Affiliations: [a] School of Mathematics and Statistics, Southwest University, Chongqing, China | [b] Vehicle Engineering Institute, Chongqing University of Technology, Chongqing, China | [c] Chongqing Qingyan Ligong Electronic Technology Co., Ltd, Chongqing, China | [d] School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, China
Correspondence:
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Corresponding authors: X. Wu, Chongqing Qingyan Ligong Electronic Technology Co., Ltd, Chongqing 401329, China. E-mail: wxs_bernice@163.com and Y. Chen, School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China. E-mail: ychencd@uestc.edu.cn
Abstract: Due to the high voltage and high current working characteristics of EV driving system, strong electromagnetic interference is formed in the working process, and the shielding effectiveness of the high-voltage connector assembly connecting each part of the driving system is directly related to the level of its electromagnetic interference emission. The high-voltage connector is usually made by triaxial method. However, due to the influence of sample coupling length and cutoff frequency, the triaxial method is prone to produce a region of more than 25 MHz, resulting in test failure. Therefore, modeling analysis of the shielding effectiveness of the connector assembly in the early stage is crucial for the final development of a connector assembly with good shielding effectiveness. In this paper, an analytical optimization model named ZTD-Demoulin is proposed to calculate the transfer impedance value of the dynamic shielded wire (double-layer shielded) of the electric vehicle. The model takes into account the influence of the double-layer shielded cable (braided-belt and aluminum foil) on the DC resistance and small-hole inductance of the shielding layer, and analyzes the transfer impedance value which presents the shielding effectiveness of the connector assembly. Based on the double-layer shield optimization model, an optimization model of high-voltage connector assembly is established. This established model takes into account the influence of connector contact resistance and inductance value. Comparison between the triaxial coaxial method and the established model found that when Kconnector = 6Kcable, the fitting effect of the model was the best and the transfer impedance value above 25 MHz could be predicted.
Keywords: Power cable, transfer impedance, triaxial method, double layer shielding
