Combined Variable Step Size LMS for DVR with Error Regulator Gain Tuning Through Ant-Lion Optimization

In this paper, the dynamic voltage restorer (DVR) performance is enhanced with the combined variable step-size least mean square (CVSSLMS) and optimized PI (Proportional-Integral) regulators-based control algorithm. Multiple voltage disturbances in distribution network like voltage sag, swell, voltage imbalance, and distortions are taken into consideration for compensation using DVR. The CVSSLMS has the combined features of both Normalized LMS (NLMS) and LMS algorithms such as effective transient response and reduced steady state error, respectively. In internal structure of algorithm, PI controllers are used as error regulator to regulate dc and ac bus voltages through error minimization technique. The PI controller gains are tuned through an optimization algorithm named as ant-lion optimization (ALO) algorithm. The added feature of ALO is the avoidance of local optimum. With this control algorithm, the performance of three phase DVR is simulated for the aforesaid disturbances using MATLAB/Simulink model. It is also experimentally tested using DSP (Micro Lab Box, made by Free scale QorlQ P5020) in three phase distribution networks. It is observed that, in both cases, the performance has met the requirement according to the IEEE-519-2014 standard.