| Summary: | 博士 === 雲林科技大學 === 工程科技研究所博士班 === 98 === The dissertation first uses the finite-element method (FEM) to simulate the properties of magnetic fields and electrical circuits for a single-phase brushless dc fan motor. The complete analysis for the inductance of the motor is made and the related results computed by FEM are utilized to establish the necessary model for the motor driving system.
In the analyses of the magnetic fields and electrical circuits, the distribution of static magnetic fields and the waveform of the cogging torque are simulated. Then the properties of electrical circuits including the winding inductance, back EMF voltage, and the actual condition of the motor operated at constant speed are established. The simulation results of electrical circuits are compared with the measurement results to confirm the accuracy of the simulation model.
Based on the FEM simulation model, the structure analysis and optimum driver design for the signal-phase brushless dc fan motor are proposed and discussed. There are four topics to be discussed in the dissertation.
1. Analysis of the asymmetric stator structure and optimum air-gap design for the stator.
2. An improved phase advance circuit for the single phase brushless dc fan motor.
3. The current waveform method for the optimum phase angle for the single-phase brushless dc fan motor.
4. Optimum efficiency driving design consists of Phase-Locked-Loop (PLL) for the single-phase brushless dc fan motor.
The related results computed by FEM are used to establish these four kinds of simulation models for the single-phase brushless dc motor driving system. And the theoretical analysis and the actual experimental results are also achieved.
All of the proposed items in the dissertation are very helpful to improve the characteristics for the single-phase brushless DC fan motor such as the efficiency, motor noise, and vibration which are recently concerned in the industry.
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