参数变换

The interharmonics cannot be achieved accurately by using FFT for an unsynchronized sample sequence analysis because of large errors in such cases.

快速傅立叶变换在非同步采样情况下存在着较大的误差，因而无法直接获取准确的间谐波参数。

The paper analyses the power converter modul's principle of operation, key techniques and solutions emphatically. We design circuit parameters and developed a prototype.

论文重点分析了功率变换模块的工作原理、关键技术及解决方法，设计了电路参数，研制了样机进行了实验研究。

The principle and design method of active clamped synchronous rectification forward converter are introduced in this article.

本文简要介绍了有源箝位同步整流正激变换器的原理及主要参数的设计方法，给出了具体的设计公式和样饥结果。

It makes use of transform to dispose delay, generates residual through parity relations, decouples disturbance by parameter design, then diagnoses the control fault of the networked system, and provides the simulation results.

利用：变换来处理延时，由等价关系产生残差。通过参数设计解耦干扰向量，从而对网络化系统的控制故障进行了诊断。并提供了仿真结果。

Comparing with existing solutions, new method can utilize generators' speed signal measured by wide area measurement systems directly and detailed model and parameter of power system components were not needed. After sphering measurement-data, ICA with maximal negentropy criterion was carried out to obtain feature matrix. By this means high-dimension data of multi-machine perturbed trajectories were reduced to lower dimensions, and coherent generator groups were identified by pattern recognition consequently. Simulation results of 36-bus system with 8-generator and planning northwest China 750 kV power grid show that noise signals and bad data can be eliminated. This method is accurate in identifying coherent generator groups.

与现有方法相比，这种方法不需要获得系统元件模型和参数，而是直接球化广域测量系统(wide area measurement systems，WAMS)提供的发电机电角速度信号，再利用最大负熵准则进行独立分量分析得到特征矩阵，将高维数的多机受扰轨迹数据变换到低维空间，通过模式识别得到分群结果。8机36节点系统和西北750 kV电网规划系统算例表明，该方法能有效消除噪音和坏数据的影响，准确识别出同调机群。

In this paper Ⅰ successfully applied these methods to fault diagnosis, and presenting some new innovative machinery fault diagnosis method; First Ⅰ present a new gear wornout fault diagnosis method, this method use the vibration signal's time-frequency attribute and instantaneous phase undulation to accurately detect gear's fault, and by comparing with the traditional frequency domain analysis method, this method reveals that many nonlinear and nonstationary characteristic exist in gear's vibration, this tell us that if we use frequency domain analysis method without pay attention to the signal's characteristic, we could get wrong diagnostic result; Then Ⅰ present a new bearing fault diagnosis method, this method use ATVFD and Hilbert transform to do envelop demodulation,Ⅰ analyze the envelop with time-frequency method and find out that this method is more accurate then traditional method.Ⅰ also explain that the modulation of the fault to the carrier wave may also be non-stationary and nonlinear; Finally Ⅰ present a cylinder pressure measurement method of diesel engine by means of vibration, cylinder pressure is an important parameter of diesel engine fault diagnosis, the pressure measuring is simplified a lot by this method,Ⅰ also use the ATVFD and time-frequency analysis to realize it.

本文中将上述理论方法成功地应用到故障诊断中去，提出了几点创新性的诊断方法；提出了一种齿轮磨损故障诊断的新方法，该方法利用振动信号能量的时频域分布特征与瞬时相位波动特征可以进行精确的齿轮故障诊断，并通过与传统的频域诊断方法的比较，揭示出齿轮振动中存在的明显的非线性与非平稳特征，说明了不加选择地利用频域分析方法进行齿轮故障诊断很可能会得到错误的诊断结果；提出了一种轴承故障诊断的新方法，该方法利用ATVFD分解与Hilbert变换进行包络解调，并对解调得到的包络信号进行时频域分析，可以实现更加准确轴承故障诊断，说明了故障对载波信号的调制往往也是非平稳与非线性的；提出了一种利用振动信号进行柴油机汽缸内压力检测的新方法，柴油机汽缸压力的变化是柴油机故障诊断的重要参数，利用振动方法可大大简化汽缸压力的检测过程，该方法也是综合利用ATVFD分解与时频域分析方法实现的。

First, it gests the bandwidth parameter and center frequency of Gabor filter based on human vision and the size of texture image, constructing the multichannel Gabor filters and extracting the Gabor multitemporal and multidirectional energy features of image in the time and frequency domain and implementing nonlinear transform and Gauss lowpass filtering in the feature space.

首先根据人类视觉特性选定Gabor滤波器的频率带宽参数，利用图像大小确定滤波器的中心频率，构造一组多通道的Gabor滤波器在时域和频域中提取图像多方向和多分辨率的Gabor能量特征，对特征空间进行非线性变换和Gauss滤波处理，最后通过Kmeans方法实现纹理图像的分割。

Through the analysis of the work principle of three phases voltage resource PWM converter, set up the low and high mathematic models, deduce the restriction equations about grid voltage, grid current, modulation voltage and the DC output voltage and the calculation equations of the AC-side inductance and the DC-side capacitance. There are two control strategies are adopted: Predicted current control strategy and voltage-current two closed-loop control strategy, and give a comparison by theory and practice.

通过分析三相电压源型PWM变换器的工作原理，分别分析了低频和高频数学模型，并推导出了交流侧电压电流、调制电压、直流侧电压之间的数学约束关系以及交流侧电感和直流支撑电容参数的选取依据公式；分析对比了两种控制策略：预测电流控制和电压电流双闭环控制并加以实验验证；同时采用了负载电流前馈补偿和本文提出的一种基于专家系统的神经元新型智能PI控制器两种方法大大提高了整个系统的动态响应性能，并在仿真和实验中加以验证，这也是本文研究的重点内容之一。

Because the error mainly comes from theresonant region, the error correction method can only be used in resonant region, andcan effectively improve the efficiency of the statistical analyzing solutions. Two types of the mistuned bladed disks, whose friction damping are blade dryfriction damping and blade-to-blade dry friction damping, are modeled respectively. Amulti-harmonic method which can employ the fast Fourier transformationtechnique is proposed to investigate the vibratory response of the bladed disks withthese two types of nonlinear friction damping. Formulations of the solution for thesetwo types of motion functions are deduced. The characteristics of the forced responseof the bladed disks with these two dry friction damping are analyzed and summarizedunder various system parameters. The vibratory response of the bladed disk with dryfriction scatter mistuning is investigated.

针对叶盘系统中两类主要的非线性干摩擦阻尼形式，分别建立了具有叶片干摩擦阻尼和叶间干摩擦阻尼的失谐叶盘系统的非线性力学模型；提出了一种可利用快速傅立叶变换技术的多谐波分析方法；分别推导了具有这两类干摩擦阻尼形式的叶盘系统运动方程的求解公式；在各种系统参数条件下，研究了干摩擦阻尼失谐叶盘系统的受迫振动响应特性；对具有干摩擦散乱失谐的叶盘系统振动响应进行了研究，分析总结了干摩擦散乱失谐对叶盘系统振动响应特性的特殊影响规律。

The method, based on MNA equations and numerical inversion of Laplace transform, is used for the transient simulation of interconnection circuits with frequency-dependent parameter.

本文运用基于复频域MNA方程的数值反拉普拉斯变换法分析高速集成电路中频变参数互连电路的时域响应。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。