MPPT算法与输入输出反馈线性化控制技术在光伏发电系统中的应用

针对目前光伏发电系统采用的固定电压法、增量电导法等最大功率点跟踪控制技术跟踪速度慢、精度不佳的问题,提出采用变步长电导增量法进行最大功率点跟踪控制;为了控制光伏系统中电网电流和直流母线电压,采用输入输出反馈线性化控制技术,使得系统的功率因数和直流母线电压可用相同的算法进行控制。在Matlab/Simulink环境下对基于变步长电导增量法算法与输入输出反馈线性化控制技术的光伏发电系统进行了建模仿真,结果表明,采用反馈线性化技术控制逆变器后,日照强度和温度变化不会对电网功率因数产生影响;变步长电导增量法提高了光伏发电系统的动态和稳态性能,且降低了电网电流的总谐波失真率。     

一种改进的邻接关系可查询压缩算法

目前多数数据压缩算法不能直接在压缩结果上进行数据查询,大数据的线性化压缩算法虽然可直接在压缩后的数据上进行邻接关系查询,但压缩率较低.针对该问题,对线性化压缩的实现原理进行研究,分析MPk线性化算法在不同社会网络样本下的压缩效率,发现线性化压缩结果中存在冗余信息,并针对该情况设计改进算法,删去原有数据结构中的冗余部分,进一步提高压缩率.实验结果证明,改进算法的时间复杂度与原算法相同,压缩率平均提升23％.     

一种锅炉系统模型分析及其非线性控制

文中从控制系统设计的角度，对锅炉系统模型进行全面分析，并应用非线性控制方法，解决大范围、全工况、多扰动优化运行。首先分析线性化模型的可控可观性、非最小相位特性、基于相对增益矩阵的耦合性、配对策略和基于相对非线性测度的非线性度等，认为该非线性锅炉模型是控制器设计和控制算法评价的标准问题；然后给出状态反馈线性化设计步骤、控制系统结构和鲁棒稳定性的理论保证；最后，仿真验证该非线性控制策略具有良好的设定值跟踪性能，对外扰和负荷扰动以及参数摄动均具有鲁棒性。     

一种基于LINC发射机系统的信号分离实现方法

LINC发射机是使用非线性但是高效率的射频功率放大器来实现信号的线性放大。在LINC系统中,信号分离部分(SCS)是LINC系统中非常重要的信号处理过程,直接影响LINC系统线性度及效率的提高。对目前存在的几种信号分离实现方法就占用逻辑资源、运行速度等方面进行比较后,采用了一种优化实现方法,并对信号分离部分及LINC系统做出了仿真论证,完成了LINC线性高效功率放大。     

机械摆供货系统的反馈机构设计计算

提出了机械摆供货系统的机械反馈机构参数转换计算方法,并列出了参数转换函数表达式,为反馈机构的设计提供了可靠的数据保证,在解决机械摆随机同步跟踪俯仰机构问题时具有明显的优越性.     

FPGA Implementation of a Power Amplifier Linearizer for an ETSI-SDR OFDM Transmitter

Most satellite digital radio （SDR） systems use orthogonal frequency-division multiplexing （OFDM） transmission, which means that variable envelope signals are distorted by the RF power amplifier （PA）. It is customary to back off the input power to the PA to avoid the PA nonlinear region of operation. In this way, linearity can be achieved at the cost of power efficiency. Another attractive option is to use a linearizer, which compensates for the nonlinear effects of the PA. In this paper, an OFDM transmitter conforming to European Telecommunications Standard Institute SDR Technical Specifications 2007-2008 was designed and implemented on a low-cost field-programmable gate array （FPGA） platform. A weakly nonlinear PA, operating in the L-band SDR frequency, was used for signal transmission. An adaptive linearizer was designed and implemented on the same FPGA device using digital predistortion to correct the undesired effects of the PA on the transmitted signal. Test results show that spectral distortion can be suppressed between 6-9 dB using the designed linearizer when the PA is driven close to its saturation region.     

使用自适应RF预失真技术改善放大器线性的研究

RF功率放大器对信号造成的非线性失真会产生邻道干扰，并降低信号质量，因此宽带通信系统对功率放大器的线性提出了严格的要求。本文提出了可以改善功率放大器线性的自适应RF预失真电路的模型，描述了自适应RF预失真的实现过程；介绍了现有的一些自适应预失真技术，具体分析了常用的矩形功函数预失真技术和最小功率自适应方法；通过仿真进一步证明了预失真技术可大大提高RF功率放大器的线性度。     

水下滑翔机建模与运动PID控制

水下滑翔机是一种浮力驱动的新型水下航行器,其特殊的驱动方式和结构特点增加了建模和控制分析的复杂度。为获得准确有效的水下运动控制方法,本文通过滑翔机运动学和动力学分析,建立了较为完善的3D空间数学模型,并进行了合理的假设和简化,得到纵平面内小扰动线性化模型。在此基础上,设计了比例积分微分（PID）控制器。并针对滑翔机的纵平面运动进行了仿真分析,结果显示,PID控制器有很好的干扰抑制能力和跟踪性能,由此也验证了纵平面内滑翔机的运动特性。     

永磁同步电机负载扰动控制器设计

提出了永磁同步电机反馈线性化和极点配置的观测器控制方案,达到了线性化控制的目的,减小了负载扰动对转矩的影响。通过仿真,证明了该方法的有效性。     

Self-adaptive systems: A survey of current approaches,research challenges and applications

Self-adaptive software is capable of evaluating and changing its own behavior, whenever the evaluation shows that the software is not accomplishing what it was intended to do, or when better functionality or performance may be possible. The topic of system adaptivity has been widely studied since the mid-60s and, over the past decade, several application areas and technologies relating to self-adaptivity have assumed greater importance. In all these initiatives, software has become the common element that introduces self-adaptability. Thus, the investigation of systematic software engineering approaches is necessary, in order to develop self-adaptive systems that may ideally be applied across multiple domains. The main goal of this study is to review recent progress on self-adaptivity from the standpoint of computer sciences and cybernetics, based on the analysis of state-of-the-art approaches reported in the literature. This review provides an over-arching, integrated view of computer science and software engineering foundations. Moreover, various methods and techniques currently applied in the design of self-adaptive systems are analyzed, as well as some European research initiatives and projects. Finally, the main bottlenecks for the effective application of self-adaptive technology, as well as a set of key research issues on this topic, are precisely identified, in order to overcome current constraints on the effective application of self-adaptivity in its emerging areas of application.