Grid-following voltage source converter(GFLVSC)and grid-forming voltage source converter(GFM-VSC)have different dynamic characteristics for active power-frequency and reactive power-voltage supports of the power grid....Grid-following voltage source converter(GFLVSC)and grid-forming voltage source converter(GFM-VSC)have different dynamic characteristics for active power-frequency and reactive power-voltage supports of the power grid.This paper aims to clarify and recognize the difference between gridfollowing(GFL)and grid-forming(GFM)frequency-voltage support more intuitively and clearly.Firstly,the phasor model considering circuit constraints is established based on the port circuit equations of the converter.It is revealed that the voltage and active power linearly correspond to the horizontal and vertical axes in the phasor space referenced to the grid voltage phasor.Secondly,based on topological homology,GFL and GFM controls are transformed and mapped into different trajectories.The topological similarity of the characteristic curves for GFL and GFM controls is the essential cause of their uniformity.Based on the above model,it is indicated that GFL-VSC and GFM-VSC possess uniformity with regard to active power response,type of coupling,and phasor trajectory.They differ in synchronization,power coupling mechanisms,dynamics,and active power-voltage operation domain in the quasi-steady state.Case studies are undertaken on GFL-VSC and GFM-VSC integrated into a four-machine two-area system.Simulation results verify that the dynamic uniformity and difference of GFL-VSC and GFM-VSC are intuitively and comprehensively revealed.展开更多
为解决交流系统大扰动下电流源型直流输电(line commutate converter based HVDC,LCC-HVDC)系统电磁暂态精度响应实时求取困难的问题,该文基于动态相量法仿真框架,详细讨论了大扰动下LCC-HVDC直流输电系统的建模方案,并针对工程现场的...为解决交流系统大扰动下电流源型直流输电(line commutate converter based HVDC,LCC-HVDC)系统电磁暂态精度响应实时求取困难的问题,该文基于动态相量法仿真框架,详细讨论了大扰动下LCC-HVDC直流输电系统的建模方案,并针对工程现场的计算精度与计算复杂度要求和逆变侧容易发生的换相失败现象,重构了易于拓展的仿真模型计算框架。多故障场景的仿真对比实验表明,与传统的动态相量仿真方案相比,所提出的框架能够准确反映直流系统在逆变侧交流系统受扰下的暂态响应特征,同时提高了计算速度,实现了LCC-HVDC系统暂态响应的高精度、实时化计算。展开更多
三相双有源桥(dual active bridge,DAB)直流变换器作为两个不同电压等级的直流电气系统的连接桥梁,能够实现能量的双向流动。对于闭环控制系统,DAB直流变换器控制器参数的选取影响着系统运行的稳定性。针对此问题,本文基于动态相量法对...三相双有源桥(dual active bridge,DAB)直流变换器作为两个不同电压等级的直流电气系统的连接桥梁,能够实现能量的双向流动。对于闭环控制系统,DAB直流变换器控制器参数的选取影响着系统运行的稳定性。针对此问题,本文基于动态相量法对使用单移相控制策略的三相DAB直流变换器进行建模,并考虑了闭环控制器,得到状态空间模型。基于此推导系统小信号模型,根据小信号模型进行稳定性分析,最后进行仿真验证。研究表明,本文所提模型能够分析使用单移相控制策略的三相DAB直流变换器闭环系统的小信号稳定性。展开更多
基金supported by National Key R&D Program of China(No.2022YFB4202304)。
文摘Grid-following voltage source converter(GFLVSC)and grid-forming voltage source converter(GFM-VSC)have different dynamic characteristics for active power-frequency and reactive power-voltage supports of the power grid.This paper aims to clarify and recognize the difference between gridfollowing(GFL)and grid-forming(GFM)frequency-voltage support more intuitively and clearly.Firstly,the phasor model considering circuit constraints is established based on the port circuit equations of the converter.It is revealed that the voltage and active power linearly correspond to the horizontal and vertical axes in the phasor space referenced to the grid voltage phasor.Secondly,based on topological homology,GFL and GFM controls are transformed and mapped into different trajectories.The topological similarity of the characteristic curves for GFL and GFM controls is the essential cause of their uniformity.Based on the above model,it is indicated that GFL-VSC and GFM-VSC possess uniformity with regard to active power response,type of coupling,and phasor trajectory.They differ in synchronization,power coupling mechanisms,dynamics,and active power-voltage operation domain in the quasi-steady state.Case studies are undertaken on GFL-VSC and GFM-VSC integrated into a four-machine two-area system.Simulation results verify that the dynamic uniformity and difference of GFL-VSC and GFM-VSC are intuitively and comprehensively revealed.
文摘为解决交流系统大扰动下电流源型直流输电(line commutate converter based HVDC,LCC-HVDC)系统电磁暂态精度响应实时求取困难的问题,该文基于动态相量法仿真框架,详细讨论了大扰动下LCC-HVDC直流输电系统的建模方案,并针对工程现场的计算精度与计算复杂度要求和逆变侧容易发生的换相失败现象,重构了易于拓展的仿真模型计算框架。多故障场景的仿真对比实验表明,与传统的动态相量仿真方案相比,所提出的框架能够准确反映直流系统在逆变侧交流系统受扰下的暂态响应特征,同时提高了计算速度,实现了LCC-HVDC系统暂态响应的高精度、实时化计算。
文摘三相双有源桥(dual active bridge,DAB)直流变换器作为两个不同电压等级的直流电气系统的连接桥梁,能够实现能量的双向流动。对于闭环控制系统,DAB直流变换器控制器参数的选取影响着系统运行的稳定性。针对此问题,本文基于动态相量法对使用单移相控制策略的三相DAB直流变换器进行建模,并考虑了闭环控制器,得到状态空间模型。基于此推导系统小信号模型,根据小信号模型进行稳定性分析,最后进行仿真验证。研究表明,本文所提模型能够分析使用单移相控制策略的三相DAB直流变换器闭环系统的小信号稳定性。
