Resonant Tank Design Considerations and Implementation of a LLC Resonant Converter with a Wide Battery Voltage Range

Wenjin Sun,Hongfei Wu,Haibing Hu,Yan Xing 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6

This paper illustrates resonant tank design considerations and the implementation of a LLC resonant converter with a wide battery voltage range based on the fundamental harmonic approximation (FHA) analysis. Unlike the conventional design at zero load, the parameter K (the ratio of the transformer magnetizing inductor Lm to the resonant inductor Lr) of the LLC converter in this paper is designed with two charging points, (Vo_min, Io_max1) and (Vo_max, Io_max2), according to the battery charging strategy. A 2.9kW prototype with an output voltage range of 36V to 72V dc is built to verify the design. It achieves a peak efficiency of 96%.

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

Wenjin Sun,Xiang Jin,Li Zhang,Haibing Hu,Yan Xing 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4

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.

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

Sun, Wenjin,Jin, Xiang,Zhang, Li,Hu, Haibing,Xing, Yan The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4

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 $f_{r2n}$ and the second series resonant frequency $f_{r3n}$ 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 $L_n$ and the normalized load Q. And it requires a smaller $L_n$ and Q to provide a sufficient voltage gain $M_{max}$ at ($V_{o\_max}$, $P_{o\_max}$). However, the primary current increases with $(L_nQ)^{-1}$, 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.

Resonant Tank Design Considerations and Implementation of a LLC Resonant Converter with a Wide Battery Voltage Range

Sun, Wenjin,Wu, Hongfei,Hu, Haibing,Xing, Yan The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6

This paper illustrates resonant tank design considerations and the implementation of a LLC resonant converter with a wide battery voltage range based on the fundamental harmonic approximation (FHA) analysis. Unlike the conventional design at zero load, the parameter K (the ratio of the transformer magnetizing inductor L_m to the resonant inductor L_r) of the LLC converter in this paper is designed with two charging points, (V_{o_min}, I_{o_max1}) and (V_{o_max}, I_{o_max2}), according to the battery charging strategy. A 2.9kW prototype with an output voltage range of 36V to 72V dc is built to verify the design. It achieves a peak efficiency of 96%.

Genome-wide identification of auxin-responsive microRNAs in the poplar stem

Yang Lihua,Ping Tao,Lu Wenjin,Song Sangfa,Wang Jianli,Wang Qiao,Chai Guohua,Bai Yue,Chen Yan 한국유전학회 2023 Genes & Genomics Vol.45 No.8

Background Wood (secondary xylem) of forests is a material of great economic importance. Wood development is strictly controlled by both the phytohormone auxin and microRNAs (miRNAs). Currently, the regulatory mechanisms underlying wood formation by auxin-associated miRNAs remain unclear. Objective This report was designed to identify auxin-responsive miRNAs during wood formation. Methods Morphological observation of wood development in the poplar stems was performed under the treatment of different concentrations (0 mg/L, CK; 5 mg/L, Low; 10 mg/L, High) of indol-3-butyric acid (IBA). Using a small RNA sequencing strategy, the effect of IBA treatment on miRNAs expression was genome-widely analyzed. Results In this study, we found that wood development of poplar was promoted by low concentration of IBA treatment but inhibited by high concentration of IBA treatment. Stringent bioinformatic analysis led to identification of 118 known and 134 novel miRNAs candidates. Sixty-nine unique developmental-related miRNAs, corresponding to 269 target genes, exhibited specific expression patterns in response to auxin, as was consistent with the influence of auxin application on wood formation. Three novel miRNAs had the most number (≥ 9) of target genes, belonging to SPL, GRF and ARF gene families. The evolutionary relationships and tissue expression patterns of 41 SPL, GRF and ARF genes in poplar were thus analyzed. Of them, four representative members and corresponding miRNAs were confirmed using RT-qPCR. Conclusions Our results may be helpful for a better understanding of auxin-induced regulation of wood formation in tree species.

WTAP-mediated m6A modification of FRZB triggers the inflammatory response via the Wnt signaling pathway in osteoarthritis

An Xueying,Wang Rongliang,Lv Zhongyang,Wu Wenshu,Sun Ziying,Wu Rui,Yan Wenjin,Jiang Qing,Xu Xingquan 생화학분자생물학회 2024 Experimental and molecular medicine Vol.56 No.-

Osteoarthritis (OA) is the most common form of arthritis. However, the exact pathogenesis remains unclear. Emerging evidence shows that N6-methyladenosine (m6A) modification may have an important role in OA pathogenesis. This study aimed to investigate the role of m6A writers and the underlying mechanisms in osteoarthritic cartilage. Among m6A methyltransferases, Wilms tumor 1-associated protein (WTAP) expression most significantly differed in clinical osteoarthritic cartilage. WTAP regulated extracellular matrix (ECM) degradation, inflammation and antioxidation in human chondrocytes. Mechanistically, the m6A modification and relative downstream targets in osteoarthritic cartilage were assessed by methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing, which indicated that the expression of frizzled-related protein (FRZB), a secreted Wnt antagonist, was abnormally decreased and accompanied by high m6A modification in osteoarthritic cartilage. In vitro dysregulated WTAP had positive effects on β-catenin expression by targeting FRZB, which finally contributed to the cartilage injury phenotype in chondrocytes. Intra-articular injection of adeno-associated virus-WTAP alleviated OA progression in a mouse model, while this protective effect could be reversed by the application of a Wnt/β-catenin activator. In summary, this study revealed that WTAP-dependent RNA m6A modification contributed to Wnt/β-catenin pathway activation and OA progression through post-transcriptional regulation of FRZB mRNA, thus providing a potentially effective therapeutic strategy for OA treatment.