Mitsubishi Electric Corporation

Mitsubishi Denki Kabushiki Kaisha

Junichiro Ishikawa

Hiroyuki Takagi

Shigeki Yamakawa

Kazuhiro Otsu

Akihiko Iwata

Toshiyuki Fujii

Osamu Mori

Yasushi Nakayama

Hiroshi Ando

Yoshiko Tamada

Yukimori Kishida

Akihiro Chida

Seiji Okuda

Tatsushi Takahashi

Yoshitaka Naka

Kunio Katou

Tomohiko Yao

Masanori Yasue

Naohiko Mitomi

A short-circuit protection circuit for a self-arc-extinguishing type semiconductor element includes a first protection circuit and a second protection circuit. The first protection circuit is configured to reduce a voltage between a control electrode and a first main electrode of the self-arc-extinguishing type semiconductor element when detecting overcurrent flowing between the first main electrode and a second main electrode. The second protection circuit is configured to: detect current flowing in an interconnection adapted to supply the drive voltage; determine, based on the detected current, whether the first protection circuit is in an operating state; and change the drive voltage to turn off the self-arc-extinguishing type semiconductor element when the first protection circuit is in the operating state.

Short-circuit protection circuit for self-arc-extinguishing type semiconductor element

A gate driving circuit for an insulated gate-type power semiconductor element includes an Nch MOSFET which turns on the insulated gate-type power semiconductor element, a Pch MOSFET which turns off the insulated gate-type power semiconductor element, a control circuit which turns on the Nch MOSFET by applying a positive voltage to the gate electrode of the Nch MOSFET, and which turns on the Pch MOSFET by applying a negative voltage to the gate electrode of the Pch MOSFET, and a power supply which applies a negative voltage to the drain electrode of the Pch MOSFET and to a negative-side electrode of the control circuit, which applies a positive voltage to the drain electrode of the Nch MOSFET, and which applies to a positive-side electrode of the control circuit a positive voltage whose absolute value is larger than absolute value of the positive voltage applied to the drain electrode of the Nch MOSFET.

Gate driving circuit for insulated gate-type power semiconductor element

A composite semiconductor switching device includes: a first semiconductor element that incurs switching losses when performing switching operation of turning on and off; a second semiconductor element that is parallelly connected to the first semiconductor element and incurs switching losses larger than the first semiconductor element when performing switching operations of turning on and off; and a controller that operates in order of giving a first on-command signal to the first semiconductor element, giving a second on-command signal to the second semiconductor element, deactivating the first on-command signal, giving a third on-command signal to the first semiconductor element, and deactivating the second on-command signal.

Composite semiconductor switching device

A power converting apparatus is configured with single-phase sub-converters () connected to AC input lines of individual phases of a three-phase main converter () in series therewith. In a control device () for performing output control of the power converting apparatus, a current command value calculating circuit () which adjusts a DC voltage command given to the main converter () so that DC voltages of the sub-converters () follow a command and generates AC current commands so that a DC voltage of the main converter () follows the DC voltage command is configured with a CPU, and AC currents are controlled by switching output voltage levels of the sub-converters () at an AC side thereof so that deviations of instantaneous AC current values from the AC current commands become smaller.

AC-DC power converting apparatus having sub-converters connected in series between main converter and AC power supply

A power supplying system for an elevator includes: a first electric storage apparatus for storing thereinto electric power derived from a commercial power supply; a charging apparatus for charging the electric power derived from the commercial power supply to the first electric storage apparatus and for controlling a current when the electric power is charged into the first electric storage apparatus; a second electric storage apparatus for storing thereinto electric power used to operate an appliance of an elevator; and a power supplying apparatus for supplying the electric power derived from the first electric storage apparatus to the second electric storage apparatus.

Elevator power system having plural storage apparatuses

In a maintenance driving control apparatus of an elevator, switches and other components operated at the time of maintenance are separated from a control panel and combined in a driving operation panel. A maintenance operation panel having this driving operation panel and at least one of a brake release device for remote operation, a meter for indicating a voltage of a speed generator, and car position confirmation unit utilizing movement of a rope or some other member is provided in the vicinity of an elevator hall. The maintenance driving control apparatus enables maintenance operations without directly operating the control panel or a hoisting machine.

Elevator maintenance/operation apparatus

A controller for an elevator. The elevator includes a landing passageway where a car stops and passengers board or alight and a hoistway through which the car is raised or lowered. A control panel for controlling the raising, lowering, and stopping of the car is disposed in the hoistway at a position where the control panel does not interfere with the raising or lowering of the car, and a mechanism for drawing out the control panel to the landing passageway is provided. Accordingly, space in the hoistway is effectively used, and the landing passageway which passengers do not use during maintenance can be readily utilized for a maintenance operation.

Moveable control panel for elevators

Growing community of inventors

Tokyo, Japan

Junichiro Ishikawa