新型超音波馬達有體積小和重量輕、低轉速時具有高扭力、無噪音、不會產生電磁波…等等的優點。相較於一般的電磁馬達，新型超音波馬達適用於一些特殊的場合，像是需要安靜或是無電磁波的地方，如辦公室、醫院…等等；或是定位精準的地方，如機器人、照相機自動對焦、精密定位控制、人工心臟、磁浮列車系統…等等。由於超音波馬達使用範圍廣泛，跟一般馬達比較起來有更多的優點，所以在社會被使用率越來越普及。
在傳統的驅動器方面，利用串聯共振方式產生兩相弦波驅動超音波馬達，但是驅動器易受品質因素影響，所以造成兩相振幅的不平衡，而且兩相弦波相位只能維持在正負90度。所以在控制速度方面，只能藉由控制頻率來控制速度。串聯共振在切換的時候，電壓和電流不一定會剛好在0準位，所以會有功率上的損失。在本論文中，提出一種新的驅動電路，設計架構簡單，材料獲取容易，成本低廉，具有高實用性。驅動方式藉由電壓控制頻率，頻率範圍在40~45 kHz、電壓控制相位，相位範圍可在正負90度之間，以及電壓回授達到穩壓功能。而且驅動方式因為不是使用切換的方式，所以沒有功率上的損失。應用在超音波馬達上面，可以得到精確而且快速的速度響應控制。
最後利用高精確度、不易受溫度變化與雜訊干擾的數位訊號處理器，來實現超音波馬達的定速控制。在本論文中，可以看到所提出的驅動器，可以展現良好的控制及高精度響應，並驗證驅動器在超音波馬達上面，有良好的實用性。

The traveling-wave ultrasonic motor (TWUSM) has the advantages that are small size, high torque when low rotational speed, and without noise and electromagnetic wave effect. The TWUSM is different to electromagnetic motor that it can be used in some special places which need quiet and no electromagnetic wave. Furthermore, the TWUSM is also applied in some places which need to be fixed accurately. Since the TWUSM is used generally and has more excellences than electromagnetic motor, the TWUSM is more and more popular.
The general driver usually uses serial- resonant to produce two-phase sine waves to drive TWUSM, but this driver is affected easily by quality factor such that the two-phase voltages would be imbalance. Since the two-phase voltage always keeps in positive 90 degree or negative 90 degree, the speed is only controlled by frequency. The serial- resonant inverter has zero voltage or zero current switching, so it would cause power loss. This thesis presents a drive system for the TWUSM that has the excellence like as design and obtain elements easily, cost cheaply, and high performance drive applications. The drive method of TWUSM is that frequency could be controlled and the range of frequency is between 40-45 kHz. The phase could be also controlled from positive 90 degree to negative 90 degree. In addition, the output voltage of the proposed drive is balance by voltage feedback control. The proposed drive also works without power loss.
From the experimental results for the TWUSM, the proposed drive is shown a superior performance and practicability. Furthermore, the implemental results are provided to demonstrate the effectiveness of the proposed drive circuit.

[1] K. Uchino, Piezoelectric Actuators and Ultrasonic Motors, Kluwer Academic Publishers, 1997.
[2] K. Uchino, ”Piezoelectric Ultrasonic Motors: Overview,” Smart Materials and Structures, vol. 7, pp. 273-285, 1998.
[3] A. Ferreira and P. Minotti, “High-Performance Load-Adaptive Speed Control for Ultrasonic Motors,” Control Engineering Practice, vol. 6, pp. 1-13, 1998.
[4] T. Senjyu, T. Kashiwagi, and K. Uezato, “A Study on High Efficiency Drive of Ultrasonic Motors,” Electric Power Components and Systems, vol. 29, pp. 179-189, 2001.
[5] T. Sashida and T. Kenjo, An Introduction to Ultrasonic Motors, Oxford University Press, New York, 1993.
[6] T. Senjyu, T. Kashiwagi, and K. Uezato, “Position Control of Ultrasonic Motors Using MRAC and Dead-Zone Compensation with Fuzzy Inference,” IEEE Trans. on Power Electronics, vol. 17, no. 2, pp. 265-272, March 2002.
[7] T. Senjyu, H. Miyazato, S. Yokoda, and K. Uezato, “Speed Control of Ultrasonic Motors Using Neural Network,” IEEE Trans. on Power Eleectronics, vol. 13, no. 3, pp. 381-387, May 1998.
[8] T. Senjyu, S. Yokoda, H. Miyazato, and K. Uezato, “Speed Control of Ultrasonic Motors by Adaptive Control with a Simplified Mathematical Model,” IEE Electv. Power Appl., vol. 145, no. 3, pp. 381-387, May 1998.
[9] K. T. Chau and S.W. Chung, “Servo Position Control of Ultrasonic Motors Using Fuzzy Neural Network,” Electric Components and Systems, vol. 29, pp. 229-246, 2001
[10] T. Senjyu, T. Kashiwagi, and K. Uezato, “A Study on High Efficiency Drive of Ultrasonic Motors,” Electric Power Components and Systems, vol. 29, pp. 179-189, 2001.
[11] G. Bal and E. Bekiro˘glu, “Servo Speed Control of Travelling Wave Ultrasonic Motor Using Digital Signal Processor,” Sens. Actuators A, vol. 109, pp. 212-219, 2004.
[12] F. J. Lin, R. Y. Duan, R. J. Wai, and C. M. Hong, “LLCC Resonant Inverter for Piezoelectric Ultrasonic Motor Drive”, IEE Electric Power Applications, vol. 146, no. 5, pp. 479-487, 1999.
[13] R. L. Steigerwald, “A Comparison of Half-Bridge Resonant Converter,” IEEE Trans. on Power Electronics, vol. 3, no. 2, pp. 174-182, 1998.
[14] R. J. King, and T. A. Stuart, “Inherent Overload Protection for the Series Resonant Converter,” IEEE Trans. on Aerospace and Electronic Systems, vol. 19, no. 6, pp. 820-830, 1983.
[15] R. Senani and D. R. Bhaskar, “Realization of Voltage-Controlled Impedances,” IEEE Trans. on Circuits and System, vol. 38, no. 9, pp. 1081-1086, September 1991.
[16] R. Senani and D. R. Bhaskar, “Versatile Voltage-Controlled Impedance Configuration,” IEE Circuits Devices System, vol. 141, no. 5, pp. 414-416, October 1994.
[17] R. Senani and D. R. Bhaskar, “A Simple Configuration for Realizing Voltage-Controlled Impedances,” IEEE Trans. on Circuits and System, vol. 39, no.1, pp. 52-59, January 1992.
[18] T. Sashida, and T. Kenjo, An Introduction to Ultrasonic Motors, Oxford University Press, New York, 1993.
[19] T. Senjyu, K. Uezato and H. Miyazoto, “Adjustable Speed Control of Ultrasonic Motors by Adaptive Control,” IEEE Trans. on Power Electronics, vol. 10, no. 5, pp. 532-538, 1995.
[20] J. Wallaschek, “Contact Mechanics of Piezoelectric Ultrasonic Motors,” Smart Mater. Struct., vol. 7, pp. 369-381, 1998.
[21] F. J. Lin, R. J. Wai, and C. M. Hong, “LLCC Resonant Inverter for Piezoelectric Ultrasonic Motor Drive”, IEE Proc. Electr. Power Appl., vol.146 , no.5, pp. 479-485, 1999.
[22] D. Sun, J. Liu, and X. Ai, “Modeling and Performance Evaluation of Travelling-Wave Piezoelectric Ultrasonic Motors with Analytical Method”, Sens. Actuators A, vol.100, pp. 84-93, 2002.
[23] A. Ferreira and P. Minotti, “High-Performance Load-Adaptive Speed Control for Ultrasonic Motors”, Control Engineering Practice, vol.6, pp.1-13, 1998
[24] T. Senjyu, T. Kashiwagi, and K. Uezato, “A Study on High Efficiency Drive of Ultrasonic Motors”, Electric Power Components and Systems, vol. 29, pp.179-189, 2001.
[25] Robert F. Coughlin and Frederick F. Driscoll, Operational Amplifiers & Linear Integrated Circuits, Prentice-Hall International, 1998.