modelSimpleSolenoid

Simple network model of a lifting magnet with planar armature end face

Information

Please refer to the Parameters section for a schematic drawing of this axis-symmetric lifting magnet. In the half-section below, the flux tube elements of the actuator's magnetic circuit are superimposed on a field plot obtained with FEA. The magnetomotive force imposed by the coil is modelled as one lumped element. As a result, the radial leakage flux between armature and yoke that occurs especially at large working air gaps can not be considered properly. This leads to a a higher total reluctance and lower inductance respectively compared to FEA for large working air gaps (i.e., armature close to x_max). Please have a look at the comments associated with the individual model components for a short explanation of their purpose in the model.

Field lines and assigned flux tubes of the simple solenoid model

The coupling coefficient c_coupl in the coil is set to 1 in this example, since leakage flux is accounted for explicitly with the flux tube element G_mLeakWork. Although this leakage model is rather simple, it describes the reluctance force due to the leakage field sufficiently, especially at large air gaps. With decreasing air gap length, the influence of the leakage flux on the actuator's net reluctance force decreases due to the increasing influence of the main working air gap G_mAirWork.

During model-based actuator design, the radii and lengths of the flux tube elements (and hence their cross-sectional areas and flux densities) should be assigned with parametric equations so that common design rules are met (e.g., allowed flux density in ferromagnetic parts, allowed current density and required cross-sectional area of winding). For simplicity, those equations are omitted in the example. Instead, the found values are assigned to the model elements directly.

Parameters

TypeNameDefaultDescription
SI.ResistanceR10Armature coil resistance
RealN957Number of turns
SI.Radiusr_yokeIn13.5e-3Inner yoke radius
SI.Lengthl_yoke35e-3Axial yoke length
SI.Lengtht_yokeBot3.5e-3Axial thickness of yoke bottom
SI.Lengthl_pole6.5e-3Axial length of pole
SI.Lengtht_poleBot3.5e-3Axial thickness of bottom at pole side
SI.Lengtht_airPar0.65e-3Radial thickness of parasitic air gap due to slide guiding
Parameters
SI.Radiusr_yokeOut15e-3Outer yoke radius
Material
FluxTubes.Material.SoftMagnetic.BaseDatamaterialMaterial.SoftMagnetic.Steel.Steel_9SMnPb28()Ferromagnetic material characteristics
Armature and stopper
SI.Radiusr_arm5e-3Armature radius = pole radius
SI.Lengthl_arm26e-3Armature length
SI.TranslationalSpringConstantc1e11Spring stiffness between impact partners
SI.TranslationalDampingConstantd400Damping coefficient between impact partners
SI.Positionx_min0.25e-3Stopper at minimum armature position
SI.Positionx_max5e-3Stopper at maximum armature position

Connectors

TypeNameDefaultDescription
Modelica.Electrical.Analog.Interfaces.PositivePinpElectrical connector
Modelica.Electrical.Analog.Interfaces.NegativePinnElectrical connector
Modelica.Mechanics.Translational.Interfaces.Flange_bflangeFlange of component

Components

TypeNameDefaultDescription
SI.PositionxArmature position, alias for flange position (identical with length of working air gap)
FluxTubes.Basic.Groundground
FluxTubes.Basic.ElectroMagneticConvertercoilElectromagnetic converter
Modelica.Electrical.Analog.Basic.ResistorrCoil resistance
FluxTubes.Shapes.FixedShape.HollowCylinderAxialFluxg_mFeYokeSidePermeance of hollow cylindric section of ferromagnetic yoke
FluxTubes.Shapes.FixedShape.HollowCylinderAxialFluxg_mFeArmPermeance of ferromagnetic armature
FluxTubes.Shapes.Force.HollowCylinderAxialFluxg_mAirWorkPermeance of working air gap (between armature and pole end faces)
FluxTubes.Shapes.FixedShape.HollowCylinderRadialFluxg_mFeYokeBotPermeance of bottom side of ferromagnetic yoke
FluxTubes.Shapes.FixedShape.HollowCylinderRadialFluxg_mAirParPermeance of parasitic radial air gap due to slide guiding
FluxTubes.Shapes.FixedShape.HollowCylinderRadialFluxg_mFePoleBotPermeance of bottom side of pole
FluxTubes.Shapes.FixedShape.HollowCylinderAxialFluxg_mFePolePermeance of ferromagnetic pole
FluxTubes.Examples.Utilities.TranslatoryArmatureAndStopperarmatureInertia of armature and stoppers at end of stroke range
FluxTubes.Shapes.Leakage.QuarterCylinderg_mLeak1Leakage permeance between inner edge of yoke bore and armature side face
FluxTubes.Shapes.Leakage.QuarterHollowCylinderg_mLeak2Leakage permeance between inner side of yoke bottom and armature side (r_i = t_airPar)
FluxTubes.Shapes.Force.LeakageAroundPolesg_mLeakWorkPermeance of leakage air gap around working air gap (between armature and pole side faces)