In this study, an advanced phase-locked-loop (PLL), which has a simple structure and a low computational burden is proposed. The proposed PLL also improves the dynamic performance and the filtering capability of the conventional three-phase enhanced-PLL (3pEPLL) significantly. The conventional 3pEPLL operates three individual EPLL blocks for each phase voltage and a fourth EPLL for estimation of the magnitude, frequency, and phase angle, which considerably increases the structural complexity and computational burden. However, the proposed PLL called enhanced-3pEPLL (E ² PLL) employs only two single-phase EPLL modules in its pre-filtering stage. A moving-average-filter (MAF) is also supplemented on the error signal path of these EPLL modules, which allows smoother estimation of the magnitude, frequency, and phase angle, and improves the filtering capability of the EPLLs. Unlike the conventional 3pEPLL, the proposed E ² PLL employs a quasi-type-1 PLL (QT1-PLL) to estimate the magnitude, frequency, and phase information of the fundamental grid voltage. The structure of QT1-PLL is similar to a type-1 PLL, which offers a low transient response time. The small-signal model of the proposed PLL is derived for stability analysis and parameter design procedure. The effectiveness of the E ² PLL is verified owing to experimental results and comparison with the conventional 3pEPLL and QT1-PLL.

中文翻译：

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非理想电网条件下三相EPLL的高效实现和性能改进

在这项研究中，提出了一种结构简单，计算负担低的高级锁相环（PLL）。所提出的PLL还显着改善了常规三相增强型PLL（3pEPLL）的动态性能和滤波能力。常规的3pEPLL为每个相电压操作三个独立的EPLL块，并为估计幅度，频率和相角而操作第四个EPLL，这大大增加了结构复杂性和计算负担。但是，建议的PLL称为增强型3pEPLL（E ² PLL）在其预滤波阶段仅采用两个单相EPLL模块。在这些EPLL模块的误差信号路径上还添加了移动平均滤波器（MAF），从而可以更平滑地估计幅度，频率和相位角，并提高EPLL的滤波能力。与传统的3pEPLL不同，建议的E ² PLL采用准1型PLL（QT1-PLL）来估算基本电网电压的大小，频率和相位信息。QT1-PLL的结构类似于Type-1 PLL，它具有很短的瞬态响应时间。推导了所提出的PLL的小信号模型，用于稳定性分析和参数设计程序。E ²的有效性 根据实验结果验证了PLL，并将其与常规3pEPLL和QT1-PLL进行了比较。