To provide a protection technique for a regenerated-energy accumulator that uses an electric double-layer capacitor for protecting the regenerated- energy accumulator, particularly for a regenerated-energy accumulating means.
The accumulator comprises: an inverter 1 that converts a DC to an AC; a motor load 2 that is driven by the inverter; a DC capacitor 3 that controls the instantaneous ripple of a DC input voltage of the inverter; a DC power source 5; the regenerated-energy accumulating means 6; a DC/DC converter 7 that connects the regenerated-energy accumulating means and the DC input of the inverter; and a conduction ratio control means 8 that controls the conduction ratio of the DC/DC converter. The DC input voltage of the inverter 1 is detected, and, when the detected voltage exceeds a prescribed level, the conduction ratio of the DC/DC converter is changed so as to raise a charge current to the regenerated-energy accumulating means, thus protecting the inverter, DC/DC converter and regenerated-energy accumulating means.
NAKAZAWA YOSUKE
YUKI KAZUAKI
