| Summary: | 碩士 === 國立虎尾科技大學 === 航空與電子科技研究所 === 103 === This thesis is focused on developing a driver system for the ceiling fan with the brushless dc motor. The brushless DC motor can be controlled with and without applying Hall sensors. The 16-pole motor with the sinusoidal back EMF can achieve stable torque at the sin wave voltage input by the fan controller. By using digital and linear Hall sensors, the brushless DC motor with the number posted outside the magnet-type detects and converts the rotor angle directly, and in accordance with the angle to give the corresponding voltage. Based on square wave voltage supply, the advantage is having low switching loss and rotor position without precise feedback, but relatively large torque ripple. In order to have the pure sin waveform current, the sin waveform current driver is discussed. But the relative sine wave pulse width modulation driving method requires more precise position of the rotor.
This thesis presents a sensorless starting method, to improve the driver system for brushless DC motor without reversing rotation. This method first test signals sent excitation voltage ceiling fan motor, then change decision by the DC-link current rotor position. The proposed scheme employs only one current sensor at DC-link side, and can be applied to a motor without knowing its parameters. After the beginning of the estimation of the position, then the control voltage output based on the angle, the motor starts to accelerate. The method can start from a standstill to realize high-speed operation of the sensorless motor ceiling fan drive system. Experimental results reveal with linear Hall sensor to verify the feasibility of the proposed start-up method.
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