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:

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 Contents

NameDescription
AsynchronousInductionMachinesThermal parts of asynchronous induction machines
ConstantsMaterial Constants
convertAlphaConverts alpha from temperature 1 (default 20 degC) to temperature 2
convertResistanceConverts resistance from reference temperature to an actual temperature
DCMachinesThermal parts of DC machines
LinearTemperatureCoefficient20Linear temperature coefficient with choices
linearTemperatureDependencyConverts a value (e.g. resistance) from reference temperature to an actual temperature
SynchronousInductionMachinesThermal parts of synchronous induction machines
ThermalAmbientTransformerThermal ambient for transformers

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

Extends from Modelica.​SIunits.​LinearTemperatureCoefficient.

Attributes

NameValue
quantity"LinearTemperatureCoefficient"
unit"1/K"
min-Modelica.Constants.inf
maxModelica.Constants.inf
start0.

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

TypeNameDescription
LinearTemperatureCoefficientalpha1Temperature coefficient at temperature 1 (default: 20 degC)
TemperatureT2Temperature 2
TemperatureT1Temperature 1 (default: 20 degC)

Outputs

TypeNameDescription
LinearTemperatureCoefficientalpha2Temperature coefficient at TRef

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

TypeNameDescription
ResistanceRRefResistance at TRef
TemperatureTRefReference temperature
LinearTemperatureCoefficientalpha20Temperature coefficient at 20 degC
TemperatureTActual temperature

Outputs

TypeNameDescription
ResistanceRActual resistance at T

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

TypeNameDescription
RealRRefValue at TRef
TemperatureTRefReference temperature
LinearTemperatureCoefficientalpha20Temperature coefficient at 20 degC
TemperatureTActual temperature

Outputs

TypeNameDescription
RealRActual value at T

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

TypeNameDefaultDescription
Integerm3Number of phases
BooleanuseTemperatureInputsfalseIf true, temperature inputs are used; else, temperatures are constant
TemperatureT1 Temperature of primary windings
TemperatureT2 Temperature of secondary windings

Connectors

TypeNameDescription
ThermalPortTransformerthermalPort 
input RealInputTPrimaryTemperature of primary windings
input RealInputTSecondaryTemperature of secondary windings

Generated 2018-12-12 12:10:15 EST by MapleSim.