In this paper, new optimal procedures are introduced to design the finest controllers and harmonic compensators (HCs) of three-level cascaded control for three-phase grid-supporting inverters based-AC microgrid. The three control levels, comprising primary, secondary and synchronization control levels, are developed in stationary -frame and based on the proportional–integral (PI) controllers and the proportional-resonant controllers along with additional HCs. The new optimal design guidelines of microgrid’s controllers and HCs are aimed to fulfill the study requirements. The optimization objectives and constraints are employed to minimize both the total harmonic distortion (THD) and individual harmonics of microgrid’s voltage to enhance the quality of microgrid’s output power. The THD of microgrid’s voltage can be reduced to 0.19% under the nonlinear loads. Moreover, the microgrid’s voltage and frequency can be perfectly regulated with zero deviations. Furthermore, these new optimal procedures accelerate the speed of synchronization process between the external power grid and the microgrid to be accomplished in time less than 20 ms. Additionally, an accurate power-sharing among paralleled operated inverters can be achieved to avoid overstressing on any one. Also, seamless transitions can be guaranteed between grid-tied and isolated operation mode. The optimal controllers and HCs are designed by a new optimization algorithm called H-HHOPSO, which is created by hybridizing between Harris hawks optimization and particle swarm optimization algorithms. The effectiveness and robustness of the H-HHOPSO-based controllers and HCs are compared with other meta-heuristic optimization algorithms-based controllers and HCs. A microgrid, including two grid-supporting inverters based optimal controllers and optimal HCs, are modeled and carried out using MATLAB/SIMULINK to test the performance under linear and nonlinear loads, and also during the interruption of any one of two inverters. The performance is investigated according to IEC/IEEE harmonic standards, and compared with the conventional control strategy developed in synchronous -frame and based on only PI controllers.

中文翻译：

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基于逆变器的交流微电网静止参考系三电平串级控制控制器和谐波补偿器的优化设计

本文介绍了新的优化程序来设计基于交流微电网的三相并网逆变器的三电平级联控制的最佳控制器和谐波补偿器（HC）。三个控制级别，包括初级、次级和同步控制级别，是在固定框架中开发的，并基于比例积分 (PI) 控制器和比例谐振控制器以及附加 HC。新的微电网控制器和HC优化设计指南旨在满足研究要求。采用优化目标和约束来最小化微电网电压的总谐波失真（THD）和单个谐波，以提高微电网输出功率的质量。非线性负载下微电网电压THD可降低至0.19%。而且微电网的电压和频率可以完美调节，零偏差。此外，这些新的优化程序加快了外部电网和微电网之间的同步过程的速度，在不到20毫秒的时间内完成。此外，可以在并联运行的逆变器之间实现精确的功率共享，以避免任何一个逆变器承受过大的压力。此外，还可以保证并网和孤立运行模式之间的无缝过渡。最优控制器和 HC 是通过一种名为 H-HHOPSO 的新优化算法设计的，该算法是通过混合 Harris hawks 优化和粒子群优化算法创建的。基于 H-HHOPSO 的控制器和 HC 的有效性和鲁棒性与其他基于元启发式优化算法的控制器和 HC 进行了比较。使用 MATLAB/SIMULINK 对微电网（包括两个基于最优控制器和最优 HC 的并网逆变器）进行建模和执行，以测试线性和非线性负载下以及两个逆变器中任何一个逆变器中断期间的性能。根据 IEC/IEEE 谐波标准对性能进行了研究，并与同步框架中开发的仅基于 PI 控制器的传统控制策略进行了比较。