具相位控制頻率校正功能之超音波換能器驅動電路設計及應用

Design and application of an ultrasonic transducer driver circuit with phase controlling frequency calibration

周士勛(Shih-Hsun Chou)

指導教授 ： 陳秋麟

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.11156

摘要

以壓電式超音波換能器進行發射或是接收等等的技術也廣泛應用在生活的各個領域中，例如：超音波影像、汽車倒車雷達、超音波淨水、醫學治療…等等。然而壓電材料的特性會隨著環境或是製程漂移等等因素而有所改變，使得其最佳的操作工作點也會隨之改變。因此在本論文中，將對壓電式超音波換能器的運作原理及其等效電路作詳細的探討，得知超音波換能器的最佳收發頻段，並以自動操作於此頻段為基準，提出一個電路能藉由相位控制的方式，主動尋找最佳收發頻率，並校正壓電材料偏差特性造成的頻率漂移，同時驅動超音波換能器，使之發射超音波。最後實作該電路並以驅動不同操作頻率的超音波換能器來作對應及驗證。實驗結果顯示，對於不同的超音波換能器，能將其操作在最佳收發頻率，並且其誤差小於0.15%。

關鍵字

超音波驅動電路 ； 相位控制 ； 鎖相迴路 ； 頻率校正

並列摘要

Piezoelectric transducer is the most application method for ultrasonic sensor. Ultrasonic sensor is widely used in our life such as automobile parking sensor, water cleaning system, medical imaging…etc. However, the characteristics of piezoelectric materials will change with the environment variation, the process deviation, the damage of the material…etc. Thus, the proper operation point for an ultrasonic transducer will be different from time to time and from the other transducers. In this thesis, equivalent circuit and the operation of the ultrasonic transducer is investigated in detail. With discuss, the most efficiency frequency will be known. Besides, a circuit can trace the proper operating frequency for an ultrasonic transducer by phase controlling, and driving ultrasonic transducer, is proposed in this thesis. Finally, the calibration circuit is implemented and verified by ultrasonic transducer which have different operating frequency. Experiment results show that ultrasonic transducers can drive at the most efficiency frequency with inaccuracy error less than 0.15%.

並列關鍵字

Ultrasonic transducer driving circuit ； Phase lock loop ； Phase control ； Frequency calibration

參考文獻

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