Hitachi, Ltd.

Hitachi Cable, Inc.

Hitchi, Ltd.

Syuuji Saitoo

Akira Horie

Mutsuhiro Mori

Ryuichi Saito

Kiyoshi Nakata

Shin Kimura

Yoshihiko Koike

Shigeki Sekine

Eiichi Toyota

Heikichi Kuwahara

Yoshio Tsutsui

Takayuki Matsui

Kazumasa Fujioka

Takeshi Ando

Nobuo Suzuki

Koichi Isaka

Toshio Takasaki

An inverter device includes plural modules, each module being formed by a series circuit having a parallel circuit of a switching device and a first diode, and a parallel circuit of a second switching device and a second diode, allowing a reduced size, high reliability, high frequency switching and low noise. Each of the semiconductor modules includes a plurality of switching device chips and at least one diode chip formed on a metal substrate. Electrode plates are provided in locations of the module adjacent to the switching device chips and the diode chips to facilitate connection of the electrodes of the respective chips to one another and to the outside of the module.

Semiconductor module including switching device chips and diode chips

A cooling apparatus for electronic device comprises an electronic element unit which comprises a base member, a thermal conductive electric insulating layer soldered to the base member and a plurality of electronic elements soldered to the thermal conductive electric insulating layer at least one cooling unit which is detachably kept in pressure contact with the base member of the electronic element unit and comprises a cooling block, at least one heat pipe having a refrigerant sealingly contained therein and inserted in the cooling block at one end thereof and a plurality of radiation fins provided at the other end of the at least one heat pipe; and a device which serves to detachably keep the electronic element unit and the cooling unit in pressure contact with each other. The other end of the heat pipe extends obliquely with a predetermined angle (.alpha.) with respect to the inserted portion thereof.

Cooling apparatus for electronic elements

An inverter device includes plural modules, each module being formed by a series circuit having a parallel circuit of a first switching device and a first diode, and a parallel circuit of a second switching device and a second diode, allowing a reduced size, high reliability, high frequency switching and low noise.

Semiconductor module for a power conversion device

An inverter device includes plural modules, each module being formed by a series circuit having a parallel circuit of a first switching device and a first diode, and a parallel circuit of a second switching device and a second diode, allowing a reduced size, high reliability, high frequency switching and low noise. Each module forms one arm portion of the inverter. Lifetimes of the diodes and the switching devices are set in a manner to equalize losses in the inverter. Preferably, insulated gate bipolar transistors (IGBTs) formed by diffusion are used as the switching devices since the lifetimes of these devices can easily be adjusted to optimize design of the inverter.

Power conversion device and semiconductor module suitable for use in the

A cooling apparatus having a plurality of heat pipes is improved to reduce the condensation capacity of selected heat pipes when ambient air temperature is low, so as to facilitate start-up of the cooling apparatus from a state in which the working fluid in the heat pipes has been frozen. The cooling apparatus has a block of a high heat conductivity in which one end of each heat pipe serving as an evaporation section of the heat pipe is embedded. Heat radiation fins are attached to portions of the heat pipes exposed from the block, so that the exposed portions of the heat pipes serve as condensation sections of the respective heat pipes. There are two types of heat radiation fins: a first type of fins which are attached to all the heat pipes and a second type of fins which are attached only to selected heat pipes.

Heat-pipe type cooling apparatus

A power converter including a snubber circuit which is smaller and regenerates more energy than a conventional snubber circuit. A plurality of self-quenching semiconductor switching elements are connected in series across a power supply. A capacitive element is connected to the switching elements, and is charged to more than the voltage of the power supply by a snubber action due to operation of any of the switching elements. The charge stored in the capacitive element is then regenerated to the power supply. The capacitance of the capacitive element can be almost as small as a minimum required capacitance, and can be as small as one-tenth of the capacitance required in a conventional snubber circuit, thereby providing a power converter which is smaller and has a smaller snubber loss than a conventional power converter.

Power converter

Neutral-point clamped inverter device using semiconductor modules

Growing community of inventors

Katsuta, Japan

Syuuji Saitoo