Optimization of APF LCL output filter based on genetic algorithm

The active power filter (APF) utilizing the pulse width modulation (PWM) technology generates high frequency switch harmonic current, which is leaked into the power grid and must be eliminated by output filter. Because of the excellent filtering performance of LCL while grid impedance fluctuating, the LCL filter is adopted as output filter in APF. Thus, the mathematical model of LCL type output filter in APF is constructed. For consuming problem caused by damping resistance, a LCL filter active damping method based on introducing capacitor current feedback is presented, which can enhance the damping equivalently and avoid current resonance. Simulation and experimental results justify the active damping method. On the basis of above research, synthetically considering the compensation performance of APF and filtering performance of LCL output filter etc, the optimization model of LCL filter and optimization method based on genetic algorithm are presented. Optimized LCL filter can not only eliminate switch harmonic effectively but also enhance the compensation ability of the APF.