Extended semi-analytical model of bipolar hybrid stepper motor

Abstract

The aim of this graduation thesis is to present a bipolar stepper motor semi-analytical model and compare its simulated motor dynamics. Stepper motor modeling has been successfully used to simulate motor performance and dynamics, yet, each modeling method holds advantages and disadvantages toward one another. In this thesis, the analytical modeling method is implemented for its faster simulation time. A semi-analytical model is constructed with motor non-linear entities on top of the motor analytical equations.

This thesis first examines and validates a finite element analysis model to extract such non-linear entities into lookup tables. A generalized electrical model and a flux-based model are constructed separately based on the analytical equation and lookup table. In a second stage, the motor dynamics from these models are compared and adapted to the semi-analytical model motor dynamics through non-linear parameters. Two methods to obtain the non-linear parameters, with and without motor measurements, are applied. Finally, Various motors with different parameters are simulated with the semi-analytical model. Comparison, accuracy, and limitations of the semi-analytical model is discussed. At the end of the thesis, conclusions are drawn from the simulated dynamics that a semi-analytical model can indeed be implemented to better simulate the motor dynamics; however, because of the estimation and measurements needed for the non-linear parameters, the semi-analytical model holds several limitations that made it less robust than the model with pure analytical equations.