Patent ID: 8472215

Claim:
A grid-tie inverter comprising: a single-phase or three-phase inverter that performs pulse width modulation for a DC voltage supplied from a DC power supply; a first capacitor circuit connected to an input side of the inverter so as to form a neutral point; a second capacitor circuit connected to an output side of the inverter so as to form a neutral point; a common mode current bypass channel formed by connecting the neutral point of the first capacitor circuit and the neutral point of the second capacitor circuit to each other; a grounded capacitor provided between the bypass channel and a ground; a first common mode choke coil unit including a common mode choke coil at least one of between the first capacitor circuit and the inverter and between the inverter and the second capacitor circuit, the first common mode choke coil unit that suppresses a common mode current occurring in the inverter; an output filter converting a pulse width-modulated voltage waveform outputted from the inverter into a sine single-phase or three-phase AC voltage, the output filter positioned between the inverter and the second capacitor circuit; and a grid transformer connected to an output side of the second capacitor circuit, a neutral point of the grid transformer connected to the ground through a neutral ground line, wherein at a switching frequency of the inverter, an impedance of the bypass channel is smaller than an impedance of a leakage current channel formed in which a leakage current flows through such a route that goes from the neutral point of the grid transformer to a stray capacitance of the DC power supply through the ground.