| The living standard of the people has improved with the rapid development of economic strength and the number of petrol vehicles increases rapidly.However,a large amounts of waste gas is discharged while a large amount of primary energy sources is consumed,which causes a great impact on people daily life.Electric Vehicle(EV)is an effective method to save energy and protect environment for its high efficiency characteristics,no pollution and low noise.As the core of the EV,the drive motor has a great influence on the overall performance of the EV.Based on the operating characteristics of the EV,it is necessary to design a suitable drive motor with wide speed range,high torque density and high efficiency.Based on the principle of magnetic field modulation,the permanent magnet vernier motor(PMVM)can improve the torque density and get extensive attention.Similar to ordinary permanent,the air gap of PMVM is directly excited by permanent magnets and it is difficult to adjust the magnetic field,so it is difficult to reach the speed regulation range of the electric vehicles requirement because it is not similar to the electric excitation motor to adjust the excitation magnetic field by adjusting the excitation current,which limits the promotion of applications.So in this paper,the concept of "hybrid excitation" is introduced into PMVM and a Hybrid Excitation Permanent Magnet Vernier(HE-PMV)motor is proposed.Besides,the topology,operation principle,structural parameter optimization,and performance analysis of HE-PMV was studied,and the prototype was made for experimental verification.The main contents of this article include:1)A HE-PMV motor is proposed and its topological structure is introduced.Besides,the air gap magnetic density is calculated by the equivalent magnetic circuit.Based on this,the operating principle of the motor is analyzed.In addition,the finite element software JMAG is utilized to calculate and systematically analyze the air gap flux density under the no-load condition of the motor,which verifies the accuracy and rationality of the analytical method.2)The power equation and torque equation of HE-PMV motor in low speed and high torque working mode are derived.On this basis,the main structural parameters of the motor are analyzed,and the structural parameters of the motor are finally determined.3)The finite element software JMAG was used to calculate and analyze the motor magnetic field distribution,permanent magnet flux,no-load induced electromotive force,positioning torque,inductance and torque in different working modes and even the magnetic modulation ability.4)The losses under the different operating modes of the HE-PMV motor were analyzed.Firstly,the magnetic flux density of the motor core is analyzed,based on this,the losses of the stator core and the rotor core in different modes are simulated.In addition,the copper loss generated by the two sets of windings at the rated current is calculated.Combined with the rated power of the motor in different working modes,the motor efficiency of HE-PMV under different working conditions is obtained.5)The prototype of HE-PMV motor was machined based on the optimized dimensional parameters,and the back-EMFs of the two sets of windings were measured by an oscilloscope to verify the correctness of the prototype. |
