Mitigating Duty Cycle Limitation and Maximizing DC Voltage Gain in Switch Mode Power Supplies Utilizing Tapped-Inductor Topology: A Case Study with Buck Converter Analysis

Year 2024, Volume: 12 Issue: 4, 349 - 356

Cağfer Yanarateş , Aytaç Altan

https://doi.org/10.17694/bajece.1524034

Abstract

This paper presents a comparative analysis of tapped inductor (TI) buck converters versus conventional buck converter topologies, highlighting the advantages of TI buck converters. The primary motivations for using TI DC-DC converters in step-down applications, such as battery charging and photovoltaic emulator design, include significant input-to-output voltage differences resulting in low converter duty cycles, favorable peak-to-average current ratios, and overall conversion efficiency. In conventional buck converters, the DC voltage gain is determined solely by the duty cycle, leading to linear output voltage variation with the duty cycle for a given input voltage. In contrast, the DC voltage gain of TI buck converters depends on both the duty cycle and the turns ratio. While the operating principles of conventional and TI buck converters are similar, the TI topology offers a wider range of voltage step-down options based on the TI turns ratio. System characteristics are analyzed using the transfer function model for ease of use and pole-zero detection. The state-space averaging method, known for its simplicity, is applied with AC small signal analysis to derive transfer functions for both converter types. The results show that the use of a tapped rather than a conventional inductor does not alter the step-down characteristics of the conventional buck converter. Moreover, any DC voltage gain consistent with the conventional buck converter condition can be achieved at any duty cycle value by appropriate selection of the turn’s ratio, increasing flexibility in converter design.

Keywords

DC-DC power conversion, buck converter-based emulator, tapped inductor, photovoltaic emulator, duty cycle limitation, DC voltage gain

References

• [1] P. Azer, A. Emadi. "Generalized state space average model for multi-phase interleaved buck, boost and buck-boost DC-DC converters: Transient, steady-state and switching dynamics." IEEE Access, vol. 8, 2020, pp. 77735-77745.
• [2] F. Musavi, W. Eberle. "Overview of wireless power transfer technologies for electric vehicle battery charging." IET Power Electronics, vol. 7, 1, 2014, pp. 60-66.
• [3] Y. Wang, O. Lucia, Z. Zhang, Y. Guan, D. Xu. "Review of very high frequency power converters and related technologies." IET Power Electronics, vol. 13, 9, 2020, pp. 1711-1721.
• [4] P. Alavi, E. Babaei, P. Mohseni, V. Marzang. "Study and analysis of a DC-DC soft-switched buck converter." IET Power Electronics, vol. 13, 7, 2020, pp. 1456-1465.
• [5] G. M. Sung, C. T. Lee, Z. L. Chen. "Buck converter IC for brushless DC motor drive using voltage-mode PWM controller." IET Power Electronics, vol. 13, 12, 2020, pp. 2547–2554.
• [6] A. Chadha, A. Ayachit, D. K. Saini, M. K. Kazimierczuk. "Steady-state analysis of PWM tapped-inductor buck DC-DC converter in CCM." IEEE Texas Power Energy Conference (TPEC), College Station, TX, USA, 2018.
• [7] B. J. Tucker. "Understanding output voltage limitations of DC/DC buck converters." Analog Applications Journal, 2008, pp. 11–14.
• [8] V. Michal. "Dynamic duty-cycle limitation of the boost DC/DC converter allowing maximal output power operations." International Conference on Applied Electronics (AE), Pilsen, Czech Republic, 2016.
• [9] K. W. E. Cheng. "Tapped inductor for switched-mode power converters." 2nd International Conference on Power Electronics Systems and Applications, Hong Kong, China, 2006.
• [10] N. Kondrath, M. K. Kazimierczuk. "Analysis and design of common-diode tapped-inductor PWM buck converter in CCM." Electrical Manufacturing and Coil Winding Conference, Nashville, TN, 2009.
• [11] M. Rico, J. Uceda, J. Sebastian, F. Aldana. "Static and dynamic modeling of tapped-inductor DC-to-DC converters." IEEE Power Electronics Specialists Conference, Blacksburg, VA, USA, 1987.
• [12] H. Tarzamni, N. V. Kurdkandi, H. S. Gohari, M. Lehtonen, O. Husev, F. Blaabjerg. "Ultra-high step-up DC-DC converters based on center-tapped inductors." IEEE Access, vol. 9, 2021, pp. 136373–136383.
• [13] L. Wu, Y. Chen, S. Yang. "Design and research on tapped inductor of large step-up ratio DC/DC converter." IOP Conference Series: Earth and Environmental Science, vol. 617, 1, 2020, pp. 1-8.
• [14] D. K. Saini, A. Chadha, A. Ayachit, A. Reatti, M. K. Kazimierczuk. "Duty cycle and input-to-output voltage transfer functions of tapped-inductor buck DC-DC converter." IEEE International Symposium on Circuits and Systems (ISCAS), Florence, Italy, 2018.
• [15] J. H. Park, B. H. Cho. "Nonisolation soft-switching buck converter with tapped-inductor for wide-input extreme step-down applications." IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 54, 8, 2007, pp. 1809-1818.
• [16] C. S. Yeh, X. Zhao, J. S. Lai. "A MHz zero voltage switching (ZVS) tapped-inductor buck converter for wide-input high step-down low-power applications." IEEE 3rd International Future Energy Electronics Conference and ECCE Asia (IFEEC 2017-ECCE Asia), Kaohsiung, 2017.
• [17] J. Yao, K. Li, K. Zheng, A. Abramovitz. "On the equivalence of the switched inductor and the tapped inductor converters and its application to small signal modelling." Energies, vol. 12, 24, 2019, 4806.
• [18] D. A. Grant, Y. Darroman, J. Suter. "Synthesis of tapped-inductor switched-mode converters." IEEE Transactions on Power Electronics, vol. 22, 5, 2007, pp. 1964–1969.
• [19] A. Chadha, M. K. Kazimierczuk. "Small-signal modeling of open-loop PWM tapped-inductor buck DC-DC converter in CCM." IEEE Transactions on Industrial Electronics, vol. 68, 7, 2021, pp. 5765-5775.
• [20] S. Pal, B. Singh, A. Shrivastava. "High efficiency wide input extreme output (WIEO) tapped inductor buck-boost converter for high power LED lighting." IET Power Electronics, vol. 13, 3, 2020, pp. 535-544.