The Research Of Tractor Power Management System Based On Single-chip Microcomputer Monitoring

Tractors play an important role in agricultural mechanisation as an important power machine in agricultural machinery.The tractor requires a large amount of battery power to start,and when the battery power is low,it can cause the tractor to not start properly.When the tractor is not started,the generator does not generate electricity,use the tractor power for night lighting and other power-consuming purposes,the battery will always be in a discharged state,and nowadays the agricultural machinery will mount many electric drive devices,the generator power supply is insufficient,the battery occurs over-discharge phenomenon,resulting in its remaining power can not meet the tractor normal start.Therefore the study of tractor power management system is of great significance.This paper designs a tractor power supply monitoring and management system.The main research content is as follows:(1)Design the battery SOC estimation algorithm.As the battery is a non-linear system and there are many factors affecting it,the extended Kalman filter is used to linearise the non-linear battery system and then the standard Kalman filter is used for estimation.In order to make the estimated values accurate,the equivalent current coefficient and temperature coefficient are introduced in the composite model of the battery for correction.(2)Tractor power monitoring and management system design.Complete the hardware circuit design and software design of the tractor power management system based on STM32F103C8T6 monitoring,and make the physical object.The system can realize the generator output voltage control between 12.8V-13.8V,and real-time monitoring of the battery voltage,current and temperature,and the battery SOC estimation.(3)Tractor power monitoring and management system performance verification test.The waveform of the generator voltage controlled by the microcontroller was measured by an oscilloscope and an automotive universal test bench,and the waveform of the generator output voltage controlled by the voltage regulator was compared with the waveform obtained by Simulink simulation,and through the analysis of the comparison results,it was found that the microcontroller can replace the voltage regulator to achieve the function of controlling the generator output voltage,thus proving that the performance of the tractor power monitoring and management system meets the design requirements.(4)The microcontroller monitoring battery parameters and algorithm to estimate the battery SOC test and results analysis.This paper took three different batteries to the tractor for starting test,the microcontroller measured the battery voltage,current,temperature and the estimated battery SOC and the actual test using intelligent battery tester data results for comparison and analysis,the algorithm to estimate the battery SOC accuracy to meet the actual requirements.Through the above study,the final conclusion is that when the battery voltage drops to 7.21 V and the battery SOC is around 30%,the tractor can still complete three normal starts,the battery is in the overdischarge state.