Controllability of differential inclusions

We consider autonomous differential inclusions on compact Riemannian manifolds and characterize regions of complete controllability, the so-called control sets. Therefore we introduce appropriate dynamical systems and relate control sets to minimal sets. we get robustness and continuity results for control sets under perturbation of the attainable set semiflow. The results are applied to nonlinear singularly perturbed control systems.     

Design and control of a PEMFC powered electric wheelchair

This paper proposes the design and control of a fuel-cell powered wheelchair. Electric wheelchairs can improve moving ability for people with walking problems. However, their traveling distances are limited by the capacity of their batteries. We designed a fuel-cell powered electric wheelchair that can be continuously operated, thereby extending the moving range. The system consisted of three subsystems: a commercial electric wheelchair, a proton exchange membrane fuel cell (PEMFC), and two secondary battery sets. The study was carried out in three parts, investigating the fuel-cell control, power management, and system integration. First, we designed multivariable robust controllers for a 500 W PEMFC system to charge the battery sets by constant voltage/current. Second, we designed a serial power management system, where the wheelchair motors were directly driven by the secondary battery sets, which in turn were charged by the PEMFC when their capacities dropped below a certain level. Lastly, we integrated the three subsystems and verified the system performance by experiments. The results confirmed the effectiveness of the PEMFC system as a way to extend the traveling distance of a motorized wheelchair.     

The development of an exchangeable PEMFC power module for electric vehicles

This paper develops an exchangeable fuel-cell power module that is replaceable on different light electric vehicles (LEVs). The module consists of a proton exchange membrane fuel-cell (PEMFC) and two battery sets, which provide continuous power for LEVs. The study includes three topics: fuel-cell control, power management, and system modularization and vehicle integration. First, we design robust controllers for the PEMFC to provide a steady voltage or current for charging the battery sets. Second, we develop a serial power train that can provide continuous power for driving the vehicle motors. Third, we modularize a power system that can be easily implemented on different LEVs. We build the system on Matlab™ SimPowerSystem for simulation before road tests, and integrate the power module onto a mobility car and an electric motorbike for experimental verification. Based on the results, the proposed systems are deemed effective.     

Regular Elements and Global Controllability in SL(d, R)

We introduce a generalized concept of split-regular elements and study the dynamics of such elements on the flag manifolds corresponding to the Lie group SL(d, R). Based on these concepts, we obtain the stable and unstable manifolds, the Morse decomposition, and obtain the limit sets inside the corresponding control sets. These dynamical aspects are studied with the purpose of applying them in order to extend a result of global controllability of discrete-time bilinear systems defined by elements of sl(d, R).     

The Structure of Reachable Sets and Geometric Optimality of Singular Trajectories for Certain Affine Control Systems in ℝ3. The Sub-Lorentzian Approach

In this paper, we investigate the structure of reachable sets from a given point q ₀ for a class of analytic control affine systems characterized, among other things, by possessing two singular trajectories initiating at q ₀. The aim of the paper is to establish the connection between the minimal number of analytic functions needed for describing reachable sets and the number of geometrically optimal singular trajectories. The paper is written in a language of the sub-Lorentzian geometry. Also, the sub-Lorentzian geometry methods are used to prove theorems.     

Hyperbolic Control Sets and Chain Control Sets

A shadowing lemma for hyperbolic control flows is proved. A consequence is that hyperbolic chain control sets are closures of control sets.     

On regularity properties of extremal controls

We prove some regularity properties of the optimal controls for the smooth bracket generating systems with scalar control parameters, and show that the Cantor sets cannot be the sets of switching points.Partially supported by the Russian Fund for Fundamental Research and grant No. 95-01-00310a.     

基于分频控制的微电网储能变流器并网电能质量主动控制策略

阐述了基于锁相环误差补偿的谐波无功电流检测及多目标电流的生成方法,并提出一种基于分频控制的微电网并网电流电能质量主动提升控制策略,结合比例谐振(PR)控制器所具有的频率选址特性,实现了对特定次频率分量的零稳态误差控制,利用储能交流器(PCS)剩余容量快速并精确的选择性补偿谐波和无功电流,在此基础上,PCS模糊PR控制根据模糊规则表在线调整并整定了PR比例和积分参数,进而有效实现了对PCS的分频控制,提高了对电能质量治理的响应速度和控制精度,最后,搭建含储能装置的微电网并网运行平台开展相关实验测试,验证了所提控制策略的正确性和有效性。     

DCS在多台电炉控制中的开发和应用

DCS是集中管理份散控制的一种控制技术,广泛应用于工业自动化生产.在此基础上,开发了小型DCS控制多台电炉,提高了工厂集中管理水平和产品质量.     

包含控制系统的烟气脱硫系统可靠性分配

提出了包含控制系统的完整烟气脱硫系统可靠性分配模型,并利用拉格朗日乘数法,对系统内各设备及相应控制系统进行可靠性优化分配.该方法解决了当前一直处于瓶颈阶段的经典方法求解包含控制系统的复杂成套装置系统可靠性分配问题.该方法对于和烟气脱硫系统相似的成套装置混联系统同样适用,具有一定的工程运用价值和借鉴意义.     

Modelling changes to electricity demand load duration curves as a consequence of predicted climate change for Australia

In this paper, we describe a method for constructing regional electricity demand data sets at 30 min intervals, which are consistent with climate change scenarios. Specifically, we modify a commonly used linear regression model between regional electricity demand and climate to also describe intraday variability in demand so that regional load duration curves (LDCs) can be predicted. The model is evaluated for four different Australian states that are participants in the Australian National Electricity Market (NEM) and the resultant data sets are found to reproduce each state's LDCs with reasonable accuracy. We also apply the demand model to CSIRO's Mk 3 global climate model data sets that have been downscaled to 60 km resolution using CSIRO's conformal-cubic atmospheric model to estimate how LDCs change as a consequence of a 1 °C increase in the average temperature of Australian state capital cities. These regional electricity demand data sets are then useful for economic modelling of electricity markets such as the NEM.     

土石坝洪水漫顶的事故树分析

通过土石坝现场调研与事故树分析相结合,对造成汛期土石坝洪水漫顶事故的因素进行识别和分析。以水库土石坝洪水漫顶作为顶上事件,对可能引发顶上事件的15个基本事件构建事故树,利用最小割集、最小径集及结构重要度,对其进行事故风险程度分析。结果显示,致使土石坝洪水漫顶的最小割集合有48个,表明土石坝洪水漫顶易发生;防止事故发生的最小径集合有3个;坝体存在隐患是控制土石坝洪水漫顶事故发生的关键。     

Improving the operation of a fuel-cell power unit with supervision control - A simulation study

Polymer electrolyte membrane fuel cells are proving to be a clean and efficient source of energy. Nowadays, extensive research efforts are being focused on bringing this technology to everyday use. An important aspect when integrating fuel cells in practical applications is their ability to respond to load demand. With respect to this, due to their complex internal dynamics, fuel cells belong to the group of more slowly responding sources. In order to make them more generally applicative they are often connected with a battery or a super-capacitor via a power converter to form a hybrid power source. A control algorithm, designed for such a system, represents an interesting challenge: it has to adapt to varying working conditions and operate optimally in terms of efficiency and reliability, while minimizing any impacts on the degradation of the components. Here, we present an approach using supervisory control automaton that switches between the system's operational modes and sets the references for the lower-level control loops. The evaluation of the efficiency and degradation is carried out in a simulation using a model of the widely used 1.2-kW Ballard Nexa power module.     

Uniqueness of Local Control Sets

The local controllability behavior near an equilibrium is discussed. If the Jacobian of the linearized system is hyperbolic, uniqueness of local control sets is established.     

基于粗糙集理论的除氧系统智能控制器设计

1前言热力除氧是一个较为复杂的过程,除氧系统由4台除氧器组成,每台除氧器都通过汽平衡和水平衡与其它除氧器相连。各除氧器之间的压力、水位相互影响,因而除氧系统控制难度较大,系统的鲁棒性差。系统运行中经常产生振荡,出现各除氧器水位此高彼低反复变化,同时压力也不稳定,除     

12V190燃气发电机组降排温试验研究

12V190燃气发电机组是目前燃气发电市场上的主力机型,随着市场的需要,对机组效率和可靠性的要求越来越高,因此降低排温,减少后燃和降低热负荷显得越来越重要。为此组织了12V190燃气发电机组降排温试验,通过采用切向进气管、预燃室火花塞、大流量水泵、不同的凸轮轴、全自动控制系统等开展了相关试验,从而摸索降低排温最佳配置。本文介绍了12V190燃气发电机组降排温试验的主要过程。     

超临界参数机组控制系统的特点及其控制策略

介绍了超临界参数火电机组的技术特点,分析了其控制系统中存在的问题,指出超临界直流锅炉机组是强耦合、多变量、非线性的控制对象,提出在系统设计中要充分考虑采用变参数、变设定值的控制方案代替根据偏差反馈控制的策略,适时的动态时间补偿以及静态平衡动态修正的控制方法。图1参2     

船用汽轮发电机组甩负荷工况控制系统研究

以某船用汽轮机发电机组为研究对象,对其控制原理进行理论分析与推导,建立其控制系统的数学模型,并在SIMULINK平台上完成了常规法甩负荷50％与100％仿真实验,得到两组响应曲线.分析结果表明:该控制系统能够实现机组的甩负荷工况转速控制,在负荷骤降的情况下可以保证机组安全稳定运行.     

论电站锅炉安装与制造厂相关的几个问题

就电站锅炉安装中在技术管理方面与制造厂相关的几个问题进行论述,并提出一些观点和建议,旨在提高锅炉安装技术管理水平;可供有关锅炉安装施工单位和制造厂参考。     

电站柴油机双机并联调速系统的仿真研究

建立了电站柴油机双机并联调速系统的模型 ,对柴油机的调速控制、负荷前馈控制、负荷均衡控制进行了 MATL AB仿真研究。结果表明 :采用负荷前馈控制可明显提高柴油机电子调速器的调速性能 ,引入负荷均衡控制后 ,可以在零稳态调速率条件下实现双机之间的负荷均匀分配