1004. If f1 = f2 = zero Hz, the input of the counter 1004 is f0. This f0 is frequency-divided by the counter, the phase signal θ is given to the inverter control circuit 1005, and the inverter generates a voltage at the basic frequency 50 or 60 Hz. When the basic frequency of 50 or 60 Hz must be lowered according to the frequency of the bypass power supply, the amplifier circuit 3002 outputs a negative value, f1 is zero Hz, only f2 outputs the frequency, and f0-f2 is Input to the counter 1004. Conversely, when the basic frequency of 50 or 60 Hz has to be increased depending on the frequency of the bypass power supply, the amplifier circuit 3002 outputs a positive value, f1 outputs the frequency, f2 becomes zero Hz, and f0 + f1 Is input to the counter 1004.

  Since it is configured as described above, the parallel bus that is the output of the inverter can perform synchronous operation with the bypass power supply commercial power source to the plurality of uninterruptible power supply devices that are operating in parallel from the output switching board. Of course, even if the control signals f1 and f2 between the output switching board and the plurality of uninterruptible power supply devices are lost due to a failure of the output switching board, the inverter can operate at the frequency of the reference oscillator, respectively. The self-running operation can be performed at the output frequency.

1 is a system configuration diagram showing a parallel operation configuration of an uninterruptible power supply according to Embodiment 1 of the present invention. It is a block diagram which shows the control circuit regarding the synchronous control circuit of the output switching board of the uninterruptible power supply in Embodiment 1 of this invention. It is a block diagram which shows the control circuit regarding the synchronous control circuit of the uninterruptible power supply in Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st uninterruptible power supply 2 2nd uninterruptible power supply 3 Output switching board 11, 14, 16, 21, 24, 26 Switch 12, 22 Converter 1, 23 Battery 15, 25 Inverter 31, 32 Switch 33, 34 Thyristors 101, 102, 103 MCCB
1001 Reference transmitters 1002 and 1003 Frequency adder / subtractor 1004 Frequency counter 1005 Inverter control circuit 3001 Phase difference detection circuit 3002 Amplifier circuit 3003 Sign inversion circuit 3004 and 3005 Limit circuit 3006 and 3007 Transmitter circuit

Claims (1)

In the synchronous control method of an uninterruptible power supply comprising a plurality of uninterruptible power supplies that are operated in parallel, and an output switching board that switches between a parallel operation output of the plurality of uninterruptible power supplies and a bypass power supply,
The output switching board outputs first and second frequencies corresponding to the phase difference between the bypass power supply and the parallel buses of the plurality of uninterruptible power supply units, and the two frequencies are output to the plurality of uninterruptible power supply units. The first frequency is added to the reference oscillator of the uninterruptible power supply, and the second frequency is subtracted from the reference oscillator to obtain the output reference frequency of the inverter. A method for synchronous control of a power failure power supply.

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