Research On Photovoltaic System MPPT And Inverter Harmonic Suppression Strategy Based On Improved Wolf Pack Algorithm

With the continuous increase of photovoltaic installed capacity and the current mainstream trend of photovoltaic grid-connected,research on the tracking of the maximum power point of photovoltaic array output and the harmonic suppression of photovoltaic inverters have attracted more and more attention.When the PV array is partially occluded,the output characteristics show multiple peaks.The traditional MPPT strategy will no longer be applicable.When the PV is connected to the grid,the inverter will generate harmonics to affect the power quality.SHEPWM has simple control and can select harmonics.Elimination and other advantages,but the need to solve more complex nonlinear equations,it is more difficult.Based on the wolf group algorithm,it has better global optimization ability.In this paper,the improved wolf pack algorithm is applied to the maximum power point tracking and inverter SHEPWM technology of photovoltaic system,and the simulation is verified.The photovoltaic cell simulation model is built and the output characteristics of the model are simulated and analyzed to verify the correctness of the model.The causes and solutions of the hot spot effect are studied.The intrinsic reason of the P-U curve multipeak output of the array is analyzed.To overcome the drawbacks of traditional wolf pack algorithm,such as fixed walking direction,unable to regulate walking distance dynamically,lack of information exchange between artificial wolf and head wolf not participating in intelligent behavior,a improved wolf pack algorithm was proposed.This algorithm provided probing wolf a walking behavior which could change direction and vary steps size based on the Fibonacci sequence.In addition,it added the information exchange between the wolf and the probing wolf during the fierce wolf raid.Meanwhile,it enhanced the hunting principle of wolf hunting and improved the globality,convergence speed,convergence accuracy,and robustness.The simulation results showed that compared with wolf pack algorithm,the improved wolf pack algorithm,this not only improved the global search ability of the algorithm,but also avoided early-maturing of the algorithm.Furthermore,it had a strong robustness and great improvements in the search accuracy and convergence speed.The photovoltaic system MPPT simulation model was built,and the PV arrays with different occlusion conditions were packaged and studied,and their output characteristics were studied.Under the static occlusion condition,the simulation analysis was carried out on the five package models to verify that IWPA tracked at the maximum power point compared with WPA and P&O.The superiority is set;The simulation results show that IWPA achieves the effectiveness of maximum power point tracking under local occlusion conditions.The SHEPWM nonlinear equations for eliminating 5th,7th,11th and 13th harmonics are established.The simulation of unipolar modulation and bipolar modulation based on the improved wolf group algorithm is performed.The IWPA is optimized for the SHEPWM technology.The validity of the simulation is compared with the genetic algorithm simulation.The simulation results show that the IWPA is superior to the genetic algorithm in solving the SHEPWM switching angle.