Modified modeling and system stabilization of shunt active power filter compensating loads with µF capacitance

Abstract

The interactions between shunt active power filter (APF) and capacitance load tend to result in stability problems and resonance. The conventional model of a shunt APF is not precise enough to reflect this phenomenon. To address it, this paper proposes a modified shunt APF system model to accurately reflect various stability problems. This paper also studies the mechanism of positive feedback resonance brought by capacitance load and proposes a modified hybrid controller to improve the stable margin of the system, making the shunt APF work stably under different working conditions where there are µF capacitors on the demand side. The correctness and validity of the proposed strategy are verified by simulation analysis and prototype experiments.