| Permanent magnet synchronous motor (PMSM) is the key component of electric drive system for electric vehicles (EVs), extending high efficiency region is a powerful way to improve the travel distance under limited power supply. In order to handle the design method of high efficiency high power density PMSM, it is significant to study the iron loss distribution discipline and variation regulation. This thesis is focus on the iron loss analysis and motor design of PMSM for EVs, the main work is introduced as follows:Firstly, the iron loss calculation model of variable frequency supply is provided. Considering the influence of harmonic magnetic field and the non-uniform distribution, the magnetic flux density is analyzed in details. The iron loss distribution regulation is also analyzed, and then the stator is divided into several parts for iron loss calculation. Adopted this analysis method, a 7.5kW PMSM for EV has been calculated and tested, the errors between calculated and test results is 10%, the calculation method is validated.Secondly, a rated speed 4500/min, rated power 20kW PMSM for EVs is designed. From the perspective of high power density, the comparative analysis of different pole-slot combination and rotor structure is carried out, and then 8 pole-48 slots and"V"type rotor structure is determined for the prototype. A further optimization is going on through the auxiliary tank on the rotor cylindrical, the results show that when the auxiliary tank is located at 45°electrical angle, the motor iron loss is minimum. Prototype iron loss analysis shows that as the frequency increases, the stator iron loss increases; at low speed region, time harmonic eddy-current loss accounts for the majority part of stator iron loss.Finally, the prototype manufacturing and test is going on. Test results show that the prototype meets the design performance criteria. The iron loss error between calculated and test result is small, the source of error is analyzed. |
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