Performance analysis of a PWM inverter VAr compensator

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 computation of the associated reactive power component. A mathematical model for the compensator connected across a variable power factor load is derived. The frequency response is obtained for open-loop operation. This allows the design of the controller. Predicted results are verified experimentally for both open and closed-loop responses