隨著電動車的雙電磁系統的發展，低電壓輸出端需要一個降壓式三埠直流轉換器。本論文提出了雙電池的新型高降壓三埠直流轉換器，其結合使用耦合電感與降壓轉換器，使能用較小匝數比及適當的開關占空比達到高降壓的功能與實現端口之間的獨立能量傳輸。本論文首先將介紹與分析雙電池的新型高降壓三埠轉換器的電路之特性與動作原理，具有四種動作模式: 主電池對輸出之單輸入單輸出模式、輔助電池對輸出之單輸入單輸出模式、雙電池單輸出模式及主電池雙輸出模式。接著將分析本論文所提並進行主要元件之設計，包括圈數比，耦合電感與開關電壓應力。最後以數位訊號處理器TMS320F28335作為主架構控制器，建立了一個實驗原型以驗證上述理論分析，主電池為300 V，輔助電池為48 V，輸出電壓為24 V，額定功率為300 W，其開關頻率為50 kHz。實驗結果顯示最高效率出現在 SISO II 模式，與20%負載時為96.4%。

With the development of dual battery systems in electric vehicles (EV), a step-down three-port converter is essential for the low voltage output port. In this thesis, a novel high step-down three-port converter (TPC) using two batteries is proposed. The proposed TPC is constructed by combining a tapped-inductor structure and a buck structure. As a result, it can achieve a high voltage conversion ratio while reducing the turns ratio of the tapped-inductor and operating at a reasonable duty cycle, as well as achieving independent power transfer among three-port. Four operating strategies of the proposed TPC are introduced: single input single output I (SISO I), single input single output II (SISO II), dual input single output (DISO), and single input dual output (SIDO). The operating principles of each mode of the three-port converter are analyzed, and design considerations of its magnetic components, turns ratio and voltage stress on power devices are discussed in this thesis. The digital signal processor, TMS320F28335, is used as the main controller. Finally, an experimental prototype is built to verify the theoretical analysis with a 300 V main battery, 48 V auxiliary battery, 24 V output voltage, and 300 W rated power at 50 kHz switching frequency. The highest efficiency occurring at SISO II, under 20% load, is 96.4%.

[1] R. Ramakumar, H. J. Allison, and W. L. Hughes, "Solar energy conversion and storage systems for the future," in IEEE Trans. on Power App. and Syst., vol. 94, no. 6, pp. 1926-1934, Nov. 1975.
[2] K. C. Tseng and C. C. Huang, “High step-up high-efficiency interleaved converter with voltage multiplier module for renewable energy system,” IEEE Trans. On Ind. Electron., vol. 61, no. 3, pp. 1311–1319, Mar. 2014.
[3] J. M. Lopez-Cruz, J. Leyva-Ramos, M. G. Ortiz-Lopez, and L. H. Diaz, "Switching regulator using a high step-up voltage converter for fuel-cell modules, "IET Power Electron., vol. 6, no. 8, pp. 1626–1633, Sep. 2013.
[4] S. M. Chen, L. S. Yang, T. J. Liang, and J. F. Chen, “A boost converter with capacitor multiplier and coupled inductor for ac module applications,” IEEE Trans. on Ind. Electron., vol. 60, no. 4, pp. 1503–1511, Apr. 2013.
[5] M. Korpas and A. T. Holen, "Operation planning of hydrogen storage connected to wind power operating in a power market," in IEEE Trans. on Energy Conversion, vol. 21, no. 3, pp. 742-749, Sept. 2006.
[6] M. R. von Spakovsky, M. W. Ellis, and D. J. Nelson, “Fuel cell systems: Efficient, flexible energy conversion for the 21st century,” Proc. IEEE, vol. 89, no. 12, pp. 1808–1818, Dec. 2001.
[7] C. Zhao, S. D. Round, and J. W. Kolar, "An isolated three-port bidirectional DC-DC converter with decoupled power flow management," in IEEE Trans. on Power Electron., vol. 23, no. 5, pp. 2443-2453, Sept. 2008.
[8] L. J. Chien, C. C. Chen, J. F. Chen, and Y. P. Hsieh, "Novel three-port converter with high voltage gain," in IEEE Trans. on Power Electron., vol. 29, no. 9, pp. 4693-4703, Sept. 2014.
[9] P. H. Tseng, J. F. Chen, T. J. Liang, and H. W. Liang, "A novel high step-up three-port converter," 2014 International Power Electron. and Applicat. Conference and Exposition, Shanghai, 2014, pp. 21-25.
[10] R. Faraji and H. Farzanehfard, "Soft-switched nonisolated high step-up three-port DC–DC converter for hybrid energy systems," in IEEE Trans. on Power Electron., vol. 33, no. 12, pp. 10101-10111, Dec. 2018.
[11] N. Vázquez, C. M. Sánchez, C. Hernández, E. Vázquez, and R. Lesso, "A three port converter for renewable energy applications," 2011 IEEE Int. Symp. on Ind. Electron., Gdansk, 2011, pp. 1735-1740, doi: 10.1109/ISIE.2011.5984324.
[12] H. F. Wu, K. Sun, S. Ding, and Y. Xing, "Topology derivation of nonisolated three-port DC–DC converters from DIC and DOC," in IEEE Trans. on Power Electron., vol. 28, no. 7, pp. 3297-3307, July 2013, doi: 10.1109/TPEL.2012.2221746.
[13] H. Y. Zhu, D. L. Zhang, B. W. Zhang, and Z. C. Zhou, "A nonisolated three-port DC–DC converter and three-domain control method for PV-Battery power systems," in IEEE Trans. on Ind. Electron., vol. 62, no. 8, pp. 4937-4947, Aug. 2015.
[14] H. F. Wu, J. J. Zhang, X. Q. Qin, T. T. Mu, and Y. Xing, "Secondary-side-regulated soft-switching full bridge three-port converter based on bridgeless boost rectifier and bidirectional converter for multiple energy interface," in IEEE Trans. on Power Electron., vol. 31, no. 7, pp. 4847-4860, July 2016.
[15] J. Y. Deng, H. Y. Wang, and M. Shang, "A ZVS three-Port DC/DC converter for high-voltage bus-based photovoltaic systems," in IEEE Trans. on Power Electron., vol. 34, no. 11, pp. 10688-10699, Nov. 2019.
[16] J. W. Zeng, W. Qiao, and L. Y. Qu, "An isolated three-port bidirectional DC–DC converter for photovoltaic systems with energy storage," in IEEE Trans. on Ind. Applicat., vol. 51, no. 4, pp. 3493-3503, July-Aug. 2015.
[17] H. F. Wu, K. Sun, L. L. Zhu, and Y. Xing, "An interleaved half-bridge three-port converter with enhanced power transfer capability using three-leg rectifier for renewable energy applications," in IEEE Journal of Emerging and Selected Topics in Power Electron., vol. 4, no. 2, pp. 606-616, June 2016.
[18] J. J. Zhang et al., "A three-port LLC resonant DC/DC converter," in IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 7, no. 4, pp. 2513-2524, Dec. 2019.
[19] Y. E. Wu and I. C. Chen, "Novel integrated three-port bidirectional DC/DC converter for energy storage system," in IEEE Access, vol. 7, pp. 104601-104612, 2019.
[20] S. S. Dobakhshari, S. H. Fathi, and J. Milimonfared, "A new soft-switched three-port DC/DC converter with high voltage gain and reduced number of semiconductors for hybrid energy applications," in IEEE Trans. on Power Electron., vol. 35, no. 4, pp. 3590-3600, April 2020.
[21] Kaiwei Yao, Mao Ye, Ming Xu, and F. C. Lee, "Tapped-inductor buck converter for high-step-down DC-DC conversion," in IEEE Trans. on Power Electron., vol. 20, no. 4, pp. 775-780, July 2005.
[22] Ferroxcube, “3C90 material specification,” Preliminary Datasheet, Sep. 2008.