JP2011234439A - Power conversion equipment and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion equipment which can supply a load with an AC current having desired frequency from an AC voltage source, has small change in the peak value of the voltage supplied to the load, and in which loss is low, and to provide a control method of the power conversion equipment.SOLUTION: A power conversion equipment 10 comprises: reactor Lacs 1 to 3 connected to each phase of a three-phase AC power supply 21; a three-phase bridge MERS 100; a DC AC conversion circuit 200; and a control circuit 300. The control circuit 300 controls on/off of six reverse conduction type semiconductor switches constituting the three-phase bridge MERS 100 in order to repeatedly generate a DC voltage of pulse format in a capacitor CM of the three-phase bridge MERS 100. The DC voltage of pulse format generated in the capacitor CM is converted into AC voltage via the DC AC conversion circuit 200 so as to be applied to inductive loads LD1, LD2, and LD3.

Description

  The present invention relates to a power conversion device and a control method.

  Patent Document 1 discloses a low-loss AC / DC power converter that can supply DC power from an AC voltage source to a load.

This AC / DC power converter includes an AC reactor connected in series with an AC power source, a series circuit of the AC power source and the AC reactor connected between AC terminals, and a MERS in which a DC load is connected between DC terminals. And comprising.
This AC / DC power converter generates a pulsed DC voltage in MERS by turning on and off a reverse conductive semiconductor switch of MERS. The MERS capacitor that generates the pulsed DC voltage functions as a DC voltage source. The switching of MERS is soft switching.

When an inductive load is connected between the DC terminals of the AC / DC power conversion device via an inverter that converts DC power to AC power, AC power can be supplied to the inductive load.
In addition, since the MERS capacitor has a period during which the voltage is zero, by switching the inverter during the period when the MERS capacitor voltage is zero, soft switching is also realized in the inverter.

JP 2008-193817 A

However, when a three-phase inverter connected to an inductive load such as a three-phase motor is connected as the load of the AC / DC power converter described in Patent Document 1, the pulsed DC voltage generated in the MERS capacitor There was a problem that the fluctuation of the peak value became large.
When the fluctuation of the peak is large, the maximum value of the voltage applied to the inductive load becomes large even when the same power is supplied compared to the case where the fluctuation is small. Therefore, it is necessary to increase the withstand voltage of the inductive load. If the withstand voltage is large, the inductive load becomes large, and the entire system is poor in transportability and economical.

  The present invention has been made in view of the above-described problems, and an alternating current having a desired frequency can be supplied from an alternating voltage source to a load, the fluctuation of the peak value of the voltage supplied to the load is small, and the loss is low. An object is to provide a power conversion device and a control method.

In order to achieve the above object, a power conversion device according to a first aspect of the present invention includes:
A reactor that stores electric power supplied from an AC power source as magnetic energy;
A magnetic energy regenerative switch that includes a capacitor, recovers the magnetic energy of the reactor, and stores the energy in the capacitor as electrostatic energy;
A first DC input terminal connected to one pole of the capacitor; a second DC input terminal connected to the other pole of the capacitor; and a first DC input terminal connected to each phase of a three-phase inductive load. 1 to 3rd AC output terminals, 1st to 6th diodes, and 1st to 6th self-extinguishing elements, and the first DC input terminal includes the first diode. The cathode of the third diode, the cathode of the fifth diode, and the cathode of the fifth diode are connected to the second DC input terminal at the anode of the second diode, the anode of the fourth diode, and the sixth diode. The anode of the diode is connected, the anode of the first diode and the cathode of the second diode are connected to the first AC output terminal, and the third diode is connected to the second AC output terminal. Anode and said And the third AC output terminal is connected to the anode of the fifth diode and the cathode of the sixth diode, and the first diode is connected to the first self-extinguishing element. The second self-extinguishing element is provided in the second diode, the third self-extinguishing element is provided in the third diode, and the fourth self-extinguishing type is provided in the fourth diode. The fifth diode is connected to the fifth self-extinguishing element, the sixth diode is connected to the sixth self-extinguishing element in parallel, and the first to sixth self-extinguishing elements are connected in parallel. A DC / AC conversion circuit that outputs a DC voltage generated in the capacitor to the inductive load from the first to third AC output terminals in response to ON / OFF of the arc-extinguishing element;
Control means for controlling on / off of the first to sixth self-extinguishing elements;
With
The control means controls on / off of the first to sixth self-extinguishing elements so that a plurality of on / off of the first to sixth self-extinguishing elements are not switched at substantially the same timing. To
It is characterized by that.

  For example, the control means may prevent the third to sixth self-extinguishing elements from being switched on / off at substantially the same timing when the first self-extinguishing elements are switched on / off. The third self-extinguishing element is turned on and off so that the third to sixth self-extinguishing elements are not turned on and off at substantially the same timing when the self-extinguishing element is turned on and off. The fourth self-extinguishing element is turned on so that the first, second, fifth, and sixth self-extinguishing elements are not turned on and off at substantially the same timing when the off is switched. On / off of the fifth self-extinguishing element so that the on / off of the first, second, fifth, and sixth self-extinguishing elements is not switched at substantially the same timing at which the off is switched. At the same timing when the The first to fourth self-extinguishing elements at approximately the same timing at which the sixth self-extinguishing element is switched on and off so that the fourth self-extinguishing element is not switched on and off. The first to sixth self-extinguishing elements are controlled so as not to be switched on / off.

  For example, the DC voltage generated in the capacitor is a pulsed DC voltage.

  For example, the control means switches on / off of the first to sixth self-extinguishing elements when the voltage of the capacitor is substantially zero.

  For example, the control means does not turn on both the first and fourth self-extinguishing elements and does not turn on both the second and fifth self-extinguishing elements. The first to sixth self-extinguishing elements are controlled so that both of the six self-extinguishing elements are not turned on.

  For example, the control means controls on / off of the first to sixth self-extinguishing elements by a pulse pattern.

  For example, the control means controls on / off of the first to sixth self-extinguishing elements by pulse width modulation.

For example, the AC power source is a three-phase AC power source,
The reactor includes a first reactor having one end connected to the first phase of the three-phase AC power source, a second reactor having one end connected to the second phase, and a third reactor having one end connected to the third phase. Consisting of
The magnetic energy regeneration switch includes first to third AC input terminals, first and second DC output terminals, seventh to twelfth diodes, seventh to twelfth self-extinguishing elements, , A capacitor, and the first AC input terminal includes the other end of the first reactor, the anode of the seventh diode, and the cathode of the eighth diode at the second AC input terminal. The other end of the second reactor, the anode of the ninth diode, and the cathode of the tenth diode are connected to the third AC input terminal and the other end of the third reactor and the eleventh electrode. The anode of the diode and the cathode of the twelfth diode are connected, and the first DC output terminal has a cathode of the seventh diode, a cathode of the ninth diode, and the eleventh die. The cathode of the first electrode and one pole of the capacitor are connected to the second DC output terminal of the anode of the eighth diode, the anode of the tenth diode, the anode of the twelfth diode, and the capacitor. The other electrode is connected, the seventh self-extinguishing element is connected to the seventh diode, the eighth self-extinguishing element is connected to the eighth diode, and the ninth diode is connected to the ninth diode. A ninth self-extinguishing element is provided in the tenth diode, the tenth self-extinguishing element is provided in the eleventh diode, and the eleventh self-extinguishing element is provided in the twelfth diode. The twelfth self-extinguishing element is a three-phase bridge magnetic energy regenerative switch connected in parallel;
The control means controls on / off of the first to twelfth self-extinguishing elements.

  For example, the voltage of the capacitor immediately before the seventh to twelfth self-extinguishing elements change from off to on is approximately zero.

  For example, the current flowing through the seventh to twelfth self-extinguishing elements immediately before the seventh to twelfth self-extinguishing elements change from off to on is substantially zero.

  For example, when the output of the first phase of the three-phase AC power supply is positive, the control means repeatedly switches the seventh self-extinguishing element and keeps the eighth self-extinguishing element off. When the output of the first phase is negative, the eighth self-extinguishing element is repeatedly switched on and off, and the seventh self-extinguishing element is held off. When the output is positive, the ninth self-extinguishing element is repeatedly switched and the tenth self-extinguishing element is held off, and when the second phase output is negative, the tenth self-extinguishing element is turned off. The self-extinguishing element is repeatedly switched on and off and the ninth self-extinguishing element is held off. When the third phase output is positive, the eleventh self-extinguishing element is repeated. Switching and holding the twelfth self-extinguishing element off to output the third phase If negative repeatedly switched on and off of the first 12 of the self-extinguishing type switching elements, and is held in the first 11 off the self extinguishing type switching elements of the.

For example, the magnetic energy regeneration switch includes a first AC input terminal, a second AC input terminal in which a series circuit of the AC power source and a reactor is connected between the first AC input terminal, a first AC input terminal, And a second DC output terminal, a capacitor connected between the first and second DC output terminals, seventh to tenth diodes, seventh to tenth self-extinguishing elements, The first AC input terminal includes the anode of the seventh diode and the cathode of the eighth diode, and the second AC input terminal includes the anode of the ninth diode and the tenth diode. The cathode of the seventh diode and the cathode of the ninth diode are connected to the first DC output terminal, and the cathode of the ninth diode is connected to the eighth DC terminal. Diode diode And the anode of the tenth diode are connected, the seventh self-extinguishing element is connected to the seventh diode, and the eighth self-extinguishing element is connected to the eighth diode, A full-bridge magnetic energy regenerative switch in which the ninth self-extinguishing element is connected to the ninth diode, and the tenth self-extinguishing element is connected to the tenth diode;
The control means controls on / off of the first to tenth self-extinguishing elements.

  For example, the voltage of the capacitor immediately before the seventh to tenth reverse conducting semiconductors change from off to on is approximately zero.

  For example, the current flowing through the seventh to tenth reverse conducting semiconductor switches immediately before the seventh to tenth reverse conducting semiconductors change from off to on is substantially zero.

  The control means repeatedly switches the eighth and ninth self-extinguishing elements and keeps the seventh and tenth self-extinguishing elements off when the output voltage of the AC power supply is positive. When the output voltage is negative, the seventh and tenth self-extinguishing elements may be repeatedly switched on and off, and the eighth and ninth self-extinguishing elements may be held off. .

In order to achieve the above object, a control method according to a second aspect of the present invention includes:
A reactor that stores electric power supplied from an AC power source as magnetic energy;
A magnetic energy regenerative switch that includes a capacitor, recovers the magnetic energy of the reactor, and stores the energy in the capacitor as electrostatic energy;
A first DC input terminal connected to one pole of the capacitor; a second DC input terminal connected to the other pole of the capacitor; and a first DC input terminal connected to each phase of a three-phase inductive load. 1 to 3rd AC output terminals, 1st to 6th diodes, and 1st to 6th self-extinguishing elements, and the first DC input terminal includes the first diode. The cathode of the third diode, the cathode of the fifth diode, and the cathode of the fifth diode are connected to the second DC input terminal at the anode of the second diode, the anode of the fourth diode, and the sixth diode. The anode of the diode is connected, the anode of the first diode and the cathode of the second diode are connected to the first AC output terminal, and the third diode is connected to the second AC output terminal. Anode and said And the third AC output terminal is connected to the anode of the fifth diode and the cathode of the sixth diode, and the first diode is connected to the first self-extinguishing element. The second self-extinguishing element is provided in the second diode, the third self-extinguishing element is provided in the third diode, and the fourth self-extinguishing type is provided in the fourth diode. The fifth diode is connected to the fifth self-extinguishing element, the sixth diode is connected to the sixth self-extinguishing element in parallel, and the first to sixth self-extinguishing elements are connected in parallel. A DC / AC conversion circuit that converts a DC voltage generated in the capacitor into an AC voltage and applies it to the inductive load corresponding to on / off of the arc-extinguishing type element; and
A control method for controlling on / off of the first to sixth self-extinguishing elements in a power conversion device comprising:
Controlling on / off of the first to sixth self-extinguishing elements so that a plurality of on / off of the first to sixth self-extinguishing elements are not switched at substantially the same timing;
It is characterized by that.

  ADVANTAGE OF THE INVENTION According to this invention, the alternating current power of a desired frequency can be supplied to a load by applying to a load the pulse-form voltage with little fluctuation | variation of a voltage peak value from an alternating current power supply with low loss.

It is a circuit diagram which shows the structure of the power converter device which concerns on embodiment of this invention. It is a figure for demonstrating the control which the power converter device of FIG. 1 performs. (A) thru | or (f) is a figure for demonstrating the control which the power converter device of FIG. 1 performs. It is a figure for demonstrating the operation | movement which generates the pulsed DC voltage from AC power supply of the power converter device shown in FIG. It is a figure for demonstrating the operation | movement which generates the pulsed DC voltage from AC power supply of the power converter device shown in FIG. It is a figure for demonstrating the operation | movement which generates the pulsed DC voltage from AC power supply of the power converter device shown in FIG. It is a figure for demonstrating the operation | movement which generates the pulsed DC voltage from AC power supply of the power converter device shown in FIG. (A) thru | or (c) is a figure for demonstrating the relationship between the gate signal which the power converter device of FIG. 1 outputs, the pulse-form DC voltage which generate | occur | produces in a capacitor | condenser, and the electric current which flows into a reactor. It is a figure for demonstrating the operation | movement which supplies alternating current power to a load from the pulse-form DC voltage of the power converter device shown in FIG. It is a figure for demonstrating the operation | movement which supplies alternating current power to a load from the pulse-form DC voltage of the power converter device shown in FIG. It is a figure for demonstrating the operation | movement which supplies alternating current power to a load from the pulse-form DC voltage of the power converter device shown in FIG. It is a figure for demonstrating the operation | movement which supplies alternating current power to a load from the pulse-form DC voltage of the power converter device shown in FIG. (A) thru | or (j) is a figure which shows the relationship between the gate signal by the conventional control method, the electric current which flows into an inductive load, and the voltage which generate | occur | produces in a capacitor | condenser in the power converter device shown in FIG. . (A) thru | or (j) is a figure which shows the relationship between the gate signal by the control method concerning this invention, the electric current which flows into an inductive load, and the voltage which generate | occur | produces in a capacitor | condenser in the power converter device shown in FIG. It is. (A), (b) is a pulsed direct current generated in the capacitor in the case of supplying AC power to the load from the pulsed direct current voltage generated in the capacitor by soft switching in the power converter shown in FIG. It is a figure which shows the relationship between a voltage and the gate signal controlled by a pulse pattern. (A) thru | or (c) are the pulse-form DC voltage which generate | occur | produces in a capacitor | condenser in the case of supplying alternating current power to the load from the pulse-form DC voltage which generate | occur | produces in a capacitor | condenser in the power converter device shown in FIG. It is a figure which shows the relationship with the gate signal controlled by (Pulse Width Modulation). It is a figure which shows the application example of the power converter device of FIG. It is a figure which shows the application example of the power converter device of FIG.

  Hereinafter, a power converter according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1)
As shown in FIG. 1, the power conversion device 10 according to the present embodiment includes reactors Lac1, Lac2, and Lac3, a three-phase bridge type MERS100, a DC / AC conversion circuit 200, and a control circuit 300. It is connected between the phase AC power supply 21 and the three inductive loads LD1, LD2, and LD3.

The three-phase bridge type MERS 100 includes six reverse conducting semiconductor switches SWU, SWV, SWW, SWX, SWY, SWZ, a capacitor CM, AC input terminals AC1, AC2, AC3, and DC output terminals DCP, DCN. It is configured.
The DC / AC converter circuit 200 includes six reverse conducting semiconductor switches SWu, SWv, SWw, SWx, SWy, SWz, DC input terminals DC +, DC−, and AC output terminals ACu, ACv, ACw. Yes.
The reverse conducting semiconductor switches SWU to SWZ, SWu to SWz include diode units DU to DZ, Du to Dz, and switch units SU to SZ, Su to Sz connected in parallel to the diode units DU to DZ, Du to Dz. And gates GU to GZ and Gu to Gz disposed in the switch units SU to SZ and Su to Sz.

The switch units SU to SZ and Su to Sz are turned on when an on signal is input to the gates GU to GZ and Gu to Gz, and are turned off when an off signal is input.
When the switch units SU to SZ and Su to Sz are turned on, the diode units DU to DZ and Du to Dz are short-circuited, and the forward and reverse directions of the reverse conducting semiconductor switches SWU to SWZ and SWu to SWz are turned on.
When the switch units SU to SZ, Su to Sz are turned off, the diode units DU to DZ, Du to Dz function, and the reverse conducting semiconductor switches SWU to SWZ, SWu to SWz are only the diode units DU to DZ, Du to Dz. One-way on.
The reverse conducting semiconductor switches SWU to SWZ and SWu to SWz are, for example, N-channel silicon MOSFETs (MOSFETs: Metbl-Oxide-Semiconductor Field-Effect Transistors) having parasitic diodes.

The three-phase AC power source 21 is composed of AC voltage sources VS1, VS2, and VS3. Outputs of the AC voltage sources VS1, VS2, and VS3 are connected to one ends of the reactors Lac1, Lac2, and Lac3.
The three-phase AC power source 21 is, for example, a three-phase AC generator with a rated output of 50 Hz and 2125V.

The other ends of reactors Lac1, Lac2, and Lac3 are connected to AC input terminals AC1, AC2, and AC3 of three-phase bridge type MERS100.
Reactors Lac1 to Lac3 accumulate electric power supplied from three-phase AC power supply 21 as magnetic energy when current flows.

  The AC input terminal AC1 of the three-phase bridge type MERS100 has an anode of the diode unit DU and a cathode of the diode unit DX, and the AC input terminal AC2 has an anode of the diode unit DV and a cathode of the diode unit DY. Are connected to the anode of the diode part DW and the cathode of the diode part DZ. The DC output terminal DCP is connected to the cathodes of the diode parts DU, DV, DW, the positive electrode of the capacitor CM, and the DC input terminal DC + of the DC / AC converter circuit 200. However, the anodes of the diode portions DX, DY, DZ, the negative electrode of the capacitor CM, and the DC input terminal DC− of the DC / AC conversion circuit 200 are connected to the DC output terminal DCN.

  The three-phase bridge type MERS100 collects magnetic energy stored in the reactors Lac1 to Lac3 as electrostatic energy in the form of electric charges in the capacitors Lac1 to Lac3 as the reverse conducting semiconductor switches SWU to SWZ are turned on and off. The recovered energy is returned to the reactors Lac1 to Lac3 again. The voltage Vcm between the terminals of the capacitor CM is applied between the DC output terminals DCP-DCN.

The DC input terminal DC + of the DC / AC converter circuit 200 is connected to the cathodes of the diode portions Du, Dv, Dw, the DC input terminal DC− is connected to the anodes of the diode portions Dx, Dy, Dz, and the AC output terminal ACu is connected to the diode. The anode of the part Du, the cathode of the diode part Dx, and one end of the inductive load LD1 are connected to the AC output terminal ACv. The anode of the diode part Dv, the cathode of the diode part Dy, and one end of the inductive load LD2 are connected to the AC output terminal. The anode of the diode part Dw, the cathode of the diode part Dz, and one end of the inductive load LD3 are connected to ACw.
The DC / AC converter circuit 200 outputs a DC voltage applied between the DC input terminals DC + and DC− to the AC output terminals ACu to ACw in accordance with the turning on / off of the reverse conducting semiconductor switches USW to ZSW. AC voltage is applied to the capacitive loads LD1, LD2, and LD3.

  The inductive loads LD1, LD2, and LD3 are represented by a series circuit of an inductance L1 and a resistor R1, a series circuit of an inductance L2 and a resistor R2, and a series circuit of an inductance L3 and a resistor R3, respectively. Inductive loads LD1, LD2, and LD3 are, for example, each phase of a three-phase motor.

The control circuit 300 includes reverse conducting semiconductor switches SWU, SWV, SWW, SWX, SWY, SWZ, SWu, SWv, SWw, SWx, SWy, and SWz gates GU, GV, GW, GX, GY, GZ, Gu, Gv. , Gw, Gx, Gy, Gz, gate signals SGGU, SGGV, SGGW, SGGX, SGGY, SGGZ, SGGu, SGGv, SGGw, SGGx, SGGy, SGGz are output.
The control circuit 300 is an electronic circuit that includes, for example, a comparator, a flip-flop, and a timer.

The gate signals SGGU to SGGZ, SGGu to SGGz are composed of an on signal and an off signal, and switch on / off of the reverse conducting semiconductor switches SWU to SWZ, SWu to SWz.
The on signal / off signal of the gate signals SGGU to SGGZ, SGGu to SGGz is, for example, a voltage whose on signal is a high level and a voltage whose off signal is a low level.

  When the voltage output from the AC voltage source VS1 is positive by the gate signals SGGU to SGGZ, the control circuit 300 controls on / off of the reverse conducting semiconductor switch SWX and keeps the reverse conducting semiconductor switch SWU off. When the voltage output from the AC voltage source VS1 is negative, the reverse conducting semiconductor switch SWU is controlled to be turned on / off, and the reverse conducting semiconductor switch SWX is kept off. Similarly, when the voltage output from the AC voltage source VS2 is positive, the reverse conducting semiconductor switch SWY is controlled to be turned on and off to keep the reverse conducting semiconductor switch SWV off. When the voltage is negative, the reverse conducting semiconductor switch When the reverse conduction type semiconductor switch SWY is kept off by controlling ON / OFF of the SWV, and the voltage output from the AC voltage source VS3 is positive, the reverse conduction type semiconductor switch SWZ is controlled by turning on / off the reverse conduction type semiconductor switch SWZ. The switch SWW is kept off, and if negative, the reverse conducting semiconductor switch SWW is controlled to be turned on / off to keep the reverse conducting semiconductor switch SWZ off.

When the ON / OFF of the reverse conducting semiconductor switches SWU to SWZ is controlled, the ON / OFF signal time of the gate signals SGGU to SGGZ is the capacitor immediately before the gate signals SGGU to SGGZ change from the ON signal to the OFF signal. Pre-adjustment so that the CM voltage Vcm is substantially zero, and the current flowing through the reverse conducting semiconductor switches SWU to SWZ immediately before the gate signals SGGU to SGGZ change from the off signal to the on signal is substantially zero. Has been. The period of the on signal / off signal is preferably longer than the half cycle of resonance determined by the capacitance of the capacitor CM and the inductances of the reactors Lac1 to Lac3.
For example, as illustrated in FIG. 2, the control circuit 300 uses the gate signals SGGU to SGGZ having a duty ratio of 0.4 for the on signal and the off signal and a frequency f of 5 kHz, and the alternating voltage sources VS1 to VS1 to ON / OFF of reverse conducting semiconductor switches SWU to SWZ corresponding to positive / negative of the output voltage of VS3 is controlled.

  The control circuit 300 outputs gate signals SGGu to SGGz having a preset pulse pattern to the gates Gu to Gz of the reverse conducting semiconductor switches SWu to SWz. This pulse pattern is, for example, a multi-pulse pulse width modulation pulse pattern used in a current type inverter as shown in FIG.

  As shown in FIG. 3, the gate signal SGGu and the gate signal SGGx are opposite to each other in the on signal / off signal. Similarly, the gate signal SGGv and the gate signal SGGy are opposite in the on signal / off signal from each other. The SGGw and the gate signal SGGz are opposite in ON signal / OFF signal.

Similarly, the control circuit 300 is configured so that the reverse conduction type semiconductor switches SWv and SWy are turned on / off so that the reverse conduction type semiconductor switches SWu and SWx are not turned on / off. And the gate signals SGGu to SGGz are controlled so that both ON and OFF of SWz do not turn ON.
This is to prevent the capacitor CM from being short-circuited via the reverse conducting semiconductor switches SWu to SWz.

Further, in the power conversion device 10 according to the present invention, the gate signals SGGu and SGGx are different from the conventional pulse pattern, and the timing of switching the on signal / off signal of the pair of the gate signals SGGu and SGGx, and the gate signals SGGv and SGGy. The timing at which the ON signal / OFF signal of the pair of the signals is switched and the timing at which the ON signal / OFF signal of the pair of the gate signals SGGw and SGGz are switched are controlled to be different from each other.
Therefore, the reverse conduction semiconductor switches SWv, SWy, SWw, and SWz are not turned on and off at substantially the same timing when the reverse conduction semiconductor switch SWu is turned on / off, and the reverse conduction semiconductor switch SWx is turned on.・ On / off of reverse conducting semiconductor switches SWv, SWy, SWw, and SWz does not switch at substantially the same timing when switching off, and reverse conducting at approximately the same timing when reverse conducting semiconductor switch SWv switches on / off. ON / OFF of the type semiconductor switches SWu, SWx, SWw, and SWz is not switched, and the reverse conduction type semiconductor switches SWu, SWx, SWw, and SW are switched at substantially the same timing when the reverse conduction type semiconductor switch SWy is switched on / off. , SWz is not switched on / off, The reverse conduction semiconductor switches SWu, SWx, SWv, and SWy are not turned on and off at substantially the same timing when the conduction type semiconductor switch SWw is turned on and off, and the reverse conduction type semiconductor switch SWz is turned on and off. The reverse conducting semiconductor switches SWu, SWx, SWv, and SWz are not switched on and off at substantially the same timing when switching.
This point is new to the conventional control method. The effect will be described later.

Next, the operation of the power conversion device 10 configured as described above will be described.
First, an operation for generating a voltage in the capacitor CM will be described with reference to FIGS. 4A to 4D.

In order to facilitate understanding, an operation when the voltage output from the AC voltage source VS1 is higher than the voltage output from the AC voltage source VS2 will be described. 4A to 4D, the AC voltage source VS3, the reverse conducting semiconductor switches SWW and SWZ, the DC / AC conversion circuit 300, and the inductive loads LD1, LD2, and LD3 are omitted.
Assume that the initial state is the state of FIG. 4D in which charges are accumulated in the capacitor CM and the reverse conducting semiconductor switches SWU, SWV, SWX, SWY are off.

At time t1 determined by a preset frequency f, the control circuit 300 switches the gate signals SGGV and SGGX to the on signal and holds the reverse conducting semiconductor switches SWU and SWY as the off signal.
The reverse conducting semiconductor switches SWV and SWX are switched on, and the reverse conducting semiconductor switches SWU and SWY are kept off.
Then, as shown in FIG. 4A, a current flows from the AC voltage source VS1 through the AC input terminal AC1 to the negative electrode of the capacitor CM via the ON reverse conducting semiconductor switch SWX. The current flowing out from the positive electrode of the capacitor CM passes through the AC input terminal AC2 via the ON reverse conducting semiconductor switch SWV and flows through the AC voltage source VS2. The voltage Vcm of the capacitor CM is applied between the DC output terminals DCP and DCN, and the electrostatic energy accumulated in the capacitor CM is supplied to the inductive loads LD1 to LD3 via the DC / AC conversion circuit 200.

At time t2 when all the electric charge of the capacitor CM is discharged, as shown in FIG. 4B, a current flows from the AC input terminal AC1 through the off reverse conducting semiconductor switch SWU and the on reverse conducting semiconductor switch SWV. , And flows through the two routes of the route passing through the reverse reverse conducting semiconductor switch SWX and the off reverse conducting semiconductor switch SWY to the AC input terminal AC2.
The reactance Lac1 and the reactance Lac2 store magnetic energy as a current flows. The voltage Vcm of the capacitor CM hardly changes.

The control circuit 300 switches the gate signals SGGV and SGGX to the off signal at time t3 with a preset duty ratio. The gate signals SGGU and SGGY are held as off signals.
The reverse conducting semiconductor switches SWV and SWX are switched off, and the reverse conducting semiconductor switches SWU and SWY are kept off.
The current flowing through the reverse conduction type semiconductor switch SWV and the current flowing through the reverse conduction type semiconductor switch SWX are cut off, and the magnetic energy accumulated in the reactors Lac1 and Lac2 causes the current to flow as shown in FIG. Flows into the positive electrode of the capacitor CM through the diode portion DU. As a result, the capacitor CM accumulates the magnetic energy accumulated in the reactors Lac1 and Lac2 as electrostatic energy in the form of electric charges. The current flowing from the negative electrode of the capacitor CM flows through the AC input terminal AC2 via the OFF reverse conducting semiconductor switch SWY diode portion DY. The voltage Vcm of the capacitor CM is applied between the DC output terminals DCP-DCN, and the electrostatic energy accumulated in the capacitor CM is inductive load LD1 via the DC-AC conversion circuit 200 using the capacitor CM as a DC voltage source. To LD3.
Since the voltage of the capacitor CM is substantially 0 from time t2 to time t3, switching at time t3 is soft switching.

  When the magnetic energy accumulated in reactors Lac1 and Lac2 disappears at time t4, the current flowing from AC input terminal AC1 to AC input terminal AC2 is cut off as shown in FIG. 4D. The voltage Vcm of the capacitor CM is applied between the DC output terminals DCP and DCN, and the electrostatic energy accumulated in the capacitor CM is supplied to the inductive loads LD1 to LD3 via the DC / AC conversion circuit 200.

At time t5 determined by the preset frequency f, the control circuit 300 switches the gate signals SGGV and SGGX to the on signal again and holds the reverse conducting semiconductor switches SWU and SWY as the off signal. The reverse conducting semiconductor switches SWV and SWX are switched on, and the reverse conducting semiconductor switches SWU and SWY are kept off.
Then, a current flows again as shown in FIG. 4A, and the electrostatic energy accumulated in the capacitor CM is released.
From time t4 to time t5, as can be seen from FIG. 4D, no current flows through the reverse conducting semiconductor switches SWU and SWY. Therefore, switching at time t5 is soft switching.

  As described above, in the power conversion device 10, the modes shown in FIGS. 4A to 4D are repeated in each phase of the three-phase AC power supply 21, and the pulsed DC that vibrates between about 0 and the peak in the capacitor CM. Voltage is generated repeatedly.

  As described above, a pulsed DC voltage oscillating between the peak and about 0 is repeatedly generated in the capacitor CM in response to the on / off of the reverse conducting semiconductor switches SWU to SWZ, and this voltage is generated by the DC output terminal DCP. -Applied between DCN.

The relationship between the gate signals SGGX and SGGV, the voltage Vcm applied between the terminals of the capacitor CM, and the current ILac1 flowing through the reactor Lac1 is as shown in FIGS. 5A to 5C, for example.
FIG. 5 shows an example of the time change of the voltage Vcm generated in the capacitor CM. FIG. 5A shows the time change of the voltage Vcm, FIG. 5B shows the time change of the current ILac1, and FIG. c) shows the time change of the gate signals SGGX and SGGV. T1 to t5 in the figure correspond to times t1 to t5 in FIGS. 4A to 4D.

As the control circuit 300 controls the ON / OFF of the reverse conducting semiconductor switches SWU to SWZ as described above, the capacitor CM and the reactors Lac1, Lac2, and Lac3 resonate, as shown in FIG. A pulsed DC voltage that oscillates between about 0 and the peak is generated in the capacitor CM.
Therefore, as shown in FIGS. 5A and 5C, the capacitor CM is charged and discharged once during one cycle of the ON signal / OFF signal of the gate signals SGGU to SGGZ output by the control circuit 300. Complete.

Further, as described above, the voltage of the capacitor CM is substantially zero at the time when the gate signals SGGU to SGGZ change from the on signal to the off signal (for example, time t3). Therefore, as shown in FIGS. 5A and 5C, switching at time t3 is soft switching.
Further, as described above, at the time when the gate signals SGGU to SGGZ change from the off signal to the on signal (for example, time t5), no current flows through the reverse conducting semiconductor switches SWU and SWY. Therefore, as shown in FIGS. 5B and 5C, when the ON signal / OFF signal of the gate signals SGGU to SGGZ is switched, soft switching is performed.
That is, when the gate signals SGGX to SGGV are switched between ON and OFF signals, the voltage applied to the reverse conducting semiconductor switches SWU to SWZ is substantially 0 or the current is substantially 0. It is.

  In the period from time t3 to time t4, as shown in FIG. 4C, the capacitor CM forms a series resonance circuit with the reactors Lac1 and Lac2. Therefore, the time from time t1 when charge does not accumulate in the capacitor CM and current flows through the reactors Lac and Lac2 to time t4 when charge accumulates in the capacitor CM and current does not flow through the reactors Lac and Lac2 And the resonance period of the series circuit of reactors Lac1 and Lac2 is approximately one-fourth.

As described above, by turning on / off the reverse conducting semiconductor switches SWU to SWZ in response to the on / off signals of the gate signals SGGX to SGGV, a pulsed DC voltage is applied to the capacitor CM of the full bridge type MERS100. Occurs.
Further, the on / off switching of the reverse conducting semiconductor switches SWU to SWZ is soft switching.

  Next, the currents ILD1, ILD2, and ILD3 flowing through the inductive loads LD1, LD2, and LD3 will be described with reference to FIGS. 6A to 6D. The arrows shown in FIGS. 6A, 6B, and 6C indicate the positive direction in which the current flows.

When only one of the reverse conduction type semiconductor switches SWu, SWv, SWw is on, for example, when the reverse conduction type semiconductor switches SWu, SWy, SWz are on, and the reverse conduction type semiconductor switches SWx, SWv, SWw are off The current flows as shown in FIG. 6A.
The voltage Vcm of the capacitor CM is applied between the AC output terminals ACu-ACv and ACu-ACw. The current Iin flowing from the DC input terminal DC + flows through the inductive load LD1 through the reverse conducting semiconductor switch SWu which is on regardless of the positive / negative. The currents ILD2 and ILD3 flowing through the inductive loads LD2 and LD3 from the common contact point of the inductive loads LD1, LD2 and LD3 pass through the reverse-conducting semiconductor switches SWy and SWz which are turned on regardless of the positive / negative, and the DC input terminal It flows through DC-.
The relationship between the current Iin flowing from the DC input terminal DC +, the currents ILD1, ILD2, and ILD3 flowing through the inductive loads LD1, LD2, and LD3, and the current Iout flowing to the DC input terminal DC− is based on Kirchhoff's first law: Iin = ILD1 = ILD2 + ILD3 = Iout holds.

When two of the reverse conducting semiconductor switches SWu, SWv, SWw are on, for example, when the reverse conducting semiconductor switches SWu, SWv, SWz are on and the reverse conducting semiconductor switches SWx, SWy, SWw are off, The current flows as shown in FIG. 6B.
The voltage Vcm of the capacitor CM is applied between the AC output terminals ACu-ACw and between ACv-ACw. A current Iin flowing from the DC input terminal DC + is divided into a current ILD1 and a current ILD2, and flows through the inductive loads LD1 and LD2 through the ON reverse conducting semiconductor switches SWu and SWv regardless of the positive or negative. The current ILD3 flowing through the inductive load LD3 from the common contact of the inductive loads LD1, LD2, and LD3 passes through the ON reverse conducting semiconductor switch SWz and flows through the DC input terminal DC− regardless of the positive / negative.

When all of the reverse conducting semiconductor switches SWu, SWv, SWw are off, current flows as shown in FIG. 6C.
No power is supplied from the three-phase bridge type MERS 100 (current Iin is 0), and the voltage Vcm of the capacitor CM is not applied to the inductive loads LD1 to LD3. The currents ILD1 to ILD3 flowing through the inductive loads LD1 to LD3 pass through the ON reverse conducting semiconductor switches SWx, SWy, SWz regardless of whether the current is positive or negative depending on the magnetic energy accumulated by the flow of the current. Flowing.

When all of the reverse conducting semiconductor switches SWu, SWv, SWw are on, current flows as shown in FIG. 6D.
No power is supplied from the three-phase bridge type MERS 100 (current Iin is 0), and the voltage Vcm of the capacitor CM is not applied to the inductive loads LD1 to LD3. The currents ILD1 to ILD3 flowing through the inductive loads LD1 to LD3 pass through the ON reverse conducting semiconductor switches SWu, SWv, and SWw regardless of whether the current is positive or negative depending on the magnetic energy accumulated by the flow of the current. Flowing.

  As described above, the voltage Vcm is output between the AC output terminals ACu, ACv, and ACw in response to the ON / OFF of the reverse conducting semiconductor switches SWu, SWv, SWw, SWx, SWy, SWz, and the reverse conducting of ON. Current flows through the inductive loads LD1, LD2, and LD3 through the type semiconductor switches SWu to SWz, and AC power is supplied to the inductive loads LD1, LD2, and LD3.

  Next, the voltage Vcm applied to the capacitor CM and the inductive loads LD1, LD2, and LD3 according to the switching of the ON signal / OFF signal of the gate signals SGGu, SGGv, SGGw, SGGx, SGGy, and SGGz output from the control circuit 300. Changes in the currents ILD1, ILD2, and ILD3 flowing in the current will be described.

  First, in order to facilitate understanding, a case where the gate signals SGGu to SGGz are controlled with a conventional pulse pattern will be described with reference to FIG. That is, the ON signal / OFF signal switching timing of the gate signal SGGu and SGGx pair, the ON signal / OFF signal switching timing of the gate signal SGGv and SGGy pair, and the ON signal OFF of the gate signal SGGw and SGGz pair A case where the timing at which the signal is switched is not set to a different timing will be described.

FIG. 7 shows changes over time in the voltage Vcm applied to the capacitor CM, the gate signals SGGu to SGGz, and the load currents ILD1, ILD2, and ILD3 flowing through the inductive loads LD1, LD2, and LD3.
7A shows the voltage Vcm of the capacitor CM, FIGS. 7B to 7G show the gate signals SGGu to SGGz, and FIGS. 7H to 7J show the time changes of the load currents ILD1 to ILD3. Is.

By repeating the above operation, as shown in FIGS. 7H to 7J, sinusoidal currents ILD1 to ILD3 whose phases are shifted from each other by approximately 120 ° flow through the inductive loads LD1 to LD3.
However, for example, at time Tp1 when the gate signals SGGv and SGGw are simultaneously switched from the on signal to the off signal, the peak of the voltage Vcm rises rapidly (to about 15 kiloV in FIG. 7). Similarly, at time Tp2 when the gate signals SGGu and SGGw are simultaneously switched from the on signal to the off signal, at time Tp3 when the gate signals SGGu and SGGv are simultaneously switched from the on signal to the off signal, the peak of the voltage Vcm rapidly increases. . In this way, when the on / off of the two pairs of gate signals changes on and off almost simultaneously, the peak of the voltage Vcm rises rapidly.

  On the other hand, the gate signals SGGu, SGGv, SGGw, SGGx, SGGy, SGGz output from the control circuit 300 of the power converter 10 according to the present invention, the voltage Vcm, and the currents ILD1, ILD2 flowing through the inductive loads LD1, LD2, LD3. , ILD3 is, for example, as shown in FIG.

FIG. 8 shows changes over time in the voltage Vcm applied to the capacitor CM, the gate signals SGGu to SGGz, and the load currents ILD1, ILD2, and ILD3 flowing through the inductive loads LD1, LD2, and LD3.
8A shows the voltage Vcm of the capacitor CM, FIGS. 8B to 8G show the gate signals SGGu to SGGz, and FIGS. 8H to 8J show the time changes of the load currents ILD1 to ILD3. Is.

  In the power conversion device 10 according to the present embodiment, unlike the case of controlling with a conventional pulse pattern, as shown in FIG. 8, the timing of switching the on signal / off signal of the pair of the gate signals SGGv and SGGy, and the gate signal Two of the SGGw and SGGz on / off signal switching timings do not coincide with each other, and the peak of the voltage Vcm does not increase rapidly as in the prior art (12 km in FIG. 8). It only rises to V).

As described above, by switching on / off the reverse conducting semiconductor switches SWU to SWZ of the three-phase full bridge MERS100, a pulsed DC voltage is applied to the capacitor CM from the outputs of the AC voltage sources VS1, VS2, and VS3. The DC voltage is repeatedly generated, and this DC voltage is applied to the inductive loads LD1, LD2, and LD3 through the DC / AC conversion circuit 200, and a three-phase AC current can flow through the inductive loads LD1, LD2, and LD3.
In addition, since the plurality of on / off timings of the gate signals SGGu to SGGz are set to different timings, fluctuations in the peak of the resonance voltage generated in the capacitor CM can be suppressed.
In the above embodiment, the control circuit 300 is configured so that the reverse conducting semiconductor switches SWv, SWy, SWw, and SWz are not switched on / off at substantially the same timing when the reverse conducting semiconductor switch SWu is switched on / off. The reverse conducting semiconductor switch SWv is turned on / off so that the reverse conducting semiconductor switches SWv, SWy, SWw, and SWz are not turned on / off at substantially the same timing at which the reverse conducting semiconductor switch SWx is turned on / off. The reverse conducting semiconductor is switched at approximately the same timing when the reverse conducting semiconductor switch SWy is switched on and off so that the reverse conducting semiconductor switches SWu, SWx, SWw, and SWz are not switched on and off at substantially the same timing when the switching is performed. ON / OFF of switches SWu, SWx, SWw, and SWz So that the reverse conducting semiconductor switches SWu, SWx, SWv, and SWy are not switched on and off at substantially the same timing when the reverse conducting semiconductor switch SWw is switched on and off. Control of ON / OFF of the reverse conducting semiconductor switches SWu to SWz is performed so that the ON / OFF of the reverse conducting semiconductor switches SWu, SWx, SWv, and SWz is not switched at substantially the same timing when the switch SWz is switched on / off. is doing.

In the present embodiment, a pulse pattern is set in advance for each of the gate signals SGGu to SGGz. However, the gate signals SGGu to SGGz may be generated by setting one pulse pattern in advance, shifting the phase, inverting it, or the like.
For example, the gate signal SGGu applies the pulse pattern as it is, the gate signal SGGv shifts the pulse pattern by 120 °, the gate signal SGGw shifts the pulse pattern by 240 °, and the ON / OFF signals of the gate signals SGGu to SGGz are at substantially the same timing. Control so as not to switch. The gate signal SGGx is obtained by inverting the gate signal SGGu, the gate signal SGGy is obtained by inverting the gate signal SGGv, and the gate signal SGGz is obtained by inverting the gate signal SGGw.

(Embodiment 2)
In the power conversion device 10 according to the first embodiment, the on / off switching of the reverse conducting semiconductor switches SWU to SWZ is soft switching, but the on / off switching of the reverse conducting semiconductor switches SWu to SWz is performed. There was a possibility that soft switching would not occur.
In the power conversion device 20 according to the present embodiment, switching of the reverse conducting semiconductor switches SWu to SWz is also soft switching.

  The power conversion device 20 according to the present embodiment is configured such that the pulse pattern of the gate signals SGGu to SGGz of the power conversion device 10 of the first embodiment immediately before the timing at which the gate signals SGGU to SGGZ are switched from the on signal to the off signal. It is set in advance so as to switch the off signal. Other configurations are the same as those of the power conversion apparatus 10.

As described above, immediately before the gate signals SGGU to SGGZ are switched from the on signal to the off signal (t3 in FIG. 5), the voltage Vcm of the capacitor CM is substantially zero.
Therefore, soft switching is realized by setting a pulse pattern so as to switch the on signal / off signal of the gate signals SGGu to SGGz immediately before the timing at which the gate signals SGGU to SGGZ are switched from the on signal to the off signal.

The relationship between the gate signal SGGu set in this way and the voltage Vcm of the capacitor CM is as shown in FIG.
FIG. 9A shows an outline of the resonance voltage generated in the capacitor CM, and FIG. 9B shows the voltage Vcm of the capacitor CM.

By setting a pulse pattern so as to switch the on signal / off signal of the gate signals SGGu to SGGz immediately before the timing at which the gate signals SGGU to SGGZ are switched from the on signal to the off signal, FIG. 9A and FIG. ), The on / off signal of the pulse pattern is switched at the timing when the voltage of the capacitor CM is substantially zero.
Thereby, soft switching is realized in the DC / AC converter circuit 200.

(Embodiment 3)
In the first and second embodiments, the example in which the ON signal and the OFF signal of the gate signals SGGu, SGGv, SGGw, SGGx, SGGy, and SGGz are switched according to a preset pulse pattern has been described.
However, the gate signals SGGu, SGGv, SGGw, SGGx, SGGy, and SGGz may be controlled not by a pulse pattern but by a normal PWM (Pulse Width Modulation).

  In the power conversion device 30 according to the present embodiment, the control circuit 300 of the power conversion device 10 controls the gate signals SGGu to SGGz not by a pulse pattern but by normal PWM control.

The control circuit 300 determines gate signals SGGu to SGGw, for example, by comparing a preset target waveform with a triangular wave having a preset PWM frequency. In addition, the control circuit 300 sets the gate signal SGGx in the opposite phase to the gate signal SGGu, the gate signal SGGy in the opposite phase to the gate signal SGGv, and the gate signal SGGz in the opposite phase to the gate signal SGGw.
Thereby, the DC voltage generated in the capacitor CM is supplied to the inductive loads LD1 to LD3 by PWM control.

  In addition, the control circuit 300 controls the gate signals SGGu to SGGw so that a plurality of the gate signals SGGu to SGGw are not simultaneously switched from the on signal to the off signal. For example, when one of the gate signals SGGu to SGGw is switched from an on signal to an off signal, the control circuit 300 does not switch the other two gate signals during the next PWM period. As a result, a plurality of the reverse conducting semiconductor switches SWu to SWw are not switched from on to off. Further, since the gate signal SGGx is in reverse phase with respect to the gate signal SGGu, the gate signal SGGy is in reverse phase with respect to the gate signal SGGv, and the gate signal SGGz is in reverse phase with respect to the gate signal SGGw, the reverse conducting semiconductor A plurality of switches SWx to SWz are not switched from off to on.

  By controlling as described above, the fluctuation of the peak value of the voltage Vcm of the capacitor CM is reduced.

  In the embodiment described above, the gate signals SGGu to SGGw are controlled so that a plurality of the gate signals SGGu to SGGw are not simultaneously switched from the on signal to the off signal. However, a plurality of gate signals SGGx to SGGz may be controlled so as not to be simultaneously switched from an off signal to an on signal, or a plurality of gate signals SGGu to SGGw may not be simultaneously switched from an on signal to an off signal. In addition, a plurality of gate signals SGGx to SGGz may be controlled so as not to simultaneously switch from the off signal to the on signal.

(Embodiment 4)
In the third embodiment, the control circuit 300 controls the gate signals SGGu to SGGz by PWM control. However, if only PWM control is performed, there is a possibility that the reverse conducting semiconductor switches SWu to SWz are switched when a voltage is generated in the capacitor CM. In this case, hard switching is performed, and power consumption for switching is not small.

  The power conversion device 40 according to the present embodiment is configured to switch on / off of the reverse conduction semiconductor switches SWu to SWz of the DC / AC conversion circuit 200 by PWM control and soft switching in the power conversion device 30.

  In the power conversion device 40, the control circuit 300 waits until the switching timing of the gate signals SGGU to SGGZ at the timing of switching on / off of the reverse conducting semiconductor switches SWu to SWz in the PWM control, and before switching the gate signals SGGU to SGGZ. Further, the on signal and the off signal of the gate signals SGGu to SGGz are switched. The control circuit 300 repeats this operation.

  Next, operation | movement of this power converter device 40 is demonstrated.

The control circuit 300 determines the timing for switching on / off of the reverse conducting semiconductor switches SWu to SWz in the PWM control. However, at this time, the ON / OFF signals of the gate signals SGGu to SGGWz are not switched. At this timing, there is a possibility that a voltage is applied to the capacitor CM.
Thereafter, when it is time to switch the gate signals SGGU to SGGZ, the control circuit 300 switches the on signal / off signal of the gate signals SGGu to SGGz before switching the on signal / off signal of the gate signals SGGU to SGGZ.
At the timing of switching the gate signals SGGU to SGGZ, as described above, since the voltage Vcm of the capacitor CM is substantially 0, the reverse conduction type semiconductor switches SWu to SWz by switching the on signal / off signal of the gate signals SGGu to SGGz. On / off switching is soft switching.
By repeating this operation, the reverse conduction semiconductor switches SWu to SWz are turned on and off at the timing when the voltage of the capacitor CM is substantially 0, so that soft switching is realized.

The relationship between the gate signals SGGu to SGGz output by this control and the voltage Vcm of the capacitor CM is, for example, as shown in FIG.
10A shows the voltage Vcm of the capacitor CM, FIG. 10B shows the gate signal SGGu determined only by PWM control, and FIG. 10C shows the gate signal SGGu controlled to be soft switching. Indicates.

In the present embodiment, as shown in FIGS. 10B and 10C, the control circuit 300 has the gate signal SGGu at the timing of switching on / off of the reverse conducting semiconductor switches SWu to SWz in the PWM control. Do not switch. After this timing, the control circuit 300 turns on the gate signals SGGu to SGGz before switching the on signal / off signal of the gate signals SGGU to SGGZ at the timing of switching the on signal / off signal of the gate signals SGGU to SGGZ. Switches between signal and off signal.
In this case, when the voltage of the capacitor CM is substantially 0 as shown in FIG. 10A, the ON signal / OFF signal of the gate signal SGGu is switched as shown in FIG. Therefore, soft switching is realized also in the switching of the reverse conducting semiconductor switches SWu to SWz.

(Embodiment 5)
In the power converters 20 and 40 of the second and fourth embodiments, the DC / AC converter circuit 200 may be switched when the voltage Vcm of the capacitor CM is detected and the value of the voltage Vcm is substantially zero.
For example, as shown in FIG. 11, the voltage of the capacitor CM is detected by the voltage detector VM, and the control circuit 300 performs the gate signals SGGu through Switches on / off signal of SGGz.

  Accordingly, since the on / off of the reverse conducting semiconductor switches SWu to SWz is switched at the timing when the voltage of the capacitor CM is substantially 0, soft switching is realized.

(Embodiment 6)
In the power converter 10, a single-phase full-bridge MERS 110 may be used instead of the three-phase bridge MERS 100 as shown in FIG. The full bridge type MERS 110 includes DC output terminals DT1 and DT2, AC input terminals AT1 and AT2, reverse conducting semiconductor switches SW1 to SW4, and a capacitor CM.
The reverse conducting semiconductor switches SW1 to SW4 are composed of switch units S1 to S4 and diode units D1 to D4 connected in parallel to the switch units S1 to S4. The reverse conducting semiconductor switches SW1 to SW4 are, for example, power MOSFETs.

  A series circuit of an AC voltage source VS4 and a reactor Lac4 is connected between the AC input terminals AT1 and AT2. The DC input terminal DC + of the DC / AC converter circuit 200 is connected to the DC output terminal DT1, and the DC output terminal DT2 is connected to the DC output terminal DT2. A DC input terminal DC− of the AC conversion circuit 200 is connected.

  The reverse conducting semiconductor switches SW1 to SW4 are connected to the AC input terminal AT1 to the anode of the diode part D1 and the cathode of the diode part D2, and to the DC output terminal DT1 to the cathode of the diode part D1, the cathode of the diode part D3, and the capacitor CM. Is connected to the DC output terminal DT2, the anode of the diode part D2, the anode of the diode part D4, and the negative electrode of the capacitor CM, and the anode of the diode part D3 and the cathode of the diode part D4 are connected to the AC input terminal AT2. Is done.

  The control circuit 300 turns on and off the reverse conducting semiconductor switches SW2 and SW3 when the voltage output from the AC voltage source VS4 is positive, and turns on and off the reverse conducting semiconductor switches SW1 and SW4 when negative. Control.

In the case of the present embodiment, the reactor Lac4 and the capacitor CM resonate, so that a pulsed voltage Vcm is repeatedly generated in the capacitor CM. Therefore, it is preferable that the on / off periods of the reverse conducting semiconductor switches SW1 to SW4 are longer than the resonance period determined by the capacitance of the capacitor CM and the inductance of the reactor Lac4.
DC power is converted into AC power corresponding to ON / OFF of the reverse conduction type semiconductor switches SWu to SWz via the DC / AC conversion circuit 200 using the capacitor CM generating the DC voltage Vcm as a DC voltage source. And supplied to the induction raw loads LD1 to LD3.

  Thereby, an alternating current can be supplied from the alternating voltage source to each phase of the three-phase inductive load.

  As described above, according to the present invention, an AC current having a desired frequency can be obtained from an AC power source with a low loss, and a resonance voltage with a small peak value fluctuation can be applied to a load.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation and application are possible.

  For example, in the above embodiment, the reverse conducting semiconductor switches SWU to SWZ and SWu to SWz are described as self-extinguishing elements (N-channel MOSFETs) having parasitic diodes. However, the reverse conduction type semiconductor switches SWU to SWZ, SWu to SWz may be any reverse conductivity type switch, and are a field effect transistor, an insulated gate bipolar transistor (IGBT), a gate turn-off thyristor (GTO). : A self-extinguishing element such as Gate Turn-Off thyristor) or a combination of a diode and a self-extinguishing element.

  Further, it has been described that the control circuit 300 controls the ON / OFF of the reverse conducting semiconductor switches SWU to SWZ with the gate signals SGGU to SGGZ having a preset frequency and duty ratio as shown in FIG. However, the gate signals SGGU to SGGZ are not limited to those described above. For example, only one pair or two pairs of reverse conducting semiconductor switches SWU and SWX, reverse conducting semiconductor switches SWV and SWY, and reverse conducting semiconductor switches SWW and SWZ You may control. For example, PWM control may be performed without making the duty ratio constant, or the gate signals SGGU to SGGZ may be controlled so as to improve the power factor by PFC (Power Factor Correction).

The control circuit 300 has been described as a circuit that performs the above-described control. Or a computer such as a controller.
In this case, for example, a program for outputting the above-described gate signal may be stored in the ROM in advance.

  Also, even if the amount of power supplied to the inductive loads LD1, LD2, and LD3 is adjusted by storing in advance a plurality of pulse patterns for controlling the gate signals SGGu to SGGz and selecting a pulse pattern corresponding to a user instruction, for example. Good.

10, 20, 30, 40 Power converter 21 Three-phase AC power supply VS1, VS2, VS3, VS4 AC voltage sources LD1, LD2, LD3 Inductive loads Lac1, Lac2, Lac3, Lac4 Reactor 100 Three-phase bridge type MERS
110 Full-bridge MERS
200 DC / AC converter circuits AC1, AC2, AC3, AT1, AT2 AC input terminals DCP, DCN, DT1, DT2 DC output terminals DC +, DC− DC input terminals ACu, ACv, ACw AC output terminals SWU, SWV, SWW, SWX, SWY, SWZ, SWu, SWv, SWw, SWx, SWy, SWz, SW1, SW2, SW3, SW4 Reverse conducting semiconductor switch CM capacitors SU, SV, SW, SX, SY, SZ, Su, Sv, Sw, Sx, Sy, Sz, S1, S2, S3, S4 Switch unit DU, DV, DW, DX, DY, DZ, Du, Dv, Dw, Dx, Dy, Dz, D1, D2, D3, D4 Diode unit GU, GV, GW, GX, GY, GZ, Gu, Gv, Gw, Gx, Gy, Gz, G1, G2, G3, G4 Gate SGGU, SG GV, SGGW, SGGX, SGGY, SGGZ, SGGu, SGGv, SGGw, SGGx, SGGy, SGGz, SGG1, SGG2, SGG3, SGG4 Gate signal

Claims (16)

A reactor that stores electric power supplied from an AC power source as magnetic energy;
A magnetic energy regenerative switch that includes a capacitor, recovers the magnetic energy of the reactor, and stores the energy in the capacitor as electrostatic energy;
A first DC input terminal connected to one pole of the capacitor; a second DC input terminal connected to the other pole of the capacitor; and a first DC input terminal connected to each phase of a three-phase inductive load. 1 to 3rd AC output terminals, 1st to 6th diodes, and 1st to 6th self-extinguishing elements, and the first DC input terminal includes the first diode. The cathode of the third diode, the cathode of the fifth diode, and the cathode of the fifth diode are connected to the second DC input terminal at the anode of the second diode, the anode of the fourth diode, and the sixth diode. The anode of the diode is connected, the anode of the first diode and the cathode of the second diode are connected to the first AC output terminal, and the third diode is connected to the second AC output terminal. Anode and said And the third AC output terminal is connected to the anode of the fifth diode and the cathode of the sixth diode, and the first diode is connected to the first self-extinguishing element. The second self-extinguishing element is provided in the second diode, the third self-extinguishing element is provided in the third diode, and the fourth self-extinguishing type is provided in the fourth diode. The fifth diode is connected to the fifth self-extinguishing element, the sixth diode is connected to the sixth self-extinguishing element in parallel, and the first to sixth self-extinguishing elements are connected in parallel. A DC / AC conversion circuit that outputs a DC voltage generated in the capacitor to the inductive load from the first to third AC output terminals in response to ON / OFF of the arc-extinguishing element;
Control means for controlling on / off of the first to sixth self-extinguishing elements;
With
The control means controls on / off of the first to sixth self-extinguishing elements so that a plurality of on / off of the first to sixth self-extinguishing elements are not switched at substantially the same timing. To
The power converter characterized by the above-mentioned. The control means is configured so that the third to sixth self-extinguishing elements are not switched on and off at substantially the same timing when the first self-extinguishing elements are switched on and off. The third self-extinguishing element is turned on and off so that the third to sixth self-extinguishing elements are not turned on and off at substantially the same timing when the self-extinguishing element is turned on and off. The fourth self-extinguishing element is turned on / off so that the first, second, fifth, and sixth self-extinguishing elements are not turned on and off at substantially the same timing at which The fifth self-extinguishing element is switched on / off so that the first, second, fifth, and sixth self-extinguishing elements are not switched on and off at substantially the same timing. The first to fourth at substantially the same timing. The first to fourth self-extinguishing elements are turned on / off at substantially the same timing at which the sixth self-extinguishing element is turned on / off so that the self-extinguishing element is not turned on / off. Controlling on / off of the first to sixth self-extinguishing elements so as not to switch.
The power conversion apparatus according to claim 1. The DC voltage generated in the capacitor is a pulsed DC voltage.
The power conversion device according to claim 1 or 2, wherein The control means switches on / off of the first to sixth self-extinguishing elements when the voltage of the capacitor is substantially zero.
The power conversion device according to claim 1, wherein the power conversion device is a power conversion device. The control means does not turn on both the first and fourth self-extinguishing elements, does not turn on both the second and fifth self-extinguishing elements, and controls the third and sixth Controlling the first to sixth self-extinguishing elements so that both of the self-extinguishing elements are not turned on;
The power conversion device according to claim 1, wherein the power conversion device is a power conversion device. The control means controls on / off of the first to sixth self-extinguishing elements by a pulse pattern;
The power conversion device according to any one of claims 1 to 5, wherein: The control means controls on / off of the first to sixth self-extinguishing elements by pulse width modulation.
The power conversion device according to claim 1, wherein the power conversion device is a power conversion device. The AC power supply is a three-phase AC power supply,
The reactor includes a first reactor having one end connected to the first phase of the three-phase AC power source, a second reactor having one end connected to the second phase, and a third reactor having one end connected to the third phase. Consisting of
The magnetic energy regeneration switch includes first to third AC input terminals, first and second DC output terminals, seventh to twelfth diodes, seventh to twelfth self-extinguishing elements, , A capacitor, and the first AC input terminal includes the other end of the first reactor, the anode of the seventh diode, and the cathode of the eighth diode at the second AC input terminal. The other end of the second reactor, the anode of the ninth diode, and the cathode of the tenth diode are connected to the third AC input terminal and the other end of the third reactor and the eleventh electrode. The anode of the diode and the cathode of the twelfth diode are connected, and the first DC output terminal has a cathode of the seventh diode, a cathode of the ninth diode, and the eleventh die. The cathode of the first electrode and one pole of the capacitor are connected to the second DC output terminal of the anode of the eighth diode, the anode of the tenth diode, the anode of the twelfth diode, and the capacitor. The other electrode is connected, the seventh self-extinguishing element is connected to the seventh diode, the eighth self-extinguishing element is connected to the eighth diode, and the ninth diode is connected to the ninth diode. A ninth self-extinguishing element is provided in the tenth diode, the tenth self-extinguishing element is provided in the eleventh diode, and the eleventh self-extinguishing element is provided in the twelfth diode. The twelfth self-extinguishing element is a three-phase bridge magnetic energy regenerative switch connected in parallel;
The control means controls on / off of the first to twelfth self-extinguishing elements.
The power conversion device according to claim 1, wherein the power conversion device is a power conversion device. The voltage of the capacitor immediately before the seventh to twelfth self-extinguishing elements change from off to on is substantially zero.
The power conversion device according to claim 8. Immediately before the seventh to twelfth self-extinguishing elements change from off to on, the current flowing through the seventh to twelfth self-extinguishing elements is substantially zero.
The power conversion device according to claim 8 or 9, characterized in that. The control means, when the output of the first phase of the three-phase AC power supply is positive, repeatedly switches the seventh self-extinguishing element and holds the eighth self-extinguishing element off, When the output of the first phase is negative, the eighth self-extinguishing element is repeatedly switched on and off, and the seventh self-extinguishing element is held off. If positive, the ninth self-extinguishing element is repeatedly switched and the tenth self-extinguishing element is held off, and if the second phase output is negative, the tenth self-extinguishing element is turned off. Repeatedly switching on and off the arc-extinguishing element and holding the ninth self-extinguishing element off, and repeatedly switching the eleventh self-extinguishing element when the third phase output is positive; The twelfth self-extinguishing element is held off, and the third phase output is negative. Is to be held in the twelfth repeated switching on and off of the self-extinguishing type switching elements, and the first 11 off the self extinguishing type switching elements of,
The power conversion device according to any one of claims 8 to 10, wherein: The magnetic energy regeneration switch includes a first AC input terminal, a second AC input terminal in which a series circuit of the AC power source and a reactor is connected between the first AC input terminal, a first and a first Two DC output terminals, a capacitor connected between the first and second DC output terminals, seventh to tenth diodes, and seventh to tenth self-extinguishing elements. The first AC input terminal has an anode of the seventh diode and the cathode of the eighth diode, and the second AC input terminal has an anode of the ninth diode and the tenth diode. The cathode of the seventh diode and the cathode of the ninth diode are connected to the first DC output terminal, and the eighth diode is connected to the second DC output terminal. The anode and The anode of the tenth diode is connected to the seventh diode, the seventh self-extinguishing element is connected to the seventh diode, and the eighth self-extinguishing element is connected to the eighth diode. A full-bridge magnetic energy regenerative switch in which the ninth self-extinguishing element and the tenth self-extinguishing element are connected in parallel to the diode,
The control means controls on / off of the first to tenth self-extinguishing elements;
The power conversion device according to claim 1, wherein the power conversion device is a power conversion device. The voltage of the capacitor immediately before the seventh to tenth reverse conducting semiconductors change from off to on is substantially zero.
The power conversion device according to claim 12, wherein Immediately before the seventh to tenth reverse conducting semiconductors change from off to on, the current flowing through the seventh to tenth reverse conducting semiconductor switches is substantially zero.
The power conversion device according to claim 12 or 13, characterized by the above. The control means repeatedly switches the eighth and ninth self-extinguishing elements and keeps the seventh and tenth self-extinguishing elements off when the output voltage of the AC power supply is positive. When the output voltage is negative, the seventh and tenth self-extinguishing elements are repeatedly switched on and off and the eighth and ninth self-extinguishing elements are held off.
The power conversion device according to claim 12, wherein the power conversion device is a power conversion device. A reactor that stores electric power supplied from an AC power source as magnetic energy;
A magnetic energy regenerative switch that includes a capacitor, recovers the magnetic energy of the reactor, and stores the energy in the capacitor as electrostatic energy;
A first DC input terminal connected to one pole of the capacitor; a second DC input terminal connected to the other pole of the capacitor; and a first DC input terminal connected to each phase of a three-phase inductive load. 1 to 3rd AC output terminals, 1st to 6th diodes, and 1st to 6th self-extinguishing elements, and the first DC input terminal includes the first diode. The cathode of the third diode, the cathode of the fifth diode, and the cathode of the fifth diode are connected to the second DC input terminal at the anode of the second diode, the anode of the fourth diode, and the sixth diode. The anode of the diode is connected, the anode of the first diode and the cathode of the second diode are connected to the first AC output terminal, and the third diode is connected to the second AC output terminal. Anode and said And the third AC output terminal is connected to the anode of the fifth diode and the cathode of the sixth diode, and the first diode is connected to the first self-extinguishing element. The second self-extinguishing element is provided in the second diode, the third self-extinguishing element is provided in the third diode, and the fourth self-extinguishing type is provided in the fourth diode. The fifth diode is connected to the fifth self-extinguishing element, the sixth diode is connected to the sixth self-extinguishing element in parallel, and the first to sixth self-extinguishing elements are connected in parallel. A DC / AC conversion circuit that converts a DC voltage generated in the capacitor into an AC voltage and applies it to the inductive load corresponding to on / off of the arc-extinguishing type element; and
A control method for controlling on / off of the first to sixth self-extinguishing elements in a power conversion device comprising:
Controlling on / off of the first to sixth self-extinguishing elements so that a plurality of on / off of the first to sixth self-extinguishing elements are not switched at substantially the same timing;
A control method characterized by that.

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