Design, analysis and simulation of small signal control strategy of a STATCOM for reactive power compensation on variation of DC link voltage

The STATCOM (STATic synchronous Compensator) is being increasingly popular in power system applications. In general, reactive power compensation for power factor and stability of the utility system can be improved. A simple dq transformation and steady state and transient analysis are achieved to characterize the open loop system. A control scheme of the STATCOM has been proposed without controlling DC link voltage. The small signal scheme controls the phase angle as well as modulation index of the switching pattern and with small perturbation of reference current (reactive current of load), the DC voltage nearly remains constant. On variation of DC link voltage, the spike and overshoot of the responses have been studied and suitable DC link voltage has been selected. All responses are obtained trough MATLAB simulink tool box and presented here for clarity of the control strategy.