Generalized Instantaneous Power Theory and its Application to Series Hybrid Active Power Filter

Abstract: Harmonic injection in supply current is most common problem arising in supply network because of the increased population of nonlinear loads. Traditionally used standalone passive and active filters have some practical drawbacks which can be overcome by hybrid active power filters (HAPF). HAPFs inherit the efficiency of passive filters and the improved performance of active filters. Here filtering characteristic of passive filter is improved by the active filter. A combined system of passive and active power filter is practically used to minimize the harmonic currents and voltage as well as to improve the power factor of the ac mains. The choice of nonlinear load, supply network parameters and the control algorithm determines the performance of HAPF. This paper presents the HAPF topology which combines series active power filter (SAPF) and shunt passive filter. Generalized Instantaneous Power Theory (GIPT) is used as a control algorithm. The HAPF configuration is tested for harmonic elimination of 28 kVA non linear load. Performance parameters like source current THD, load current THD, load voltage THD and required inverter ratings are analysed during the operation of HAPF. The transient performance is also tested and presented via simulation.

Keywords: active power filters, passive filers, HAPF, THD, FFT analysis.