Model Predictive Control Method Of Three-phase Grid-connected Inverters

With the advancement of society,new energy technology is constantly developing and perfecting,and new energy grid-connected inverters and their control technologies are getting more and more attention from researchers in the field of power electronics.In this thesis,the three-phase L-type and LCL-type grid-connected inverters are studied,and the grid current tracking technology based on model prediction control is studied.Firstly,this thesis analyzes the working principles of three-phase L-type and LCL-type grid-connected inverters in detail,and mathematical models in three coordinate systems are established,and the parameters of the two filters are designed.Secondly,the finite control set model predictive control（FCS-MPC）is introduced in detail,and the establishment of discrete mathematical model,the design of cost function and online rolling optimization are described and analyzed.Aiming at the control delay problem faced by model predictive control（MPC）,a beat ahead control method was proposed as a delay compensation method.Then,focusing on the problem that MPC strategy relies too much on model accuracy and has poor robustness,the influence mechanism of line R and L parameter deviation of L-type grid-connected inverters,system equation discretization error of grid-connected inverters and sampling deviation on MPC current prediction deviation is analyzed.Based on this analysis,a model predictive control method based on prediction deviation correction is given.The deviation of LCL-type grid-connected inverters lines L₁,L_2,R₁,R₂parameters mismatch,the error caused by the discretization of the grid-connected inverter MPC model,and the deviation of the sampling process on the prediction deviation of MPC current mechanism.A model prediction control method based on predictive deviation feedback correction is proposed for LCL-type grid-connected inverters.This method can not only reduce adverse effects of parameter changes such as resistance and inductance on predictive control effects,but also restrain the deviation caused by system discretization and sampling deviation obviously.Finally,the simulation results of the three-phase grid-connected inverter model predictive control algorithm analyzed in this thesis were given,and the results verified the correctness of the theoretical analysis and the effectiveness of the control strategy given in the thesis.A three-phase L-type grid-connected inverter experimental platform was built,and the model predictive control algorithm of the three-phase grid-connected inverter analyzed in this thesis was verified.The experiments verified the correctness of the theoretical analysis and the effectiveness of the control strategy given in the thesis.This thesis has 59 figures,6 tables,and 95 reference articles.