Research On Power Control Of Photovoltaic Charging Station For Electric Vehicles

The development of electric vehicle has alleviated the problems of energy crisis and global warming,the construction of Photovoltaic electric vehicle’s charging station provides enough energy.However,there are still some problems which will cause the waste of energy and decay of battery life existed in photoelectric cell charging station,such as the inefficiency of the energy conversion of photovoltaic batteries,the poor management of accumulator charging.Therefore this research will give a detailed analysis on how to promote the conversion efficiency of photoelectric cell and improve the charge management of power accumulator battery of electric vehicle.This research aims at finding the way to promote the conversion efficiency of photoelectric cell and improve the charging management of power accumulator battery of electric vehicle.And the software of Simulink is utilized to build the simulation models of photoelectric cell and power accumulator battery,so that the maximum power point tracking strategy of photoelectric cell and the control strategy of power accumulator battery could be applied.Meanwhile,the construction of system hardware platform could be completed to identify the feasibility of this strategy.Firstly,the MPPT strategy of photoelectric cell has been improved in photovoltaic electric vehicle charging station,including analyzing the equivalent circuit of photoelectric cell,making mathematical model based on equivalent models and building Simulink Simulation model.Then different ambient temperature and light intensity are set to identify the output characteristics of photoelectric cell.What’s more,some improvements will be made in the traditional tracking method to make a higher output efficiency of photoelectric cell by segmenting △P、△U、△I.And different step-sizes are set based on different segmentation,which can be called the method of incremental conductance.Secondly,this research will give a detailed analysis on the control strategy of power accumulator battery.The equivalent circuit of accumulator battery will be analyzed to work out its mathematical model.And the disadvantages of traditional accumulator charging will also be analyzed,then some improvements will be made in traditional multi-stage charging.The energy conversion of photoelectric cell will be taken into account so that the MPPT process of photoelectric cell could be integrated with traditional multi-stage charging,which could be divided into four procedures,trickling charge,MPPT bulk charge,constant-voltage charge and floating charge.Furthermore,the four charge procedures will be combined with the equalizing charge of power accumulator battery of electric cars to form a new photovoltaic equalizing charge method,which could alleviate the problems of inefficient charge and energy conversion and discrepant initial capacity of different power accumulator battery.Then a Simulink simulation model will be built to check the feasibility of this strategy.The last part introduces the software and hardware design and results of the control strategy of photovoltaic equalizing charging.Hardware design consists of the design of the main charging circuit and the detection circuit and the balance of module circuit.And software design is composed of some main control strategies,including MPPT control strategy,four-stage control strategy and equalizing control of charging.Then the establishment of hardware platform of photovoltaic equalizing charging system could verify the feasibility of the control strategy of photovoltaic equalizing charging and effects of system hardware.