Magnetic components, Transformers & Chokes

High-frequency transformers and filters are present in all current converters

Chargers for electrical equipment (electric cars, computers, phones), electric motor controllers, renewable energy production (solar panels, wind generators, etc.), and storage (batteries) systems. The size, weight, cost, efficiency, and risk of overheating of power converters depend to a large extent on these components.

Simulation software for magnetic components

Industries that rely on electrical energy converters are constantly looking for new ways to increase efficiency and reduce the size of magnetic components. According to most of our customers, it is becoming increasingly difficult to meet their specifications and offer designs that can meet all their needs. Several simulation packages are commercially available for a similar purpose, but they lack an intuitive user interface, are very expensive, especially for startups, and require a powerful processor to run the software.

Rising material prices are forcing manufacturers to redesign their magnetic components and choose cheaper alternatives, such as replacing copper with aluminum to remain competitive in today’s market.

Temperature distribution in transformer

Calculation of inductance, efficiency, and thermal management are the three most common parameters for numerical optimization of transformers and chokes. Among all, analytic and empirical estimates for high-frequency applications oftentimes underestimate losses and are the most challenging.


The best, most modern way to optimize them is to model numerically allowing engineers to build and test a virtual prototype of a design relatively quickly. With the use of specialized simulation software, we can account for nonhomogeneous and temperature-dependent properties of ferrites and electrical steels, and achieve greater accuracy.

Current trends indicate that researchers and engineers are more inclined to work with open-source software. In particular, we find that Elmer FEM is very versatile and suitable for industry problems.

Current density

Ferrite core loss

Different types of coil windings are represented by massive, stranded, or foil models and can be connected to circuit module with R/L/C components. Time-transient electromagnetic models are used for cases requiring studying full harmonic spectrum in a short time interval while harmonic (or so-called complex) notation provides fast and accurate solutions for a specific frequency.


Hysteresis models and losses are other areas where different numerical methods are used starting from simple complex permeabilities or B-H curves and ending with Zirka’s model for non-sinusoidal fields. Measured B-H data that is typically provided by manufacturers, can be used for transient simulations. For the time-harmonic simulations with small or no gaps, or saturated core, an effective B-H curve has to be derived and used instead.


For high-frequency sinusoidal loads, the electromagnetic part of the problem is solved in a time-harmonic (steady-state) manner while the thermal part of the problem is solved transiently or in a steady-state manner. Electromagnetic fields are periodically recomputed to update temperature-dependent properties of materials and achieve greater accuracy.

Convective heat transfer can be approximated with special boundary conditions and two parameters. Heat transfer coefficient and external air temperature are parameters that are defined on all boundaries representing the interface between air and solids. Alternatively, a more accurate approach is using the coupling capabilities of our software EOF-Library and adding CFD software OpenFOAM for Conjugate Heat Transfer analysis.

We have templates for transformers and chokes in a wide frequency range. Large 3D models (more than 5M elements) can be solved in a reasonable time using fast iterative numerical methods.

SIA EOF Consulting ir noslēdzis 28.02.2020 līgumu Nr. VP-L-2020/12 ar Latvijas Investīciju un Attīstības Aģentūru par atbalsta saņemšanu vaučera programmas ietvaros. Pētījuma mērķis ir veikt eksperimentālo izstrādi, lai atrisinātu 3 industriālu problēmu modeļuzdevumus. EOF Consulting LLC signed contracts BIZIN-I-2019/731 and SKV-L-2019/115 with LIAA for recieving support from ERAF projects ( and

We received a grant from Olaine municipality as part of the Iedvesma competition: