Optimization of controller gains to enhance power quality of standalone wind energy conversion system

Abstract

Abstract This article presents optimized gains for regulation of frequency and terminal voltage irrespective of the varying wind speeds in an autonomous wind power generation feeding linear and non-linear loads. Icosφ control algorithm is used to calculate and estimate reference source currents in a remote area wind energy conversion system (WECS) using an Induction Generator (IG). The Icosφ control algorithm do not have any phase locked loop or any conversions from one reference frame to other, which improves the dynamics and power system quality issues. The heart of the control algorithm is how quickly it estimates the reference source currents; this in turn depends on values of proportional and integral controller gains in the control algorithm. Here we are applying three optimization techniques to find the optimal proportional-integral (PI) controller output gains, the best convergence values are taken from optimization technique and applied for WECS. Battery energy storage system (BESS) connected to the direct current (DC) link of voltage source converter (VSC) manages the power of WECS. When load useful power level is less than the generated power level, the excess will be diverted and stored in the battery. But when generated power level is less than the load applied on WECS then the excess power requirement of the load is met by the battery, thus regulating the frequency under varying wind speeds. An isolated zigzag transformer is connected between point of common coupling and controller for neutral line current compensation. The controller is used for load balancing, current harmonic suppression, voltage and frequency regulation.