Fuzzy logic-based instantaneous power ripple minimization for direct power control applied in a shunt active power filter

The high presence of instantaneous active and reactive power ripples when using the direct power control (DPC) strategy in power converters represents a serious issue, especially when used in active power filters (APFs) to compensate harmonics; those ripples are due to the presence of hysteresis controllers and the rigidity of the conventional switching table, and they cause serious limitations in the filtering capabilities of APFs. Many attempts had been proposed to solve this problem, but at the expense of over-complicating the DPC. In this paper, we tackle this problem by shifting toward a fuzzy logic paradigm and creating a fuzzy inference system that replaces the hysteresis controllers and the switching table, and the goal is to reduce the rigidity of the conventional DPC and build a smoother alternative, which will result in less power ripples. The proposed strategy is tested using MATLAB simulations and experimentally validated using an FPGA-based laboratory setup during both steady-state and transient conditions.