Abstract This paper presents a novel seamless transfer strategy for microgrids (MGs) that enables both grid-connected and islanding modes, with no need of forced controller switching between different controllers and with improved performance in both reference tracking and disturbance attenuation. A unified control structure based on droop technique is utilized to generate the voltage and frequency references, accommodating all operation modes. Alternatively, the dynamical feedforward with reference model control and disturbance observer are introduced into the cascaded voltage-current control, which not only estimates and compensates the influences of power fluctuation as well as model uncertainties timely, but also provides the perfect reference tracking capability. Then the detailed analysis on the deduced mathematical model of inverter is carried out, and the superiority of the proposed strategy is demonstrated in tracking performance, disturbance attenuation and robustness. Simulation and experimental results show that the harmful transients during the operation mode transition can be effectively eliminated with the overall dynamic performance improved so that the effectiveness of the proposed control scheme is verified.

中文翻译：

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基于扰动观测器的微电网无缝转移控制策略

摘要 本文提出了一种新颖的微电网（MG）无缝转移策略，该策略支持并网和孤岛模式，无需在不同控制器之间强制控制器切换，并且在参考跟踪和干扰衰减方面都具有改进的性能。基于下垂技术的统一控制结构用于生成电压和频率参考，适用于所有操作模式。或者，在级联电压-电流控制中引入带有参考模型控制和扰动观测器的动态前馈，不仅可以及时估计和补偿功率波动和模型不确定性的影响，还提供完善的参考跟踪能力。然后对推导出的逆变器数学模型进行了详细分析，证明了所提出的策略在跟踪性能、扰动衰减和鲁棒性方面的优越性。仿真和实验结果表明，可以有效地消除运行模式转换过程中的有害瞬态，提高整体动态性能，从而验证了所提出控制方案的有效性。