Research On Key Technologies Of Integrated Five-Phase Permanent Magnet Synchronous Motor For Electric Vehicles

With the rapid development of the electric vehicle industry,vehicle manufacturers have put forward higher requirements for the electric vehicle's power source-the motor,that is,high power density,high efficiency,strong thermal management capabilities,and wide speed range.In order to meet the high index requirements of electric vehicles for driving motors,this paper proposes a structural design of the integrated design of the motor and the controller,that is,the motor controller is placed at the end winding of the stator,and the controller directly controls the motor to reduce excess harness losses.The motor and the controller share a set of water-cooled casing,which greatly reduces the volume of the power module of the electric vehicle,thereby greatly improving the power density of the motor-controller.Through the given technical indicators,in the electromagnetic design of the motor,this paper fully considers the influence of the integrated motor control side on the motor side.According to the electromagnetic design process of the motor,a five-phase built-in permanent magnet with a peak power of 110 k W and a maximum speed of 15000 rpm is designed.Synchronous motor,and analyze and research the problems of motor pole slot matching,magnetic pole structure,loss suppression,temperature field,space vector modulation and so on.First,for the controller installed at the end of the stator winding,the motor structure design is carried out,the effect of the multi-phase fractional slot motor pole slot on the reluctance torque is studied,the electromagnetic simulation model is built,and the preliminary design of the electromagnetic scheme is completed.Secondly,the influence parameters of peak torque and maximum speed of the built-in motor in different current control strategies are studied and analyzed,and the influence rules of salient pole ratio and field weakening rate on peak torque and maximum speed under different conditions are studied and analyzed.The overload capacity and weak magnetic capacity of the V-type magnetic pole and U-type magnetic pole structure are studied and analyzed,and the influence rule of the U-type magnetic pole magnetic steel structure and thickness on the straight-axis inductance is analyzed to complete the final design of the electromagnetic scheme.Thirdly,study and analyze the change law of winding copper loss and rotor wind mill loss under different parameters.A zigzag channel structure is proposed to study the convective heat transfer coefficient of the zigzag channel with different channel numbers and pipe diameters.Build a simulation model of the motor temperature field to simulate and analyze the steady-state and transient temperature rise of the motor.Finally,the torque and current waveforms of five-phase motors under different space vector modulation strategies are studied and analyzed,a joint simulation platform of the motor and the controller is established,and the torque waveforms and effects of different space vector modulation strategies directly on the motor are compared and studied.Changes in motor losses.