The Researches On Iron Losses And Harmonic Losses Of Amorphous Alloy Permanent Magnet Motor

As a new type of soft magnetic material,amorphous alloy material features excellent magnetic performances.The iron losses of the electric machines will be decreased and the efficiency will be improved by replacing the traditional silicon steel cores with the amorphous alloy cores.But it is difficult to process the amorphous alloy cores,and the magnetic performances of the amorphous alloy material will be severely influenced by the processes.Besides,the losses of amorphous alloy motors are different from that of the silicon steel motors.It is very important to research the calculation methods,the influence factors and the decrease methods of iron losses and harmonic losses of the amorphous alloy motor to the development of the amorphous alloy permanent magnet motor industry.Facing to the fact that the magnetic performances of the amorphous alloy material will be severely influenced by the processes,the specific iron losses of the manufactured amorphous alloy cores were measured,the correction method of the iron loss calculation for the amorphous alloy cores with certain processes was proposed by analyzing the experimental results.A testing device was designed to research the influences of shrink fitting process to the magnetic performances of the amorphous alloy cores,the magnetic performances of the amorphous alloy cores were measured under several shrink range circumstances.The results show that,the eddy current losses of the amorphous alloy cores increase a lot after shrink fitting process,which leads to a deterioration of the magnetic performances of the amorphous alloy cores,and it is getting worse with the increase of the shrink ranges.The influences of annealing and solidifying processes to the magnetic performances of the amorphous alloy cores were analyzed based on experimental method.It is shown that,for the annealed amorphous alloy cores,the increase of loss caused by solidifying process is mainly the eddy current loss,while for the annealed amorphous alloy cores,the increase of loss caused by solidifying process is the hysteresis loss.Facing to the fact that the magnetic field of the axial flux amorphous alloy permanent magnet motor is three dimensional,it is difficult to exhibit the relations between the losses and the specifications of the motor by using 3D finite element analysis,and the 3D finite element analysis is quite time consuming.The multilayer equivalent model was improved in this paper,the analytical method of iron losses and harmonic losses for the amorphous alloy permanent magnet motor was proposed by considering the influences of carrier ratios and modulation ratios to the orders and amplitudes of the current harmonics in the stator windings.The calculation results of the analytical method were verified by the calculation results of 3D finite element analysis and the experimental results.Based on the proposed analytical multilayer equivalent model,the influences of air gap lengths to the iron losses and harmonic losses of the axial flux amorphous alloy permanent magnet motor were researched.The results show that,the iron losses and harmonic losses decrease with the increase of the air gap lengths.Facing to the fact that the fundamental frequency of the axial flux amorphous alloy permanent magnet motor is high because of its multi-pole structure,which means the carrier ratio is low.The influences of carrier ratios to the harmonic losses were researched when the motor was supplied by inverter,the decrease method of harmonic losses by avoiding 3 times' carrier ratios was proposed and applied to an axial flux amorphous alloy permanent magnet motor rated at 800 Hz.It is shown that,the harmonic losses decrease by using this method.The iron losses and harmonic losses of axial flux and radial flux amorphous alloy permanent magnet motors were measured,the correction method was verified then by comparing the experimental results and the calculated results.Two motors with the same structures and dimensions were produced,one of whose stator core was made of amorphous alloy material,while the other one's was made of silicon steel material.The losses and efficiencies were measured and compared,the reasons for the diversities were analyzed by considering the differences of the magnetic performances between amorphous alloy material and silicon steel material.