Abstract:
This thesis presents an extension of the use of standard industrial
command and control equipment in different applications.
Three types of programmable logic controllers (PLC) are investigated as
the main controller for electrical machine torque estimation and also for
frequency spectrum analysis. The major drawback of the investigated low-cost
PLCs related to this topic is highlighted.
With high applicability in condition monitoring and fault detection, three
types of electrical machines' electromagnetic torque estimators are presented,
simulated, and experimentally tested on a high-speed data acquisition and
control platform based on cRIO-9086 chassis. Online and offline-obtained results
are given in the context of steady-state and dynamic load opperation.
An artificial loading method for electrical machines is given and
investigated as a niche application of the standard low-cost equipment. Two
identical induction machines without mechanical coupling driven by two identical
dc link-connected variable frequency drives are artificially loaded at phase-rated
RMS current. A low-cost PLC is used for command and control. A simple openloop
method with different loading reference types validates the synthetic
loading principle. A closed-loop control method is successfully used for
automatized thermal testing of both machines. Frequency spectrum analysis
presents the inverters and the machine windings' connection influences.
Comprehensive acceptable results related to the loss equivalency are obtained
from simulation.
A high-speed data acquisition and control system is used as a torque
estimator for online and offline analysis of a novel active torque pulsation
reduction method for rotary electromechanical systems with position-dependent
loading torques. A mathematical two-step method used for preliminary total
system inertia and loading torque detection is presented in detail and
experimentally validated.
