Predictive Torque Control Strategy for Speed Adaptive Flux Observer Based Sensorless Induction Motor Drive in Flux-Weakening Region

Abstract

In general, flux-weakening operation of induction motor (IM) drive to achieve control above the rated speed is challenging. The challenge further aggravates if the drive becomes speed sensorless. This article primarily focuses on the flux-weakening operation of adaptive flux observer-based speed sensorless IM drive working under a promising predictive torque control (PTC) regime. The flux-weakening operation, in this case, is more challenging because of the involvement of additional unavoidable estimation strategies essential for PTC algorithm, thereby further deteriorating drive's performance in the flux-weakening region if not addressed suitably. In this article, a simple flux and torque scaling factor-based approach is introduced in the PTC algorithm of the adopted sensorless IM drive to improve the performance in flux-weakening region. The drive's performance in terms of speed tracking is thoroughly investigated in MATLAB/Simulink. Moreover, stability study in the entire operating range has also been done in the same environment. Experimental results demonstrating the speed of operation up to 3.5 times the base speed as obtained with 2.2 kW IM drive interfaced with dSPACE ds1103 controller are also presented in this article.