In this paper, an active electromagnetic interference (EMI) choke for both common-mode (CM) and differential-mode (DM) noise suppression is proposed. Three isolated windings with a different number of turns are wound on the same magnetic core. One of the windings is served as the auxiliary winding connecting to an active circuit called the negative impedance circuit. The inductance of the EMI choke is substantially boosted up to effectively attenuate the low-frequency noise. This technique leads to a greater inductance but fewer turns and smaller size of the EMI choke. Different from the design of a conventional EMI filter, which uses separated CM and DM chokes, this proposal saves the cost and space of the EMI filter. The enhancement to the CM and DM impedance is individually analyzed and experimentally confirmed. Based on the classical CM and DM noise models, CM and DM noise insertion losses are predicted using computer simulation. The simulation results are validated by a network impedance analyzer. Finally, conducted EMI tests are carried out to verify the effectiveness of the proposed technique.

中文翻译：

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用于共模和差模噪声抑制的有源 EMI 扼流圈

在本文中，提出了一种用于共模 (CM) 和差模 (DM) 噪声抑制的有源电磁干扰 (EMI) 扼流圈。三个不同匝数的隔离绕组绕在同一个磁芯上。其中一个绕组用作连接到称为负阻抗电路的有源电路的辅助绕组。EMI 扼流圈的电感大幅提升，以有效衰减低频噪声。这种技术导致更大的电感但更少的匝数和更小的 EMI 扼流圈尺寸。与传统的 EMI 滤波器设计不同，它使用分离的 CM 和 DM 扼流圈，该方案节省了 EMI 滤波器的成本和空间。对 CM 和 DM 阻抗的增强分别进行了分析和实验证实。基于经典的 CM 和 DM 噪声模型，使用计算机模拟来预测 CM 和 DM 噪声插入损耗。仿真结果由网络阻抗分析仪验证。最后，进行传导 EMI 测试以验证所提出技术的有效性。