This dissertation contains a comprehensive analysis of both non-coupled and mutually coupled switched reluctance motors with concentrated windings for an electric bicycle traction application. Multiple pole configurations are analyzed and compared for each motor type. Includes magnetic design, thermal analysis, and structural analysis. A prototype is designed, manufactured, and validated. / This thesis discusses the design of both a conventional non-coupled
switched reluctance motor (CSRM) and a mutually-coupled SRM (MCSRM) for
an exterior rotor e-bike application. Several novel pole configurations were
analyzed for each machine type, and the performance of the final CSRM and
MCSRM designs were compared for this application.
A commercially available e-bike permanent magnet synchronous motor
(PMSM) was purchased, reverse engineered, and validated to define the geometry
constraints and performance targets for the designs. Since switched reluctance
motors do not use rare-earth permanent magnets, they are often seen as a potential
low-cost alternative to permanent magnet machines. The goal of this research is to
explain the relative advantages of CSRMs and MCSRMs when compared to PMSM
machines for a direct-drive e-bike application. The final CSRM and MCSRM
designs are analyzed in detail; electromagnetic, controls, thermal, and structural
considerations are all studied. A prototype of the final CSRM design was
manufactured and validated experimentally, using a dynamometer setup.
The finalized CSRM design is shown to be competitive with the PMSM
machine when considering torque output, and is superior in terms of peak
efficiency, and high speed torque performance. However, the CSRM noise output
and torque ripple were not compared to the PMSM, and a less-common
asymmetric-bridge converter is required for the CSRM, which may hinder the
ability for the machine to be implemented into existing e-bike packages.
The high speed torque performance of the MCSRM is shown to be inferior
to both the CSRM and PMSM, as is the torque quality and efficiency. The MCSRM
is shown to be highly resistant to saturation which gives it the potential for high
torque output at low speed (if thermal limits are not breached), though low
saturation levels also contribute to low machine power factor. The MCSRM may
be better suited to lower speed, high torque applications, for this reason. / Thesis / Doctor of Philosophy (PhD) / This thesis studies the design process and analysis of two different motor
types, for an electric bicycle application. They are designed to replace a
commercially available permanent magnet synchronous motor (PMSM). This type
of motor is typically expensive due to the rare-earth magnet material it requires.
The two motors discussed in this thesis are switched reluctance motors (SRMs),
which do not require magnet material, and thus have the potential to save cost (in
addition to other benefits). One of the SRMs has magnetic fields that are
independently controlled (CSRM), and one has fields that are controlled together
to produce torque (MCSRM). The magnetics, control, thermal, and structural
aspects of the CSRM and MCSRM are studied in detail. Novel geometry
considerations (i.e. novel pole configurations) which impact the magnetics of each
machine are compared to find the best-performing configuration for each machine
type.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/23643 |
| Date | January 2018 |
| Creators | Howey, Brock |
| Contributors | Emadi, Ali, Mechanical Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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