Research On MPPT Control Strategy Of Photovoltaic Power Generation System Under Partial Shadow

With the development of social progress,human demand for energy is increasing day by day.Under the double pressure of environmental crisis and energy shortage,people are striving to develop new types of renewable energy.Solar energy,as one of the many renewable energy sources,has attracted wide attention because of its unique advantages such as abundant reserves,pollution-free and not subject to geographical restrictions.Solar photovoltaic power generation is considered to be the most promising new energy technology.In order to enhance the efficiency of photovoltaic power generation and ensure the maximum power output of photovoltaic power generation system,maximum power point tracking(MPPT)control has become a hot research topic in recent years.When partially shaded,the output power-voltage(P-V)characteristic curve of photovoltaic arrays presents multi-peak characteristics.The traditional MPPT method is easy to fall into a local maximum power point,and cannot track the global maximum power point quickly and accurately,which leads to the decrease of the power generation efficiency of photovoltaic grid-connected system.The MPPT method based on artificial intelligence algorithm not only has fast convergence speed,but also has high search accuracy.It is a hotspot in MPPT application research at present.Artificial Bee Colony(ABC)algorithm,as an intelligent random search algorithm,has few control parameters,easy implementation and excellent anti-disturbance performance.But there are also some problems in practical application,such as unbalanced convergence speed and accuracy,and small scope of application.Therefore,this paper analyses the electrical characteristics of photovoltaic arrays under partial shadows.By adding an adaptive search operator,an adaptive honey source search equation is proposed,which improves the disadvantage of unbalanced exploitation and development ability of basic ABC algorithm in global optimization.Based on this,this paper proposes a maximum power point tracking strategy based on modified artificial bee colony algorithm to achieve power control under multi-peak conditions,find out the global maximum power point of photovoltaic system under partial shadows,and adjust the maximum power output in real time.A single-phase photovoltaic inverter is designed to realize grid-connected control,which ensures the stable and reliable operation of the grid-connected system.Finally,according to the proposed global MPPT strategy and the designed grid-connected controller,the simulation of single-phase photovoltaic grid-connected power generation system under partial shadows is carried out in Matlab/Simulink.The simulation results show that the proposed MPPT control strategy of photovoltaic power generation system based on modified ABC algorithm can track the maximum power point under partial shadows,improve the power generation efficiency of photovoltaic system,and the designed single-phase inverter can be successfully connected to the grid.The feasibility and effectiveness of the proposed control strategy are verified.