Fixed-band fixed-frequency hysteresis current control used In APFs

A practical concern with implementing the fixed band hysteresis current control in active power filters (APF) is its variable switching pattern that results in increasing the risk of occurrence of resonance in power systems. To avoid this situation, adaptive hysteresis current control methods with the variable hysteresis bands have been recommended in literature. However, these methods impose an absolutely huge amount of complex computations on the system which, in turn, slows down its response time and thereby, limits the switching frequency. This paper devises a novel fixed-band fixed-frequency (FBFF) hysteresis current control strategy that aims to eliminate completely the mentioned calculations while keeps merits of the adaptive methods. In other words, the suggested strategy employs an algorithm that is similar to the fixed-band variable-frequency hysteresis methods; however, the outcomes are identical to the variable-band fixed-frequency hysteresis current control techniques. Employing the proposed FBFF method to control an APF leads to an accurate modulation performance with the least possible calculations required in a filtering procedure. Several simulations are done using MATLAB/Simulink to verify validity of the proposed method.