Research On The Key Technologies Of Gearless Mill Drive

Gearless mill is the product of today's development trend of large-scale and energy-saving mining equipment,which has the advantages of high power,high efficiency,low energy consumption and high reliability.Supported by the Natural Science Foundation of China(Grant No.51775225),the key technologies of gearless mill drive are studied,and the structure and electromagnetic design of the motor for drive are carried out.The vector control system of gearless mill drive is built,and its speed regulation performance and anti-load disturbance capability are analyzed.The electromechanical coupling model of gearless mill is established,and the simulation results are verified theoretically.Firstly,the current status of domestic and international research on gearless drive technology,AC motor vector control and electromechanical coupling problems is reviewed.Comparing the characteristics of different drive motors,permanent magnet synchronous motor is selected as the motor for gearless mill drive,and the preliminary design of its rotor structure,stator structure and stator winding is carried out with the structural composition of gearless mill drive.The motion state of the medium under the working condition of the mill is systematically analyzed,and the theoretical calculation method of the working parameters of the mill is derived to provide the theoretical basis for the simulation analysis in this paper.The two-dimensional electromagnetic field finite element model of the permanent magnet synchronous motor for gearless mill drive is established by combining the basic principles of two-dimensional electromagnetic field and finite element method.By analyzing the mechanism of motor tooth slot torque generation,the pole arc coefficient and magnet eccentricity distance are selected as parameters for optimization.It is shown that the optimized permanent magnet pole structure has a significant weakening effect on the motor slot torque,which can effectively improve the vibration and noise problems caused by it.Based on this,the no-load performance parameters and load running characteristics of the motor are analyzed in Maxwell 2D,which proves the rationality of the design of permanent magnet synchronous motor for gearless mill drive.The state equations and mathematical model of the permanent magnet synchronous motor for gearless mill drive are derived and established,the vector control principle and SVPWM algorithm of the permanent magnet synchronous motor are introduced systematically,and the vector control system for gearless mill drive is built in MATLAB/Simulink,and the simulation analysis of the speed and load abrupt change conditions is completed.The results show that the speed regulation performance and load disturbance resistance of the gearless mill drive system based on the id=0 vector control strategy are good,and it can cope with the speed demand and the influence of dynamic feeding and discharging on the drive system under different working conditions of the mill.In order to obtain the performance of the gearless mill drive under conditions closer to the actual operation,a discrete element-dynamics virtual prototype model of the gearless mill cylinder is established using the multi-body dynamics software RecurDyn,and the construction of the RecurDyn-Simulink simulation model of the electromechanical coupling of the gearless mill drive is completed through the interface between the software.From the simulation results of the mill start-up process,the media motion state and drive system performance are analyzed.The simulation results are compared with the theoretical calculation values to verify the correctness of the electromechanical coupling simulation model.In this paper,a two-dimensional electromagnetic finite element model of a permanent magnet synchronous motor for gearless mill drive is established,and the motor cogging torque is effectively weakened by optimizing the permanent magnet parameters.A vector control system for gearless mill drive is designed and an electromechanical coupling simulation model is built.The research method of the paper can provide a reference for the research of key technologies of gearless mill drive.