An adaptive hysteresis band controller for LC-coupling hybrid active power filter with approximate constant switching frequency

This paper presents an adaptive hysteresis band controller for LC-coupling hybrid active power filter (HAPF) which can provide an approximate constant switching frequency. As the LC-coupling impendence can yield nonlinear compensating current slope, the conventional adaptive hysteresis band controller for linear L-coupling system like active power filter (APF) cannot be directly applied to nonlinear LC-coupling HAPF system. Owing to the circuit configuration of HAPF, its compensating current characteristic is firstly analyzed and discussed. The adaptive hysteresis band current controller for HAPF is then proposed by considering its nonlinear characteristic. Finally, to verify the performance of the proposed adaptive hysteresis band controller, simulation results are given in comparison with both conventional adaptive hysteresis band controller (developed for L-coupling system) and fixed hysteresis band controller for HAPF.