The Research On PID Servo Control System Of Permanent Magnet Synchronous Motor With Sliding Mode Structure And Two-Degree-Of-Freedom

Permanent magnet synchronous motor is characterized by high efficiency,high reliability,high performance and simple structure and it is widely used in industrial production and national defense aerospace and other fields.Considering that servo control system which is composed of permanent magnet synchronous motor has the questions that modeling is not fine enough,the control model can't be monitored and controlled online,the output of the traditional sliding mode variable structure control system has buffeting and easy to cause torque fluctuations and other issues,a two degree of freedom PID control algorithm with double closed loop sliding mode variable structure is proposed in this paper.Sliding mode variable structure control for stator resistance estimation is used in the controller and two degree of freedom PID control of sliding mode variable structure with control variables is used in the outer loop.The effect of torque fluctuation and temperature change on the model accuracy is reduced to the minimum due to the introduction of sliding mode variable structure controller.The fusion of the two degree of freedom PID and the sliding mode variable structure is made by controlling the observation variables,which weakens the chattering of the variable structure control and the smoothness of the current curve is improved.In this paper,the mathematical model of permanent magnet synchronous motor is introduced firstly,DQ axis model,Park-Clark and IPARK transformation of the motor are analyzed in detail.Advantages and disadvantages of SPWM and SVPWM two kinds of PWM control technology are analyzed based on it and.SVPWM control method are chosen in this paper and implementation process of seven stage SVPWM is elaborated.Then,three closed loop servo control system structure and control ideas are explained in detail and stator resistance on-line estimation sliding mode variable structure current control algorithm and sliding mode variable structure PID speed loop control algorithm with two degrees of freedom are proposed.Simulink modeling and simulation of the whole servo control system is conducted based on position loop P control strategy and the feasibility of the control method is verified.Finally the servo motor controller was built using TMS320F28335 as the control core.The method of rotor position detection of motor and motor cold start,as well as software design process of speed calculation SVPWM are explained respectively.DSP minimum system,power supply system,encoder data acquisition and processing,analog digital conversion,temperature detection,communication interface,IPM isolation,DC bus over voltage and over current protection and other hardware circuit are designed based on Altium Designer.Finally the experiments of load mutation,low speed direct drive,zero speed lock etc.are conducted in the experimental platform for servo control of permanent magnet synchronous motor.The experimental results show that the control algorithm is feasible in the servo system of permanent magnet synchronous motor.