一次側控制返馳式轉換器電路架構，因為不需要二次側回授電路，具有可減少回授元件所造成的能量損失及降低電路成本之優點。通常一次側控制返馳式轉換器藉由電流偵測電阻偵測一次側電流峰值與利用輔助繞組偵測輸出二極體導通週期來估測輸出電流。然而一次側電流峰值的偵測值與實際值會因為功率開關截止到二極體導通間的時間延遲產生誤差。目前為補償一次側電流峰值誤差的補償方法，多為利用偵測延遲週期計算誤差值後做補償。此方法應用前提是一次側電流在延遲週期內依然呈線性上升，然而功率開關寄生電容的存在使得一次側電流呈非線性變化。本論文提出利用偵測驅動電路電流做補償，以提高偵測一次側電流峰值的精確度。最後，本論文使用TMS320F28335 DSP 達到輸出電流控制的功能，並應用於輸入電壓130 V，輸出電流5 A，輸出電壓12 V，輸出功率為60 W的一次側控制返馳式電源轉換器以驗證此補償方法準確偵測一次側電流峰值之可行性。

Primary-side regulation (PSR) flyback converter has advantages of compact size, lower cost, and less power loss on devices because secondary-side feedback circuit is needless. In general, PSR flyback converter uses current sensing resistor to sense primary-side current peak value, and auxiliary winding to detect output diode conduction period, then output current can be estimated. However, there is existing error between the sensing value and real value of primary-side current peak value because of the time delay between power switch turn-off instant and output diode conducting instant. In prior researches, the compensation method of primary-side current peak value is to detect the delay period and estimate the current error with assuming that primary-side current increases linearly, but parasitic capacitances of power switch let primary-side current change nonlinearly actually. The current error compensation can be achieved by detecting the sink current of the gate driver circuit. Finally, the output current control is implemented with digital controller TMS320F28335, and applied to an input voltage at 130 V, output current of 5 A, output voltage of 12 V, and output power of 60 W flyback converter to verify the feasibility of proposed compensation method.

[1] M. T. Zhang, M. M. Jovanovic and F. C. Y. Lee, "Design considerations and performance evaluations of synchronous rectification in flyback converters," IEEE Trans. on Power Electronics, vol. 13, no. 3, pp. 538-546, May 1998.
[2] Hsing-Fu Liu and Lon-Kou Chang, "Flexible and low cost design for a flyback AC/DC converter with harmonic current correction," IEEE Trans. on Power Electronics, vol. 20, no. 1, pp. 17-24, Jan. 2005.
[3] J. Zhang, X. Huang, X. Wu and Z. Qian, "A high efficiency flyback converter with new active clamp technique," IEEE Trans. on Power Electronics, vol. 25, no. 7, pp. 1775-1785, July 2010.
[4] B. Wang, X. Ruan, K. Yao and M. Xu, "A method of reducing the peak-to-average ratio of LED current for electrolytic capacitor-less AC-DC drivers," IEEE Trans. on Power Electronics, vol. 25, no. 3, pp. 592-601, March 2010.
[5] J. Park, Y. Roh, Y. Moon and C. Yoo, "A CCM/DCM dual-mode synchronous rectification controller for a high-efficiency flyback converter," IEEE Trans. on Power Electronics, vol. 29, no. 2, pp. 768-774, Feb. 2014.
[6] T. H. Chen, W. L. Lin and C. M. Liaw, "Dynamic modeling and controller design of flyback converter," IEEE Trans. on Aerospace and Electronic Systems, vol. 35, no. 4, pp. 1230-1239, Oct. 1999.
[7] Y. Panov and M. M. Jovanovic, "Small-signal analysis and control design of isolated power supplies with optocoupler feedback," IEEE Trans. on Power Electronics, vol. 20, no. 4, pp. 823-832, July 2005.
[8] C. Chang and C. Chen, "An isolated output-feedback scheme with minimized standby power for SMPS," IEEE Trans. on Power Electronics, vol. 28, no. 11, pp. 5140-5146, Nov. 2013.
[9] Y. Lin, T. Liang and K. Chen, "IC design of primary-side control for flyback converter," in Proc. IEEE International Future Energy Electronics Conference, 2013, pp. 449-453.
[10] P. Hsieh, C. Chang and C. Chen, "A primary-side-control quasi-resonant flyback converter with tight output voltage regulation and self-calibrated valley switching," in Proc. IEEE Energy Conversion Congress and Exposition, 2013, pp. 3406-3412.
[11] Yongjiang Bai, Wenjie Chen, Xiaoyu Yang, Xu Yang and Jingjing Sun, "A novel constant current and constant voltage adaptive blanking regulation scheme for primary-side controlled flyback converter," in Proc. IEEE International Power Electronics and Motion Control Conference, 2016, pp. 1652-1659.
[12] S. Yang, T. Tsai, H. Chen, C. Chiu, K. Chen, Y. Lin, J. Lin and T. Tsai, "High accuracy knee voltage detection for primary-side control in flyback battery charger," IEEE Trans. on Circuits and Systems I: Regular Papers, vol. 64, no. 4, pp. 1003-1012, April 2017.
[13] B. Keogh, B. Long and J. Leisten, "Design improvements for primary-side-regulated high-power flyback converters in continuous-conduction-mode," in Proc. IEEE Applied Power Electronics Conference and Exposition, 2015, pp. 492-497.
[14] T. Liang, K. Chen and J. Chen, "Primary side control for flyback converter operating in DCM and CCM," IEEE Trans. on Power Electronics, vol. 33, no. 4, pp. 3604-3612, April 2018.
[15] B. K. Huang and T. J. Liang, Primary-side control IC for flyback converter with wide-range operation, Master Thesis, Department of Electrical Engineering, National Cheng-Kung University, Tainan, Taiwan, 2018.
[16] Y. Li and Z. Zhu, "A constant current control scheme for primary-side controlled flyback controller operating in DCM and CCM," IEEE Trans. on Power Electronics, vol. 35, no. 9, pp. 9462-9470, Sept. 2020.
[17] X. Xie, J. Wang, C. Zhao, Q. Lu and S. Liu, "A novel output current estimation and regulation circuit for primary side controlled high power factor single-stage flyback LED driver," IEEE Trans. on Power Electronics, vol. 27, no. 11, pp. 4602-4612, Nov. 2012.
[18] B. Balakrishnan, A. B. Djenguerian, K. Wong, and D. M. H. Matthews, “Method and apparatus of maintaining a constant load current with line voltage in a switching mode power supply,” U.S. Patent 6 781 357, Aug. 24, 2004.
[19] T. Y. Yang and J. Y. Lin, “PWM controller having a saw-limiter for output power limit without sensing input voltage,” U.S. Patent 6 674 656, Jan. 6, 2004.
[20] P. Huang, D. Chen, C. Chen and Y. Chen, "An adaptive high-precision overpower protection scheme for primary-side controlled flyback converters," IEEE Trans. on Power Electronics, vol. 26, no. 10, pp. 2817-2824, Oct. 2011.
[21] H. Chou, Y. Hwang and J. Chen, "An adaptive output current estimation circuit for a primary-side controlled LED driver," IEEE Trans. on Power Electronics, vol. 28, no. 10, pp. 4811-4819, Oct. 2013.
[22] C. Wu, Y. Chen and Y. Chen, "Primary-side peak current measurement strategy for high-precision constant output current control," IEEE Trans. on Power Electronics, vol. 30, no. 2, pp. 967-975, Feb. 2015.
[23] Texas Instruments, “ TMS320F2833x, TMS320F2823x Digital Signal Controllers (DSCs),” Apr. 2019. [Online].
Available:https://www.ti.com/lit/ds/symlink/tms320f28335.pdf?ts=1598578846080&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTMS320F28335