适用于微网并网控制技术的改进型EPLL算法研究

快速准确的锁相环技术是保证并网系统安全、可靠并网的关键。针对传统EPLL的固有缺陷，设计了一种改进型EPLL算法，适用于以分布式电源为主的微网并网控制技术。首先，推导出输出电压频率和输入电压幅值之间的耦合关系，使用数学公式进行近似解耦。其次，搭建误差信号的成本函数，利用梯度下降法设计直流偏移量的估算环路，通过闭环负反馈回路消去输入信号中的直流偏置。然后，在锁相算法的所有估算环路中引入滑动平均值滤波器（moving average filter，MAF），以增强控制系统的高频谐波抗干扰能力。最后，在Matlab/Simulink软件中搭建了单相锁相环算法的仿真模型，进行对比分析。仿真结果验证了所提算法的正确性和可行性。

Research on Improved EPLL Algorithm Suitable for Grid-connected Control Technology for Microgrid

Fast and accurate PLL technology is the key to ensure the safety and reliability of grid connected system. In view of the inherent defects of tra-ditional EPLL, an improved EPLL algorithm is designed, which is suitable for the micro grid connection control technology based on distributed power supply. Firstly, the coupling relationship between the output voltage frequency and the input voltage amplitude is derived, and the ap-proximate decoupling is carried out by using mathematical formula. Secondly, the cost function of the error signal is constructed, and the DC offset estimation loop is designed by gradient descent method, and the DC offset in the input signal is eliminated by the closed-loop negative feedback loop. Then, the moving average filter (MAF) is introduced into all estimation loops of the phase-locked algorithm to enhance the an-ti-interference ability of the control system. Finally, the simulation models of single-phase PLL algorithms are built in Matlab/Simulink software for comparative analysis. The simulation results verify the correctness and feasibility of the proposed algorithm.