Page 27 - Distributed model predictive control for plant-wide systems

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Introduction

1.1 Plant-Wide System
There is a class of systems which are composed of many interacted subsystems’ industrial
fields. Especially with the development of the advanced technology and the increase in the
requirement of products, many new distributed processes have appeared, the processes of pro-
ducing products have become more and more complex, and the scales of industrial processes
have become more and more large. The automation structure for this kind of systems has
changed from the traditional centralized automation system to a decentralized and centralized
automation system, and then to a distributed automation system.
Correspondingly, the control algorithm and control structure for this kind of system change
from centralized control and decentralized control to the distributed control system. The dis-
tributed control refers to a control system where each subsystem is controlled by an individual
controller, and these controllers communicate with other subsystem-based controllers and are
coordinated according to the exchanged information for obtaining good global performance
or some special common goals. So far, the distributed control, especially the DMPC, has been
studied and are still being studied by many scientists, and many theories and algorithms have
been developed. We think it is the right time to introduce the distributed control to more stu-
dents and engineers.
To make it more clear which kind of system is suitable for distributed control, we give some
examples as follows.

1. Wind power generation farm
In a wind turbine power generation farm, as shown in Figure 1.1, wind turbines are spa-
tially distributed. The output wind flow rate of each wind turbine decreases with increasing
generated power. It affects the input wind flow rate of the downstream wind turbines, and
then their dynamics. In this way, these wind turbines interact with each other. For the
automation system, each wind turbine is controlled by an individual controller. And these
controllers are connected by a network (fieldbus) and are able to communicate with each
other by the network.

Distributed Model Predictive Control for Plant-Wide Systems, First Edition. Shaoyuan Li and Yi Zheng.
© 2015 John Wiley & Sons (Asia) Pte Ltd. Published 2015 by John Wiley & Sons (Asia) Pte Ltd.