Design Of High-speed Permanent Magnet Synchronous Motorized Spindle Motor And Research On The Matching Characteristics For The Electromechanical Coupling System

Permanent magnet(PM)synchronous motorized spindles(PMSMS)have a wide range of applications in high-speed/ultra-high-speed precision grinding due to their heatless rotor in principle,high efficiency,high power density,low inertia,fast dynamic response and hard torque characteristics.However,due to the complex coupling of the electromechanical parameters of the "drive-motor-spindle-cutter-load" system of high-speed permanent magnet synchronous motorized spindles(HSPMSMS),improper matching of system parameters will cause fluctuations in the output torque and speed of the spindle,resulting in a decline in the stability of the system and the quality of processing.The current problems regarding the electromechanical coupling of high-speed motorized spindle systems have been better solved in the field of asynchronous motorized spindles,but have not yet involved PMSMS,which need to be studied and solved urgently.The research work in this paper is as follows:(1)The electromagnetic theory design of the 8kW/80 krpm high-speed permanent magnet synchronous electric spindle motor is carried out.A 2D electromagnetic field finite element analysis model of a HSPMSMS motor is established based on ANSYS EM.The influence of electromagnetic design parameters such as air gap length and stator slot width on the steadystate performance of the motor is investigated,and the reasonable parameters selection range are determined.(2)The electromechanical coupling dynamics model of the "inverter-motor-spindlegrinding wheel-grinding load" system of a HSPMSMS is established based on the working principle of drive frequency modulation,motor dynamics and Lagrange analysis dynamics theory.According to the characteristics of the model,Runge-Kutta method is adopted to realize the quantitative simulation of the transition process of the high-speed grinding PMSMS system.(3)The effects of motor parameters,inverter parameters and grinding load on the current,electromagnetic torque and speed of the motorized spindle and grinding wheel torsional vibration are investigated using the established electromechanical coupling model and the proposed model solution method.The strategies to suppress the system electromechanical coupling vibration are proposed.The study shows that,within the given parameters,increasing the air gap length,reducing the stator slot width and increasing the carrier frequency can effectively reduce the grinding wheel torsional vibration and suppress the system electromechanical coupling vibration.(4)The prototype 8kW/80 krpm motorized spindle is produced and the experimental bench is built.The voltage and vibration of the motorized spindle at no load are measured and compared with the simulation results.The error of the voltage value do not exceed 10.35%,and the vibration trend is basically consistent with the simulation results.The experimental results show that the prototype can run within 75 krpm,and increasing the carrier frequency can effectively suppress the vibration of the motorized spindle.The experimental results are consistent with the simulation analysis results.The research provides important theoretical methods and effective approaches for the development and design of high speed/ultra-high speed PMSMS motors and the optimal matching of system parameters.At the same time,it provides an engineering development case of 8kW/80 krpm HSPMSMS.