For power electronic converter systems, the cost and the size of the magnetic components are typically limiting factors when it comes to overall production costs and power density. This especially holds for soft-switching high-frequency applications, where a resonant discharge of the output capacitances of the semiconductors relies on sufficient amount of energy stored in the main magnetic components, i.e., inductors or transformers, yielding a substantial increase in their volumes. In this article, an alternative solution is introduced, where a small auxiliary circuit is used to ensure soft-switching of the power transistors, whereby the aforementioned volume of the main magnetic components can be significantly reduced. The proposed auxiliary circuit provides zero-voltage-switching conditions independent of the applied voltages, the switching frequency, and the output power level, without significantly increasing the circuit complexity or the control effort. The new concept is first analyzed based on simple analytical calculations and circuit simulations, and is then experimentally verified by means of hardware demonstrators related to a 3.6-kW 250–500V/250–500V series-resonant dc/dc converter application. Finally, it is shown that the auxiliary circuit can also be used to precharge the output capacitor of a converter system, which allows to further reduce the size of the main magnetic components.

中文翻译：

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零电压开关辅助电路，可将串联谐振DC / DC转换器系统中的电感要求降至最低

对于电力电子转换器系统，在总体生产成本和功率密度方面，磁性部件的成本和尺寸通常是限制因素。对于软开关高频应用尤其如此，其中半导体的输出电容的谐振放电依赖于存储在主要磁性组件（即电感器或变压器）中的足够量的能量，从而导致其体积显着增加。在本文中，介绍了一种替代解决方案，其中使用了一个小的辅助电路来确保功率晶体管的软开关，从而可以显着减小上述主要磁性元件的体积。拟议的辅助电路提供了零电压切换条件，与施加的电压无关，开关频率和输出功率水平，而不会显着增加电路复杂性或控制工作量。首先根据简单的分析计算和电路仿真对新概念进行分析，然后通过与3.6kW 250–500V / 250–500V串联谐振dc / dc转换器应用相关的硬件演示器，对新概念进行实验验证。最后，示出了辅助电路也可以用于对转换器系统的输出电容器进行预充电，这允许进一步减小主要磁性部件的尺寸。然后通过与3.6 kW 250-500V / 250-500V串联谐振DC / DC转换器应用相关的硬件演示器进行实验验证。最后，示出了辅助电路也可以用于对转换器系统的输出电容器进行预充电，这允许进一步减小主要磁性部件的尺寸。然后通过与3.6 kW 250-500V / 250-500V串联谐振DC / DC转换器应用相关的硬件演示器进行实验验证。最后，示出了辅助电路也可以用于对转换器系统的输出电容器进行预充电，这允许进一步减小主要磁性部件的尺寸。