Single Degree of Freedom Solid Rotor Velocity Control Induction Drive
Name
roman-jcroman-mme-dme-2023-thesis.pdf
Description
Thesis PDF
Size
68.22 MB
Format
Adobe PDF
Checksum (MD5)
d48f372985f94d2a157587240efb1d1e
Author(s)
Roman, Jean C.
Advisor(s)
Trumper, David L.
Date Issued
June 2023
Publisher
Massachusetts Institute of Technology
Abstract
This thesis studies a single degree of freedom (DOF), two-pole, three-phase, solid rotor,
induction motor operating in closed loop angular velocity control via a proportional-integral
(PI) controller applying a constant amplitude, variable frequency drive.
The stator consists of six iron teeth, evenly spaced and pointing radially inward, wound
with 160 turns of copper wire each in a three-phase, two-pole configuration. A steel enclosure
houses the stator and is supported by a 3D-printed polylactic acid (PLA) enclosure. The
wiring is initially connected in wye configuration without a neutral wire but later converted
to three independent phases, each with its own input and output wire. The teeth have a
nominal air gap of 0.5mm with the rotor.
The rotor consists of a solid iron cylindrical core with a 1mm aluminum sleeve press
fitted on the outside. Two mechanical bearings center the rotor inside the stator. A single-
input single-output (SISO) PI controller commands three 750 mA amplitude currents with
variable frequency, and offset by 120 degrees to provide a 3-phase drive resulting in a rotating
magnetic field. Each coil is powered by a custom linear transconductance amplifier with 5
kHz bandwidth and 0.3 A/V DC gain.
The controller receives feedback through a contact-less magnetic encoder providing a
linear voltage measurement of the rotor’s angle. We differentiate the position measurement
to estimate the angular velocity of the shaft. A small diametrically magnetized cylindrical
permanent magnet (PM) is attached to the end of the shaft and constrained by a 3-D printed
PLA fixture. During operation, we produced up to 1.6 mNm of torque and velocities of up
to 8,000 RPM.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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