Grid-connected Design Of Full-bridge Three-level Inverter Based On Improved Finite Control Set Model Predictive Control

Global industrialization has caused energy crises and environmental pollution,it is imperative to develop and utilize clean energy.In the process of using clean energy,the inverter is a key part of the grid connection of the power generation system.The traditional two-level inverter is not suitable for high-voltage and high-power applications,and the output voltage harmonic is high.In contrast,multilevel inverters are more suitable for photovoltaic power generation systems.The control strategy also affects the performance of grid-connected inverters.Model predictive control is a new type of control method with good dynamic performance and robustness,and can handle multiple constraints flexibly.In order to improve the performance of inverter grid-connected,a grid-connected system with finite control set model predictive control is designed.The main work of this paper is as follows:Firstly,the topology and working principle of the full-bridge three-level inverter are introduced.The causes of the neutral point voltage imbalance of the inverter are analyzed in detail,and the corresponding control strategies are proposed.Secondly,a grid-connected system based on finite control set model predictive control is designed.The principle and design process of the control algorithm are introduced in detail.Compared with PI control and deadbeat control,it proves that FCS-MPC has good performance and can meet the requirements of grid connection.The traditional finite control set model predictive control has defects in practical applications.In this paper,the method based on predictive current further forward prediction is used to solve the driving signal delay problem.The prediction model based on the expected voltage is used to reduce the number of calculations of the prediction model and the cost function.Finally,on the basis of theoretical analysis and simulation,the experimental prototype of the full-bridge three-level inverter is built,and the control program is written with TMS320F28335 as the core.The open-loop and closed-loop experiments are carried out to verify the correctness of the theoretical analysis.