Overview of the User’s Guide
The AC/DC Module User’s Guide gets you started with modeling using COMSOL Multiphysics. The information in this guide is specific to this module. Instructions how to use COMSOL in general are included with the COMSOL Multiphysics Reference Manual.
As detailed in the section Where Do I Access the Documentation and Application Libraries? this information can also be searched from the COMSOL Multiphysics software Help menu.
Theory for the AC/DC Module
The Theory for the AC/DC Module chapter contains an overview of the theory behind the AC/DC Module. It is intended for readers that want to understand what goes on in the background when using the physics interfaces and — in addition to giving the theory background for each of the physics interfaces — discusses the Fundamentals of Electromagnetics, Electromagnetic Forces, and Electromagnetic Quantities.
Modeling with the AC/DC Module
The Modeling with the AC/DC Module chapter summarizes general procedures and strategies for modeling low-frequencies electromagnetics. Topics include Preparing for Modeling, Modeling Coils, Computing Forces and Torques, Computing Losses, Computing Lumped Parameters, Connecting to Electrical Circuits.
Electric Field and Current Interfaces
The Electric Field and Current Interfaces chapter describes the electric field and current interfaces supported by the AC/DC Module:
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The Electrostatics Interface, which simulates electric fields in dielectric materials with a fixed or slowly-varying charge distribution. Preset Stationary, Stationary Source Sweep, Time Dependent, Frequency Domain, Small-Signal Analysis, and Stationary Source Sweep study types are available.
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The Electrostatics, Boundary Elements Interface, which simulates electric fields in dielectric materials with a fixed charge distribution using the boundary element method. Preset Stationary and Stationary Source Sweep study types are available.
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The Electric Currents Interface, which simulates the current in a conductive and capacitive material under the influence of an electric field. Preset Stationary, Stationary Source Sweep, Time Dependent, Frequency Domain, Small-Signal Analysis, and Stationary Source Sweep study types are available.
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The Electric Currents in Shells Interface, computes electric fields, currents, and potential distributions in thin conducting layered shells. It is used under conditions where inductive effects are negligible; that is, when the skin depth is much larger than the size of studied device. Preset Stationary, Time Dependent, and Frequency Domain study types are available.
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The Electric Currents in Layered Shells Interface, which is very similar to The Electric Currents in Shells Interface.
Magnetic Field Interfaces
The Magnetic Field Interfaces chapter describes the magnetic field interfaces supported by the AC/DC Module:
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The Magnetic Fields, No Currents Interface, which handles magnetic fields without currents. When no currents are present, the problem is easier to solve using the magnetic scalar potential. Thus it is the primary choice for modeling permanent magnets. Preset Stationary and Time Dependent study types are available.
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The Magnetic Fields, No Currents, Boundary Elements Interface, which handles magnetic fields without currents using the boundary element method. It can be combined with the Magnetic Fields or Magnetic Fields, No Currents interfaces for easy modeling of open boundary conditions. The preset Stationary study type is available.
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The Magnetic Fields Interface, which computes magnetic fields with source currents by solving the magnetic vector potential. Preset Stationary, Time Dependent, Frequency Domain, Small-Signal Analysis, and Time to Frequency Losses study types are available. This is the recommended primary choice for modeling magnetic fields involving source currents.
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The Magnetic and Electric Fields Interface computes magnetic field and current distributions when the exciting current is driven by an applied voltage. In most cases, using the Magnetic Fields interface with its dedicated modeling features is the preferred choice over using the Magnetic and Electric Fields interface. Preset Stationary, Time Dependent, Frequency Domain study types are available.
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The Magnetic Field Formulation Interface has the equations, boundary conditions, and currents for modeling magnetic fields, solving for the magnetic field components. It is especially suitable for modeling involving nonlinear conductivity effects, for example in superconductors. Preset Stationary, Time Dependent, Frequency Domain, and Small-Signal Analysis study types are available.
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The Magnetic Fields, Currents Only Interface, which handles magnetic fields with currents only. It is especially suitable for computing the lumped matrix of an array of conductors in free space. Preset Stationary and Stationary Source Sweep with Initialization study types are available.
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The Rotating Machinery, Magnetic Interface combines a Magnetic Fields formulation (magnetic vector potential) and Magnetic Fields, No Currents formulation (magnetic scalar potential) with a selection of predefined frames for prescribed rotation or rotational velocity. Most of its features are taken either from the Magnetic Fields or the Magnetic Fields, No Currents interfaces. Preset Stationary and Time Dependent study types are available.
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The Magnetic Machinery, Rotating, Time Periodic Interface uses a magnetic vector potential formulation, but with only the out-of-plane component. By using a time periodic approach, it is possible to simultaneously solve for all of the time frames. Some of its features are taken from the Magnetic Fields interface. Preset Stationary, Frequency Domain, and Time Dependent study types are available.
The Electrical Circuit Interface
The Electrical Circuit Interface chapter describes the physics interface, which has the equations for modeling electrical circuits with or without connections to a distributed fields model, solving for the voltages, currents, and charges associated with the circuit elements. The underlying theory for the physics interface is also included. Preset Stationary, Time Dependent and Frequency Domain study types are available.
Multiphysics Interfaces and Couplings
The Multiphysics Interfaces and Couplings chapter includes a detailed description for the predefined multiphysics interfaces supported by the AC/DC Module, for example, the Induction Heating interface. It also presents an overview of other predefined multiphysics interfaces and the multiphysics coupling features related to the AC/DC Module.