Design & Simulation of Improved Active Power Filter for Renewable Energy Power Applications

Abstract

In this paper an active power filter implemented with a four-leg voltage-source inverter using a predictive control scheme is presented. The use of a four-leg voltage source inverter allows the compensation ofcurrentharmonic components, as well as unbalanced current generated by single-phase nonlinear loads. A detailed yet simple mathematical model of the active power filter, including the effect of the equivalent power system impedance, is derived and used to design the predictive control algorithm. The compensation performance of the proposed active power filter and the associated control scheme under steady state and transient operating conditions is demonstrated through simulations results. In recent times, fuzzy logic controller was applied for active power filter (APF) control application, as the APF is nothing but a current controlled VSI. In this project, a fuzzy logic based shunt APF is presented based on the effective time concept. The effective time concept eliminates the trigonometric calculations and sector identification, thereby it reduces the computational effort. Simulation results demonstrate the efficacy of the APF with the fuzzy logic based control strategy. Simulation results are obtained for both predictive control scheme and fuzzy logic controller and the results are care compared. The response time for compensation is 0.02sec. Computer simulation by MATLAB/ SIMULINK has been used to support the developed concept.

Keywords: Active power filter; current
control; four-leg converters; predictive control; Fuzzy logic controller