Design And Optimization Of High Acceleration Permanent Magnet Linear Motor

Permanent Magnet Linear Machines(PMLM)with high acceleration are essential in aerospace,advanced manufacturing,and electromagnetic ejection applications.Research on PMLM is crucial in the development of linear direct drive fields,and it is currently a research hotspot.Based on domestic and international PMLM research,machines above 5g are generally considered high acceleration and can exceed 10 g in high-speed machining applications.This thesis focuses on studying the topology of PMLM,analyzing the impact of structural parameters on performance,and designing and optimizing a high acceleration PMLM.The main research objectives are as follows:(1)Conducting electromagnetic and structural designs on PMLM to determine the initial primary motor parameters and establish the corresponding model.Firstly,we establish the effective motion model of PMLM and deduce the mathematical expression of motor thrust according to the design requirements of high acceleration PMLM.Then,we establish the equivalent magnetic circuit model of the motor for magnetic circuit design and determine the initial primary motor parameters.Finally,we establish the electromagnetic finite element model of the motor to study its no-load and load performance.(2)Analyzing and optimizing the structural and performance parameters of four different near-pole slot-matching topologies.Firstly,we analyze the impact of the primary and secondary motor’s structural parameters on motor performance parameters,starting from the two research directions of large thrust and light weight mover.Then,we use the evolutionary algorithm and the weighted average Taguchi method for global optimization.Finally,we find the design scheme of the linear motor with high acceleration and low thrust fluctuation.(3)Establishing and optimizing a water cooling system to address the issues of high electric load and high-temperature rise in the optimization scheme.Firstly,we establish the thermal resistance network model and propose a fitting expression of the average water temperature of the cooling water pipe and the prediction function of the maximum water pressure in the pipe.Then,we obtain the maximum water pressure and winding temperature that meet the threshold conditions as optimization objectives.Finally,we use the response surface model and evolutionary algorithm to solve the optimal pipe width and pipe spacing of the water-cooled topology.(4)Analyzing the thermal characteristics of high acceleration PMLM under three operating conditions.Firstly,we build the finite element model of the temperature field of the motor and calculate the temperature distribution under the continuous working system.We optimize the water flow velocity under the maximum water pressure condition that satisfies the threshold condition,indicating the important role of the water cooling system.Then,we analyze the allowable running time of the motor in short-term operation and the influence of load duration on motor performance.Finally,we verify the correctness of the finite element model construction process and theoretical analysis by comparing the thermal performance of a water-cooled PMLM with its finite element analysis results.In conclusion,the research work based on high acceleration PMLM and the analysis results obtained in this thesis provide an effective reference for designing other PMLM acceleration-related indicators,which has certain practical value.