To reduce burden of a filter capacitor removing noise, to prolong life of the filter capacitor, to miniaturize it, and to prevent influence of noise to a load.

An inverter 2 converts DC power from a DC power supply 1 into AC power, and it is supplied to the load 5 without transformer. The star-connected filter capacitors 4 are installed between the inverter 2 and the load 5. A neutral point of the filter capacitor 4 and an intermediate point of the DC power supply 1 are connected by a neutral wire 10. A first parallel LC resonance circuit 12 where a resonance frequency is a frequency of current distortion and is a tertiary harmonic of an output frequency of the inverter 2 is arranged in the neutral wire 10.

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