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 of Electromagnetics
In the Review of Electromagnetics 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 discusses the Fundamentals of Electromagnetics, Electromagnetic Forces, and Electromagnetic Quantities.
Modeling with the AC/DC Module
In the Modeling with the AC/DC Module chapter, the goal is to familiarize you with the modeling procedure using this particular module. Topics include Preparing for Modeling, Force and Torque Computations, Lumped Parameters, Connecting to Electrical Circuits.
Electric Fields
The Electric Field Interfaces chapter describes these interfaces and includes the underlying theory for each physics interface at the end of the chapter:
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The Electrostatics Interface, which simulates electric fields in dielectric materials with a fixed or slowly-varying charge present. Preset Stationary, Stationary Source Sweep, Time Dependent, Frequency Domain, and Small-Signal Analysis study types are available.
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The Electrostatics, Boundary Elements Interface, which simulates electric fields in dielectric materials with a fixed charge present. 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, and Small-Signal Analysis 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 under conditions where inductive effects are negligible; that is, when the skin depth is much larger than the studied device. Preset Stationary, Time Dependent, Frequency Domain, and Small-Signal Analysis 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 Fields
Magnetic Field Interfaces chapter describes these interfaces and includes the underlying theory for each physics interface at the end of the chapter:
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The Magnetic Fields Interface, which handles problems for magnetic fields with source currents, solving for the magnetic vector potential and, for voltage driven s, the scalar electric potential. Preset Stationary, Time Dependent, Frequency Domain, and Small-Signal Analysis study types are available. This is the recommended primary choice for modeling of magnetic fields involving source currents.
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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. 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, 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, 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 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 and Frequency Domain study types are available.
Electrical Circuit
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 included at the end of the chapter. Preset Stationary, Time Dependent and Frequency Domain study types are available.
Heat Transfer
Heat Transfer Interfaces chapter describes the physics interface, which combines all physics features from the Magnetic Fields interface in the time harmonic formulation with the Heat Transfer interface for modeling of induction and eddy current heating.
Heat transfer through conduction and convection in solids and free media (fluids) is supported by physics interfaces shipped with the basic COMSOL Multiphysics license.
The Heat Transfer Interfaces, The Joule Heating Interface, and Theory for Heat Transfer in the COMSOL Multiphysics Reference Manual.