scholarly journals Adaptive second-order nonsingular terminal sliding mode power-level control for nuclear power plants

2021 ◽  
Author(s):  
Jiuwu Hui ◽  
Jingqi Yuan
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Sliding Mode ◽  
Power Level ◽  
Second Order ◽  
Level Control ◽  
Terminal Sliding Mode ◽  
Nonsingular Terminal Sliding Mode

Smooth second-order nonsingular terminal sliding mode control for reusable launch vehicles

2014 ◽  
Vol 7 (1) ◽  
pp. 95-110 ◽  
Author(s):  
Shaobo Ni ◽  
Jiayuan Shan
Keyword(s):  
Finite Time ◽  
Sliding Mode ◽  
Tracking Error ◽  
Second Order ◽  
Convergence Time ◽  
Control Input ◽  
Terminal Sliding Mode ◽  
Content Type ◽  
Nonsingular Terminal Sliding Mode ◽  
Attitude Tracking

Purpose – The purpose of this paper is to present a sliding mode attitude controller for reusable launch vehicle (RLV) which is nonlinear, coupling, and includes uncertain parameters and external disturbances. Design/methodology/approach – A smooth second-order nonsingular terminal sliding mode (NTSM) controller is proposed for RLV in reentry phase. First, a NTSM manifold is proposed for finite-time convergence. Then a smooth second sliding mode controller is designed to establish the sliding mode. An observer is utilized to estimate the lumped disturbance and the estimation result is used for feedforward compensation in the controller. Findings – It is mathematically proved that the proposed sliding mode technique makes the attitude tracking errors converge to zero in finite time and the convergence time is estimated. Simulations are made for RLV through the assumption that aerodynamic parameters and atmospheric density are perturbed. Simulation results demonstrate that the proposed control strategy is effective, leading to promising performance and robustness. Originality/value – By the proposed controller, the second-order sliding mode is established. The attitude tracking error converges to zero in a finite time. Meanwhile, the chattering is alleviated and a smooth control input is obtained.

A novel adaptive second-order nonsingular terminal sliding mode guidance law design

2020 ◽  
Vol 234 (16) ◽  
pp. 2263-2273
Author(s):  
Shuai Xu ◽  
Min Gao ◽  
Dan Fang ◽  
Yi Wang ◽  
Baochen Li
Keyword(s):  
Finite Time ◽  
Sliding Mode ◽  
Initial Conditions ◽  
Dynamic Control ◽  
Small Neighborhood ◽  
Lyapunov Stability Theory ◽  
Second Order ◽  
Terminal Sliding Mode ◽  
Guidance Law ◽  
Nonsingular Terminal Sliding Mode

Aiming at the problem of missile attacking ground target in pitch plane, combined with a composite fast nonsingular terminal sliding mode, a new adaptive finite-time stable guidance law with attack angle constraint is designed based on the second-order sliding mode control. The improved extended state observer is used to estimate the uncertainties and compensate the control quantity, and the dynamic control gains are designed to avoid the problem about “excessive estimation” of the parameter upper limit. According to the Lyapunov stability theory, it is proved that the system states can converge into a small neighborhood near the equilibrium point in a finite time. Monte Carlo simulation is carried out by randomly generating initial conditions, which proves that the guidance law has strong adaptability to different initial conditions and has good guidance precision.

scholarly journals Power Level Control of Nuclear Power Plant Based on Asymptotical State Observer under Neutron Sensor Fault

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Liming Zhang ◽  
Hongyun Xie ◽  
Qizhi Duan ◽  
Chao Lu ◽  
Jixue Li ◽  
...  
Keyword(s):  
Control System ◽  
Power Control ◽  
Control Systems ◽  
Nuclear Power ◽  
Power Plants ◽  
Power Level ◽  
Level Control ◽  
Power Control System ◽  
Neutron Sensors ◽  
And Control

Power level control is one of the critical functions in the instrument and control system of nuclear power plants (NPPs). In most power level control systems of NPPs, the power level or average neutron flux in reactor cores provided by out-of-core neutron sensors are usually measured as feedback of power control systems, while, as critical measuring devices, there is a risk of damage to out-of-core neutron sensors. For improving the operation reliability of NPPs under the neutron sensors’ failure, a power control system based on power observer is developed in this work. The simulation based on NPP simulator shows the power control system based on the observer is effective when neutron sensors fail.

scholarly journals Development and verification of methods for predicting the frequency of self-oscillations in swirling coolant flows of nuclear power plants

2021 ◽  
Vol 2088 (1) ◽  
pp. 012037
Author(s):  
KN Proskuryakov ◽  
AV Anikeev
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Power Level ◽  
Primary Circuit ◽  
Frequency Bandwidth ◽  
Mechanical Vibrations ◽  
Oscillation Frequencies ◽  
Necessary And Sufficient ◽  
Nuclear Power Plant Unit

Abstract Methods and algorithms for calculating the frequency of self-oscillations in swirling coolant flows of nuclear power plants with VVER reactors have been developed. The frequency of self-oscillations occurring in the acoustic sections of the primary circuit and their connections in the starting modes of the power unit and when operating at the rated power level is predicted. It is established that the self-oscillation frequencies can fall into the frequency bandwidth of mechanical vibrations and vibrations of the reactor plant’s internal devices. It is shown that in order to prevent the resonance of self-oscillations of the coolant with the vibration frequencies of internal devices, it is necessary and sufficient to take the frequency of self-oscillations outside the bandwidth of the vibration frequency of structures. The results of verification of the results of forecasting the frequency of self-oscillations in swirling coolant flows at a nuclear power plant unit with VVER are presented. The application of the developed technique shows that the pendulum oscillations of the VVER - 1200 body are caused by an increase in the parameters of the coolant and the geometric dimensions of the VVER - 1200 reactor compared to VVER-1000.

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