To make it exhibit rapidity and to achieve higher efficiency of a brushless DC motor, such as the ripples of motor action not occurring, when switching two waveform output means.
The ripples of motor action can be suppressed, by switching the first waveform generator 6, which outputs waveform 150° or under in energization angle, and a second waveform generator 7, which outputs waveform less than 180°in energization angle, while changing the specified frequency and the angle of energization, keeping the angle of energization, which can contribute to the stability of a system. Furthermore, High speed properties and high torque properties can be realized by enlarging the angle of energization as occasion demands during selection of the second waveform generator 7, and it can exhibit its effect on the cooling speed increase of a refrigerator and the control of slow cooling at midsummer.
HAMAOKA KOJI
TANAKA HIDENAO
Tomoyasu Sakaguchi
Hiroki Naito