Control System Design Of Permanent Magnet Synchronous Motors With Complex Disturbances

This topic of this thesis comes from the National Natural Science Fund and applied basic research plan of Yunnan province.It aims to study a control algorithm that can suppress the complex disturbances perturbed in the servo motion control system in order to improve the overall control performance.In this work,several controllers with disturbance rejection capability is designed,and their effectiveness is also verified by the simulation software.Finally,the proposed control for the permanent magnet synchronous motor is realized on the experimental platform.First,because the motor system is usually affected by current harmonics and variety of disturbances,resulting in speed fluctuations of the motor.The most direct factor is that there is a large harmonic content in the supply current of motor.With the development of clean energy,new energy sources such as photovoltaic are becoming more and more common,but there are a lot of harmonics in these power generation systems.This will affect the quality of power supply,and the quality of power supply often affects all sorts of electric equipment,such as harmonic current can increase the motor vibration.So,we first propose a method to reduce output current harmonics of the grid-connected inverter.We propose a composite control consisting of a PI control and a plug-in repetitive control,which suppresses the system output current harmonics.Moreover,in order to improve the robustness of the control system,we also analyze the robustness and stability of the high order repetitive control.Extensive comparisons to first order repetitive control are also provided.Finally,the simulation results show that the repetitive control is effective in the grid-connected inverter system.Secondly,this paper focuses on the anti-disturbances control technology of permanent magnet synchronous motor(PMSM)system.In view of the complex disturbances in the system,including internal and external disturbances,such as friction,load,torque and model error.We propose a controller based on a novel unknown input observer(UIO),wherein the disturbance observer compensates for these disturbances,reduces the motor output speed error,and improves the control accuracy of the servo motor.The proposed UIO is also compared with other observers.Simulations are provided to show the improved performance of the proposed UIO based controller.Then,due to the conventional speed control method using mechanical speed sensors,in order to reduce the hardware cost and reduce the system failure rate caused by the sensor,This paper also presents a novel control technology of PMSM without the speed sensor is developed.But speed closed-loop control is susceptible to interference like current harmonics,model errors,by speed observer method to achieve closed-loop speed control.An adaptive speed observer is designed to estimate the speed of the rotor to get speed closed loop.Then,for the complex disturbances in the system,we also apply the UIO control strategy to suppress all kinds of disturbances and improves control accuracy of the system.Finally,MATLAB simulation results show that it can not only reduce the complex disturbances in the system,but also provide a practical and simple control method for high precision servo control.Finally,practical experiments are conducted based on based on a permanent magnet synchronous motor system configured with DSP2812.The overall structure of this system is introduced including the hardware and software.Through the host computer software CCS is used in the experiment to implement the correct related variables graphics,such as speed,current waveform.And PWM waveforms can be obtained through the oscilloscope.