To increase regeneration efficiency when kinetic energy at the time of deceleration of an electric vehicle is regenerated as electrical energy, by converting kinetic energy at the time of deceleration of the electric vehicle into direct-current or alternating-current power, converting the direct-current or alternating-current power into pulse power, and charging a battery with the pulse power obtained by the conversion.

Conversion of kinetic energy at the time of deceleration of an electric vehicle into electrical energy is done by a generator. In the case of an EV(electric vehicle) and an HEV(hybrid electric vehicle), a motor for driving a vehicle has the same structure as a generator, supply of power to the motor is cut off at the time of deceleration, the motor is used as a generator, and power is generated by a braking force. Next, the power converted from kinetic energy is inverted into pulse-formed power by a pulse inverter. An inverter with switching elements, etc., is used as the pulse inverter. When a battery is charged with the pulse-formed power obtained by the inversion, a protection circuit is provided for overcharge prevention.