高精度低计算量的离散锁频环  

High-precision Discrete-time Frequency-locked Loop with Low Computational Cost

作　　者：肖宇 黄瑞 刘谋海 刘小平 XIAO Yu;HUANG Rui;LIU Mouhai;LIU Xiaoping(State Grid Hunan Electric Power Co.,Ltd,Changsha 410004,China;Hunan Province Key Laboratory of Intelligent Electrical Measurement and Application Technology,Changsha 410004,China)

机构地区：[1]国网湖南省电力有限公司,长沙410004 [2]智能电气量测与应用技术湖南省重点实验室,长沙410004

出　　处：《电源学报》2024年第6期153-162,共10页Journal of Power Supply

基　　金：国家电网公司科技资助项目(5216AG20000D)。

摘　　要：为满足可再生能源发电系统对并网电压检测环节的低采样率、低计算量和高精度要求,提出1种避免调用三角函数的高精度离散锁频环。首先根据静止坐标系下的电压复数表达推出离散降阶广义积分器的开环传函;接着利用该开环传函的未知参数和频率关系推出低近似误差的离散降阶广义积分器;最后构造估计该未知参数的锁频环,建立该离散锁频环的二阶小信号模型,给出参数整定方法。实验结果表明:相比于最常用的三阶数字积分器离散化方法,所提离散锁频环在低采样率下具有更高的检测精度;对比统计表显示,所提离散锁频环计算量具有更少的计算成本和存储需求。To satisfy the low sampling frequency,low computational cost and high accuracy requirements of renewable energy generation systems in the grid voltage detection link,a high-precision discrete-time frequency-locked loop(FLL)which does not need to call trigonometric functions is proposed.First,the open-loop transfer function of discrete-time reduced-order generalized integrator(d-ROGI)is derived according to the expression of voltage based on complex numbers under the static coordinate system.Then,a d-ROGI with a low approximation error is derived according to the relationship between the unknown parameter of the open-loop transfer function and frequency.On this basis,the FLL for estimating the unknown parameter is constructed,the second-order small-signal model of the FLL is established,and the corresponding parameter tuning method is given.Finally,experimental results show that the FLL has a higher detection accuracy at a low sampling frequency than the most commonly used third-order numerical integrator discretization method.At the same time,it has a lower computational cost and requires less storage according to the comparison of computation cost.

关 键 词：锁频环 计算量 离散化精度 

分 类 号：TM761[电气工程—电力系统及自动化]