Hybrid LLC and Full Bridge Paralleled Converter With Variable-Frequency Plus Phase-Shift Control for Wide Voltage Gain Range Application
LLC converters are attractive with their ability of enable to achieve soft switching, but there is a trade-off between voltage gain and efficiency in wide voltage regulation range applications. In this paper, a novel hybrid LLC and full-bridge (FB) converter is proposed for wide voltage gain applica...
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2025-01-01
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| Online Access: | https://ieeexplore.ieee.org/document/10813348/ |
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| author | Fangfang Chen Wenguang Chen Bo Hu |
| author_facet | Fangfang Chen Wenguang Chen Bo Hu |
| author_sort | Fangfang Chen |
| collection | DOAJ |
| description | LLC converters are attractive with their ability of enable to achieve soft switching, but there is a trade-off between voltage gain and efficiency in wide voltage regulation range applications. In this paper, a novel hybrid LLC and full-bridge (FB) converter is proposed for wide voltage gain applications. The converter consists of a half bridge (HB) LLC resonant converter and a switch-off current-clamp FB converter connected in parallel. The turn-off current of the LLC converter over the entire range is significantly reduced through the clamping operation of the FB converter. Consequently, all primary-side switches of LLC converter achieve zero-voltage switching-on (ZVS) and low-current switching-off (LCS), while secondary-side diodes achieve zero-current switching-off (ZCS), leading to a substantial reduction in switching losses. Furthermore, a smooth transition variable-frequency plus phase-shift control strategy is proposed to achieve wide-range of voltage regulation. The proposed control has three operation modes: variable-frequency with a shift angle <inline-formula> <tex-math notation="LaTeX">$\varphi $ </tex-math></inline-formula> is 0 mode, phase-shift mode, and variable-frequency with <inline-formula> <tex-math notation="LaTeX">$\varphi $ </tex-math></inline-formula> of <inline-formula> <tex-math notation="LaTeX">$\pi $ </tex-math></inline-formula>. These modes cover the low, medium, and high voltage gain ranges, respectively. A 7.5 kW-rated experimental prototype is designed to convert a 400 V input to a 150-750 V wide output. The prototype demonstrates a peak efficiency of 98.04% and maintains an efficiency of over 93.8% from 30% load to full load across the 150-750 V output range. |
| format | Article |
| id | doaj-art-24182293a0114cdebe94bb64de17ef87 |
| institution | Kabale University |
| issn | 2169-3536 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Access |
| spelling | doaj-art-24182293a0114cdebe94bb64de17ef872025-01-03T00:01:58ZengIEEEIEEE Access2169-35362025-01-01131295130610.1109/ACCESS.2024.352199010813348Hybrid LLC and Full Bridge Paralleled Converter With Variable-Frequency Plus Phase-Shift Control for Wide Voltage Gain Range ApplicationFangfang Chen0https://orcid.org/0009-0002-0476-9389Wenguang Chen1https://orcid.org/0000-0003-2128-640XBo Hu2https://orcid.org/0009-0005-1805-4829School of Electrical Engineering, University of South China, Hengyang, ChinaSchool of Electrical Engineering, University of South China, Hengyang, ChinaCollege of Electrical and Information Engineering, Hunan University, Changsha, ChinaLLC converters are attractive with their ability of enable to achieve soft switching, but there is a trade-off between voltage gain and efficiency in wide voltage regulation range applications. In this paper, a novel hybrid LLC and full-bridge (FB) converter is proposed for wide voltage gain applications. The converter consists of a half bridge (HB) LLC resonant converter and a switch-off current-clamp FB converter connected in parallel. The turn-off current of the LLC converter over the entire range is significantly reduced through the clamping operation of the FB converter. Consequently, all primary-side switches of LLC converter achieve zero-voltage switching-on (ZVS) and low-current switching-off (LCS), while secondary-side diodes achieve zero-current switching-off (ZCS), leading to a substantial reduction in switching losses. Furthermore, a smooth transition variable-frequency plus phase-shift control strategy is proposed to achieve wide-range of voltage regulation. The proposed control has three operation modes: variable-frequency with a shift angle <inline-formula> <tex-math notation="LaTeX">$\varphi $ </tex-math></inline-formula> is 0 mode, phase-shift mode, and variable-frequency with <inline-formula> <tex-math notation="LaTeX">$\varphi $ </tex-math></inline-formula> of <inline-formula> <tex-math notation="LaTeX">$\pi $ </tex-math></inline-formula>. These modes cover the low, medium, and high voltage gain ranges, respectively. A 7.5 kW-rated experimental prototype is designed to convert a 400 V input to a 150-750 V wide output. The prototype demonstrates a peak efficiency of 98.04% and maintains an efficiency of over 93.8% from 30% load to full load across the 150-750 V output range.https://ieeexplore.ieee.org/document/10813348/Hybrid LLC resonant converterwide voltage gainhigh efficiencynovel control strategies |
| spellingShingle | Fangfang Chen Wenguang Chen Bo Hu Hybrid LLC and Full Bridge Paralleled Converter With Variable-Frequency Plus Phase-Shift Control for Wide Voltage Gain Range Application IEEE Access Hybrid LLC resonant converter wide voltage gain high efficiency novel control strategies |
| title | Hybrid LLC and Full Bridge Paralleled Converter With Variable-Frequency Plus Phase-Shift Control for Wide Voltage Gain Range Application |
| title_full | Hybrid LLC and Full Bridge Paralleled Converter With Variable-Frequency Plus Phase-Shift Control for Wide Voltage Gain Range Application |
| title_fullStr | Hybrid LLC and Full Bridge Paralleled Converter With Variable-Frequency Plus Phase-Shift Control for Wide Voltage Gain Range Application |
| title_full_unstemmed | Hybrid LLC and Full Bridge Paralleled Converter With Variable-Frequency Plus Phase-Shift Control for Wide Voltage Gain Range Application |
| title_short | Hybrid LLC and Full Bridge Paralleled Converter With Variable-Frequency Plus Phase-Shift Control for Wide Voltage Gain Range Application |
| title_sort | hybrid llc and full bridge paralleled converter with variable frequency plus phase shift control for wide voltage gain range application |
| topic | Hybrid LLC resonant converter wide voltage gain high efficiency novel control strategies |
| url | https://ieeexplore.ieee.org/document/10813348/ |
| work_keys_str_mv | AT fangfangchen hybridllcandfullbridgeparalleledconverterwithvariablefrequencyplusphaseshiftcontrolforwidevoltagegainrangeapplication AT wenguangchen hybridllcandfullbridgeparalleledconverterwithvariablefrequencyplusphaseshiftcontrolforwidevoltagegainrangeapplication AT bohu hybridllcandfullbridgeparalleledconverterwithvariablefrequencyplusphaseshiftcontrolforwidevoltagegainrangeapplication |