The Design And Speed Adjusting With Field Weakening Analysis Of PMSM Used In Electric Vehicle

With the increasing of energy sources consume and environment problem becoming more and more serious, and facing the concern of low-carbon economy of the whole society, the low-carbon economy has extended to the automotive industry. The requirements of energy saving and environmental protection are to promote the development of electric vehicles(EV), as the most clean electric vehicles, EV will be the main direction of the improvement of new energy vehicles. The high performance drive motor is the core of EV, which is also one of the key technologies in EV manufacture. The merits of high efficiency, wide speed range and high overload ability are required in EV. The permanent magnetic synchronous motor(PMSM) designed in this paper can meet the technical property requirements of EV.Firstly, based on the importance of study of EV, the development of drive motor's technology and research status in EV are summarized in this paper. An interior permanent magnetic synchronous motor is chosen, by comparing the advantages and disadvantages of various types of drive motor. Then, the structural characteristics and working principle of PMSM are introduced. Based on the main performance and technical requirements of drive motor in EV provided by design specification., the ontology design of PMSM is analyzed. The electromagnetic calculation program is designed, and make a computational analysis of example.Especially, water cooling method is used in the prototype to satisfy requirements of wide velocity modulation, high overload capacity of PMSM. The circular channel is set between the motor shell and the stator core. In this way, Heat is removed efficiently. Better temperature decrease effect could be achieved compared with the traditional cooling method, so the maximum permissible current density of winding is increased. The speed-adjusting range with field weakening in the PMSM is also increased. The two-dimensional finite element model of the PMSM prototype is established, Themagnetic field of the prototype was calculated and simulated by finite element method(FEM). Then, the air-gap flux density curves of no-load, armature winding and load were got. Based on the results of analysis, the main magnetic field is decreased because of d-axis armature reaction. In view of the control characteristics of PMSM in EV, the theoretical basis is provided for application in speed adjusting with field weakening, and the technical requirement of wide speed modulation range of PMSM is satisfied.