Optimal Design Of Interior Permanent Magnet Synchronous Machine With Wide Speed Range

The interior permanent magnet synchronous machine (IPMSM) has become the best choice of drive motor for the electric vehicle because of its high power density, high efficiency, good torque control ability and wide constant-power speed range. For the electric vehicle has some special requirements for drive motor in small ripple torque and wider speed range, etc, the main work of this paper is finite element modeling and optimization for a7.5kW IPMSM, so that the motor meets the design requirements and performance with a wide speed range.At first, this paper analyzed the structure of rotor and the performance characteristics of IPMSM, then built the mathematical model based on rotor rotating coordinate system.Secondly, starting from the performance requirements of drive motor for the electric vehicle driving system, and with the aid of the2D finite element software, this paper respectively built two models of7.5kW-3-phase-8-poles IPMSM with different stator slots, which had two types of rotor topologies:rectangule and w-shape. Then the paper studied and analyzed influences of rotor topologies and stator winding using integer and fractional slots on flux-weakening performance, output torque, inductance, efficiency, cogging torque and no-load back-EMF, ctc. Thus7.5kW-3-phase-8-poles IPMSM model was selected as the best one.Finally, the finite element design results were compared with an electromagnetic calculation program. The comparison shows that the model is correct and optimal results not only meet the requirement of wide speed range on drive motor for the electric vehicle, but also display high efficiency, high power density and good torque control ability.