针对直流偏移和谐波干扰的单相锁相环

Single-Phase Phase-Locked Loop for DC Offset and Harmonic Interference

针对电网普遍存在的直流偏移和谐波干扰等问题,提出一种基于二阶广义积分器锁相环(SOGI-PLL)的改进型锁相环算法。该方法在前级二阶广义积分器(SOGI)中增加积分支路并且改为固定频率结构,以抑制直流偏移和简化参数设计;在后级锁相环(PLL)环路中引入滑动平均值滤波器(MAF),去掉比例积分控制器的积分环节,以增强滤波性能和加快动态响应速度。利用伯德图分析和小信号模型推导等方法,指导改进结构设计,确定相应的参数。所提出的改进型单相锁相环技术可以有效地消除直流偏移和高频谐波,同时具备良好的动态性能和稳定性。最后,通过Matlab/Simulink仿真和相关实验验证了该方法的优越性。

Aiming at the common problems of DC offset and harmonic interference in power grids,an improved phase-locked loop algorithm based on second-order generalized integrator phase-locked loop(SOGI-PLL)is proposed.In order to suppress the DC offset and simplify the parameter design,an integral branch is added to the pre-stage second-order generalized integrator(SOGI),and the SOGI is changed to a fixed frequency structure.A moving average filter is introduced into the post-stage loop of phase-locked loop(PLL)to enhance filtering performance.For the purpose of speeding up dynamic response,the integral part of PI controller is removed.Bode diagram analysis and small signal model derivation are used to improve structure design and determine the corresponding parameters.The proposed improved single-phase phase-locked loop technology can effectively eliminate DC offset and high-frequency harmonics,while having good dynamic performance and stability.Finally,Matlab/Simulink simulation and related experiments verify the proposed method.