According to the characteristics of single-phase circuits and demand of using active filter for real-time detecting harmonic and reactive currents, a detecting method based on Fryze＇s power definition is proposed. Th...According to the characteristics of single-phase circuits and demand of using active filter for real-time detecting harmonic and reactive currents, a detecting method based on Fryze＇s power definition is proposed. The results of theoretical analysis and simula- tion show that the proposed method is effective in realtime detecting of instantaneous harmonic and reactive currents in single-phase circuits. When only detecting the total reactive currents, this method does not need a phase-locked loop circuit, and it also can be used in some special applications to provide different compensations on the ground of different requirements of electric network. Compared with the other methods based on the theory of instantaneous reactive power, this method is simple and easy to realize.展开更多
由于无法辨析并网点(point of common coupling,PCC)电压跌落的本质原因,光伏电站低压穿越(low voltage ride through,LVRT)控制与现有的孤岛保护在同时满足动作条件时缺乏选择性,影响系统的安全稳定。为研究与光伏LVRT相互协调的孤岛...由于无法辨析并网点(point of common coupling,PCC)电压跌落的本质原因,光伏电站低压穿越(low voltage ride through,LVRT)控制与现有的孤岛保护在同时满足动作条件时缺乏选择性,影响系统的安全稳定。为研究与光伏LVRT相互协调的孤岛检测方法,根据孤岛现象和电压暂态扰动现象发生时PCC谐波电压的差异,提出一种基于光伏并网点谐波电压突变的无功功率扰动孤岛检测方法。该方法在检测到PCC处的谐波电压突变后,经40 ms延时,对光伏逆变器输出的无功电流采用基于PCC频率变化量函数进行扰动,使PCC频率超出正常范围,实现孤岛检测功能。仿真结果表明:方法在保证与LVRT协调配合的前提下能在较短时间内完成对光伏电站孤岛状态的检测;此外在故障特征量较小的工况下方法依然可靠适用,消除了传统孤岛检测方法盲区的同时保证了孤岛检测的准确性。展开更多
有源电力滤波器(Active Power Filter, APF)是一种具备动态谐波抑制和无功补偿功能的新型电力电子装置,其性能优劣与所采用的拓扑结构、谐波电流检测技术和电流追踪控制方法等密切相关。为了推广在高压大容量下APF的控制技术,拓宽其应...有源电力滤波器(Active Power Filter, APF)是一种具备动态谐波抑制和无功补偿功能的新型电力电子装置,其性能优劣与所采用的拓扑结构、谐波电流检测技术和电流追踪控制方法等密切相关。为了推广在高压大容量下APF的控制技术,拓宽其应用范围,综述了国内外APF研究现状,分类整理了APF拓扑结构。归纳总结了APF的谐波检测方法和电流跟踪控制技术,综合对比了各种方法的优缺点,并从多个角度阐述了当前所存在的问题。最后展望了APF相关技术的研究方向。展开更多
文摘According to the characteristics of single-phase circuits and demand of using active filter for real-time detecting harmonic and reactive currents, a detecting method based on Fryze＇s power definition is proposed. The results of theoretical analysis and simula- tion show that the proposed method is effective in realtime detecting of instantaneous harmonic and reactive currents in single-phase circuits. When only detecting the total reactive currents, this method does not need a phase-locked loop circuit, and it also can be used in some special applications to provide different compensations on the ground of different requirements of electric network. Compared with the other methods based on the theory of instantaneous reactive power, this method is simple and easy to realize.
文摘由于无法辨析并网点(point of common coupling,PCC)电压跌落的本质原因,光伏电站低压穿越(low voltage ride through,LVRT)控制与现有的孤岛保护在同时满足动作条件时缺乏选择性,影响系统的安全稳定。为研究与光伏LVRT相互协调的孤岛检测方法,根据孤岛现象和电压暂态扰动现象发生时PCC谐波电压的差异,提出一种基于光伏并网点谐波电压突变的无功功率扰动孤岛检测方法。该方法在检测到PCC处的谐波电压突变后,经40 ms延时,对光伏逆变器输出的无功电流采用基于PCC频率变化量函数进行扰动,使PCC频率超出正常范围,实现孤岛检测功能。仿真结果表明:方法在保证与LVRT协调配合的前提下能在较短时间内完成对光伏电站孤岛状态的检测;此外在故障特征量较小的工况下方法依然可靠适用,消除了传统孤岛检测方法盲区的同时保证了孤岛检测的准确性。
文摘有源电力滤波器(Active Power Filter, APF)是一种具备动态谐波抑制和无功补偿功能的新型电力电子装置,其性能优劣与所采用的拓扑结构、谐波电流检测技术和电流追踪控制方法等密切相关。为了推广在高压大容量下APF的控制技术,拓宽其应用范围,综述了国内外APF研究现状,分类整理了APF拓扑结构。归纳总结了APF的谐波检测方法和电流跟踪控制技术,综合对比了各种方法的优缺点,并从多个角度阐述了当前所存在的问题。最后展望了APF相关技术的研究方向。
