Modelling and analysis of three-phase hybrid transformer with buck-boost matrix-reactance chopper and active load

This paper deals with a three-phase power system with hybrid transformer (HT). The HT contains a conventional transformer with electromagnetic coupling and PWM AC line chopper integrated with the secondary windings through an electric coupling. The HT uses a three-phase Yy connected transformer with additional secondary windings and three-phase PWM AC line chopper with buck-boost topology. The paper gives a description of the three-phase power system with hybrid transformer (HT) and unsynchronized active load, as well as the mathematical and circuit models of the AC source with HT. The analysis of basic steady state properties of these models are verified by means of the simulation and experimental test results obtained for the power system with HT of about 6 kVA.