Soft Constrained MPC on Water Level Control in Steam Generator of a Nuclear Power Plant
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摘要: 核电站的蒸汽发生器(U-tube steam generator,UTSG)水位控制对核反应堆安全运行至关重要.模型预测控制(Model predictive control,MPC)具有内在的约束处理能力,是UTSG水位控制的有效方法.然而在大范围变功率情况下,水位硬约束会降低水位的控制性能,甚至导致系统不稳定.本文基于UTSG的分段线性输入输出模型,设计了水位软约束MPC.离线计算终端约束集,减少在线计算量,保证稳定性;引入两种松弛变量来放宽水位约束和终端约束集;在蒸汽流量扰动和功率变化情况下的仿真结果表明了算法的有效性.Abstract: In the nuclear power plant, the water level control of the U-tube steam generator (UTSG) plays a vital role on the safety of the nuclear reactor operation. Model predictive control (MPC) has been a quite effective way of controlling the water level of UTSG, due to its water level constraint handling ability. However, when the nuclear power plant is working under wide load changing condition, the water level hard constraint may deteriorate the closed-loop control performance and even cause instability. This paper presents a soft constrained MPC on the UTSG water level control based on the linear parameter varying (LPV) model. A terminal constraint set is computed off-line to reduce the online computation burden and ensure stability. Slack variables are introduced in the MPC formulation to relax the water level and terminal constraint in a straightforward way. Simulations under both the steam disturbance and the power-level changing show the effectiveness of the proposed controllers.
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Key words:
- Model predictive control /
- soft constraint /
- steam generator /
- non-minimum phase system
1) 本文责任编委 梅生伟 -
表 1 软约束MPC计算量
Table 1 The computation of soft constrained MPC
状态个数 控制量个数 控制时域 决策变量个数 等式约束个数 不等式约束个数 最小时间 最大时间 平均时间 5 1 10 32 50 86 90 ms 302 ms 147 ms -
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