DC-link voltage control and performance analysis of StatCom

The introduced control strategy in this paper is about the control of reactive-power, which flows through the transmission line, and the DC-link voltage, which is regarded as inner control loop for a desired level to produce a stable output-voltage magnitude and corresponding phase-angle of inverter. With this control strategy the control system can easy output reactive-power to system or absorb reactive-power from system, and hence, stabilize terminal-voltage for a distribution power system. The reactive dynamic characteristics are discussed as load-property varies abruptly from inductive to capacitive, or put of and/or put on inductive load. Especially, the transition processes of voltage and current of power elements are described in detail.