A novel single-phase transformerless dual-mode interleaved multi-level inverter (DMIMI) is proposed, which can inject a highly sinusoidal AC current to the grid even with the input DC voltage less than the peak grid voltage. Furthermore, dead-beat controllers are developed to directly calculate the optimal duty cycles in a digital control platform. As compared to the traditional dual-mode multilevel approaches, the DMIMI offers a high efficiency, less number of components conducting simultaneously in each operation mode and the capability of reactive power exchange. The paper presents the theoretical analysis and the experimental results obtained from a 1 kW prototype. The experimental results reveal that the proposed DMIMI can achieve a high conversion efficiency and a low leakage current as well as a high quality grid current.

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