火电单元机组协调控制系统的多变量IMC-PID设计

根据单元机组的低阶非线性模型，经过适当的简化，推导出一个双输入双输出、能够描述机组动态特性及机炉间相互耦合关系的传递函数矩阵。以该矩阵为基础，采用多变量内模控制的方法对单元机组协调控制系统进行设计。为了能方便地在实际工程中实现，文中推导出了该控制器的PID实现形式，最终简化的控制器结构简单，需调节参数少，可调参数与系统动态性能的对应关系明确。仿真试验表明：该控制器具有良好的解耦效果和负荷适应能力。图6参11     

基于遗传算法的机炉协调系统PID控制器优化

设计有效的机炉协调控制系统对提高热工自动化水平具有重要意义。针对火电机组的机炉控制系统，提出了一种基于遗传算法的多变量PID控制器参数优化方法。利用遗传算法提供的通用框架，在控制系统结构和控制器形式确定的情况下对控制参数进行全局优化。方法具有全局并行优化和面向目标函数的特点，与广义ZN整定方法相比的仿真研究表明，优化后的协调控制系统的动态性能有明显改善。并且客易扩展到其它控制方案下的参数优化，显示了方法的可行性和适用性。     

组态化预测控制及其在脱硫pH值控制中的仿真研究

为进一步提高火电机组脱硫系统的控制品质,用广义预测控制器替代传统脱硫pH值串级控制主调比例微分积分(PID)控制器,并通过算法简化与函数拟合提出了一种组态化预测控制方法,基于该算法通过集散控制系统(DCS)组态设计脱硫pH值控制系统。结果表明:组态化预测控制对pH值的控制在调节时间、超调量及动态偏差等方面均优于传统串级PID控制,可显著提高pH值的调节精度同时降低调节时间;与常规广义预测控制相比,组态化预测控制的控制性能基本相同。     

单元机组协调控制系统模糊自适应控制研究

单元机组协调控制系统的负荷控制对象存在耦合性和时变性,常规PID控制方案在负荷大范围变化时控制效果变差.为了提高协调控制系统的调节性能,采用了一种模糊自适应控制方案.基于300MW直流锅炉单元机组不同工况下采集的数据,建立了机组在210MW和270MW工况下的负荷控制对象动态数学模型,并进行了动态特性分析;基于常规PID协调控制方案,设计了一种模糊自适应PID控制器,可以自动调整控制器参数以适应工况的变化.锅炉控制器和汽轮机控制器均采用模糊自适应PID控制器.仿真结果表明,单元机组协调控制系统模糊自适应控制与常规PID控制相比,超调量降低,调节时间缩短,抗干扰能力和负荷适应能力增强.     

空冷机组协调控制系统鲁棒性分析

与传统水冷机组相比,空冷机组易受环境因素变化影响,对象特性更为复杂.建立空冷机组负荷-压力对象动态模型,分析其主要参数的变化规律及范围,在此基础上,采用机跟炉和炉跟机两种控制方式,仿真分析负荷-压力工作点、排汽压力、燃料发热量变化对控制系统性能的影响.结果表明:PID控制器具有较好鲁棒性,能够克服机组排汽压力、燃料发热量变化对控制系统的影响;负荷-压力工作点变化造成模型中制粉惯性和迟延、锅炉蓄热系数的变化以及对象自身非线性仍然是影响空冷机组控制品质的主要因素.     

基于遗传算法的协调控制系统鲁棒PID参数寻优

针对火电机组的机炉协调模型,提出一种基于遗传算法的协调控制系统多变量鲁棒PID参数寻优方法.该方法以控制器的设定点跟踪性能为寻优目标,鲁棒性能为约束惩罚条件,采用遗传算法对控制器参数进行寻优.仿真结果表明:与鲁棒H∞控制器降阶后所得到的PID控制器相比,利用本文方法得到的控制器具有更好的负荷设定值跟踪性能,并且具有良好的鲁棒性.     

基于对角递归神经网络整定的PID解耦单元机组负荷控制系统

针对火电厂单元机组具有多变量强耦合、非线性及参数时变的受控对象，提出了基于对角递归神经网络整定的PID解耦控制方法，其主要特点是能够提供一个对角递归神经网络来辩识系统模型，进而对PID控制器参数进行整定，实现多变量解耦控制。通过对火电机组负荷控制系统的设计和仿真研究，表明系统达到了动态近似解耦、静态完全解耦和无静差跟踪，并具有响应速度快，鲁棒性好等特点。图5参6     

超超临界直流炉机组负荷非线性预测控制及其仿真研究

超超临界直流炉机组协调控制系统存在非线性、强耦合等特性,常规PID控制器较难获取满意的控制效果。提出了一种非线性预测控制方法,将直流炉机理模型作为预测模型,利用二进制编码的免疫优化算法在线滚动优化得到最优控制序列,给出当前时刻最优的控制量并作用于对象。通过对超超临界机组负荷控制模型的试验仿真,表明该非线性优化预测控制方法的有效性,为超超临界协调控制系统的设计提供参考。     

基于GSA的水轮机调速系统非线性PID控制参数优化方法研究

水轮机调速系统是水电机组的核心控制系统,调速器控制参数优化与机组的安全稳定高效运行直接相关。针对现有研究的不足,建立了非线性调速系统模型,采用综合特性曲线描述水轮机模型,采用弹性水击模型描述压力引水系统特性;在此基础上,结合引力搜索算法(GSA)的优点,提出了基于GSA的非线性PID控制参数优化方法,并以我国某实际水电机组数据建立仿真模型,比较了不同优化方法和不同PID控制规律的组合控制效果。结果表明,基于GSA的水轮机调速系统非线性PID控制参数优化方法,能有效提高孤网运行条件下机组的动态品质。     

凝结水节流参与的1000MW火电机组快速变负荷调节

建立了具有一定精度的火电机组非线性模型,设计协调控制反馈控制器.同时针对1 000MW火电机组,分析凝结水节流过程的静态和动态特性,得到凝结水质量流量变化与机组负荷之间的传递函数,并设计合理的凝结水节流参与的协调控制通道控制器.在4种升负荷速率下对2种控制系统的动态特性进行验证,对积分绝对误差(IAE)、时间加权绝对误差的积分(ITAE)和自动发电控制(AGC)考核指标进行对比.结果表明:凝结水节流方案大大提高了机组升负荷速率,对新能源规模化并网大有裨益.     

基于灰色预测的汽温模糊免疫PID控制

火电厂汽温具有大惯性、大迟延和时变等特性,采用常规的PID串级控制方法难以取得满意的控制效果.借鉴生物免疫反馈响应过程的调节作用和模糊推理逻辑可逼近非线性函数的特性,结合灰色预测的优点,提出采用灰色预测的模糊免疫PID控制策略.火电厂汽温控制系统的仿真研究表明:该方法的控制品质良好,能适应对象参数的变化,具有较强的鲁棒性和自适应能力.     

Wide range operation of a power unit via feedforward fuzzy control[thermal power plants]

A two-level hierarchical control scheme for wide-range operation of fossil fuel power units is presented. At the supervisory level, a fuzzy reference governor generates, according to a variable pressure operating policy, the set-point trajectories to command the unit along any load demand pattern. At the control level, a feedforward-feedback control strategy is implemented. The feedforward control path contains a set of multi-input single-output fuzzy inference systems, designed from steady-state input-output plant data. The feedback control path consists of PID controllers in a multi-loop configuration, as currently available at power units. With this strategy, the feedforward path provides most of the control signal for wide-range operation, diminishing the control effort on the PID controllers. The feedback path supplies the complementary control signal component for regulation and disturbance rejection in small neighborhoods about the commanded trajectories. Simulation results demonstrate the feasibility of the control scheme to attain cyclic load-following operation     

Multivariable robust PID control for a PEMFC system

This paper proposes robust proportional-integral-derivative (PID) control for a proton exchange membrane fuel cell (PEMFC) system. We model a PEMFC as a multivariable system, and apply identification techniques to obtain the system’s transfer function matrices, where system variations and disturbances are regarded as uncertainties. Because robust control can cope with system uncertainties and disturbances, it has been successfully applied to improve the stability, performance, and efficiency of PEMFC systems in previous studies. However, the resulting robust controllers might be too complicated for hardware implementation. On the other hand, PID control has been widely applicable to engineering practices because of its simple structure, but it lacks stability analysis for systems with uncertainties. Therefore, by combining the merits of robust control and PID control, we design robust PID controllers for the PEMFC system. Based on evaluation of stability, performance, and efficiencies, the proposed robust PID controllers are shown to be effective.     

Design of the PID temperature controller for an alkaline electrolysis system with time delays

Electrolysis systems use proportional–integral–derivative (PID) temperature controllers to maintain stack temperatures around set points. However, because of heat transfer delays in electrolysis systems, the manual tuning of PID temperature controllers is time-consuming, and temperature oscillations often occur. This paper focuses on the design of the PID temperature controller for an alkaline electrolysis system to achieve fast and stable temperature control. A thermal dynamic model of an electrolysis system is established in the frequency domain for controller designs. Based on this model, the temperature stability is analysed by the root distribution, and the PID parameters are optimized considering the temperature overshoot and the settling time. The performance of the optimal PID controllers is experimentally verified. Furthermore, the simulation results show that the before-stack temperature should be used as the feedback variable for small lab-scale systems to suppress stack temperature fluctuations, and the after-stack temperature should be used for larger systems to improve the economy. This study helps ensure the temperature stability and control of electrolysis systems.     

大型火电机组可靠性分析技术的研究

提出了电站大型火电机组可靠性的计算公式和增长模型。介绍了单台机组和全厂多台机组可靠性的评价指标。可靠性增长模型的参数估计与拟合检验方法,给出了黄台发电厂大型火电机组可靠性的统计结果和可靠性增长的分析结果。表3参4     

Damping of a parallel AC-DC power system using PID power systemstabilizers and rectifier current regulators

A scheme for improving the dynamic stability of a parallel AC-DC power system is presented. It uses a proportional-integral-derivative (PID) power-system stabilizer and a PID rectifier current regulator to enhance the damping for the electromechanical mode of the system. The parameters of the proposed PID controllers are determined using a unified approach based on modal control theory. Eigenvalue analyses are performed for the system under various operating conditions in order to compare the damping effects provided by the two different control schemes. The effectiveness of the proposed damping schemes under disturbance conditions is demonstrated by computer-simulated dynamic-response tests based on a nonlinear system model     

超临界机组协调系统的模糊增益调度预测控制

针对火电厂超临界机组多变量锅炉-汽机协调系统在大工况范围内运行具有强非线性的特点,提出了一种基于模糊增益调度的预测控制方法.通过现场试验获取多个工况点处的协调系统传递函数模型,结合增益调度和模糊逻辑推理方法建立全局自适应模糊模型,利用预测控制技术确保控制系统全局优化品质.基于模糊增益调度的预测控制方法设计火电厂超临界机...     

基于非线性模型的励磁控制系统仿真研究

本文针对同步发电机的励磁控制系统,基于经典的PID方案和现代的状态反馈(SFB)方案,设计了几种新型的励磁控制方案,同时,比较了这些方案与常规的PID、PID加PSS和SFB方案对励磁控制系统的影响,所用模型为非线性。仿真结果表明,本文所提出的几种控制方案对于提高电力系统运行的品质指标、抑制系统的振荡、增加系统的鲁棒性等是有益的,并且利于用微机实现。     

Multivariable control strategy for variable speed, variable pitch wind turbines

Reliable and powerful control strategies are needed for wind energy conversion systems to achieve maximum performance. A new control strategy for a variable speed, variable pitch wind turbine is proposed in this paper for the above-rated power operating condition. This multivariable control strategy is realized by combining a nonlinear dynamic state feedback torque control strategy with a linear control strategy for blade pitch angle. A comparison with existing strategies, PID and LQG controllers, is performed. The proposed approach results in better power regulation. The new control strategy has been validated using an aeroelastic wind turbine simulator developed by NREL for a high turbulence wind condition.