Analysis and Design of a Multi-resonant Converter with a Wide Output Voltage Range for EV Charger Applications

다국어 초록 (Multilingual Abstract)

This paper illustrates the analysis and design of a multi-resonant converter applied to an electric vehicle (EV) charger. Thanks to the notch resonant characteristic, the multi-resonant converter achieve soft switching and operate with a narrowed switching frequency range even with a wide output voltage range. These advantages make it suitable for battery charging applications. With two more resonant elements, the design of the chosen converter is more complex than the conventional LLC resonant converter. However, there is not a distinct design outline for the multi-resonant converters in existing articles. According to the analysis in this paper, the normalized notch frequency fr2n and the second series resonant frequency fr3n are more sensitive to the notch capacitor ratio q than the notch inductor ratio k. Then resonant capacitors should be well-designed before the other resonant elements. The peak gain of the converter depends mainly on the magnetizing inductor ratio Ln and the normalized load Q. And it requires a smaller Ln and Q to provide a sufficient voltage gain Mmax at (Vo_max, Po_max). However, the primary current increases with (LnQ)<SUP>-1</SUP>, and results in a low efficiency. Then a detailed design procedure for the multi-resonant converter has been provided. A 3.3kW prototype with an output voltage range of 50V to 500V dc and a peak efficiency of 97.3 % is built to verify the design and effectiveness of the converter.

목차 (Table of Contents)

• Abstract
• Ⅰ. INTRODUCTION
• Ⅱ. OPERATIONAL PRINCIPLES
• Ⅲ. ANALYSIS OF THE CIRCUIT PARAMETERS
• Ⅳ. ANALYSIS OF THE CIRCUIT PARAMETERS
• Ⅴ. EXPERIMENTAL RESULTS
• Ⅵ. CONCLUSIONS
• REFERENCES

참고문헌 (Reference)

1 B. Yang, "Topology investigation for frontend DC/DC power conversion for distributed power systems" Virginia Polytechnic Institute and State University 2003

2 R. Ren, "The third harmonics current injection scheme for LLC topology to reduce the RMS of the output current" 1435-1439, 2015

3 C. Fei, "State-trajectory control of LLC converter implemented by microcontroller" 1045-1052, 2014

4 Q. Chen, "Soft starting strategy of bidirectional LLC resonant DC-DC transformer based on phase-shift control" 318-322, 2014

5 M. Yilmaz, "Review of charging power levels and infrastructure for plug-in electric and hybrid vehicles" 1-8, 2012

6 Wenjin Sun, "Resonant Tank Design Considerations and Implementation of a LLC Resonant Converter with a Wide Battery Voltage Range" 전력전자학회 15 (15): 1446-1455, 2015

7 H. Pan, "Pulse-width modulation control strategy for high efficiency LLC resonant converter with light load applications" 7 (7): 2887-2894, 2013

8 A. Y. Saber, "Plug-in vehicles and renewable energy sources for cost and emission reductions" 58 (58): 1229-1238, 2011

9 J. Yamamoto, "PFM and PWM hybrid controlled LLC converter" 177-182, 2014

10 W. Feng, "Optimal trajectory control of LLC resonant converters for soft start-up" 29 (29): 1461-1468, 2014

11 D. Fu, "Novel multi-element resonant converters for front-end DC/DC converters" 358-364, 2008

12 Huiqing Wen, "Nonactive power loss minimization in a bidirectional isolated DC-DC converter for distributed power systems" 61 (61): 6822-6831, 2014

13 M. Kim, "New symmetrical bidirectional L3C resonant DC-DC converter with wide voltage range" 860-863, 2016

14 Y. Hu, "New modular structure DC-DC converter without electrolytic capacitors for renewable energy applications" 5 (5): 1184-1192, 2014

15 H. Wu, "Multielement resonant converters with a notch filter on secondary side" 31 (31): 3999-4004, 2016

16 Y. Jang, "Implementation of 3. 3-kW GaN-Based DC-DC converter for EV on-board charger with series-resonant converter that employs combination of variable-frequency and delay-time control" 1292-1299, 2016

17 Yihua Hu, "Design of a high-power, high step-up ratio modular DC-DC converter by the matrix transformer approach" 63 (63): 2190-2202, 2016

18 S. De Simone, "Design guideline for magnetic integration in LLC resonant converters" 950-957, 2008

19 F. Musavi, "Control strategies for wide output voltage range LLC resonant DC-DC converters in battery chargers" 63 (63): 1117-1125, 2014

20 A. Khaligh, "Comprehensive topological analysis of conductive and inductive charging solutions for plug-in electric vehicles" 61 (61): 3475-3489, 2012

21 D. Huang, "Classification and selection methodology for multi-element resonant converters" 558-565, 2011

22 R. Zheng, "Analysis and parameter optimization of start-up process for LLC resonant converter" 30 (30): 7113-7122, 2015

23 T. Mishima, "An LLC resonant fullbridge inverter-lin DC-DC converter with an anti-resonant circuit for practical voltage step-up/down regulation" 3533-3540, 2012

24 F. Musavi, "An LLC resonant DC-DC converter for wide output voltage range battery charging applications" 28 (28): 5437-5445, 2013

25 T. Mishima, "A sensitivity-improved PFM LLC resonant full-bridge DC-DC converter with LC anti-resonant tank circuitry" 32 (32): 2016

26 Haoyu Wang, "A pulse width modulated LLC type resonant topology adpated to wide output voltage range" 1280-1285, 2016

27 D. Huang, "A novel integrated multi-elements resonant converter" 3808-3815, 2011

28 H. Wang, "A novel approach to design EV battery chargers using SEPIC PFC stage and optimal operating point tracking technique for LLC converter" 1683-1689, 2014

29 B. K. Lee, "A PWM SRT DC_DC converter for 6. 6-kW EV onboard charger" 63 (63): 894-902, 2016