Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Yukimori Kishida

Hiroyuki Sasao

Kenichi Koyama

Hiroyuki Akita

Toshie Takeuchi

Mitsuru Tsukima

Toshimasa Maruyama

Toyomi Ooshige

Hiroshi Yamamoto

Akihiko Iwata

Toshiyuki Yoshizawa

Kazuhiko Kagawa

Akira Imanaka

Shinichi Ogusa

Chie Takahashi

Yuichi Yamaji

Kazuhiko Nishimiya

Eiji Moritoh

Toshiyuki Fujii

Osamu Mori

Tetsuaki Nagano

Masaya Harakawa

Masakazu Fukada

Junichiro Ishikawa

Yasuhiro Sekimoto

Takafumi Nishioka

Yoichi Ueno

Tokio Nakashima

Masanori Yasue

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 converter controllable in regenerative running mode, which is a power converting apparatus capable of suppressing harmonics without increasing the size of a reactor, and reducing power loss and electromagnetic noise. A power converter is configured by directly connecting AC sides of single-phase sub-converters having a DC voltage lower than a DC voltage of a 3-phase main converter to AC input lines of individual phases thereof in series. The main converter is driven by one gate pulse per half recurring cycle and a voltage produced by each sub-converter at AC terminals thereof is controlled to match a difference between an AC power supply voltage and a voltage produced by the main converter at AC terminals thereof, whereby phase voltages of the power converter are generated as the sums of phase voltages of the individual converters.

Power converting apparatus with main converter and sub-converter

A power conversion device including sub-inverters, each connected in series with respective phase of a three-phase main inverter including a smoothing capacitor, which is fed from a power supply via a converter, as a DC input thereof, and feeds power to a load using the sum of outputs of the inverters. A manipulative quantity is determined so that the DC voltage at each of smoothing capacitors which is an input of each of the sub-inverters will follow a command value. The manipulative quantity is added to an output voltage command for the three-phase main inverter, and is subtracted from an output voltage command for the sub-inverters. Thus, power is shifted from the three-phase main inverter to the smoothing capacitors of the sub-inverters.

Power conversion device

A switching apparatus for multiphase electric power includes switching units corresponding to different phases. Each switching unit includes an operating mechanism having a movable coil disposed between two fixed coils, and a switch portion having a movable contact operatively connected to the movable coil. A separate power supply may be provided for each switching unit to permit individual control of the different phases.

Switching apparatus

A switching device includes a pair of fixed coils and a pair of movable coils, with one pair being disposed between the other pair. Two of the coils may be connected back to back on opposite sides of a support plate to increase the stiffness of the coils and reduce damage due to impact between the fixed and movable coils. The coils include two sets of coils, each set including one of the fixed coils and one of the movable coils. The coil sets can be driven simultaneously or at different times to effect contact opening and closing.

A switching device includes a movable coil which is reinforced by a stiffener to increase the resistance of the movable coil to bending moments. The stiffener may include a nonmagnetic case which surrounds the movable coil. Alternatively or in addition, it may include a resin or other material encapsulating the movable coil.

Switching device

An electromagnetic repulsion drive switching device in which a contact-closing coil and a contact-opening coil are arranged to confront a conductive repulsive member, and in which a drive current is fed to a selected one of the individual coils from a capacitor charged to a predetermined charge voltage by a charging power source. A stationary contact and a movable contact are brought into and out of contact by a repulsion electromagnetic force generated between the coils and the repulsion member. A voltage control controls the output voltage of the charging power source so that the peak value of the drive current may fall within a range with respect to a temperature change of the capacitor. As a result, even if the working temperature of the capacitor changes, the drive current of the contact-closing coil and the contact-opening coil falls within a desired range.

Electromagnetic repulsion driven switch

A switching assembly includes a switch portion having a fixed electrode and a movable electrode which are separable, a movable portion secured between a movable shaft connected to the movable electrode and a movable coil by a magnetic body, and a fixed portion having a magnetic body disposed radially inside a fixed coil disposed opposite the movable portion, thereby enabling intensification and swift establishment of magnetic fields generated between the coils.

Switching assembly

In a switchgear, by using a spring with a varying spring constant from closing to electrode opening as a loading spring, spring load in the opened electrode state is made smaller than a spring load in the closed electrode state to decrease the energy required from electrode closing up to electrode opening. Moreover, by using a spring in which a load in the opposite direction to a load in the closed electrode state works in the opened electrode state, the opened electrode state can be held securely.

Switchgear

A switching apparatus includes a switch, a movable coil, stationary coil members, and a direction-of-conduction setter comprising diodes. The switch has a stationary electrode. The movable coil is fixedly mounted on a movable shaft coupled to the movable electrode. The stationary coil members are opposed to the movable coil. The power supply supplies an excitation current to the coils. The direction-of-conduction setter sets the direction of conduction, in which the excitation current flows from the power supply into the coils, so that the coils will electromagnetically react on each other. This arrangement provides highly efficient electromagnetic driving. Moreover, an opening power supply or closing power supply is required to have only a small capacity.

A fast changeover from one power system to another in the event of an irregularity in the power source system substantially reduces operating costs by minimizing a power loss in switches during conduction, dispenses with a cooling device for cooling a thyristor switch, and implements the thyristor switch in a compact and low-cost design. The power supply system for a load includes one switching apparatus for connecting a load to one power source system, and another switching apparatus for connecting the load to another power source system. Each of the switching apparatus includes a pair of thyristors connected in anti-parallel and a mechanical switch connected in parallel with the thyristor pair. The thyristor pairs and the mechanical switches are controlled so that the mechanical switches conduct a load current when the load is supplied with power from the one power source system in a steady power supply state. The thyristor switches conduct the load current during a power source changeover time within which the load is disconnected from one power source system and connected to the other power source system, and do not conduct the load current during the steady power supply state.

Electric power supply system for load

A switching device has a control section to transfer a gate control signal which switches plural thyristors from an ON state to an OFF state after a parallel switch is open and an opening degree of the parallel switch is met where no arc discharge is generated at a contact point in the parallel switch.

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Tokyo, Japan

Yukimori Kishida