The Design Of Single-phase Photovoltaic Grid-connected Inverter Based On MATLAB

In this paper,the 5KW single phase series photovoltaic inverter is the main research object.With the goal of lower output harmonic,higher conversion efficiency,and more stable operation,the single phase series photovoltaic inverter is divided into two main research directions:(1)Photovoltaic array maximum power point tracking(MPPT)technique(2)design of the Control strategy of grid connected inverter.1.It is necessary to study the maximum power point tracking technology for photovoltaic array.First of all,it is requisite to analyze the working principle of the battery and establish mathematical model.And then the MATLAB simulation model is built for a single photovoltaic cell.Finally,the simulation model of the photovoltaic array is established for the multi wave crest of the output characteristic of U-P.2.For the maximum power point tracking technology for photovoltaic array,the key is how to raise the speed of MPPT tracking and prevent tracing from entering local optima.In view of the above two issues,it has the discussion of the traditional MPPT method.And then the MPPT method based on particle swarm optimization(PSO)is introduced to overcome the shortcomings of local optimization.Finally,the MPPT method based on Particle Swarm Optimization(PSO)is proposed to overcome the shortcomings of the method,analyzing the operating principle,building the simulation model,analyzing the simulation results,and proving that the method can quickly and accurately track the PV system to the maximum output point.3.The design of filtering link for single phase series photovoltaic inverter.First of all,there is the comparison of L type,LC type,LCL type filter in this paper,introducing the superiority of LCL filtering.And then the limitation of LCL filter design is analyzed.Finally,the parameters of the LCL filter are selected for the 5KW single-phase inverter selected in this paper.4.For Control Strategy of Photovoltaic Grid-connected Inverter,the control structure and mathematical model of single-phase grid-connected inverter are briefly introduced at first.The working principle of voltage feed-forward is introduced subsequently.Then the principle and deficiency of voltage feed-forward are analyzed.And then several classical controllers are introduced,including PR controller and quasi PR controller,and analyzing the advantages and disadvantages of these controllers.Finally,a quasi-proportional resonant controller with harmonic compensation is introduced.Firstly,the source of the low harmonics in the output current is analyzed before the specific introduction.And then the quasi-proportional resonant controller with adding harmonic compensation,and the difference between the quasi-proportional resonant controller and the quasi-proportional controller and the use of scenes are introduced.Finally,the parameters of the controller are designed.At the end of the paper,the simulation model of the photovoltaic system is established through the Simulink simulation module.Verifing the advantages of the proposed method,structure design and parameter design.It analyzed the harmonic of output current,and then it compared with the traditional control strategy.The experimental verification is carried out in this paper.