JP4969525B2 - Three-phase instantaneous voltage drop protection device - Google Patents

Description

  The present invention supplies three-phase AC power to a load when the voltage of the three-phase AC power supplied to the load from a three-phase AC power source such as a power system temporarily decreases or when a temporary power failure occurs. The present invention relates to a three-phase instantaneous voltage drop protection device.

  Conventionally, when the voltage of single-phase AC power supplied to a load from a 100V or 200V commercial AC power supply is reduced for a short time due to a momentary drop or the like, an instantaneous voltage drop for supplying AC power to the load instead. Protection devices are widely used (see, for example, Patent Document 1 and Non-Patent Document 1).

  The instantaneous voltage drop protection device described in the above document is a bidirectional inverter that can convert AC power supplied from an AC power supply of a power system into DC power and can also perform reverse conversion thereof, and a battery that stores energy by DC power. Capacitor, switch for switching the AC power output to the load, voltage drop of the input AC power is detected, and when the input AC power is normally supplied, it is output to the load and bidirectional When energy is stored in the capacitor via the inverter and the voltage drop of the input AC power is detected, the input AC power and the load are separated by the switch, and the DC power based on the electric energy stored in the capacitor for storage is bidirectional inverter. And a control unit that converts the power into AC power and outputs the AC power to a load.

  In general, single-phase AC power is often used, but factories and the like often use three-phase AC power in addition to single-phase AC power. For this reason, although there is a demand for an instantaneous voltage drop protection device for a three-phase AC power supply, the price of an instantaneous voltage drop protection device for a three-phase AC power supply is generally for a single-phase AC power supply having a comparable rated capacity. Compared to the instantaneous voltage drop protection device, it is quite expensive. The main reason is that the instantaneous voltage drop protection device for three-phase AC power supply is less demanding than the instantaneous voltage drop protection device for single-phase AC power supply, so there is almost no cost merit due to mass production in production. This is because there are cost increase factors for order production and small-volume production. In addition, the product lineup of instantaneous voltage drop protection devices for three-phase AC power supplies is smaller than that of single-phase AC power supply instantaneous voltage drop protection devices. There is also a reason that it is often necessary to purchase an expensive device having a considerably large rated capacity compared to the output capacity.

JP 2008-54468 A “Expert KDPseries of instantaneous drop protection device”, [online], Kyoto Denki Co., Ltd. [searched July 7, 2008], Internet <URL: http://www.kdn.co.jp/kdp/lineup .html>

  That is, from the viewpoint of the manufacturer of the instantaneous voltage drop protection device, the demand for the instantaneous voltage drop protection device for the three-phase AC power supply is low, and there is almost no merit to manufacture it with an estimated order, so the product price must be raised. Absent. In addition, it is difficult to make a product lineup even if it is made to order. On the other hand, from the user's point of view, the instantaneous voltage drop protection device for a three-phase AC power supply is more expensive than the single-phase AC power supply instantaneous voltage drop protection device, and there is a great dissatisfaction that it takes time to obtain.

  The present invention has been made to solve these problems, and the object of the present invention is to provide instantaneous voltage drop protection for a three-phase that can be obtained by a user at a lower cost and with a shorter delivery time than conventional ones. To provide an apparatus.

  In view of the above problems, the inventor of the present application uses the basic circuit of the single-phase instantaneous voltage drop protection device almost as it is, which is in constant demand and easily exhibits the cost reduction effect by mass production. The idea was to realize a three-phase instantaneous voltage drop protection function by adding additional hardware and software.

That is, the present invention, which has been made to solve the above-mentioned problems, is inserted between a three-phase AC power supply and a load, and an instantaneous voltage drop or an instantaneous voltage interruption of the three-phase AC power supplied from the three-phase AC power supply. In the three-phase instantaneous voltage drop protection device that temporarily supplies three-phase AC power to the load when
a) an input terminal to which AC power of the first phase and the second phase of the three-phase AC power source is input; power storage means for storing electric energy based on the AC power supplied to the input terminal; Inverter means for converting the supplied AC power to DC power to charge the power storage means, and when the AC voltage supplied to the input terminal is temporarily reduced, it is stored in the power storage means instead. A first single-phase instantaneous voltage drop protection circuit unit having control means for executing an instantaneous voltage drop protection operation by converting the electric energy being converted into alternating current power by the inverter means and supplying the converted electric energy to the outside,
b) Second phase instantaneous power supply having the same configuration as that of the first single phase instantaneous voltage drop protection circuit section, in which the second phase and third phase AC power of the three-phase AC power supply is input to the input terminal. Voltage drop protection circuit,
c) a voltage drop detecting means for detecting a voltage drop of the AC power between the first phase and the third phase of the three-phase AC power line;
d) whether a voltage drop is detected by the voltage drop detection means, or whether a voltage drop of the AC power between the first phase and the second phase is detected in the first single-phase instantaneous voltage drop protection circuit unit; Alternatively, when either of the second single-phase instantaneous voltage drop protection circuit section detects a voltage drop of the AC power between the second phase and the third phase, the instantaneous voltage drop protection operation Cooperating command means for giving a command to the control means to start the instantaneous voltage drop protection operation for one or both of the first or second single-phase instantaneous voltage drop protection circuit units that are not executing
e) Each phase of the three-phase AC power output when both the first and second single-phase instantaneous voltage drop protection circuit units execute the instantaneous voltage drop protection operation according to the command from the cooperation command means. Phase adjusting means for adjusting the phase of
It is characterized by having.

  In the three-phase instantaneous voltage drop protection device according to the present invention, the first and second single-phase instantaneous voltage drop protection circuit units detect the instantaneous voltage drop protection when detecting the voltage drop of the AC power supplied to the input terminals, respectively. The operation is executed, and instead of the AC power supplied to the input terminal, AC power based on the electrical energy stored in the power storage means is output. However, in the case of a three-phase AC power supply, a voltage drop of only one of the phases may occur. For example, the first single-phase instantaneous voltage drop protection circuit unit detects a voltage drop. In such a single-phase instantaneous voltage drop protection circuit unit, there may be a situation where no voltage drop is detected. In addition, there may be a situation where the voltage drop of the AC power between the first phase and the third phase is not detected by any of the first and second single-phase instantaneous voltage drop protection circuit units.

  Therefore, in order to compensate for the leakage of the voltage drop detection as described above, the voltage drop detection means detects the voltage drop of the AC power between the first phase and the third phase of the three-phase AC power supply line. The cooperating command means monitors whether or not the voltage drop is detected in the first and second single-phase instantaneous voltage drop protection circuit units, and whether or not the voltage drop is detected in the voltage drop detection means, and a voltage drop is detected. If so, the instantaneous voltage drop protection operation is started for one or both of the first or second single-phase instantaneous voltage drop protection circuit units not executing the instantaneous voltage drop protection operation. For example, when a voltage drop is detected in the first single-phase instantaneous voltage drop protection circuit unit, an instantaneous voltage drop protection operation is started as a function of the circuit unit, and the other second single-phase instantaneous voltage drop protection operation is started. The circuit unit starts the instantaneous voltage drop protection operation based on the command from the cooperation command means. Thereby, regardless of the voltage drop in any state, the first and second single-phase instantaneous voltage drop protection circuit units both perform the instantaneous voltage drop protection operation.

  Further, when both the first and second single-phase instantaneous voltage drop protection circuit units execute the instantaneous voltage drop protection operation, the phase relationship between the voltages of the three phases of the output three-phase AC power is as specified (for example, When the S phase is used as a reference, the R phase needs to be advanced by 120 ° and the T phase must be advanced by 120 °. Therefore, the phase adjustment means determines the phase of each phase of the three-phase AC power that is output when both the first and second single-phase instantaneous voltage drop protection circuit units execute the instantaneous voltage drop protection operation. Adjust and synchronize the voltage of each phase so that the phase is as specified. Specifically, a reference synchronization signal having, for example, an S-phase is provided, and phase adjustment is performed so that the other two-phase voltages are 120 ° ahead and 120 ° behind. be able to.

  In the three-phase instantaneous voltage drop protection device according to the present invention, an inverter means and a power storage means, which are main hardware for executing the instantaneous voltage drop protection operation, are developed and manufactured for single-phase AC power supplies. Since it can be used as it is, it is easy to demonstrate cost merit due to mass production effects. On the other hand, the components to be added for the three-phase AC power supply, such as the voltage drop detection means, the cooperation command means, and the phase adjustment means, are mainly composed of a microcontroller including a CUP, and the software Although it needs to be developed, the hardware is relatively simple and it is easy to keep costs down. Therefore, according to the three-phase instantaneous voltage drop protection device according to the present invention, it is possible to provide a user with an inexpensive device as compared with the conventional device. In addition, because it can be manufactured based on the single-phase instantaneous voltage drop device that is in constant demand, the delivery time until the device is supplied to the user can be shortened, and the manufacturer avoids missing business opportunities. can do.

  In addition, as an embodiment of the three-phase instantaneous voltage drop protection device according to the present invention, all may be configured to be housed in a single housing, but the single-phase instantaneous voltage drop protection circuit unit is configured as a single single-phase instantaneous voltage drop protection circuit unit. When considering the merit that can be provided as a voltage drop protection device, the first and second single-phase instantaneous voltage drop protection circuit units are housed in separate cases, respectively, the voltage drop detection means, the cooperation command means, And the said phase adjustment means is good to set it as the structure accommodated in another one housing | casing. This is more effective in reducing the cost and shortening the delivery time of the three-phase instantaneous voltage drop protection device.

  An embodiment of a three-phase instantaneous voltage drop protection device according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic block diagram of a three-phase instantaneous voltage drop protection device according to this embodiment.

  The three-phase instantaneous voltage drop protection device 1 of the present embodiment has two basic single-phase instantaneous voltage drop protection devices (first and second single-phase instantaneous voltage drop protection circuit units in the present invention) as a basic configuration. 3 and 4 and a three-phase interface (I / F) unit 2.

  R-phase, S-phase, and T-phase three-phase AC power supplied from the three-phase AC power source 100 of the power supply system is input to the three-phase instantaneous voltage drop protection device 1, and the R-phase and S-phase AC power is included. The S-phase and T-phase AC power is input to the power input terminal 30 of the second single-phase instantaneous voltage drop protection device 4, and R Phase, S-phase, and T-phase AC power is input to the power input terminal 24 of the three-phase interface unit 2. Further, from the power output terminal 33 of the first single-phase instantaneous voltage drop protection device 3 and the power output terminal 33 of the second single-phase instantaneous voltage drop protection device 4, a three-phase alternating current of R phase, S phase, and T phase. Electric power is output and supplied to a load (not shown). In addition to the AC power supply line described above, the control signal terminal 47 of the first single-phase instantaneous voltage drop protection device 3 and the control signal terminal 25 of the three-phase interface unit 2 are mutually connected by a control line. The control signal terminal 47 of the second single-phase instantaneous voltage drop protection device 4 and the control signal terminal 26 of the three-phase interface unit 2 are also connected to each other by a control line.

  The first and second single-phase instantaneous voltage drop protection devices 3 and 4 basically have the same circuit configuration. FIG. 3 is a schematic configuration diagram of the single-phase instantaneous voltage drop protection devices 3 and 4. The basic circuit configuration disclosed in Patent Document 1 can be used.

  In FIG. 3, the AC power supplied to the power input terminal 30 is output to the power output terminal 33 via a switching unit 31 in which an FET switch 311 and an overcurrent protection bidirectional thyristor 312 are connected in parallel. Further, the AC power is input to the inverter unit 35 including a plurality of switching elements. The FET switch 311 and the bidirectional thyristor 312 are independently controlled to be turned on / off by a drive signal supplied from the switching drive unit 44.

  The inverter unit 35 is connected to an electrolytic capacitor 36 as a power storage means. The inverter unit 35 converts AC power into DC to charge the electrolytic capacitor 36, or conversely, the electric energy held in the electrolytic capacitor 36 is converted. It has a bidirectional function for DC / AC conversion. In the latter case, the high frequency component superimposed on the AC power is removed by the filter 34 including an inductance and a capacitor. Further, in order to charge the electrolytic capacitor 36, a supplementary charging unit 37 is separately provided. The auxiliary charging unit 37 includes a transformer 371, a bidirectional thyristor 372 connected in series to the primary winding of the transformer 371, a rectifying diode 373 connected to the secondary winding of the transformer 371, a capacitor 374, a resistor 375, and the like. The electrolytic capacitor 36 including can be charged from both the inverter unit 35 and the auxiliary charging unit 37. The bidirectional thyristor 372 of the auxiliary charging unit 37 is controlled to be turned on / off by a drive signal given by the auxiliary charging drive unit 41. Each switching element of the inverter unit 35 is controlled to be turned on / off by a drive signal given by the inverter drive unit 43.

  The voltage drop detection unit 40 monitors the voltage drop of the AC power applied to the power input terminal 30 and immediately notifies the control unit 46 of the voltage drop detection. The charging voltage detection unit 42 detects the charging voltage held in the electrolytic capacitor 36 and inputs the voltage value to the control unit 46. Further, the load current output from this apparatus is detected by the current transformer 32 and the load current detection unit 45, and the current value is input to the control unit 46. The control unit 46 is mainly configured by a CPU or the like, and executes various controls and processes for the instantaneous voltage drop protection operation according to a preset program.

  The basic operation of the single-phase instantaneous voltage drop protection devices 3 and 4 will be schematically described. When the voltage of the AC power supplied to the power input terminal 30 is normal, the FET switch 311 of the switching unit 31 is turned on, and the input AC power is supplied to the power output terminal 33. At this time, the electrolytic capacitor 36 is charged based on the AC power as described later, and electric energy is stored in the electrolytic capacitor 36. When the voltage of the input AC power temporarily decreases, the control unit 46 recognizes the voltage decrease by the detection signal from the voltage decrease detection unit 40 and turns off the FET switch 311 of the switching unit 31 via the switching drive unit 44. The power output terminal 33 and the power input terminal 30 are disconnected.

  At the same time, the inverter 35 is operated by the inverter drive unit 43, the voltage held in the electrolytic capacitor 36 until just before that is DC / AC converted, the waveform is shaped via the filter 34, and the power output terminal 33 is used as compensation power. To supply. When the voltage drop of the AC power input to the power input terminal 30 is resolved, the control unit 46 stops the operation of the inverter unit 35 to stop the supply of compensation power, and then promptly inputs the power by the switching unit 31. The end 30 and the power output end 33 are connected, and input AC power is output from the power output end 33.

  For example, when the electric energy of the electrolytic capacitor 36 is greatly reduced by the discharging operation, it is necessary to charge the electrolytic capacitor 36 rapidly in preparation for the next instantaneous voltage drop. Therefore, when the charging voltage is lower than a predetermined value, the inverter unit 35 is operated, and the supplied AC power is converted to DC power to charge the electrolytic capacitor 36 rapidly. On the other hand, when the charging voltage reaches the rated voltage and then gradually decreases due to natural discharge to a specified value, the auxiliary charging unit 37 is operated instead of the inverter unit 35 to compensate for the reduced voltage. Charge the battery. As a result, the inverter unit 35 can be hardly operated during normal times (when the input AC power is normal), and generation of noise due to frequent operation of the inverter unit 35 can be avoided.

  As described above, when a voltage drop is detected by the voltage drop detection unit 40 and an instantaneous current drop protection operation is performed, a voltage drop detection signal is output to the control signal terminal 47. On the other hand, when a compulsory operation command is given to the control signal terminal 47 in addition to the detection of the own voltage drop, the control unit 46 executes the instantaneous voltage drop protection operation regardless of whether or not the own voltage drop is detected. Further, a reference signal having the same frequency (50 Hz or 60 Hz) as the AC voltage is input to one of the control signal terminals 47 as a phase synchronization signal. When the AC power is normal, this phase synchronization signal is stored as a phase difference, and during the instantaneous voltage drop protection operation, the AC voltage having the same phase as this phase synchronization signal is set to S phase, and the R phase AC voltage output is It is assumed that the phase is advanced by 120 ° from the phase synchronization signal, and the phase of the T-phase AC voltage output is adjusted so that the phase is delayed by 120 ° from the phase synchronization signal.

  FIG. 2 is a schematic configuration diagram of the three-phase interface unit 2. The three-phase interface unit 2 includes a voltage drop detection unit 21, a synchronization signal generation unit 22, and a control unit 23. The voltage drop detection unit 21 monitors a voltage between the R-phase input and the S-phase input and a voltage between the S-phase input and the T-phase input to generate a pseudo R-phase-T phase voltage, This drop in voltage is detected. The control unit 23 outputs two control signal terminals 47 of the first and second single-phase instantaneous voltage drop protection devices 3 and 4 to the control signal terminals 25 and 26 through control lines. That is, a voltage drop detection signal between the R phase and the S phase and between the S phase and the T phase, and a voltage drop detection signal between the S phase and the T phase by the internal voltage drop detection unit 21 are input. When a voltage drop is recognized by any one of these three voltage drop detection signals, the control unit 23 controls the control signal for one or both of the single-phase instantaneous voltage drop protection devices 3 and 4 in which no voltage drop is detected. An operation command is sent from the terminals 25 and 26.

  On the other hand, the synchronization signal generator 22 generates a phase synchronization signal synchronized with the phase of the S phase input, and even if the S phase input is lowered, the phase synchronization signal synchronized with the previous S phase input is supplied to the control signal terminal 25. , 26 continues to be output. By matching the phases of the other phases as described above with reference to this, the phase of the three-phase AC power output as the compensation voltage when the voltage is lowered can be made as specified.

  An example of a specific operation of the instantaneous voltage drop protection device of this embodiment will be described. It is assumed that, for example, the voltage between the R phase and the S phase is abnormally lowered from the state in which the three-phase AC power is normally supplied from the three-phase AC power source 100. At this time, in the first single-phase instantaneous voltage drop protection device 3, the voltage drop detection unit 40 detects the voltage drop, and the instantaneous voltage drop protection operation is executed under the control of the control unit 46, so that the electrolytic capacitor 36 A compensated AC voltage based on the stored electrical energy is output to the power output terminal 33. At this time, the R-phase AC voltage has a waveform that is 120 ° ahead of the phase synchronization signal, and the S-phase AC voltage has the same phase as that of the phase synchronization signal.

  Almost simultaneously with the start of the instantaneous voltage drop protection operation, a voltage drop detection signal is sent from the first single-phase instantaneous voltage drop protection device 3 to the three-phase interface unit 2, and the control unit 23 receives the second voltage drop detection signal. An operation command is sent to the single-phase instantaneous voltage drop protection device 4. In the second single-phase instantaneous voltage drop protection device 4 that has received the operation command, the control unit 46 operates the inverter unit 35 so that the compensated AC voltage based on the electrical energy accumulated in the electrolytic capacitor 36 is supplied to the power output terminal 33. To output. At this time, the T-phase AC voltage has a waveform that is 120 ° behind the phase synchronization signal, and the S-phase AC voltage has the same phase as that of the phase synchronization signal.

  As described above, in the three-phase instantaneous voltage drop protection device 1 according to the present embodiment, the three-phase AC power is continuously supplied to the load in place of the three-phase AC power supply 100 whose voltage is temporarily reduced or is blacked out. Can do. Further, when the voltage between the T phase and the S phase is abnormally reduced, the voltage drop detecting unit 40 detects the voltage drop in the second single-phase instantaneous voltage drop protection device 4, and the instantaneous voltage drop protection operation is started. The first single-phase instantaneous voltage drop protection device 3 receives an operation command from the three-phase interface unit 2 and starts an instantaneous voltage drop protection operation. When the S-phase to T-phase voltage drops abnormally, the voltage drop detecting unit 21 first detects a voltage drop in the three-phase interface unit 2, and the first and first phases are detected according to the operation command issued from the control unit 23. 2 The single-phase instantaneous voltage drop protection devices 3 and 4 start the instantaneous voltage drop protection operation.

  FIG. 4 is an external view showing an example of the form of the three-phase instantaneous voltage drop protection device 1 of the present embodiment. The single-phase instantaneous voltage drop protection devices 3 and 4 can each be used alone for instantaneous voltage drop protection of a single-phase AC power supply. Therefore, in the example shown in FIG. 4, the single-phase instantaneous voltage drop protection devices 3 and 4 can be used as independent devices housed in a casing, and another casing having substantially the same width and depth as this. The three-phase interface unit 2 is housed in the body, and the appearance is uniform when three units are stacked. Wiring such as a power supply line and a control line can be performed between connectors provided on the back side of each case, but when stacked as shown in FIG. 4, the bottom surface of the upper case and the lower case are connected. A connector that allows mutual connection with the top surface may be provided separately.

  The above-described embodiment is an example of the present invention, and it is a matter of course that modifications, corrections, and additions may be appropriately made within the scope of the present invention, and included in the scope of the claims of the present application.

1 is a schematic block diagram of a three-phase instantaneous voltage drop protection device according to an embodiment of the present invention. The schematic block diagram of the interface part for three phases in FIG. The schematic block diagram of the instantaneous voltage drop protection device for single phases in FIG. The external view which shows an example of the form of the instantaneous voltage drop protection apparatus for three phases of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Three-phase instantaneous voltage drop protective device 100 ... Three-phase alternating current power supply 2 ... Three-phase interface part 21 ... Voltage drop detection part 22 ... Synchronous signal generation part 23 ... Control part 24 ... Power input terminal 25, 26 ... Control Signal terminals 3, 4 ... Single-phase instantaneous voltage drop protection device 30 ... Power input 31 ... Switching unit 311 ... FET switch 312 ... Bidirectional thyristor 32 ... Current transformer 33 ... Power output 34 ... Filter 35 ... Inverter unit 36 ... Electrolytic capacitor 37 ... auxiliary charging unit 371 ... transformer 372 ... bidirectional thyristor 373 ... rectifier diode 374 ... capacitor 375 ... resistor 40 ... voltage drop detecting unit 41 ... auxiliary charging driving unit 42 ... charging voltage detecting unit 43 ... inverter driving unit 44 ... switching drive unit 45 ... load current detection unit 46 ... control unit 47 ... control signal terminal

Claims (2)

When the instantaneous voltage drop or instantaneous voltage interruption of the three-phase AC power supplied from the three-phase AC power supply is inserted between the three-phase AC power supply and the load, the three-phase AC power is temporarily supplied to the load. In the three-phase instantaneous voltage drop protection device
a) an input terminal to which AC power of the first phase and the second phase of the three-phase AC power source is input; power storage means for storing electric energy based on the AC power supplied to the input terminal; Inverter means for converting the supplied AC power to DC power to charge the power storage means, and when the AC voltage supplied to the input terminal is temporarily reduced, it is stored in the power storage means instead. A first single-phase instantaneous voltage drop protection circuit unit having control means for executing an instantaneous voltage drop protection operation by converting the electric energy being converted into alternating current power by the inverter means and supplying the converted electric energy to the outside,
b) Second phase instantaneous power supply having the same configuration as that of the first single phase instantaneous voltage drop protection circuit section, in which the second phase and third phase AC power of the three-phase AC power supply is input to the input terminal. Voltage drop protection circuit,
c) a voltage drop detecting means for detecting a voltage drop of the AC power between the first phase and the third phase of the three-phase AC power line;
d) whether a voltage drop is detected by the voltage drop detection means, or whether a voltage drop of the AC power between the first phase and the second phase is detected in the first single-phase instantaneous voltage drop protection circuit unit; Alternatively, when either of the second single-phase instantaneous voltage drop protection circuit section detects a voltage drop of the AC power between the second phase and the third phase, the instantaneous voltage drop protection operation Cooperating command means for giving a command to the control means to start the instantaneous voltage drop protection operation for one or both of the first or second single-phase instantaneous voltage drop protection circuit units that are not executing
e) Each phase of the three-phase AC power output when both the first and second single-phase instantaneous voltage drop protection circuit units execute the instantaneous voltage drop protection operation according to the command from the cooperation command means. Phase adjusting means for adjusting the phase of
A three-phase instantaneous voltage drop protection device comprising: The three-phase instantaneous voltage drop protection device according to claim 1,
The first and second single-phase instantaneous voltage drop protection circuit units are housed in separate cases, respectively, and the voltage drop detection means, the cooperation command means, and the phase adjustment means are provided in another case. A three-phase instantaneous voltage drop protection device characterized by being housed in a body.

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