Research On Main Circuit Of STATCOM Based On IGCT

The problem of electric energy quality menaces seriously the safe operation of power network, especially reactive power and harmonics. As a new Var compensator, the Static Synchronous Compensator (STATCOM) attracts extensive attention for its perfect performance such as smooth regulation of Var and dynamic capability.In this dissertation, the main circuit of 6kV/200kVA STATCOM is lucubrated. Firstly the basic operation principle and the method of control of STATCOM is expatiated. Then, this paper respectively compares the advances and defects of four kinds of the multilevel main circuit ,that are multiple main circuit of transformer , diode-clamped multilevel , flying-capacitor multilevel and cascade multilevel. The configuration and the basic operation principle of multiple main circuit of transformer and cascade multilevel are analyzed in detail. A improved method on Selected Harmonic Elimination PWM based on cascade multilevel is proposed in this paper. In this method, the switching frequency of each switching component is the same. The method of obtaining initial values by adding single H-bridge switching angles is presented for non-linear SHEPWM equations. The operation principle and new technology of IGCT is discussed. According to the project request , the parameter of other important components are designed.At last, the simulation model based on multiple main circuit of transformer and cascade multilevel about the main circuit of STATCOM are completed with MATLAB respectively. And the simulation result is presented to verify the correctness and feasibility of research on main circuit in this paper.