| 摘要 |
PROBLEM TO BE SOLVED: To enhance power factor of a PAM controller by controlling the output of a motor only through PWM control of a single transistor thereby eliminating the need for controlling the output through a circuit for switching a coil depending on the phase position of a rotor. SOLUTION: A power transfer control circuit 17 performs PWM control of a transistor 14 with a pulse width corresponding to the output level of a motor. When the transistor 14 is turned on/off at a high rate, an output capacitor 16 is charged during off interval with electromagnetic energy stored during on interval by a transformer 13. A DC voltage corresponding to the output level is generated in a capacitor 16 and the motor output is controlled. Furthermore, it is combined with boost control of chopper transformer by decreasing the capacity of a capacitor 12. Since current is consumed even in a phase section where the voltage of full-wave rectified waveform is low and follows up the AC voltage, power factor of a PAM controller is enhanced. |
