Control of DSTATCOM with Parallel Tangent Method Based Adaptive Control Algorithm under Distorted Grid Conditions

Abstract

This paper presents a new adaptive control algorithm for a cascaded multilevel inverter (CHB-MLI) used as a Distribution Static compensator (DSTATCOM) unit to mitigate various power quality (PQ) issues. A Parallel Tangent (PARTAN) Least Mean Square (LMS) adaptive control algorithm controls the compensator. The shunt CHB-MLI exports reactive power needed by the nonlinear load and improves the power factor to unity on the supply side. The system’s closed-loop performance is also studied under a distorted grid employing an additional Second-order generalized integrator (SOGI) block. Modeling of a five-level inverter along with the proposed PARTAN-LMS controller has been done in Matlab/Simulink. Experimental verification of the same system is tested in the laboratory. Simulation and experimental results demonstrate satisfactory performance of the proposed system under dynamic load variation and distorted grid conditions. Further, the performance of the proposed algorithm is compared with conventional and new adaptive algorithms to ascertain its advantages and effectiveness. The THD obtained in supply current and voltages are within stipulated IEEE-519 limits.