Modelica.Electrical.Machines.Losses.DCMachines

Loss models for DC machines

Information

Extends from Modelica.Icons.VariantsPackage (Icon for package containing variants).

Package Content

Name	Description
Brush	Model considering voltage drop of carbon brushes
brushVoltageDrop	Voltage drop of carbon brushes
StrayLoad	Model of stray load losses dependent on current and speed
Core	Model of core losses

Modelica.Electrical.Machines.Losses.DCMachines.Brush

Model considering voltage drop of carbon brushes

Information

Model of voltage drop and losses of carbon brushes. For currents between -ILinear and ILinear the voltage drop shows a linear behavior as depicted in Fig. 1. For positive currents greater or equal than ILinear the voltage drop equals V. For negative currents less or equal than -ILinear the voltage drop equals -V.

Fig. 1: Model of voltage drop of carbon brushes

Note:

The voltage drop v is the total voltage drop of all series connected brushes.

See also

BrushParameters

If it is desired to neglect brush losses, set brushParameters.V = 0 (this is the default).

Extends from Modelica.Electrical.Analog.Interfaces.OnePort (Component with two electrical pins p and n and current i from p to n), Modelica.Thermal.HeatTransfer.Interfaces.PartialElementaryConditionalHeatPortWithoutT (Partial model to include a conditional HeatPort in order to dissipate losses, used for textual modeling, i.e., for elementary models).

Parameters

Connectors

Modelica.Electrical.Machines.Losses.DCMachines.brushVoltageDrop

Voltage drop of carbon brushes

Information

Calculates the voltage drop of carbon brushes, according to Brush losses, e.g., used for initial equations.

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

Inputs

Outputs

Modelica.Electrical.Machines.Losses.DCMachines.StrayLoad

Model of stray load losses dependent on current and speed

Information

The stray load loss torque is

  tau = PRef/wRef * (i/IRef)^2 * (w/wRef)^power_w

where i is the current of the machine and w is the actual angular velocity. The dependency of the stray load torque on the angular velocity is modeled by the exponent power_w.

The stray load losses are modeled such way that they do not cause a voltage drop in the electric circuit. Instead, the dissipated losses are considered through an equivalent braking torque at the shaft.

See also

StrayLoad parameters

If it is desired to neglect stray load losses, set strayLoadParameters.PRef = 0 (this is the default).

Extends from Modelica.Electrical.Analog.Interfaces.OnePort (Component with two electrical pins p and n and current i from p to n), Machines.Interfaces.FlangeSupport (Shaft and support), Modelica.Thermal.HeatTransfer.Interfaces.PartialElementaryConditionalHeatPortWithoutT (Partial model to include a conditional HeatPort in order to dissipate losses, used for textual modeling, i.e., for elementary models).

Parameters

Connectors

Modelica.Electrical.Machines.Losses.DCMachines.Core

Model of core losses

Information

Core losses can be separated into eddy current and hysteresis losses. The total core losses can thus be expressed as

  p = PRef * (ratioHysteresis * (wRef / w) + 1 - ratioHysteresis) * (v / VRef)^2

where w is the actual angular velocity and v is the actual voltage. The term ratioHysteresis is the ratio of the hysteresis losses with respect to the total core losses for reference inner voltage and reference angular velocity.

For the voltage and angular velocity range with respect to Fig. 1, the dependency of total core losses on the parameter ratioHysteresis is depicted in Fig. 2.

Fig. 1: Voltage versus angular velocity

Fig. 2: Core losses versus angular velocity with parameter ratioHysteresis

Note

In the current implementation it is assumed that ratioHysteresis = 0. This parameter cannot be changed due to compatibility reasons.

See also

Core loss parameters

Extends from Modelica.Electrical.Analog.Interfaces.OnePort (Component with two electrical pins p and n and current i from p to n), Modelica.Thermal.HeatTransfer.Interfaces.PartialElementaryConditionalHeatPortWithoutT (Partial model to include a conditional HeatPort in order to dissipate losses, used for textual modeling, i.e., for elementary models).

Parameters

Connectors