Robust and Gain-Scheduled PID Controller Design for Condensing Boilers by Linear Programming

Abstract

This paper addresses the water temperature control in condensing domestic boilers. The main challenge of this process under the controller design perspective is the fact that the dynamics of condensing boilers are strongly affected by the demanded water flow rate. Two approaches are presented in this paper. First, a robust PI controller is designed that stabilizes and achieves good performance for closed-loop system for a wide range of the water flow rate. Then, it is shown that if the water flow rate information is used to update the controller gains, a technique known as gain-scheduled control, the performance can be significantly improved. Several models of a boiler in different water flow rate are identified in collaboration with Honeywell, and the effectiveness of the results are illustrated by simulation.

PID robust gain-scheduled controller design

“…A controller formulation inspired by the Youla-Kučera parametrization to propose a controller structure and design approach that allow the gain-scheduling of linear control designs such that a robustly stable nonlinear closed-loop control system is achieved. A robust PID controller is designed in [5].The main feature of the proposed method is that the stability, robustness margin and some performance specification are guaranteed by linear constraints in the Nyquist diagram. The condensing boiler is described by the first order model with a time delay in [6], the problem of attenuation of sinusoidal disturbances with uncertain and arbitrarily time-varying frequencies is solved by synthesis of LPV controller using the L 2 gain method.…”

Iterative Procedure for Tuning Decentralized PID Controllers

“…(11) This is done by geometry analysis as showed in Oliveira and Karimi (2012). Similar analysis can be done using equivalent open-loop process, l eq (jω k ) = g eq jj (jω k )c j (jω k ).…”

WGC Based Robust and Gain Scheduling PI Controller Design for Condensing Boilers

“…For a detailed review of gain scheduling analysis and design refer to the study carried out by Leith and Leithead [9]. Recently, in their study, Oliveire and Karimi [10] have designed a robust PID controller for the condensing boiler problem by using the method given in [11]. The main feature of the method is that the stability, robustness margins, and some performance specifications are guaranteed by linear constraints in the Nyquist diagram.…”