Research Of MPPT Algorithm Based On PSO And Variable Step P&O In Photovoltaic Power Generation System

As a result of fossil energy depletion and severe weather,represented by fog haze and global warming,frequent occurrence,new energy power generation is more and more got the favour by all countries in the world.Nowadays,as a main force of new energy power generation,installed capacity of the photovoltaic power generation has reached 77.42 GW in our country and it is at the top of the world.However,in the photovoltaic power generation systems,the output power of photovoltaic array is strongly influenced by ambient temperature and light intensity,Such as PV array is often partially shaded by clouds,and power-voltage curve is not stable.Therefore,research on MPPT algorithm in the photovoltaic power generation system is the key to improve the efficiency of photovoltaic power generation.Considering the situation that environmental change and local shadow shaded PV array impacted power-voltage curve,it is put forward a new algorithm and verify reliability and superiority of the algorithm by the simulation and experiment.Focused on the nonlinear PV array,it proposes a maximum power point tracking algorithm,namely PSO fusion variable step P&O algorithm,which is fast,stable and able to globally optimize.The algorithm uses improved particle swarm optimization algorithm to update the velocity and position of all particles under a certain number of iterations,making output power close to the location of maximum power point;And then,the traditional variable step P&O is improved in second stage,it uses the method of variable step P&O whose step length is decided by sequence of Fibonacci number,so that it gets good connection with first-stage algorithm,thus power of the optimal solution is obtained.Finally,it designs iterative termination conditions after every stage algorithm,and set the condition of restart in the last.Aiming at the compound control algorithm,it build a simulation model in the MATLAB/Simulink,and simulate the two situations that shadow static shading and shadow dynamic shading,and respectively map P-t and D-t curve of the MPPT algorithm compared with the traditional PSO algorithm and varied step P&O algorithm.It is verified that it is improved significantly on the accuracy and speed.In addition,it has set up a simulation interface for the compound control algorithm in the LabVIEW.Therefore it shows graphical programming and process of the algorithm,and finally it concludes that the algorithm of tracking data and tracking effect.In order to verify that performance of the compound control algorithm in the actual photovoltaic power generation systems,it designs a MPPTexperiment platform in photovoltaic power generation system,and configures the Boost circuit's parameters,and designs the control circuit which as the core of the DSP2812 and sets the peripheral hardware circuit,such as the sampling circuit,protect circuit,drive circuit.Besides,in the PC,it completes the main program and sampling program and the like in the CCS3.3.Finally,compared two traditional algorithms,after many repeated experiment,it proved that the the algorithm is excellent on many aspects,such as the number of successfully optimization,maximum power point and time of arrival on maximum power.To sum up,it verifies the algorithm has feasibility and advancement.In conclusion,both the results of simulation and experiment show that PSO fusion variable step P&O algorithm solves the problem that P-U curve has more extreme under the condition of complex illumination.The algorithm not only has a good dynamic performance and the fast tracking velocity,and it is stable,effective.So it improves the conversion efficiency of photovoltaic array,and is of great significance for the development of photovoltaic power generation system.