The research on special electronic power transformer

Abstract

In many circumstances, three-phase AC power supply is not always the best choice for utilityapplications. In fact, there is a rating of three-phase to single-phase, three-phase to dual-phase andthree-phase to multiphase transformers being in operation around the world, which are almost allmade by general means. In spite of their huge cubage and weight, those transformers have other fatalcharacters for instance they can spread a fault current. EPT (Electronic Power Transformer, alsocalled Power Electronic Transformer or Solid Transformer) has been proposed for years. In thispaper, we use a module composed of the input three-phase PWM (Pulse Width Modulation) rectifier,medium frequency transformer and output single-phase inverters to structure a series of functionSEPT (special EPT). We also discussed the modulation strategies of the SEPTs in this paper, andwhat's more, we expand the PARK transformation to four-phase and firstly proposed thetransformation coefficients of four-phase AC system to dqg0 system. Several cases are beingdiscussed in this paper, and the results of the simulation proved that SEPT has all the advantagesEPT has, such as better steady-state, better waveforms, better power factor etc. compared withgeneral special transformers.