Computationally efficient multi-phase models for a proton exchange membrane fuel cell: Asymptotic reduction and thermal decoupling

Generally, multi-phase models for the proton exchange membrane fuel cell (PEMFC) that seek to capture the local transport phenomena are inherently non-linear with high computational overhead. We address the latter with a reduced multi-phase, multicomponent, and non-isothermal model that is inexpensive to compute without sacrificing geometrical resolution and the salient features of the PEMFC - this is accomplished by considering a PEMFC equipped with porous-type flow fields coupled with scaling arguments and leading-order asymptotics. The reduced model is verified with the calibrated and validated full model for three different experimental fuel cells: good agreement is found. Overall, memory requirements and computational time are reduced by around 2-3 orders of magnitude. In addition, thermal decoupling is explored in an attempt to further reduce computational cost. Finally, we discuss how other types of flow fields and transient conditions can be incorporated into the mathematical and numerical framework presented here.     

Almost disturbance decoupling and pole placement

We revisit here the Almost Disturbance Decoupling Problem (ADDP) (Willems, 1981) by state feedback with the objective to solve ADDP and simultaneously place the maximal number of poles in the closed-loop solution. Indeed, when ADDP is solvable, we show that, whatever be the choice of a particular feedback solution, the obtained closed-loop system always has a set of fixed poles. We characterize these Fixed Poles of ADDP. The other (non-fixed) poles can be placed freely, and we characterize the “optimal” solutions (in terms of ad hoc subspaces and feedbacks) which allow us to solve ADDP with maximal pole placement. From our contribution, which treats the most general case for studying ADDP with maximal, usually partial, pole placement, directly follow the solutions of ADDP with complete pole placement (when there are no ADDP Fixed Poles) and ADDP with internal stability (when all the Fixed Poles of ADDP are stable), without requiring the use of stabilizability subspaces, as in Willems (1981). We extend the concept of Self-Bounded Controlled-Invariant Subspaces (Basile & Marro, 1992) to almost ones. An example is proposed that illustrates our contributions.     

Advanced MHD mode active control at RFX-mod

A new control scheme, named Clean Mode Control (CMC) and based on the real-time correction of the aliasing of the sideband harmonics produced by the saddle coils, brought about a significant improvement of RFX-mod discharges, allowing the routine operation at 1.5 MA plasma current. A refinement of the electromagnetic model of the system is in progress by integrating new experimental measures and “virtual” measures provided by CARIDDI code. A Multi Input-Multi Output (MIMO) pseudo-decoupler control system was designed and the promising results of numerical simulations suggested starting its real-time implementation. A simplified MIMO decoupler in the mode space, based on a model retaining only the largest cross-coupled mode, is also being developed.     

总能系统与能源利用的统一性的性能评价指标体系

建立了以电量为基准的能源利用和总能系统的统一性性能评价指标体系，使各种用能方式的热力学性能可以在统一、客观、合理和科学的基准上进行比较和评价。研究了总能系统的设定，并在此基础上研究了热电联产机组的临界热电化，使热电联产总能系统节能与否的判断更容易。并对长期困扰热电联产发展，存在争议的供热战本和热价等问题进行了探讨。     

高精度电容器建模设计

针对电源分配网络设计不当使电源噪声过大的问题,提出了基于[CX2]S[CX]参数测量及矢量拟合的电容器Spice建模方法,并与传统的蒙特卡罗法建模进行比较,证明此电容器建模方法建模精度高,基于得到的电容器模型提出了最大违背点去耦选电容算法,解决了人工选择去耦电容器方案时反复设计的问题。     

隐式GPC算法在重介分选过程控制中的研究

为解决重介分选过程中重介质悬浮液密度与液位过程模型失配问题,引入隐式GPC算法对模型参数进行在线辨识,实现对重介质悬浮液的密度与液位解耦控制。仿真结果表明,针对重介分选过程模型具有大滞后、强耦合的这一特性,隐式GPC算法控制效果较好,抗干扰能力强,在模型失配的情况下,仍然保持系统的输出稳定。     

滚转导弹过载驾驶仪控制耦合解耦算法研究

舵机动力学滞后引起的控制耦合严重限制了过载驾驶仪在滚转导弹上的应用。建立滚转导弹驾驶仪模型,推导了等效舵机动力学传递函数矩阵,对比研究了基于最优舵面超前角度补偿和输出反馈动态的解耦控制方法,进行了仿真验证。仿真结果表明：随着转速与舵控系统频带比值的提高,控制耦合增加;基于最优舵面超前角度补偿的解耦方法实现简单,适用于工程应用,然而当转速与舵机频带的比值、输入指令频率与舵机频带的比值增加时,解耦效果变差,舵机控制效率降低;基于输出反馈动态解耦方法能够实现完全解耦,且受转速测量精度的影响较小,但该方法要求对舵机的传递函数精确已知,且补偿器的复杂性与舵机阶数密切相关,工程应用存在一定的难度。     

基于分量解耦融合的无线传感网时钟同步算法

无线传感器网络(WSN)时间同步精度的提高通常以增加额外同步能耗为代价,针对时间同步的高精度与低能耗的权衡问题,提出一种基于分量解耦融合的时钟同步算法。该算法结合双向广播同步机制和节点间时钟的相关性,利用分量解耦融合思想计算被同步节点与基准节点间的时钟偏差,同时根据线性无偏最小方差准则估计各个分量加权参数的取值。仿真结果表明,该算法能够在不增加额外同步能耗的条件下,相比PBS、TPSN和RBS算法,20轮同步后同步精度分别提高4.52μs、13.8μs以及25.48μs。     

电弧炉PID神经网络解耦控制器

结合电弧炉主电路系统,推导出电弧炉电气系统状态方程,在此基础上分析了电弧炉三相电流的耦合关系.使用PID神经元网络控制器对电弧炉电极系统进行解耦控制.给出了PID神经元网络控制器的权值初始化规则,其权值更新采用经典的BP算法.分别对于控制器的解耦性、抗干扰性和鲁棒性进行仿真,结果表明PID神经网络控制器具有很好的动态性...     

Power decoupling control of a solid oxide fuel cell and micro gas turbine hybrid power system

Solid Oxide Fuel Cell (SOFC) integrated into Micro Gas Turbine (MGT) is a multivariable nonlinear and strong coupling system. To enable the SOFC and MGT hybrid power system to follow the load profile accurately, this paper proposes a self-tuning PID decoupling controller based on a modified output-input feedback (OIF) Elman neural network model to track the MGT output power and SOFC output power. During the modeling, in order to avoid getting into a local minimum, an improved particle swarm optimization (PSO) algorithm is employed to optimize the weights of the OIF Elman neural network. Using the modified OIF Elman neural network identifier, the SOFC/MGT hybrid system is identified on-line, and the parameters of the PID controller are tuned automatically. Furthermore, the corresponding decoupling control law is achieved by the conventional PID control algorithm. The validity and accuracy of the decoupling controller are tested by simulations in MATLAB environment. The simulation results verify that the proposed control strategy can achieve favorable control performance with regard to various load disturbances.