The increasing number of nonlinear loads and the integration of renewable energy sources into the grid make the conventional SRF-PLL less accurate for estimating the phase and frequency of the grid voltage. A variety of enhanced filtering-based PLLs have been reported in the literature to solve this issue. However, these techniques are computationally more complex. For this reason, a method has been proposed to improve the performance of low pass filter (LPF)-based SRF-PLL, which is easy to implement and is computationally less expensive. In this paper, two in-loop second-order notch filters have been used with an LPF to nullify the effect of dominant lower order harmonics. The dynamic performance of the proposed technique is improved by implementing a PID type loop filter. The proposed scheme is compared with the other methods, like MRF-PLL, conventional and LPF-based SRF-PLL. The response of the proposed PLL is found to be encouraging under different grid disturbances. The efficacy of the proposed PLL has been verified by implementing the current controller to control the active and reactive grid current for the grid side converter in the hardware setup.

非线性负载数量的增加以及可再生能源并网的增加，使得传统的 SRF-PLL 在估计电网电压的相位和频率方面不太准确。文献中已经报道了多种基于增强滤波的 PLL 来解决这个问题。然而，这些技术在计算上更加复杂。出于这个原因，已经提出了一种方法来提高基于低通滤波器 (LPF) 的 SRF-PLL 的性能，该方法易于实现且计算成本较低。在本文中，两个环内二阶陷波滤波器与 LPF 一起使用，以消除主要低阶谐波的影响。所提出的技术的动态性能通过实施 PID 型环路滤波器得到改善。所提出的方案与其他方法（如 MRF-PLL）进行了比较，传统和基于 LPF 的 SRF-PLL。发现所提出的 PLL 的响应在不同的电网扰动下令人鼓舞。通过在硬件设置中实现电流控制器来控制电网侧转换器的有功和无功电网电流，已验证了所提出的 PLL 的功效。