Mitsubishi Electric Corporation

Kazuya Nakamura

Manabu Ohashi

Kei Terada

Kazutaka Takahashi

Shigeo Jimbo

A circuit disconnection element that can open or short-circuit between a power storage element and a step-up/step-down bidirectional chopper circuit is provided in a power storage system, thereby preventing a self-discharge state in a process of charging. Furthermore, at the time of occurrence of an abnormality, the power storage element is detached from other devices including the step-up/step-down bidirectional chopper circuit. Accordingly, an energy loss of the power storage element at the time of power regeneration can be reduced to improve the energy use efficiency. Further, breakage influences such that the power storage element causes breakage in other devices at the time of occurrence of the abnormality can be prevented, thereby enabling to obtain an AC motor drive device having mounted therein a highly safe power storage system.

AC motor drive device

To provide an electric power conversion device that converts direct current power supplied from a direct-current power supply into alternating current power, the electric power conversion device includes six switching elements constituted by a voltage-driven transistor that uses a wide bandgap semiconductor and a diode, and a drive circuit that controls a voltage for driving the transistor at a time of turning off the switching elements based on a predetermined voltage profile specifying that the transistor is operated in a non-linear region.

Electric power conversion device and surge voltage suppressing method

A circuit switching element is provided that switches a step-up/step-down bidirectional chopper circuit, arranged between a DC bus and a power storage element, to a first chopper circuit or to a second chopper circuit, whose step-up and step-down characteristics are in a complementary relation. The first and second chopper circuits are used together at a time of charge and discharge. Accordingly, an AC motor drive device having mounted therein a power storage system is obtained, in which the power storage system can perform charge and discharge to and from the power storage element, regardless of a bus voltage and can increase energy use efficiency.

Growing community of inventors

Chiyoda-ku, Japan

Kazuya Nakamura