Power converter and power conditioner

An aspect of the invention provides a power converter that enhances conversion efficiency from a DC power to an AC power. A first chopper circuit (5) chops a DC voltage from a photovoltaic panel (1) at a system frequency to produce a first square-wave voltage string whose voltage level changes onto a positive side, a second chopper circuit (6) chops the first square-wave voltage string at a frequency double the system frequency to produce a second square-wave voltage string whose voltage level changes onto a negative side and adds the first square-wave voltage string and the second square-wave voltage string to produce a third square-wave voltage string that alternately changes in a sine-wave manner on positive and negative sides, a third chopper circuit (7) performs charge and discharge by chopping the third square-wave voltage string at a third frequency fixed by timing according to a positive or a negative of a difference between the third square-wave voltage string and a sine-wave voltage, and PWM control is performed to outputs of the charge and discharge such that the difference is corrected, thereby producing a sine-wave voltage that continuously changes on the positive and negative sides. Further, a spike noise of an output voltage is suppressed.