Research on static reactive power generator based on asymmetric distribution network

Abstract

Negative or zero sequence components are generated when the voltage is asymmetric or harmonic in distribution networks. Meanwhile, the decoupling process of traditional dq transform is complex. To solve the above problems, firstly, the T/4 delay method (T is the period of grid voltage) is presented to separate positive and negative sequence components, which improves the stability of software phase-locked. Then, software phase-locked loop (SPLL) is designed to ensure the instantaneity of reactive current check. Besides, a double-loop control scheme combining proportional integral (PI) controller for DC voltage in outer loop and proportional resonance (PR) controller for AC current in inner loop without decoupling is designed by considering the characteristics of traditional PI and PR without static error regulation. It avoids the complicated decoupling process and improves the real-time performance of the system. Finally, both simulation and experimental results are given to verify the feasibility of design scheme in the static var generator (SVG) system by MATLAB/Simulink and experimental platform based on DSP28335.