Fractional Order Direct Torque Control of Permanent Magnet Synchronous Machine

Abstract

This paper designs a fractional order PID direct torque control strategy for permanent magnet synchronous machine (PSMS) based on on fractional calculus. The fractional order controller to control the speed of the machine was synthesized, referring to Bode's ideal transfer function. In the controller, the fractional order integrator was approximated by Charef's method. The fractional PID order control was compared with classical PID control, showing that the former has the better accuracy and robustness. Finally, MATLAB/ SIMULINK simulation proved the advantages of our control strategy under oscillating torque load or magnetic field.

Analytical design of the fractional order controller and robustness verification

“…If the desired CLTF of (12) does not include the time delay element e -Ls , then the synthesized controller C (s) will have an unstable pole at 1/L, hence including the time delay element in (12) is mandatory. Substituting G (s) from ( 1) in (13), )𝐶(𝑠) (14) Comparing ( 13) and ( 14) and solving for C (s),…”

“…The parameters of the controller are obtained analytically using integral performance index and balanced state space methods [12]. Walid et al, developed a FOPID controller for the speed control of permanent magnet synchronous machine [13]. The controller is synthesized using the Bode's ideal open loop transfer function (OLTF).…”