.Buildings.Controls.OBC.Utilities.PIDWithAutotuning.Relay.Controller

Information

This block generates a relay output yDif = (u_m - u_s)/r, where u_m is the measurement, u_s is the setpoint and r is the typical range of control error.

This block also generates the control output y, and a boolean relay switch output yOn using the following procedure.

Step 1: Calculate control error,

• If the parameter reverseActing = true, set the control error err = (u_s - u_m)/r, else set err = (u_m - u_s)/r.

Step 2: Calculate y and yOn,

• If err > deaBan and trigger = true, then y = yHig and yOn = true,
• else if err < -deaBan and trigger = true, then y = yLow and yOn = false,
• else, y and yOn are kept as the initial values.

where deaBan is a dead band, yHig and yLow are the higher value and the lower value of the output y, respectively.

References

J. Berner (2017). "Automatic Controller Tuning using Relay-based Model Identification." Department of Automatic Control, Lund University.

Revisions

• March 8, 2024, by Michael Wetter:
  Changed deadband to be consistent within the package.
• March 8, 2024, by Michael Wetter:
  Propagated range of control error r to relay controller.
• December 1, 2023, by Sen Huang:
  Add a parameter reverseActing
  
• June 1, 2022, by Sen Huang:
  First implementation.