Parallel operation of grid-interactive inverters has been continuously gaining attraction, and their contribution to sustaining the host grid stability has become strongly demanded. This paper investigates and discusses the trends in the most recent interconnection grid codes. Grid codes call for simultaneous requirements for the low-voltage ride-through capabilities of parallel operation of grid-interactive inverters as well as their effective asymmetrical voltage support by advanced active/reactive bi-sequence power provision under unbalanced grid faults. Addressing these demands in an optimized way becomes very challenging. This paper thus proposes a new methodology to simultaneously achieve three main objectives: (1) coordination of the asymmetrical ride-through and voltage support capabilities of parallel-operated inverters, (2) maximizing the utilization of each unit and their collective contribution in boosting the positive-sequence voltage and reduction of the negative sequence voltage subject to the constraints from the inverters and the grid, and (3) minimizing the impact of the support on the active power injections. Simulation and experimental results illustrate the effectiveness of the proposed algorithm.

中文翻译：

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并联运行的电网交互式智能逆变器的最大不对称支持


并网互动逆变器的并联运行不断受到关注，人们强烈要求它们在维持主电网稳定性方面做出贡献。本文调查并讨论了最新互连电网规范的趋势。电网规范要求同时要求并网互动逆变器并联运行的低电压穿越能力以及在不平衡电网故障下通过先进的有功/无功双序供电提供有效的不对称电压支持。以优化的方式满足这些需求变得非常具有挑战性。因此，本文提出了一种新方法，可同时实现三个主要目标：（1）协调并联逆变器的不对称穿越和电压支持能力，（2）最大化每个单元的利用率及其在提高发电量方面的集体贡献。正序电压和负序电压的降低受到逆变器和电网的约束；（3）最小化支持对有功注入的影响。仿真和实验结果说明了该算法的有效性。