A new switched inductor VAR compensator

A new circuit configuration for the generation of both reactive power and harmonic current is presented. Unlike Thyristor Controlled Reactors (TCR), the voltage across an inductor is pulse-width modulated in such a way to produce the required line current. In this presentation the switched inductor is producing lagging reactive power. In conjunction with a fixed parallel capacitor, good quality variable leading and lagging reactive power can be generated. The modulation of the voltage across the inductor is achieved by two semiconductor switches. A relatively high switching frequency is used shifting the line harmonics to a high order for ease of filtering. The size of the passive filters is potentially reduced bringing the cost and size of the system to more attractive levels. The switching frequency and choice of switching semiconductors can be optimized to keep efficiency high. The Switching Function technique is used throughout to analyze the circuit using Mathcad. A PSPICE model is constructed and an experimental set up is presented. PSPICE circuit and Switching Function PSPICE simulations are presented to support the theory.