Control Station was the first supplier of control loop
performance monitoring (CLPM) technology to join OSIsoft's Partner EcoSphere, and the company is the only CLPM vendor to capitalize on the PI Asset Framework.
Remind that the aim is to analyze the robust stability of the control loop
that contains feedback controllers (4) and the heating-cooling system (1) with the uncertain parameters (3).
"PAS is leveraging our alarm management experience, data analytics around alarms and control loop
performance to come up with a new generation of cyber anomaly detection that no one else is looking at," Habibi said.
As an actuator in the control loop
, a frequency drive is used.
According to Figure 1, it is clear that [mathematical expression not reproducible] can be treated as an output perturbation acting on the main control loop
. Thus, the effect of [mathematical expression not reproducible] over the main output can be modeled using the sensitivity function of the main control loop
Figure 5 shows a typical control block of a converter station employing a dual-loop structure: a fast inner current control loop
and a slower outer control loop
Let current control loop
, the current loop dynamics were set to 20 times  faster than the voltage dynamics with N=20.
In this section, a cascaded control loop
architecture is proposed as a solution to reduce the problem of hunting in building HVAC systems.
A typical current control loop
is based on proportional-integral (PI) controller, highly appreciated in industry due to its simplicity and reliability.
The open current control loop
is described using transfer function:
Due to the potential for interaction between the building pressurization and return fan control loops
, extra care must be taken in selecting the parameters that determine the dynamic response of the digital filters and feedback controllers.
The main controllers are designed via classical SISO synthesis methods (Ziegler Nichols step response method, method of desired model) (1), (7-10) and also via polynomial approach (pole placement method) for SISO control loop