Package Modelica.​Electrical.​Machines.​Thermal
Library with models for connecting thermal models

Information

Thermal concept

Each machine model is equipped with a machine-specific conditional thermalPort. If useThermalPort == false, a machine-specific thermal ambient prescribing constant temperatures is used inside the machine. If useThermalPort == true, a thermal model or machine-specific thermal ambient prescribing the temperatures has to be connected from outside. On the other hand, all losses are dissipated to this internal or external thermal ambient.

The machine specific thermal connector contains heatPorts for all relevant loss sources of the machine type, although some of the loss sources are not yet implemented; these heatPorts are left unconnected inside the machine, i.e., the HeatFlowRate is zero, but they have to be connected to a constant temperature source in the internal or external thermal ambient. Simple machine-specific thermal ambients for constant temperatures (useTemperatureInputs == false) or temperatures prescribed via signal inputs (useTemperatureInputs == true) are provided in this package.

Loss sources

Up to now, only Ohmic losses in stator and rotor windings are implemented. They are modeled as linearly temperature dependent resistors:

   ROperational = RRef * (1 + alphaRef * (TOperational - TRef))

Parameters:

• Resistance RRef at reference temperature
• Reference temperature TRef
• Linear temperature coefficient alpha20 at 20°C
• Operational temperature TOperational (if useThermalPort == false; otherwise, the operational temperature is provided via the heatPort)
• Nominal temperature TNominal (required for DC machines to calculate the turns ratio)

The linear temperature coefficient alpha20 at 20°C = 293.15 K has to be converted to reference temperature TRef:

                        alpha20
  alphaRef = -------------------------------
              1 + alpha20 * (TRef - 293.15)

For this reason, the function convertAlpha is provided. In sub-package Constants linear temperature coefficients at 20°C for commonly used materials are defined.

Backwards compatibility

• The default / start values of all resistances are left unchanged.
• The default / start values of all reference temperatures are set to 20°C.
• The default / start values of all linear temperature coefficients are set to 0.
• The default / start values of all operational temperatures are set to 20°C.
• The default / start values of all nominal temperatures are set to 20°C.

Machine specific thermalPorts

Asynchronous induction machine with squirrel cage

• heatPortStatorWinding[m]: m=3 heatPorts for the m=3 stator phases
• heatPortRotorWinding: heatPort for the rotor cage
• heatPortStatorCore: stator core losses (not yet fully implemented)
• heatPortRotorCore: rotor core losses (not yet connected/implemented)
• heatPortStrayLoad: stray load losses
• heatPortFriction: friction losses

Asynchronous induction machine with slipring rotor

• heatPortStatorWinding[m]: m=3 heatPorts for the m=3 stator phases
• heatPortRotorWinding[m]: m=3 heatPorts for the m=3 rotor phases
• heatPortBrush: brush losses (not yet connected/implemented)
• heatPortStatorCore: stator core losses (not yet fully implemented)
• heatPortRotorCore: rotor core losses (not yet fully implemented)
• heatPortStrayLoad: stray load losses
• heatPortFriction: friction losses

Synchronous induction machine with permanent magnets

• heatPortStatorWinding[m]: m=3 heatPorts for the m=3 stator phases
• heatPortRotorWinding: conditional (useDamperCage=true/false) heatPort for the damper cage
• heatPortPermanentMagnet: permanent magnet losses (not yet connected/implemented)
• heatPortStatorCore: stator core losses (not yet fully implemented)
• heatPortRotorCore: rotor core losses (not yet connected/implemented)
• heatPortStrayLoad: stray load losses
• heatPortFriction: friction losses

Synchronous induction machine with electrical excitation

• heatPortStatorWinding[m]: m=3 heatPorts for the m=3 stator phases
• heatPortRotorWinding: conditional (useDamperCage=true/false) heatPort for the damper cage
• heatPortExcitation: electrical excitation
• heatPortBrush: brush losses
• heatPortStatorCore: stator core losses (not yet fully implemented)
• heatPortRotorCore: rotor core losses (not yet connected/implemented)
• heatPortStrayLoad: stray load losses
• heatPortFriction: friction losses

Synchronous induction machine with reluctance rotor

• heatPortStatorWinding[m]: m=3 heatPorts for the m=3 stator phases
• heatPortRotorWinding: conditional (useDamperCage=true/false) heatPort for the damper cage
• heatPortStatorCore: stator core losses (not yet fully implemented)
• heatPortRotorCore: rotor core losses (not yet connected/implemented)
• heatPortStrayLoad: stray load losses
• heatPortFriction: friction losses

DC machine with permanent magnets

• heatPortArmature: armature losses
• heatPortPermanentMagnet: permanent magnet losses (not yet connected/implemented)
• heatPortBrush: brush losses
• heatPortCore: armature core losses
• heatPortStrayLoad: stray load losses
• heatPortFriction: friction losses

DC machine with electrical (shunt) excitation

• heatPortArmature: armature losses
• heatPortExcitation: electrical (shunt) excitation
• heatPortBrush: brush losses
• heatPortCore: armature core losses
• heatPortStrayLoad: stray load losses
• heatPortFriction: friction losses

DC machine with serial excitation

• heatPortArmature: armature losses
• heatPortSeriesExcitation: electrical series excitation
• heatPortBrush: brush losses
• heatPortCore: armature core losses
• heatPortStrayLoad: stray load losses
• heatPortFriction: friction losses

DC machine with compound excitation (not yet implemented)

• heatPortArmature: armature losses
• heatPortShuntExcitation: electrical (shunt) excitation
• heatPortSeriesExcitation: electrical series excitation
• heatPortBrush: brush losses
• heatPortCore: armature core losses
• heatPortStrayLoad: stray load losses
• heatPortFriction: friction losses

Transformers

• heatPort1[m]: m=3 heatPorts for the m=3 primary phases
• heatPort2[m]: m=3 heatPorts for the m=3 secondary phases
• heatPortCore: iron core losses (not yet connected/implemented)

Extends from Modelica.​Icons.​Package (Icon for standard packages).

Package Contents

Type Modelica.​Electrical.​Machines.​Thermal.​LinearTemperatureCoefficient20
Linear temperature coefficient with choices

Extends from Modelica.​SIunits.​LinearTemperatureCoefficient.

Attributes

Function Modelica.​Electrical.​Machines.​Thermal.​convertAlpha
Converts alpha from temperature 1 (default 20 degC) to temperature 2

Information

From the temperature coefficient alpha1 at temperature T1 (default 20 degC = 293.15 K) the temperature coefficient alpha2 at temperature T2 is calculated:

                alpha1
  alpha2 = ------------------------
            1 + alpha1 * (T2 - T1)

Extends from Modelica.​Icons.​Function (Icon for functions).

Inputs

Outputs

Function Modelica.​Electrical.​Machines.​Thermal.​convertResistance
Converts resistance from reference temperature to an actual temperature

Information

From the temperature coefficient alpha20 at 20 degC (equals to 293.15 K) the parameter alphaRef at TRef

                        alpha20
  alphaRef = -------------------------------
              1 + alpha20 * (TRef - 293.15)

is determined; using this value, actual resistance R with respect to the actual temperature T is calculated by

   R
  ------ = 1 + alphaRef * (T - TRef)
   RRef

where RRef is the resistance at the reference temperature TRef.

Extends from Modelica.​Icons.​Function (Icon for functions).

Inputs

Outputs

Function Modelica.​Electrical.​Machines.​Thermal.​linearTemperatureDependency
Converts a value (e.g. resistance) from reference temperature to an actual temperature

Information

This is the same function as Modelica.Electrical.Machines.Thermal.convertResistance but without physical units for input RRef and result R. This avoids problems if the function is used to calculate linear temperature dependency for other values than resistances.

From the temperature coefficient alpha20 at 20 degC (equals to 293.15 K) the parameter alphaRef at TRef

                        alpha20
  alphaRef = -------------------------------
              1 + alpha20 * (TRef - 293.15)

is determined; using this value, actual value (e.g. resistance R) with respect to the actual temperature T is calculated by

   R
  ------ = 1 + alphaRef * (T - TRef)
   RRef

where RRef is the value (e.g. resistance) at the reference temperature TRef.

Extends from Modelica.​Icons.​Function (Icon for functions).

Inputs

Outputs

Model Modelica.​Electrical.​Machines.​Thermal.​ThermalAmbientTransformer
Thermal ambient for transformers

Information

Thermal ambient for transformers to prescribe winding temperatures either constant or via signal connectors. Additionally, all losses = heat flows are recorded.

Parameters

Connectors