Modeling and control of a PEM fuel cell system: A practical study based on experimental defined component behavior

In this contribution, the dynamical behavior of a polymer electrolyte membrane (PEM) fuel cell system is modeled; related control approaches are developed. The system model used for experimental and modeling purposes describes a 1.2 kW PEM fuel cell stack and an air blower. Due to the dynamical fuel cell–blower interaction the fuel cell stack and the blower model are validated to real systems respectively. Additionally, a feedback based on PI-control is used for hydrogen pressure control with an anode inlet valve. This controller is able to eliminate a stationary error between the anode and cathode pressures. For principal investigations three control approaches, a classical static feed-forward control approach, a state-space feedback control, and a novel gain-scheduling approach are developed, applied, and compared. As result, it can be shown that the feed-forward approach lacks in performance recovering the excess oxygen ratio to the desired level. The state-space feedback control shows stationary error. The introduced gain-scheduling control approach leads to a fast excess oxygen ratio recovery without stationary deviations.     

Passivity based control of a distributed PEM fuel cell model

This work considers the controlled load change of proton exchange membrane (PEM) fuel cells. Due to the intrinsic nonlinearities of fuel cells, load changes are quite challenging. In the case of a low temperature PEM fuel cell, there is the possibility of undesired liquid water formation. Most available control concepts are heuristic linear controller structures based on a perfectly mixed fuel cell model. In this work a nonlinear controller for one-dimensional spatially distributed model of a PEM fuel cell is presented. The fuel cell model is derived from first principles. The concept of passivity is used to design the controller. A suitable control Lyapunov function is chosen and passivity of the fuel cell is shown. A state-feedback law is derived that can guarantee stability of the closed-loop system over a wide range of operation conditions. In order to make the feedback law applicable to fuel cells with limited measurement information an observer is designed. In a final step the state-feedback law and the observer are combined to an output-feedback controller.     

Robust Nonlinear Observer And Observer‐Backstepping Control Design For Surface Ships

A robust passive non‐linear observer, utilizing the sliding mode concept and acceleration feedback (AFB) technique, is developed for ships. The main advantage of the proposed observer is that it is robust and that it takes the Coriolis‐centripetal matrix (C‐matrix) into account. The observer reconstructs velocities of ships and bias from slowly varying environmental disturbances. It also filters out the noise and wave frequency data from measurements to protect the actuators from wear and excessive fuel consumption. The sliding mode technique is introduced to improve robust performance against neglected disturbances, uncertainties, and unmodeled dynamics. The acceleration feedback technique and coordinate transformation are used for reshaping the inertia matrix and removing the C‐matrix from the mathematical model. Then, the observer design and stability analysis become simpler. An output feedback controller using observer backstepping and the Lyapunov redesign technique is derived, and the global stability of the observer and observer‐controller system is shown by Lyapunov stability theory. A set of simulations was carried out to verify the performance of the proposed observer and controller.     

Time‐varying input delay compensation for nonlinear systems with additive disturbance: An output feedback approach

This paper addresses the output feedback tracking control of a class of multiple‐input and multiple‐output nonlinear systems subject to time‐varying input delay and additive bounded disturbances. Based on the backstepping design approach, an output feedback robust controller is proposed by integrating an extended state observer and a novel robust controller, which uses a desired trajectory‐based feedforward term to achieve an improved model compensation and a robust delay compensation feedback term based on the finite integral of the past control values to compensate for the time‐varying input delay. The extended state observer can simultaneously estimate the unmeasurable system states and the additive disturbances only with the output measurement and delayed control input. The proposed controller theoretically guarantees prescribed transient performance and steady‐state tracking accuracy in spite of the presence of time‐varying input delay and additive bounded disturbances based on Lyapunov stability analysis by using a Lyapunov‐Krasovskii functional. A specific study on a 2‐link robot manipulator is performed; based on the system model and the proposed design procedure, a suitable controller is developed, and comparative simulation results are obtained to demonstrate the effectiveness of the developed control scheme.     

Active disturbance rejection control for voltage stabilization in open-cathode fuel cells through temperature regulation

Temperature regulation is an important control challenge in open-cathode fuel cell systems. In this paper, a feedback controller, combined with a novel output-injection observer, is designed and implemented for fuel cell stack temperature control. The first functionality of the observer is to smooth the noisy temperature measurements. To this end, the observer gain is calculated based on Kalman filter theory which, in turn, results in a robust temperature estimation despite temperature model uncertainties and measurement noise. Furthermore, the observer is capable of estimating the output voltage model uncertainties. It is shown that temperature control not only ensures the fuel cell temperature reference is properly tracked, but, along with the uncertainty estimator, can also be used to stabilize the output voltage. Voltage regulation is of great importance for open-cathode fuel cells, which typically suffer from gradual voltage decay over time due to their dead-end anode operation. Moreover, voltage control ensures predictable and fixed fuel cell output voltages for given current values, even in the presence of disturbances. The observer stability is proved using Lyapunov theory, and the observer's effectiveness in combination with the controller is validated experimentally. The results show promising controller performances in regulating fuel cell temperature and voltage in the presence of model uncertainties and disturbances.     

燃料电池分散发电系统阳极部分的建模和控制

燃料电池分散发电系统要求安全性、可靠性和持久性,系统控制十分重要,而用户的实时功率需求以及多设备多仪表多性能参数的特点使整个系统的实时控制变得复杂。该文主要介绍发电系统阳极部分的结构设计和控制实现方法。系统参数关系的强非线性要求控制必须以动态仿真模型为基础。在实时数据的基础上进行物质量上的反馈计算,能够使进入电堆阳极的氢气在系统运行过程中始终维持在理想的湿度水平。将二次型性能指标引入单神经元自适应PID控制,通过调节二级减压阀的气体流量。可以很好地维持电堆膜阳极侧压力始终与阴极侧压力保持理想的压力差水平。经仿真验证系统运行性能良好。     

缸内直喷汽油机的自抗扰轨压跟踪控制器设计

获得期望的共轨压力是保证缸内直喷发动机(GDI)稳定工作和喷油量精确控制的一个重要前提. 本文针对缸内直喷汽油发动机轨压控制问题, 首先通过动力学分析建立了共轨燃油喷射系统的数学模型; 由于系统中存在有较强的非线性和不确定性, 采用基于模型但对模型的精确形式依赖较小的自抗扰控制技术设计轨压跟踪控制器,其中线性扩张状态观测器(ESO) 对系统存在的总扰动和不确定性进行了估计, 非线性误差反馈控制(NLSEF) 则采用反馈补偿实现扰动的抑制. 最后, 通过给定不同的参考轨压对控制器的有效性进行验证, 仿真结果表明控制性能是满意的.     

Output feedback second‐order sliding mode control of the cart on a beam system

We propose an output feedback second‐order sliding mode controller to stabilize the cart on a beam system. A second‐order sliding mode controller is designed using a Lyapunov function‐based switching surface and finite‐time controllers, while the state estimator is designed based on the Luenberger‐like observer. The proposed observer extends the applicability of Luenberger‐like observer to nonlinear systems that are not input–output linearizable, but can be approximately input–output linearized. The approximation is based on the physical property of the system, wherein certain terms in the total energy are neglected. Extensive numerical simulations validate the robustness of the proposed controller to parametric uncertainties using estimated states. Copyright © 2009 John Wiley & Sons, Ltd.     

State feedback tracking control for indirect field-oriented induction motor using fuzzy approach

This paper deals with the synthesis of fuzzy controller applied to the induction motor with a guaranteed model reference tracking performance. First, the Takagi-Sugeno (T-S) fuzzy model is used to approximate the nonlinear system in the synchronous d-q frame rotating with field-oriented control strategy. Then, a fuzzy state feedback controller is designed to reduce the tracking error by minimizing the disturbance level. The proposed controller is based on a T-S reference model in which the desired trajectory has been specified. The inaccessible rotor flux is estimated by a T-S fuzzy observer. The developed approach for the controller design is based on the synthesis of an augmented fuzzy model which regroups the model of induction machine, fuzzy observer, and reference model. The gains of the observer and controller are obtained by solving a set of linear matrix inequalities (LMIs). Finally, simulation and experimental results are given to show the performance of the observer-based tracking controller.     

基于二维混合模型和状态观测器的重复控制设计

针对一类正则线性系统, 提出一种基于状态观测器和二维混合模型的重复控制系统设计方法. 首先, 通过构造一个状态观测器来重构系统的状态, 建立基于重构状态的线性控制律. 然后, 通过独立地考虑重复控制系统的连续控制过程与离散学习行为, 给出基于状态观测器和重构状态反馈的连续/离散二维混合模型. 针对这个混合模型, 运用二维Lyapunov泛函方法, 以线性矩阵不等式(Linear matrix inequality, LMI)的形式给出重复控制系统存在重复控制器和状态观测器的充分条件, 所给条件可用Matlab工具箱方便地求解. 数值仿真验证了本文所提方法的有效性.     

基于观测器的一类连续非线性系统的采样控制

首先使用反演方法分别设计了系统的连续时间状态反馈控制器、连续时间观测器和基于连续时间观测器的连续时间控制器. 接下来, 利用零阶保持法对连续时间状态反馈控制器进行离散化, 获得了状态反馈采样控制器; 利用零阶保持法对基于连续时间观测器 的连续时间控制器离散化, 获得了基于连续时间观测器的采样控制器; 利用Euler法对连续时间观测器离散化, 同时利用零阶保持法对控制器离散化, 从而获得了采样观测器和基于采样观测器的采样控制器. 本文论证了上述状态反馈采样控制器和基于连续时间观测器的采样控制器可以保证闭环系统渐近稳定, 而基于采样观测器的采样控制器可以保证被控对象的状态是有界的, 其最终边界依赖于设计参数与采样周期. 最后, 通过选择适当的采样周期, 完成了闭环采样控制系统的设计. 一个船舶航向控制的例子表明应用本文 所提方法设计出的三种采样控制器具有良好的控制效果.     

Observer‐based compensation control of servo systems with backlash

For compensating backlash phenomenon in servo systems, the authors propose an observer method in this paper to estimate both system states and vibration torque before controller design. First, a systematic scheme is given to obtain plant parameters, which is very important in observing system states. This is a parameter estimation principle that gives a crude estimation and computes the differences between the crude and true values. As a result, the precise value of the parameters is obtained by adding together the crude value and the difference. Then, based on the precise estimated parameters, an extended state observer (ESO) is designed to obtain feedback and feedforward signals. Consequently, robust compensation control is achieved by designing an output feedback controller, consisting of a feedback term and a feedforward term. Finally, in order to validate the proposed approach, extensive experiments are performed on a practical servo system with backlash nonlinearity.     

Nonlinear Observer-based Control Design and Experimental Validation for Gasoline Engines with Exhaust Gas Recirculation

This paper presents a nonlinear observer-based control design approach for gasoline engines equipped with exhaust gas recirculation (EGR) system. A mean value engine model is designed for control which includes both the intake manifold and exhaust manifold dynamic focused on gas mass flows. Then, the nonlinear feedback controller based on the developed model is designed for the state tracking control, and the stability of the close loop system is guaranteed by a constructed Lyapunov function. Since the exhaust manifold pressure is usually unmeasurable in the production engines, a nonlinear observer-based feedback controller is proposed by using standard sensors equipped on the engine, and the asymptotic stability of the both observer dynamic system and control dynamic system are guaranteed with Lyapunov design assisted by the detail analysis of the model. The experimental validations show that the observer-based nonlinear feedback controller is able to regulate the intake pressure and exhaust pressure state to the desired values during both the steady-state and transient conditions quickly by only using the standard sensors.     

Output Tracking Control of a Hydrogen-air PEM Fuel Cell

Hydrogen-air proton exchange membrane (PEM) fuel cell is a promising clean energy. However, the stack output tracking control is still a challenging problem due to the soft characteristic of the stack. Both over-and less-control will cause the stack flooding or oxygen lacking which dramatically decreases the life of stacks. Traditional control methods rely on the accurate model of the fuel cell system, which is a high-order nonlinear system, and involve a complex controller design process. This paper combines the data-based fuzzy cluster modeling technology with the sliding mode control and the integral actions. The sliding mode controller tracks the dynamic changes of the fuel cell system and the integral controller eliminates the steady-state errors. Simulation results demonstrate good performance of the proposed control method.      

基于模糊逻辑与遗传算法的燃料电池热管理方法研究

有效的质子交换膜燃料电池(Proton Exchange Membrane Fuel Cell,PEMFC)热管理是提升氢燃料电池汽车安全性、耐久性以及运行效率的关键因素之一.该文提出一种PEMFC电堆热管理控制方法,使电堆出入口温度保持在设定值.该方法以PEMFC热管理系统模型中电堆出入口温度的变化为依据,设计一种二...     

基于LESO的MMC-RPC反馈线性化直接功率控制

模块化多电平铁路功率调节器作为一个耦合的多变量非线性系统, 传统PI控制的直接功率控制难以实现 对系统的精确解耦. 本文提出了一种基于线性扩张状态观测器的反馈线性化直接功率控制方法, 根据Lie导数构建 了模块化多电平铁路功率调节器(MMC-RPC)两输入/两输出功率仿射模型, 设计了精确反馈线性化功率解耦控制 器. 针对不确定因素等扰动对精确反馈线性化控制效果的影响, 设计了线性扩张状态观测器对扰动进行观测和补 偿, 实现了功率的精确跟踪控制. 最后, 通过MATLAB/Simulink平台搭建仿真模型对所提控制方法进行了验证.     

混合悬浮系统恒定气隙控制策略研究

本文对混合悬浮系统精确的数学模型进行了分析,分别对传统的PID直接反馈控制器和带状态观测器的状态反馈控制器进行了设计和比较,仿真结果表明,这两种控制器都能够使悬浮系统达到稳定,但是后者可以解决气隙速度信号估算的难题.     

一类非线性对象基于区间观测器的L2增益性能综合

本文针对一类非线性系统,首次考虑了基于区间观测器的L2增益性能控制器设计问题.该控制器的设计主要分两个步骤:首先,设计了该非线性系统的区间观测器,使得观测器系统与原系统之间的误差系统为单调系统;然后,基于该区间观测器系统设计了观测器状态反馈控制律,使得相应的闭环系统为渐近稳定且具有L2增益性能.最后,仿真数例表明了本文所提出方法的有效性.     

Observer‐Based Adaptive Output Feedback Fault Tolerant Control for Nonlinear Hydro‐Turbine Governing System with State Delay

This paper focuses on the problem of adaptive output feedback fault tolerant control for a nonlinear hydro‐turbine governing system. A dynamic mathematical model of the system is established, which aims to investigate the dynamic performance of the model under servomotor delay and actuator faults. Then, a fault estimation adaptive observer is proposed to achieve online real‐time diagnosis of system faults. Based on the online fault estimation information, an observer‐based adaptive output feedback fault tolerant controller is designed. Furthermore, under reasonable assumptions, the results demonstrate that the closed‐loop control system can achieve global asymptotic stability by Lyapunov function. Finally, the numerical simulation results are presented to indicate the satisfaction control effectiveness of the proposed scheme.     

Robust Backstepping Sliding Mode Controller Investigation for a Port Plate Position Servo System Based on an Extended States Observer

For reducing throttling loss in a pilot oil pipe in a hydraulic system based on common pressure rail, this paper proposes a solution that increases efficiency by reducing the relieving pressure. In order to compensate for the resulting control performance degradation, the paper takes a valve controlled swing motor system under low pressure as the research aim. Considering the uncertainty of external disturbance and flow parameters, the mathematical model of the system is established, using an extended state observer to estimate the external disturbances in real time to increase the compensation value and state feedback for the robust backstepping sliding mode controller. Finally, the simulation results confirm the control algorithm proposed is effective for keeping control performance in decreasing pressure conditions.