Buildings.Controls.Continuous.Examples

Information

This package contains examples for the use of models that can be found in Buildings.Controls.Continuous.

Package Content

Name	Description
LimPID	Test model for PID controller with optional reverse action
PIDHysteresis	Example model for PID controller with hysteresis
PIDHysteresisTimer	Example model for PID controller with hysteresis and timer
SignalRanker	Example model for signal ranker
NumberOfRequests	Example model for block that outputs the number of requests
OffTimer	Example model for off timer

Buildings.Controls.Continuous.Examples.LimPID

Information

This model tests the implementation of the PID controller with optional reverse action. The model limPIDOri is the original implementation of the controller from the Modelica Standard Library. The models limPID and limPIDRev are the implementations from the Buildings library. The model limPIDRev is parameterized to have reverse action. The assertion blocks test whether the results of all three controllers are identical.

Modelica definition

model LimPID 
  "Test model for PID controller with optional reverse action"
  extends Modelica.Icons.Example;

  Modelica.Blocks.Sources.Pulse pulse(period=0.25);
  Buildings.Controls.Continuous.LimPID limPID(
    controllerType=Modelica.Blocks.Types.SimpleController.PID,
    Ti=1,
    Td=1,
    yMax=1,
    yMin=-1,
    initType=Modelica.Blocks.Types.InitPID.InitialState);
  Buildings.Controls.Continuous.LimPID limPIDRev(
    controllerType=Modelica.Blocks.Types.SimpleController.PID,
    reverseAction=true,
    Ti=1,
    Td=1,
    yMax=1,
    yMin=-1,
    initType=Modelica.Blocks.Types.InitPID.InitialState) 
    "Controller with reverse action";
  Modelica.Blocks.Sources.Constant const(k=0.5);
  Modelica.Blocks.Math.Gain gain(k=-1);
  Buildings.Utilities.Diagnostics.AssertEquality assertEquality(threShold=1e-10);
  Modelica.Blocks.Continuous.LimPID limPIDOri(
    controllerType=Modelica.Blocks.Types.SimpleController.PID,
    Ti=1,
    Td=1,
    yMax=1,
    yMin=-1,
    initType=Modelica.Blocks.Types.InitPID.InitialState);
  Buildings.Utilities.Diagnostics.AssertEquality assertEquality1(
                                                                threShold=1e-10);
equation 
  connect(pulse.y, limPID.u_s);
  connect(pulse.y, limPIDRev.u_s);
  connect(const.y, limPID.u_m);
  connect(const.y, limPIDRev.u_m);
  connect(limPIDRev.y, gain.u);
  connect(gain.y, assertEquality.u2);
  connect(limPID.y, assertEquality.u1);
  connect(pulse.y, limPIDOri.u_s);
  connect(const.y, limPIDOri.u_m);
  connect(assertEquality1.u1, limPIDOri.y);
  connect(assertEquality1.u2, limPID.y);
end LimPID;

Buildings.Controls.Continuous.Examples.PIDHysteresis

Information

Example that demonstrates the use of the PID controller with hysteresis. The control objective is to keep the temperature of the energy storage cap at 40°C. The controller con is parameterized to switch on if the control error is bigger than e_on=1. The output of the controller remains above y_min=0.3 until the control error is smaller than e_off=-1, at which time the controller outputs y=0 until the control error is again bigger than 1. The figure below shows the control error con.feeBac.y and the control signal con.y.

Modelica definition

model PIDHysteresis 
  "Example model for PID controller with hysteresis"
  extends Modelica.Icons.Example;

  Buildings.Controls.Continuous.PIDHysteresis con(
    pre_y_start=false,
    controllerType=Modelica.Blocks.Types.SimpleController.PI,
    yMin=0.3,
    Ti=600,
    Td=60);
  Modelica.Blocks.Sources.Constant TSet(k=273.15 + 40, y(unit="K")) "Set point";
  Modelica.Thermal.HeatTransfer.Components.HeatCapacitor cap(C=1000000, T(start=
         313.15, fixed=true));
  Buildings.HeatTransfer.Sources.PrescribedTemperature TBC;
  Modelica.Thermal.HeatTransfer.Components.ThermalConductor theCon(G=20);
  Modelica.Blocks.Math.Gain gain(k=2000);
  Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensor temSen;
  Buildings.HeatTransfer.Sources.PrescribedHeatFlow Q_flow;
  Modelica.Blocks.Sources.Sine sine(
    freqHz=1/86400,
    offset=273.15,
    amplitude=20,
    phase=-1.5707963267949,
    y(unit="K"));
equation 

  connect(TSet.y, con.u_s);
  connect(TBC.port, theCon.port_a);
  connect(theCon.port_b, cap.port);
  connect(con.y, gain.u);
  connect(cap.port, temSen.port);
  connect(temSen.T, con.u_m);
  connect(gain.y, Q_flow.Q_flow);
  connect(Q_flow.port, cap.port);
  connect(sine.y, TBC.T);
end PIDHysteresis;

Buildings.Controls.Continuous.Examples.PIDHysteresisTimer

Information

Example that demonstrates the use of the PID controller with hysteresis and off timer. The example is identical to Buildings.Controls.Continuous.Examples.PIDHysteresis, except that the controller also has an off timer. This timer keeps the control signal at y=0 for a period of minOffTime=1000 seconds. This may be used to avoid short-cycling if the load is small and the system has little heat capacity.

The figure below shows the control error con.feeBac.y and the control signal con.y.

Modelica definition

model PIDHysteresisTimer 
  "Example model for PID controller with hysteresis and timer"
  extends Modelica.Icons.Example;

  Buildings.Controls.Continuous.PIDHysteresisTimer con(
    yMin=0.3,
    minOffTime=10000,
    controllerType=Modelica.Blocks.Types.SimpleController.PI,
    Ti=60,
    Td=10);
  Modelica.Blocks.Sources.Constant TSet(k=273.15 + 40, y(unit="K")) "Set point";
  Modelica.Thermal.HeatTransfer.Components.HeatCapacitor cap(C=100000, T(start=
          293.15, fixed=true));
  Buildings.HeatTransfer.Sources.PrescribedTemperature TBC;
  Modelica.Thermal.HeatTransfer.Components.ThermalConductor theCon(G=10);
  Modelica.Blocks.Math.Gain gain(k=800);
  Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensor temSen;
  Buildings.HeatTransfer.Sources.PrescribedHeatFlow Q_flow;
  Modelica.Blocks.Sources.Sine sine(
    freqHz=1/86400,
    offset=273.15,
    amplitude=20,
    phase=-1.5707963267949);
equation 

  connect(TSet.y, con.u_s);
  connect(TBC.port, theCon.port_a);
  connect(theCon.port_b, cap.port);
  connect(con.y, gain.u);
  connect(cap.port, temSen.port);
  connect(temSen.T, con.u_m);
  connect(gain.y, Q_flow.Q_flow);
  connect(Q_flow.port, cap.port);
  connect(sine.y, TBC.T);
end PIDHysteresisTimer;

Buildings.Controls.Continuous.Examples.SignalRanker

Information

Example that demonstrates the use of the signal ranker model. The figure below shows the input and output signals of the block. Note that sigRan.y[1] ≥ sigRan.y[2] ≥ sigRan.y[3].

Modelica definition

model SignalRanker "Example model for signal ranker"
  extends Modelica.Icons.Example;
  Modelica.Blocks.Sources.Sine sine(freqHz=2);
  Modelica.Blocks.Sources.Pulse pulse(period=0.25);
  Buildings.Controls.Continuous.SignalRanker sigRan(
                                                  nin=3);
  Modelica.Blocks.Sources.ExpSine expSine(freqHz=10, damping=1);
equation 
  connect(sine.y, sigRan.u[1]);
  connect(pulse.y, sigRan.u[2]);
  connect(expSine.y, sigRan.u[3]);
end SignalRanker;

Buildings.Controls.Continuous.Examples.NumberOfRequests

Information

Example that demonstrates the use of the block Buildings.Controls.Continuous.NumberOfRequests. The parameters of the block are such that the output is incremented for each input signal that is strictly larger than 0. The figure below shows the inputs and the output of the block.

Modelica definition

model NumberOfRequests 
  "Example model for block that outputs the number of requests"
  extends Modelica.Icons.Example;
  Buildings.Controls.Continuous.NumberOfRequests numReq(
    nin=2,
    threShold=0,
    kind=0);
  Modelica.Blocks.Sources.Sine sine(freqHz=2);
  Modelica.Blocks.Sources.Pulse pulse(period=0.25);
equation 
  connect(sine.y, numReq.u[1]);
  connect(pulse.y, numReq.u[2]);
end NumberOfRequests;

Buildings.Controls.Continuous.Examples.OffTimer

Information

Example that demonstrates the use of the model Buildings.Controls.Continuous.OffTimer. The input to the two timers are alternating boolean values. Whenever the input becomes false(=0), the timer is reset. The figures below show the input and output of the blocks.

Modelica definition

model OffTimer "Example model for off timer"
  extends Modelica.Icons.Example;

  Modelica.Blocks.Sources.BooleanPulse booleanPulse(period=0.2);
  Buildings.Controls.Continuous.OffTimer offTim1;
  Buildings.Controls.Continuous.OffTimer offTim2;
  Modelica.Blocks.Logical.Not not1;
equation 
  connect(booleanPulse.y, offTim1.u);
  connect(booleanPulse.y, not1.u);
  connect(offTim2.u, not1.y);
end OffTimer;