Enhancing performance of active power filter with fuzzy logic controller using adaptive hysteresis direct current control

Active power filters (APFs) are widely accepted power electronic devices for compensating harmonic currents produced by nonlinear loads. The conventional technology used for APFs is a proportional-plus-integral (PI) controller. However, both the conventional approaches for determining the PI coefficients and also its structure may not provide satisfactory results under transient operating conditions such as a sudden change of load. Therefore, this paper proposes a proportional-integral-derivative fuzzy logic controller (PID-FLC) to improve the steady-state and transient performances of the conventional APF controllers. First, particle swarm optimization (PSO) is utilized to determine the optimal coefficients of the proposed PID-FLC. Then, the direct current control approach is used to generate the reference harmonic signals from the non-sinusoidal load current while an adaptive hysteresis-based current control is selected to control the compensating currents. Simulation results for a power system connected to a nonlinear load are generated to investigate the dynamic performance of APF equipped with the conventional-PI (C-PI), optimized-PI (OPT-PI), optimized-PID (OPT-PID) and optimized-PID-FLC (OPT-PID-FLC) controllers using MATLAB/SIMULINK software.