| 摘要 |
PURPOSE:To realize an arbitrary speed control with high power factor and high efficiency and to sustain operation through modification of wire connection even in case of fault by providing a smoothing capacitor to be charged with DC output from a PWM converter, a PWM inverter, a diode converter, connection switching terminals. CONSTITUTION:A connection switching terminal 22 normally connect a smoothing capacitor 15 with a PWM converter 12 and a PWM inverter 16 where a circuit breaker 13 is closed and a circuit breaker 21 is opened. At this time, the PWM converter 12 converts an AC power, fed through the circuit breaker 13 and an AC reactor 14, into DC power for charging the smoothing capacitor 15. The PWM inverter 16 inverts the DC power charged in the smoothing capacitor 15 into VVVF AC power which is then fed to a squirrel- cage induction motor 17. Upon fault of the PWM converter 12, the terminal 22 is switched to connect the smoothing capacitor 15 with the PWM converter 16 and a diode converter 20 thus interrupting the circuit breaker 13 and closing the circuit breaker 21. |
