Modeling And Optimal Design Of Double-sided Tubular Linear Motor With Tooth-cutting

The DSTLM has a more compact structure than the traditional single-sided linear motor,which has a higher power density,but it is usually accompanied by a higher detent force.Detent force mainly includes ending force and cogging force.Large detent force will seriously affect DSTLM’s efficiency and accuracy.In order to weaken the detent force,make it more suitable for wave energy conversion system or electric drive system.In this paper,the simulation model of DSTLM is established by 2D FEM,and the internal and external cogging force waveforms are analyzed.A new type of stator tooth-cutting topology is proposed from the perspective of weakening the cogging force.The SC mapping method was used to establish the analytical model of the magnetic field,and the optimizable parameters were found by analyzing the performance parameters of DSTLM.The DEA was used to establish the global optimization model of TC-DSTLM,and the best balance point was found between weakening the thrust ripple and reducing the average thrust.Dimension parameters of TC-DSTLM was used to make the experimental prototype.The experimental results show that the tooth-cutting model can weaken the cogging force of DSTLM and effectively suppress the thrust ripple at the expense of a small amount of average thrust.The main research contents of this paper are as follows:(1)Structure and performance analysis of DSTLM: The simulation model of DSTLM was established based on 2D FEM,and the air gap magnetic density of the internal and external of the motor was obtained.The cogging force,average thrust,thrust ripple and back-EMF were simulated and analyzed,and the theoretical basis for finding the optimization method was established.(2)The tooth-cutting topological structure of DSTLM: Due to the large detent force of the DSTLM,its output performance and control accuracy are seriously affected.It is necessary to suppress the thrust ripple by weakening its detent force.In this paper,according to the waveform’s characteristics in the period of cogging force,a tooth-cutting topology optimization structure is proposed,and its analytical model is established by using the SC method,which proves the effectiveness of this method to weaken the cogging force.A method of extending the stator’s end of DSTLM is adapted,the ending force of DSTLM is greatly reduced.In addition,in order to confirm the innovation of this method,the superiority of the tooth-cutting method is verified by comparing it with the stator shifting method.(3)Analysis and multi-objective optimization of TC-DSTLM: Since the TCDSTLM is a complex nonlinear system,its output performance has multiple measurement standards and is closely related to its size parameters.In this paper,the DEA is used for global optimization.The implementation steps are as follows: Firstly,the parameters,constraints and objective functions to be optimized are determined.Then,the analytical mathematical model and DEA are combined to optimize the motor’s model globally.Finally,the multi-objective optimization results are analyzed and the reliability is verified by FEM.(4)Prototyping and experiment of TC-DSTLM: the optimal structural size of TCDSTLM is obtained through the multi-objective optimization above.The experimental prototype is made and the experimental platform is designed.The actual output performance is measured through experiments,including the collection of experimental data such as cogging force,back-EMF and load back-EMF,and the results are compared with the FEM results and analytical results.The experimental results show that the new tooth profile topology proposed in this paper can effectively weaken the cogging force of DSTLM and suppress thrust fluctuations at the expense of its average thrust.