Research On Topology Optimization Of Electromagnetic Structure Based On Level Set Method

Topology optimization plays an essential role in daily production and life.Topology optimization can determine the material distribution in the design domain through optimization algorithm on the premise of meeting the design requirements,and find out the optimal topological structure.Compared with conventional design methods,the topology optimization can generate a novel structure,which can save materials and supply more choices for consumers.Based on this,more and more researchers focus on topology optimization technology to promote innovative product design.Using topology optimization to design structure can get the result topology more accurately.The topology optimization is mostly used in the fields of material mechanics and vehicle engineering,while the related research in the electrical engineering is very few,especially for design of electromagnetic structure.Based on the advantages of topology optimization and its research situation in electromagnetic field,in this thesis,a topology optimization algorithm based on level set method for electromagnetic structure optimization is studied.The main work is summarized as follows:Firstly,the traditional level set method process is summarized.It is combined with sensitivity analysis and topological derivative theory to improve the operation efficiency of the level set function and optimize the design domain opening hole.The operation flow of level set topology optimization method is introduced.The level set topology optimization method is applied to the field of electromagnetic structure.Secondly,to verify the feasibility of the suggested topology optimization method,the structural designs of magnetic actuators are taken as application example.Different topological structures are investigated under different mesh densities.Combined with the electromagnetic field finite element analysis,the crosswise electromagnetic attraction of the armature of the magnetic actuator is effectively increased,and the amount of ferromagnetic materials is reduced at the same time.In order to verify the applicability of the proposed topology optimization algorithm and the reliability of the optimization results,this thesis takes an interior permanent magnet synchronous motor as the research object,and combines the measurement optimization and topology optimization to optimize the motor performance and improve the working efficiency.The optimization algorithm based on the radial basis function response surface model is used to optimize the measurement of the permanent magnet to weaken the torque ripple.After determining the measurement of the permanent magnet,it is taken as the initial design of topology optimization for the rotor structure.The optimized region is a part of the edge of the rotor,and its torque ripple is optimized.By studying the material distribution under different element densities in the design domain,the performance indexes before and after optimization are calculated,and on the premise of ensuring reasonable changes in other properties,the level set topology optimization algorithm is used to optimize the design and reduce the torque ripple of the motor.At the same time,the sine extent of the back-electromotive force(EMF)waveform is improved.Finally,the main performance data of the motor before and after optimization are compared.From the results,it can be seen that the sine of the back EMF is better after optimization,which effectively suppresses higher harmonics and weakens the cogging torque.