Research Of Digital Control Power Optimizer Based On Four Switch Buck-Boost

In the context of current global energy depletion,the deterioration of the ecological environment,and the greenhouse effect,photovoltaic energy generation is highly valued by contries around the world and has achieved rapid development.The optimization of photovoltaic array structure and the selection and control of power optimization topology are the key factors to solve the problems of inadequate utilization of photovoltaic array energy and low system efficiency.This paper has carried out in-depth disscation and research on the array structure and DC/DC optimizer of small-scale stand-alone photovoltaic power generaton system.Based on the research status and existing problems of photovoltaic system,this paper focuses on the photovoltaic array power generation efficiency and optimization strategy,with in-depth analysis of key issues of power optimizer based on Four Switch Buck-Boost converter.First,a brief introduction to the common power optimizaion structure is carried out,and the advantages and disadvangages are analyzed for their respective structural and energy transmission characteristics.The operating principles of the parallel distributed power optimization structure is analyzed in detail.Four Switch Buck-Boost converter is employed as power-optimized DC/DC topology according to the input and output characteristics of the structure.A DSP-based digital control method is daopted thanks to its flexibility,strong anti-interference and low costs.The Four Switch Buck-Boost converter has single and dual duty circle mode in terms of control mode,and has single-loop and double-loop control in terms of control loop.Then,a single-loop dual duty circle control strategy is applied by analyzing the respective advantages and disadvantages.On the basis of this control mathod,the system's smooth transition,loop control,digital PID compensator design and other issus are investigated in this paper.In addition,the average small-signal model about input control in different opreating modes is deduced and a piece-wise compensator is designed based on the original transfer function to improve system dynamic performance.Finally,the digital-control-based hardware architecture is expounded in the last chapter,which focuses on the critical circuit hardware design and builts a 660W experimental platform for photovoltaic power generation system.The maximum power point traching algorithm is tested and its correponding waveforms are analyzed.Theoretical results are verified by the experimental waveforms and data on this platform.