基于改进型二阶广义积分器的单相锁相环设计

Design of Single-Phase Phase-Locked Loop Based on Improved Second-Order Generalized Integrator

针对传统基于二阶广义积分器的锁相环(SOGI-PLL)存在谐波抑制能力差、抗直流干扰能力不强的问题,提出了一种基于改进型SOGI的新型锁相环结构。该结构将两个SOGI模块串联,可以很好地消除电网存在的谐波分量以及直流干扰。针对传统的锁相环结构在面临电网频率波动时,无法对其进行自适应跟踪这一不足,采用了过零检测的方法来获得电网的实时频率,并将其直接馈送至改进的SOGI结构的谐振频率处,有效地提高了锁相环的频率自适应能力。仿真和试验结果均表明,所设计的改进型二阶广义积分器的锁相环具有锁相精度高、动态性能好的优点,对单相光伏并网技术的实现具有很好的参考价值。

A novel phase-locked loop(PLL)based on improved second-order generalized integrator(SOGI)was proposed to solve the problems of poor harmonic suppression and weak dc interference resistance of traditional SOGI-PLL.The structure connected two SOGI modules in series,which can eliminate the harmonic component and dc interference in the power grid;In view of the deficiency that traditional PLL structure was unable to carry out adaptive tracking when faced with power grid frequency fluctuation,a zero-crossing detection method was adopted to obtain the real-time frequency of the power grid and feed it directly to the resonant frequency of the improved SOGI structure,which effectively improved the frequency adaptive ability of the PLL.Simulation and experimental results showed that the phase lock loop based on improved SOGI has the advantages of high phase lock accuracy and good dynamic performance,which could be used as a reference for the realization of single-phase photovoltaic grid-connection technology.