Optimization Design Of Integral-slot Machine With Low Vibration And High Torque Using Harmonic-shaped Permanent Magnet

Electrohydrostatic machine is a high-efficiency,reliable and accurate control system,which is broadly applied in naval ship rudder rotation,aircraft airfoil control and other motion control fields.The integral-slot distributed winding permanent magnet machine can serve as the execution equipment of electrohydrostatic machine with advantages of high torque density,high efficiency and low harmonics to satisfy the low vibration noise and high precision control application requirements of naval ship system.However,the large torque ripple of traditional integral-slot machine affects the control accuracy of servo system,limiting its extension and application in the servo field.Therefore,this paper proposes a multi-objective optimization strategy based on the innovative harmonic combination PM-shaped method,which balances the torque performance and vibration response,and tackles the challenge of the integer slot distribution winding permanent magnet machine torque performance and vibration response simultaneously.This paper’s research mainly focuses on the following aspects:1.Deriving the expressions of electromagnetic torque and electromagnetic force based on the coupling mechanism of PM magnetic field and armature magnetic field,and analyzing the contribution to the torque and vibration performance for the integral-slot machine.In order to eliminate the issue that the eccentric PM method is insufficient to balance the torque performance and vibration response of integral-slot machine,the feedback harmonic combination PM-shaped method is introduced to improve the machine torque and vibration performance comprehensively.2.Based on the Sinusoidal+third(Sin+3rd)harmonic-shaped PM machine,a multi-objective optimization strategy is proposed to balance the average torque,torque ripple and vibration response.Combining the response surface model and barebones multi-objective particle swarm optimization algorithm to optimize the harmonic-shaped PM parameters,and the optimal solution can be obtained quickly.The high average torque,low ripple,and low vibration characteristics of the target machine are verified by finite element simulation.3.The thermal performance of the Sin+3rd-sharped PM machine is analyzed by the lumped parameter thermal network and the finite element method.The heat transfer theory is utilized to calculate the temperature field parameters of various machine components,and the machine temperature distribution is obtained from the two methods to verify the design reasonableness of the harmonic-shaped PM machine.4.For the prototype,the modal properties are tested utilizing the hammering technique to verify the accuracy of the finite element method.Then,the experimental platform is built and the no-load back EMF,load torque and vibration acceleration of the machine at rated speed are measured.Finally,the average torque and torque ripple of the machine at rated speed for different currents are measured.The experimental data confirmed that the theoretical analysis and finite element simulation are highly reliable.5.Fabricate the prototype,install the experimental platform,and test the modal parameters by the hammering method to verify the accuracy of the finite element simulation.Then,the no-load back EMF,load torque and vibration acceleration of the machine at rated speed,the average torque and torque ripple under different operating conditions at rated speed are measured.Comparisons between the finite element simulation and experimental results are performed to confirm the validity of the optimal design of the low-vibration,high-torque integral-slot harmonic-shaped PM machine.