An Integrated Interleaved Dual-Mode Time-Sharing Inverter for Single-Phase Grid-Tied Applications

In this paper, a novel integrated interleaved dual-mode time-sharing inverter (IIDMI) is proposed for grid-tied transformerless photovoltaic (PV) applications. While the dual-mode time-sharing conversion technique ensures minimum losses, the IIDMI also retains the advantages of interleaved topologies, such as low total harmonic distortion of the ac current with reduced filtering requirements, increased power density, and reduced current and thermal stresses of power devices. The leakage current problem, which is a main concern with the transformerless PV inverters, is solved by increasing the frequency of the main side band of the common-mode voltage above the resonance frequency of the common-mode impedance, while avoiding high switching losses. The current control, especially at transitions between the buck and the boost modes of operation, is highly improved by utilizing a fast-response deadbeat control scheme. The working principles of the IIDMI are explained in detail, and a 2.2-kW experimental prototype is implemented to confirm the theoretical achievements.