Robust block roots assignment in linear discrete-time sliding mode control for a class of multivariable system: gas turbine power plant application

2018 ◽  
Vol 41 (5) ◽  
pp. 1216-1232 ◽  
Author(s):  
Bachir Nail ◽  
Abdellah Kouzou ◽  
Ahmed Hafaifa

This paper deals with the development of a new extended robust control algorithm based on the assignment of robust block roots to extended linear discrete-time sliding mode control; matrix fraction description (MFD) theory is used to improve the performance of the proposed control algorithm and make it more robust. To validate the proposed control algorithm, an application on a gas turbine system (GE MS5001P), which is used in electrical power generation plants, is presented in this paper. An autoregressive model with exogenous excitation is obtained for the studied system, based on the left MFD multivariable least-squares estimator, using real data obtained on-site in order to obtain a minimum-order model with optimum validation criteria. The main objective of the implementation of the proposed control algorithm within the presented application is to ensure stability in the dynamic behaviour of the gas turbine system. Furthermore, a comparison with some classical and modern controllers has been made to prove the effectiveness and robustness of the proposed control algorithm.

2015 ◽  
Vol 66 (2) ◽  
pp. 61-69 ◽  
Author(s):  
Santolo Meo ◽  
Vincenzo Sorrentino

Abstract In the paper a new discrete-time integral sliding mode control (DISMC) with disturbances compensation and reduced chattering for grid-connected inverter is proposed for active and reactive power regulation. Differently by many SMC proposed in literature that have a time-continuous formulation in spite have been implemented with digital processor, the proposed DISMC is fully formulated in discrete-time, taking into account the effects introduced by a microprocessor-based implementation. As will be demonstrated such approach consents to reduce the chattering about the sliding manifold within a boundary layer of O(T2) thickness instead of O(T) (being T the sampling period of the control algorithm). Moreover it introduces a correction of the control vector which eliminates the influence of modeling error and external disturbances improving stability and robustness of the controlled system. Constant converter switching frequency is achieved by using space vector modulation, which eases the design of the ac harmonic filter. In the paper, after a detailed formalization of the proposed control algorithm, several numerical and experimental results on a three-phase grid-connected inverter prototype are shown, proving the effectiveness of the control strategy.


2018 ◽  
Vol 14 (02) ◽  
pp. 103 ◽  
Author(s):  
Huifang Kong ◽  
Yao Fang

<p class="0abstract"><span lang="EN-US">The control of nonlinear system is the hotspot in the control field. The paper proposes an algorithm to solve the tracking and robustness problem for the discrete-time nonlinear system. The completed control algorithm contains three parts. First, the dynamic linearization model of nonlinear system is designed based on Model Free Adaptive Control, whose model parameters are calculated by the input and output data</span><span lang="EN-US"> of system</span><span lang="EN-US">. Second, the model error is estimated using the Quasi-sliding mode control algorithm</span><span lang="EN-US">, hence, the whole model of system is estimated</span><span lang="EN-US">. Finally, the neural network </span><span lang="EN-US">PID </span><span lang="EN-US">controller is designed to get the optimal control law. The convergence and BIBO stability of the control system is proved by the Lyapunov function. The simulation results </span><span lang="EN-US">in</span><span lang="EN-US"> the </span><span lang="EN-US">linear and </span><span lang="EN-US">nonlinear system validate the effectiveness and robustness of the algorithm.</span><span lang="EN-US"> The robustness </span><span lang="EN-US">effort </span><span lang="EN-US">of </span><span lang="EN-US">Quasi-sliding mode control algorithm</span><span lang="EN-US"> in nonlinear system is also verified in the paper.</span></p>


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Qian Xu ◽  
H. P. Du ◽  
B. He ◽  
T. H. Yan ◽  
W. H. Li ◽  
...  

This paper proposed a new sliding mode control algorithm for discrete-time systems with matched uncertainty. The new control algorithm is characterized by a new discrete switching surface. Although the exponential reaching law can reduce oscillation, the control effectiveness will be suppressed when the rate of change of disturbance is high. The exponential reaching law cannot force the system states to approach sliding surface sk=0. In order to solve the contradiction between guaranteeing the basic property of quasi-sliding mode and reducing oscillation, a new discrete reaching law is proposed to improve the reaching process of discrete exponent reaching laws. The proposed method not only can force system state to approach the sliding surface sk=0 in less width of the switching manifold than existing studies, but also can alleviate chattering when the system representative points are near zero point. Simulation results are provided to validate the feasibility and reasonability of the method.


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