A Decentralized Control Strategy for Single-Phase Cascaded Photovoltaic Inverters
Cascaded inverters can improve efficiency and save costs,so they are increasingly used in photovoltaic grid-connected power generation systems.In order to realize the series connection of inverters with different power generation capabilities or capacities,and to enable each unit to independently complete the maximum power point tracking,this paper proposes a decentralized control strategy for single-phase cascaded photovoltaic inverters that can realize MPPT.By improving the traditional droop control expression,the actual power output by each photovoltaic unit is tracked to the maximum power point power,and the voltage amplitude is proportional to the maximum active power,so that the output voltage frequency and phase of each unit are self-synchronized without the need for Communica-tion,the output voltage amplitude is adjustable and proportional to its actual power capacity.Finally,based on the Matlab/Simulink platform,a simulation model of cascaded grid connection of three photovoltaic units is built,and the results verify the feasibilityand effectiveness of the proposed method.
Cascaded H-bridgeDistributed controlMPPTPower balance controlPhotovoltaic grid-connected system
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