| 摘要 |
PROBLEM TO BE SOLVED: To provide a power converter which converts power from a direct-current power supply into an alternating current and interfaces it with a system, without the use of an insulating transformer, and reduces the occurrence of leakage current. SOLUTION: When a three-phase, three-wire system with one wire grounded is connected, the intermediate point between two series capacitors 19, 20 is connected with the wire at ground potential of the three-phase, three-wire system to control the current of three sets of half-bridge inverters 4-6. Through the wire used to connect the intermediate point between the two series capacitors 19, 20 with the wire at ground potential of the three-phase, three-wire system, a current equivalent to the difference between the current obtained by summing the currents passed through the other two phases and reversing the polarity of the sum, and the output current of the half-bridge inverter 5 connected with the phase, is flowed. However, the intermediate point between the capacitors 19, 20 is fixed at the ground potential of the system. When the capacitance of the capacitors 19, 20 is sufficiently large therefore, the voltage fluctuation in the capacitors 19, 20 is reduced and the potential of a direct current part is fixed at the ground potential. Thus leakage current due to oscillation of the direct-current parts can be reduced. |
