Input-series-output-parallel (ISOP) inverter system is very suitable for high dc input voltage and large ac output current power conversion applications. If this topology is applied to the grid-connected occasion, a bulky-capacity grid-connected inverter can be built with multiple small-capacity standardized inverter modules, which can significantly improve the reliability of the system operation and facilitate system design. In this paper, we investigate an ISOP LCL-type grid-connected inverter system, and put forward an optimized way for the topology of combined LCL filters first. Then, the inverter-side inductor current is carefully chosen as the controlled variable and thus a concise distributed control method is proposed to achieve multiple control objectives. On the basis of the presented distributed control, the redundant control technique is also provided to heighten the reliability of the grid-tied ISOP inverter indeed. Finally, a three-module prototype is built and the experimental results validate the effectiveness of the raised strategy.

中文翻译：

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输入-串联-输出-并联LCL型并网逆变器系统实现多目标和高可靠性的控制方案

输入串联输出并联 (ISOP) 逆变器系统非常适合高直流输入电压和大交流输出电流的功率转换应用。如果将该拓扑应用于并网场合，可以用多个小容量标准化逆变模块构建一个大容量并网逆变器，可以显着提高系统运行的可靠性，方便系统设计。在本文中，我们研究了 ISOP LCL 型并网逆变器系统，并首先提出了组合 LCL 滤波器拓扑结构的优化方法。然后，仔细选择逆变器侧电感电流作为控制变量，从而提出一种简洁的分布式控制方法来实现多个控制目标。在提出的分布式控制的基础上，还提供了冗余控制技术，确实提高了并网ISOP逆变器的可靠性。最后，构建了一个三模块原型，实验结果验证了所提出策略的有效性。