瞬时电流

On the basis of the above results of detecting methods, the instruction signal calculating circuit is designed according to i〓, i〓 calculating mode. Compensation current generating circuit is also designed and implemented. Its current following circuit is designed according to the instantaneous value comparing mode that used constant time control. The source current detection based control mode and composite control mode and their implementation are firstly introduced in our country. The method and the principle of dc side capacitor voltage control are explained clearly.

根据检测方法的研究成果，采用i〓、i〓运算方式构成并联型电力有源滤波器的指令电流运算电路；对补偿电流发生电路进行了电路设计和实施，其中电流跟踪控制电路采用电流跟随性能好、可靠性高的定时控制瞬时值比较方式；在国内首次研究并实施检测电源电流控制方式和复合控制方式；清楚地阐明了并联型电力有源滤波器直流侧电压控制的原理和方法，并在装置中实施。

According to the instantaneous value of transmission line voltage, the current instantaneous values of shunt reactors and 17 equivalent circuit capacitance can be calculated.

由线路电压瞬时值分别实时计算出流入并联电抗器和流入线路Ⅱ型等值电路两侧电容的电流瞬时值，再从线路每侧电流除去这两部分电流，用得到的新电流瞬时值作常规采样值差动和故障分量采样值差动保护计算。

From the perspective of minimum transmission losses, an instantaneous reactive power theory for systems with any number of phases and with or without neutral line is developed. Under the new definition, each quantity has its own physical meaning, and the zero sequence current can be decomposed into active and reactive components. Furthermore, a generalized compensation method for zero sequence current is developed.

从输电损耗最小的角度出发，提出了任意相无中性线或有中性线系统的瞬时无功功率理论，在新的理论下，每个量都有清晰的物理意义，且能分解出零序电流的有功分量和无功分量，并给出了通用的零序电流补偿方法，揭示了瞬时无功功率理论与传统平均意义下的无功功率理论的联系及本质区别，从而为研究HVDC-VSC及各种FACTS装置的无功功率控制奠定了理论基础。

On the basis, this paper provide two harmonic current detect methods, and do deep research on the using zero current divided method to achieve harmonic current and instantaneous reactive current real time detecting method.

在此基础上，提出了两种基于该理论的谐波电流检测方法，并对采用零线电流分离法实现的谐波电流及瞬时无功电流的实时检测方法进行了深入研究。

A detailed analysis of the main circuit introduction, control method and working principle of the direct-drive wind energy conversion system are given to introduce the two important parts a of this paper: First part is the control method of the multiple boost convertor, the important instantaneous current control method of this paper is given through the analysis of the main circuit structure, control method and working principle. Then a steady-state analysis for low-frequency, a high-frequency component analysis, and a closed-loop tracking performance analysis for dynamic response are provided to analyze the method proposed; And the second part is the control method of invertor.

在系统变流器整体结构分析的基础上，引出本文重点研究的两个变流环节的控制：第一部分是系统升压斩波器的控制，通过分析相关主电路结构、原理，建立了数学模型，引出本文重点研究的瞬时值控制策略的概念和具体实现，并对升压斩波器的瞬时值控制策略进行了详细的高频、低频模型分析和稳态、动态性能分析；第二部分是系统并网逆变器的控制，通过对逆变器主电路的数学建模和控制要求分析，研究了并网逆变器的瞬时值控制策略，包括电感电流控制内环和直流电压控制外环的具体设计和实现方法。

After the tripped phase current from shunt reactor was calculated using the transient fault model as the prototype whether transient or permanent fault, the difference between the calculated current and the measured one of the fault phase from shunt reactor was employed to identify permanent fault. When the single-phase fault is transient, the calculated current is close to the actual measured current.

该方法以瞬时性故障为参考模型，求取并联电抗器故障相电流，采用该求取电流与并联电抗器故障相实际测量电流之差同中性点小电抗器电流幅值比来实现永久性故障的判别。

With Matlab simulation software, a research on simulation of harmonic detection means based on instantaneous reactive power theory is carried out, and a detailed analyse of the simulation result is presented. The result indicates: the harmonic detection means based on instantaneous reactive power theory can detect harmonic and reactive component in three-phase current precisely and re...

利用Matlab仿真软件，对基于瞬时无功功率理论谐波检测方法进行了仿真研究，并对仿真结果进行了较为详细地分析，仿真结果表明：基于瞬时无功功率理论谐波检测方法可以准确、实时地检测出三相电流中的谐波电流及无功电流，可为抑制谐波和无功补偿提供可靠的谐波及无功电流分量。

In order to let the active power filter could be used in 3-phase 4 wires circuits, a new method of harmonics detection is given in this paper, which is based on p-q method and ip-iq method of the instantaneous reactive power theory. This method remove the zero current.

综合运用瞬时无功理论中的p-q法和法，提出了一种新的基于瞬时无功理论的有效的三相四线制谐波检测新方法，此方法能将三相电流中的零序电流剔除。

By fitting the function reflects the changing trends in the data, access overloading current round of fighting, and in accordance with a real-time measurement of the current round of fighting, from coal forecast instantaneous flow, and flow measuring devices and video detection to the instantaneous flow of coal from joint participation control, at the same time on different Bucket Meidui set rated from coal flow from coal bucket wheel and different operating current limit, to ensure that coal Bucket from the high efficiency and safe operation.

通过拟合的函数关系反映出的数据变化趋势，获取斗轮超载电流，并根据实时测得的斗轮电流，预测瞬时取煤流量，并与视频流量检测装置检测到的瞬时取煤流量共同参与控制，同时为斗轮机对不同煤堆取煤设定额定取煤流量和不同的斗轮工作电流上限，确保斗轮机取煤的高效率和运行安全。

At first the current sampling values pass through virtual digital CVTs. And then the voltage and current sampling values are processed by a low pass filter. According to the instantaneous value of transmission line voltage, the current instantaneous values of shunt reactors and P equivalent circuit capacitance can be calculated. After removing these two kinds of current, sampling value differential protection based on all components and fault component can be applied.

由线路电压瞬时值分别实时计算出流入并联电抗器和流入线路Π型等值电路两侧电容的电流瞬时值，再从线路每侧电流除去这两部分电流，用得到的新电流瞬时值作常规采样值差动和故障分量采样值差动保护计算。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。