摘要
针对现有并网逆变器在电网电压谐波复杂的情况下难以精确锁定电压频率和相位的问题,结合传统锁相环结构与自适应算法的理论提出一种高精度的锁相方法。依据对传统锁相环在复杂电网下的弊端分析,确定了锁相环采用传统低通滤波器、带通滤波器时的滤波效果与延时的矛盾关系。根据最小均方算法的高自适应特性与快速跟踪特点,结合锁相环中坐标变换公式,确定算法的输入输出以及权重矩阵,构建基于派克变换的最小均方算法矩阵模型。通过将所需的电压正序分量设置为不断更新的权重矩阵来进行高精度的滤波,同时通过引入均方瞬时误差和自相关估计均值来进行变步长控制,提高滤波更新速度,以适用于复杂程度不确定的电网电压进行自适应滤波锁相。对仿真和样机实验的结果表明:采用基于派克变换的最小均方算法的改进型双二阶广义积分锁相方法,可以在不降低动态响应速度的前提下,提高锁相环的滤波效果,进而提高并网逆变器在电网畸变严重场景下锁定电压频率和相位的跟踪精度。
A high-precision phase-locked method was proposed by combining traditional phase-locked loops and adaptive algorithms to address the difficulty of accurately locking the voltage frequency and phase of existing grid connected inverters under complex grid voltage conditions.Based on the analysis of the drawbacks of traditional phase-locked loops,the contradiction between the filtering effect and delay when using traditional filters in phase-locked loops was determined.Based on the adaptive filtering characteristics of the minimum mean square algorithm and the coordinate transformation formula in the phase-locked loop,the input,output,and weight matrix of the algorithm were determined,and a minimum mean square algorithm matrix model based on the Parker transform was constructed.High precision filtering was achieved by setting the required voltage positive sequence component as a continuously updated weight matrix,while variable step size control was implemented by introducing mean square instantaneous error and autocorrelation estimation mean.The experimental results show that using an improved phase-locked method based on the minimum mean square algorithm can improve the filtering effect of the phase-locked loop without reducing the dynamic response speed,thereby improving the phase-locked accuracy of the grid connected inverter under grid distortion.
作者
黄海宏
刘远朋
王海欣
HUANG Haihong;LIU Yuanpeng;WANG Haixin(School of Electrical Engineering and Automation,Hefei University of Technology,Hefei 230009)
出处
《电机与控制学报》
EI
CSCD
北大核心
2024年第3期43-55,共13页
Electric Machines and Control
基金
国家自然科学基金(51177037)。
关键词
锁相环
自适应滤波
双二阶广义积分
最小均方算法
变步长
phase locked loops
adaptive filtering
double second-order generalized integrator
least mean square
variable step
