blockGain

Identify the gain of a first-order plus time-delay model

Information

This block calculates the gain of a first-order plus time-delay model.

k = Iy/Iu,

Iy is calculated by

Iy = ∫ u(t) dt;

where u(t) is the relay output at t (see details in Buildings.Controls.OBC.Utilities.PIDWithAutotuning.Relay.Controller).

Iu is calculated by

Iu = ton yhig - toffylow,

where yhig and ylow are constants related to an asymmetric relay output. ton and toff are the length of the on period and the off period of the same asymmetric relay output, respectively.

References

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

Parameters

TypeNameDefaultDescription
RealyHigHigher value for the output (assuming the reference output is 0)
RealyLowLower value for the output (assuming the reference output is 0)

Connectors

TypeNameDefaultDescription
Buildings.Controls.OBC.CDL.Interfaces.RealInputuRelay controller output, (measurement - setpoint)
Buildings.Controls.OBC.CDL.Interfaces.RealInputtOnLength for the on period
Buildings.Controls.OBC.CDL.Interfaces.RealInputtOffLength for the off period
Buildings.Controls.OBC.CDL.Interfaces.BooleanInputtriStaRelay tuning status, true if the tuning starts
Buildings.Controls.OBC.CDL.Interfaces.RealOutputkGain

Revisions

  • June 1, 2022, by Sen Huang:
    First implementation.