Application of a four-leg ASVG based on 3D SVPWM in compensating the harmful currents of unbalanced system

Contraposing the integrative compensatory issue of reactive current, negative sequence and zero sequence current in imbalanced power system, this paper describes a novel ASVG (advanced static VAr generator) scheme. The converter with four legs is adopted in the main circuit, and the dynamic model of ASVG including coupling transformer is given. Based on the i/sub p/-i/sub q/ method, the reference current signals are detected from load currents. Space vector modulation technology is adopted to control the ASVG and the algorithm of three dimensions voltage space vector modulation applicable to converter with four legs is developed. The simulation results prove the feasibility of four-leg ASVG and the validity of three dimensions voltage space vector modulation.