Power electronic zigzag transformer for experimental voltage generator

This paper presents a mid-voltage experimental voltage generator used for the testing mainly of distribution power equipment, high-power drives and renewable power generation. It utilizes thyristor-controlled zigzag transformer as its primary circuit. Based on the analysis of the operation mechanism, the voltage equations are derived and control strategy is proposed. This power electronic zigzag transformer is capable of providing various experimental voltage conditions, including voltage swell, voltage sag and phase angle change. It has more rapid and accurate response than impedance-type voltage regulators and has lower cost and less footprint than back-to-back voltage source converter. Simulation model is developed with PSCAD software and simulation results validates the proposed schemes.