In multi-module inverter systems, phase-shifting transformers are needed to compose non-sinusoidal voltages into staircase waveforms approaching sinusoid. Aiming at the drawbacks of normal phase-shifting transformers with respect of installation and operation, the paper proposes a novel transformer of round shape resembling induction motor. Contrast to the normal phase-shifting transformers, the iron core of the novel one is more compact and symmetrical, and the windings distribution and connection are simpler. Focusing on novel transformer of dual Y/ Y, the paper theoretically proves that harmonics of the 5th, 7th etc. are eliminated from the composed magneto motive force (MMF). Mathematic model of the novel transformer is set up and simulated numerically for exhibiting the main performance.