Generation of voltage reference signal in closed-loop control of STATCOM

Power theories are used to develop reference signals for FACTS applications such as voltage regulation and/or power factor correction. These signals are generally generated in current waveforms that are either absorbed or injected to a power system. Current oriented modulations (e.g. hysteresis strategy) are basically fast and simple, but variable high switching frequencies lowers efficiency of the controllers. Since high power applications need very high efficiency, fixed low switching frequency is preferred. This can be achieved if reference voltages are available. Voltage references can be modulated using sinusoidal PWM or space vector modulation (SVM). This paper proposes a closed-loop control for voltage regulation using the average model of STATCOM. The whole system is simulated to verify the suggested method, including the average model along with the engaged control and modulation techniques.