Design, analysis and simulation of linear controller of a STATCOM for reactive power compensation on variation of DC link voltage

The STATCOM (STATic synchronous COMpensator) is a shunt connected voltage source converter using self-commutating device and can be effectively used for reactive power control. Its principle of operation is similar to that of a synchronous condenser. This paper describes the modeling of STATCOM along with the design of linear current and voltage controllers. The design of controllers for the converters can be realized in two ways. The first method is a non-linear realization, which results in simple control rules with faster dynamics. The second method is a linear method, which requires system modeling. The second approach is adopted and simulated waveforms are presented in the paper. The designed controllers with variation of DC link voltage have been applied to the STATCOM and suitable DC link voltage has been selected on basis of spike and over shoot of the responses. All responses are obtained through MATLAB SIMULINK tool box and presented here for clarity of the control strategy.