Novel efficacious utilization of fuzzy-logic controller-based two-quadrant operation of PMBLDC motor drive systems for multipass hot- steel rolling processes

Abstract

This study investigates the rough steel-rolling process, which requires repeated and rapid bidirectional hot-rolling operations and proposes a fuzzy-logic-controller-based brushless electric DC (BLDC) motor drive system for the same. We present a modeling of the hot-steel rough-rolling process using a set of metallurgical parameters and mechanical equations based on their operating conditions, specific features and characteristics, all obtained from actual data. The above equations and related parameters were modeled in MATLAB/Simulink schematic under variations in temperature and slab thickness corresponding using three different hot-rolled (HR) steel specimens. This led to the creation of a pair of speed and torque- profiles with alternate polarities for successive passes covering the entire rolling process for each steel specimen. A fuzzy logic controller utilized the above profiles on the motor shaft by incorporating speed and current feedback loops to attain reference speed and calculation of instantaneous stator currents of the BLDC motor with respective phase sequences, so as to satisfy the torque-profile. Simulation results showing the detailed performance of the drive system are presented. Further, experimental work on a BLD-motor-drive system is presented, along with loading arrangements and an arm controller embedded with control algorithm for the multi-loop feedback system used for the closed loop speed control. The efficacy of the new applications proposed in this study for the first time can be seen from the validation of the results from the BLDC motor with its fuzzy-based controller in terms of simulation and hardware, thereby serving to be an attractive alternative to conventional induction motor drive systems for steel rolling.