A solid state VAR compensator with fast dynamic response

The performance of a three-phase solid-state reactive power compensator with fast dynamic response is analyzed. The compensator consists of a three-phase pulse-width-modulated voltage-source inverter connected to a self-controlled DC bus. The principal advantage of this scheme is that it can maintain a near-unity source power factor without sensing and computing the associated reactive power component. It can also substantially reduce the harmonic content of the input line current when the load is nonlinear. A mathematical model for the compensator connected across a variable power factor load is derived. The frequency response is obtained for open-loop operation which allows for design of the controller. Predicted results are verified experimentally