Designing separately the different levels of the control algorithms can help to keep a
well-organized control structure. Cascaded control algorithms are advisable for a
complex system, because they allow to divide the system into several levels. For instance,
the arrangement given below can be used:
Level 2:
Smart control
Level 1:
Device
controllers
Heating power
Ventilation rate
Artificial lighting
Blind position
Level 3:
Optimization of
level 2
controllers
Parameters
ventil.
user feedback and wishes
radiator
sensors
Figure 3.1: Cascaded control loops diagram.
In this figure, three levels are considered for the control algorithm:
1
The level-1 control block allows to control directly the technical devices provided
in the particular case, translating the physical variable at the input (for instance, a
blind position) into actuators commands (for instance in the same case, a
command "blind up" or "blind down");
2
The level-2 control block includes the knowledge base, and provides the desired
setpoint for the building devices taking into account the information given by the
sensors and the predicted future behaviour of the whole system.
3
Finally, the level-3 control loop allows a continuous adaptation of the control
parameters for the lower loop controllers, taking into account both an overall
"cost function" (which represents the penalty for energy used and thermal, visual
and air quality discomfort level), and reactions of the user.
Summary :
Designing separately the different levels of the control algorithms can help to keep a well-organized control structure. In this figure, three levels are considered for the control algorithm: 1 The level-1 control block allows to control directly the technical devices provided in the particular case, translating the physical variable at the input (for instance, a blind position) into actuators commands (for instance in the same case, a command "blind up"
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leel,into,leels,controllers,instance,system,loop,sensors,cascaded,allows,algorithms,account,block