Research On Battery Charging Technology In Photovoltaic System Based On MPPT

With the development of photovoltaic technology,solar energy conversion efficiency enhances unceasingly.Photovoltaic power can be used without geographical restrictions,making it an important way to use solar energy.The lead-acid batteries used in energy storage systems are used as traditional energy storage methods with high conversion efficiency,but these batteries are not designed specifically for photovoltaic systems.The battery conditions are difficult to adapt to the volatility and unpredictability of photovoltaic power generation,which leads to the service life and efficiency of the battery are seriously reduced,especially the cost of the battery in the independent photovoltaic system is large.Therefore,research on the maximum power point tracking control technology(MPPT)and battery charge and discharge technology of photovoltaic systems is extremely important to improve system operation efficiency and reduce costs.Firstly,the paper analyzes the multi-peak characteristics of photovoltaic power generation and the charging characteristics of lead-acid batteries in independent photovoltaic power generation system,and discusses the problems of undercharge,overcharge and polarization that the battery faces issues when the output characteristics of photovoltaic cells are combined with batteries.Based on Mas' s optimal charging theory,this paper combines the maximum power tracking technology with the threestage battery charging method to ensure the maximum efficiency of solar energy utilization.This paper proposes a three-stage battery charging method based on MPPT algorithm.At the same time,the traditional MPPT algorithm fails the maximum power tracking under local shading,which leads to the reduction of energy utilization.In this paper,an intelligent MPPT algorithm combining the improved ant colony algorithm and the admittance incremental algorithm is designed to maintain the maximum energy to charge the battery to avoid undercharging even when the photocell has multi-peak output,thus prolonging the service life of the battery.In Labview virtual simulation platform for the design of algorithm simulation,the simulation results show that the designed algorithm has good dynamic tracking ability and tracking effect.Secondly,the hardware circuit and software program design are carried for the photovoltaic battery charging system experimental platform.The whole control circuit adopts BUCK circuit as the topology structure,and the core device selects TMS320F2812 DSP digital processor to design and weld peripheral circuits such as battery discharge circuit,signal acquisition circuit and drive circuit.Software program design On the CCS3.3 development platform,each part of the subroutine is modularly compiled and debugged.In the main program,the subroutine is called according to the requirements through the interrupt program to complete the required control functions.Finally,the hardware circuit component parameters are continuously tested,adjusted,and debugged and run on the software system.The software system and the hardware platform are combined to complete the battery charging and discharging experiment of the photovoltaic system,and the experimental data is obtained and statistically analyzed,and the charging quality and charging effect are analyzed.The experimental results show that the independent photovoltaic system operates reliably.The designed charging control strategy realizes the intelligent switching of the charging mode during the charging process.The charging efficiency exceeds 96.1%.The actual engineering application effect also reflects the superiority of this strategy and meets the design requirements.