PARALLEL-TYPE ACTIVE FILTER

摘要

PROBLEM TO BE SOLVED: To provide a load output voltage detection-method parallel-type active filter which can compensate for higher harmonic waves of a capacitive non- linear load with high performance. SOLUTION: The higher harmonic voltage VLH at a connection between a capacitive non-linear load 8 and a load reactor 6 is detected and then the detected voltage VLH is multiplied by a compensation constant K(=-LA/LL) determined by an inductance value LA of a reactor 3 for suppressing a switching ripple and an inductance value LL of the load reactor 6 to generate a compensation voltage command. The compensation voltage command is PWM-modulated and is sent to a PWM converter 4. The PWM converter 4 then outputs compensation current ICH to compensate for the higher harmonic voltage VLH.