DC-bus capacitors take up substantial space in an electric vehicle (EV) traction inverter, limiting the traction drive’s volumetric power density. Film capacitors are typically used, but other capacitor technologies with higher energy densities can help reduce the overall size. In this article, several commercial capacitor technologies are considered for use as dc-bus capacitors for EV traction inverters. They are characterized, evaluated, and compared for optimized design for volume reduction. This article also proposes a novel capacitor packaging technique that utilizes symmetrically distant parallel capacitor branches from termination, which improves electrical and thermal performance compared to a traditional flat-printed circuit board-based design. The proposed design was prototyped for a 100-kW traction inverter, and then, the thermal and electrical characteristics were evaluated under various operating conditions. Results show that the proposed symmetrical design has 40% lower layout inductance and 80% lower temperature difference than a traditional package among the parallel capacitor branches.

中文翻译：

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电容器技术：下一代电力电子应用的表征、选择和封装


直流母线电容器占据了电动汽车 (EV) 牵引逆变器中的大量空间，限制了牵引驱动器的体积功率密度。通常使用薄膜电容器，但具有更高能量密度的其他电容器技术可以帮助减小整体尺寸。在本文中，考虑将几种商用电容器技术用作电动汽车牵引逆变器的直流母线电容器。对它们进行表征、评估和比较，以优化设计以减少体积。本文还提出了一种新颖的电容器封装技术，该技术利用来自终端的对称远距离并行电容器分支，与传统的基于平面印刷电路板的设计相比，该技术提高了电气和热性能。所提出的设计针对 100 kW 牵引逆变器进行了原型设计，然后在各种运行条件下评估了热特性和电气特性。结果表明，与并联电容器支路中的传统封装相比，所提出的对称设计的布局电感降低了 40%，温差降低了 80%。