广义预测控制在堆芯变功率控制中的应用

针对不同功率水平下稳态中子密度造成的堆芯功率模型非线性问题,将广义预测控制(GPC)应用于堆芯功率控制,实现变工况条件下堆芯功率的自动控制。本文首先基于零功率堆芯模型和温度反馈模型建立堆芯功率模型,基于该模型阶次设计预测时域,并根据系统输入输出数据在GPC校正环节通过带遗忘因子的最小二乘法在线辨识不同功率水平下的模型参数。为验证控制器的鲁棒性,在满功率平稳运行时加入反应性扰动。基于MATLAB平台对控制器的性能进行仿真验证。结果表明,本文所设计的GPC在堆芯变工况运行时能使输出功率快速、准确地跟踪设定值,并能在线辨识不同功率水平的堆芯模型参数,具备一定的抗干扰能力。     

液态熔盐堆堆芯功率模糊PID控制

液态熔盐堆采用熔融氟化盐为燃料,燃料熔盐出口温度是衡量熔盐堆安全的重要指标。通过堆芯功率控制可实现燃料熔盐出口温度控制。将液态熔盐堆堆芯划分成内区和外区,并基于能量守恒原理建立堆芯非线性模型,采用微扰理论对非线性模型进行线性化。基于堆芯线性化模型,采用模糊比例-积分-微分(PID)控制器设计堆芯功率控制系统。以熔盐增殖堆(MSBR)为例,开展堆芯功率控制仿真。结果表明,引入10^-3、2×10^-3阶跃反应性时,模糊PID控制器可以减小系统响应的上冲幅度和超调量,并且在堆芯功率发生了较大的负荷变化时,模糊PID控制器可以对堆芯功率的变化实现良好跟踪。故所采用的模糊PID控制器具有良好的动态性能,可实现对堆芯功率的良好控制。     

模型预测控制在压水堆堆芯功率控制中的应用

在压水堆核电站中,堆芯功率的自动控制难以实现。将模型预测控制方法应用于压水堆堆芯,以实现堆芯功率的自动控制。堆芯功率自动控制模型的建立是以反应堆堆芯模型和模型预测模型为基础的。反应堆堆芯模型包括中子动力学模型、热工水力学模型和反应性模型,模型预测模型以状态空间形式表述。为评估所设计的基于状态空间的模型预测控制系统的性能,设计了堆芯功率控制仿真实验。模拟结果表明:所设计的控制方法能快速、准确地控制堆芯功率,跟踪负荷变化。     

基于外中子源强度的ADS次临界堆堆芯功率控制

加速器驱动次临界系统(Accelerator Driven subcritical System,ADS)可用于发电、增殖和嬗变等多种用途。在瞬态变工况时,需要实现功率的准确调节,以保证反应堆瞬态的安全性。我国自主设计的加速器驱动嬗变研究装置CIADS(China Initiative Accelerator Driven System)次临界反应堆仅依靠加速器外中子源强度实现对堆芯功率调节。为研究基于外中子源强度的CIADS堆芯控制响应特性,采用集总参数法建立堆芯非线性模型,利用微小扰动线性化方法对堆芯非线性模型进行线性化处理,建立双输入双输出的堆芯状态空间模型。基于该模型设计堆芯功率模糊PID(Proportional Integral Derivative)控制器,开展扰动控制仿真。研究表明:在不同外中子源相对强度扰动或堆芯进口温度扰动下,采用模糊PID控制器可实现对堆芯相对功率的良好控制。     

液态熔盐堆堆芯功率内模控制器设计与仿真

内模控制是一种基于过程数学模型进行控制器设计的新型控制策略,具有结构简单、设计直观、无需精确的数学模型、在线调整参数少等优点。为探索内模控制在反应堆控制领域中的应用,以熔盐实验堆堆芯功率控制为例,通过建立熔盐实验堆一回路系统线性化模型,采用内模控制技术,结合粒子群优化算法设计堆芯功率内模控制器。并基于MATLAB/Simulink建立熔盐实验堆一回路仿真系统,开展熔盐实验堆堆芯阶跃反应性扰动下的功率控制研究。结果表明,所设计的堆芯功率内模控制器可很好地控制堆芯功率,实现系统的快速稳定。     

液态熔盐堆堆芯功率内模控制器设计与仿真

内模控制是一种基于过程数学模型进行控制器设计的新型控制策略,具有结构简单、设计直观、无需精确的数学模型、在线调整参数少等优点。为探索内模控制在反应堆控制领域中的应用,以熔盐实验堆堆芯功率控制为例,通过建立熔盐实验堆一回路系统线性化模型,采用内模控制技术,结合粒子群优化算法设计堆芯功率内模控制器。并基于MATLAB/Simulink建立熔盐实验堆一回路仿真系统,开展熔盐实验堆堆芯阶跃反应性扰动下的功率控制研究。结果表明,所设计的堆芯功率内模控制器可很好地控制堆芯功率,实现系统的快速稳定。     

基于多节点模型的液态熔盐堆堆芯功率控制

液态熔盐堆以流动的氟化物作为燃料,燃料熔盐靠主泵驱动在主回路系统中流动,采用控制棒对堆芯功率进行控制。为研究液态熔盐堆堆芯功率控制,基于多节点建模方法,将熔盐实验堆堆芯划分为9个节点区域,建立熔盐实验堆堆芯非线性模型,并对模型进行线性化。基于堆芯线性化模型,采用PID控制方法设计堆芯功率控制系统,对堆芯反应性扰动等工况开展控制研究。结果表明,基于堆芯多节点模型设计的堆芯功率PID控制器可以实现对液态熔盐堆堆芯功率的良好控制。     

基于堆芯线性化模型的液态熔盐堆功率控制研究

液态熔盐堆中熔盐燃料依托主泵驱动在一回路中流动,在流动过程中造成了反应性损失,直接引起堆芯功率变化。考虑到熔盐燃料流动对堆芯功率控制的影响,建立了堆芯非线性模型,并对模型进行线性化处理。基于堆芯线性化模型,采用线性二次型高斯/回路传输（LQG/LTR）技术设计堆芯功率控制系统。以熔盐实验堆为例,开展堆芯反应性扰动控制研究。结果表明,采用堆芯线性化模型和LQG/LTR技术可以实现对液态熔盐堆堆芯功率的控制。      

核电厂反应堆冷却剂平均温度预测控制及仿真研究

针对核电厂反应堆冷却剂平均温度控制对象,采用冷却剂平均温度的非参数模型,设计动态矩阵控制器(DMC)。采用用于过程控制的对象连接与嵌入(OPC)技术与核电仿真模型连接,构建用于冷却剂平均温度控制仿真研究的平台,在矩阵实验室(MATLAB)环境下针对小范围负荷波动设计动态矩阵预测控制器。仿真得到冷却剂平均温度的跟踪曲线与冷却剂平均温度调节棒(R棒)的变化曲线。通过堆芯轴向功率分布偏差,验证该预测控制算法在满足优化控制性能的同时,保证了反应堆功率分布的安全合理性。     

核反应堆堆芯功率模糊切换控制系统开发及应用

为利用不同类型控制器的性能优势,基于堆芯模糊多模型,利用比例-积分-微分(PID)控制器和模糊控制器,结合T-S型模糊规则设计模糊切换控制器。以三里岛核电站压水堆堆型堆芯为例,建立一套堆芯功率模糊切换控制系统并开展仿真研究。结果表明,与传统PID控制器相比,所设计的堆芯模糊切换控制器更适用于堆芯反应性阶跃扰动和堆芯冷却剂进口温度阶跃扰动下的堆芯功率控制。     

基于CPSO滚动优化的堆芯功率自适应预测控制

In view of the nonlinear and reactive constraint of nuclear reactors in the process of variable power, this paper proposes an improved generalized predictive control (JGPC) for core power control. The JGPC calculates the predicted output value by predicting the model parameters and recursive relationships. At the same time, chaos particle swarm optimization (CPSO), which is improved by the sinusoidal chaos strategy and nonlinear inertia weight, is applied to the rolling optimization of JGPC. In the process of optimization, the reactive constraint are dealt with by setting optimization boundary and chaos strategy. The controlled auto-regressive integral moving average (CARIMA) model of core power is established as the JGPC prediction model, and the forgetting factor recursive least squares (FFRLS) method is used to identify the model parameters online. The JGPC controller is simulated and validated based on MATLAB platform. The results show that the controller can make the core power follow the set value quickly and steadily under the condition of satisfying the constraint, and has a certain anti-interference ability.     

Load following control and global stability analysis for PWR core based on multi-model,LQG, IAGA and flexibility idea

The work is to design a nonlinear Pressurized Water Reactor (PWR) core load following control system and analyze the global stability of this system. On the basis of modeling a nonlinear PWR core, linearized models of the core at five power levels are chosen as local models of the core to substitute the nonlinear core model in the global range of power level. The combination control strategy of the Linear Quadratic Gaussian (LQG) control and the Proportional Integral Derivative (PID) control with an optimization process of Improved Adaptive Genetic Algorithm (IAGA) proposed is used to contrive a combined controller with the robustness of a core local model as a local controller of the nonlinear core. Based on the local models and local controllers, the flexibility idea of modeling and control is presented to design a decent controller of the nonlinear core at a random power level. A nonlinear core model and a flexibility controller at a random power level compose a core load following control subsystem. The combination of core load following control subsystems at all power levels is the core load following control system. The global stability theorem is deduced to define that the core load following control system is globally asymptotically stable within the whole range of power level. Finally, the core load following control system is simulated and the simulation results show that the control system is effective.     

基于NSGA-Ⅱ算法的核反应堆功率LQG控制器设计

反应堆功率控制系统的设计与核电厂的安全性和经济性息息相关。为提高其功率控制性能,本研究以某压水堆核电厂为研究对象,建立了其非线性动态数学模型,推导了其状态空间模型;采用线性二次型高斯（LQG）最优控制方法,设计了堆芯功率控制器;进一步基于遗传算法NSGA-Ⅱ对LQR权重系数进行了多目标优化;将本文所设计的控制器与传统PID控制器进行了典型工况的仿真对比。结果表明,与传统PID控制器相比,基于NSGA-Ⅱ方法优化的LQG控制器不但响应快速、控制精度高、稳定性好,而且具有良好的鲁棒性,能获得更优越的堆芯功率控制效果。     

Robust nonlinear model predictive control for nuclear power plants in load following operations with bounded xenon oscillations

One of the important operations in nuclear power plants is load-following in which imbalance of axial power distribution induces xenon oscillations. These oscillations must be maintained within acceptable limits otherwise the nuclear power plant could become unstable. Therefore, bounded xenon oscillation considered to be a constraint for the load-following operation. In this paper, a robust nonlinear model predictive control for the load-following operation problem is proposed that ensures xenon oscillations are kept bounded within acceptable limits. The proposed controller uses constant axial offset (AO) strategy to maintain xenon oscillations to be bounded. The constant AO is a robust state constraint for load-following problem. The controller imposes restricted state constraints on the predicted trajectory during optimization which guarantees robust satisfaction of state constraints without restoring to a min-max optimization problem. Simulation results show that the proposed controller for the load-following operation is so effective so that the xenon oscillations kept bounded in the given region.     

Research reactor power controller design using an output feedback nonlinear receding horizon control method

A constrained, output feedback nonlinear receding horizon control (NRHC) method is applied to design a research reactor power controller. The method uses a nonlinear plant model subject to state, control and terminal set constraints; a nonlinear cost function; and a high gain observer. The controller regulates reactor power from 1% to 100% of full power; considers known disturbances, such as reactivity insertions and changes in core inlet flow and temperature; and includes upper limits constraints on neutron flux, neutron flux rate, core outlet temperature and core inlet–outlet temperature difference. Simulation results show an excellent performance for power regulation and known disturbances rejection: all process variables are kept within the admissible limits avoiding the actuation of the safety systems.     

Application of Fuzzy Logic Controller to Load-Follow Operations in Pressurized Water Reactors

The fuzzy logic controller was developed to control load-follow operations in pressurized water reactors. The reactor core characteristics change according to different fuel cycles or core exposures, thus making a nonlinear time-varying control problem. This proposed method, however, does not require a mathematical model to design the controller, and so avoids redesigning or tuning controller gain for various cores. Clearly, this method is very suitable for reactor load-following operation control. The control system has two subsystems: one is to track the desired power, and the other is to keep axial offset close to the target value. Both controllers use fuzzy logic: one is the conventional type, and the other uses fuzzy logic to tune the parameters of the controller so the controller can correspond to various core characteristics. Simulation results show that the control system performs well for different cores, and so this system is useful for load-follow operation.     

T-S型模糊切换控制器在堆芯功率控制中的应用#br# #br#

The traditional PID controller is used to control the core power, which has the problems of large overshoot and long regulating time in the control process. In order to solve this problem, based on the core transfer function model, the PD controller, the PID controller and the fuzzy controller are weighted and switched by T-S fuzzy rules, and T-S fuzzy switching controller is designed. Taking the core power control of a lead cooled fast reactor as an example, a T-S fuzzy switching control system of the core power is established to simulate the relative power setpoint value step and the core inlet coolant temperature disturbance. The results show that the T-S fuzzy switching controller designed based on the core transfer function model can achieve a good control of the core power.     

T-S型模糊切换控制器在堆芯功率控制中的应用

采用传统比例-积分-微分(PID)控制器开展堆芯功率控制,控制过程中存在超调量大、调节时间长的问题。为解决这一问题,基于堆芯传递函数模型,采用T-S型模糊规则对比例-微分(PD)控制器、PID控制器、模糊控制器进行加权及切换,设计T-S型模糊切换控制器。以铅冷快堆堆芯功率控制为例,建立堆芯功率T-S型模糊切换控制系统,开展堆芯相对功率设定值阶跃、堆芯冷却剂进口温度扰动仿真。结果表明,基于堆芯传递函数模型设计的T-S型模糊切换控制器可以实现对堆芯功率的良好控制。