Design and tuning of fractional order PID controller for speed control of permanent magnet brushless DC motor

Abstract

This paper deals speed control of a Permanent Magnet Brushless Direct Current (PMBLDC) Motor using Fractional Order PID (FO-PID) controller tuned with different algorithms for PMBLDC motor. The inherent advantages of the FO-PID over conventional are its added fractions variables. The FO-PID controller is a generalized form of PID controller in which order of integration (I) and differentiation is any real number. It is shown that the proposed controller, which has five independent parameters (Kp, Ki, Kd, λ, μ) to tune, provides a powerful framework to control PMBLDC motor. The gain of PID controller is obtained by conventional methods of Ziegler-Nicholas (ZN), Cohen Coon (CC) and Amstron-Hagglund (AH). The Oustaloup's method is used to approximate the fractional order. Integration (s-λ) and differentiation (sμ) order is tuned using Nelder-Mead (NM), Interior point (IP) and Active set (AS) algorithm. The controller analysis is presented with the plant to ascertain the performance of the PMBLDC motor. Improvement in transient performance of the system using FO-PID controller is observed in the comparative results.