Pressure regulation in nonlinear hydraulic networks by positive controls

Abstract

We investigate an industrial case study of a system distributed over a network, namely, a large-scale hydraulic network which underlies a district heating system. The network comprises an arbitrarily large number of components (valves, pipes, and pumps). After introducing the model for this class of networks, we show how to achieve semiglobal practical pressure regulation at designated points of the network by proportional control laws which use local information only. In the analysis, the presence of positivity constraints on the actuators (centrifugal pumps) is explicitly taken into account. Furthermore, motivated by the need of transmitting the values taken by the control laws to the pumps of the network in order to distribute the control effort, we study the pressure regulation problem using quantized controllers. The findings are supported by experimental results.

Global practical stabilisation of large-scale hydraulic networks

“…These flow variables have the property that their values can be set independently from other flows in the network. The independent flow variables coincide with the flows through the chords of the graph [3]. To each chord in the graph, a fundamental (flow) loop is associated, and along this loop Kirchhoffs voltage law holds.…”

“…This more specific class is motivated by the presence of turbulent 2 flows in the system [3]. The class of functions, which will be considered, is the following…”

“…The network model has been derived using standard circuit theory [3]. The hydraulic network consists of m components and n end-users (m > n).…”

Modeling of Nonlinear Marine Cooling Systems with Closed Circuit Flow

“…Similar modeling have been carried out in (De Persis and Kallesøe (2009a)) and (De Persis and Kallesøe (2008)), where design of control laws for a system with hydraulic resemblance to the system in this work, is considered. However, since the objective in (De Persis and Kallesøe (2009a)) and (De Persis and Kallesøe (2008)) is to control the pressure at some end users, the constructed model and corresponding controller design only covers the hydraulic part of the system.…”

“…However, since the objective in (De Persis and Kallesøe (2009a)) and (De Persis and Kallesøe (2008)) is to control the pressure at some end users, the constructed model and corresponding controller design only covers the hydraulic part of the system. In our context it is desired to include the thermodynamics of the system, as the temperature of the consumers in the cooling system is of great importance when it comes to set point optimization.…”