碩士 / 國立成功大學 / 系統及船舶機電工程學系碩博士班 / 94 / Thruster motors of underwater vehicles often connect to driving circuits embedded in a water-sealed pressure case through water-sealed cables and connectors. Brushless DC motors (BLDCM) output commutation signals to the driving circuit by Hall effect sensors. This implies the requirement of a significant size and pin number for the connectors. Connectors for underwater applications are often expensive, and hence reduction of the pin number implies reduction of cost. Moreover, the weight of the cable, as well as the opening sizes for the connectors on the pressure case, can also be reduced. Thus, the pressure case can be more strengthened, and the water-proof capability can be improved. These advantages can be accomplished by adopting the sensorless driving technique.
In the investigated sensorless driving technique, by regulating the cutoff frequencies for a low-pass filter, the rotational speed for switching to the commutation mode at the start-up stage can be decreased. Also, a discussion is made on what condition the motor can be switched from the start-up mode to the commutation mode. In the commutation mode, an on-line phase shifter is used to compensate the error of phase lag caused by the low-pass filter. Finally, in order to increase the speed ratio, a hardware phase-lead circuit with its programming is constructed to allow the current phase to lead the voltage phase and increase the motor speed range. Experiment is conducted to verify the proposed technique.
| Identifer | oai:union.ndltd.org:TW/094NCKU5345037 |
| Date | January 2006 |
| Creators | Hung-Ju Liao, 廖鴻儒 |
| Contributors | Min-Fu Hsieh, 謝旻甫 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 99 |
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