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

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 ambience. Simple machine-specific thermal ambience 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

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

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 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 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 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 Content

Name	Description
LinearTemperatureCoefficient20	Linear temperature coefficient with choices
Constants	Material Constants
convertAlpha	Converts alpha from temperature 1 (default 20 degC) to temperature 2
convertResistance	Converts resistance from reference temperature to an actual temperature
linearTemperatureDependency	Converts a value (e.g. resistance) from reference temperature to an actual temperature
InductionMachines	Thermal parts of induction machines
SynchronousMachines	Thermal parts of synchronous machines
DCMachines	Thermal parts of DC machines
ThermalAmbientTransformer	Thermal ambient for transformers

Modelica.Electrical.Machines.Thermal.LinearTemperatureCoefficient20

Linear temperature coefficient with choices

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

Name	Description
alpha1	Temperature coefficient at temperature 1 (default: 20 degC) [1/K]
T2	Temperature 2 [K]
T1	Temperature 1 (default: 20 degC) [K]

Outputs

Name	Description
alpha2	Temperature coefficient at TRef [1/K]

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

Name	Description
RRef	Resistance at TRef [Ohm]
TRef	Reference temperature [K]
alpha20	Temperature coefficient at 20 degC [1/K]
T	Actual temperature [K]

Outputs

Name	Description
R	Actual resistance at T [Ohm]

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

Name	Description
RRef	Value at TRef
TRef	Reference temperature [K]
alpha20	Temperature coefficient at 20 degC [1/K]
T	Actual temperature [K]

Outputs

Name	Description
R	Actual value at T

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

Name	Description
m	Number of phases
useTemperatureInputs	If true, temperature inputs are used; else, temperatures are constant
T1	Temperature of primary windings [K]
T2	Temperature of secondary windings [K]

Connectors

Name	Description
thermalPort
TPrimary	Temperature of primary windings [K]
TSecondary	Temperature of secondary windings [K]

Automatically generated Thu Oct 1 16:07:42 2020.