谐波

Based on the theory of instantaneous reactive power, the multiple frequency rotate transform theory is put forward. It overcomes the defect of that the theory of instantaneous reactive power can only measure the harmonic total amount. The positive sequence and negative sequence k-multiple frequency rotate coordinate is respectively put forward in detail.

倍频旋转变换理论是基于瞬时无功功率理论提出的，它克服了瞬时无功功率理论测量方法只能测量谐波总量的缺陷，该理论分别针对正序谐波和负序谐波，提出正向和负向倍频旋转坐标，通过k—倍频旋转坐标可将k次谐波分离出来。

In order to ensure that self-compensating devices for reactive power work stably and reliably in low-voltage electric power system, this paper introduces a new method and steps of selecting compensating devices by comparing their types, based on the theory of reactive power in non-sinusoidal alternating circuit.

产生谐波的根本原因是电力系统中器件、设备的非线性，即使供给这些器件、设备的电源是理想的正弦波形电压，电网供给它们的电流也是非正弦波形，即产生了谐波电流，当谐波电流流过线路后，产生谐波压降，使电网电压失真。

The result indicates that the harmonic detection means based on instantaneous reactive power theory can detect harmonic and reactive component in three-phase current precisely and real-time, to supply reliable harmonic and reactive current for harmonic restraint and reactive power compensation.

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。

And by means of semiclassical theory, the changes of HHG for realistic hydrogen atom in the static electric field is explained.

已有的理论和实验研究表明，原子在强激光场中产生的高次谐波的典型特征是：随谐波阶数的增加，开始几阶谐波强度很快地下降，接着出现了一个"平台"，在平台区域内，谐波的

Because a bulk smoothing capacitor is usually installed on the DC side of many AC to DC converters, the characteristics of harmonic loads will be influenced by this capacitor. Nowadays, shunt active power filters can't reduce harmonics effectively for this voltage type harmonic-producing load. Therefore, a series active power filter is designed to meet the requirements of voltage-sourced harmonic loads. Both source current and load voltage are detected in order to reach the compensation voltage for the SAPF.

由於许多交直流电源转换器均在直流端并联一直流电容以作为稳压之用，此大电容将造成负载谐波特性的改变；此类谐波源负载，如果使用现今常见的并联型主动式电力滤波器并不能很有效解决此类谐波问题；因此本文将采用串联型主动式电力滤波器，并配合同时量测电源电流及负载电压的混合式控制模式，即可有效解决此类谐波问题。

The voltage of active power filter can be controlled by system harmonic current, load harmonic current ,harmonic current of spur track, load harmonic voltage, or combination of them. Further more, a comparison research on different control strategies is put forward, the control strategy of ideal filtering is got ,and the system control strategy is determined at last.

HAPF的谐波电压可以受控于系统谐波电流、负载谐波电流、滤波支路谐波电流、负载谐波电压或它们的组合，本文对不同的控制策略进行比较，最后得出理想滤波控制策略，最终确定HAPF的系统控制策略。

Aiming at a class of complex electromechanical systems, such as 4-high or multi-high cold mills and continual mills, we firstly construct mathematical models of every subsystems by means of structural principle modeling method; nextly, get the overall mathematical model of electromechanical drive system by joining together these subsystems'models according to coupling variables and parameters; we finally simplify the overall model according to time-scale principle which can retain main eigenvalues and significant state variables, and obtain a practical mathematical model of complex electromechanical system. By simulating the CM04 temper mill's model constructed by above-mentioned method, we test and verify that the modeling method is effective and practical. The study analyzes and researches the electromechanical coupling facts and acting laws existing in complex electromechanical system.

提出了系统的总体测试方案，设计了高保真度的信号隔离和缓冲器，解决了从大功率、大电流复杂机电系统主回路中提取真实谐波分量、而又能不影响系统正常运行的难题；发现了谐波电流对平整机工作状态的影响规律；确认谐波电流是可能引起平整机工况奇异、产生机电耦合振动、导致带材产品表面出现明暗振纹的一个因素；提出了一种多相整流电路谐波电流的分析计算方法，用该方法对平整机三相桥式整流供电电路的谐波分量进行了理论分析和计算，计算结果与实测结果能得到相互验证，说明该方法是可行的，实测结果是可靠的。

By study, majority of the research productions and theoretical papers are about how to control harmonic, and the harmonic analysis methods that were introduced are generally applied in large power system, these harmonic analysis methods usually use harmonic network's mathematic model (the conductance and susceptance matrix of the node). But because of the dissymmetry of some elements in power system, the mathematic model is very complex, so it is very complicated to calculate by these methods, we commonly combine with computer and use them to analyze large power system.

通过学习和了解，现有的研究成果和理论文章多数是介绍谐波的治理方法，而介绍谐波分析方法的论文一般是针对大型电力系统进行分析和研究的，这些谐波分析方法通常利用谐波网络的数学模型（谐波网络的节点导纳矩阵）进行分析，由于电力系统中的某些元件的不对称性，使得数学模型复杂，计算起来极为繁琐，因此，一般结合计算机用于分析大型电力系统。

Then the error sources of the reaction type and electron type electric energy mete were analyzed and the theory analysis result through the concrete test have been proved. At last, the main conclusion has been drawn. When the induction type electric energy meter measures harmonics energy, the negative error characteristic appears. The higher the frequency of harmonics is, the greater the error is. The electron type electric energy meter can measure harmonics energy accurately in general cases. Except thermo-electrical conversion type electron type power meter, reaction type and electron type electric energy meter can measure direct current power.

本论文通过分析感应式和电子式电能表的工作原理推导出了电能表计量电能的数学模型；分析了感应式和电子式电能表的误差来源以及谐波对计量的影响，并通过具体的试验对理论分析结果进行了验证；得出了如下谐波对电能表计量影响的主要结论：感应式电能表计量谐波电能时，呈现负的误差特性，谐波频率越高，误差越大；电子式电能表在其频响范围内可以准确计量谐波电能。

The principle of the novel single-phase hybrid active power filter is described in detail. Based on the above analysis, Kalman filtering approach for estimation of harmonics is presented to improve the speed and precision of harmonic detection, and it also can avoid the influence made by voltage distortion on harmonic detection. A new current control strategy based on energy balance is presented to regulate the active part absorbing or releasing active power and control the inverter to produce current opposite to the harmonic current reflowing in injection branch, the above method combined with harmonic current tracking control that keeps the stabilization of dc-side voltage and improve the reliability of the system.

并详细分析了系统的滤波原理，提出了基于卡尔曼增益自调整的改进型动态谐波含量估计方法，能够快速准确的跟踪检测电网谐波电流，并且克服了电力机车等冲击性负荷引起的电网电压畸变对谐波检测精度的影响；提出了基于逆变器两侧能量平衡的电流控制方法使有源部分吸收或释放一定有功或无功功率及产生与注入支路回灌谐波电流相反的抑制电流，然后联合电网谐波电流跟踪控制以获得系统参考信号，保证了直流侧电压的稳定，提高了装置可靠性，增强了系统滤波性能。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。