Inverse model-based real-time control for temperature uniformity of RTCVD

1999 ◽  
Vol 12 (1) ◽  
pp. 87-101 ◽  
Author(s):  
A. Theodoropoulou ◽  
E. Zafiriou ◽  
R.A. Adomaitis
Keyword(s):  
Real Time ◽  
Inverse Model ◽  
Temperature Uniformity ◽  
Real Time Control ◽  
Model Based ◽  
Time Control

A New Flexible Rapid Thermal Processing System

1995 ◽  
Vol 389 ◽  
Author(s):  
K. C. Saraswat ◽  
Y. Chen ◽  
L. Degertekin ◽  
B. T. Khuri-Yakub
Keyword(s):  
Control System ◽  
Real Time ◽  
Processing System ◽  
Process Conditions ◽  
Temperature Uniformity ◽  
Real Time Control ◽  
Wafer Temperature ◽  
Time Control ◽  
Wide Range ◽  
Optical Flux

ABSTRACTA highly flexible Rapid Thermal Multiprocessing (RTM) reactor is described. This flexibility is the result of several new innovations: a lamp system, an acoustic thermometer and a real-time control system. The new lamp has been optimally designed through the use of a “virtual reactor” methodology to obtain the best possible wafer temperature uniformity. It consists of multiple concentric rings composed of light bulbs with horizontal filaments. Each ring is independently and dynamically controlled providing better control over the spatial and temporal optical flux profile resulting in excellent temperature uniformity over a wide range of process conditions. An acoustic thermometer non-invasively allows complete wafer temperature tomography under all process conditions - a critically important measurement never obtained before. For real-time equipment and process control a model based multivariable control system has been developed. Extensive integration of computers and related technology for specification, communication, execution, monitoring, control, and diagnosis demonstrates the programmability of the RTM.

scholarly journals Model-Based Optimisation and Control Strategy for the Primary Drying Phase of a Lyophilisation Process

Pharmaceutics ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 181 ◽  
Author(s):  
Brecht Vanbillemont ◽  
Niels Nicolaï ◽  
Laurens Leys ◽  
Thomas De Beer
Keyword(s):  
Real Time ◽  
Control Strategy ◽  
Freeze Drying ◽  
Fixed Time ◽  
Chamber Pressure ◽  
Interface Temperature ◽  
Real Time Control ◽  
Choked Flow ◽  
Model Based ◽  
Time Control

The standard operation of a batch freeze-dryer is protocol driven. All freeze-drying phases (i.e., freezing, primary and secondary drying) are programmed sequentially at fixed time points and within each phase critical process parameters (CPPs) are typically kept constant or linearly interpolated between two setpoints. This way of operating batch freeze-dryers is shown to be time consuming and inefficient. A model-based optimisation and real-time control strategy that includes model output uncertainty could help in accelerating the primary drying phase while controlling the risk of failure of the critical quality attributes (CQAs). In each iteration of the real-time control strategy, a design space is computed to select an optimal set of CPPs. The aim of the control strategy is to avoid product structure loss, which occurs when the sublimation interface temperature ( T i ) exceeds the the collapse temperature ( T c ) common during unexpected disturbances, while preventing the choked flow conditions leading to a loss of pressure control. The proposed methodology was experimentally verified when the chamber pressure and shelf fluid system were intentionally subjected to moderate process disturbances. Moreover, the end of the primary drying phase was predicted using both uncertainty analysis and a comparative pressure measurement technique. Both the prediction of T i and end of primary drying were in agreement with the experimental data. Hence, it was confirmed that the proposed real-time control strategy is capable of mitigating the effect of moderate disturbances during batch freeze-drying.

Model-based, real-time control of electrical power systems

1996 ◽  
Vol 26 (4) ◽  
pp. 470-482 ◽  
Author(s):  
A.J. Gonzalez ◽  
R.A. Morris ◽  
F.D. McKenzie ◽  
D.J. Carreira ◽  
B.K. Gann
Keyword(s):  
Power Systems ◽  
Real Time ◽  
Electrical Power ◽  
Real Time Control ◽  
Electrical Power Systems ◽  
Model Based ◽  
Time Control
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