| 摘要 |
PURPOSE:To suppress a peak current flowing in the semiconductor switch of the inverter circuit by employing a thyristor for a part of a rectifying circuit becoming the input source of the inverter circuit and controlling the conducting angle of the thyristor at the starting time. CONSTITUTION:A current for driving a DC motor 9 is supplied through the semiconductor switch controlled by a switching control circuit 3, and a direct current obtained by rectifying the AC from the AC power source 12 is smoothed by elements 18, 10 and is supplied to the circuit of the semiconductor switch 1. A diode 11 and a thyristor 19 are used for the rectifier. The phase control circuit 17 controls the conducting angle of the thyristor 19. By controlling the conducting angle of the thyristor 9 at the time of starting the motor 9 the output voltage of the rectifying circuit is suppressed, thereby suppressing the peak current flowing through the semiconductor switch 1. |
