Research On Maximum Power Point Tracking And Multi-inverter Group Control For Photovoltaic Generation Under Partial Shading Conditions

As an important way of solar energy utilization,photovoltaic generation has developed rapidly.However,weather changes,partial shading and the inverter performance all have an impact on the efficiency of photovoltaic generation,making it less efficient.In order to reduce the influence of partial shading on photovoltaic generation and improve the efficiency of power generation,this paper firstly research the maximum power point tracking(MPPT)of photovoltaic arrays under partial shading conditions to obtain the maximum power.Then the low conversion efficiency problem of grid-connected inverters has been researched when the photovoltaic arrays output power decreases.The main research contents of this paper are as follows:1)The mathematical model of photovoltaic arrays under partial shading conditions is established,and the multi-peak characteristics of output power of photovoltaic arrays arc analyzed.Aiming at the tracking failure of traditional maximum power point tracking(MPPT)methods under multi-peak conditions,an intelligent MPPT tracking method based on improved grey wolf optimization algorithm is proposed.Simulation results show that the proposed method can accurately track the maximum power point under uniform irradiance and different partial shading conditions.And compared with the original grey wolf optimization algorithm and particle swarm optimization algorithm,the performance of power tracking has been significantly improved.2)When the photovoltaic array is under weak illumination conditions,the output power is often far less than the rated power of inverters,which makes the power conversion efficiency of the inverters greatly reduced.In order to improve the overall power conversion efficiency of photovoltaic generation,this paper proposes to replace a high-power inverter with several low-power inverters in parallel by group control of multi-inverter.To begin with,different photovoltaic grid-connected topologies and multi-inverter group control strategies are discussed,and an improved multi-inverter equivalent power operation group control strategy is proposed.Then,using the power generation data of a photovoltaic power plant with a capacity of 30kW for half a year,the proposed method was simulated and analyzed.Finally,the proposed strategy was carried out on a photovoltaic generation experimental platform with a capacity of 15 kW.The results show that the proposed group control strategy can greatly increase the power generation efficiency of photovoltaic plants.