The bidirectional power flow in most of the existing four-port converters is achieved on the battery port located on the low voltage side, i.e., the battery is charged by the energy sources and discharged to the dc link on the high voltage side. The lack of the bidirectional power flow at the dc link prevents them from managing the power at the system level. In this article, a bidirectional four-port dc–dc converter is proposed for the integration of the hybrid renewable energy system to a dc microgrid. The proposed converter uses the least number of devices compared with the existing bidirectional multiport converters. The bidirectional battery and the dc-link ports make it a good candidate for the dc-microgrid application in which the system-level power management is desired. The working principle of the converter is first analyzed, and the power transferred by the transformer and the zero-voltage switching (ZVS) conditions are derived. Then, the converter is designed to meet the requirements of the power rating and soft switching. The proposed converter is used to interface a wind turbine, a photovoltaic panel, a battery bank, and the dc microgrid. The experiments are carried to testify the performance in both steady state and the transient. The steady-state waveforms have validated the power relationship as well as the critical ZVS conditions while maintaining relatively high efficiency. The transient testing results show that the converter can switch from one scenario to another under the different conditions. This article is accompanied by a video demonstrating the converter in the real-time operation.

中文翻译：

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用于混合可再生能源系统集成的多端口双向 DC-DC 转换器

大多数现有四端口转换器中的双向功率流是在位于低压侧的电池端口上实现的，即电池由能源充电并放电到高压侧的直流链路。直流链路上缺乏双向功率流会阻止他们在系统级管理功率。在本文中，提出了一种双向四端口 DC-DC 转换器，用于将混合可再生能源系统集成到直流微电网。与现有的双向多端口转换器相比，所提出的转换器使用最少数量的设备。双向电池和直流链路端口使其成为需要系统级电源管理的直流微电网应用的理想选择。首先分析转换器的工作原理，并推导出变压器传输的功率和零电压开关 (ZVS) 条件。然后，设计转换器以满足额定功率和软开关的要求。所提出的转换器用于连接风力涡轮机、光伏面板、电池组和直流微电网。进行实验以验证稳态和瞬态下的性能。稳态波形验证了功率关系以及临界 ZVS 条件，同时保持了相对较高的效率。瞬态测试结果表明，转换器可以在不同条件下从一种场景切换到另一种场景。本文附有演示转换器实时操作的视频。