Loop-Shaping Based Control for Switch Mode DC-DC Power Converters

Renewable energy sources require switching regulators as an interface to a load with high efficiency, small size, proper output regulation, and fast transient response. Moreover, due to the nonlinear behavior and switching nature of DC-DC power electronic converters, there is a need for high-performance control strategies. This work summarized the dynamic behavior for the three basic switch-mode DC-DC power converters operating in continuous conduction mode, i.e. buck, boost, and buck-boost. A controller was designed using loop-shaping based on current-mode control that consists of two feedback loops. A high-gain compensator with wide bandwidth was used in the inner current loop for fast transient response. A proportional-integral controller was used in the outer voltage loop for regulation purposes. A procedure was proposed for the parameters of the controller that ensures closed-loop stability and output voltage regulation. The design-oriented analysis was applied to the three basic switch-mode DC-DC power converters. Experimental results were obtained for a switching regulator with a boost converter of 150 W, which exhibits non-minimum phase behavior. The performance of the controller was tested for voltage regulation by applying large load changes.

植物响应盐碱胁迫的分子机制研究进展

土壤盐碱化是制约全球农业发展的主要环境因素之一。培育耐盐碱作物是应对土壤盐碱化的根本措施,但目前仍面临基因、种质资源匮乏等挑战。挖掘耐盐碱新基因,阐明植物耐盐碱应答的分子机制对培育耐盐碱作物至关重要。盐碱胁迫包括中性盐胁迫和碱性盐胁迫,中性盐胁迫会产生渗透胁迫,Na~+、Cl~-积累过量还会导致离子毒害,引起氧化胁迫等一系列次生胁迫。与中性盐胁迫相比,碱性盐胁迫还会引起高pH胁迫。论文综述了盐碱胁迫对植物生长发育的影响,总结了近十年植物耐盐碱应答机制的重要研究进展。包括植物对盐胁迫的感知与信号转导,以及植物响应中性盐胁迫和碱性盐胁迫引起的渗透胁迫、离子毒害、氧化胁迫、碳酸氢盐和碳酸盐胁迫、高pH胁迫的分子机制。在此基础上,还讨论了耐盐碱基因在作物育种方面的应用,并提出了提高植物耐盐碱性需要进一步研究的关键科学问题。旨在加深对植物响应盐碱胁迫分子机制的认识,为培育高产、优质的耐盐碱品种及提升盐碱地可开发利用率提供理论基础。

非标准H~∞控制系统结构的研究

研究了具有无穷远零点的非标准四块Ｈ∞控制系统的结构，证明了通过弓引入适当的假想被测量信号和控制信号，可将四块Ｈ∞控制的求解问题等价为一块Ｈ∞控制的求解问题。对于增广得到的一块Ｈ∞控制问题，本文证明了其广义对象的散射模型具有Ｊ－无损分解，且其中的单模矩阵因子是上三角的，此结构保证了假想被测量信号和控制信号不被利用。本文还进一步分析和揭示了Ｈ∞控制系统的无损性和对偶性。

H~∞ Theory and its Application to the Position of Rolling Mill Control System

The controller designed according to classical or modern control theory will not satisfy the performance requirements when the controlled object in industrial field can not be described by exact mathematical model or the disturbance of the controlled system. In order to make the controlled system stable and having good performance, H∞ control theory was put forward to solve this practical problem. Taking the position of a rolling mill as the controlled object, it was rectified by optimal engineering way. Then, three different plans were put forward according to Bang-Bang control, LQ control and H∞ control, respectively. The result of the simulation shows that the controller designed according to H∞ method whose robust performance and ability to restrain colors disturbance is satisfactory.

基于H^∞滤波的阵列互耦及通道幅相误差联合自校正算法

针对非理想均匀阵列中存在的模型误差（通道幅相不一致及阵元间互耦）提出一种联合自校正算法。该算法利用鲁棒控制理论中的H^∞滤波方法,在阵列模型误差较大时为对初始值要求严格的交替迭代寻优技术提供稳健的DOA估计,在校正阵列模型误差的同时得到更精确的DOA估计值。理论分析和仿真结果均表明该算法增大了自校正技术对阵列模型误差的校正范围,具有良好的工程应用前景。

DC-DC Boost变换器控制算法的研究

为了改善DC-DC Boost变换器的性能,在电压控制模式的基础上,设计了PI控制器,对输出电压进行控制。分析了DC-DC Boost变换器的基本原理,推导了变换器的传递函数。本文用Ziegler-Nichols方法和Loop-Shaping方法计算出PI控制器中Kp和Ki的值,进而通过Matlab仿真和实验,比较了两种方法的输出响应,得出结论:采用Loop-Shaping方法能更好改善变换器的性能。

Kantorovic变形算子的保形性质

讨论了Kantorovic变形算子的保形性质,得到Kantorovic变形算子具有单调性,并且有保上凸性、保Hω类性和保连续模性.

关联大系统鲁棒跟踪器的设计

针对关联大系统，采用一种处理大系统各子系统间关联项的新方法及内模原理，在时域中给出了Ｈ∞鲁棒跟踪器的设计方法。仿真结果表明，该方法设计出的跟踪器对外加扰动的鲁棒性较强。

关联大系统的分散开环回路传递再生

基于Ｈ∞理论和分散状态观测器，提出了不确定性关联大系统的分散开环回路传递再生方法．给出了满足开环再生矩阵Ｈ∞范数要求的观测器的存在性．在大系统关联项块对角奇异值分解的基础上，证明了通过解Ｒｉｃｃａｔｉ方程可以求得使开环再生差阵满足要求的分散观测器增益阵，以实现分散开环传递再生．试验结果表明，分散开环回路传递再生控制性能与分散状态反馈控制性能基本相同．

水稻穗顶部退化突变体tutou3的基因精细定位

水稻穗顶部退化在水稻生产中时有发生,影响水稻的穗粒数,严重时会导致水稻产量下降。目前,虽然从水稻穗顶部退化突变体中已经鉴定出了一些基因如PAA1、PAA2、TUT1等,但是对穗顶部退化发生的分子机制的认知仍十分有限。本研究报道了一个穗顶部退化的隐性突变体tutou3的基因定位及克隆结果。该突变体在营养生长时期表现为株高变矮,穗发育后期穗顶部发生严重退化,每穗实粒数、穗长、千粒重极显著降低。遗传分析表明,tutou3受1对隐性基因控制。利用tutou3×IRAT129杂交组合F2分离群体中的856个穗顶部退化极端个体,将基因TUTOU3定位在了4号染色体长臂端的29 kb区间内,测序研究发现,区间内一个编码质膜H+-ATP酶基因LOC_Os04g56160的第8外显子存在1个C→A单碱基替换,导致第608个氨基酸从丙氨酸突变为天冬氨酸。qRT-PCR分析发现,TUTOU3基因在水稻中呈组成型表达,在突变体中该基因表达量下降。诱发穗顶部细胞程序性死亡的基因OsVPE2和OsVPE3在突变体tutou3中表达量极显著上升。对TUTOU3基因的深入研究将会揭示H+-ATP酶在穗顶部细胞的生长发育中的作用,有助于深入阐明穗顶部退化在细胞水平上发生的机制。

Autopilot Control Synthesis for Path Tracking Maneuvers of Underwater Vehicles

This paper is concerned with the robust control synthesis of autonomous underwater vehicle （AUV） for general path following maneuvers. First, we present maneuvering kinematics and vehicle dynamics in a unified framework. Based on H∞ loop-shaping procedure, the 2-DOF autopilot controller has been presented to enhance stability and path tracking. By use of model reduction, the high-order control system is reduced to one with reasonable order, and further the scaled low-order controller has been analyzed in both the frequency and the time domains. Finally, it is shown that the autopilot control system provides robust performance and stability against prescribed levels of uncertainty.

Disturbance Attenuation State-Feedback Control for Uncertain Interconnected Systems

This paper studies the problem of robust H∞ control design for a class of uncertain interconnected systems via state feedback. This class of systems are described by a state space model, which contains unknown nonlinear interaction and time-varying norm-bounded parametric uncertainties in state equation. Using the Riccati-equation-based approach we design state feedback control laws, which guarantee the decentralized stability with disturbance attenuation for the interconnected uncertain systems. A simple example of an interconnected uncertain linear system is presented to illustrate the results.

Synthesis of Fractional-order PI Controllers and Fractional-order Filters for Industrial Electrical Drives

This paper introduces an electrical drives control architecture combining a fractional-order controller and a setpoint pre-filter. The former is based on a fractional-order proportional-integral(PI) unit, with a non-integer order integral action, while the latter can be of integer or non-integer type. To satisfy robustness and dynamic performance specifications, the feedback controller is designed by a loop-shaping technique in the frequency domain. In particular, optimality of the feedback system is pursued to achieve input-output tracking. The setpoint pre-filter is designed by a dynamic inversion technique minimizing the difference between the ideal synthesized command signal(i.e., a smooth monotonic response) and the prefilter step response. Experimental tests validate the methodology and compare the performance of the proposed architecture with well-established control schemes that employ the classical PIbased symmetrical optimum method with a smoothing pre-filter.

周视镜系统中的鲁棒伺服控制器

用H~∞控制理论设计伺服控制器,具有频谱直接定型的优点,但是经典的H~∞控制器是以最大最小原则来求解,即考虑到外部输入(包含伺服控制器所要跟踪的控制指令)为最恶劣的情况求取输出最小的控制解。工程应用中,控制指令往往不是最恶劣的输入,若将控制指令建模,将不确定的控制指令变为确定性输入,能改善H~∞控制器的性能指标。由于控制指令难以固定模型建模,本文合理假定控制指令为分段可微,对控制指令进行部分建模为积分环节,求出H~∞控制器不仅具有反馈结构,还具有指令前馈结构,并改善了跟踪性能。另外,本文以工程实例,讨论如何应用输出加权阵的选取来对系统进行频谱定型,以及装置不确定性的测量等工程设计中的技术关键,这些都具有一定参考价值。

INTERPOLATION SPACES BETWEEN H^1 AND L~∞ ON SPACES OF HOMOGENEOUS TYPE

Using the maximal function characterization of Hardy spaces, we study the interpolation spaces between H1 and L∞ on spaces of homogeneous type.

REGULARITY OF H^1 ∩L^(n((γ-1)/(2-γ))) WEAK SOLUTIONS FOR NONLINEAR ELLIPTIC SYSTEMS

Let us consider the following elliptic systems of second order-D_α(A_i~α(x, u, Du))=B_4(x, u, Du), i=1, …, N, x∈Q(?)R^n, n≥3 (1) and supposeⅰ) |A_i~α(x, u, Du)|≤L(1+|Du|);ⅱ) (1+|p|)^(-1)A_i~α(x, u, p)are H(?)lder-continuous functions with some exponent δ on (?)×R^N uniformly with respect to p, i.e.ⅲ) A_i~α(x, u, p) are differentiable function in p with bounded and continuous derivativesⅳ)ⅴ) for all u∈H_(loc)~1(Ω, R^N)∩L^(n(γ-1)/(2-γ))(Ω, R^N), B(x, u, Du)is ineasurable and |B(x, u, p)|≤a(|p|~γ+|u|~τ)+b(x), where 1+2/n<γ<2, τ≤max((n+2)/(n-2), (γ-1)/(2-γ)-ε), (?)ε>0, b(x)∈L2n/(n+2), n^2/(n+2)+e(Ω), (?)ε>0.Remarks. Only bounded open set Q will be considered in this paper; for all p≥1, λ≥0, which is clled a Morrey Space.Let assumptions ⅰ)-ⅳ) hold, Giaquinta and Modica have proved the regularity of both the H^1 weak solutions of (1) under controllable growth condition |B|≤α(|p|~γ+|u|^((n+2)/(n-2))+b, 0<γ≤1+2/n and the H^1∩L~∞ weak solutions of (1) under natural growth condition |B|≤α|p|~2+b with a smallness condition 2aM<λ(|u|≤M), which implys that the H^1∩L~∞ weak solutions have the same regularty in the case of 1+2/n<γ<2. In the case of γ=2, many counterexamples (see [2] showed that u must be in H^1L~∞, while in the case of 1+2/n<γ<2, we consider the H^1∩L^n(γ-1)/(2-γ) weak solutions of (1), weaken the instability conditions upon them (from L~∞ to L^n(γ-1)/(2-γ) and obtain the same regularity results. Finally we show that the exponent n(γ-1)/(2-γ) can not be docreased anymore for the sake of the regularity results.Delinition 1. We call u∈H^1∩L^n(γ-1)/(2-γ)(Q, R^N) be a weak solution of (1), providod that where We use the convention that repeated indices are summed. i, j go from 1 to N ann α, β from 1 to n.

电罗经航向的H~∞跟踪估计方法研究

为提高在风、流、摇摆等众多外界干扰下电罗经航向输出的精确度,提出了基于H~∞的航向跟踪估计方法。简要介绍了H~∞估计理论,基于H~∞估计理论对最速跟踪微分器进行一步改进设计,构造误差反馈矩阵,实现最速跟踪微分器的在线反馈控制,获得较为理想的效果,为减小电罗经航向误差及提高航行安全提供一种行之有效的方法。

Pressure-tuning domain-wall chirality in noncentrosymmetric magnetic Weyl semimetal CeAlGe

Topological magnetic Weyl semimetals have been proposed to host controllable chiral domain walls which bear a great prospect in device applications. To exploit them in applications, it is important to have a proper way to tune and manipulate these domain walls. One possible means is through magnetoelastic coupling. The involvement of rare earth in the lately proposed RAl X(R =rare earth, X = Si and Ge) family magnetic Weyl semimetals may provide such a platform. Here we present the transport and thermodynamic properties of Ce Al Ge under hydrostatic pressure. We find that pressure enhances the antiferromagnetic exchange in Ce Al Ge but essentially retains its magnetic structure. A large topological Hall effect with a pronounced loop shape is observed within the magnetically ordered state, and it splits into two regions under pressure. Such an unusual electromagnetic response is inferred to be a consequence of chiral magnetic domain walls. The unprecedented concomitance of its evolution under pressure and the reentrance of antiferromagnetic order strongly suggest the capability of switching on/off this electromagnetic response in noncentrosymmetric magnetic Weyl semimetals via magnetoelastic coupling.

Dynamic modeling and H_∞ independent modal space vibration control of laminate plates

In this paper, combining the transfer matrix method and the finite element method, the modified finite element transfer matrix method is presented for high efficient dynamic modeling of laminated plates. Then, by constructing the modal filter and the disturbance force observer, and using the feedback and feedforward approaches, the H ∞ independent modal space control strategy is designed for active vibration control of laminate plates subjected to arbitrary, immeasurable disturbance forces. Compared with ordinary dynamic modeling and control methods of laminated plate structures, the proposed method has the low memory requirement, high computational efficiency and robust control performance. Formulations as well as some numerical examples are given to validate the method and the control performance.

Maize ZmVPP5 is a truncated Vacuole H^＋-PPase that confers hypersensitivity to salt stress

In plants, Vacuole H^＋-PPases（VPPs） are important Aproton pumps and encoded by multiple genes. In addition to full-length VPPs, several truncated forms are expressed, but their biological functions are unknown. In this study, we functionally characterized maize vacuole H^＋-PPase 5（ZmVPP5）, a truncated VPP in the maize genome. Although ZmVPP5 shares high sequence similarity with ZmVPP1 ZmVPP5 lacks the complete structure of the conserved proton transport and the inorganic pyrophosphatase-related domain. Phylogenetic analysis suggests that ZmVPP5 might be derived from an incomplete gene duplication event. ZmVPP5 is expressed in multiple tissues, and ZmVPP5 was detected in the plasma membrane, vacuole membrane and nuclei of maize cells. The overexpression of ZmVPP5 in yeast cells caused a hypersensitivity to salt stress. Transgenic maize lines with overexpressed ZmVPP5 also exhibited the salt hypersensitivity phenotype. A yeast two-hybrid analysis identified the ZmBag6 like protein as a putative ZmVPP5-interacting protein. The results of bimolecular luminescence complementation（Bi LC）assay suggest an interaction between ZmBag6-like protein and ZmVPP5 in vivo. Overall, this study suggests that ZmVPP5 might act as a VPP antagonist and participate in the cellular response to salt stress. Our study of ZmVPP5 has expanded the understanding of the origin and functions of truncated forms of plant VPPs.