| 摘要 |
PROBLEM TO BE SOLVED: To suppress the power consumption of a motor while the rotational accuracy of the motor is improved by applying series control to the rotating speed of the motor by means of a group of semiconductor elements which are assembled in a bridge that generates a rotating magnetic field and supplying a high voltage as the input voltage of the semiconductor element group when the motor is started to rotate and a low voltage when the motor rotates in a steady state. SOLUTION: When a motor M1 is rotated at a fixed speed, the voltage of a power source Vcc is lowered within a range in which the rotating speed of the motor M1 can be controlled or the inductances of star-connected inductors L2-L4 in the motor M1 are increased so as to suppress the losses which are caused when transistors Q2, Q4, and Q6 are operated in an unsaturated area. When the motor M1 rises to a constantspeed rotation from a stopping state, a transistor Q19 is switched by driving a PWM circuit 4 with a signal from a controller. When the transistor Q19 is switched, a boosted voltage is impressed upon transistors Q1-Q6 from a boosting regulator composed of an inductor L1, the transistor Q19, and a diode D1. Consequently, a very large current is supplied to the motor M1 and the rotating speed of the motor Ml can be increased quickly. |
