PEMFC发电系统的自适应模糊控制与动态分析

监测和控制燃料电池的过程中,需要获得各种实时数据.质子交换膜燃料电池(PEMFC)发电系统中的参数强耦合、高度非线性特性增加了对其控制的难度,传统的PI控制虽然对模型精确的系统有较好的控制效果,但对于参数波动的系统则无法获得较高的控制性能.针对以上情况,基于PEMFC发电系统的动态仿真模型,根据重整器在燃料电池发电系统中的作用,设计了自适应模糊控制器.利用模糊控制规则在线控制氢气摩尔流,从而控制PEMFC发电系统的输出功率.仿真结果表明,该动态模型能够预测输出电压.响应曲线显示出自适应模糊控制算法能够较好控制燃料电池有功和无功功率的输出.模型具有良好的负载跟踪特性.     

磁记录浮动块动态参数仿真

建立了考虑浮动系统动态特性综合分析的近似模型;在磁记录浮动块动态性能方面,给出了浮动系统动力参数(刚度、阻尼、固有频率)及其变化特性的仿真测试方法与结果。     

基于LPV模型的风能转换系统增益调度控制

在额定风速以下,风能转换系统需要通过控制发电机转速使风能的捕获率最大.根据风速的多时间尺度特性,建立风能转换系统的非线性机理模型,进一步得到其归一化误差的线性参数变化(LPV)系统模型;为获取最大风能捕获和减少机械振荡,在PI控制策略的基础上,利用基于LPV模型的增益调度控制器进行动态补偿.仿真结果表明:补偿后系统的功率系数和叶尖速比追踪其最优值的精度更高,鲁棒性更好,体现了更好的动态性能.     

顺流型熔融碳酸盐燃料电池单体性能研究

研究高效发电方法问题,燃料电池内部的温度、电流密度和反应气体浓度等参数分布对燃料电池的安全高效运行具有重要影响.全面考虑了熔融碳酸盐燃料电池内部电特性和热特性,为提高预测电池性能的准确性,提出了一整套熔融碳酸盐燃料电池单体二维数学模型,并在VC++环境下利用模型对顺流形式的熔融碳酸盐燃料电池单体的主要性能参数进行了稳态数值仿真.得出了燃料电池内部的温度、电流密度和反应气体浓度等参数的变化趋势,证明了建立的仿真模型能够有效的反映燃料电池内部的温度场、电流密度场和反应气体组分场稳态的特性,结果表明对熔融碳酸盐燃料电池的设计及运行具有一定的参考价值.     

动态优化双估计器的多模型自适应混合控制

针对参数子集个数较多导致计算量较大和由于系统参数发生跳变造成系统暂态性能差的问题,本文提出了基于动态优化双估计器的多模型自适应混合控制方法.首先对多个参数子集进行动态优化得到最优参数子集,减少了需要计算的模型数量,提高了系统收敛速度;其次对被控对象设置一个固定初值的估计器和一个可重新赋值的估计器,固定估计器用于初始时刻对参数的估计,可赋值估计器动态调整估计初值用于减小估计误差,提高系统暂态性能.最后的仿真结果表明了该方法的有效性,并给出了系统的稳定性及收敛性分析.     

大时滞不确定系统的滞后时间削弱与自抗扰控制

针对具有变时滞、变参数和扰动的大时滞不确定系统的控制问题,本文提出了滞后时间削弱与自抗扰控制方法,综合应用了前馈控制、反馈控制和自抗扰补偿控制.为了提高系统的稳定性,在前馈控制器的设计中采用了系统的边界模型确定控制器参数取值范围;采用系统边界模型输出与系统实际输出的动态加权和作为反馈控制器的输入.为了提高系统控制的性能,自抗扰补偿控制回路的设计基于标称模型的补偿控制器.理论证明和仿真结果表明,所提出的方法是有效的,其在具有模型参数变化、滞后时间变化和外部扰动情况下,能保证系统的稳定性和良好的控制性能.     

鲁棒PDF控制策略在永磁同步电机系统中的设计及仿真

对电机控制系统的经典反馈设计方案是建立在简化的受控对象模型基础之上,而实际模型参数的变化会引起控制系统性能的改变;文章针对实际应用的永磁同步电机,为了保证电机控制系统的强鲁棒性,通过对其系统灵敏度的理论推导,给出了一种新的控制器参数设计方法;该设计方法以系统灵敏度为评价指标来度量系统的鲁棒性,结合应用于二阶控制对象的伪微分反馈控制器结构,来削弱控制对象参数值的改变对控制系统性能的影响;并建立了精确的永磁同步电机仿真模型,将该方法应用于其速度控制;仿真结果表明在该控制方案下,在永磁同步电机的转动惯量和定子电阻值变化时具有较小超调量变化(小于4％)的响应特性;同时与普通PID控制对比分析,验证了用该方案设计的PMSM调速系统具有较高的抗参数变化的鲁棒性.     

基于支持向量机的PEMFC电特性仿真研究

质子交换膜燃料电池(PEMFC)是一个非线性、多输入、强耦合、大时延的复杂动态系统,传统的根据系统物理和化学的特性建立的数学模型,具有较大的局限性.从质子交换膜燃料电池的物理结构、输出特性曲线和数学模型方面对其进行了描述,针对PEMFC的复杂动态环境,利用支持向量机对于给定试验样本数据的良好的泛化性能,根据在自制的PEMFC单电池上进行试验所得到的数据,对质子交换膜燃料电池的电特性进行了回归运算.结果发现,在样本数目较小时,采用指数型径向基核函数对PEMFC进行回归运算较为理想;当数据样本数目巨大时,高斯径向基核函数可以获得很好的支持向量稀疏度,具有明显的优越性,这为PEMFC燃料电池的建模仿真及有效控制其电压输出特性提供了新的思路.     

质子交换膜燃料电池建模与动态仿真

对质子交换膜燃料电池（PEMFC）电堆进行电输出特性研究,有助于改善燃料电池的设计,提高其性能。运用MATLAB的Simulink仿真工具对PEMFC建立仿真模型,通过所建立的电堆参数模型,就能够研究主要运行参变量对电堆动态输出性能和电堆非线性内阻产生的影响。当电堆输出电流出现阶跃变化时,对电堆电压,输出功率,消耗功率,电堆效率,非线性内阻的动态响应,进行了仿真和结果分析。仿真结果符合文献[7]实验数据,表明此参数模型是可操作和有效的,并可方便地用于PEMFC控制方法研究。     

IMM算法实现非线性状态估计的研究与仿真

研究交互式多模型算法的非线性状态估计性能,按照工作点把非线性系统线性化为多个子模型,建立多模型自适应状态估计器.利用Monte-Carlo仿真法将其与EKF和UKF算法在不同参数下的噪声抑止能力和鲁棒性进行了比较,并分析了马尔可夫参数和模型个数对算法性能的影响.仿真结果表明该算法能达到理想的估计精度、收敛速度、稳定性和鲁棒性,能克服单一估计器由于参数变化和外部扰动所造成的估计误差过大,甚至发散的问题,能覆盖大范围的参数不确定性.     

A reactive scheduling and control framework for integration of renewable energy sources with a reformer-based fuel cell system and an energy storage device

The main technological barrier in relying solely on renewable energy resources is that the sources such as wind and solar are highly intermittent in availability and result in uncertainty in demand satisfaction. This paper focuses on the integration of these uncertain renewable energy sources along with relatively deterministic energy sources such as reformer based fuel cell and battery. The power mix scenario between these multiple renewable energy sources along with the reformer based fuel cell system, coupled with an energy storage option is envisaged in this paper to ensure undisrupted power supply, to combat the possible intermittent nature of these renewable sources. An appropriate scheduling layer which provides a detailed plan of the optimum contribution of the various available power sources is considered over one week (7 days) duration. A model predictive control (MPC) scheme is deployed at the lower level control layer that receives a measurement of the possible fluctuations or uncertainties in the renewable power sources and maintains a smooth operation of the power generation system through appropriate decisions on generation via the reformer based fuel cell or by exploiting the battery storage, to ensure a delay-free delivery of power to the external load. During real-time operation of the plant, due to the uncertainties in the contribution from solar and wind sources, the power demanded from the fuel cell and the battery is varied accordingly by the MPC layer to meet the overall power demand. The performance of the designed MPC to maintain a smooth delivery of power in both the absence and presence of uncertainties in the renewable energy sources, with and without a reactive feedback between the scheduling and control layers, is illustrated using case studies.     

Development Of Cvt Control System And Its Use For Fuel‐Efficient Operation Of Engine

Continuously variable transmission (CVT) provides an automobile with the ability to change the gear ratio continuously, which can then improve not only ride quality such as acceleration performance but also fuel‐efficiency. However, to take advantage of the ability, a control system that can precisely control the gear ratio is required. This paper proposes such a control system for a belt‐driven CVT system. For controller design, first the CVT system is modeled by analytical and experimental approaches. The resultant static and dynamic characteristics provide a nonlinear first‐order model with an uncertain time constant and time delay. The nonlinear steady‐state gain is adjusted to one by a gain‐scheduled pre‐compensator. Thereby the plant model becomes a linear first‐order lag system with a dead time. The next step is controller design using the plant model. To guarantee stability and control performance against the parameter variation and time delay, the μ‐synthesis, a robust control method, is employed for feedback control. In addition, a feedforward controller is incorporated into the feedback control system to obtain better output response. The feedforward controller is given by a combination of the inverse system of the plant and a reference model that gives desired output response. As a result, the control system becomes a two‐degree‐of‐freedom control system. To evaluate the performance of the control system and its effectiveness on the fuel‐efficiency, computer simulation and driving tests were conducted. The simulation and experiment results prove that the proposed control system can make the gear ratio track a reference output quickly and precisely in the presence of the uncertainties. The results also show that the control system improves fuel‐efficiency by changing the gear ratio so that the engine torque and its revolution speed can satisfy optimum‐efficiency operating condition.     

Operation mode control of a hybrid power system based on fuel cell/battery/ultracapacitor for an electric tramway

This paper focuses on describing a control strategy for a real tramway, in Zaragoza (Spain), whose current propulsion system is to be replaced by a hybrid system based on fuel cell (FC) as primary energy source and batteries and ultracapacitors (UCs) as secondary energy sources. Due to its slow dynamic response, the FC needs other energy sources support during the starts and accelerations, which are used as energy storage devices in order to harness the regenerative energy generated during brakings and decelerations. The proposed energy management system is based on an operation mode control, which generates the FC reference power, and cascade controls, which define the battery and UC reference powers in order to achieve a proper control of the DC bus voltage and states of charge (SOC) of battery and UC. The simulations, performed by using the real drive cycle of the tramway, show that the proposed hybrid system and energy management system are suitable for its application in this tramway.     

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.      

质子交换膜燃料电池动态建模及其双模控制

由于已提出的质子交换膜燃料电池(PEMFC)模型难于控制, 提出利用MATLAB/SIMULINK仿真工具进行PEMFC系统动态建模, 同时为实现对PEMFC系统输出电压的控制, 采用了基于模糊规则切换的模糊逻辑控制器(FLC)和比例积分微分控制器(PID)相结合的双模控制方式. 仿真结果证明该动态模型易于控制, 能够反映出PEMFC系统的动态输出特性, 而且验证了基于模糊规则切换的双模控制能够有效抑制扰动, 改善PEMFC系统的动态输出特性, 保证系统的稳定运行, 有助于对PEMFC系统的输出性能分析以及实时控制系统的设计.     

MPC for battery/fuel cell hybrid vehicles including fuel cell dynamics and battery performance improvement

In this paper, the performance and durability of hybrid PEM fuel cell vehicles are investigated. To that end, a hybrid predictive controller is proposed to improve battery performance and to avoid fuel cell and battery degradation. Such controller deals with this complex control problem by handling binary and continuous variables, piecewise affine models and constraints. Moreover, the control strategy is to track motor power demand and keep batteries close to a desired battery state of charge which is appropriately chosen to minimize hydrogen consumption. It is important to highlight the consideration of constraints which are directly related to the goals of this paper, such as minimum fuel cell power threshold and time limitation between fuel cell startups and shutdowns. Furthermore, different models have been elaborated and particularized for a vehicle prototype. These models include few innovations such as a reference governor which smooths fuel cell power demand during sharp power profiles, forcing batteries to supply such peaks and resulting a longer fuel cell lifetime. Battery thermal dynamics are also taken into account in these models in order to analyze the effect of battery temperature on its degradation. Finally, this paper studies the feasibility of the real implementation, presenting an explicit formulation as a solution to reduce execution time. This explicit controller exhibits the same performance as the hybrid predictive controller does with a reduced computational effort. All the results have been validated in several simulations.     

充液航天器姿态的自适应非线性动态逆控制

讨论了充液航天器大角度姿态机动自适应非线性动态逆控制设计.推导了航天器-液体晃动耦合系统动力学方程.采用单摆等效力学模型对液体燃料晃动进行动力学建模.由于充液航天器控制系统的强耦合非线性,故采用神经网络构造系统的自适应非线性动态逆控制器.通过实际算例对该控制器的跟综性能进行了测试,结果证明该自适应非线性动态逆控制器在包...     

基于启发式动态规划的固体氧化物燃料电池优化控制研究

固体氧化物燃料电池(SOFC)系统是一个非线性系统,现存的建模方法和优化控制算法很难对其进行精确的建模及优化控制;针对此问题,采用基于数据的建模方法,对固体氧化物燃料电池系统进行BP神经网络建模,然后在此基础上,首次采用启发式动态规划(HDP)算法对固体氧化物燃料电池系统中的各种气体分压、输出电压以及温度进行优化控制;Matlab仿真结果表明,基于BP神经网络的HDP优化算法具有收敛速度快、鲁棒性强、控制精度高等优点,并使固体氧化物燃料电池系统在负载变化时很快稳定输出电压,实现了优化控制,减少能耗。