A power converter stabilizes a voltage by controlling leading of an AC current and performs maximum charging within contracted power reception amount when connected to a weak power system. The power converter comprises Magnetic Energy Recovery Switch comprising a bridge circuit including at least two reverse conductive type semiconductor switches and a magnetic energy accumulating capacitor with a small capacity connected between DC terminals of the bridge circuit. The power converter uses the Magnetic Energy Recovery Switch to perform power conversion from AC to DC or vise versa. Plurality of secondary battery charging devices each comprising the power converter have a DC part connected to a common DC bus bar, so that power is accommodated among the secondary battery charging devices.