Hierarchically Structured Components with Inside and Outside Connectors

NOTE: In order to simulate the PartialDCMotor. model below, you first need to evaluate the declarations in sections 1-5 below. This is easily done by selecting these cells (to the right) and pushing shift-return as usual.

1 Types from Modelica.SIunits

The following are different types from the library Modelica.SIunits used by the PartDCMotorCircuit

1.1 Electrical units

type ElectricPotential = Real; type ElectricCurrent = Real(quantity = "ElectricCurrent", unit = "A"); type Resistance = Real(quantity = "Resistance", unit = "Ohm", min = 0); type Inductance = Real(quantity = "Inductance", unit = "H", min = 0); type Voltage = ElectricPotential; type Current = ElectricCurrent;

1.2 Mechanical units

type Force = Real(quantity = "Force", unit = "N"); type Angle = Real(quantity = "Angle", unit = "rad", displayUnit = "deg"); type Torque = Real(quantity = "Torque", unit = "N.m"); type AngularVelocity = Real(quantity = "AngularVelocity", unit = "rad/s", displayUnit = "rev/min"); type AngularAcceleration = Real(quantity = "AngularAcceleration", unit = "rad/s2"); type MomentOfInertia = Real(quantity = "MomentOfInertia", unit = "kg.m2");

1.3 Other units

type Length = Real(quantity = "Length", unit = "m"); type Time = Real(quantity = "Time", unit = "s"); type Distance = Length(min = 0); type Position = Length;

2 Electrical Connectors

connector Pin "Pin of an electrical component" Voltage v "Potential at the pin"; flow Current i "Current flowing into the pin"; end Pin; //From Modelica.Electrical.Analog.Interfaces
connector PositivePin "Positive pin of an electrical component" Voltage v "Potential at the pin"; flow Current i "Current flowing into the pin"; end PositivePin; //From Modelica.Electrical.Analog.Interfaces
connector NegativePin "Negative pin of an electrical component" Voltage v "Potential at the pin"; flow Current i "Current flowing into the pin"; end NegativePin; //From Modelica.Electrical.Analog.Interfaces

3 Mechanical Connectors

connector RotFlange_a "1D rotational flange (filled square)" Angle phi "Absolute rotational angle of flange"; flow Torque tau "Torque in the flange"; end RotFlange_a; //From Modelica.Mechanics.Rotational.Interfaces
connector RotFlange_b "1D rotational flange (filled square)" Angle phi "Absolute rotational angle of flange"; flow Torque tau "Torque in the flange"; end RotFlange_b; //From Modelica.Mechanics.Rotational.Interfaces

4 Block Signal Connectors

connector InPort "Connector with input signals of type Real" parameter Integer n = 1 "Dimension of signal vector"; input Real signal[n] "Real input signals"; end InPort; // From Modelica.Blocks.Interfaces
connector OutPort "Connector with output signals of type Real" parameter Integer n = 1 "Dimension of signal vector"; output Real signal[n] "Real output signals"; end OutPort; // From Modelica.Blocks.Interfaces

5 Components

5.1 Electrical Components

partial model TwoPin // Same as OnePort in Modelica.Electrical.Analog.Interfaces "Component with two electrical pins p and n and current i from p to n" Voltage v "Voltage drop between the two pins (= p.v - n.v)"; Current i(fixed=true) "Current flowing from pin p to pin n"; PositivePin p; NegativePin n; equation v = p.v - n.v; 0 = p.i + n.i; i = p.i; end TwoPin;
class Resistor "Ideal linear electrical Resistor" extends TwoPin; // Same as OnePort parameter Real R(unit = "Ohm") "Resistance"; equation R*i = v; end Resistor; // From Modelica.Electrical.Analog.Basic
class Inductor "Ideal linear electrical Inductor" extends TwoPin; // Same as OnePort parameter Real L(unit = "H") "Inductance"; equation v = L*der(i); end Inductor; // From Modelica.Electrical.Analog.Basic
class Ground "Ground node" Pin p; equation p.v = 0; end Ground; // From Modelica.Electrical.Analog.Basic
model SignalVoltage "Generic Voltage source using the input signal as source Voltage" extends TwoPin; // Same as OnePort InPort inPort(n=1); equation inPort.signal[1] = v; end SignalVoltage; // From Modelica.Electrical.Analog.Sources

5.2 Mechanical Components

partial model Rigid // Rotational class Rigid "Base class for the rigid connection of two rotational 1D flanges" Angle phi(fixed=true) "Absolute rotation angle of component"; RotFlange_a rotFlange_a "(left) driving flange (axis directed into plane)"; RotFlange_b rotFlange_b "(right) driven flange (axis directed out of plane)"; equation rotFlange_a.phi = phi; rotFlange_b.phi = phi; end Rigid; // From Modelica.Mechanics.Rotational.Interfaces
model Inertia "1D rotational component with inertia" extends Rigid; parameter MomentOfInertia J = 1 "Moment of inertia"; AngularVelocity w(fixed=true) "Absolute angular velocity of component"; AngularAcceleration a "Absolute angular acceleration of component"; equation w = der(phi); a = der(w); J*a = rotFlange_a.tau + rotFlange_b.tau; end Inertia; //From Modelica.Mechanics.Rotational

5.3 Electromechanical Components

model EMF "Electromotoric force (electric/mechanic transformer)" extends TwoPin; parameter Real k(unit = "N.m/A") = 1 "Transformation coefficient"; AngularVelocity w "Angular velocity of rotFlange_b"; RotFlange_b rotFlange_b; // Rotational Flange_b equation w = der(rotFlange_b.phi); v = k*w; rotFlange_b.tau = - k*i; end EMF; // From Modelica.Electrical.Analog.Basic

5.4 Signal Block Components

partial block MO "Multiple Output continuous control block" parameter Integer nout = 1 "Number of outputs"; OutPort outPort(n = nout) "Connector of Real output signals"; protected Real n[nout] = outPort.signal; end MO; // From Modelica.Blocks.Interfaces
block Step "Generate step signals of type Real" extends MO(nout = 1); parameter Real height = 1 "Height of steps"; parameter Real offset = 0 "Offset of output signals"; parameter Time startTime = 0 "Output = offset for time < startTime"; equation outPort.signal[1] = offset + (if time < startTime then 0 else height); end Step; // Version simplified from Step in Modelica.Blocks.Sources

6 Partial DC Motor

Complex systems are naturally described as hierachical structures often many levels deep. We would like to create a structured library component class that captures most of the essentials of DC motor circuit. This is done in the incomplete PartialDCMotor.

model PartialDCMotor InPort inPort; // Outside signal connector RotFlange_b rotFlange_b; // Outside rotational flange connector Inductor inductor1(L=0.2); Resistor resistor1(R=10); Ground ground1; EMF emf1; SignalVoltage signalVoltage1; equation connect(inPort, signalVoltage1.inPort); connect(signalVoltage1.p, resistor1.p); connect(resistor1.n, inductor1.p); connect(signalVoltage1.n, ground1.p); connect(ground1.p, emf1.n); connect(inductor1.n, emf1.p); connect(emf1.rotFlange_b, rotFlange_b); end PartialDCMotor;
model PartDCMotorCircuit Step step1; PartialDCMotor partialDCMotor1; Inertia inertia1(J=1); equation connect(step1.outPort, partialDCMotor1.inPort); connect(partialDCMotor1.rotFlange_b, inertia1.rotFlange_a); end PartDCMotorCircuit;

7 Simulation of PartDCMotorCircuit

simulate( PartDCMotorCircuit, stopTime=100 )
plot( inertia1.w )