A power converter enhances conversion efficiency from DC power to
AC power. A first
chopper circuit chops
DC voltage from a photovoltaic panel at a
system frequency producing a first square-wave whose
voltage level changes positively. A second
chopper circuit chops the first square-wave at a frequency double the
system frequency producing a second square-wave whose
voltage level changes negatively and adds the first square-wave and the second square-wave to produce a third square-wave that changes positively and negatively in a sine-wave manner. A third
chopper circuit charges and discharges by chopping the third square-wave at a third frequency fixed by timing according to a difference between the third square-wave and a sine-wave
voltage. PWM control is performed on the
charge and discharge outputs such that the difference is corrected, producing a sine-wave voltage that continuously changes positively and negatively. A spike
noise of an output voltage is suppressed.