Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Kazuyuki Mitsushima

Kenshi Kawagishi

Hidekazu Totsuka

Keiichi Yamamoto

Shinsaku Kusube

Haruhiko Ishida

Akihiko Imagi

Yoshio Yoshikuwa

Yasunori Shida

Tatsunao Hayashida

Keisuke Ishikura

Yukihiko Iwata

Yu Hasegawa

Norikazu Ishikawa

Takuo Akiyama

A harmonic current compensating device according to an embodiment of the present disclosure is a harmonic current compensating device including a power converter including at least a pair of arms each including a switching element, the harmonic current compensating device being configured to drive the switching element and supply compensating current to load current flowing between a system power source and a harmonic generating load, in which the switching element includes a unipolar device using a wide bandgap semiconductor.

High-frequency current compensator and air-conditioning system

The improved motor drive unit includes a zero-crossing voltage detector circuit composed of components (7) to (12) for detecting whether the voltage from an AC power supply (1) is zero-crossing and a switching circuit for performing on-off control by means of a thyristor 27 so as to switch between energization and de-energization of the AC power supply to a motor (2) and controls the speed of the motor by changing the ratio between the times of energization and de-energization of the AC power supply to the motor. The start of energization coincides with the zero-crossing of the AC power supply voltage whereas the timing of end of energization coincides with the zero-crossing of an energization current by means of the thyristor and wherein the energization time is fixed at a value either equal to or twice the power supply period whereas the de-energization time is varied in units that are integral multiples of one half the power supply period. If desired, a plurality of patterns for percent energization may be combined to attain a desired percent energization. Alternatively, a plurality of patterns that are equal in the ratio between the energization and de-energization times are used in combination. Only the main winding in the motor is preferably controlled for optimal energization.

Motor unit, motor drive unit, fan unit and method of controlling the

A control apparatus for a multi-air-conditioner having an external unit and a plurality of internal units includes a DC electric power supply. An external transmitting/receiving circuit is provided with the external unit and is connected with the DC electric power supply, and a plurality of internal transmitting/receiving circuits are provided with the plurality of internal units and are connected serially with the external transmitting/receiving circuit via a signal line. A DC voltage is supplied for transmitting data from the external unit to the internal unit, which reduces a leakage distance of the circuit. A timing for transmitting data can be set freely, a transmitting speed of data can be improved using a high-speed photo-coupler, and thus an operation speed of the internal unit can be improved in the multi-air-conditioner having the plurality of internal units.

Control apparatus for multi-air-conditioner

Growing community of inventors

Tokyo, Japan

Kazuyuki Mitsushima