Modeling Analysis And Control Of Servo System Based On Frequency Domain

Permanent Magnet Synchronous Motor (PMSM) has been widely used in social production, national defense technology, aerospace and other fields of science and technology. It plays an important role in the human development and social progress. Usually, when solving analysis and control the PMSM, the equation of state model in the time domain is used. Analyzing systems in the time domain is direct, and all the information you can obtain about the system is time-related, which is simple and easy to understand. However, the frequency response has a clear physical meaning, and it can be linked to the structure and system parameters conveniently. Frequency domain can reveal some phenomena which cannot be obtained in time domain. It is easy to adjust some parameters and components to improve the performance of the closed-loop system. Conduct the research about modeling, analysis and control of PMSM based on frequency domain can take the advantage of frequency analysis to engineering, and simplify the process of modeling, analysis and controller design. Furthermore, it can promote the application and generalization of this approach in practical engineering.Firstly, the basic structure and working principle of PMSM are introduced, and mathematical models in time domain and frequency domain are deduced in detail. Then the vector control program is discussed, and factors that cause model uncertainty are analyzed. After that, an identification scheme which has small calculation and is simple to operate is designed to obtain the frequency characteristic. Then, an identification algorithm improved by using iterative method is proposed to identify the transfer function of the speed loop of the PMSM. Based on the speed loop model obtained, convenient and efficient frequency domain controller design methods are studied. The PID controller is analyzed from the frequency domain, and then the PID controller parameters tuning methods based on the frequency domain targets and pole placement are proposed. The proposed practical methods simplified the process of parameter adjustment, and are easy to learn. Finally, the basic characteristics and the mathematical model of the flexible connection load are discussed. The proposed frequency domain identification modeling approach is extended to servo system with flexible connection load, and information about the resonant frequency, amplitude and phase is obtained, which verified the applicability and effectiveness of the proposed method. The obtained information provides a reference for the subsequent design of controller and notch filter.