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:

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

Machine specific thermalPorts

Asynchronous induction machine with squirrel cage
Asynchronous induction machine with slipring rotor
Synchronous induction machine with permanent magnets
Synchronous induction machine with electrical excitation
Synchronous induction machine with reluctance rotor
DC machine with permanent magnets
DC machine with electrical (shunt) excitation
DC machine with serial excitation
DC machine with compound excitation (not yet implemented)
Transformers

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

Package Content

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

Modelica.Electrical.Machines.Thermal.LinearTemperatureCoefficient20

Linear temperature coefficient with choices

Modelica.Electrical.Machines.Thermal.convertAlpha 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

NameDescription
alpha1Temperature coefficient at temperature 1 (default: 20 degC) [1/K]
T2Temperature 2 [K]
T1Temperature 1 (default: 20 degC) [K]

Outputs

NameDescription
alpha2Temperature coefficient at TRef [1/K]

Modelica.Electrical.Machines.Thermal.convertResistance 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

NameDescription
RRefResistance at TRef [Ohm]
TRefReference temperature [K]
alpha20Temperature coefficient at 20 degC [1/K]
TActual temperature [K]

Outputs

NameDescription
RActual resistance at T [Ohm]

Modelica.Electrical.Machines.Thermal.linearTemperatureDependency 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

NameDescription
RRefValue at TRef
TRefReference temperature [K]
alpha20Temperature coefficient at 20 degC [1/K]
TActual temperature [K]

Outputs

NameDescription
RActual value at T

Modelica.Electrical.Machines.Thermal.ThermalAmbientTransformer 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

NameDescription
mNumber of phases
useTemperatureInputsIf true, temperature inputs are used; else, temperatures are constant
T1Temperature of primary windings [K]
T2Temperature of secondary windings [K]

Connectors

NameDescription
thermalPort 
TPrimaryTemperature of primary windings
TSecondaryTemperature of secondary windings
Automatically generated Thu Dec 19 17:19:57 2019.