An analysis of noise reduction in variable reluctance motors using pulse position randomization.
Authors
Smoot, Melissa C.
Subjects
Advisors
Kassakian, John G.
Date of Issue
1994
Date
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
The design and implementation of a control system to introduce randomization
into the control of a variable reluctance motor (VRM) is presented. The goal is to reduce noise generated by radial vibrations of the stator. Motor phase commutation
angles are dithered by 1 or 2 mechanical degrees to investigate the effect of
randomization on acoustic noise. VRM commutation points are varied using a uniform probability density function and a 4 state Markov chain among other methods.
The theory of VRM and inverter operation and a derivation of the major source of
acoustic noise are developed.
The experimental results show the effects of randomization. Uniform dithering
and Markov chain dithering both tend to spread the noise spectrum, reducing peak
noise components. No clear evidence is found to determine which is the optimum
randomization scheme. The benefit of commutation angle randomization in reducing
VRM loudness as perceived by humans is found to be questionable.
Type
Thesis
Description
Series/Report No
Department
Naval Engineering
Electrical Engineering
Computer Science
Organization
Identifiers
NPS Report Number
Sponsors
Funder
Format
95 leaves.
Citation
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.