Toshiba Mitsubishi-electric Industrial Systems Corporation

Mitsubishi Electric Corporation

Yasuhiro Shinomiya

Taichiro Tsuchiya

Takushi Jimichi

Kimiyuki Koyanagi

Sadao Funahashi

Ryota Okuyama

A power converter is electrically connected with an AC power supply via a switch, and is configured with a plurality of unit converters () connected in series. A drive circuit () drives a plurality of switching elements (to) of a main circuit (). An interface circuit () outputs a detection value of a voltage sensor () to a control device (). If a bypass switch () is turned off when the power converter is activated, each of the plurality of unit converters () charges a capacitor () using power supplied from the AC power supply. When the power converter is activated, a power supply () supplies a power supply voltage to the voltage sensor () and the interface circuit (), prior to the drive circuit (). The control device () turns off the switch when the detection value of the voltage sensor () of at least one of the plurality of unit converters () is more than or equal to a predetermined value.

Power conversion device

A power conversion device in which a plurality of converter cells are connected in series with one another. The converter cells each include two or more semiconductor devices, an energy storage element and a bypass element including a constituent element for setting the bypass element to be close-circuited by detecting abnormality of a converter cell, and including a constituent element for controlling, among the semiconductor devices, a semiconductor device connected in parallel with the bypass element to set in a turn-on state, at the same time when the bypass element is set close-circuited or in advance of its close circuit.

A power conversion device including: an energy storage unit which receives and stores voltage of a self-power-feeding device; and a bypass unit drive device which, when voltage of the self-power-feeding device becomes smaller than a predetermined lower limit value, causes a bypass unit to perform short-circuiting operation by power stored in the energy storage unit. Thus, by appropriately setting the above voltage lower limit value as a threshold value for the short-circuiting operation, it becomes possible to swiftly and reliably perform short-circuiting protection operation even if a cell converter has failed, thus it is possible to always safely continue the operation of the power conversion device.

Growing community of inventors

Chuo-ku, Japan

Yasuhiro Shinomiya