DC-link voltage control and performance analysis of StatCom

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