Wyniki wyszukiwania - BazTech

1

Simulating heat-transfer processes in two-phase heat-utilizer at heat pipes

Kulikova N., Redko A.

Structure and Environment

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2014

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Vol. 6, no. 2

35--43

EN

The choice of rational heat-utilizer heating scheme is a very current problem of energy saving when using boiler units. This article proposes the heat computation technique of heat exchanger at heat pipes with deep combustion - product cooling in boilers and water steam condensation. In addition, the construction scheme of heat exchanger made with two units in which the heat pipes are filled with different working medium is described. The numerical study results of heat carrier temperature and pressure distribution, namely: combustion products and water being heated according to counterflow - heat exchanger length are presented. The efficiency of two-phase heat-utilizer is determined.

2

Nonlinear model predictive control of a boiler unit: a fault tolerant control study

Patan K., Korbicz J.

International Journal of Applied Mathematics and Computer Science

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2012

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Vol. 22, no. 1

225-237

EN

This paper deals with a nonlinear model predictive control designed for a boiler unit. The predictive controller is realized by means of a recurrent neural network which acts as a one-step ahead predictor. Then, based on the neural predictor, the control law is derived solving an optimization problem. Fault tolerant properties of the proposed control system are also investigated. A set of eight faulty scenarios is prepared to verify the quality of the fault tolerant control. Based of different faulty situations, a fault compensation problem is also investigated. As the automatic control system can hide faults from being observed, the control system is equipped with a fault detection block. The fault detection module designed using the one-step ahead predictor and constant thresholds informs the user about any abnormal behaviour of the system even in the cases when faults are quickly and reliably compensated by the predictive controller.

3

Robust fault detection and accommodation of the boiler unit using state space neural networks

Czajkowski A., Patan K.

Pomiary Automatyka Kontrola

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2011

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R. 57, nr 11

1428-1435

EN

The paper deals with application of state space neural network models to fault detection and accommodation of a boiler unit. The work describes two aspects. The first one is the fault detection. In this paper three methods for fault diagnosis, namely: simple and adaptive threshold as well as more robust method which is model error modelling, are described and compared. The second part of the paper presents the approach to fault accommodation based on the so-called instantaneous linearization of the already trained nonlinear state space model of the system. With the obtained linear model it is possible to derive a new control law of the boiler unit in order to eliminate the fault effect in the case of faults. All data used in experiments are collected from the boiler unit simulator implemented in Matlab/Simulink.

PL

Artykuł dotyczy zastosowania modelu sztucznej sieci neuronowej w przestrzeni stanów do wykrywania i kompensacji uszkodzeń w układzie sterowania zbiornikiem przepływowym. Do wykrycia uszkodzenia zostały zaproponowane i doświadczalnie przetestowane trzy metody. Dwie pierwsze metody czyli progowanie proste oraz adaptacyjne polegają na obserwacji sygnału residuum i podejmowaniu decyzji przy przekroczeniu zadanego dopuszczalnego progu przez wartość tego sygnału. Trzecia metoda opiera się na zastosowaniu dodatkowego modelu dynamicznego do modelowania błędu modelu podstawowego w celu określenia zakresu niepewności jego pracy. W przypadku przekroczenia tego zakresu, można uznać, że wystąpiło uszkodzenie. Drugim podjętym przez autorów tematem jest problem kompensacji wykrytego uszkodzenia. W pracy opisuje się podejście oparte na tzw. chwilowej linearyzacji nauczonego w trybie off-line nieliniowego modelu systemu. Na podstawie zlinearyzowanego modelu możliwe jest wyznaczenie nowego prawa sterowania w celu wyeliminowania wpływu uszkodzenia w przypadku wystąpienia awarii. Wszystkie dane wykorzystywane do celów doświadczalnych są zbierane z symulatora zbiornika zrealizowanego w pakiecie Matlab/Simulink.