JP5885073B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device including an inverter circuit that converts DC power into AC power. In particular, the present invention relates to a power conversion apparatus configured to be capable of operating a plurality of inverter circuits in parallel.

  Conventionally, as an apparatus for converting DC power output from a DC power source into AC, a power converter as disclosed in Patent Document 1 has been used. This power conversion device converts a DC voltage into an AC power by turning on / off a switching element.

  By the way, there is a method of increasing the capacity of the switching element itself as a method corresponding to the increase in capacity of such a power conversion device. However, there is a limit to the capacity that can be applied to the switching element used in the power conversion device, and this method cannot be applied to increase the capacity that exceeds the capacity that the switching element can handle. Then, like this patent document 1, the power converter device respond | corresponds to large capacity | capacitance by carrying out the parallel operation of several power converter devices.

  This power conversion device includes two inverter circuits that convert DC power into three-phase AC power, a combined reactor that couples these two inverter circuits for each phase, and an output current that is output from these two inverter circuits And a calculation unit for calculating the output currents of these two inverter circuits based on the detection current detected from the current detection circuit.

  However, when the inverter circuits are connected in parallel and operated, the balance of the output currents output from the inverter circuits may be lost due to the output voltage output from each inverter circuit or a phase shift. In such a case, all output currents output from all inverter circuits are not output to the load, and a part of current output from one inverter circuit is output to the other inverter circuit. The current flowing from one inverter circuit to the other inverter circuit is generally called a cross current. This cross current is not used as an output current, but also acts to cancel the current output by the other inverter circuit, thereby reducing the output current. Therefore, this cross current is a cause of reducing the efficiency of the entire power converter. Therefore, in order to suppress the current flowing between the inverter circuits and reduce the cross current, a coupling reactor is provided between the inverter circuits.

  Further, as an output current detection method for detecting an output current of a symmetrical three-phase alternating current method output from one inverter circuit, as described in Patent Document 2, among the three-phase output currents constituting the inverter circuit There is a method in which a two-phase output current is detected by a current detection unit, and an undetected one-phase output current is calculated from a two-phase detection current detected by the current detection unit. This output current detection method uses the law that the result of combining the output currents of the respective phases of the inverter circuit becomes zero, and is a general method for detecting the output current of one inverter circuit.

  Therefore, in a power conversion device in which a plurality of inverter circuits as in Patent Document 1 are operated in parallel, when the output current is detected and controlled by the output current detection method as in Patent Document 2, the current detection unit is The three-phase output currents constituting the inverter circuit are provided for the two-phase output currents, and the three-phase output currents constituting the other inverter circuit are provided for the two-phase output currents. And a calculating part calculates | requires the output current of 1 phase which is not detected for each inverter circuit by calculation based on the detected current which these current detection parts detected.

International Publication No. 95/24069 Japanese Patent Laid-Open No. 9-23671

  The output current thus determined is treated as a control amount for controlling each inverter circuit so as to balance between these inverter circuits, but the current detection unit does not directly detect the output current. Therefore, an algorithm for adjusting the balance of the output current between the inverter circuits is required separately, which is extremely difficult to realize.

  In order to improve this, even if the output current of all three phases constituting each inverter circuit is detected by the current detection unit and each inverter circuit is controlled, the ripple current or detection error included in principle is caused. In the symmetrical three-phase alternating current system, the law that the result of combining the output currents of the respective phases becomes zero is not satisfied. In the power conversion device, the output current is controlled based on the law that the result of synthesizing the output current of each phase constituting the inverter circuit becomes zero. Therefore, this law is not satisfied due to the influence of this detection error. , Control becomes unstable.

  Therefore, in view of such circumstances, the present invention provides a power converter that can calculate each output current in accordance with the law that the result of synthesizing the output currents of the respective phases constituting the inverter circuit is zero. And

  The power conversion device according to the present invention includes two or more inverter circuits that convert DC power into polyphase AC power, a current detection circuit that detects an output current output from the two or more inverter circuits, and the current And a control unit that controls output currents of the two or more inverter circuits based on a detection current detected from the detection circuit, wherein the current detection circuit includes the two or more inverter circuits. A current detection unit that detects the output current of the remaining phases excluding one phase that does not detect the output current among the output phases is provided, and the control unit combines the detection currents detected by the current detection unit A current calculation unit that determines, by calculation, an output current of one phase that is not detected by the current detection unit, so that a combined current of output currents of all phases becomes zero based on the combined current To.

  According to such a configuration, the current calculation unit calculates a one-phase output current that is not detected by the current detection unit so that a combined current obtained by combining the output currents of all phases becomes zero. In other words, the current calculation unit causes the current detection unit to generate a fault current that obstructs the establishment of the law that the result of combining the output current of each phase in the inverter circuit becomes zero due to a cross current or a detection error. Calculation is made so that it is included in the output current of one phase that is not detected. Therefore, this law is established. In this way, the output current of one phase among the output currents of all phases in the two or more inverter circuits can be obtained by calculating with the current calculation unit without detecting with the current detection unit. In addition, since the current detection circuit can reduce the current detection unit for one phase, the power conversion device can be made cheaper than when a current detection unit is provided for each phase.

  The power converter according to the present invention includes two inverter circuits that convert DC power into three-phase AC power, a current detection circuit that detects an output current output from the two inverter circuits, and the current detection circuit. And a control unit that controls the output currents of the two inverter circuits based on the detected current detected from the two inverter circuits, wherein the current detection circuit is a six-phase output from the two inverter circuits. Among them, a current detection unit that detects the remaining five-phase output current except one phase that does not detect the output current is provided, and the control unit combines the five-phase detection currents detected by the current detection unit. A current calculation unit is provided that determines, by calculation, one-phase output current that is not detected by the current detection unit, so that the combined current of all six-phase output currents becomes zero based on the combined current. To.

  According to such a configuration, one-phase output current out of the six-phase output currents output from the two inverter circuits can be obtained by calculating with the current calculation unit without directly detecting with the current detection unit. Therefore, since the current detection circuit can reduce the current detection unit for one phase, the power conversion device can be made cheaper than in the case where a current detection unit is provided for each phase.

  As described above, according to the power conversion device of the present invention, the excellent effect that each output current can be calculated according to the law that the result of combining the output currents of the respective phases constituting the inverter circuit becomes zero. Play.

FIG. 1 is an overall circuit diagram of an inverter circuit according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a control unit of the inverter circuit according to the embodiment. FIG. 3 is a block diagram illustrating a control unit of an inverter circuit according to another embodiment.

  A power converter according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. First, the configuration of the power conversion device 1 according to the embodiment will be described.

As shown in FIG. 1, the power conversion device 1 includes an AC power source 2 that supplies three-phase AC power, one or more three-phase AC loads 3, and a target output current that is supplied to the load 3. 1 is connected to a target output current command unit 4 for commanding 1. The target output current is composed of a d-axis target output current I _d _ _ref and a q-axis target output current I _q _ _{ref obtained} by dq coordinate conversion of the output current output from the power converter 1 (see FIG. 2). .

The power conversion apparatus 1 includes two or more power conversion units 10 and 11 that convert AC power input from an AC power supply 2, a combined reactor 12 that couples the power conversion units 10 and 11, and a power conversion unit 10. , 11 output current I _u1 , I _v1 , I _w1 , I _u2 , I _v2 , I _w2 (hereinafter abbreviated as “I _u1,. Circuit 13 and detection currents I _{u1 — det} , I _{v1 — det} , I _{w1 — det} , I _{u2 — det} , I _{w2 — det} (hereinafter referred to as “I _{u1 — det ,.} And a control unit 14 for controlling the output currents I _u1,. In the present embodiment, an example in which there are two power conversion units 10 and 11 will be described. Therefore, in the present specification, these power conversion units are referred to as “first and second power conversion units 10 and 11”.

  The first power conversion unit 10 includes a rectifier circuit 100 that rectifies AC power input from the AC power supply 2, a smoothing circuit 101 that smoothes DC power output from the rectifier circuit 100, and the smoothing circuit. And a first inverter circuit 102 that converts the DC power input from 101 into multiphase AC power.

  The second power conversion unit 11 includes a smoothing circuit 110 that smoothes the DC power output from the rectifier circuit 100, and a second power that converts the DC power input from the smoothing circuit 110 into multiphase AC power. And an inverter circuit 111.

  The rectifier circuit 100 converts AC power input from the AC power source 2 into DC power using a rectifying element that rectifies AC power. The rectifier circuit 100 rectifies by combining a plurality of rectifier diodes. Note that the rectifier circuit 100 may be a control rectifier circuit that performs rectification by switching the switching element.

  The smoothing circuits 101 and 110 attenuate and smooth the switching ripple included in the input voltage input from the rectifier circuit 100. The smoothing circuits 101 and 110 are smoothing capacitors connected in parallel to the output side of the rectifier circuit 100. This smoothing capacitor is specifically an electrolytic capacitor.

  The first and second inverter circuits 102 and 111 convert the DC power input from the rectifier circuit 100 into AC power. These inverter circuits 102 and 111 convert the output voltage based on the PWM signal input from the target output current command unit 4 to the gate.

  The coupling reactor 12 combines the output phases output from the inverter circuits 102 and 111 of the first and second power conversion units 10 and 11. The coupling reactor 12 connects output phases common to the inverter circuits 102 and 111 via the reactor. The combined reactor 12 divides the voltage difference between the output voltages output from the first and second power conversion units 10 and 11 by this reactor and flows between the first and second power conversion units 10 and 11. Suppresses the cross current.

The current detection circuit 13 outputs the output currents I _u1 ,..., I _{u2 of} the remaining phases excluding one phase that does not detect the output current among the output phases output from the first and second power conversion units 10 and 11. , I _w2 are provided. The detection currents I _u1 _ _det ,... Detected by the current detection circuit 13 are all u1 phase, v1 phase and w1 phase output currents I _u1 , I _v1 , I _w1 on the output side of the first inverter circuit 102. The output currents I _u2 and I _{w2 of the} u2 phase and the w2 phase excluding the v2 phase on the output side of the second inverter circuit 111 are detected. That is, the current detection circuit 13 includes five-phase output currents I _u1 ,..., I _u2 , I _w2 among the six-phase output currents I _u1 ,... Output from the first and second power conversion units 10 and 11. Is a circuit for detecting The current detection circuit 13 does not detect the v2-phase output current I _v2 on the output side of the second inverter circuit 111. The v2-phase output current I _v2 is obtained by calculation in the control unit 14.

  The current detection units 130 to 134 are instrument transformers that convert a primary current into a secondary current proportional thereto and output the secondary current. The current detection units 130 to 134 have a structure that is independently attached to each output phase. That is, one current detector 130 to 134 is attached per output phase to be detected.

As shown in FIG. 1, the control unit 14 sets a target output current input unit 140 to which a target output current is input from the target output current command unit 4 and a target output current input from the target output current input unit 140. The target output current dividing unit 141 that divides the power conversion units 10 and 11, the detection current input units 142 and 143 that receive the detection currents I _u1 _ _det ,... From the current detection circuit 13, and the current detection circuit 13. Current calculation unit 144 that calculates the output current I _v2 that is not, and first to first feedback control that outputs the target output current from the power conversion units 10 and 11 based on the detection currents I _{u1 — det ,.} 3 to determine the duty ratio of the PWM control based on the compensation amounts of the feedback control units 145 to 147 and the first to third feedback control units 145 to 147. And a PWM control unit 148, 149 for driving and controlling the respective inverter circuits 102 and 111 based on the ratio.

  The target output current input unit 140 is an input interface that receives the target output current from the target output current command unit 4.

  The target output current dividing unit 141 is a divider that divides the received target output current by the number divided by the inverter circuits 102 and 111. The first and second inverter circuits 102 and 111 have the same capacity and two. Therefore, the target output current dividing unit 141 divides the target output current by 2 so that the target output current is equally divided with respect to the first and second inverter circuits 102 and 111.

Detecting current input 142 and 143, the output current I _u1 from the current detection circuit 13, ..., I _u2, detection of the detection phase is detecting the I _w2 current I _u1 _ _det, is an input interface for accepting .... One detection current input unit 142 detects detection currents I _u1 _ _det and I _v1 _ _det detected from the detection phase consisting of the u1 phase, the v1 phase, and the w1 phase on the first power conversion unit 10 side from the current detection circuit 13. , I _{w1 — det} is input. The other detection current input unit 143 receives the detection currents I _u2 _ _det and I _w2 _ _det detected from the detection phase composed of the u2 phase and the w2 phase on the second power conversion unit 11 side from the current detection circuit 13. The In the present specification, one detection current input unit 142 is referred to as a “first detection current input unit 142”, and the other detection current input unit 143 is referred to as a “second detection current input unit 143”.

The current calculation unit 144 is based on the combined detection current obtained by combining the detection currents I _{u1 — det} ,... Of the detection phase, so that the combined current of the output currents I _u1,. The output current I _v2 that is not detected in ~ 134 is calculated.

Current calculation unit 144, a first adder for adding the detected current I _u1 _ _det of all phases of the output of the first inverter circuit 102, I _v1 _ _det, the I _w1 _ _det as a first summing detection current The first detection current I _u2 _ _det , I _w2 _ _det and the first addition detection current of all phases detected on the output side of the second inverter circuit 111 are added as the second addition detection current. 2 and an adder 1441, and a sign converter 1442 that outputs a v2-phase operation current I _{u1 — cal} obtained by inverting the positive (+) sign or the negative (−) sign of the second addition detection current.

The first and second feedback control units 145 and 146 are provided corresponding to the first and second inverter circuits 102 and 111, respectively. The first and second feedback control units 145 and 146 calculate a compensation amount between the output currents I _u1 ,... Output from the first and second inverter circuits 102 and 111 and the target output current.

  The third feedback control unit 147 calculates the compensation amount of the second feedback control unit 146 so as to balance the compensation amounts calculated by the first feedback control unit 145 and the second feedback control unit 146.

The first and second PWM control units 148 and 149 are respectively connected to the gates of the first and second inverter circuits 102 and 111 with three-phase output voltages V _{u1 *} , V _{v1 *} , V _{w1 *} , V _{u2 **} , A PWM signal based on V _{v2 **} and V _{w2 **} is input.

  Next, the first to third feedback control units 145, 146, and 147 of the power conversion device 1 according to the embodiment will be described in detail with reference to the block diagram of FIG.

  First, the first and second feedback control units 145 and 146 are connected to the target output current input unit 140 via the target output current dividing unit 141. The target output current divided by the target output current dividing unit 141 is input from the target output current input unit 140 to each of the first and second feedback control units 145 and 146.

The first feedback control unit 145 further includes detection currents I _u1 _ _det and I _v1 _ detected from the u1 phase, the v1 phase, and the w1 phase of the first inverter circuit 102 from the first detection current input unit 142. _det and I _{w1 — det} are input. The first feedback control unit 145 includes a two-phase three-phase converter 1450 that performs coordinate conversion of the detected currents I _{u1 — det} , I _{v1 — det} , and I _{w1 — det} into the dq coordinate system, and a dq coordinate from the target output current. converted detected current _{I u1 _ det, I v1 _} det, I a subtracter 1451 for subtracting _w1 _ _det, PI controller for performing PI (proportional integral) control based on the error of the detected current from the target output current 1452 and a three-phase two-phase converter 1453 that converts the d-axis output voltage and the q-axis output voltage based on the PI controller 1452 into three-phase AC voltages V _{u1 *} , V _{v1 *} , V _{w1 *} .

The second feedback control unit 146 also receives detection currents I _u2 _ _det and I _w2 _ _det detected from the u2 phase and the w2 phase of the second inverter circuit 111 from the second detection current input unit 143. At the same time, the v2-phase calculation current I _{v1 — cal} calculated by the current calculation unit 144 is input. Then, the second feedback control unit 146 includes a two-phase three-phase converter 1460 that performs coordinate conversion of the detection currents I _{u2 — det} , I _{w2 — det} and the calculation current I _{v2 — cal} into the dq coordinate system, and a target output current. A subtractor 1461 for subtracting the detection currents I _u2 _ _det , I _w2 _ _det and the calculation current I _v2 _ _cal after the dq coordinate conversion, and PI (proportional integration) control based on the error of the detection current from the target output current A PI controller 1462 for performing, and a three-phase two-phase converter 1463 for converting the d-axis output voltage and the q-axis output voltage based on the PI controller 1462 into three-phase AC voltages V _{u2 *} , V _{v2 *} , V _{w2 *} Prepare.

The third feedback control unit 147 detects the detected currents I _u2 _ _det , I on the second inverter circuit 111 side from the detected currents I _u1 _ _det , I _v1 _ _det , I _w1 _ _det on the first inverter circuit 102 side. a subtracter 1470 for subtracting _w2 _ _det and operation current I _v2 _ _cal, based on the error of the second inverter circuit 111 side of the detected current from the detection current of the first inverter circuit 102 side PI (proportional integral) A PI controller 1471 that performs control, and a three-phase output voltage V _{u2 *} , V _{v2 *} , V _{w2 *} based on the PI controller 1471 to a three-phase output voltage V _{u2 **} , V based on the PI controller 1452, 1462 and an adder 1472 for adding _{v2 **} and _{Vw2 **} .

  Next, operation | movement of the power converter device 1 which concerns on the embodiment is demonstrated, referring FIG.1 and FIG.2.

First, as shown in FIG. 2, when the target output current input unit 140 of the control unit 14 receives the target output current from the target output current command unit 4, each of the inverter circuits 102 and 111 performs first and second power conversions. Drive control is performed so that a combined current of the output currents I _u1 ,... Of the units 10 and 11 becomes a target output current.

That is, the target output current input unit 140 inputs the d-axis target output current I _{d — ref} and the q-axis target output current I _{q — ref} of the received target output current to the target output current dividing unit 141. The target output current division section 141, the inputted d-axis target output current I _d _ a _ref and the q-axis target output current I _q _ _ref, the output current I _u1 between the first and second inverter circuits 102 and 111, Split so that… are balanced. Then, the target output current dividing unit 141 inputs the divided target output current to the subtracters 1451 and 1461 of the inverter circuits 102 and 111, respectively.

On the other hand, the current detection circuit 13 detects the detection currents I _{u1 — det} ,... Of the detection phases of the first and second inverter circuits 102 and 111. Then, the current detection units 130 to 134 input the detected detection currents I _u1 _ _det ,... To the first and second detection current input units 142 and 143.

First detection current input unit 142, the detected current I _u1 _ _det detected from the first inverter circuit 102, I _v1 _ _det, the I _w1 _ _det, the current calculator 144, the first and third feedback Input to the control units 145 and 147.

Second detection current input unit 143, the detected current I _u2 _ _det detected from the second inverter circuit 111, the I _w2 _ _det, the current calculator 144, the second and third feedback control unit 146, 147 And enter.

Current calculation section 144 adds the first detection current is input from the input unit 142 the detected current _{I u1 _ det, I v1 _} det, the I _w1 _ _det in the first adder 1440. Then, the current calculation unit 144 includes the first addition detection current added by the first adder 1440 and the detection currents I _u2 _ _det and I _w2 _ _det input from the second detection current input unit 143. Are added by the second adder 1441. The sign of the second addition detection current added by the second adder 1441 is inverted by the sign converter 1442. The second addition detection current with the sign inverted is the v2-phase operation current I _{v2 — cal} that was not detected by the current detection circuit 13.

The first and second feedback control units 145 and 146 convert the detected currents I _u1 _ _det ,... Of the detected inverter circuits 102 and 111 and the calculation current I _v2 _ _cal by three-phase two-phase converters 1450 and 1460, respectively. Two-phase dq coordinate transformation is performed for each. The subtracters 1451 and 1461 subtract the d-axis detection current and the q-axis detection current that have been converted from the dq coordinate from the d-axis target output current I _{d — ref} and the q-axis target output current I _{q — ref} . Then, the PI controllers 1452 and 1462 perform PI (proportional integration) control based on the error of the detected current from the target output current value. The three-phase to two-phase converters 1453 and 1463 convert the d-axis output voltage and q-axis output voltage output from the PI controllers 1452 and 1462 into three-phase AC voltages V _{u1 *} , V _{v1 *} , V _{w1 *} , V _u2. Convert to _** , V _{v2 **} , V _{w2 **} .

The third feedback control unit 147, the detected current I _u1 _ _det of the first inverter circuit 102, I _v1 _ _det, the detected current I _u2 _ _det from I _w1 _ _det second inverter circuit 111, I _w2 _ _The subtractor 1470 subtracts _det and the operation current I _{v2 — cal} . Then, the PI controller 1471 performs PI (proportional integration) control based on the error of the detection current of the second inverter circuit 111 from the detection current of the first inverter circuit 102. Then, the adder 1472 adds the output voltage output from the PI controller 1471 and the output voltages V _{u2 *} , V _{v2 *} , and V _{w2 *} as the compensation amounts output from the second feedback control unit 146.

The output voltages V _{u1 *} , V _{v1 *} , and V _{w1 *} as compensation amounts output from the first feedback control unit 145 are input to the first PWM control unit 148 to drive the first inverter circuit 102. Control. On the other hand, the output voltages V _{u2 **} , V _{v2 **} , and V _{w2 **} as compensation amounts output from the third feedback control unit 147 are input to the second PWM control unit 149, and the second inverter The circuit 111 is driven and controlled. Thus, the output current of the second inverter circuit 111 is drive-controlled so as to match the output current of the first inverter circuit 102.

In this way, the current calculation unit 144 calculates the one-phase output current I _v2 that is not detected by the current detection units 130 to 134 so that the combined current of the output currents I _u1 ,. . That is, the current calculation unit 144 synthesizes the output currents I _u1 ,... Of the respective phases u1,... In the first and second inverter circuits 102, 111 due to a cross current or an error current due to a detection error. Is calculated so as to be included in the one-phase output current I _v2 that is not detected by the current detectors 130 to 134. Therefore, this law is established.

  However, as in the prior art, the two-phase output current is detected among the three-phase output currents of the first and second inverter circuits 102 and 111, and the remaining output currents that are not detected are independently calculated. Therefore, this law is not established by the cross current and error current flowing between the first inverter circuit 102 and the second inverter circuit 111. Further, when all output currents of the first and second inverter circuits 102 and 111 are detected, this law is not established due to an error current.

In the power conversion device 1 according to the present embodiment, the law that the result of combining the output currents I _u1 ,... Of the respective phases u1, ... in the first and second inverter circuits 102, 111 is zero is established. Of the six-phase output currents I _u1 ,... Output from the two inverter circuits 102 and 111, the one-phase output current I _v2 is calculated by the current calculation unit 144 without being directly detected by the current detection units 130 to 134. Can be obtained. Moreover, since the current detection circuit 13 can reduce the current detection units 130 to 134 for one phase, the power conversion device 1 can be made cheaper than when the current detection units 130 to 134 are provided for each phase. can do.

  Further, even if the first and second inverter circuits 102 and 111 are operated alone, the third feedback control unit 147 matches the output currents output from the first and second inverter circuits 102 and 111. The PMW signal input to the gates of the first and second inverter circuits 102 and 111 is controlled. Therefore, the output currents output from the first and second inverter circuits 102 and 111 are balanced and controlled so that the output waveform does not collapse.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention.

  The power conversion device 1 according to the embodiment described above includes an example including a third feedback control unit 147 that compensates for the output current of the second inverter 111 using the three-phase alternating current of the first inverter circuit 102 as a target value. However, the present invention is not limited to this. For example, as shown in FIG. 3, the power conversion device includes third feedback control units 147A and 147B that compensate the output current of each inverter circuit using each three-phase alternating current as a target value for each inverter circuit. May be.

The third feedback control units 147A and 147B include three-phase two-phase converters 1470A and 1470B for converting the target output current into a three-phase alternating current, and the target output currents I _d _ _ref and I _q _ _ref after the coordinate conversion. Subtracter 1471 for subtracting the detected currents of the first and second inverter circuits 102 and 111 from the amplifier, amplifiers 1472A and 1472B for amplifying the error obtained by the subtractor 1471, and the error amplified by the amplifiers 1472A and 1472B Are added to the first and second feedback control units 146 and 147, respectively.

Unlike the first and second feedback control units 145 and 146, the third feedback control units 147A and 147B use the target output current obtained by converting the target output current commanded by the dq coordinate into a three-phase alternating current as a target value. The detection current I _{u1 — det} ,... And the calculation current I _{v2 — cal} are subtracted to obtain an error. The error is amplified by the amplifiers 1472A and 1472B and added to the compensation values of the first and second feedback control units 145 and 146.

  For this reason, even if the first and second inverter circuits 102 and 111 are operated alone, the output currents output from the first and second inverter circuits 102 and 111 by the third feedback control units 147A and 147B, respectively. The PMW signal input to the gates of the first and second inverter circuits 102 and 111 can be controlled so as to match. The output currents output from the first and second inverter circuits 102 and 111 are balanced and controlled so that the output waveform does not collapse.

  Although the power converter device 1 which concerns on the said embodiment demonstrated the example in which a some inverter carries out a parallel operation for the use corresponding to capacity increase, it is not limited to this use. For example, the power conversion device of the present invention is a duplex system that can maintain a constant power supply even when a part of the power conversion units breaks down by sharing and supplying loads by a plurality of power conversion units May be used.

  The power conversion device 1 according to the embodiment described above is an example in which the input AC power is rectified by a rectifier circuit, and the rectified DC power is converted to AC power, and is a circuit composed of a combination of a rectifier circuit and an inverter. However, the present invention is not limited to this. For example, the power conversion device may be an inverter that receives input of DC power and converts DC power to AC power.

  Although the power converter device 1 which concerns on the said embodiment demonstrated the example provided with two inverters 102 and 111 which convert direct-current power into three-phase alternating current power, it is not limited to this. For example, the inverter may be an inverter that converts multiphase AC power such as 6-phase or 12-phase. Further, the inverter may be two or more inverters. In that case, the current detection circuit includes current detection units in all phases except one phase among all phases output from all these inverters. Then, the output current value of the phase of the inverter not detected by the current detection unit is calculated by inverting the sign of the combined current obtained by combining all the current detection values detected from the current detection unit.

  The power conversion apparatus 1 according to the above embodiment describes an example in which DC power rectified from AC power 2 by the rectifier circuit 100 common to the inverter circuits 102 and 111 is supplied to the two inverter circuits 102 and 111 in parallel. However, the present invention is not limited to this. For example, DC power rectified by a rectifier circuit provided for each inverter circuit may be supplied to each inverter circuit for each inverter circuit.

  DESCRIPTION OF SYMBOLS 1 ... Power converter device, 102 ... 1st inverter circuit, 111 ... 2nd inverter circuit, 12 ... Coupling reactor, 13 ... Current detection circuit, 130-134 ... Current detection part, 14 ... Control part, 144 ... Current calculation Part

Claims (2)

Two or more inverter circuits that convert DC power into polyphase AC power, a current detection circuit that detects an output current output from the two or more inverter circuits, and a detection current that is detected from the current detection circuit A power converter comprising: a control unit that controls output currents of the two or more inverter circuits based on:
The current detection circuit includes a current detection unit that detects an output current of a remaining phase excluding one phase that does not detect the output current among phases output from the two or more inverter circuits.
The control unit is based on a combined current obtained by combining the detection currents detected by the current detection unit, so that the combined current of the output currents of all the phases becomes zero. A power conversion device comprising: a current calculation unit that determines an output current of the output by calculation. Two inverter circuits that convert DC power into three-phase AC power, a current detection circuit that detects an output current output from the two inverter circuits, and the 2 based on the detection current detected from the current detection circuit A power converter comprising a control unit for controlling the output current of two inverter circuits,
The current detection circuit includes a current detection unit that detects an output current of the remaining five phases excluding one phase that does not detect the output current among the six phases output from the two inverter circuits,
The control unit is detected by the current detection unit based on a combined current obtained by combining the five-phase detection currents detected by the current detection unit so that a combined current of all the six-phase output currents becomes zero. A power conversion device comprising: a current calculation unit that determines an output current of one phase that is not calculated by calculation.

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