| The combined permanent magnet and electrically excited winding together provide the air gap magnetic field,and the magnetic field is adjustable for the hybrid magnetic circuit drive motor,which has become an important development direction of the drive motor for new energy vehicles.This article proposed a hybrid magnetic circuit drive motor topology with a combination of convex electromagnetic and permanent magnet poles,and investigated the topology selection,parameter selection,magnetic field characteristics analysis,loss analysis and experimental verification.The main work of this article is as follows:According to the power matching principle of the new energy vehicle,the mathematical expressions for the power,torque and speed of the drive motor were derived,and the inner and outer diameter and axial length of the drive motor were determined accordingly.The drive motor topology selection,pole slot matching,air gap length,stator slot type and armature winding parameters of the drive motor were optimised in conjunction with the finite element method.A combined magnetic pole composed of V-shaped permanent magnets,radial permanent magnets,and surface mounted permanent magnets has been determined,which improved the magnetic field strength,air gap magnetic density fundamental wave amplitude,and output torque,and reduced the magnetic density distortion rate.The equivalent magnetic circuit of the drive motor was plotted,the set of flux equations was established,and the equations for the magnetic permeability of each part were given.The magnetic density of the electric excitation was resolved by iteration using the distributed magnetic circuit method,and it was proposed that changing the salient pole rate is an effective way to increase the air gap magnetic density.The optimal salient pole structure parameters were obtained using the Taguchi method,which enhanced the air-gap magnetic density amplitude.The magnetic field distribution of an inhomogeneous magnetic potential source composed of combined magnetic poles is analysed by the segmental equivalence method,and the parameters of each magnetic poles were optimised by the control variable method.Increasing the length and angle of the V-shaped permanent magnets can increase the output torque and reduce torque pulsation.A tubular magnetic barrier has been designed to reduce inter-pole leakage and improve the utilisation rate of the permanent magnet.Based on the magnetic field distribution under eccentricity,reasonably designed the optimal pole eccentricity and improved the sinusoidal distribution of air gap magnetic density waveform.The B-P curve was fitted to obtain the loss coefficients,and the stator was divided into four regions: tooth tip,tooth body,tooth root and tooth yoke,and the magnetic density analysis was carried out separately.The main magnetic density radial component existed in the stator teeth and the main magnetic density tangential component existed in the stator yoke.The core loss was calculated using the sine equivalent method,the radial tangential component method and the Fourier decomposition method.The influence of core material and stator slot size on the core loss was analysed,and the optimum stator slot size was determined using the Latin hypercube sampling method with the maximisation of magnetic density at point B of the center of the tooth tip and minimisation of core loss.The variation of eddy current loss of permanent magnets with speed and excitation current at rated load was investigated,and the static synthetic magnetic field under different excitation currents was analysed,at which time the magnetic field size could be steadily adjusted and the output torque of the drive motor was stable.A hybrid magnetic circuit drive motor vector control model was built to analyse the output response characteristics of the drive motor at no load and load start.The prototype was tried and tested and the results showed that the machine has low cogging torque,low core loss and high output efficiency. |
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