A control method of hybrid filter for continuous reactive power compensation in a substation

This paper presents a control strategy of hybrid active filter for continuous reactive power compensation. The hybrid active filter operates as an equivalent adjustable capacitor in series to the filter inductor. The equivalent capacitance can be tuned to specific value without connecting extra capacitors. When the equivalent capacitor varies, the characteristic of circuit will be modified, including the resonance frequency of the passive filter. Theoretical analysis and experimental results are given to verify effectiveness.