Comparative analysis of three-phase to five-phase transformer connections

Abstract

Five-phase supply is needed for supplying five-phase motor drive systems. Special transformer connection schemes have been developed over the years and reported in the literature to convert three-phase supply from the grid to obtain a balanced five-phase output which can be used to supply multiphase motor. In this paper, two existing transformer connections have been investigated and a new connection scheme has been proposed. Similar to the existing connection schemes, the proposed transformation system also employs three separate cores, each consisting of one primary and several secondary coils. The secondary coils comprise of different numbers of turns and are connected in specific ways so as to achieve the desired 72 degrees phase shift with equal magnitudes. The feasibility of the proposed scheme is proved using simulation and experimental approach. Moreover, a comparative analysis of the three solutions is presented.