| Summary: | 碩士 === 國立成功大學 === 系統及船舶機電工程學系碩博士班 === 97 === The intensity of the magnets in permanent-magnet (PM) motors can increase as the motor size and output power increase. This causes difficulty in manufacture of large scale PM motors and consequently increases the cost. Post-assembly magnetization (PAM) can be treated as a solution to the above problem, which fabricates the motors before the magnet is magnetized by applying large current impulse on the motor stator windings. However, the impulse current required is usually in the scale of hundreds or even up to thousands of amperes and the conductor may not be able to sustain such a huge current. Moreover, due to the flux direction at the magnetization instant produced by the stator coils, the edges of magnets can bear a weaker field so that the two sides of the magnets can have a weaker magnetic intensity. This will reduce the overall air-gap flux density and affect the performance of the PM motor. Therefore, this thesis proposes a new post-assembly magnetization, i.e., two-step magnetization method to solve the above two problems. The magnetization current can thus be reduced and the edge of magnets can be fully magnetized.
Overall, this thesis designs the permanent magnet motors considering the two-step magnetization current. Finite element analysis is applied to simulate the magnetization and the motor performance. Experiments are carried out to verify the design and the proposed magnetization approach.
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