Optimization Design Of Radial Electromagnetic Force And Research On Vibration And Noise Characteristics Of Interior Permanent Magnet Synchronous Motors

With the world’s increasing attention to environment protection,energy safety and technological progress,energy conservation and environmental protection has become one of the themes of automotive technology development,which also brings a good opportunity for the development of the electric vehicle industry.The inter ior permanent magnet synchronous motor,with its advantages of high torque density and wide speed range,has become the main choice of electric vehicle drive motor.However,with the gradual development of drive motors in the direction of high power density and light weight,the problem of motor vibration and noise has become increasingly prominent.Among them,electromagnetic vibration and noise are more complicated and difficult to efficiently suppress.The main source of its generation is the radial electromagnetic force in the air gap.Therefore,the research on the generation mechanism of the radial electromagnetic force of the permanent magnet synchronous motor and the exploration of how to suppress the vibration and noise so that the permanent magnet synchronous motor can obtain the characteristics of high performance and low vibration and noise at the same time are of great significance in the research field of permanent magnet motors.This paper proposes a multi-objective optimization design method based on radial electromagnetic force to reduce the electromagnetic vibration and noise of the motor,and analyzes the influence of the single and double windings of the motor on the radial electromagnetic force distribution and vibration characteristics.In order to accomplish the above work,this paper has carried out radial electromagnetic force analysis,structural modal analysis and construction of electromagnetic field-structured field-noise field coupling multi physical field analysis model around two interior permanent magnet motors.The specific research work mainly includes the following aspects:1.The theory of no-load and load radial electromagnetic force is studied,and reveal its source and temporal and spatial distribution.On this basis,the harmonic distribution of radial electromagnetic force of two interior V-type permanent magnet motors with different winding structures is analyzed.The radial electromagnetic force is used as a bridge connecting the electromagnetic field and the vibration noise,and the radial electromagnetic force harmonics of the dominant vibration are selected.2.In order to suppress the vibration and noise of the motor while ensuring the basic output capacity of the motor,a multi-objective optimization design method based on the radial electromagnetic force is proposed.This method takes the dominated vibration harmonic of radial electromagnetic force,torque and torque ripple as optimization objectives.The sensitivity analysis method is used to solve the problem with the help of non-dominated sorting genetic algorithm(NSGA-II)to obtain the optimized size of the two motors.3.The finite element model of the entire stator system,including stator,housing,bracket and end cover,is established.The finite element method is used to carry out modal analysis on the motor structure,and the influence of the housing,bracket and end cover on the overall modal of the motor is explored.In addition,the modal shape and natural frequency of the motor in the free state and the restrained state are compared.4.The finite element software is used to construct an electromagnetic field-structure field-noise field coupling multi-physics analysis model to calculate the vibration and noise of the motor,and through the comparison and analysis of the vibration and noise of the two motors before and after optimization,the effectiveness of the optimization method is further verified.5.Process the prototype of interior V-type permanent magnet motor,build the experimental test platform,and carried out the basic electromagnetic performance experiments of the no-load back EMF and steady-state torque of the motor.The hammering method is used to conduct free-mode experiments on the motor stator system,and the motor is subjected to constant speed and variable speed vibration tests.Through the comparative analysis of simulation and experiment,the rationality and correctness of the theoretical analysis and optimization process are verified.