基于端口阻抗特性的电机轴承电压高精度模型OA

Bearing electrical corrosion has become an increasingly frequent issue,posing a critical problem that urgently needs to be addressed in high-power-density electric drive systems.A bearing voltage model is essential for studying bearing electrical corrosion to assess the level of electrical corrosion and explore potential mitigation methods.However,existing models lack sufficient accuracy.This paper proposes a modeling approach for motor bearing voltage based on port impedance characteristics to evaluate and mitigate bearing electrical erosion. First,the testing method and results of the motor port impedance were presented using an impedance analyzer.An analysis of the motor port impedance characteristics was conducted to examine the impact of impedance parameters on bearing voltage modeling.Next,a high-frequency bearing voltage model was proposed utilizing a distribution-parameter circuit structure.This model allows flexible adjustment of the number of circuit units based on the series and parallel resonance points in the common-mode impedance curve,thereby extending the model's frequency range and improving impedance simulation accuracy.The principles for determining the number of circuit units in the model were given.Subsequently,a parameter identification method combining analytical calculations with optimization algorithms was proposed.This method derives initial values for the model parameters through analytical calculations,then uses optimization algorithms to refine the resistance parameters.The analytical formulas for the model parameters and the optimization process were provided.Finally,a motor bearing voltage testing platform was constructed,and the experimental electrical parameters and specifications of the measuring equipment were given.Simulation and experimental validation were conducted using a 60 kW automotive three-phase permanent magnet synchronous motor as an example. The simulation and experimental results are compared under operating conditions at motor speeds of 500,2 000,and 3 500 r/min.Experimental results show that the proposed model accurately simulates common-mode impedance across the entire frequency range.The simulation error for the steady-state amplitude of the bearing voltage is 5%,while the maximum error for peak voltage is 8.6%.These results validate the good consistency between the simulation and experimental data.Therefore,the proposed model can be used to evaluate motor bearing voltage levels and provide a reliable foundation for research on suppression methods. Unlike induction motors,the differential-mode impedance characteristics of interior permanent magnet synchronous motors depend on the rotor position at low frequencies,which must be taken into account during the model parameter identification process.However,the common-mode impedance characteristics are independent of the rotor position.Traditional bearing voltage models,due to limitations in model structure and the simplicity of the parameter identification method,often exhibit significant errors when simulating common-mode impedance in the mid-and high-frequency ranges.The proposed model flexibly determines the circuit structure and can describe the variation of common-mode impedance across the entire frequency range.The model,combining analytical calculations and optimization algorithms,improves parameter identification accuracy and enhances simulation precision.