Matsushita Electric Industrial Co., Ltd.

Shiro Maeda

Mitsuhisa Nakai

Toshiaki Yagi

Shigeru Muramatsu

Shuichi Yamamoto

Osamu Aiba

Sadao Kawahara

Manabu Sakai

Michio Yamamura

Yoshinori Kojima

Jiro Yuda

Tomohiro Sugimoto

Akihiro Kyogoku

Kazuhiro Harada

Yasuhisa Ninomiya

Power apparatus

Starting method for scroll-type compressor

A brushless motor operating apparatus includes a DC power source 1, a group 2 of semiconductor switching elements for passing/interrupting a current to an armature winding 4 of a brushless motor 3, a plurality of filter circuits 6 for waveform-processing induced voltages induced in the armature winding 4, a comparison circuit 7 for comparing outputs of the plurality of filter circuits 6 and a composite wave thereof, a control circuit 8 for making ON/OFF control of the semiconductor switching element group 2 in accordance with an output of the comparison circuit 7, the filter circuit 6 having a construction in which condensers 6c and 6e are connected behind and in series with a voltage divider circuit composed of a plurality of resistors 6a and 6b and an integrating circuit 6d is connected behind the condensers 6c and 6e, whereby the condensers 6c and 6e in the filter circuit 6 can be provided with ones having a low withstanding voltage, thereby making it possible to reduce the size and cost of the apparatus.

Brushless motor operating apparatus provided with a filter having a

By making different duty controls at the time of change in rotating speed and at the time of stable rotating speed, respectively, it is possible to realize the driving of a brushless motor 3 which enables smooth and rapid change of a rotating speed coping with a load.

Method and apparatus for driving a brushless motor including varying the

In a brushless motor, during a synchronized operation mode, n kinds of driving waveforms having the first to n-th patterns are sequentially outputted and the outputting of the n-th pattern is followed by cyclically outputting the patterns again in a sequence from the first pattern, thereby generating a rotating magnetic field in an armature winding. Upon transition from the synchronized operation mode to a rotor position detection operation mode, the commutation signal is changed over from the synchronizing signal to a signal based on the rotor position detector signal after the (n-1)th pattern has been outputted and at a timing when the n-th pattern is to be subsequently outputted. Thereby, upon transition from the synchronized operation mode to the rotor position detection operation mode, the commutation signals are linked in a proper sequence so that smooth mode transition becomes possible without the addition of any special ancillary circuit.

Brushless motor operating method and apparatus

In a brushless motor, the frequency of an output signal of a synchronizing signal generation unit, a duty ratio in a synchronized operation mode and a duty ratio in a rotator position detection operation mode are set such that a rotating speed in the rotator position detection operation mode becomes equal to or lower than a rotating speed in the synchronized operation mode, thereby enabling smooth change-over from the synchronized operation mode to the rotator position detection operation mode.

Brushless motor driving method and apparatus

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Kusatsu, Japan

Shiro Maeda