JP4332688B2 - 3-phase input / 1-phase output power converter, 3-phase input / 3-phase output PWM cycloconverter and 3-phase output multiplex type PWM cycloconverter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power converter that converts AC power of an AC power source into AC power of an arbitrary frequency, and more particularly to a pulse width modulation (hereinafter referred to as PWM) cycloconverter type power converter.
[0002]
[Prior art]
Conventionally, a PWM cycloconverter is known as a power conversion device that converts AC power output from an AC power source into AC power having an arbitrary frequency.
[0003]
A PWM cycloconverter is configured by using at least one self-quenching switching element such as an insulated gate bipolar transistor (hereinafter referred to as IGBT) and a diode, and allows a plurality of currents to flow bidirectionally from input to output or vice versa. The bi-directional switch is driven by PWM control to output AC power having an arbitrary frequency.
[0004]
FIG. 6 is a block diagram showing a configuration of a conventional 3-phase input / 3-phase output PWM cyclo inverter. The three-phase power source 1 is connected to the bidirectional switch group 3 via the input filter 2, and the bidirectional switch group 3 is connected to the induction motor 4.
[0005]
The bidirectional switch group 3 includes nine bidirectional switches 11 to 19. The output R of the three-phase power source 1 is input to the bidirectional switches 11, 14, and 17, and the output S of the three-phase power source 1 is input to the bidirectional switches 12, 15, and 18, and the output T of the three-phase power source 1 is Are input to the bidirectional switches 13, 16 and 19.
[0006]
Further, the outputs of the bidirectional switches 11, 12, 13 become the input U to the induction motor 4, and the outputs of the bidirectional switches 14, 15, 16 become the input V to the induction motor 4, and the bidirectional switches 17, 18. , 19 becomes the input W to the induction motor 4.
[0007]
The bidirectional switches 11 to 19 have a circuit configuration shown in FIG. 7 (a) or FIG. 7 (b). The bidirectional switch shown in FIG. 7A includes a unidirectional switch composed of an IGBT 31 and a diode 33, and a unidirectional switch composed of an IGBT 32 and a diode 34. The cathode terminal of the diode 33 is connected to the collector terminal of the IGBT 31, and the anode terminal of the diode 33 is connected to the emitter terminal of the IGBT 31. The cathode terminal of the diode 34 is connected to the collector terminal of the IGBT 32, and the anode terminal of the diode 34 is connected to the emitter terminal of the IGBT 32. The emitters of the IGBT 31 and IGBT 32 are connected to each other to form a bidirectional switch.
[0008]
The bidirectional switch shown in FIG. 7B is formed by a unidirectional switch composed of an IGBT 31 and a diode 33, and a unidirectional switch composed of an IGBT 32 and a diode 34. The cathode terminal of the diode 33 is connected to the collector terminal of the IGBT 31 to form a one-way switch, and the cathode terminal of the diode 34 is connected to the collector terminal of the IGBT 32 to form the other one-way switch. In addition, the emitter terminal of the IGBT 32 and the anode terminal of the diode 33 are connected, the emitter terminal of the IGBT 31 and the anode terminal of the diode 34 are connected, and the one-way switches are connected in antiparallel to form a bidirectional switch. The
[0009]
The IGBT 31 and the IGBT 32 require a drive circuit that drives a gate signal input to them. In addition, a power supply for supplying power to these drive circuits is required. Since this power source must be insulated from other power sources, insulated power sources that are insulated from each other are used.
[0010]
FIG. 8 shows a state of connection between one IGBT and a drive circuit, which is a drive circuit for driving the IGBT, and an insulated power supply. The gate terminal G1 of the IGBT 40 is connected to the drive circuit D1, and the power of the drive circuit D1 is supplied from the insulated power supply PS1. The ground terminal PSG1 of the insulated power supply PS1 is connected to the emitter terminal E1 of the IGBT and the ground terminal DG1 of the drive circuit.
[0011]
As shown in FIG. 8, one drive circuit and one drive circuit insulated power supply are required for each IGBT. The power converter of FIG. 6 has 18 switching elements. For this reason, 18 drive circuits for driving the element are required, and 18 insulated power supplies for the drive circuit are also required.
[0012]
Further, in the PWM cycloconverter as described above, bidirectional switches are multiplexed by adjusting the voltage and current supplied to the induction motor 4 in series or in parallel. Sometimes. In the PWM cycloconverter in which the bidirectional switch is multiplexed, it is necessary to redesign the parts related to the drive circuit and the insulated power source according to the connection form.
[0013]
[Problems to be solved by the invention]
The conventional PWM cycloconverter has the following two problems.
(1) When the circuit configuration is changed in order to multiplex bidirectional switches, it is necessary to redesign the parts related to the drive circuit and the insulated power supply circuit each time, so that the time required for circuit design and manufacturing increases. To do.
(2) Since the number of the isolated power supplies for the drive circuit for driving the bidirectional switch is the same as the number of self-extinguishing switches constituting the bidirectional switch, the entire PWM cycloconverter is increased in size.
[0014]
Therefore, the present invention can change the configuration of the PWM cycloconverter without changing the design around the drive circuit and the isolated power supply even when the configuration of the PWM cycloconverter is changed to multiplex the bidirectional switch group. It aims at providing the power converter device which can be performed.
[0015]
A further object of the present invention is to provide a power conversion device that can reduce the size of a PWM cycloconverter by using a common insulated power supply.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, the power conversion device of the present invention includes three input terminals for inputting AC power of a three-phase AC power source for each phase, and one output for outputting one-phase AC of an arbitrary frequency . A bidirectional switch group in which a bidirectional switch formed by combining an output terminal and two one-way switches in opposite directions is inserted between each of the input terminals and the output terminal; As one device having a drive circuit group provided with a drive circuit for driving the unidirectional switch for each of the unidirectional switches , and an insulated power supply group provided with a plurality of insulated power supplies for supplying power to the respective drive circuits. Is configured .
[0017]
The power conversion device of the present invention includes a bidirectional switch, a drive circuit necessary for driving the bidirectional switch, and an insulated power supply, and is designed as a PWM cycloconverter with three-phase input / three-phase output. In this case, it is not necessary to change the design around the drive circuit and the power supply circuit even when the configuration of the PWM cycloconverter is changed by combining the power conversion device of the present invention. Manufacturing time is reduced.
[0018]
In another power converter of the present invention, each bidirectional switch is configured based on two IGBTs connected in opposite directions, and a drive circuit that drives the one-way switch drives the IGBT. The three IGBT emitters constituting each one-way switch connected from each input terminal to the output terminal are connected in common to the output terminal, and power is supplied to each drive circuit of the IGBT. Insulated power supply is shared .
[0019]
In the power conversion device according to the present invention, the number of insulated power supplies is reduced from six conventionally required to four by sharing the common insulated power supply with each drive circuit that drives each IGBT whose emitter terminals are connected to each other. Therefore, it is possible to reduce the size of the PWM cycloconverter.
[0020]
In another power converter of the present invention, each bidirectional switch is configured based on two IGBTs connected in opposite directions, and a drive circuit that drives the one-way switch drives the IGBT. In the IGBT, the two IGBTs constituting each bidirectional switch are commonly connected to each other, and the insulated power supply for supplying power to each drive circuit of the IGBT is shared .
[0021]
In the power conversion device of the present invention, the emitter terminals of IGBTs constituting one bidirectional switch are connected to each other, and the emitter terminals are equipotential. Therefore, the insulated power supply for supplying electric power to the two drive circuits that drive each IGBT constituting one bidirectional switch is made common. Therefore, the number of insulated power supplies becomes three, and the PWM cycloconverter can be further downsized by reducing the number of insulated power supplies from four to three.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described in detail with reference to the drawings. In all the drawings, the constituent elements having the same reference numerals are all the same constituent elements.
[0023]
FIG. 1 is a circuit diagram showing a configuration of the power conversion device of the present embodiment. The power conversion device of this embodiment includes a bidirectional switch group 300, a drive circuit group 800, and an insulated power supply group 700.
[0024]
The bidirectional switch group 300 includes three bidirectional switches 301, 401, and 501, and includes input terminals 610, 611, and 612 connected to the three-phase power supply 1 and an output terminal 600. One end of each of the three bidirectional switches 301, 401, and 501 is connected to the three input terminals 610, 611, and 612, and the other end is connected to the output terminal 600.
[0025]
The bidirectional switch 301 is composed of two IGBTs 311 and 321 and two diodes 331 and 341. The bidirectional switch 401 is composed of two IGBTs 411 and 421 and two diodes 431 and 441. The bidirectional switch 501 is composed of two IGBTs 511 and 521 and two diodes 531 and 541. The connection form of the bidirectional switches 301, 401, and 501 is the same connection form as FIG.
[0026]
The drive circuit group 800 includes six drive circuits 801, 802, 803, 811, 812, 813. Drive circuits 801 to 803 and 811 to 813 are connected to gate terminals of IGBTs 311, 411, 511, 321, 421 and 521, respectively.
[0027]
The insulated power supply group 700 is composed of four insulated power supplies 701 to 704. The power supply terminal PN2 and the ground terminal GND2 are connected to the drive circuit 801, and the insulated power supply 702 supplies power to the drive circuit 801. The ground terminal GND2 is also connected to the emitter terminal of the IGBT 311.
[0028]
The power supply terminal PN3 and the ground terminal GND3 are connected to the drive circuit 802, and the insulated power supply 703 supplies power to the drive circuit 802. The ground terminal GND3 is also connected to the emitter terminal of the IGBT 411.
The power supply terminal PN4 and the ground terminal GND4 are connected to the drive circuit 802, and the insulated power supply 704 supplies power to the drive circuit 803. The ground terminal GND4 is also connected to the emitter terminal of the IGBT 511.
[0029]
The emitter terminal of the IGBT 321, the emitter terminal of the IGBT 421, and the emitter terminal of the IGBT 521 are connected to each other and are always equipotential. , 813 can be shared. Accordingly, the power supply terminal PN1 and the ground terminal GND1 are connected to the drive circuits 811, 812, 813, and the insulated power supply 701 supplies power to the drive circuits 811, 812, 813. The ground terminal GND <b> 1 is also connected to the IGBT 321, the IGBT 421, and the emitter terminal of the IGBT 521.
[0030]
In the power conversion device of this embodiment, the drive circuits 811, 812, and 813 share the same insulated power supply 701, so that the number of insulated power supplies can be reduced from the originally required six to four.
[0031]
Next, the configuration of a PWM cycloconverter using the power conversion device of this embodiment will be described. FIG. 2 is a block diagram showing a configuration of a three-phase input / three-phase output PWM cycloconverter using the power conversion device of the present embodiment.
[0032]
The PWM cycloconverter is configured by combining three power converters 5 of this embodiment. By designing a PWM cycloconverter with a bidirectional switch, a drive circuit necessary for driving the bidirectional switch, and a power conversion device 5 including the drive circuit, a part related to the drive circuit and the isolated power supply is designed. Since there is no need for correction, the circuit design of the PWM cycloconverter with three-phase input / three-phase output is facilitated.
[0033]
Further, the power conversion device of this embodiment can also be applied to a multiplex type PWM cycloconverter. FIG. 3 is a block diagram showing a configuration of a serial multiplex type PWM cycloconverter using the power conversion device of one embodiment of the present invention.
[0034]
Such a serial multiplex type PWM cycloconverter connects the power conversion device 5 in series when the induction motor 4 requires a voltage larger than the voltage output from the power conversion device 5, and the voltage to the induction motor 4. Configured to increase
[0035]
Further, the serial multiplex type PWM cycloconverter can make the waveform of the current input to the induction motor 4 closer to a sine wave by multiplexing the power converter 5 in series, and the harmonics included in the current can be reduced. Can be suppressed.
[0036]
FIG. 4 is a block diagram showing a configuration of a parallel multiplex type PWM cycloconverter using the power conversion device of one embodiment of the present invention. Such a parallel multiplex type PWM cycloconverter connects the power converter 5 in parallel when the value of the current required by the induction motor 4 is larger than the current output from one power converter 5, and the induction motor 4 to increase the input current to 4.
[0037]
In any case of FIG. 3 and FIG. 4, the circuit design of the multiplex type PWM cycloconverter can be easily performed by combining the power conversion device 5 of the present embodiment.
[0038]
In the power conversion device of this embodiment, the circuit configuration of the bidirectional switch is equivalent to the circuit configuration of FIG. 7B, but the circuit configuration of the bidirectional switch is equivalent to the circuit configuration of FIG. It may be.
[0039]
FIG. 5 is a circuit diagram showing the configuration of the power converter when the circuit configuration of the bidirectional switch is equivalent to that of FIG. The circuit configuration of the power conversion device is almost the same as the circuit configuration of the power conversion device in FIG. 1, but instead of the bidirectional switches 301, 401, and 501, the circuit configuration equivalent to the circuit configuration in FIG. Bidirectional switches 351, 451, 551 are inserted between the input terminals 610, 611, 612 and the output terminal 600.
[0040]
In this power converter, the IGBT emitter terminals constituting one bidirectional switch are connected to each other, and the connected emitter terminals are equipotential. Therefore, it is possible to share an insulating power source that supplies power to the two drive circuits that drive each IGBT constituting one bidirectional switch. Therefore, the number of insulated power supplies required for this power converter is three. That is, if the circuit configuration of the bidirectional switch is as shown in FIG. 7A, the number of insulated power supplies can be reduced by one as compared with the configuration as shown in FIG. 7B.
[0041]
1 and FIG. 5, IGBTs and diodes are used. For these, other self-extinguishing switches having a reverse withstand voltage such as a gate turn-off thyristor (GTO) are used. It may be used instead.
[0042]
【The invention's effect】
As described above, by configuring the PWM cycloconverter with the power conversion device of the present invention, the circuit design and manufacture of the PWM cycloconverter can be simplified, and the time required for these processes can be shortened.
[0043]
In addition, the PWM converter can be miniaturized by the power conversion device of the present invention.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a configuration of a power conversion device according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a three-phase input / three-phase output PWM cycloconverter using the power conversion device of one embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration of a serial multiplex type PWM cycloconverter using the power converter of one embodiment of the present invention.
FIG. 4 is a block diagram showing a configuration of a parallel multiplex type PWM cycloconverter using the power conversion device of one embodiment of the present invention.
FIG. 5 is a circuit diagram showing a configuration of a power conversion device according to another embodiment of the present invention.
FIG. 6 is a block diagram showing a configuration of a conventional three-phase input / three-phase output PWM cycloconverter.
FIG. 7 is a circuit diagram of a bidirectional switch.
FIG. 8 is a block diagram showing a connection form of an IGBT, a drive circuit, and an insulated power supply.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 3 phase power supply 2 Input filter 3 Bidirectional switch group 4 Induction motor 5 Power converters 11-19 Bidirectional switch 31, 32, 40, 311, 321, 411, 421, 511, 521 IGBT
33, 34, 331, 341, 431, 441, 531, 541 Diode 300 Bidirectional switch group 301, 401, 501, 351, 451, 551 Bidirectional switch 600 Output terminal 610, 611, 612 Input terminal 700 Insulated power supply group 701 , 702, 703, 704 Insulated power supply 800 Drive circuit group 801, 802, 803, 811, 812, 813 Drive circuit C1 Collector terminal G1 Gate terminal E1 Emitter terminals PN1, PN2, PN3, PN4 Power supply terminals GND1, GND2, GND3, GND4 Ground terminal PS1 Insulated power supply D1 Drive circuit PSG1 Insulated power supply PS1 ground terminal DG1 Drive circuit D1 ground terminal

Claims (6)

Three input terminals for inputting AC power of a three-phase AC power source for each phase;
One output terminal for outputting one-phase alternating current of an arbitrary frequency ;
A bidirectional switch group bidirectional switch formed by combining two uni-directional switch in the opposite direction is the are inserted one by one between each of said output terminals and the input terminals,
A drive circuit group including a drive circuit for driving the one-way switch for each of the one-way switches ;
An insulated power supply group comprising a plurality of insulated power supplies for supplying power to each of the drive circuits;
A three-phase input / one- phase output power conversion device, characterized by being configured as a single device. Each bidirectional switch is configured based on two IGBTs connected in opposite directions to each other,
The driving circuit for driving the one-way switch is for driving the IGBT,
An insulated power supply configured to connect the emitters of three IGBTs constituting each one-way switch connected from each input terminal to the output terminal in common with the output terminal, and supply power to each drive circuit of the IGBT. Shared
The three-phase input / 1-phase output power converter according to claim 1. Each bidirectional switch is configured based on two IGBTs connected in opposite directions to each other,
The driving circuit for driving the one-way switch is for driving the IGBT,
An insulated power supply for supplying power to each drive circuit of the IGBT is shared by connecting the emitters of the two IGBTs constituting each bidirectional switch among the IGBTs in common.
The three-phase input / 1-phase output power converter according to claim 1. In the three-phase input / three-phase output PWM cycloconverter,
Using serial mounting power converter of the three-phase input / single-phase output in claim 1 constitute a first output phase, 3-phase input / 3 phase comprising the said configuration for each output phase Output PWM cycloconverter. In the three-phase output multiplex type PWM cycloconverter,
The power converter of three-phase input / single-phase output of the placing serial to claim 1 more, constitute one of the output phases are connected in series, characterized by comprising the structure for each output phase 3 Phase output multiplex type PWM cycloconverter. In the three-phase output multiplex type PWM cycloconverter,
A plurality of power conversion devices of the three-phase input / single-phase output according to claim 1, connected in parallel to constitute the first output phase, 3-phase, characterized in that with the configuration for each output phase Output multiplex type PWM cycloconverter.

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