Research On Model Predictive Control Based On New Energy Power Generation Inverter

With the rapid development of new energy power generation technology,the inverter control technology has been studied extensively.The new energy power supply can operate from the network independently and supply power to the load.It can also integrate the power generated into the power grid.When it connects to grid,it is necessary to consider that when the network voltage is unbalanced.During this case the output power of the new power source should be stable.For the power output of inverter,it is necessary to detect the harmonic content and provide the basis for subsequent management.In view of the above problems,combined with the Finite-Control-Set Model Predictive Control(FCS-MPC),the control strategy of NPC inverter under different conditions is applied.And a new harmonic detection method is proposed.This paper first introduces several traditional grid connected inverter control strategy.By comparing the advantages and disadvantages of various control strategies,the Finite-Control-Set Model Predictive Control(FCS-MPC)technology used in this paper is proposed.Subsequently,the system modeling,discretization methods,cost function establishment and computation delay problems are discussed in detail.For system discretization,this paper compares three different approaches.For the computation delay problem of FCS-MPC,the method of reducing computation time is given first,and then the delay compensation is carried out.Through simulation analysis,it can be seen that the improved FCS-MPC algorithm has better control effect when applied to the grid connected inverter.Then,considering the unbalanced grid voltage,the grid connected control strategy is proposed.Firstly,this paper introduces three kinds of phase-locked loop structure.The low tracking accuracy of traditional single reference coordinate system based on unbalanced power system is analyzed in detail.SOGI-PLL and MCCF-?? PLL are proposed to solve this problem.The MCCF-?? PLL is adopted to lock the phase of the grid voltage after comparing of simulation.After this,the power model of unbalanced network voltage is analyzed,and the corresponding control strategy is given by combining FCS-MPC with direct power control.Then,this paper analyzes the situation that the new energy generation directly supplies power to the load.Considering the load voltage requirements,a corresponding Finite-Control-Set Model Predictive Voltage Control(FCS-MPVC)is proposed.The above control strategy is verified by simulation.Then,this paper introduces a method of all phase spectrum analysis,combined with the Nuttall window function which has good sidelobe characteristics,propose a harmonic harmonic detection method of Nuttall double window improved all-phase Fourier algorithm.The robustness of the method is proved by numerical simulation.Finally,the experiment is carried out by the actual inverter system.The experimental results show that the proposed control algorithm and the detection algorithm in have good results.