A novel variable reactor based on an inverter-controlled transformer

In the paper, a novel adjustable reactor is proposed. In the novel reactor, a transformer with air gap is chosen and its primary winding is connected in series or parallel to the power system, the primary winding voltage is detected and passed to a phase shift circuit. The output signal of the phase shift circuit functions as the reference signal. A voltage-source inverter (VSI) is applied to produce a controllable voltage source, which is energized across the secondary winding of the transformer. The equivalent impedance of primary winding varies continuously along with the amplitude of the secondary voltage and phase shift angle. Besides this, the stability condition is analyzed. The validity of the theory is proved by the simulation results.