本論文旨在探討三相無刷直流風扇電動機之無轉軸偵測元件驅動系統的研製。文中，首先探討以脈波寬度調變控制與電壓控制，應用於三相無刷直流風扇電動機的速度控制。此外，利用相角調整方式與150度12步方波驅動方法，以提高電動機的轉速，並加入軟啟動與軟切換技術，改善電流脈動。
其次，本文提出一種轉軸角度估測器，藉由偵測反電動勢，獲得三相無刷直流風扇電動機的轉軸角度。文中使用量測端電壓當回授訊號，不需用到中性點，由端電壓與二分之ㄧ的直流匯流排電壓作比較，判斷反電動勢零點，以獲得電動機的換相點。
本文所研製之系統以數位信號處理器TMS320F2407為控制核心，用來處理零交越點訊號與產生開關驅動訊號。最後以實驗結果驗證其可行性與正確性。

This thesis proposes an implementation of a sensorless drive system for three-phase brushless DC fan motors. First, the pulse width modulation control method and the voltage control method are used in the speed control for a three-phase brushless DC fan motor. Next, by using the phase-adjustment method and the 150 degree driving method, the adjustable speed range can be extended. The soft-start technique and soft-switching technique are applied to improve the current pulsations.
After that, a rotor position estimator is proposed. By detecting the back emf, a rotor position of the motor can be obtained. The three-phase terminal voltages are measured and compared with a reference voltage, and then determine the zero crossing of the back emf. Then, the phase-commutation time can be determined from the zero crossing of the back emf.
A digital signal processor, TMS320LF2407, is used as the control center to process the zero crossing signals and to generate the driving signals of the power switches. Finally, some experimental results can validate the feasibility and correctness of the proposed method.

[1]孫清華 編譯，最新無刷直流馬達，全華科技圖書股份有限公司，2002。
[2]葉明財 編譯，小型電動機活用技術，全華科技圖書股份有限公司，1999。
[3]趙貴祥 編譯，DC無刷電動機與控制電路，文笙書局股份有限公司，1995。
[4]S. U. Chung, G. Y. Hwang, S. M. Hwang, B. S. Kang, and H. G. Kim, "Development of brushless and sensorless vibration motor used for mobile phone," IEEE Transactions on Magnetics, vol. 38, no. 5 ,pp. 3000-3002, Sep. 2002.
[5]J. P. Johnson, M. Ehsani, and Y. Guzelgunler, "Review of sensorless methods for brushless DC," IEEE IAS-1999, pp. 143-150, 1999.
[6]J. S. Kim and S. K. Sul, "New stand-still position detection strategy for PMSM drive without rotational transducers," IEEE APEC-1994, pp. 363-369, 1994.
[7]S. Ogasawara and H. Akagi, "An approach to position sensorless drive for brushless DC motors," IEEE Transactions on Industry Applications, vol. 27, no. 5, pp. 928-933, Sep./ Oct. 1991.
[8]G. Maiocchi and V. Giuseppe, “Start-up procedure for a brushless sensorless motor,” United State Patent US 5,343,127, 1992.
[9]S. H. Park, S. H. Bahng and N. J. Kang, "Sensorless brushless DC motor uses fast and reliable unbalanced three-step start," Power conversion and Intelligent Motion, vol. 22, no. 4, pp. 6, Apr. 1996.
[10]J. Shao, D. Nolan, and T. Hopkins, "Improved direct back EMF detection for sensorless brushless DC (BLDC) motor drives," IEEE APEC-2003, pp. 300-305, 2003.
[11]J. Shao, D. Nolan, and T. Hopkins, "A novel direct back EMF detection for sensorless brushless DC (BLDC) motor drives," IEEE APEC-2002 , pp. 33-37, 2002.
[12]J. Shao, D. Nolan, M. Teissier, and D. Swanson, "A novel microcontroller-based sensorless brushless DC (BLDC) motor drive for automotive fuel pumps," IEEE Transactions on Industry Applications, vol. 39, no. 6, pp. 1734-1740, Nov./ Dec. 2003.
[13]T. Kim, H. W. Lee, and M. Ehsani, "Position sensorless brushless DC motor/generator drives: review and future trends," IET Electric Power Applications, vol. 1, no. 4, pp. 557-564, July 2007.
[14]R. C. Becerra, T. M. Jahns, and M. Ehsani, "Four-quadrant sensorless brushless ECM drive," IEEE APEC-1991, pp. 202-209, Mar. 1991.
[15]J. C. Moreira, "Indirect sensing for rotor flux position of permanent magnet AC motors operating over a wide speed range," IEEE Transactions on Industry Applications, vol. 32, no. 6, pp. 1394-1401, Nov./ Dec. 1996.
[16]Toshiba company, TB6537P/F, Three-phase Full-wave Sensorless Controller for Brushless DC Motors, Feb. 2003.
[17]T. Schneider, T. Koch, and A. Binder, "Comparative analysis of limited field weakening capability of surface mounted permanent magnet machines," IEE Electric Power Applications, vol. 151, no. 1, pp. 76-82, Jan. 2004.
[18]C. T. Pan and J. H. Liaw, "A robust field-weakening control strategy for surface-mounted permanent-magnet motor drives," IEEE Transactions on Energy Conversion, vol. 20, no. 4, pp. 701-709, Dec. 2005.
[19]G. Jiao and C. D. Rahn, "Field weakening for radial force reduction in brushless permanent-magnet DC motors," IEEE Transactions on Magnetics, vol. 40, no. 5, pp. 3286-3292, Sept. 2004.
[20]G. K. Miti, A. C. Renfrew, and B. J. Chalmers, "Field-weakening regime for brushless DC motors based on instantaneous power theory," IEE Electric Power Applications, vol. 148, no. 3, pp. 265-271, May 2001.
[21]J. X. Shen, Z. Q. Zhu, and D. Howe, "Sensorless flux-weakening control of permanent-magnet brushless machines using third harmonic back EMF," IEEE Transactions on Industry Applications, vol. 40, no. 6, pp. 1629-1636, Nov./ Dec. 2004.
[22]王世杰，陳春暉，張朝信，新型三相直流無刷無感測器散熱風扇發達的開發，機械月刊，第三十三卷第四期，2007。
[23]S. Hirata, “Motor driving device,” United State Patent US 6,377,008, 2000.
[24]T. Hashimura, “Driving device for three-phase brushless motor,” United State Patent US 6,316,894, 1999.
[25]E. C. Lee, “Bemf crossing detection in PWM mode operation for sensorless motor control application,” United State Patent US 5,789,895, 1996.
[26]J. Shao, "An improved microcontroller-based sensorless brushless DC (BLDC) motor drive for automotive applications," IEEE Transactions on Industry Applications, vol. 42, no. 5, pp. 1216-1221, Set./Oct. 2006.
[27]C. H. Chen and M. Y. Cheng "A new cost effective sensorless commutation method for brushless DC motors without phase shift circuit and neutral voltage," IEEE Transactions on Power Electronics, vol. 22, no. 2, pp. 644-653, Mar. 2007.
[28]Q. Jiang, C. Bi, and R. Huang, "A new phase-delay-free method to detect back emf zero crossing points for sensorless control of spindle motors," IEEE Tranctions on Magnetics, vol. 41, no. 7, pp. 2287- 2294, July 2005
[29]C. H. Chen and M. Y. Cheng, "A new sensorless control scheme for brushless DC motors without phase shift circuit," IEEE PEDS-2005, pp. 1084-1089, 2005.
[30]L. Zhang, W. Xao, and W. Qu, "Sensorless control of BLDC motors using an improved low-cost back emf detection method," IEEE PESC-2006, pp. 1-7, 2006.
[31]G. J. Su and J. W. McKeever, "Low-cost sensorless control of brushless DC motors with improved speed range," IEEE Transactions on Power Electronics, vol. 19, no. 2, pp. 296-302, Mar. 2004.
[32]N. Kim, H. A. Toliyat, I. M. Panahi, and M. H. Kim, "BLDC motor control algorithm for low-cost industrial applications," IEEE APEC-2007, pp. 1400-1405, 2007
[33]A. Lelkes, J. Krotsch, and R. W. De Doncker, "Low-noise external rotor BLDC motor for fan applications," IEEE IAS-2002, pp. 2036-2042, 2002
[34]C. M. Wang, S. J. Wang, S. K. Lin, and H. Y. Lin, "A novel twelve-step sensorless drive scheme for a brushless DC motor," IEEE Transactions on Magnetics, vol. 43, no. 6, pp. 2555-2557, June 2007.
[35]G. Maiocchi and V. Giuseppe, “Start-up procedure for a brushless sensorless motor,” United State Patent US 5,343,127, 1992.
[36]M. Tursini, R. Petrella, and F. Parasilit, “Initial rotor position estimation method for PM motors,” IEEE Transactions on Industry Applications, vol. 39, no. 6, pp. 1630–1640, Nov./ Dec. 2003.
[37]H. A. Toliyat, L. Hao, D. S. Shet, and T. A. Nondahl, “Position-sensorless control of surface-mount permanent-magnet AC (PMAC) motors at low speeds,” IEEE Transactions on Industrial Electronics, vol. 49, no. 1, pp. 157-164, Feb. 2002.
[38]Z. Y. Pan and F. L. Luo, "Novel soft-switching inverter for brushless DC motor variable speed drive system," IEEE Transactions on Power Electronics, vol. 19, no. 2, pp. 280-288, Mar. 2004.
[39]Rohm company, BD6962FVM, 12V Signal-phase Full Wave DC Brushless Fan Motor Driver, June 2007.
[40]Sanyo company, LB1950V, Three-phase Brushless Sensorless Motor Driver, Sep. 1996.
[41]Sanyo company, LB1978V, Three-phase Half-wave Sensorless Motor Driver for Headphone Stereos, June 1999.
[42]新華電腦 編著，DSP從此輕鬆跑(TI DSP 320LF2407A)，台科大圖書股份有限公司。
[43]陳建武、徐永松與龔應時 博士，TMS320F/C24x DSP 控制器原理與應用，滄海書局。
[44]Spectrum Digital, eZdspTM LF2407A Technical Reference, 2003.
[45]Texas Instruments, TMS320LF/LC240x DSP Controllers System and Peripherals Reference Guide, 2000.
[46]Spectrum Digital, TMS320C2xx/C24x Code Composer User’s Guide, 2000.
[47]H. C. Chen and C.-M. Liaw, "Current-mode control for sensorless BDCM drive with intelligent commutation tuning," IEEE Transactions on Power Electronics, vol. 17, no. 5, pp. 747-756, Sep. 2002.
[48]X. Wang, Q. Li, S. Wang, and Q. Li, "Analytical calculation of air-gap magnetic field distribution and instantaneous characteristics of brushless DC motors," IEEE Transaction on Energy Conversion, vol. 18, no. 3, pp. 424-432, Sep. 2003.
[49]G. H. Jang and M. G. Kim, "Optimal commutation of a BLDC motor by utilizing the symmetric terminal voltage," IEEE Transactions on Magnetics, vol. 42, no. 10, pp. 3473-3475, Oct. 2006.
[50]J. X. Shen and S. Iwasaki, "Sensorless control of ultrahigh-speed PM brushless motor using PLL and third harmonic back EMF," IEEE Transactions on Industrial Electronics, vol. 53, no. 2, pp. 421-428, Apr. 2006.
[51]Z. Y. Pan and F. L. Luo, "Novel resonant pole inverter for brushless DC motor drive system," IEEE Transactions on Power Electronics, vol. 20, no. 1, pp. 173-181, Jan. 2005.
[52]K. Y. Cheng, and Y. Y. Tzou, "Design of a sensorless commutation IC for BLDC motors," IEEE Transactions on Power Electronics, vol. 18, no. 6, pp. 295-300, Nov. 2003.