| With the rapid development of economy and society,automobile,as a fast and comfortable tool,has been popularized widely.However,the increasing demand for automobiles leads to a substantial increase in the consumption of fossil fuels.At the same time,the carbon dioxide emitted by fuel vehicles has become the main source of greenhouse gas emission in the world,which greatly limits the sustainable development of human society.Electric vehicle(EV)has been paid more and more attention by various countries because of its advantages of low noise,energy saving and environmental protection.As the core component of EV,the drive motor should have the characteristics of large torque output with low speed,high power density,high efficiency and wide speed range.Due to the high-performances of rare earth permanent magnet,the stator permanent magnet(SPM)motor has the advantages of high power density and high efficiency.Moveover,the rotor of SPM motor is only a simple salient iron core,so that this kind of motor possesses the merit of good robustness and ease of cooling and heat dissipation.However,permanent magnets are single excitation sources for this kind of motor,which leads to the difficulty of the airgap magnetic field adjustment,and the speed range is deteriorated consequently.So the development of this kind of motor in the field of EV is limited.The magnetic field can be regulared by the control of excitation current in SPM based hybrid motors to expand its speed range.But the permanent magnet,armature winding and excitation winding are placed on the same stator.So the installation space of the three excitation resourses is limited greatly.In this paper,the concept of partitioned stator and the idea of DC-Biased sinusoidal current are introduced into the stator permanent magnet hybrid excitation motor,based on which a PS-DC-Biased HEM is proposed.The systematic research is carried out around the topological structure,operating principle,structural parameter design,electromagnetic performance analysis and experiment of the motor.The main contents of this paper are as follows:1.In view of the research background of electric vehicle drive motor,this paper proposes a PS-DC-Biased HEM,and introduces its topology in detail.The magnetic flux density waveform and harmonic content of the outer airgap are solved by the finite element method.On this basis,the connecting mode of the armature winding is configured according to the principle of magnetic field modulation.The magnetic flux enhancing and weakening principle of the motor is analyzed and verified by the finite element software.2.The power equation of PS-DC-Biased HEM is deduced to determine the basic size of the motor.Then,with the design objective of torque,magnetic flux adjustment rate and torque ripple,the main size parameters are analyzed and selected by JMAG software,so as to determine the processing parameters of PS-DC-Biased HEM prototype finally.3.The electromagnetic characteristics of PS-DC-Biased HEM,such as no-load magnetic field,armature reaction magnetic field,no-load flux linkage and induction electromotive force,cogging torque,output torque,inductance,are calculated and analyzed by JMAG.4.The loss of PS-DC-Biased HEM is calculated and analyzed.On the basis of obtaining the core magnetic density of each part of the motor,the core losses of the stator and rotor of the motor are simulated,and the core losses under different excitation conditions are obtained.According to the copper loss calculation formula,the copper loss of armature winding is calculated.Finally,the efficiency of PS-DC-Biased HEM under different excitation conditions is calculated by ignoring the mechanical loss and only considering the iron loss and copper loss.5.The prototype of PS-DC-Biased HEM is manufactured,and the difficulties in the manufacturing process of the prototype are described.The validity of the designed motor is preliminarily verified by measuring the no-load back-EMF of the motor. |
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