Abstract：High-power multi-port converters can have high-frequency oscillations that seriously threaten system reliability, with the parasitic capacitance of the high-frequency transformers (HFTs) being one of the important factors. This paper summarizes the existing methods for calculating the parasitic capacitance of solid wires and litz wires and presents a piecewise solution method based on the electric field lines between solid wires to calculate the HFT parasitic capacitance. This study also corrects the shortcomings of the existing analysis method for litz wires. The analytical method for calculating the parasitic capacitance for typical C-type and Z-type winding arrangements and arbitrary multi-turn, multi-layer winding arrangements is re-derived taking into account the influence of the isolation layer in high-voltage, high-capacity transformer windings. Comparisons with finite element predictions and experimental data verify the accuracy of this method as a foundation for calculating the parasitic capacitance of HFTs for system design and analyses.
[1] 赵争鸣, 施博辰, 朱义诚. 对电力电子学的再认识:历史、现状及发展[J]. 电工技术学报, 2017, 32(12):5-15.ZHAO Z M, SHI B C, ZHU Y C. Reconsideration on power electronics:The past, present and future[J]. Transaction of China Electrotechnical Society, 2017, 32(12):5-15. (in Chinese) [2] 李子欣, 高范强, 赵聪, 等. 电力电子变压器技术研究综述[J]. 中国电机工程学报, 2018, 38(5):1274-1289.LI Z X, GAO F Q, ZHAO C, et al. Research review of power electronic transformer technologies[J]. Proceedings of the CSEE, 2018, 38(5):1274-1289. (in Chinese) [3] 王威望, 刘莹, 何杰峰, 等. 高压大容量电力电子变压器中高频变压器研究现状和发展趋势[J]. 高电压技术, 2020, 46(10):3362-3373.WANG W W, LIU Y, HE J F, et al. Research status and development of high frequency transformer used in high voltage and large capacity power electronic transformer[J]. High Voltage Engineering, 2020, 46(10):3362-3373. (in Chinese) [4] 崔彬, 李欣阳, 薛芃, 等. 双主动全桥变换器的高频振荡影响因素[J]. 清华大学学报(自然科学版), 2020, 60(6):530-536.CUI B, LI X Y, XUE P, et al. Factors influencing high frequency oscillations in dual active bridge converters[J]. Journal of Tsinghua University (Science and Technology), 2020, 60(6):530-536. (in Chinese) [5] 魏树生, 赵争鸣, 文武松, 等. 共交流母线多端口变换器高频振荡特性分析[J]. 清华大学学报(自然科学版), 2020, 60(9):751-762.WEI S S, ZHAO Z M, WEN W S, et al. Analysis of the high-frequency oscillation characteristics of a multi-port converter with an AC link[J]. Journal of Tsinghua University (Science and Technology), 2020, 60(9):751-762. (in Chinese) [6] BIELA J, KOLAR J W. Using transformer parasitics for resonant converters:A review of the calculation of the stray capacitance of transformers[J]. IEEE Transactions on Industry Applications, 2008, 44(1):223-233. [7] MASSARINI A, KAZIMIERCZUK M K. Self-capacitance of inductors[J]. IEEE Transactions on Power Electronics, 1997, 12(4):671-676. [8] DALESSANDRO L, CAVALCANTE F D S, KOLAR J W. Self-capacitance of high-voltage transformers[J]. IEEE Transactions on Power Electronics, 2007, 22(5):2081-2092. [9] LIU X, WANG Y, ZHU J, et al. Calculation of capacitance in high-frequency transformer windings[J]. IEEE Transactions on Magnetics, 2016, 52(7):1-4. [10] MARCHESAN T B, CHAGAS N B. Analytical calculation of static capacitance for high-frequency inductors and transformers[J]. IEEE Transactions on Power Electronics, 2019, 34(2):1672-1682. [11] 刘晨, 齐磊, 崔翔, 等.高压高频变压器寄生电容实验提取方法[J]. 华北电力大学学报(自然科学版), 2017, 44(1):1-8.LIU C, QI L, CUI X, el al. An experimental method for extracting parasitic capacitances of high-voltage high-frequency transformers[J]. Journal of North China Electric Power University (Natural Science Edition), 2017, 44(1):1-8. (in Chinese) [12] LIU C, QI L, CUI X, et al. Experimental extraction of parasitic capacitances for high-frequency transformers[J]. IEEE Transactions on Power Electronics, 2017, 32(6):4157-4167. [13] 杨慧娜, 柏树青. 高频变压器不同绕组结构对分布电容的影响[J]. 华北电力大学学报(自然科学版), 2014, 41(4):48-55.YANG H N, BAI S Q. Effect of the different winding strategy on distributed capacitances in high frequency transformers[J]. Journal of North China Electric Power University (Natural Science Edition), 2014, 41(4):48-55. (in Chinese) [14] 赵志英, 龚春英, 秦海鸿. 高频变压器分布电容的影响因素分析[J]. 中国电机工程学报, 2008, 28(9):55-60.ZHAO Z Y, GONG C Y, QIN H H. Effect factors on stray capacitances in high frequency transformers[J]. Proceedings of the CSEE, 2008, 28(9):55-60. (in Chinese) [15] 董纪清, 陈为, 卢增艺. 开关电源高频变压器电容效应建模与分析[J]. 中国电机工程学报, 2007, 27(31):121-126.DONG J Q, CHEN W, LU Z Y. Modeling and analysis of capacitive effects in high-frequency transformer of SMPS[J]. Proceedings of the CSEE, 2007, 27(31):121-126. (in Chinese)
2021, Vol. 61 
