Patent ID: 8649196
Filing Date: 2014-02-11
Classification: H02M

Abstract:
1. A power converting apparatus comprising a first inverter which converts DC power fed from a first smoothing capacitor connected to a first DC power supply into AC power and a plurality of second inverters which are connected in series to an AC output line of said first inverter and convert DC power fed from respective second smoothing capacitors into AC power, wherein voltages of said second smoothing capacitors are lower than a voltage of said first smoothing capacitor, said plurality of second inverters output voltages approximately equal to each other by performing PWM control so that an output power balance during one cycle becomes approximately zero, and said power converting apparatus outputs a sum of an output voltage of said first inverter and the output voltages of said plurality of second inverters, said power converting apparatus further comprising: voltage command generating means for individually generating output voltage commands for said plurality of second inverters, wherein said voltage command generating means generates the output voltage commands upon individually making an adjustment so that the voltages of said individual second smoothing capacitors become equal to each other depending on whether said second smoothing capacitors are in charging or discharging mode while keeping a sum of the individual output voltage commands at a target sum voltage to be matched by a sum of the output voltages of said plurality of second inverters.