Method of Equivalent Currents for the Calculation of Magnetic Fields in Inductors and Magnets with Application to Electronics

Magnetic components are essential in many applications of electronics. Despite a very clear understanding of magnetic phenomena developed from first principles of Electromagnetics and Maxwell's equations, modelling of the magnetic field, flux and force in a particular system can be a very challenging problem. Often, direct calculations are avoided, and a phenomenological model describing magnetic interactions is used instead. There are a number of methods which can be used for the modelling of the magnetic field due to magnetic materials and inductors and which can provide detailed and predictive information on such systems. Multi-physics scientific packages utilising finite-element methods are among the most common tools as they can solve a wide range of different problems and employ universal numerical algorithms. As a trade-off, they are very resource-intensive and have a low speed of execution. As an alternative, one can develop simulation techniques utilising magnetic dipoles or equivalent currents. These methods are less resource-intensive and very fast; however, they also have their limitations. This paper presents a method of equivalent currents developed for the fast calculation of the magnetic field and flux. We show the application of the method to inductors and permanent magnets that have a particular importance in power electronics and electromagnetic kinetic energy harvesting.