Optimal Design and Common-Mode Electromagnetic Interference Noise Suppression for High Turn-Ratio Planar Magnetic Integration Transformer
Guo Jing1, Wang Hui1, Huang Yuanxin2, Xu Guo1, Han Hua1
1. Hunan Provincial Key Laboratory of Power Electronics Equipment and Grid Central South University Changsha 410083 China; 2. Changsha Institute of Mining Research Co. Ltd Changsha 410012 China
Abstract：High voltage-gain-range bidirectional DC-DC converters with high efficiency, high power density, and high reliability are vital for industrial applications. The transformer of such converters often has a high turn ratio. Due to multiple magnetic components, their volume proportion and losses are high. Therefore, the converter's power density and operational efficiency are affected. Magnetic component design based on printed circuit boards（PCBs）has been widely used in isolated bidirectional DC-DC converters due to its simple winding layout, low magnetic component losses, and low-profile design. However, for high-turn-ratio transformers, the large PCB copper area on the low-voltage side winding increases the parasitic capacitance between the primary and secondary windings of the isolation transformer, providing a coupling path for common-mode（CM）noise and causing severe electromagnetic interference（EMI). Therefore, the converter's electromagnetic compatibility（EMC）characteristics are affected. From the perspective of reducing the number of magnetic components, the magnetizing inductance can be easily incorporated into the transformer by adjusting the air gap, whereas the leakage inductance is typically designed separately. Using asymmetrically distributed windings, the air-gap magnetic resistance of the center core leg can be adjusted to generate controllable leakage inductance. However, with Litz wire, the winding structure becomes more complex because the windings are wound on both outer core legs. From the perspective of CM EMI noise suppression, adding an EMI filter at the converter input is a widely used approach. The CM choke coil effectively suppresses CM noise. However, the additional magnetic components affect the system's operating efficiency and power density. For PCB winding transformers with a turn ratio of 1, a winding-cancellation technique can minimize displacement current between the primary and secondary windings by configuring the windings to have equal potential. However, for high-turn-ratio transformers, the influence of each winding's potential distribution on the winding-cancellation design requires further analysis, and the layout of the cancellation windings under high-turn-ratio conditions has not yet been studied. This paper proposes a magnetic-integrated method for a symmetrical planar transformer based on the static electric potential（SEP）point construction. Based on the integration of magnetizing inductance, leakage inductance, and high-turn-ratio transformers, the winding cancellation technology is applied to design common-mode shielding for high-turn-ratio planar magnetic integrated transformers. Consequently, the system power density is effectively increased, CM EMI noise is suppressed, and the system EMC characteristics are improved. In addition, through the optimized design of symmetrical plane-integrated magnetic components, the number of symmetrical magnetic cores is determined to achieve the lowest system loss, an equal air-gap structure, and magnetic component size parameters, which improved system operating efficiency.
[1] 倪硕, 吴红飞, 陈君雨, 等. 交错并联临界导通模式Buck电感高密度集成与优化[J]. 电工技术学报, 2022, 37(18): 4688-4696. Ni Shuo, Wu Hongfei, Chen Junyu, et al.Integration and optimization of a high power density inductor for an interleaved critical conduction mode Buck con-verter[J]. Transactions of China Electrotechnical Society, 2022, 37(18): 4688-4696. [2] 李洪珠, 陈星星, 李超, 等. 带倍压单元的有源开关电感高增益变换器及其磁集成[J]. 电工技术学报, 2025, 40(7): 2191-2202. Li Hongzhu, Chen Xingxing, Li Chao, et al.Active switched inductor high step-up converter with voltage multiplier cell and magnetic integration[J]. Trans-actions of China Electrotechnical Society, 2025, 40(7): 2191-2202. [3] 管乐诗, 温兆亮, 许晓志, 等. 适用于宽增益范围的可重构单级DC-DC 变换器及其磁元件设计[J]. 电工技术学报, 2023, 38(6): 1571-1583. Guan Yueshi, Wen Zhaoliang, Xu Xiaozhi, et al.A modular reconfigurable single-stage DC-DC converter suitable for wide gain range and its magnetic design[J]. Transactions of China Electrotechnical Society, 2023, 38(6): 1571-1583. [4] 朱一昕, 张威, 刘淳铭, 等. 基于平面磁集成变压器的高位取能电源设计[J/OL]. 电源学报, 1-18[2025-12-05]. https://link.cnki.net/urlid/12.1420.TM.20250326.1604.010. Zhu Yixin, Zhang Wei, Liu Chunming, et al. Design of high-voltage power supply based on planar magnetic integrated transformer[J/OL]. Journal of Power Supply, 1-18[2025-12-05]. https://link.cnki.net/urlid/12.1420.TM.20250326.1604.010. [5] 谢昌桦, 张丽萍, 陈为, 等. 多相交错并联耦合电感的分析与设计[J]. 电源学报, 2025, 23(2): 31-39. Xie Changhua, Zhang Liping, Chen Wei, et al.Analysis and design of multi-phase interleaved parallel coupled inductors[J]. Journal of Power Supply, 2025, 23(2): 31-39. [6] Cao Yuliang, Fan Boran, Bai Yijie, et al.Common-mode noise reduction and capacitor voltage auto-balance using bridged midpoints and coupled inductor in a 3-L Buck-Boost converter[J]. IEEE Transactions on Power Electronics, 2023, 38(10): 12365-12369. [7] Fu Minfan, Fei Chao, Yang Yuchen, et al.Optimal design of planar magnetic components for a two-stage GaN-based DC-DC converter[J]. IEEE Transactions on Power Electronics, 2019, 34(4): 3329-3338. [8] 刘开元, 沈湛, 陈武, 等. 一种分布式气隙磁集成结构及其漏感精确建模[J]. 中国电机工程学报, 2025, 45(13): 5255-5271. Liu Kaiyuan, Shen Zhan, Chen Wu, et al.A distributed air gap magnetic integrated structure and accurate modelling of leakage inductance[J]. Pro-ceedings of the CSEE, 2025, 45(13): 5255-5271. [9] Zhang Jun, Ouyang Ziwei, Duffy M C, et al.Leakage inductance calculation for planar transformers with a magnetic shunt[C]//2013 IEEE Energy Conversion Congress and Exposition, Denver, CO, USA, 2013: 643-648. [10] Mu M, Xue L, Boroyevich D, et al.Design of integrated transformer and inductor for high frequ-ency dual active bridge GaN charge for PHEV[C]//Proceedings of 2015 IEEE Applied Power Electronics Conference and Exposition, Charlotte, NC, USA, 2015, 579-585. [11] Li Bin, Li Qiang, Lee F C.High-frequency PCB winding transformer with integrated inductors for a bi-directional resonant converter[J]. IEEE Transac-tions on Power Electronics, 2019, 34(7): 6123-6135. [12] Phukan R, Zhao Xingchen, Chang Chewei, et al.Enhanced three-phase AC common-mode filter with optimized damping network for VFDs[J]. IEEE Transactions on Industry Applications, 2023, 59(4): 4274-4286. [13] 江师齐, 王卫, 王盼宝, 等. 一种结构对称型电磁集成电磁干扰滤波器分析与设计[J]. 电工技术学报, 2022, 37(22): 5826-5835. Jiang Shiqi, Wang Wei, Wang Panbao, et al.Analysis and prototyping of the electromagnetic integration of a structure-symmetrical electromagnetic interference filter[J]. Transactions of China Electrotechnical Society, 2022, 37(22): 5826-5835. [14] Guo Jing, Wang Hui, Xu Guo, et al.Dual coupled inductors with controllable integrated leakage indu-ctance and CM noise suppression for CF-DAB converter[J]. IEEE Transactions on Power Electronics, 2023, 38(7): 8033-8038. [15] 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. [16] Nabih A, Jin Feng, Li Qiang.Efficient integrated transformer-inductor with high PCB utilization and optimized core[J]. IEEE Transactions on Industrial Electronics, 2024, 71(6): 5653-5662. [17] Le K D, Nguyen Q H, Nguyen M Q, et al.Novel shielding method for planar transformers to suppress common-mode EMI noise and improve soft-switching range[J]. IEEE Transactions on Industrial Electronics, 2025, 72(9): 9095-9105. [18] Ge Zixian, Wu Hongfei, Liu Yue.Low-loss segmented shielding technique for PCB-winding planar transformers[J]. IEEE Transactions on Power Electronics, 2023, 38(1): 12-16. [19] He Binghui, Chen Yang, Yu Xiang, et al.Com-plementary couple-turns: an effective method for reducing common-mode noise in full-bridge LLC resonant converter with split primary winding transformer[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2024, 12(3): 2882-2901. [20] Jin Feng, Yuan Tianlong, Nabih A, et al.Efficient integrated magnetics with winding cancellation technique to reduce common-mode EMI noise for a single-phase CLLC converter[J]. IEEE Transactions on Power Electronics, 2024, 39(11): 14758-14774. [21] Hurley W G, Gath E, Breslin J G.Optimizing the AC resistance of multilayer transformer windings with arbitrary current waveforms[J]. IEEE Transactions on Power Electronics, 2000, 15(2): 369-376. [22] 程鹤, 徐恺, 李朋圣, 等. 三相CLLC谐振变换器磁集成平面变压器设计与优化[J]. 电工技术学报, 2024, 39(12): 3774-3786. Cheng He, Xu Kai, Li Pengsheng, et al.Design and optimization of three-phase CLLC resonant converter with magnetic integrated planar trans-former[J]. Transactions of China Electrotechnical Society, 2024, 39(12): 3774-3786. [23] Advanced Energy Co., Ltd. Aif 300 V vin series datasheet[EB/OL].（2024)[2025-09-03]. https://www.advancedenergy.com. [24] TDK-Lambda Co., Ltd. Ph1200a280 series data-sheet[EB/OL].（2024-01-11)[2025-09-03]. https://www.lambda.tdk.com.cn. [25] 金升阳公司. Vrf3d_fb-1200wr3系列数据手册[EB/OL].（2023-10-17)[2025-09-03]. https://www.mornsun.cn/html. Mornsun Co., Ltd. Vrf3d_fb-1200wr3 series data-sheet[EB/OL].（2023-10-17)[2025-09-03]. https://www.mornsun.cn/html. [26] Vicor Co., Ltd. Dcm5614xd0h36k3yzz series data-sheet[EB/OL].（2023-06)[2025-09-03]. https://www.vicorpower.com.
2026, Vol. 41 
