查询词典 harmonic analysis

The pollution problem caused by harmonic sources to power system has become more and more serious. As traditional filter devices , passive filters can not only suppress the harmonic but also compensate the reactive power and are still a widely used measure for harmonic suppression.

摘 要 谐波源对电网的污染问题已经日益引起人们的关注，而无源滤波器作为传统的滤波装置，既可以滤除谐波，同时可以兼顾无功补偿的需要，目前仍是应用较为广泛的抑制谐波污染的措施。

The power variation of the targeted harmonic signal and harmonic suppression ratio were calculated and evaluated. The theoretical caculations and simulated results suggest that power variation can be maintained within 1 dB with dc bias drift less than 5% and the harmonic suppression ratio is stable in the SSB RoF link.

理论计算和仿真结果表明，偏置漂移会使目标信号的功率抖动增大，但当偏置漂移量小于5％时，功率抖动小于1 dB，而谐波抑制比保持稳定；分析了与非理想光电调制器啁啾相关的有限消光比和双臂驱动不平衡度对RoF链路性能的影响，有限消光比会增加目标信号的功率抖动并降低谐波抑制比，而通过优化调制器的双臂驱动不平衡度可以提高单边带调制RoF链路性能。

We choose the TMS320VC5402, digital signal processor, as the computing unit, filtering the sampled signal, truncating the harmonic whose frequence greater than 2500hz, then we use the window-interpolation FFT algorithm to get the refined frequence, amplitude, phase of harmonic in sampled voltage and current, other parameter such as harmonic ratio, active power, reactive power, power factor, three-phase unbalance can be also computed base one the result of window-interpolation FFT.

选用TMS320VC5402高速数字信号处理器作为运算单元，先对采样信号进行数字滤波，去除50次以上谐波分量，然后应用加窗双峰插值FFT算法计算电压电流的各次谐波频率、幅值和相位，以及谐波含有率、有功功率、无功功率、三相不平衡度等各项电能指标，同时利用锁相环电路硬件跟踪电网频率以减小采样失步度。

The manipulation of harmonic frequencies and the synthesis of harmonic frequencies are based on the harmonic rank.

泛音频率的处理和泛音频率的合成基于泛音次数。

Secondly, contraposes the limitation of the traditional harmonic current detecting method based on neural network, presents the method that combines the neural network and auto adaptive harmonic current detecting method based on the principle of noise each other eliminating.As the characteristics that are small calculative quantity, fast converge, without local minimal point of Redial Basis Function, this dissertation forms a new harmonic current detecting method based on RBF.

其次，针对传统的谐波电流检测方法的缺陷，提出将神经网络与基于噪声抵消原理的自适应谐波检测相结合，利用径向基函数运算量小、收敛快、无局部极小值等优点，构造了一种基于径向基函数神经网络的谐波电流检测方法，仿真结果表明该检测方法具有很好的动态响应及畸变电流检测精度。

In chapter 4, the Newlands harmonic wavelet is improved and a new type of wavelet with better time-frequency characteristic is constructed. Frequency band of signal can be divided arbitrary with the improved harmonic wavelet so that the phenomena of aliasing are reduced. Several typical fault signals in Electromechanical System are analyzed with it. In addition to the improved harmonic wavelet in chapter 4, a new half-complex wavelet is presented to improve the complex wavelet, which is given by Chaari.O. A unilateral recursive algorithm is derived to improve the real-time characteristic. A parameter n is imported to make the time-frequency and filtering characteristics of it better and its ability of extracting fault feature is enhanced.

第四章通过对Newland谐波小波的改进构造频域紧支撑、时域性能良好的新型小波函数，可实现信号频带的任意划分，从而减少频带混叠现象，采用改进的谐波小波对多种典型的机电系统故障信号进行了分析；以Chaari.O复小波为基础构造了一个半复小波，从提高复小波算法的实时性出发，推导了半复小波单向递推算法，通过给原小波设置可调参数的方法，实现了一种能满足小波基本条件的复值小波，可以通过参数的调整调节小波滤波器在Hilbert空间的时频特性和相应的滤波性能，以加强半复小波对故障特征的提取能力。

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。

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。

Based on the single-particle theory, we inspect the effects of harmonic wiggler field components on the outputs of free electron lasers (including the components of fundamental and harmonic frequecies), and derive the complete simulation equations for millimeter wave FELs. Meanwhile under the condition that the harmonic wiggler fields are much smaller than the fundamental one, we describe the effects simulated. Using the improved 3D WAGFEL code.

在单粒子理论的基础上，详细考察了摇摆场谐波分量对自由电子激光输出功率的影响，给出了完整的模拟方程组，并在摇摆场谐波振幅远小于其基波振幅值的假定下，利用三维WAGFEL程序和毫米波自由电子激光放大器的参数模拟计算了摇摆场谐波对自由电子激光基频输出功率的影响。

Then, aiming at harmonic current problem of single-phase circuit, I predigest the triphase instantaneous harmonic and reactive power theory to be used in detecting harmonic current of single-phase circuit.

然后，针对单相电路中的谐波电流问题，对三相的瞬时无功功率理论进行简化，使其应用于单相的谐波电流检测当中。

Hanna: That's over now, isn't it?

都结束了，对吗

You must be ill. You look so pale.

你一定是病了，你的脸色苍白。