Patent ID: 8659924

Claim:
A power conversion apparatus, comprising: a rectification circuit for rectifying an input from a single-phase AC input power supply; an inverter circuit including at least one single-phase inverter having a plurality of semiconductor switch devices and a DC voltage supply, an AC side of the at least one single-phase inverter being connected in series with an output of the rectification circuit, which inverter circuit superimposes a sum of outputs of the at least one single-phase inverter onto the output of the rectification circuit; a smoothing capacitor for smoothing an output of the inverter circuit, the smoothing capacitor being connected via a rectification diode to the inverter circuit at a subsequent stage of the inverter circuit; and a short-circuiting switch for bypassing the smoothing capacitor, one end of the short-circuiting switch being connected to the inverter circuit and the other end being connected to one end of the smoothing capacitor, wherein: the inverter circuit is subjected to output control by PWM control using a current instruction such that a voltage of the smoothing capacitor follows a first target voltage and an input power factor from the single-phase AC input power supply is improved, the short-circuiting switch is subjected to ON/OFF control such that a voltage of the DC voltage supply of the inverter circuit follows a second target voltage, and each of ON periods of the short-circuiting switch includes a zero cross phase of an input voltage from the single-phase AC input power supply.