Maxwell 3D Transient

Overview Transient solver computes magnetic fields in the time-domain (instantaneously at each time step) Formulation is based on a current vector potential in solid conductors, and a scalar potential over the entire field domain Field equations are strongly coupled with circuit equations to allow voltage sources and/or external driving circuits Quantity solved is the magnetic field (H) and the current density (J) while magnetic flux density (B) is automatically calculated from the H-field Derived quantities are forces, torques, energy, and inductance

Overview (cont.) Non-linear behavior of magnetic materials is considered Permanent magnets are considered Excitations can be sinusoidal or non-sinusoidal including: Currents and current densities in conductors Voltages and currents applied to windings Permanent magnets Two types of conductors can be considered: Solid: eddy currents are considered Stranded: eddy currents are neglected

Boundaries Thin, perfectly insulating sheets between touching conductors. Same as Neumann, except that current cannot cross the boundary. Insulating Notes: No Balloon Boundary available Planes of symmetry in periodic structures where H is oblique to the boundary. The H-field on the slave boundary is forced to match the magnitude and direction (or the negative of the direction) of the H-field on the master boundary. Matching (Master and Slave) Planes of geometric and magnetic symmetry. Field behaves as follows: Odd Symmetry (Flux Tangential) — H is tangential to the boundary; its normal components are zero. Even Symmetry (Flux Normal) — H is normal to the boundary; its tangential components are zero. Symmetry Ordinary field behavior. Initially, object interfaces are natural boundaries; outer boundaries and excluded objects are Neumann boundaries. Natural boundaries — H is continuous across the boundary. Neumann boundaries — H is tangential to the boundary and flux cannot cross it. Default Boundary Conditions (Natural and Neumann) Used to model… H-Field Behavior Boundary Type

Sources The current density in a conductor. Current Density and Current Density Terminal The terminal (sheet object) for a conductor. Current The terminal (sheet object) for a winding. Coil Terminal Type of Excitation Source The terminal (sheet object) for a current density source. Note: In addition, permanent magnets serve as sources of magnetic fields

Overview of Sources Schematic Option

Source Details A DC “current” (solid or stranded) can be assigned to a terminal A “current density” can be assigned to a 3D object while “current density terminal” is assigned to the 2D sheet object inside of that object Coil terminals allow for the most sources including: voltages, currents, external circuits, or sources which vary with time Coil terminals will automatically report flux linkage and induced voltage plots vs. time under Post Process/ Transient Data For a coil terminal, “Model/Winding Setup” must be used to complete the source setup

Winding Setup Use “Model/ Winding Setup to group windings and assign sources To group coil or conductor terminals, select a terminal from the Coil/Conductor list on the left, and choose Group. To ungroup terminals, select a winding group from the Winding list on the right, and choose Ungroup.

Winding Setup (cont.) Select the winding from the Winding list. To assign a source to a winding: Select the winding from the Winding list. Select the type of source you want to assign: Current, Voltage, or External. Select either Strand or Solid. Enter in extra parameters, such as total turns. For a current or voltage source, you can assign a function. If you want to assign a function, do the following: 1) Choose Function to open the Function window 2) Select or define a function and then choose Done 3) Choose Assign. The source information appears in the Winding list next to the winding name. Choose Assign and Exit to complete winding setup

External Circuits Step 1: Step 3: Edit / Edit External Circuit and launch Schematic Capture Step 3: When exiting Schematic editor specify sources to be either: time, position, or speed dependent Step 2: In Schematic editor each winding appears as inductor symbol

Finalizing Source Setup Completed sources appear in list box in left side window

Setup Solution Options The mesh must be manually created for all transient projects, unless the project is copied from a previously solved Magnetostatic or Eddy Current project Set the Stop time and Time Step appropriately for the simulation (~20 timesteps per cycle)

Setup Solution Options (cont.) Choose Save fields time step for post processing a particular timestep later to create plots After solving at least one timestep, a post processing macro can be created. Select this macro by checking Use Macro and specifying the macro. Any quantities that are written using the Append button in the calculator will appear under Solutions > Transient Data as a new .dat plot file

Setup Solution – Motion Setup Choose Set Band to specify the band object Switch the moving and stationary objects by clicking on Switch Moving Objects

Setup Solution – Motion Setup Specify Rotational or Translation motion Set Anchor Point and End Point for motion Set Positive and Negative limits for motion

Setup Solution – Mechanical Setup For constant velocity, uncheck Consider Mechanical Transient For varying velocity check Consider Mechanical Transient and input: Initial Velocity Moment of Inertia Damping Load