| 摘要 |
PROBLEM TO BE SOLVED: To accelerate or decelerate a centrifugal machine in a fixed time independently of the change in supply voltage by controlling a control means so that the charging voltage of a smoothing capacitor is fixed and by adjusting the amplification factor of the reference voltage comparison circuit of a power- factor improvement control circuit or adjusting the voltage of the supply voltage feedback signal of a supply voltage sensor. SOLUTION: A power-factor improvement control circuit 12 controls a bidirectional power converter 1 for power supply in order to suppress the higher harmonic component of a supply current and improve the supply power factor while maintaining the charge voltage of a smoothing capacitor 4 constant. The signal output of the power-factor improvement control circuit 12 drives a photocoupler 21 and turns its switching elements 1u, 1v, 1x, and 1y on and off. A control means 7 adjusts the amplification factor of the reference voltage comparison circuit of the power-factor improvement control circuit 12 or adjusts the voltage of the supply voltage feedback signal of a supply voltage sensor 9 in order to control the feedback value of the voltage sensor of the smoothing capacitor and has a function of changing the resistance value of a potentiometer, etc., or a function of voltage dividing. |
