MATHEMATICS, SIMULATION AND MODELLING

Hysteresis solver

12 December 2008

Vector Fields

Vector Fields has extended the accuracy of its Opera electromagnetic simulator for electrical machinery applications with a new finite-element hysteresis solver for soft magnetic materials.

The Hysteresis Solver provides designers of motors, generators and other electrical machinery with an accurate means of accounting for losses and predicting performance changes due to hysteresis effects in the specialty electrical steels that are increasingly being used to enhance machine efficiency.

The hysteresis solver is available as part of the general-purpose Opera simulation toolsuite for static and transient electromagnetic design, or in Vector Fields' application-specific tool for motor and generator design - Opera Electrical Machines Environment. Among the product sectors that can be enhanced using the tool are dynamic electrical machinery, such as motors and generators, as well as actuators and transformers.

The new capabilities of Opera are also expected to appeal to the specialist segment of the motor market, which manufactures hysteresis motors and brakes. The lack of commercial finite element based hysteresis simulation tools means that developers of equipment, which relies strongly on hysteretic effects have typically relied on less accurate analytic design techniques. The finite element analysis Opera system with the improved hysteresis solver now offers such companies access to a highly automated design platform that can not only optimise the efficiency of existing designs, but also radically expand the range of design ideas that can easily be explored.

Vector Fields' new Hysteresis Solver is based on actual measured BH (magnetic induction, and applied field) characteristics. The turning points of the B(H) trajectory are used to predict the behaviour of arbitrary minor hysteresis loops, providing a good approximation of true physical behaviour without requiring extensive computation, and additionally making only realistic demands for materials data. The tool is provided with ready-to-use characteristics for some common silicon steel materials. This library can be expanded easily using data from a manufacturer's datasheet, or by real-world measurement using an Epstein Frame (the standardised device for measuring the magnetic properties of electrical steels).

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