Analysis and controller design of static var compensator using three-level GTO inverter

Abstract

A static var compensator (SVC) using three-level GTO voltage source inverter (VSI) is presented for high-voltage, high-power applications, The three-level VSI has lower harmonic components and higher dc-link voltage than the two level VSI and thus can be operated at lower switching frequency (f(sw) < 500 Hz) without excessive harmonic contents, From the DQ-transformed equivalent circuit of the presented SVC system, DC and AC analyses are carried out to know the steady state and the dynamic characteristics of the system, Based on the open-loop transfer function of the system, a controller is designed to achieve fast dynamic response, The experimental results confirm the theoretical analyses and controller design.