Research On Field Oriented Control Acvariable Frenquency Speed Regulation With Parameter Indentification

The development of power electronic technology of AC speed regulating system provides the guarantee of the achievement of closed-loop control. Vector control is one of the most widely used control strategy. Through coordinate transformation and magnetic field orientation, the field components and the torque of the motor decouples, hence the above two components can be independently controlled, which helps to gain excellent performance as the DC motor speed control. The key to the implementation of the field oriented control is to obtain the rotor flux information. At present, although flux observation can be realized by using the indirect method, its accuracy decreases with the change of motor parameters, the decoupling relationship is destroyed, which led to the decreasing, even disorder of the system performance. On the other hand, with the influence of working condition, temperature, magnetic saturation, motor parameters will unpredictably change. For this situation, this paper adds the function of paramete r identification in the traditional vector control speed regulation system.Main aspects of work are as follows:First of all, this paper introduced the principle of coordinate transformation, constructed the mathematical model of three-phase asynchronous motor under different coordinate system, studied the vector control strategy which is based on rotor field oriented, and analyzed the the SVPWM modulation technology and the flux linkage which were involved in the paper in detail.For the bad influence of motor parameters on the performance of the system, this paper put forward the motor parameter online identification method which is based on the vector control on the experimental platform. Researched a rotor time constant online identification method based on model reference adaptation,. Based on the analysis of the stability and the adaptive rate, built a motor field-oriented control model with functions of parameter identification of induction, and a simulation analysis was carried out.Designed the main circuit of the motor drive system, protection circuit and control circuit. Intelligent power module IPM was used to replace the traditional discrete component, which simplified the circuit structure and improve the reliability of the system. The motion control circuit which is designed with PCI bus realizes the communication between PC and DSP, which can effectively make use of the advantages of both to satisfy an open experimental platform requirements.The simulation analysis on the vector control system with parameter identification function under the environment of MATLAB/simulink, proved the feasibility of the system. On the basis of open experiment platform, the human-computer interaction interface was designed in Visual C++ environment. Designed the field-oriented control with parameter identification functions optimization algorithm; The experimental results show that the proposed method can prevent the impact of parameter changes on the system. It has good dynamic and static characteristics.