A method for the preliminary synthesis of a complex multiloop control system

1955 ◽  
Vol 74 (3) ◽  
pp. 129-134 ◽  
Author(s):  
D. J. Povejsil ◽  
A. M. Fuchs
Keyword(s):  
Control System ◽  
Multiloop Control ◽  
Multiloop Control System

scholarly journals Comparison of Steady State and Dynamic Interaction Measurements in Multiloop Control Systems

2005 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
Renanto Handogo ◽  
Avon T. H. ◽  
Joko Lelono
Keyword(s):  
Control System ◽  
Steady State ◽  
Control Systems ◽  
Dynamic Process ◽  
Dynamic Interaction ◽  
Time Constants ◽  
Relative Gain ◽  
Relative Gain Array ◽  
Multiloop Control ◽  
Multiloop Control System

The applicability of the steady-state Relative Gain Array (RGA) to measure dynamic process interactions in a multiloop control system was investigated. Several transfer function matrices were chosen, and the gains, time constants, and dead times of their elements were varied to represent the systems with dominant dynamic interactions. It was shown that the steady-state RGA method predicted the controller pairing accurately if the pairing elements recommended by RGA had the bigger gains and the same or smaller time constants compared to other elements in the corresponding rows. When these conditions were not met, the RGA would give a wrong result, and dynamic interaction measurements, such as the Average Dynamic Gain Array (ADGA) and the Inverse Nyquist Array (lNA), should be used instead to determine the best controller pairing in a multiloop control system. Keywords: Control pairing, dynamic process interaction, multiloop control systems, Relative Gain Array (RGA), and steady state.

Decoupling Method for PI Controllers via Setpoint Modification Applied to HVAC Systems

2018 ◽  
Author(s):  
Timothy I. Salsbury ◽  
John M. House ◽  
Carlos F. Alcala
Keyword(s):  
Control System ◽  
Predictive Control ◽  
Energy Systems ◽  
Hvac Systems ◽  
Test Results ◽  
Simulation Test ◽  
Decoupling Method ◽  
Pi Controllers ◽  
Multiloop Control ◽  
Multiloop Control System

The method described in this paper addresses the problem of interaction in a control system that consists of multiple legacy PI(D) controllers. In these systems, it is often not possible to intercept the signals between the controllers and plant and replacement with multivariable alternatives such as model predictive control (MPC) may not be viable from a cost perspective. To address these issues, we propose a decoupling method that involves first changing the tuning of the controllers and then dynamically adjusting the setpoints. The method enables decoupling of a multiloop control system via setpoint adjustment which can be carried out without having to re-engineer any of the legacy controllers. The paper focuses on the application area of energy systems in buildings where costs are constrained and PID multiloop configurations are prevalent. Simulation test results are presented from two systems to demonstrate the improvement in control achieved with the method.

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