Research On 50kW Permanent Magnet Assisted Synchronous Reluctance Motor Used In Electric Vehicle

Rare earth permanent magnet synchronous motor has challenges of cost and safety for electric vehicle drive.Concentrated winding permanent magnet assisted synchronous reluctance machine(PMa Syn RM) has been proposed for this.Compared with general interior permanent magnet synchronous motor,while PMa Syn RM has the same power as rare earth permanent magnet synchronous motor,the former could uses ferrite permanent magnet material which reduces manufacturing costs significantly.On the other hand,PMa Syn RM has higher performance-price ratio,but also has the ability of resisting over-voltage risk caused by high speed and stability at high temperature.As a result,Ferrite permanent magnet assisted synchronous reluctance motor has good prospects in the field of electric vehicle drive.This paper firstly introduces the development status of electric vehicle drive motor and analyzes disadvantages of this motot, and then focuses on the current developments of permanent magnet synchronous reluctance motor-assisted motor used in electric vehicle drive at home and abroad.Secondly, A high performance 50 k W ferrite-based permanent magnet-assisted synchronous reluctance motor has been electromagnetic designed for an electric vehicle application. Positive and negative saliency ratio has been compared for static and dynamic properties, then the optimization of positive saliency ratio PMa Syn RM has been achieved as well as suitable pole/slot with fractional-slot concentrated winding. Secondly, this paper has discussed the calculation of d-q axis electromagnetic parameters of permanent magnet reluctance motor by the method of magnetic circuit and field analysis. The general steps of the motor circuit design has been analyzed and the principle of flux compensation also has been proposed.A series studies about comparison between fractional-slot concentrated ferrite PMa Syn RM and the distributed winding Nd Fe B PMa Syn RM has been conducted.Thirdly,due to poor operation condition and complexible working conditions,temperature field simulation analysis for electric vehicle drive motor has been conducted based on ANSYS Workbench.Stress analysis for permanent magnet assited synchronous reluctance motor has also been considered under the effects of temperature field. Field-circuit co-simulation with external circuit simulation on the basis of ANSYS Simplorer has been done as well as the low-temperature demagnetization of the ferrite which ensure the reliability of the motor design. Finally,5k W permanent magnet-assited synchronous reluctance motor has been built, the process of building prototype and experiment which constitutes load test and load test has been introduced at last. Then the experimental results has been analyzed and compared with the simulation results to verify the reasonableness of the motor design and guide further research afterwards.