| 摘要 |
PROBLEM TO BE SOLVED: To lower a power supply voltage, lower a switching frequency and reduce ripples. SOLUTION: A power inverter is composed of a plurality of arms consisting of switching devices 21-26. Load devices 51-53 are connected to the multiphase output ends of the power inverter. Series connection unit composed of two capacitors 61 and 62 is connected to the DC input ends of the power inverter. Bidirectional switches 71-73 are connected between the connection point of the two capacitors 61 and 62 and the multiphase AC output ends respectively. Further, if the control deviation of the control of an AC output current exceeds a predetermined value, the positive pole side connection switching devices of the DC input ends are turned on and, if the deviation is smaller than the predetermined value, the negative pole side connection switching devices of the DC input ends are turned on and, if the deviation is within the predetermined range, the bidirectional switches 71-73 are turned on. |
