A solid-state high-performance reactive-power compensator

A high-performance reactive-power compensator is presented and analyzed. The VAR compensator consists of a three-phase current-regulated pulse width modulated voltage-source inverter connected to a self-controlled DC bus. Reactive-power compensation is achieved by forcing the inverter output current to follow a reactive sinusoidal reference waveform at a constant switching frequency. The main advantages of this scheme are that it reduces the stresses on the switching devices (as compared with other current regulated techniques), and it has a fast response time, which allows almost instantaneous reactive current control, and low harmonic distortion in the line currents. In particular, the authors discuss the proposed scheme in terms of principles of operation, power and control system design, and the analysis under transient operating conditions. Simulated results obtained with the Spice simulating package for steady-state and transient operating conditions are presented and validated on an experimental unit