Novel Transformerless Single-phase Buck-Boost Inverter with Leakage Current Suppression Capability

Among various inverter structures, the proposed single-input Aalborg inverter topology is structured with only one photovoltaic array. The leakage current is completely eliminated due to the symmetrical topology. Besides, the control strategy based on dual-mode time-sharing can improve the conversion efficiency. In this paper, a novel buck and boost inverter with symmetrical structure, leakage current suppression capability and without transformers is proposed. In addition, the proposed inverter features a low number of semiconductor devices and maintains the original advantages compared with the single-input Aalborg inverter. The topology structure and its operating principle are analyzed in detail. The control strategy based on proportional integral (PI) control is designed in outer voltage loop and deadbeat control (DBC) is used for the current loop controller in the inner loop. Finally, the simulations based on PSIM have been constructed to verify the proposed topology and its control strategy.