WOLFRAM SYSTEM MODELER

PermeanceActuator

Detailed actuator model for rough magnetic design of actuator and system simulation

Wolfram Language

In[1]:=
`SystemModel["Modelica.Magnetic.FluxTubes.Examples.MovingCoilActuator.Components.PermeanceActuator"]`
Out[1]:=

Information

This information is part of the Modelica Standard Library maintained by the Modelica Association.

In the ConstantActuator model the force F is strictly proportional to the current i as indicated by the converter constant c. However, there is an additional non-linear force component in such an actuator that is due to the dependency of the coil inductance L on the armature position x. The inductance increases as the armature moves into the stator. The total force is

```    1  2 dL
F = - i  --  + c i
2    dx
```

Both force components are properly considered with a simple permeance model as shown in the figures below. Figure (a) illustrates the dimensions of the axis-symmetric moving coil actuator that are needed in the permeance model. Figure (b) shows partitioning into flux tubes and the permanent magnetic field without current. G_ma and G_mb both are the permeances resulting from a series connection of the permanent magnet and air gap sections. The field plot of the coil-imposed mmf is shown in figure (c) without the permanent magnetic mmf (H_cB=0). The placement of the magnetic network components in figure (d) retains the geometric structure of the actuator. In figure (e), the permeance model is restructured and thus simplified.

Parameters (13)

N Value: 140 Type: Real Description: Number of turns Value: 2.86 Type: Resistance (Ω) Description: Coil resistance Value: 12.5e-3 Type: Radius (m) Description: Radius of ferromagnetic stator core Value: 3.5e-3 Type: Length (m) Description: Radial thickness of permanent magnet ring Value: 0.02 Type: Length (m) Description: Axial length of permanent magnet ring and air gap respectively Value: 3e-3 Type: Length (m) Description: Total radial length of armature air gap Value: 4e-3 Type: Length (m) Description: Radial thickness of outer back iron (for estimation of leakage permeance) Value: Material.HardMagnetic.BaseData() Type: BaseData Description: Ferromagnetic material characteristics Value: 0.012 Type: Mass (kg) Description: Mass of armature Value: 1e11 Type: TranslationalSpringConstant (N/m) Description: Spring stiffness between impact partners Value: 400 Type: TranslationalDampingConstant (N⋅s/m) Description: Damping coefficient between impact partners Value: -4e-3 Type: Position (m) Description: Position of stopper at minimum armature position Value: 4e-3 Type: Position (m) Description: Position of stopper at maximum armature position

Connectors (3)

p Type: PositivePin Description: Electrical connector Type: NegativePin Description: Electrical connector Type: Flange_b Description: Flange of component

Components (10)

material Type: BaseData Description: Ferromagnetic material characteristics Description: Permanent magnet's magnetomotive force Description: Inertia of moving coil + coil carrier; stoppers at end of stroke range Type: Resistor Description: Ideal linear electrical resistor Type: Ground Description: Zero magnetic potential Description: Ideal electromagnetic energy conversion Description: Hollow cylinder with radial flux; constant permeability Description: Hollow cylinder with radial flux; constant permeability Description: Leakage between coaxial end planes of ferromagnetic stator core and outer back iron Type: HalfCylinder Description: Leakage between edges of ferromagnetic stator core and outer back iron

Used in Examples (3)

 ForceCurrentBehaviour Modelica.Magnetic.FluxTubes.Examples.MovingCoilActuator Comparison of the force-current characteristics of both converter models with armature blocked at mid-position ForceStrokeBehaviour Modelica.Magnetic.FluxTubes.Examples.MovingCoilActuator Force-stroke characteristic of the permeance model at constant current ArmatureStroke Modelica.Magnetic.FluxTubes.Examples.MovingCoilActuator Armature stroke of both moving coil actuator models after a voltage step at time t=0