Research On Conical-rotor Permanent Magnet Synchronous Motor For Lifting Equipment

The driving device of lifting machinery requires not only enough power, butalso the need for braking performance to reduce security risks. In this paper, theconical-rotor permanent magnet synchronous motor (CR-PMSM) is proposed, whichis able to output high torque and bring axial force for the brake. It is a new way oflifting machinery for its omitted gear reducer and high effic iency and saving space.This paper studies on direct-drive CR-PMSM and makes deep researches on itscharacteristics of magnetic field distribution, the axial magnetic force and torqueperformance.Firstly, This paper summarizes the development of the conical rotor motor andthe main research question of the low speed and high torque permanent magnetmotor, expounds the operational principle of the CR-PMSM for lifting machineryand the motor’ overall structure, moreover calculates the force and displacement ofthe matched butterfly spring. It is necessary to build the3-D model of finite elementmethod (FEM) after axial segmentation equably of the CR-PMSM and the analys isof the magnetic circuit model. For the big stator resistance of the low speed and hightorque permanent magnet motor, the special limiting trajectory of voltage andcurrent is proposed, then the control method of the CR-PMSM’ torque and the axialmagnetic force is analyzed, which is able to guide the design of the motor.Secondly, this paper researches CR-PMSM special flux distribution by using3-D FEM, including the distribution of air gap magnetic field of different cone angleand its radial and axial component, the law of the no-load flux and back EMF.Combination with the law of the special flux, the axial magnetic force of theCR-PMSM is discussed when it is no-load at different cone angle and axialdisplacement, moreover when it is load at different direct and quadrature axiscurrent. By the law of the axial magnetic force, it helps achieve the brakingrequirements of axial force through choosing reasonable design parameters.Furthermore, for output torque is one of the important performance parametersfor direct drive CR-PMSM, this paper analyses torque-angle characteristic atdifferent cone angle, and studies of different cone angle, the saturation effect onoutput torque, while its maximum torque is very important. For the big magneticflux leakage of the fractional slot concentrated winding, the slot leakage inductanceof double winding semi-closed slot is deduced theoretically. Then based on fourmagnetic lines of the end leakage, the end-winding leakage inductance ofCR-PMSM is put forward, which is able to get the length of the end winding.Finally, this paper makes the prototype according to the index and design plan,build the experimental platform, test the no-load characteristics, inc luding back EMF and the relations between no-load axial magnetic force and axia l displacement.Furthermore, direct axis current affected on the axial magnetic force is tested byexperiment.