Three-Level 24-Pulse STATCOM with Pulse Width Control at Fundamental Frequency Switching

This paper presents a control methodology of a three-level 24-pulse STATCOM (Static Synchronous Compensator) with pulse width control at fundamental frequency switching and maintaining constant dc voltage. Four units of three-level neutral point clamped VSCs are used to form a quasi three-level 24-pulse STATCOM. In each three-level VSC, the pulse width of positive and negative cycles is modulated to obtain a voltage of controlled magnitude which in turn controls the reactive power of the STATCOM. A decoupled current control algorithm is used for the control of the STATCOM. The proposed model of the STATCOM is developed using MATLAB/Simulink SimPowerSystems toolboxes. The STATCOM is connected to a 132 kV, 60 Hz ac system and simulation results are presented to demonstrate its dynamic performance.