Abstract：As the frequency of the switching mode power supply (SMPS) tends to be higher and the size of SMPS tends to be smaller, the electromagnetic interference (EMI), which is caused by the switching of power semiconductor device, has become more serious. The common mode (CM) noise source and CM noise propagation path of flyback converter are analyzed, then the CM noise model of converter is established. Based on the distributed capacitance model of transformer, the influence of the CM noise through the path of the ferrite core is analyzed quantitatively. A quantitative analysis method for two kinds of CM noise suppression measures, incomplete shielding layer and balanced winding, is proposed. The incomplete shielding layer can be further divided into incomplete-width and incomplete-length shielding layer for different structural parameters. The x-y axis coordinate system of the transformer is established, then the expression of electric potential distribution along winding is obtained. Based on the cancellation of common mode displacement current, the calculation method of width or length of the incomplete shielding layer and the turns of the balanced winding is given. Experimental results verify the effectiveness of proposed method and the accuracy of the calculation method.
[1] 王勤, 张杰, 阮新波, 等. 一种新型双输入反激DC/DC变换器[J]. 电工技术学报, 2011, 26(2): 115-122. Wang Qin, Zhang Jie, Ruan Xinbo, et al.A new double-input flyback DC/DC converter[J]. Transa- ction of China Electrotechnical Society, 2011, 26(2): 115-122. [2] 徐桂芝, 李晨曦, 赵军, 等. 电动汽车无线充电电磁环境安全性研究[J]. 电工技术学报, 2017, 32(22): 158-163. Xu Guizhi, Li Chenxi, Zhao Jun, et al.Electro- magnetic enrironment safety study of wireless electric vehicle charging[J]. Transaction of China Electrotechnical Society, 2017, 32(22): 158-163. [3] 贾晋, 赖志达, 王瑞妙, 等. 共模电流扫描法在汽车电子部件电磁辐射预测中的研究与应用[J]. 电工技术学报, 2018, 33(8): 1674-1684. Jia Jin, Lai Zhida, Wang Ruimiao, et al.Research and application on common-mode current scan methods to predict radiated emissions of automotive com- ponents[J]. Transactions of China Electrotechnical Socity, 2018, 33(8): 1674-1684. [4] 张凯, 方华松, 周运斌, 等. 单相全桥逆变器共模等效电路研究[J]. 电工技术学报, 2007, 22(2): 51-56. Zhang Kai, Fang Huasong, Zhou Yunbin, et al.Common-mode equivalent circuit of single-phase full-bridge inverters[J]. Transaction of China Electro- technical Society, 2007, 22(2): 51-56. [5] 金亮, 冯伟, 寇晓斐, 等. 汽车电子风扇电机控制电路与主电路电磁兼容分析与优化[J]. 电工技术学报, 2018, 33(增刊2): 270-277. Jin Liang, Feng Wei, Kou Xiaofei, et al.Analysis and optimization of electromagnetic compatibility for motor control circuit and main circuit of automobile cooling unit[J]. Transaction of China Electrotechnical Society, 2018, 33(S2): 270-277. [6] 闫琪, 李艳, 王路. 基于GaN器件的双Buck逆变器共模与损耗[J]. 电工技术学报, 2017, 32(20): 133-141. Yan Qi, Li Yan, Wang Lu.The common-mode characteristics and loss of dual Buck grid-connected inverter based on GaN devices[J]. Transactions of China Electrotechnical Society, 2017, 32(20): 133-141. [7] Kong Pengju, Wang Shuo, Lee F C, et al.Reducing common-mode noise in two-switch forward con- verter[J]. IEEE Transactions on Power Electronics, 2011, 26(5): 1522-1533. [8] Li Yiming, Zhang Huan, Wang Shuo, et al.Investigating switching transformers for common mode EMI reduction to remove common mode EMI filters and Y capacitors in flyback converters[J]. IEEE Journal of Emerging & Selected Topics in Power Electronics, 2018, 6(4): 2287-2301. [9] Tokaldani M A S, Shafiei N, Ordonez M. Planar transformers with near zero common mode noise for flyback and forward converters[J]. IEEE Transactions on Power Electronics, 2018, 33(2): 1554-1571. [10] 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 Jiqing, Chen Wei, Lu Zengyi.Modeling and analysis of capacitive effects in high-frequency transformer of SMPS[J]. Proceedings of the CSEE, 2007, 27(31): 121-126. [11] 汪泉弟, 安宗裕, 郑亚利, 等. 电动汽车开关电源电磁兼容优化设计方法[J]. 电工技术学报, 2014, 29(9): 225-231. Wang Quandi, An Zongyu, Zheng Yali, et al.Elec- tromagnetic compatibility optimization design for switching power supply used in electric vehicle[J]. Transactions of China Electrotechnical Society, 2014, 29(9): 225-231. [12] 林苏斌, 陈为, 董纪清, 等. Boost 变换器共模噪声反相补偿法的高频特性分析与改善[J]. 中国电机工程学报, 2013, 33(27): 52-59. Lin Subin, Chen Wei, Dong Jiqing, et al.High frequency behaviors analysis and improvement of antiphase compensation method for CM EMI noise suppression in Boost converters[J]. Proceedings of the CSEE, 2013, 33(27): 52-59. [13] Xie Lihong, Ruan Xinbo, Ye Zhihong.Equivalent noise source: an effective method for analyzing common-mode noise in isolated power converters[J]. IEEE Transactions on Industrial Electronics, 2016, 63(5): 2913-2924. [14] Xie Lihong, Ruan Xinbo, Ji Qing, et al.Shielding- cancelation technique for suppressing common-mode EMI in isolated power converters[J]. IEEE Transa- ctions on Industrial Electronics, 2015, 62(5): 2814-2822. [15] Fu Dianbo, Wang Shuo, Kong Pengju, et al.Novel techniques to suppress the common-mode EMI noise caused by transformer parasitic capacitances in DC- DC converters[J]. IEEE Transactions on industrial Electronics, 2013, 60(11): 4968-4977. [16] Kong Pengju, Lee F C.Transformer structure and its effects on common mode EMI noise in isolated power converters[C]//Proceedings of Applied Power Elec- tronics Conference and Exposition, Palm Springs, CA, USA, 2006: 1424-1429. [17] Xie Lihong, Ruan Xinbo, Ye Zhihong.Reducing common mode noise in phase-shifted full-bridge converter[J]. IEEE Transactions on Industrial Elec- tronics, 2018, 65(10): 7866-7877. [18] Zhang Huan, Wang Shuo, Li Yiming, et al.Two- capacitor transformer winding capacitance models for common-mode EMI noise analysis in isolated DC-DC converters[J]. IEEE Transactions on Power Elec- tronics, 2017, 32(11): 8458-8469. [19] Fei Chao, Yang Yuchen, Li Qiang, et al.Shielding technique for planar matrix transformers to suppress common-mode EMI noise and improve efficiency[J]. IEEE Transactions on Industrial Electronics, 2018, 65(2): 1263-1272. [20] Yang Yuchen, Huang Daocheng, Lee F C.et al.Transformer shielding technique for common mode noise reduction in isolated converters[C]//Energy Conversion Congress and Exposition (ECCE), Blacksburg, 2013: 4149-4153. [21] Chen Henglin, Xiao Ji.Determination of transformer shielding foil structure for suppressing common- mode noise in flyback converters[J]. IEEE Transa- ctions on Magnetics, 2016, 52(12): 1-9. [22] Zhang Huan, Yang Le, Wang Shuo, et al.Common- mode EMI noise modeling and reduction with balance technique for three-level neutral point clamped topology[J]. IEEE Transactions on Industrial Electronics, 2017, 64(9): 7563-7573. [23] Chu Yongbin, Wang Shuo.A generalized common- mode current cancelation approach for power con- verters[J]. IEEE Transactions on Industrial Elec- tronics, 2015, 62(7): 4130-4140. [24] 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. [25] 董纪清, 陈晓威, 林苏斌. 考虑漏磁特性的变压器电磁干扰特性模型[J]. 电工技术学报, 2017, 32(21): 63-72. Dong Jiqing, Chen Xiaowei, Lin Subin.Electro- magnetic interference model of transformer con- sidering the leakage magnetic field[J]. Transactions of China Electrotechnical Society, 2017, 32(21): 63-72.
2019, Vol. 34 
