Active Power Filter Design by a Novel Approach of Multi-Objective Optimization

This paper presents an innovative active power filter design method to simultaneously compensate the current harmonics and reactive power of a nonlinear load. The power filter integrates a passive power filter which is a RL low-pass filter placed in series with the load, and an active power filter which comprises an RL in series with an IGBT based voltage source converter. The filter is assumed to inject a current into the connection node of the load and grid to eliminate current harmonics and its reactive part. The voltage source converter is placed in a hysteresis feedback control loop to generate a harmonic current. The bandwidth and output amplitude of the hysteresis controller are optimized with the inductance of RL filters. Three objective functions are considered in the optimization problem, which include minimizing of current total harmonic distortion, maximizing of power factor, and minimizing of the IGBT bridge current. For solving the optimization problem, two well-known multi-objective evolutionary algorithms are applied, namely, non-dominated sorting genetic algorithm-II (NSGA-II) and Strength Pareto Evolutionary Algorithm ۲ (SPEA۲). Test results showed that the SPEA۲ technique exhibited a better performance in comparison to NSGA-II relative to the objectives.