Electromagnetic Design And Loss Analysis Of Axial Sectional Claw Pole High Speed Motor With Permanent Magnet Outer Rotor

Axial sectional claw pole machine has not only the advantages of simple structure andlow cost, but also high torque and power density. The inter stator and iron core is made ofSMC, a new sort of soft magnetic composite materials, which could reduce eddy currentloss. It makes the designing and optimizing easier with structure of axial section andconcentrated winding which decouples the magnetoelectric effect in space and reduces thesize of machine. When working in high speed, the abandonment of mechanical speedvariator improves transmission efficiency. The claw pole machine could be widely used inmany fields, such as compressor, hybrid vehicle, adjustable-speed motor, servo motor,power generation and driven system. An axial sectional claw pole machine with outer PMrotor is designed in this paper, which is used in axial-flow type air compressor unit as agenerator, working in high frequency and speed.Firstly, dimensions inside and electromagnetic parameters of the generator arecalculated, based on characteristics of claw pole machine, high speed machine and materialSMC. When it works in high frequency and speed, mechanical strength of inter stator,maximal flux density and temperature rise become the problems of capital importance indimensions’ design, resulted from its new structure with outer rotor and axial section andthe soft magnetic composite material adopted in stator. Then an electromagnetic equivalentmodel is built according to characteristics of material in machinery, magnetic conductiveand heat dissipation. After that, dimensions inside and electromagnetic parameters of thegenerator can be worked out.Secondly, the approximate treatments in electromagnetic designing are corrected,based on study of the electromagnetic equivalent model by the finite-element analysis (FEA), and an one-section machine3D model is built in ansoft to simulate the distributionof flux density. Then, either static or dynamic simulation is made, working out the no-loadback electromotive force and cogging torque, putting forward the methods to weakencogging torque.Finally, calculate the losses of core and air friction. Compared with traditionalmachines, the losses of core and friction in claw pole machine are more, especiallyworking in high frequency and speed. Calculation of core loss mainly focuses on the interstator made of SMC. The method is working on the3D equivalent alternatingmagnetization instead of rotational magnetization. By picking up the maximal flux densityof each equispaced point, the total iron loss, magnetic hysteresis loss, eddy-current loss andadditional loss are all worked out respectively. Comparing to results calculated in ansoft,the model of core loss calculation is verified. In friction calculation, air friction takes overa large percentage. Simulation in workbench of the temperature both in entrance and exitof wind path gives a way to get the energy propagated, which is air friction loss.