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.

Test and Simulation System of Multi-Axis Controller

2013 ◽  
Vol 860-863 ◽  
pp. 1069-1072
Author(s):  
Rong Chun Sun ◽  
Yan Xin Yu
Keyword(s):  
Control System ◽  
Error Analysis ◽  
Real Time ◽  
Control Strategy ◽  
Simulation System ◽  
Test Results ◽  
Simulation Test ◽  
Motion Mechanism ◽  
Simulation Unit ◽  
Time Acquisition

To realize the online error analysis and verification of control strategy, it is necessary to simulate the states of the motion mechanism, and accurately to obtain the motion relationship between multi-axis and between motors. So a test and simulation system of multi-axis controller was designed. The system consists of a unit of real-time acquisition and analysis, a simulation unit of motor loads, a motherboard and a computer. Motor driving signals for multi channels are synchronously sampled and analyzed by the unit of acquisition and analysis. Motherboard is used to link the various parts. The working states of motor divers under loads are simulated by simulating the motor loads. In the industrial computer, the control effects of multi-axis control system are displayed by 3D simulation. Test results show that the system is stable and reliable, and has a certain application value.

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.

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