Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Tomonori Ouchiyama

Makoto Katayama

Katsumi Endo

Koji Hamaoka

Hidehisa Tanaka

Hidetoshi Nishihara

Shuichi Yakushi

Tatsuyuki Iizuka

Yuji Saiki

A compressor includes a motor driven by a controller and having a rotor and a stator, a compressing unit driven by the motor in a hermetic container in which refrigerant is filled. Driving the motor at a low rpm, the controller practices a feedback control which determines a timing of turning on/off switching elements based on a signal detecting a position of the rotor, and when the motor is driven at a high rpm, the controller practices an open-loop control which outputs a given frequency and drives the motor synchronizing with the given frequency. This structure achieves a compressor working with a fewer noises in PWM driving.

Electric compressor

A rectangular wave or a waveform similar to the rectangular wave is output with an conductive angle no less than 120&#xb0; but no more than 150&#xb0; during low-speed operation, but output a rectangular wave, a sine wave or a waveform similar to them with an conductive angle no less than 130&#xb0; but under 180&#xb0; by changing the frequency only while maintaining the PWM duty constant at high-speed operation, making it possible to realize high-efficiency and low-noise operation at low-speed operation, secure stable high speed, and prevent peak current of effective current because the current waveform also comes closer to sine wave.

Brushless DC motor driving method and apparatus for it

Growing community of inventors

Kusatsu, Japan

Tomonori Ouchiyama