Abstract This paper proposes the estimation of parameters and symmetrical components of unbalanced grid using adaptive observer framework. Recent adaptive observers proposed in the literature doesn’t employ any gain normalization in their frequency estimation loop. This can be problematic in the presence of large voltage dip. This paper proposes a solution to overcome this limitation using a novel gain normalized - frequency-locked loop (GN-FLL). Technical details of GN-FLL, stability analysis and tuning are provided in this paper. Comparative experimental results with adaptive Luenberger observer, second-order generalized integrator - phase-locked loop (SOGI-PLL) and enhanced PLL (EPLL) are provided to demonstrate the effectiveness the proposed technique in the single-phase case. Comparative experimental results with double SOGI-FLL (DSOGI-FLL) and adaptive notch filter (ANF) are provided to demonstrate the effectiveness the proposed technique in the three-phase case.

中文翻译：

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三相系统增益归一化自适应观测器

摘要 本文提出了使用自适应观测器框架估计不平衡电网参数和对称分量的方法。最近在文献中提出的自适应观测器在其频率估计循环中没有采用任何增益归一化。这在存在大电压骤降的情况下可能会出现问题。本文提出了一种使用新型增益归一化锁频环 (GN-FLL) 来克服此限制的解决方案。本文提供了 GN-FLL 的技术细节、稳定性分析和调整。提供了自适应 Luenberger 观测器、二阶广义积分器 - 锁相环 (SOGI-PLL) 和增强型 PLL (EPLL) 的比较实验结果，以证明所提出的技术在单相情况下的有效性。