| 摘要 |
PURPOSE:To provide the higher harmonic current suppressing means for the capacitor for power factor improvement which can reduce a higher harmonic current flowing in the capacitor for power factor improvement, an existent equipment, even if the voltage VS of a system power source contains higher harmonics. CONSTITUTION:An active filter 7 is connected in parallel to the capacitor 4 for power factor improvement provided in a power distribution system and a control unit 9 for the active filter 7 is equipped with a current detector 121 which detects the resultant current ISC of the active filter 7 and capacitor 4 for power factor improvement; and the current detector 121 has a resistor 122 for current detection and means 123 and 124 which perform second order differentation of the outputs of the resistor to suppress the higher harmonic current, thus obtaining the higher harmonic current suppressing method for the capacitor 4 for power factor improvement. |
