| 摘要 |
PURPOSE: To enlarge the change width of output voltage without reducing motor efficiency by controlling the output voltage of a DC-DC converter and switching circuit with a signal to control the revolution of a motor, and putting the coil used in the DC-DC converter in common to one for use of power supply to each control part. CONSTITUTION: A revolution control means (Rc) 15 outputs control signals of frequency and output voltage for controlling the revolution of a motor 14. A RAM controller 16 controls the output voltage of a DC-DC converter (DC) 11 with the control signal of RC15. A PWM control means 17 controls a switching circuit 12 with the control signal of RC 15. A primary coil 18 is used for as a reactance inserted on the positive side between output terminals of a full wave rectification circuit 1. A transformer 19 uses the primary coil 18. Therefore, the amplitude of the pseudo sine waves and the frequency of pseudo sine waves of the switching circuit 12 can be varied with DC 11, so the change with of the output voltage can be enlarged without reducing motor efficiency. |
