雖然適當的濾波器設計可以降低切換式電源的雜訊，滿足電磁干擾的要求。然而，被動元件中的寄生元件卻會影響濾波器的效能，無法有效地濾除切換雜訊。因此本論文主要研究目的為針對切換式直流電源轉換器，進行開關切換雜訊干擾之研究。藉由對電路與元件中寄生元件的分析，例如電容的等效串聯電感及電感的等效並聯電容，建立其等效電路，探討開關切換時產生的雜訊電流在電路的動作與對輸出訊號造成的影響。本文並以Buck電路進行研究與設計消除寄生元件的方法，最終成功實現一電容等效串聯電感補償技術。在實作結果與模擬軟體SIMPLIS上得到比較與驗證，所設計的ESL補償電感，在130 W的同步整流(SR) Buck硬切電路低壓與高壓條件測試下可成功抑制86.9%的開關切換雜訊。

Although an adequate filter design helps reduce the noise level of switching power supplies and satisfy the electromagnetic interference requirement; the parasitic elements within the passive components affects the filtering performance and fail to suppress the switching noise. This thesis presents the research on switching noise cancellation especially on DC-DC switching power supplies. The mechanism that induces switching noise is analyzed by considering the parasitics of the circuit components, such as the equivalent series inductance (ESL) of capacitors and equivalent parallel capacitance (EPC) of inductors. The results show that the parasitics indeed induce noise currents as the active switch is switching on and off. The noise current imposes on the output voltage to present as output switching noise. In this research, an ESL cancellation method that can effectively reduce switching noise by canceling the parasitics of output capacitor is studied. At last, this method is implemented and tested on a 130 W hard-switching synchronous rectified (SR) Buck converter. In comparison, about 86.9 % of noise reduction can be obtained in high voltage and low voltage output. The theoretical analysis is agreed with the experimental results.

[1] C. R. Paul, Introduction to electromagnetic compatibility. Hoboken, NJ: John Wiley and Sons, 1992.
[2] N. K. Poon, B. M. Pong, C. P. Liu, and C. K. Tse, “Essential-coupling-path models for non-contact EMI in switching power converters using lumped circuit elements,” IEEE Transactions on Power Electronics, vol. 18, no. 2, pp. 686-695, 2003
[3] M. Jin, M. Weiming, P. Qijun, K. Jun, Z. Lei, and Z. Zhihua, “Identification of essential coupling path models for conducted EMI prediction in switching power converters,” IEEE Transactions on Power Electronics, vol. 21, no. 6, pp. 1795-1803, 2006.
[4] S. Li, N. Jianhong, and W. Fengjiang, “Study on conducted EMI suppression method in PWM adjustable speed system,” in Proc. IEEE CIEP, 2003, pp. 2048-2055.
[5] P. Kong, S. Wang, and F. C. Lee, “Common mode EMI noise suppression for bridgeless PFC converters,” IEEE Transactions on Power Electronics, vol. 23, no. 1, pp. 291-297, 2008
[6] X. Huang, E. Pepa, J. S. Lai, S. Chen, and T. W. Nehl, “Three-phase inverter differential mode EMI modeling and prediction in frequency domain,” in Proc. IEEE LAS AMCR, 2003, pp. 2048-2055.
[7] S. Brehaut, J. C. Le Bunetel, D. Magnon, and A. Puzo,“A conducted EMI model for an industrial power supply full bridge.” in Proc. PESC, 2004, pp. 3227-3231.
[8] A. Massarini, and M. K. Kazimierczuk, “Self-capacitance of inductors,” IEEE Transactions on Power Electronics, vol. 12, no. 4, pp. 671-676, 1997.
[9] T. C. Neugebauer, and D. J. Perreault, “Parasitic capacitance cancellation in filter inductors,” IEEE Transactions on Power Electronics, vol. 21, no. 1, pp. 282-288, 2006.
[10] M. Rajabzadeh, “New design and implementation of an external passive circuit for cancelling the parasitic capacitance in filter inductors,” in Proc. IEEE PEDES, 2010, pp. 1-4.
[11] K. Piboonwattanakit, and W. Khan-ngern, “Parasitic capacitance cancellation of filter in power supply using mutual capacitance technique,” in Proc. IEEE ECTI-CON, 2008, pp. 1025-1028.
[12] S. Wang, F. C. Lee, and J. D. Van Wyk, “Inductor winding capacitance cancellation using mutual capacitance concept for noise reduction application,” IEEE Transactions on Power Electronics, vol. 48, no. 2, pp. 311-318, 2006.
[13] S. Wang, F. C. Lee, and W. G. Odendaal, “Cancellation of capacitor parasitic parameters for noise reduction application,” IEEE Transactions on Power Electronics, vol. 21, no. 4, pp. 1125-1132, 2006.
[14] M. A. Bueno, and A. K. T. Assis, “A new method for inductance calculations,” Journal of Physics D: Applied Physics, vol. 28, no. 9, pp. 1802, 1995.
[15] S. Wang, F. C. Lee, D. Y. Chen, and W. G. Odendaal, “Effects of parasitic parameters on EMI filter performance,” IEEE Transactions on Power Electronics, vol. 19, no. 3, pp. 869-877, 2004.
[16] S. Wang, F. C. Lee, and W. G. Odendaal, “Controlling the parasitic parameters to improve EMI filter performance,” in Proc. IEEE APEC, 2004, pp. 503-509.
[17] S. Wang, F. C. Lee, and W. G. Odendaal, “Characterization, evaluation, and design of noise separator for conducted EMI noise diagnosis,” IEEE Transactions on Power Electronics, vol. 20, no. 4, pp. 974-982, 2005.