Research On Temperature Rise And Vibration Of Switched Reluctance Motor For Crane Based On Magneto Thermal Bidirectional Coupling

Switched reluctance motor is a electromechanical integration of special motor speed regulation,with high efficiency,large output torque,solid structure,wide speed range and many other advantages.Induction motor is usually used as the power source of traditional cranes.This type of motor has the disadvantages of large current at the starting time and low efficiency in the low speed range,and it is difficult to meet the needs of high efficiency and high reliability of modern motor.Therefore,the introduction of switched reluctance motor into the field of crane industry is of great significance for the upgrading of the cranes.In order to improve the efficiency and reliability of cranes motor,this dissertation design a 18.5k W switched reluctance motor for cranes.In consideration of multiple physical fields,the basic structural parameters of the motor are designed based on traditional design theory and operation principle.Using time stepping finite element method,a two-dimensional electromagnetic field calculation model is established to analyze and calculate the static characteristics and transient magnetic field distribution of the motor.A three-dimensional fluid structure coupling global model considering the rotation of the rotor and fan is established.Based on the fluid structure coupling method,the flow velocity in the surrounding air region caused by the operation of the motor is numerically calculated.Combined with the actual application,the variation rules of core loss and winding loss under different load conditions are analyzed.In view of the high temperature rise phenomenon of heavy load operation of switched reluctance motor,a new structure of rotor end ring equipped with cooling fins is proposed.Considering the influence of the working temperature on the core and winding materials,a magneto thermal bidirectional coupling analysis method is proposed to calculate the global temperature field of switched reluctance motor.The influence of winding temperature rise on phase inductance and phase current is analyzed and calculated.By establishing the relationship between the phase current and the internal magnetic field strength of the motor,the influence of temperature rise on the core magnetic field strength and the electromagnetic force on the stator is studied,and the correlation between the vibration and temperature rise of switched reluctance motor is revealed.In view of the phenomenon that the motor vibrates greatly during heavy load starting,the field circuit coupling analysis method is used to build a speed current double closed loop control circuit to optimize the starting current,torque and radial electromagnetic force.Based on the harmonic response analysis method,the vibration deformation frequency distribution of the motor stator and casing before and after the double closed loop control circuit is compared and analyzed.The results show that the double closed loop control mode can effectively weaken the low frequency vibration of the motor,which provides a reference for the design of the switched reluctance motor and the system.