Optimisation‐based improved switching technique for static VAr compensator considering minimum source harmonic injection

Abstract

A selective harmonic elimination and minimisation-based improved switching technique is proposed for static VAr compensator (SVC) considering minimum source harmonic injection without external filter. Fixed capacitor–insulated gate bipolar transistor controlled reactor (IGBTCR) is used for the proposed SVC model. The switching function of IGBTCR is optimised for minimum reactor voltage total harmonic distortion (THD) which leads to less harmonic injection to line resulting minimisation of source current THD. The best possible optimised switching angles are computed offline using gravitational search algorithm with varying modulation indices to obtain minimum reactor voltage THD. Piecewise mixed model approximation technique is used to store these switching angles as a function of modulation index in the processor memory for online application. The proposed switching significantly improves source current THD compared to conventional switching. Proper simulations as well as experimental results are presented to confirm the proposed scheme.