THREE-PHASE POWER CONVERTING APPARATUS

摘要

A three-phase inverter circuit (4) of which DC portion is smoothing capacitors (3) connected between output terminals of a solar battery (1) and single-phase inverters (5a-5c) connected in series with AC output lines of the three-phase inverter circuit (4) together constitute an inverter section, and this inverter section is connected to a three-phase power system (2). The three-phase inverter circuit (4) outputs a reverse-polarity voltage pulse (10ua) during a period within each of basic voltage pulses of which pulsewidth corresponds to a half cycle every half cycle of a system voltage. A power burden born by the individual single-phase inverters (5a-5c) in each half cycle is made approximately zero and the individual single-phase inverters (5a-5c) make a correction for subtracting a common voltage (Vo) from target output voltages of individual phases during the period when the reverse-polarity voltage pulse (10ua) is generated.