High-power Lead-acid Battery Charging Control System For Mining

With coal being an important source of energy which occupies a major position in the national economy,more and more attention has been paid to the intelligence of coal mine production.Mining electric locomotive,an important electromechanical equipment in coal transportation,is typically powered by lead-acid batteries,the working efficiency,service life and operation reliability of which are highly dependent on the performance of their charger.Given the facts that the chargers widely used in coal mine sites are mostly old and low automated equipments utilising simple control method,costing long charging time,cosuming high energy,and requiring artificial attendant,it is difficult to follow the battery charging characteristics when charging,and so might easily damage the batteries or shorten their service life.Therefore,the paper designs a charging control system for the mining high-power lead-acid battery based on variable universe fuzzy PID control.The main content of the paper is as follows:First,the paper analyzes the working principle of the main circuit and control circuit of the mine charger,and use MATLAB to simulate the three-phase fullycontrolled rectifier circuit.Based on this,the overall design of the charging control system is proposed.Aiming at the problem of the single charging strategy of the charger,based on the acceptable current curve of the battery,a multi-stage charging method of constant current charging-constant current pulse charging-constant voltage chargingfloating charging is designed.Considering that the charger using analog electronic circuits to control the charging voltage and current would cause relatively large error,the variable universe fuzzy PID control is innovatively applied to the lead-acid battery charging process.The paper also established a simulation model of variable universe fuzzy PID and charging system.The results show that variable universe fuzzy PID control is better than conventional PID and fuzzy PID control in terms of error accuracy,response speed and steady-state effect.Secondly,the software and hardware design was completed according to the charging control requirements.Based on the STM32 chip,the hardware circuit designs thyristor trigger,charging voltage and current collection isolation circuit and other circuits.And in terms of software,modules such as charging subroutines,AD conversion,and digital filtering are designed to realize the software programming of the control algorithm.The system is also designed with storage,communication and man-machine interface functions to facilitate the modification of related parameters such as charging.Finally,after completing the debugging and simulation test in the laboratory,the test was carried out on the coal mine site.The charging control system completed the55-cell lead-acid power battery charging experiment.And the results show that the charging process is stable and effective,and the charging voltage and current are stable;the charging time is shortened from the original 12 hours to 8 hours,which reduces the energy consumption of charging;each stage of charging realizes automatic switching without manual duty,and the charging power is automatically cut off after the end of charging,which greatly improves the safety of the battery during charging;The developed charging control system conforms to the lead-acid battery charging law during charging.Totally speaking,through real-time detection of charging voltage and current,the system can perform effective closed-loop control of charging voltage/current under the action of control strategies and algorithms,realizing fast and efficient charging of lead-acid power batteries for mining.The designed humanmachine interface and related charging modules are convenient for modifying related charging parameters,so that they can be used to charge lead-acid battery packs of different models and voltages.The charging system developed has improved the intelligent level of mining lead-acid power battery charging,which can be used to upgrade and transform old chargers and thus has a wide range of application prospects.