| 摘要 |
PURPOSE:To enable continuous operation by inputting effective and reactive components of load current through an absolute value circuit to a multi-stage hysteresis comparator and regulating the gain of a digital signal obtained through conversion according to the amount of overload. CONSTITUTION:First and second absolute circuits 21a, 21b provides absolute values of effective and reactive component signals ip, iq of load current to an adder 22 where they are added, and an adder/subtractor 23 inputs a differ ence value signal between the sum and a current limit value limit to a multi- stage hysteresis comparator 25 through a proportional integrator 24. The multi- stage hysteresis comparator 25 converts the difference value signal into a digital signal corresponding to the amount of overload, whereafter data is read out from a ROM 26 according to the digital signal and fed to first and second multiplier type D/A converters 27a, 27b. A second function generator 17 performs coordinate conversion of voltage phase based on effective and reactive components ip', iq' of regulated current and outputs a higher harmonic compen sated command current signal i* for an active filter. |
