Research On Photovoltaic MPPT Algorithm And Controller Design Under Partial Shading

With the increasing demand for energy and the worsening environmental problems,people have great interest in the use of renewable energy.In the process of photovoltaic power generation,uneven illumination or partial shading of photovoltaic modules is an inevitable problem in photovoltaic power generation system.Array mismatch and hot spot caused by shadow not only seriously affect power generation efficiency,but also bring safety and reliability problems.Affected by this,the PV array's output P-V characteristic curve no longer shows a single peak,but a multi-peak phenomenon,which makes the traditional Maximum Power Point Tracking(MPPT)control algorithm ineffective.Therefore,it is of practical significance to study MPPT technique under partial shading.For the study of photovoltaic maximum power point tracking technology,first of all,this paper introduces the working principle of the photovoltaic cells,study the different mathematical model,the simulation analysis of the output characteristics of battery,and expounds in detail the pv array under partial shade multimodal phenomenon and the mechanism of the simulation under the shade of the output characteristic curve are analyzed.Then,the conventional MPPT technology is studied theoretically,and the advantages and disadvantages of each algorithm and the applicable occasions are compared through simulation.Under the condition of partial shade,this paper introduce particle swarm optimization algorithm,and its important parameters was improved,for different particle selection,this paper based on the voltage and the duty ratio of two types of particles,the feasibility of the algorithm is validated by MATLAB/Simulink simulation platform and a good optimization performance,and compared with the traditional perturbation method,verified the possible failure of conventional algorithm under the condition of multimodal problems.Finally,the MPPT controller is designed with DSP28335 as the core,and its hardware circuit includes DC/DC circuit,sampling circuit,power circuit and drive circuit.The system software includes main program,AD sampling interrupt program and PWM output program.Through setting up photovoltaic system control experiment platform,to verify the improved particle swarm algorithm based on duty ratio under uniform illumination and partial shade environment performance,and compared with the perturbation method,shows that this algorithm can effectively solve the problem of multi-peak maximum power tracking and the steady-state oscillation is better than traditional algorithm,in the actual application plays an outstanding role in improving the efficiency of photovoltaic power generation.