Multiphysics modelling speeds electrical design

Edited by the Engineeringtalk editorial team Oct 24, 2006

The AC/DC module for Comsol Multiphysics accelerates the design and prototyping of devices such as motors, magnets, transformers, power lines and energy-conversion systems.

At low frequencies or even in DC applications, many multiphysics effects come into play in industrial electrical and magnetic devices.

The AC/DC module for Comsol Multiphysics accelerates the design and prototyping of devices such as motors, magnets, transformers, power lines and energy-conversion systems.

Users can select better materials and also help a device or component reach an optimal value of a desired circuit parameter with minimum cost, time, size, and peak performance.

Engineers can configure better layouts and cooling systems, perform failure analysis, and otherwise explore multiphysics aspects such as electrical and heat losses that make such models closely mirror the real world.

In more detail, the AC/DC module handles general static and quasistatic electromagnetics for 2D, 2D axialsymmetric and full 3D geometries.

It supports time-harmonic, transient, and static analysis.

Users can conduct virtually any type of simulation.

For instance, it allows couplings to many physics other than electromagnetics including acoustics or structural mechanics such as to analyse rotating machinery or determine the frequency response of a loudspeaker.

Next, it is extremely flexible in allowing users to couple any arbitrary physics as well as define material properties in a unique, convenient fashion.

In fact, the module comes with two ready-made multiphysics couplings for rotating machinery and inductive heating.

In each case users set up the model with a few mouse clicks.

The module's feature highlights start with support for sliding meshes and torque computations, which are very useful in rotating machinery.

With infinite elements, the software allows engineers to define a field at infinity even while truncating a model's domain to allow for the simulation of larger devices.

The use of higher-order vector elements improves solution accuracy through more efficient solver settings.

Finally, the product takes advantage of state-of-the-art solvers in Comsol Multiphysics to reduce memory requirements by as much as an order of magnitude for some types of problems.

A major application area for the software is in device characterisation and parameterisation for electrical-circuit simulators such as Spice.

The module automatically extracts the values of lumped parameters such as finding the value of a fixed resistor.

However, the software goes much further in that users can, for the case of a resistor, perform a temperature sweep and use these data to extract a Spice model that makes the circuit's operation temperature dependent.

On the other hand, when users have fully specified Spice models for components in a larger system, they can import a corresponding Spice netlist into a Comsol Multiphysics model for simulation of the entire system.

In this way some ideal circuit components as determined by Spice interact with a fully developed multiphysics model of a crucial circuit element, one that accounts for operational changes due to heat or structural effects.

This collection of features makes the module attractive for a wide variety of application areas including the development and analysis of models for sensors, transducers, and actuators; motors and generators; printed-circuit board simulations; transformers; magnets; inductive heating; passive electrical component design and characterisation; shielding for electromagnetic protection, compatibility and compliance; high-voltage power distribution; insulation evaluation; near-field modelling such as for RFID systems; and electrical imaging such as with electrical impedance tomography.

To help users learn how to apply the AC/DC module to these and other application areas, the software comes with a model library with more than 25 real-world examples.

One typical example illustrates the induction heating in a hot-wall furnace for semiconductor fabrication.

Each model has a detailed technical description of the underlying physics along with step-by-step instructions on how to create the model.

In this way users not only leverage the knowledge of Comsol's engineering staff to learn how apply the software to a particular application, they can also load these models and thus gain a valuable head-start in their modelling work.