电压斩波控制的开关磁阻电机非线性仿真分析

依据通过有限元(ANSYS)计算得到的开关磁阻电机φ-i-θ数据,借助于MATLAB/Simulink环境建立了三相开关磁阻电机非线性模型,由该模型可直接输出电机各相瞬时转矩、磁链和运动电势的大小。在此基础上在电压PWM控制下对运动电势解耦,可以在克服由于电机运动电势非线性特性对电流调节器性能的影响。最后通过仿真,验证了SRM非线性模型的正确性也表明了运动电势解耦控制方法的可行性。     

基于Matlab的开关磁阻电机控制系统仿真建模研究

在分析开关磁阻电机(SRM)数学模型的基础上，提出了SRM控制系统仿真建模的新方法。在Matlab／Simulink中，建立独立的功能模块，如电机本体模块、速度控制模块、电流控制模块、转角选择模块等，再进行功能模块的有机整合，搭建SRM控制系统的仿真模型。系统采用双闭环控制：速度环采用PI控制，电流环采用角位置控制与电流斩波控制相结合的方法，保证了SRM在低速或高速运行时都可获得满意的性能。仿真结果证明了该SRM建模方法的合理性、有效性，为实际电机控制系统的设计和调试提供了新的思路。     

开关磁阻电动机控制器的仿真研究

介绍了开关磁阻电动机的准线性数学模型，以此为基础，使用Matlab／Simulink建立了通用的开关磁阻电机仿真模型；设计了电压斩波控制，电流斩波控制，换相控制等开关磁阻电机控制器的通用模块，从而建立了开关磁阻驱动系统仿真模块库。研究重点是设计基于皮特里网络(Petri-Net)的SRD控制策略选择器，并提出适用于微控制器实时控制的皮特里网络算法，仿真和实验结果都表明对优化SRD的四象限运行控制有较明显的效果，可应用于实际。     

基于转矩观测法的开关磁阻电机转矩脉动抑制

研究抑制开关磁阻电机(SRM)的振动和噪声是改善开关磁阻电动机调速系统(SRD)性能的重要课题之一。基于SRD的非线性动态仿真模型,研究了基于转矩观测法的转矩脉动抑制。针对SR电机的时变、非线性特性,对闭环系统的速度调节器采用自适应模糊PID控制器进行转速调节,仿真结果表明该系统具有良好的转矩脉动抑制效果。     

基于磁链轨迹的开关磁阻电机能量效率仿真研究

利用Matlab中的电力系统工具箱(PSB)建立了开关磁阻电机的非线性仿真模型.基于电机运行时的磁链轨迹,详细分析了开关磁阻电动机及发电机的能量转换过程并推导出了它的能量效率计算公式.以开关磁阻电动机为例对几种能够提高电机有效输出能量的优化方法进行了分析,仿真及实验研究,仿真及实验结果直观地表明了所论及优化方法的有效性.基于磁链轨迹的仿真分析方法的引入以及几种优化方法的仿真及实验结果对开关磁阻电机的优化设计及控制有一定的参考价值.     

基于DITC的开关磁阻电机转矩脉动抑制仿真研究

基于直接瞬时转矩控制(DITC)理论,介绍了开关磁阻电机的DITC方法及其数学模型,并在此基础上,采用Matlab/Simulink进行了开关磁阻电机DITC系统转矩脉动抑制的仿真研究.仿真结果表明DITC控制结构简单、不需要进行电流控制,直接从参考转矩和当前输出转矩进行比较得到每一相的开关状态,能有效地抑制开关磁阻电机的转矩脉动.系统实验也验证了开关磁阻电机转矩脉动抑制仿真研究的正确性.     

开关磁阻发电系统非线性建模及故障仿真研究

在开关磁阻电机非线性电感模型的基础之上,利用Matlab中的电力系统工具箱(PSB)建立了一个四相8/6极开关磁阻发电系统(SRG)完整的非线性模型,仿真结果验证了该模型的适用性.通过对模型施加不同的故障条件,仿真了系统在电枢绕组故障,功率变换器故障以及负载短路故障等多种故障情况下的电压,电流输出波形,并与相关文献的分析结果进行了横向比较.仿真结果表明,开关磁阻发电系统具有较高的容错能力.所提出的故障建模方法及仿真结果对开关磁阻发电系统的故障诊断及容错研究有一定的参考价值.     

多电飞机开关磁阻发电系统的数字仿真研究

分析了多电飞机开关磁阻发电系统的运行机理，针对开关磁阻发电机（SRG）的特点，应用MATLAB/Simulink中的电力系统工具箱（PSB）建立了开关磁阻发电系统的仿真模型，并详细的介绍了系统模型的内部结构和Simulink/PSB建模方法。利用该模型对发电系统的稳态和动态特性进行仿真，将仿真结果与实测或其它仿真方法的输出进行比较，结果基本一致，验证了系统模型的正确性，从而为多电飞机电源系统的特性分析提供了一种可行的研究方法。     

开关磁阻电机多种控制策略的仿真比较研究

针对开关磁阻电机非线性严重、变量耦合强烈、电磁关系难以分析的特点,采用了直接转矩控制方法。利用PI调节器分别对电机转矩和磁链进行控制,并且分别与滞环直接转矩控制和电流斩波控制进行了实验仿真的分析和对比,证明PI直接转矩控制系统准确的控制了磁链,减小了电流噪声,提高了响应速度,有效的抑制了转矩的脉动。     

基于空间矢量PWM的新型直接转矩控制系统仿真

针对传统的直接转矩控制（DTC）转矩脉动大、开关频率不恒定等向题，在分析永磁同步电机（PMSM）数学模型的基础上，提出了一种善于空间矢量脉宽调制（SVPWM）技术的新型直接转矩控制系统，并利用MATLAB仿真软件建立了系统模型。该系统采用PI控制器调节磁链和转矩．逆变器由SVPWM控制．仿真结果表明该直接转矩控制系统设计是正确的，并能有效减小磁链和转矩脉动，改善控制系统的性能。     

Novel approach for identifying Z-axis drift of RLG based on GA-SVR model

This paper describes a novel approach for identifying the Z-axis drift of the ring laser gyroscope （RLG） based on ge-netic algorithm （GA） and support vector regression （SVR） in the single-axis rotation inertial navigation system （SRINS）. GA is used for selecting the optimal parameters of SVR. The latitude error and the temperature variation during the identification stage are adopted as inputs of GA-SVR. The navigation results show that the proposed GA-SVR model can reach an identification accuracy of 0.000 2 （？）/h for the Z-axis drift of RLG. Compared with the ra-dial basis function-neural network （RBF-NN） model, the GA-SVR model is more effective in identification of the Z-axis drift of RLG.     

系统可持续发展的评价模型构建——基于模糊语言值逻辑的近似推理方法

基于模糊语言值逻辑的近似推理评价方法能够在一定意义上克服可持续发展概念本身所具有的深刻模糊性及其实现的难度自增值性。该评价模型包括六个步骤：（1）确定系统可持续发展指标体系;（2）评价指标测量值的归一化处理;（3）语言变量及其语言值的选取;（4）模糊推理规则库的建立;（5）模糊推理过程;（6）逆模糊化过程。     

ECCM scheme against interrupted sampling repeater jammer based on time-frequency analysis

The interrupted sampling repeater jamming（ISRJ） is an effective deception jamming method for coherent radar, especially for the wideband linear frequency modulation（LFM） radar. An electronic counter-countermeasure（ECCM） scheme is proposed to remove the ISRJ-based false targets from the pulse compression result of the de-chirping radar. Through the time-frequency（TF） analysis of the radar echo signal, it can be found that the TF characteristics of the ISRJ signal are discontinuous in the pulse duration because the ISRJ jammer needs short durations to receive the radar signal. Based on the discontinuous characteristics a particular band-pass filter can be generated by two alternative approaches to retain the true target signal and suppress the ISRJ signal. The simulation results prove the validity of the proposed ECCM scheme for the ISRJ.     

Region-based classification by combining MS segmentation and MRF for POLSAR images

Speckle effects on classification results can be suppressed to some extent by introducing the contextual information.An unsupervised classification algorithm is proposed for polarimetric synthetic aperture radar(POLSAR) images based on the mean shift(MS) segmentation and Markov random field(MRF).First,polarimetric features are exacted by target decomposition for MS segmentation.An initial classification is executed by using the target decomposition and the agglomerative hierarchical clustering algorithm.Thereafter,a classification step based on MRF is performed by using the mean coherence matrices obtained for each segment.Under the MRF framework,the smoothness term is defined according to the distance between neighboring areas.By using POLSAR images acquired by the German Aerospace Centre and National Aeronautics and Space Administration/Jet Propulsion Laboratory,the experimental results confirm that the proposed method has higher accuracy and better regional connectivity than other classification methods.     

Survey on nonlinear reconfigurable flight control

An overview on nonlinear reconfigurable flight control approaches that have been demonstrated in flight-test or highfidelity simulation is presented. Various approaches for reconfigurable flight control systems are considered, including nonlinear dynamic inversion, parameter identification and neural network technologies, backstepping and model predictive control approaches. The recent research work, flight tests, and potential strength and weakness of each approach are discussed objectively in order to give readers and researchers some reference. Finally, possible future directions and open problems in this area are addressed.     

基于NCS改进SAR大斜视角RD成像算法

SAR在大斜视时距离向和方位向存在着严重的耦合,为了消除这种耦合,分析了一种基于非线性调频变标NCS的改进RD算法。它充分利用大斜视角回波信号的大距离走动、小距离弯曲的特点,首先在距离向校正距离走动,然后采用非线性调频变标NCS来补偿方位向调频率的空变性,最后通过几何校正完成目标成像。同时仿真模拟场景的原始回波信号并对改进后的算法进行仿真,仿真结果表明,该算法可有效补偿方位向调频率的空变性,具有较高的精度,满足大斜视角下的成像要求。

Abstract：

To eliminate the serious coupling between azimuth and range for SAR in large squint mode,an improved RD imaging algorithm based on nonlinear chirp scaling was proposed,which made full use of the characteristic of SAR echo signal in large squint mode,which featured large range walk and small range curvature.First,range walk was corrected.Second,nonlinear chirp scaling operation was adopted to compensate the azimuth-dependent chirp rate.Finally,geometry correction was used to correct geometric distortion.Meanwhile the raw echo signal of the scene and the improved algorithm was simulated.Simulation results illustrate that it efficiently compensates the azimuth-dependent chirp rate,possesses high precision and satisfies the imaging quality of SAR in large squint mode.     

Evidence for self-organized criticality in unscheduled downtime data of equipment

How to reduce downtime and improve availability of the complex equipment is very important. Although the unscheduled downtime（USDT） issues of the equipment are very complex, the self-organized criticality（SOC） is the right theory to study complex systems evolution and opens up a new window to the investigation of disasters, such as the sudden failure of the equipment. Firstly,SOC theory and its validation method are introduced. Then an SOC validation method for USDT of the equipment is proposed based on the above theory. Case study is done on bottleneck equipment in a factory and corresponding data pre-process work is done. The rescaled-range（R/S） analysis method is used to calculate the Hurst exponent of USDT time-series data in order to determine the long-range correlation of USDT data on time scale;at the same time the spatial power-law characteristic of USDT time series data is studied. The result shows that the characteristics of SOC are revealed in USDT data of the equipment according to the criterion of SOC. In addition, based on the characteristics of SOC,the overall framework of the prediction method for major sudden failure of the equipment is proposed based on SOC.     

Reduced K-best sphere decoding algorithm based on minimum route distance and noise variance

This paper focuses on reducing the complexity of K-best sphere decoding （SD） algorithm for the detection of uncoded multi-ple input multiple output （MIMO） systems. The proposed algorithm utilizes the threshold-pruning method to cut nodes with partial Euclidean distances （PEDs） larger than the threshold. Both the known noise value and the unknown noise value are considered to generate the threshold, which is the sum of the two values. The known noise value is the smal est PED of signals in the detected layers. The unknown noise value is generated by the noise power, the quality of service （QoS） and the signal-to-noise ratio （SNR） bound. Simulation results show that by considering both two noise values, the proposed algorithm makes an efficient reduction while the performance drops little.     

Reduced bit low power VLSI architectures for motion estimation

Low power and real time very large scale integration(VLSI) architectures of motion estimation(ME) algorithms for mobile devices and applications are presented.The power reduction is achieved by devising a novel correction recovery mechanism based on algorithms which allow the use of reduced bit sum of absolute difference(RBSAD) metric for calculating matching error and conversion to full resolution sum of absolute difference(SAD) metric whenever necessary.Parallel and pipelined architectures for high throughput of full search ME corresponding to both the full resolution SAD and the generalized RBSAD algorithm are synthesized using Xilinx Synthesis Tools(XST),where the ME designs based on reduced bit(RB) algorithms demonstrate the reduction in power consumption up to 45% and/or the reduction in area up to 38%.     

Evaluation matrix with the speed feature based on double inspiriting control lines

Methods of the comprehensive evaluation have been studied for many years. However, the change speed of evaluated objects was rarely considered by the existing evaluation methods. An evaluation matrix is proposed to remedy this deficiency. Firstly, the change speed state （CSS） of the evaluated objects is analyzed based on double inspiriting control lines （DICLs）, and a matrix of the CSS is constructed. Then, 72 elements in the matrix are analyzed, and formulas describing each CSS are given. The efficiency of the proposed evaluation matrix is proved when the CSS merges with the change speed trend （CST） in the dynamic comprehensive evaluation. Finally, a computing example shows that the proposed evaluation matrix is feasible in the dynamic comprehensive evaluation with the speed feature.