Unified variable regularization factor based static compensator for power quality enhancement in distribution grid

•Implementation of unified variable regularization control algorithm in DSTATCOM.•Improvement in the power quality of distribution grid connected with nonlinear load.•Filtering of fundamental current components for switching of DSTATCOM.•Comparison of proposed control algorithm against the existing adaptive controls. A unified variable regularization factor based strategy for harmonic filtering at the supply side of the distribution system is presented in this paper. For this purpose, a three-phase distribution grid along with a distribution static compensator and a rectifier based nonlinear load is considered. A combined regularization affine projection sign algorithm-based control technique is used to calculate the weight values that denote the active power and reactive power segments of the load current. The proposed algorithm contains a variable mixing factor of two adaptive filters with different regularization parameters. The variable mixing factor enhances the tracking performance of the algorithm and hence it offers quick convergence and less steady-state error when compared with other affine projection-based filtering schemes. The control algorithm is evaluated under varying load patterns to derive its robustness and stability. Empirical assessment is carried out through real time simulation analysis aided by dSPACE-1202 controller. The performance of the applied control technique is found good-enough in mitigating the supply side harmonics and the total harmonic distortion levels rendered by the experimentation are in-line with the IEEE-519 standard.