基于未知输入观测器的车载炮电液位置伺服系统故障检测

针对车载炮电液位置伺服系统在运行时存在大惯量、负载非线性、参数不确定性和干扰等特点,提出一种基于非线性未知输入观测器的故障检测方案。在对系统建模后进行观测器设计,借助李雅普诺夫稳定性理论证明观测器稳定性并给出了存在条件,观测器产生用于故障检测的残差信号。在故障检测台上在线检测观测器的观测能力以及对故障的检测能力,设计了基于统计的动态阈值故障决策机制,消除了固定阈值在过渡阶段系统出现的误报警现象。实验结果表明：所提出的故障检测方案有效,可用于电液位置伺服系统在线故障的检测。     

Harmonic fold back reduction at the N‐path filters

In this paper, a method is proposed to reduce harmonic fold back (HFB) problem of N‐path filters, without increasing the input reference clock (f_CLK ) frequency. The HFB at the N‐path filter is analyzed, and simple expressions are extracted to model this problem. Using the results of the analysis, an M‐of‐N‐path filter has been proposed that behaves like an M × N‐path filter in terms of HFB problem; however, the f_CLK frequency of this structure is the same as an N‐path filter. To demonstrate the feasibility of the proposed idea, a 3‐of‐4‐path filter is designed, and its characteristics are compared with 4‐path and 12‐path filters by simulation. Impacts of different non‐idealities like clock‐phase error, mismatch, and parasitic capacitance are investigated. The transistor‐level implementation of this filter is performed in 0.18 µm Complementary Metal Oxide Semiconductor (CMOS) technology. The simulation results show that the filter has the pass‐band gain of 17 dB, tuning range of 0.2–1.2 GHz, −3 dB bandwidth of 25 MHz, quality factor of 8–48, 18 dB out‐of‐band rejection, 16 dB rejection of the third harmonic of switching frequency (f_s ), and the noise figure of 4.35 dB (using ideal G_m cells) and 6.95 dB (for practical G_m cells). The strongest harmonic folding to the filter pass‐band occurs around 11f_s with the attenuation of 23.8 dB. Each G_m cell draws about 12.4 mA from 1.8 V supply, and the out‐of‐band IIP3 and P _{1 dB,CP} are 17 and 4 dBm, respectively. Copyright © 2016 John Wiley & Sons, Ltd.     

Revisited generalized substitution theorem and its consequences for circuit analysis

The Substitution Theorem (ST) is generally perceived as a mere theoretical curiosity. In this paper, a formerly derived generalized ST (GST) is carefully revised, which leads to both a Weak Revisited GST (RGST) and a Strong RGST (characterized by noticeably relaxed hypotheses with respect to the GST). Then, despite the common opinion about the ST, such RGSTs are showed to be powerful analytical tools to generalize, make rigorous and rigorously prove several classic results of Circuit Theory, namely: the Substitution Theorem for Multiterminal Circuits, the Source‐Shift Theorem, the Thévenin–Norton Theorem, the Miller Theorem alongside its Dual, and the Augmentation Principle. More specifically, the Substitution Theorem for Multiterminal Circuits is extended to an arbitrary set of sources, possibly including nullors. The Source‐Shift Theorem is rigorously derived, and possible related ambiguities are removed. Also, all possible hybrid forms of the Thévenin–Norton Theorem for multiports are individuated, and a precise operative procedure for calculating the relevant entities is provided for all cases. Furthermore, the Miller Theorem and its Dual are extended to an arbitrary number of variables and to multiports. As to the Augmentation Principle, the constraint regarding the linearity of the augmenting resistors is removed. Finally, thoroughly worked examples are given in which the aforementioned noteworthy consequences of the RGSTs are proved to be efficient tools for analysis by inspection of linear and nonlinear circuits. Among the other things, systematic pencil‐and‐paper procedures for DC‐point and input‐output (or driving‐point) characteristic calculation in nonlinear networks are derived and applied to circuits with considerably complex topology. Copyright © 2016 John Wiley & Sons, Ltd.     

Decentralized bounded input bounded output stabilization of perturbed interconnected time-delay power systems with energy storages

This paper presents a new decentralized bounded input bounded output (BIBO) stabilization problem for a class of interconnected time-delay systems and its application to power systems with energy storages. We first provide conditions for the derivation of an ellipsoid that bounds a given linear functions of the state vector. Then, a design procedure is proposed to synthesize decentralized static output feedback controllers. The designed controllers guarantee that a given linear functions of the state vector, starting from any initial condition, converges exponentially to its prescribed zones. To deal with the time-delay issue, we use an improved weighted integral inequality recently reported in the literature to derive less conservative exponential stability conditions. Then, our presented control approach is applied to an interconnected power system integrated energy storages with multiple time delays. We synthesis decentralized static output feedback load frequency controllers to guarantee that the system frequency and interchanged power converge to their prescribed zones exponentially from any initial conditions. The controller’s construction is simpler and easier for implementation due to only the local output measurements are required. In order to systematically obtain the controller gains, an effective procedure using linear matrix inequality based stabilisation criteria, which can be solved by various computation tools, is provided. Finally, the effectiveness of the proposed control scheme is verified by comprehensive simulations.     

Sepic变换器直接电流控制

基于李亚普诺夫直接法和输入输出线性化控制法,提出了一种新型Sepic变换器直接电流控制策略。建立了Sepic变换器单输入单输出仿射非线性系统模型。采用李亚普诺夫直接法,建立了Sepic变换器李亚普诺夫直接法控制系统。在李亚普诺夫直接法的基础上提出了一种直接电流控制方法,通过直接控制电感电流,间接获得期望的输出电压。比较分析发现该直接电流控制法比李亚普诺夫直接法控制结构更简单,控制代价更低,易于数字实现。数值仿真和实验结果验证了所提控制策略的正确性和优越性。基于所提控制方法的系统输出无稳态误差,并对负载扰动具有较强的鲁棒性。     

车载显控终端输入方式对乘员信息处理能力影响试验研究

基于自主开发的车载显控终端作业模拟及工效测试系统,以任务完成时间和错误率为考核指标,通过作业模拟方式,以研究触屏和鼠标两种输入方式对乘员信息处理能力的影响为试验目的进行了试验。研究结果表明:所采用的研究方法可有效区分不同输入方式对乘员信息处理能力的影响,实际作业绩效考核应以触屏操作的绩效考核指标为准;但从掌握系统操作功能来看,两种输入方式的训练效果相同。该研究结果可为车载显控终端输入方式的遴选,人员科学训练提供借鉴和参考。     

北京市生态足迹动态变化研究

构建基于投入产出技术的生态足迹模型对北京市2005年与2010年的生态足迹进行了对比分析。北京市生态足迹虽有所下降,但仍然处于不可持续状态。在方法上将生态足迹划分为市内、市外和国外生态足迹3个部分,研究得出市内需求占用生态足迹最多,2010年政府消费支出和固定资本形成所占用的生态足迹比重分别上升了9%和5%,农村居民消费和存货调整占用的生态足迹比重下降了14%和1%。在结果上,从产业、需求的角度来分析北京市39个产业和3个区域生态足迹变化对北京市生态足迹总量变化的影响,计算分析得出农林牧渔业、石油加工炼焦及核燃料加工业、交通运输仓储业及邮政业和其他服务业占用生态足迹较多。     

基于DSC和MCU的多输入多功能特种电源的研究

研究设计了一款多输入多功能特种电源,该电源以数字信号控制器(DSC)MC56F8037和微控制单元(MCU)MC9S12G48为控制核心,可将交流和直流输入电转换为满足特种车辆起动、供电、焊接及蓄电池充电所需的直流电,具有技术先进、安全性高、可靠性好、环境适应性强等优点。     

一种单级高频AC-AC变换器的低通输入滤波器的参数设计

单级高频AC-AC变换器将工频电网电压转换为高频(一般大于100k Hz)正弦交流电压,并实现功率因数校正的功能。由于其功率因数校正单元工作于电流断续模式(DCM),使得输入电流含有大量高次谐波,需采用低通输入滤波器予以滤除。上述低通输入滤波器的滤波参数不仅影响其滤波性能,还会影响到输入功率因数等诸多方面,因此滤波参数的确定十分重要。首先,根据叠加定理分别建立变换器交流侧等效电路模型,即工频分量和开关频率分量单独作用下的等效电路;进而,根据滤波器输入、输出要求合理设置相关预设参数,使加入滤波器后电网输入侧满足能量之星关于功率因数的要求。在此基础上以LC低通输入滤波器为例,对输入滤波器参数的定量设计过程进行详细阐述,并归纳出一种程序化的设计方法;最后,进行仿真及实验验证设计方法的正确性,该方法也可用于单级有源功率校正器的输入滤波器设计,而且对设计其他类型的低通输入滤波器有借鉴价值。     

基于变量选择与高斯过程回归的短期负荷预测

提高短期电力负荷预测精度是保障电网安全稳定运行的技术措施之一,通过选取影响负荷的最优输入变量集合,建立高斯过程回归(Gaussian process regression,GPR)短期负荷预测模型。负荷预测建模输入变量的选取对预测精度有很大影响,首先采用随机森林(random forest,RF)算法给出输入变量重要性评分(variable importance measure,VIM),并对各输入变量影响程度进行排序,基于序列前向搜索策略确定最优输入变量集合,避免人工经验选取的不足。其次针对共轭梯度(conjugate gradient,CG)法求解高斯过程回归模型超参数时易陷入局部最优解,且存在优化性能依赖于初值选取、迭代次数难以确定的问题,采用改进粒子群优化(particle swarm optimization,PSO)算法搜索模型超参数,形成优化高斯过程回归预测模型。最后,算例测试表明该模型的有效性。