Research On Parameter Identification Of Permanent Magnet Synchronous Motor Considering Inverter Nonlinear Factors

Due to the influence of factors such as temperature,magnetic field,load changes,and nonlinear factors of the inverter during the operation of the permanent magnet synchronous motor,its parameters will change,mainly including stator resistance,direct-axis and quadrature-axis inductances,and permanent magnet flux.The parameter changes directly affect the control performance of the permanent magnet synchronous motor,leading to a deterioration in control effect.Therefore,accurate motor parameter identification technology is a prerequisite for achieving better control performance of the permanent magnet synchronous motor.Through the analysis of the mathematical model of the motor,it is found that there is an underdetermined problem when conducting multi-parameter identification.Traditional parameter identification algorithms cannot meet the requirements,so this paper adopts a method of coupling high-frequency injection identification algorithm and least squares identification algorithm to identify the motor parameters.In addition,there are nonlinear factors in the inverter during operation,which cause errors in the voltage and current of the motor.The input of the identification model requires voltage and current,and the existence of nonlinear factors in the inverter will reduce the accuracy of parameter identification,so compensation for the nonlinear factors is required.Firstly,this paper introduces the working principle of embedded permanent magnet synchronous motor,analyzes several vector control methods commonly used in motor control,and detailedly introduces the basic principle and control algorithm of space vector pulse width modulation technology.The regularity of parameter changes and the influence of parameter changes on the vector control of permanent magnet synchronous motor are analyzed,laying the foundation for the analysis of the inverter nonlinear factors in the following text.Secondly,the reasons for the nonlinear factors of the inverter are analyzed in detail,considering the zero current clamping phenomenon caused by the nonlinear factors.A disturbance observer is used to compensate for the nonlinear factors,and then compensation is made for the zero current clamping phenomenon.The accuracy of the compensation model is verified through simulation experiments.Then,the parameters of the permanent magnet synchronous motor are identified.When using the high-frequency injection algorithm to identify inductance,the identification accuracy of the direct-axis and quadrature-axis inductances under different injection frequencies is analyzed.To identify the stator resistance and permanent magnet flux,which require the direct-axis and quadrature-axis inductance parameters,the coupling of the high-frequency injection algorithm and the least squares algorithm is proposed for identification,and the identification accuracy of stator resistance and permanent magnet flux under different frequencies is analyzed.Then,the nonlinear factors of the inverter are added to the parameter identification algorithm model.Through simulation experiments,it is found that the addition of nonlinear factors leads to large errors in motor parameter identification accuracy and significant fluctuations after stabilization.After considering the compensation model,it can be observed through simulation experiments that the motor parameter identification accuracy is high after compensation and the fluctuation after stabilization is small.Finally,experiments are carried out on the established test rig,and it is verified that the proposed method can accurately identify motor parameters by comparing the identified parameter values with the actual values.