Low Losses Hysteresis Current Control Method for Active Power Filter

In this paper a novel hysteresis current controller for APF(active power filter) with low switching losses is suggested. The controller adjusts the switching frequency with the output current of APF to reduce the switching losses effectively with the same control precision, utilizing the characteristic of APF that the sum of absolute value of three-phase output current of APF would greatly fluctuate in a cycle because it is mainly composed of harmonics currents. The related concept and formulation are presented. Computer simulation is conducted on a testing system with PSCAD/EMTDC program and the results show that the controller can effectively reduce the switching losses with the same current tracking error.