Research And Design Of Battery Management System For Mining Electric Locomotive

As the main auxiliary transportation equipment of coal production,the mine electric locomotives bears the transportation task of personnel and equipment,and its operation performance affect the production capacity and economic benefit of coal mines.The power source of battery-type electric locomotive is provided by battery pack.Lead-acid battery has the advantages of high safety,mature technology and low cost,and in battery motor vehicle it is common to use it as power unit,but there are some problems in the use of lead-acid battery,such as short cycle life and low charging efficiency.Therefore,in the process of motor vehicle operation,it is necessary to introduce battery management technology to overcome the shortage of the battery itself,which is of great significance for improving the safety and economic benefits of the motor vehicle operation.The paper takes the battery pack of battery motor vehicle as the research object.Firstly,It analyzed the working mechanism of battery and the power demand of mining motor vehicle operating conditions.On this basis,a new battery pack charging structure and charging and discharging control strategy are designed.The charging process of battery pack is divided into series constant current stage and parallel constant voltage stage.According to the charge quantity of monomer battery,charging the charging structure of battery pack through the switching device,the self-equalization of energy can be realized in the charging process of monomer battery.And the influence of battery temperature is considered in the SOC estimation method.The SOC value of battery pack is estimated by combining the advantages of Ann-Time-Integral method and open-circuit-voltage method.Considering the influence of battery charge and discharge current on the battery,the paper uses double-sided DC-DC power conversion circuit to control the charge and discharge of the battery.And designed the battery charging and discharging controller based on PI control,during the battery charging process the current closed-loop control realizes the battery constant current charging.The voltage outer loop and current inner loop double closed-loop control realizes the battery constant voltage charging;and in the process of battery discharge,the double closed-loop is used to realize the stable discharge voltage of the battery pack and limit the discharge current.The simulation model of different charging modes of battery pack is established,and the simulation results verify the correctness and feasibility of the battery pack structure and control strategy.Finally,the design of the battery management system test platform was completed,including hardware circuit design and software design.And battery monomer voltage test,current test,charge equalization test and battery pack discharge test were carried out.The test results show that the designed battery management system of the mine electric vehicle can make the battery have better balance during the charging process;in the battery discharging process,it can effectively alleviate the discharge current of the battery.