Magnetic.Examples

Exemplary usage of solenoid models

Magnetic.Examples.EnforcedMovement Magnetic.Examples.PullinStroke Magnetic.Examples.MotionCycleWithLoad

NameDescription
EnforcedMovement Quasistatic calculation of force-stroke-characteristics for the sample solenoid STA 195205-129
PullinStroke Pull-in stroke of the sample solenoid STA 195205-129
MotionCycleWithLoad Pull-in and push-out stroke of a voltage-fed solenoid with mechanical load


Magnetic.Examples.EnforcedMovement Magnetic.Examples.EnforcedMovement

Quasistatic calculation of force-stroke-characteristics for the sample solenoid STA 195205-129

Magnetic.Examples.EnforcedMovement

Information



With this model, the force-stroke characteristic of the sample solenoid is calculated. As is typical for measurements on real actuators, the armature position is enforced while the solenoid current is kept constant. Quasi-static enforced armature movement ensures that the current is nearly constant during simulation: Dynamic effects between the electrical and the magnetic subsystem (coupled by the electro-magnetic converter of the solenoid model) can be neglected.

In the figure below, simulation results are compared with measured data and with results obtained from magneto-static Finite Element Analysis at different armature positions:

Force-stroke charakteristic of the sample solenoid: measurement, FEA and magnetic network model



Modelica definition

model EnforcedMovement 
  "Quasistatic calculation of force-stroke-characteristics for the sample solenoid STA 195205-129" 
  
  extends Modelica.Icons.Example;
  
  Modelica.Mechanics.Translational.Position EnforcedMovement;
  Modelica.Blocks.Sources.Ramp x_set(
    duration=100,
    height=-(8e-3 - 0.25e-3),
    offset=8e-3);
  Modelica.Electrical.Analog.Sources.ConstantVoltage U_supply(V=13.2) 
    "Supply voltage";
  Modelica.Electrical.Analog.Basic.Ground Ground1;
  Magnetic.Solenoid.STA_195205_129 STA_195205_129 "Sample Actuator";
equation 
  connect(x_set.y, EnforcedMovement.s_ref);
  connect(Ground1.p, U_supply.n);
  connect(EnforcedMovement.flange_b, STA_195205_129.ArmatureFlange);
  connect(U_supply.p, STA_195205_129.pin_p);
  connect(STA_195205_129.pin_n, U_supply.n);
end EnforcedMovement;

Magnetic.Examples.PullinStroke Magnetic.Examples.PullinStroke

Pull-in stroke of the sample solenoid STA 195205-129

Magnetic.Examples.PullinStroke

Information



In this model, a voltage step of 13.2VDC at time t=0 is applied to the solenoid (The step height corresponds to a duty cycle of 50% for that particular sample actuator). The armature will be pulled in until it reaches its minimum position at a stopper.

Simulate with the predefined settings for 0,05 s:

Plot versus time:


Watch the characteristic current drop during the pull-in movement. It is due to the increase of the inductance during the stroke (decreasing magnetic reluctance of working air gap, increasing total magnetic flux).

In the figure below, simulation results obtained with the above settings are compared with a measurement:

Comparison of measured and simulated pull-in stroke of the sample solenoid



Modelica definition

model PullinStroke 
  "Pull-in stroke of the sample solenoid STA 195205-129" 
  extends Modelica.Icons.Example;
  Modelica.Electrical.Analog.Basic.Ground Ground;
  Modelica.Electrical.Analog.Sources.StepVoltage U_step(V=13.2);
  Solenoid.STA_195205_129 STA_195205_129(x_arm(start=5e-3));
equation 
  connect(Ground.p, U_step.n);
  connect(U_step.p, STA_195205_129.pin_p);
  connect(U_step.n, STA_195205_129.pin_n);
end PullinStroke;

Magnetic.Examples.MotionCycleWithLoad Magnetic.Examples.MotionCycleWithLoad

Pull-in and push-out stroke of a voltage-fed solenoid with mechanical load

Magnetic.Examples.MotionCycleWithLoad

Information



With this model, one motion cycle (pull-in stroke and pull out stroke) of a voltage-fed solenoid actuator with a mechanical load is simulated. Reluctance forces always act towards a shortening of the working air gap, since the direction of the generated magnetic force is independent on the direction of the current in the coil. In most applications of solenoid actuators, a return spring is used to deliver the energy for the return stroke.

Simulate with the predefined settings for 0.1 s:

Plot versus time:


Modelica definition

model MotionCycleWithLoad 
  "Pull-in and push-out stroke of a voltage-fed solenoid with mechanical load" 
  extends Modelica.Icons.Example;
  Modelica.Electrical.Analog.Basic.Ground Ground;
  Solenoid.STA_195205_129 STA_195205_129(x_arm(start=3e-3), x_max=3e-3);
  Modelica.Electrical.Analog.Sources.PulseVoltage U_pulse(V=13.2, width=5);
  Modelica.Mechanics.Translational.Spring ReturnSpring(c=1000, s_rel0=0);
  Modelica.Mechanics.Translational.Fixed FrameWithSpringPreload(s0=4e-3);
  Modelica.Mechanics.Translational.SlidingMass LoadMass(m=0.01, s(start=
          3e-3)) "Mechanical Load to be moved";
equation 
  connect(U_pulse.p, STA_195205_129.pin_p);
  connect(STA_195205_129.pin_n, U_pulse.n);
  connect(Ground.p, U_pulse.n);
  connect(STA_195205_129.ArmatureFlange, ReturnSpring.flange_a);
  connect(ReturnSpring.flange_b, FrameWithSpringPreload.flange_b);
  connect(LoadMass.flange_a, ReturnSpring.flange_a);
end MotionCycleWithLoad;

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