Study On Parameter Identification And Self-tuning Of Permanent Magnet Synchronous Motor Servo System

The PMSM servo system often adopts a three-loop nested control structure,which respectively control the torque,speed and position angle output by the motor shaft.In order to achieve a stable and fast response,the adjustment of the controller parameters is extremely important.The characteristic parameters of PMSM are the basis for controller parameter tuning.Inaccurate characteristic parameters will make the parameter tuning difficult.In addition,the moment of inertia of the load often changes,resulting in a decrease in the control performance of the servo control system.Since the position of the motor shaft is the integral of the speed,this paper mainly studies the parameter identification of the PMSM servo system and the parameter self-tuning of the speed loop controller.First of all,according to the mathematical model of PMSM,this article briefly introduces the control structure of the PMSM servo system;through the current controller design and speed controller design of the servo system,the parameter identification of the PMSM is explained.Necessity;Then the speed loop is analyzed using Bode diagram and time domain response.The analysis results show that the control performance of the speed loop is easy to decrease when the moment of inertia increases,which further elaborates the importance of the follow-up research in this paper.Then,this paper studies the off-line identification of the electrical and mechanical parameters of the PMSM.Taking the voltage equation and motion equation of the motor as the identification equation,according to the characteristics of the electrical and mechanical parameters in the identification equation,the identification excitation signal is designed for each parameter,and the identification method is deduced.The effectiveness of the off-line parameter identification method of PMSM is verified by simulation.Subsequently,in order to realize the self-tuning function of the speed loop PI controller parameters,this article is based on the idea of identification-adjustmentadaptation,first obtain the controlled object information,and then adjust the controller parameters.For the load torque,a disturbance observer is designed based on intermediate variables to observe;for the moment of inertia,a model reference adaptive moment of inertia identification algorithm based on the PI-type adaptive law is proposed,and it is combined with the Landau moment of inertia identification algorithm.In contrast,simulation shows that the algorithm has better convergence performance than Landau’s algorithm.Based on this,the mechanical parameter information obtained by online identification will be used to adjust the speed loop controller parameters according to realize the self-tuning function of the speed loop.Finally,the research content of this paper is verified by experiments on the physical experiment platform.The experimental results show that the methods of parameter identification and speed loop controller parameter self-tuning are effective.