Modelica.Electrical.Machines.Losses

Information

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

Package Content

Name	Description
FrictionParameters	Parameter record for friction losses
BrushParameters	Parameter record for brush losses
StrayLoadParameters	Parameter record for stray load losses
CoreParameters	Parameter record for core losses
Friction	Model of angular velocity dependent friction losses
InductionMachines	Loss models for induction machines
DCMachines	Loss models for DC machines

Modelica.Electrical.Machines.Losses.FrictionParameters

Information

Parameter record for Friction losses.

Extends from Modelica.Icons.Record (Icon for records).

Parameters

Type	Name	Default	Description
Power	PRef		Reference friction losses at wRef [W]
AngularVelocity	wRef		Reference angular velocity that the PRef refer to [rad/s]
Real	power_w	2	Exponent of friction torque w.r.t. angular velocity

Modelica definition

record FrictionParameters "Parameter record for friction losses"
  extends Modelica.Icons.Record;
  parameter Modelica.SIunits.Power PRef(min=0, start=0) 
    "Reference friction losses at wRef";
  parameter Modelica.SIunits.AngularVelocity wRef(displayUnit="1/min", min=Modelica.Constants.small) 
    "Reference angular velocity that the PRef refer to";
  parameter Real power_w(min=Modelica.Constants.small) = 2 
    "Exponent of friction torque w.r.t. angular velocity";
  final parameter Modelica.SIunits.Torque tauRef = if (PRef<=0) then 0 else PRef / wRef 
    "Reference friction torque at reference angular velocity";
  final parameter Real linear = 0.001 
    "Linear angular velocity range with respect to reference angular velocity";
  final parameter Modelica.SIunits.AngularVelocity wLinear = linear*wRef 
    "Linear angular velocity range";
  final parameter Modelica.SIunits.Torque tauLinear = if (PRef<=0) then 0 else tauRef*(wLinear/wRef)^power_w 
    "Torque corresponding with linear angular velocity range";
end FrictionParameters;

Modelica.Electrical.Machines.Losses.BrushParameters

Information

Parameter record for threephase Brush and DC Brush losses.

Extends from Modelica.Icons.Record (Icon for records).

Parameters

Type	Name	Default	Description
Voltage	V		Total voltage drop of brushes for currents > ILinear [V]
Current	ILinear		Current indicating linear voltage region of brush voltage drop [A]

Modelica definition

record BrushParameters "Parameter record for brush losses"
  extends Modelica.Icons.Record;
  parameter Modelica.SIunits.Voltage V(start=0) 
    "Total voltage drop of brushes for currents > ILinear";
  parameter Modelica.SIunits.Current ILinear(start=0.01) 
    "Current indicating linear voltage region of brush voltage drop";
end BrushParameters;

Modelica.Electrical.Machines.Losses.StrayLoadParameters

Information

Parameter record for threephase and DC stray load losses.

Extends from Modelica.Icons.Record (Icon for records).

Parameters

Type	Name	Default	Description
Power	PRef		Reference stray load losses at IRef and wRef [W]
Current	IRef		Reference RMS current that PRef refers to [A]
AngularVelocity	wRef		Reference angular velocity that PRef refers to [rad/s]
Real	power_w	1	Exponent of stray load loss torque w.r.t. angular velocity

Modelica definition

record StrayLoadParameters "Parameter record for stray load  losses"
  extends Modelica.Icons.Record;
  parameter Modelica.SIunits.Power PRef(min=0, start=0) 
    "Reference stray load losses at IRef and wRef";
  parameter Modelica.SIunits.Current IRef(min=Modelica.Constants.small) 
    "Reference RMS current that PRef refers to";
  parameter Modelica.SIunits.AngularVelocity wRef(displayUnit="1/min", min=Modelica.Constants.small) 
    "Reference angular velocity that PRef refers to";
  parameter Real power_w(min=Modelica.Constants.small) = 1 
    "Exponent of stray load loss torque w.r.t. angular velocity";
  final parameter Modelica.SIunits.Torque tauRef = if (PRef<=0) then 0 else PRef / wRef 
    "Reference friction torque at reference angular velocity and reference current";
end StrayLoadParameters;

Modelica.Electrical.Machines.Losses.CoreParameters

Information

Parameter record for core losses of induction machines and core losses of DC machines.

Extends from Modelica.Icons.Record (Icon for records).

Parameters

Type	Name	Default	Description
Integer	m		Number of phases (1 for DC, 3 for induction machines)
Power	PRef		Reference core losses at reference inner voltage VRef [W]
Voltage	VRef		Reference inner RMS voltage that reference core losses PRef refer to [V]
AngularVelocity	wRef		Reference angular velocity that reference core losses PRef refer to [rad/s]

Modelica definition

record CoreParameters "Parameter record for core losses"
  extends Modelica.Icons.Record;
  parameter Integer m "Number of phases (1 for DC, 3 for induction machines)";
  parameter Modelica.SIunits.Power PRef(min=0, start=0) 
    "Reference core losses at reference inner voltage VRef";
  parameter Modelica.SIunits.Voltage VRef(min=Modelica.Constants.small) 
    "Reference inner RMS voltage that reference core losses PRef refer to";
  parameter Modelica.SIunits.AngularVelocity wRef(min=Modelica.Constants.small) 
    "Reference angular velocity that reference core losses PRef refer to";
  // In the current implementation ratioHysterisis = 0 since hysteresis losses are not implemented yet
  final parameter Real ratioHysteresis(min=0, max=1, start=0.775) = 0 
    "Ratio of hysteresis losses with respect to the total core losses at VRef and fRef";
  final parameter Modelica.SIunits.Conductance GcRef =  if (PRef<=0) then 0 else PRef / VRef^2 / m 
    "Reference conductance at reference frequency and voltage";
  final parameter Modelica.SIunits.AngularVelocity wMin=1e-6*wRef;
end CoreParameters;

Modelica.Electrical.Machines.Losses.Friction

Information

The friction losses are considered by the equations

   tau / tauRef = (+w / wRef) ^ power_w    for w > +wLinear
 - tau / tauRef = (-w / wRef) ^ power_w    for w < -wLinear

with

  tauRef * wRef = PRef

being the friction torque at the referenc angular velocity wRef. The exponent power_w is approximately 1.5 for axial ventilation and approximately 2.0 for radial ventilation.

For stability reasons the friction torque tau is approximated by a linear curve

  tau / tauLinear = w / wLinear

with

  tauLinear = tauRef*(wLinear/wRef) ^ power_w

in the range -wLinear ≤ w ≤ wLinear with wLinear = 0.001 * wRef. The relationship of torque and angular velocity is depicted in Fig. 1

Fig. 1: Friction loss torque versus angular velocity for power_w = 2

See also

FrictionParameters

If it is desired to neglect friction losses, set frictionParameters.PRef = 0 (this is the default).

Extends from Machines.Interfaces.FlangeSupport (Shaft and support).

Parameters

Type	Name	Default	Description
FrictionParameters	frictionParameters		Friction loss parameters

Connectors

Type	Name	Description
Flange_a	flange	Shaft end
Flange_a	support	Housing and support
HeatPort_a	heatPort	Heat port to model heat flow

Modelica definition

model Friction "Model of angular velocity dependent friction losses"
  extends Machines.Interfaces.FlangeSupport;
  parameter FrictionParameters frictionParameters "Friction loss parameters";
  Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a heatPort 
    "Heat port to model heat flow";
equation 
  if (frictionParameters.PRef<=0) then
    tau = 0;
  else
    tau = -smooth(1,if w >= +frictionParameters.wLinear then 
                      +frictionParameters.tauRef*(+w/frictionParameters.wRef)^frictionParameters.power_w else 
                    if w <= -frictionParameters.wLinear then 
                      -frictionParameters.tauRef*(-w/frictionParameters.wRef)^frictionParameters.power_w else 
                      frictionParameters.tauLinear*(w/frictionParameters.wLinear));
  end if;
  heatPort.Q_flow = tau*w;
end Friction;