Research On Iron Loss Characteristics Of Permanent Magnet Synchronous Motor Made Of Soft Magnetic Composites Material

Soft magnetic composite(SMC)material is made from metal particles insulated each other through mold pressing.Different from silicon steel sheet materials,SMC material has high resistivity,magnetic and thermal isotropy,and small eddy current loss,which is suitable for application in high-frequency motors.The project is supported by the National Natural Science Fund―“study on thrust ripple and material core loss character of TPMLM made of soft magnetic composite material”.The accuracy of the calculation method of the iron loss by using the piecewise orthogonal decomposition method with variable coefficients and the advantages of iron loss for SMC materials at high frequency were verified through the calculation of iron loss and experimental comparison.Based on analysis of factors affecting iron loss and the characteristics of soft magnetic composite material,a SMC motor with a rated power of 1kW was made and gained series of results in this paper.To sum up,the paper includes the following contents:The first part,the calculation method of iron loss was studied and the experiment of motor iron loss was carried out.Firstly,the generation mechanism of iron loss was analyzed,and the advantages and disadvantages of many calculation models of iron loss were compared.The piecewise orthogonal decomposition method of variable was adopted to calculate iron loss with full consideration of the magnetization mode,harmonic loss,magnetic density and frequency.Then,SMC material was tested by ring specimen method and the coefficient of iron loss was obtained by software fitting.Secondly,the magnetization mode of each part of the motor and the size of each harmonic magnetic density amplitude was analyzed by Ansys finite element software.Once again the area of the motor area was divided and the iron loss was calculated and compared on each part of the motor.Finally,in order to verify the accuracy of the iron loss calculation and advantages of the high frequency of motor,the iron loss of motor of SMC material and common silicon steel sheet material were measured by anti-drag method and only rotor method.The difference between two measurements at the same frequency is the iron loss.The second part studied affecting factors of the motor iron loss,mainly from three aspects of the motor structure,different loads and different power supply modes.Firstly,according to the iron loss optimization criterion derived from literature,the influence of motor structure,including grooving on rotor and changing the number of slots on motor,on the iron loss was studied.Secondly,the effect of slot width and slot length on motor iron loss was analyzed by parametric simulation.Finally,the effect of different loads and the switching frequency of SVPWM on the motor iron loss were studied.In the third part,according to the electromagnetic design process and the conclusion of the influence of the motor cogging structure on the motor’s iron loss,a rated power of 1kW permanent magnet synchronous motors which stator and rotor material is SMC was redesigned with reference to the size of the original motor.The difference of iron loss and electromagnetic properties were analyzed between the original motor and the redesigned motor.