Abstract：In multi-module inverter systems, phase-shift transformers are needed to compose voltages of square waveform into voltages of staircase waveform. To improve the constructional and electric performance of the normal phase-shift transformers, a novel transformer constructed in round-shape is proposed. Contrast to the normal phase-shift transformers, the iron core of the novel transformer is more compact and symmetrical, and the windings construction and connection are simpler. Focusing on a dual Y/ Y transformer of round-shape, the paper theoretically proves that the 5th, 7th et al. Harmonics are eliminated from the composed magnetomotive force(MMF) and numerically analyzes the characteristics of magnetic fields produced by harmonic currents. Mathematical model of the novel transformer is set up and the main performance is analyzed by simulation. Finally, based on system of multi-module inverter, validity of the novel transformer is verified, and its main performance is analyzed experimentally.
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2012, Vol. 27 
