柔性直流输电系统接入非理想电网的改进DSOGI同步方案
Improved DSOGI Synchronization Scheme for Flexible DC Transmission System Connected to Non-ideal Power Grid
薛云涛 1任百群 2谢剑翔 1陈宇昇 1鄞庆佳1
作者信息
- 1. 广东电网有限责任公司广州供电局,广州 510630
- 2. 南京南瑞继保电气有限公司,南京 211102
- 折叠
摘要
针对非理想电网下 VSC-HVDC 系统中同步旋转坐标系锁相环 SRF-PLL(synchroncus reference frame phase-locked loop)、双二阶广义积分器锁相环DSOGI-PLL(dual second-order generalized integrator phase-locked loop)等传统锁相环无法准确追踪电网基波正序电压相位,致使不同程度的锁相误差影响VSC控制性能,降低系统稳定性等问题,提出了改进型DSOGI-PLL方案.首先,根据SOGI-QSG的Bode图分析其对不同频率的衰减特性,得出DSOGI-PLL的适用局限性;然后,基于谐波电网电压,在DSOGI基础上引入重复控制内模,实现对谐波信号的实时跟踪调节,以抑制谐波电压干扰.同时考虑到直流偏置与电网电压频率波动,提出直流偏置消除与频率自适应方法,实现对电网相位的自适应跟踪;最后,通过仿真及实验结果对比,验证了所提策略的优越性.
Abstract
The traditional phase-locked loops(PLLs)in a VSC-HVDC system such as a synchronous reference frame PLL(SRF-PLL)and a dual second-order generalized integrator PLL(DSOGI-PLL)cannot accurately track the positive-sequence voltage phase of grid fundamental wave under non-ideal power grid,which will cause different degrees of phase-locked error,affect the control performance of VSC and reduce the system stability.To solve this problem,an improved DSOGI-PLL scheme is proposed.First,the attenuation characteristics of SOGI-QSG at different frequencies are analyzed according to the Bode diagram,and the limitations of DSOGI-PLL applications are obtained.Then,based on the voltage of harmonic grid,the internal model of repetitive control is introduced on the basis of DSOGI to realize the real-time tracking and regulation of harmonic signals,thus suppressing the harmonic voltage interference.At the same time,considering the DC bias and voltage frequency fluctuation of power grid,a method of DC bias elimination and frequency adaptation is proposed to realize the adaptive phase tracking of power grid.Finally,the superiority of the proposed strategy was verified through a comparison between the simulation and experimental results.
关键词
柔性直流输电/锁相环/不平衡/谐波/直流偏置/频率自适应Key words
Flexible DC transmission/phase-locked loop(PLL)/imbalance/harmonic/DC bias/frequency adaptation引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据