Vollständige Modale Synthese robust hyperstabiler Mehrgrößenregelkreise (Complete Modal Synthesis of Robustly Hyperstable Multivariable Control-loops)

2000 ◽  
Vol 48 (12/2000) ◽  
Author(s):  
Gabriele Schmitt-Braess
Keyword(s):  
Multivariable Control ◽  
Control Loops ◽  
Modal Synthesis

scholarly journals An Advanced Control System for Turbofan Engine: Multivariable Control and Fuzzy Logic (Application to the M88-2 Engine)

1995 ◽  
Author(s):  
Alain Garassino
Keyword(s):  
Fuzzy Logic ◽  
Control Systems ◽  
Performance Index ◽  
Multivariable Control ◽  
Outer Loop ◽  
Turbofan Engine ◽  
Stall Margin ◽  
Control Loops ◽  
Advanced Control ◽  
Fuzzy Supervisor

The search for better performance of present and future turbofan engine involves an increase on the number of variable geometries and thus of control loops. As we can not or do not want to disregard the interaction between loops any more, the future control systems will therefore be multivariable. The aim of the architecture of multivariable control presented here is to optimize a performance index during transients. This architecture consists of an inner loop which optimizes the performance index taking in account the limitations, an outer loop which brings the nominal steady-state offsets to zero and a trajectory which allows to take into account the topping schedule limitation. This basic architecture can be improved by fuzzy supervisor. Indeed, two control outputs are generated according to the description above: - the first one optimizes the thrust and does not care very much about LP stall margin limitation, - the second one optimizes again the thrust and strongly takes low pressure stall margin limitation into account. The fuzzy logic then allows to do a compromise between these two control outputs according to the engine state. Simulation results showing the efficiency of the method are given.

There Reduction of alkali loss in an ash leaching system

TAPPI Journal ◽  
2017 ◽  
Vol 16 (7) ◽  
pp. 383-391
Author(s):  
CARLA CÉLIA ROSA MEDEIROS ◽  
FLÁVIA AZEVEDO SILVA ◽  
SAULO GODOY PIGNATON ◽  
ESTANISLAU VICTOR ZUTAUTAS ◽  
KLEVERSON FIGUEIREDO
Keyword(s):  
Solid Waste ◽  
Air Emissions ◽  
Recovery Cycle ◽  
Chloride Level ◽  
Control Loops ◽  
Kraft Mill ◽  
Recovery Boiler ◽  
Ash Leaching

There are many points in a kraft mill where the alkaline compounds are purged from the process. Several effluents, solid waste, and air emissions contain alkali, which leads to the necessity of chemical makeups to maintain the liquor balance. The main loss of alkali at the Veracel mill is present in the wastewater from the recovery boiler; more precisely, it is from the ash leaching system, which represents 80% of the total losses. To minimize the alkaline losses while keeping the chloride level in the recovery cycle under control, a project was developed at Veracel. Key actions were taken by adjusting the control loops of the ash leaching system, mainly on the slurry density and purge control. These adjustments led to a decrease in alkali losses and to an increase of treated ash, and kept the chloride level of the recovery boiler dust at 2.6%.

Multivariable Control of a Furnace: LQS Versus GMC

1989 ◽  
Author(s):  
Brian W. Surgenor ◽  
Tim Hesketh
Keyword(s):  
Multivariable Control

Practical Methods for Robust Multivariable Control

1988 ◽  
Author(s):  
Michael G. Safonov ◽  
Edmond A. Jonckheere
Keyword(s):  
Multivariable Control

Using advanced control, post-denitrification and equalisation to improve the performance of a submerged filter

2000 ◽  
Vol 41 (4-5) ◽  
pp. 177-184 ◽  
Author(s):  
K.H. Sørensen ◽  
D. Thornberg ◽  
K.F. Janning
Keyword(s):  
Energy Consumption ◽  
Total N ◽  
Control Loops ◽  
Effluent Quality ◽  
Advanced Control ◽  
Before And After ◽  
And Control ◽  
Side Flow ◽  
Configuration Control ◽  
Control Post

In 1998, the capacity of the BIOSTYR® submerged biofilter at Nyborg WWTP was extended from 48,000 PE to 60,000 PE including advanced sensor based control, post-denitrification in BIOSTYR® and equalization of side flows. The existing configuration with 8 BIOSTYR® DN/N cells is based on pre-denitrification and an internal recirculation of 600–800%. The extended plant comprises 7 BIOSTYR® DN/N cells with 50–225% recirculation followed by 3 BIOSTYR DN cells for post-denitrification. The advanced control loops include blower control, control of the number of active cells (stand-by), automatic switch to high load configuration, control of the side flow equalization, control of the internal recirculation and control of the external carbon source dosing. In this paper, the achieved improvements are documented by comparing influent and effluent data, methanol and energy consumption from comparable periods before and after the extension. Although the nitrogen load to the plant was increased by 20% after the extension, the effluent quality has improved significantly with a reduction of Total-N from 7–8 mg/l to 3–4 mg/l. Simultaneously, the methanol consumption has been reduced by more than 50% per kg removed nitrogen. The energy consumption remained constant although the nitrogen load was increased by 20% and the inflow by 80%.

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