Nonfrequency-dependent transport delay phase-locked loop (NTD-PLL) comprised of an additional transport-delay (TD) unit in the Park transformation matrix (TM), supposedly to improve the offset and double-frequency oscillatory errors (DFOEs) during the frequency deviations. This modification in the Park TM, however, does not eliminate the DFOEs from all the estimation parameters of the utility grid. It is shown in this letter that the issue can be completely alleviated from all the estimation parameters of the grid just by adding another TD unit in the Park TM of NTD-PLL. The effectiveness of the suggested approach is verified through numerical and experimental results.

中文翻译：

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真正基于 NTD 的 PLL：双频振荡抑制的简单方法


非频率相关传输延迟锁相环 (NTD-PLL) 由 Park 变换矩阵 (TM) 中的附加传输延迟 (TD) 单元组成，据说可以改善传输期间的偏移和双频振荡误差 (DFOE)频率偏差。然而，Park TM 中的这种修改并没有从公用电网的所有估计参数中消除 DFOE。这封信表明，只需在NTD-PLL的Park TM中添加另一个TD单元，就可以从电网的所有估计参数中完全缓解该问题。通过数值和实验结果验证了所建议方法的有效性。