| With the global shortage of fossil energy and environmental pollution becoming more and more prominent,new energy generation with clean and renewable characteristics has become the direction of future development.Among them,photovoltaic power generation has huge advantages such as low pollution,low noise and low operating cost,so its development and utilization are widely valued by various countries.However,solar photovoltaic power generation systems reveal many shortcomings in the process of use.First of all,the actual effect of photovoltaic conversion rate is poor,on the other hand,the photovoltaic system itself is unstable and has the characteristics of randomness and variability,which causes great damage to the safety and reliability of the power system.In order to solve the above shortcomings,this paper conducts an in-depth study on two aspects: the control strategy of overall maximum power tracking of solar PV arrays and the energy management strategy of hybrid energy storage.However,there are still many shortcomings in the practical application of photovoltaic power generation system.First,the low conversion rate of photovoltaic power generation needs to be improved.Secondly,the randomness,volatility and intermittency of photovoltaic power generation pose a serious threat to the safe and stable operation of power grid.In view of the above two problems,the control strategy of global maximum power tracking of photovoltaic arrays and hybrid energy storage management strategy are studied in this paper.(1)The basic components of PV power generation systems and their principles and characteristics,as well as the principles of hybrid energy storage systems,are analyzed.A PV array simulation model is established in Matlab to simulate and analyze the power generation of PV arrays in partial shading,and the results show that the existence of multiple local maximum power points when the PV array is in partial shading has an impact on the traditional PV maximum power tracking strategy.(2)To address the problem that the traditional maximum power point control strategy(Maximum Power Point Tracking,MPPT)cannot achieve a good tracking effect under the changing illumination environment,the cuckoo algorithm is used for maximum power tracking.The cuckoo algorithm firstly generates new values by iterating through the Lévy flight equation,which makes it have the feature of good global search effect.Secondly,to address the problem that the cuckoo algorithm converges to the optimal solution too slowly,the cuckoo search algorithm is switched to the conductance increment method to converge to the optimal point quickly when it finds the optimal point.Finally,comparing the convergence times of the cuckoo algorithm and particle swarm optimization algorithm for the same convergence function before and after the improvement,the improved cuckoo algorithm is verified to have good convergence after arithmetic experiments.And the simulation is built in Matlab/Simulink to study the convergence time and tracking efficiency for constant and changing illumination conditions.The results show that the improved algorithm can track the maximum power in a complex environment,with a better search effect and fast response speed.(3)In order to suppress the fluctuation of PV output power,this paper introduces a hybrid device and proposes an optimal allocation rule for energy storage power based on battery SOC feedback regulation to solve the drawback that energy storage elements are prone to overcharge and overdischarge,which constitutes a two-stage power command allocation method for scientific power distribution through two seriesconnected low-pass filters for first-level allocation and secondary correction based on energy storage SOC fuzzy control.The power is allocated scientifically by a two-stage power command allocation method based on two series low-pass filters and a secondary correction based on energy storage SOC fuzzy control.Finally,the simulation verifies that adding this control strategy can smooth out the PV power fluctuation,and the power fluctuation range of 1min scale and 10 min scale are within the national standard.Meanwhile,it can be known from the power allocation and SOC of each energy storage element and the SOC state of supercapacitor under extreme conditions that the control strategy can make the energy storage device give full play to its own function and at the same time can be fully protected to ensure that the charge state of the energy storage element works in the normal range,which effectively improves the performance of the photovoltaic storage system. |
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