Research On Charge Converter Of Low Power Photovoltaic Electric Vehicle

In the past decade,solar photovoltaic power generation has become one of the main ways of solar energy utilization.The energy obtained by using photovoltaic power generation technology is a kind of renewable energy with relatively wide distribution?clean environmental protection and great energy.Charging electric vehicles through photovoltaic power generation technology not only reduces environmental pollution but also improves the utilization rate of solar energy.This thesis designs a small power photovoltaic electric vehicle charging converter to charge electric vehicle battery.Firstly,the equivalent circuit diagram of photovoltaic cells was analyzed,and the mathematical model of photovoltaic cells was built by MATLAB.The parameters of photovoltaic modules were substituted into the command windows of MATLAB,and the I-V characteristic curve and P-V characteristic curve of photovoltaic cells were obtained after input of corresponding programs.As the output voltage and current of photovoltaic cells are affected by external temperature and light intensity,the I-V characteristic curve and P-V characteristic curve of photovoltaic cells with the same temperature and different light intensity and the same intensity and different temperature are compared and analyzed in MATLAB.Secondly,the maximum power point tracking of photovoltaic cells is analyzed.In order to improve the charging efficiency of photovoltaic cells on electric vehicle batteries,it is necessary to ensure that photovoltaic cells always maintain the maximum power output.This thesis adopt a MPPT composite control strategy combining variable step size perturbation observation method and Lagrange interpolation method.MATLABsimulation proves that the method solves the problem that the traditional perturbation observation method cannot take into account both steady state accuracy and tracking speed,and proves the feasibility of the method.Then in MATLAB based on the PID closed-loop control MPPT simulation model of the Boost circuit,acquisition of photovoltaic cells,the output voltage and current output disturbance after Lagrange MPPT control module step length,step length signal after triangle chopper output PWM signals,by adjusting the duty ratio of switch tube to change the value of the output voltage,finally according to the output power of the photovoltaic cells to judge whether the current working point is located in the maximum power point.Finally,an experimental prototype of a low-power photovoltaic EV charging converter is built,and the EV battery is charged to verify whether it meets the specified requirements.