Electric power converting device and electric power converting method

摘要

In one embodiment, an electric power converting device includes a converter which converts a three-phase AC voltage output from a three-phase AC power source, into a DC voltage of each phase of a three-phase AC load, and an inverter which converts the DC voltage converted by the converter, into a single-phase AC voltage of each phase of the three-phase AC load. The converter includes for each phase of an electric power system a circuit which consists of a plurality of switching elements connected in series. The electric power converting device controls on/off of a switching element corresponding to one of phases of the electric power system in the converter such that a voltage which reduces fluctuation of a DC voltage applied between the converter and the inverter and corresponding to each phase of the three-phase AC load is output from the converter for each phase of the electric power system.

主权项

1. An electric power converting device comprising:
a converter which converts a three-phase AC voltage output from a three-phase AC power source, into a DC voltage of each phase of a three-phase AC load; an inverter which comprises a plurality of neutral-point-clamped (NPC) legs per phase and converts the DC voltage converted by the converter, into a single-phase AC voltage of each phase of the three-phase AC load; and a capacitor which is connected to a terminal between the converter and the inverter, wherein: the converter comprises for each phase of an electric power system a circuit which consists of a plurality of switching elements connected in series; and the electric power converting device further comprises a control unit which controls on/off of a switching element corresponding to one of phases of the electric power system in the converter such that a voltage which reduces fluctuation of a DC voltage applied between the converter and the inverter and corresponding to each phase of the three-phase AC load is output from the converter for each phase of the electric power system.