Topology and Control Strategy of a Single-Phase Buck-Boost Five-Level Inverter

In this paper, a new single-phase five-level inverter topology with buck-boost capability is proposed by analyzing the advantages and disadvantages of the existing five-level inverter topology. Compared with the traditional multilevel inverter topology, the new Buck-Boost five-level inverter has the advantages of enabling buck-boost, simple topology, easy control, less power devices, and low switching losses. Under the carrier cascade modulation strategy, an open loop simulation was performed on the new inverter to verify the Buck-Boost capability. Based on the PR control, the closed-loop design of the new inverter was performed and verified by simulation. In order to improve the quality of the grid-connected current, the model predictive control algorithm was used to control the inverter, and Matlab simulation was performed to verify the correctness of the theoretical analysis. Compared with the traditional PR control methods, this control method has the advantage of model prediction. Finally, the open-loop and closed-loop experiments have verified the new inverter topology. © 2019, Electrical Technology Press Co. Ltd. All right reserved.