Structural Optimization And Performance Analysis Of Hybrid Permanent-magnet Interior V-Shape Variable-flux Machine

The commonly used methods of adjusting the air-gap magnetic field of permanent magnet synchronous machine,for example,weak magnetic expansion speed technology,hybrid excitation technology,have many shortcomings.In this paper,a hybrid permanent-magnet interior V-shape variable-flux machine(HPI-V-VFM)is investigated.The magnet pole of the machine adopts two kinds of permanent magnet,Nd Fe B material and Alnico material.By using the low-coercive-force feature of Alnico permanent-magnet material,apply a pulse current to the machine,broaden the speed range of the machine,and enhance the working efficiency of the machine in the whole speed range.In this paper,the main work includes the working principle of HPI-V-VFM,analytic calculation,rotor structure design and optimization,analysis of the electromagnetic performance,analysis of mechanical strength and analysis of wide speed performance.Firstly,the working curve of Alnico material is studied,and the working principle of HPI-V-VFM is investigated.Then,according to the structure of machine magnetic circuit,equivalent magnetic circuit models in the both positive and negative magnetization condition are set up,the electromagnetic calculation program is writed based on the equivalent magnetic circuit model,and use the combination field with road for the machine to do an electromagnetic calculation.And the analytical calculation results and the finite element results are analyzed and compared.Secondly,aiming at improve the electromagnetic performance,the sizes of two kinds of the permanent magnetic material are optimized,explore the influence law of two materials size on the performance of machine,and then to improve torque quality and reduce the effect of q-axis armature reaction on magnetic regulation as a target,the air gap and the rotor structure are designed,influences on the electromagnetic performance of machine of uneven air gap structure and magnetic separation groove are analyzed.Thirdly,the electromagnetic properties of the HPI-V-VFM are researched by finite-element simulation,including magnetic field distribution in different magnetization states,the air gap flux density,counter electromotive force,torque characteristics,inductance characteristic,and working point of Alnico material analysis.Then the stress and deformation of rotor under the maximum rotating speed is studied by simulation analysis method,and validate the rationality of the design of machine rotor structure.Finally,the vector control method of HPI-V-VFM is analyzed,by use of HPI-V-VFM has different electromagnetic properties in different magnetization states,a proper vector control method is needed.The torque-speed characteristic and machine efficiency are calculated under different magnetization states by simulation analysis method,and by comparison,the comprehensive efficiency and the optimal magnetization-state figure are obtained within the scope of full speed.