Realization And Department Analysis Of Fractional-order Controller Based On LabVIEW

Fractional-order calculus theory is paid great attention since it appeared. Through300years of development, it has been successfully applied to practical engineering. There are a lot of problems worthy of study in the field of control. This paper studies fractional PIαDβ controller design methods and analyzes their control performance.With the development of power electronic technology and control technology, AC motor has been gradually replacing DC motor become the mainstream in speed control system. And as the main energy conversion mechanism of industrial production, the control of AC motor is related to all aspects of the industry production. The virtual instrument with high performance, scalability, less development time and seamless integration features. LabVIEW with the NI acquisition and control equipment can accomplish a variety of control and testing tasks. Therefore, this paper designed and built the speed test of AC asynchronous motor platform, implemented the fractional-order controllers by the LabVIEW software design platform, analyzed the control performance at last.This paper first analyzes the purpose and significance and research status of the topic, and then introduces some principles and definitions of fractional-order calculus. Then it described the methods of fractional calculus operator approximation discrete in detail which based on the direct discretization and indirect discretization. Fractional order PIαDβ controllers designed by direct discretization method that using Tustin+CFE and Al-Alaoui+CFE as examples, and get its digital expression of Z-domain. According to the best rational approximation method and frequency characteristics of transfer function designed and implemented a fractional order PIαDβ controller for indirect discretization method.During the system implementation by LabVIEW, the structures of acquisition and storage are being optimized and the structure of controller implementation improved. The control results show that, the expected control effects can be achieved for the two kinds of controller. The parameters of the controller which designed by indirect discretization method is easier to be adjusted than the others. And the parameters robustness of the controller designed by indirect discretization method is better than the controller designed by direct discretization method. Overall, indirect discrete method controller is better using in the AC speed control system.