| Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 105 === With increasing climate change, greenhouse gas emissions has become a serious issue. To reduce these emissions, governments continue providing new standards stricter than they were. For example, Euro 6 standard has been implemented in EU and EEA member states in 2014, having a lower level of nitrogen oxide emissions in diesel cars. Taiwan will also implement new emission standard, planned to follow the Euro 6 standard, in 2019. With a lower emission level, internal combustion engine vehicles (ICEV) are getting harder to meet these standards, and will be eliminated from the new car market. For instance, petrol or diesel cars will not be sold in Norway by 2025, and Germany will also calls for a ban on combustion engine by 2030. Therefore, Cars with low exhaust emissions, hybrid electric vehicles (HEV), or zero exhaust emissions, electric vehicles (EV), have become the subject of research and production made by car makers. Electric motors, the main component in electric vehicle transmission system, are also getting more and more concerned. Beyond numerous kind of electric motors, squirrel cage induction motor might be the best candidate for electric vehicle because of its inexpensive cost, robustness and controllability. However, due to its complex interactions between stator and rotor harmonics, squirrel cage induction motors often suffer from parasitic torques, vibrations, noises and additional stray losses. Therefore, designing a squirrel cage motor with low harmonic effects is quite important for electric vehicle.
This thesis starts with a brief design procedure used in industrial, providing an interpretation of its physical meaning. This thesis also presents a novel analysis and design procedure for winding, allowing designers to determine winding factor of any order harmonic for arbitrary winding. On the other hand, this thesis provides derivations of slots combination preventing parasitic torques, noises and vibrations, additional stray losses. With these derivations, we realize that air gap flux density and the number of slots affect harmonic effect the most. Lastly, this thesis presents an innovative optimal design procedure for electric vehicle induction motor and apply this procedure to a2.2kw, four pole induction motor. As a result, efficiency, power factor and torque ripple are all significantly improved.
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