SYSTEM LINKAGE POWER CONVERTING APPARATUS

摘要

A system linkage power converting apparatus that can provide a system linkage in which the reverse power flow occurs, in a commercial power system having a grounded power line for one of its two phases, with a high power conversion efficiency achieved, with any leakage current inhibited from flowing even when a DC electric generator set has a large earth capacity, with the current and voltage of an outputted AC power stabilized and with the balance between the positive and the negative kept. In this apparatus, a grounded power line (G) of the commercial power system is connected to a terminal (Y) of a series connection of two capacitors (C1,C2) that are series connected between the positive polarity end and the negative polarity end such that they equally share a DC voltage outputted by a DC power supply (E) that is the foregoing DC electric generator set. A CT (16) monitors an output current of an inverter part that uses four switching elements (S1-S4) and two diodes (D1,D2) to provide three levels of conversion of the voltage across the series circuit comprising the two capacitors (C1,C2). An operation control circuit (14) controls the generation of a PWM signal to be applied to the four switching elements (S1-S4) in such a manner that the difference between a current value determined by the CT (16) and a target current value becomes small.