Frequency Domain Identification Of Bldcm Control System

Microwave infrared scanner is an important portable equipment in meteorological Satellites. Scanning control system is the electrical control actuator of the scanner, and its performance decides the imaging accuracy of the scanner and the task completion of the satellites. Thus, studying methods and techniques to design a high precision scanning control system has practical sense.The design of control system contains not only hardware design but also software design which relates to researches on control algorithmic. Most algorithm is based on model. The precision of identified model decides the performance and feasibility of control algorithmic. Based on above reasons, this paper studies how to identify brushless DC motor control system. There are large numbers of identification methods, however this paper focuses on relay identification for its incomparable advantage over others from two aspects: simulation and practicality.Though simulation research, mathematical model of BLDCM control system is established, standard relay identification method is improved and continuous relay identification method which could apply to the identification of BLDCM control system is put forth. By using this method and through two relay test, parameters of the motor model could be obtained. Taking a BLDCM as an example, parameters of BLDCM model are obtained and the simulation results show that the continuous relay identification is effective and with high precision.In practical aspect, firstly, brushless DC motor control system is designed from two aspects: hardware and software. In the hardware design part, this paper makes full use of DSP ample hardware resources and completes the design of control system which contains a controller TMS320F2812 and some peripheral circuit, such as: speed detection circuit, serial communication circuit and the position detection circuit. In the software design part, this paper uses C-modular programming method, implementing functions of generating and updating PWM wave, electronic commutation, PID control and data communications. And the brushless DC motor runs well under the PID control. In addition, in order to facilitate real-time monitoring of motor speed, a serial port monitoring software is developed under VC++ 2005 platform. Secondly, this paper adopts a continuous relay identification method, identifies the mathematical model of designed control system. Experimental results show that the continuous relay identification method for brushless DC motor control system is effective.