Research On Topology And Control Strategy Of A New Single-phase Buck-boost Five-level Inverter

In the process of wind energy utilization,the inverter is the key link of wind power generation system.With the level of voltage and power have been improved,the traditional two-level inverter is difficult to meet the need of actual industrial production.Therefore,multi-level inverter technology has been proposed.Research on multi-level inverters mainly focuses on the topology and the control strategy.In this paper,by analyzing the advantages and disadvantages of the existing five-level inverter topology,a new single-phase five-level inverter topology with buck-boost capability is proposed.Based on PR control and MPC control,the closed-loop system is designed and compared.Firstly,the topology and working principle of the new buck-boost five-level inverter are briefly introduced.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,low power devices,and low switching losses.Under the carrier cascade modulation strategy,an open loop simulation is performed on the new inverter to reflect the buck-boost capability.Based on the PR control,the closed-loop design of the new inverter is performed and verified by simulation to prove the feasibility of the topology.Secondly,in order to improve the quality of the grid-connected current,the model predictive control algorithm is used in this paper to control the inverter.The control principle and control flow of the model predictive control algorithm are introduced in detail,and MATLAB simulation is performed to verify the correctness of the theoretical analysis.Finally compared with the traditional PR control methods to highlight the advantages of model prediction.Finally,the drawing of the printed circuit board is performed,and the main circuit and the control circuit are soldered to complete the experimental platform based on the structure of the new buck-boost five-level inverter.The program is written with TMS320F2812 as the core.Open-loop and closed-loop experiments are performed on the new inverter.