| 摘要 |
PURPOSE:To eliminate the fluctuation in DC voltage and to reduce the capacity of a DC smoothing capacitor by suppressing the fluctuation in the DC voltage of a main PWM converter which fluctuates due to the frequency which is twice the frequency of a single-phase AC power supply with an LC series resonance circuit and a DC active filter. CONSTITUTION:A compensation current IA flowing to a DC active filter DC-AF is detected by a current detector CTA and is input to a current control circuit ACRA. The current control circuit ACRA inverts and amplifiers the deviation (=I'A-IA) between a compensation current command value I'A, and the compensation current detection value IA and gives a voltage command value to a PWM control circuit PWMC3. A voltage-type PWM inverter VSI generates a voltage proportional to a voltage command value and controls the compensation current IA. The DC active filter DC-AF takes the compensation current IA=I'A =(Idc)-IFO and the LC series resonance circuit takes the IFO thus preventing the fluctuation component of a single-phase power from flowing to a main smoothing capacitor Cd and eliminating voltage fluctuation. |
