Research on the symmetrical four-phase voltage produced by the three-phase four-bridge inverter

A novel method (AC-DC-AC) to produce symmetrical four-phase voltage is presented in this paper, The main circuit is the four-bridge topology and the control method is the three-dimensional voltage space vector control. This method has the merits of novel design, high conversion efficiency, good waveform quality and the method is easily to be realized.The power circuit topology of realizing four- phase power transmission is three-phase four-bridge arms inverter. In this paper, firstly, the four-phase inverter mathematical model is analyzed, via the analysis, the phase voltage and line voltage switching function expressions and their conversion matrixes are got, The method of describing four-phase symmetrical sine voltage with three-dimensional space vector is analyzed, four-phase / three-phase coordinate conversion matrix is derived, through the three- dimensional space vector analyses, these are reached: (a) The movement locus of four-phase symmetrical voltage parameters is a ellipse;(b) The control model of four-phase symmetrical voltage may be three-dimensional space vector pulse-width modulation, lastly, these proposed techniques have been verified by simulation and experimental results.