This information is part of the Modelica Standard Library maintained by the Modelica Association.
Similar to rotational DC-Motors, the electro-mechanical energy conversion of translatory electrodynamic actuators and generators of moving coil and moving magnet type can be described with the following two converter equations:
F = c * i V_i = c * v
with electrodynamic or Lorentz force F, converter constant c, current i, induced back-emf V_i and armature velocity v. The model is very similar to the well-known behavioural model of a rotational one-phase DC-Machine, except that it is for translatory motion. For a moving coil actuator with a coil inside an air gap with flux density B and a total wire length l inside the magnetic field, the converter constant becomes
c = B * l.
The converter constant c as well as coil resistance R and inductance L are assumed to be known, e.g., from measurements or catalogue data. Hence this model is well-suited for system simulation together with neighbouring subsystems, but not for actuator design, where the motor constant is to be found on base of the magnetic circuit's geometry, material properties and winding data. See PermeanceActuator for a more accurate model of this actuator that is based on a magnetic network. Due to identical connectors, both models can be used in system simulation, e.g. to simulate a stroke as demonstrated in ArmatureStroke.
Type: ElectricalForceConstant (N/A)
Description: Converter constant
Type: Resistance (Ω)
Description: Coil resistance
Type: Inductance (H)
Description: Coil inductance at mid-stroke
Type: Mass (kg)
Description: Armature mass
Type: TranslationalSpringConstant (N/m)
Description: Spring stiffness between impact partners
Type: TranslationalDampingConstant (N·s/m)
Description: Damping coefficient between impact partners
Type: Position (m)
Description: Minimum armature position
Type: Position (m)
Description: Maximum armature position
Comparison of the force-current characteristics of both converter models with armature blocked at mid-position
Armature stroke of both moving coil actuator models after a voltage step at time t=0