An Improved Control Algorithm for DSTATCOM Based on Single-Phase SOGI-PLL under Varying Load Conditions and Adverse Grid Conditions

This paper introduces an improved control algorithm based on single-phase SOGI (Second Order Generalized Integrator) for the generation of DSTATCOM (Distribution Static Synchronous Compensator) reference currents. In a distribution system, DSTATCOM serves as an optimal choice for power quality compensation. The power quality (PQ) compensation under adverse grid conditions and varying load conditions relies entirely on the control algorithm. In this controller, estimation of peak value of load currents and unit template generation are done based on single-phase SOGI. This makes the controller simpler, reliable and ease of implementation in real-time applications. Power quality improvement using conventional compensation methods has many disadvantages like fixed compensation, resonance, high computational burden, electromagnetic interference etc. The proposed algorithm for DSTATCOM is aiming to perform with dynamic compensation and low computational burden for low-end processors with accurate tracking performance under distorted/step changes in load currents and to provide good compensation with load balancing and harmonic elimination. In this paper, SOGI-PLL is adopted because of its dynamic performance, speed and tracking accuracy under all varying and distorted conditions. The effectiveness of the proposed controller developed and tested using MATLAB/Simulink and the results found satisfactory.