Kabushiki Kaisha Toshiba

Kohsaku Ichikawa

Akio Hirata

Suzuo Saito

Kazuto Kawakami

Tadao Mose

Yukinori Tsuruta

Teruo Nakagawa

Tsugunori Kuga

Yuji Hashiya

The present invention is composed of: positive and negative control power sources P and N, first and second semiconductor device groups A and B in which a plurality of semiconductor devices,and,and also,and,are series-connected to these positive and negative control power sources P and N, switching signal source,that supplies ON/OFF control signals to semiconductor devices,and,and also,and,of these first and second semiconductor device groups A and B, and delay circuits,and,that delay for a specified time the ON/OFF control signals supplied to any one of semiconductor devices,and,and also,and,of first or second semiconductor device groups A and B from this switching signal source

Gate circuit for insulated gate semiconductor device

A fault detector apparatus for a power converter in which a plurality of GTOs, functioning at a predetermined potential, are used. The apparatus includes a first fault-detecting circuit, coupled to the gate-cathode path of one of the GTOs, for generating a first fault signal when this GTO malfunctions, a second fault-detecting circuit, coupled to the gate-cathode path of another one of the GTOs, for generating a second fault signal when this GTO malfunctions, a photocoupler for transmitting a DC-isolated optical signal corresponding to the first fault signal, and one optical fiber system for transmitting a DC-isolated output signal, corresponding to the logical sum of the optical signal transmitted by the photocoupler and the second fault signal, to external circuits set at a potential different from the potential at which the GTOs are arranged. The fault-detecting circuits are provided in the same number as the GTOs. The fault-detecting circuits are coupled by the optical signals.

Fault detector apparatus having serial fault-detection signal path

A turbine helper drive apparatus has an induction motor coupled to a turbine, and a power converter for power-controlling the motor. Part of the load of the turbine is shared by the motor in accordance with preset power for power control, so that auxiliary drive to compensate for the insufficient capacity of the turbine is performed and cheaper, late-night electric power is effectively utilized.

Turbine helper drive apparatus

Growing community of inventors

Tokyo, Japan

Kohsaku Ichikawa