Mats Leijon

• Professor (Full) at Uppsala University

This paper describes a simplified one-phase equivalent circuit model of three-phase salient pole synchronous machines and synchronous reluctance machines. The model represents the pole saliency as a susceptance, with a magnitude based on the pole saliency and a phase angle based on twice the load angle. The reluctance torque itself is then modeled...

There are several models for magnetic hysteresis. Their key purposes are to model magnetization curves with a history dependence to achieve hysteresis cycles without a frequency dependence. There are different approaches to handling history dependence. The two main categories are Duhem-type models and Preisach-type models. Duhem models handle it vi...

This paper studies the properties of the Preisach model and the play model, and compare their similarities. Both are history-dependent hysteresis models that are used to model magnetic hysteresis. They are described as discrete sums of simple hysteresis operators but can easily be reformulated as integral equations of continuous distribution functi...

This paper shows how to model the force density in electrical machines based on the field lines of the magnetic flux density. The force density is written as two vector components: the magnetic tension force and the magnetic pressure gradient force. This approach has been applied in physics but never to forces in engineering problems. The magnetic...

This paper serves as an overview of existing models of permanent magnets for electrical machines. The review study starts with the linear recoil model, which is commonly used to describe the reversible part of the demagnetizing curve. It is a simple model, especially useful for representing materials with high anisotropy, such as ferrite, NdFeB, an...

Hybrid excitation is a technology that combines the advantages of field windings and permanent magnets for inducing magnetic flux. This article studies the benefits of hybrid excitation and provides an outlook on their possible applications, such as wind power generators and electric vehicle motors. Compared to permanent magnet-based machines, hybr...

This paper will analyze how the energy flux of Poynting’s vector is compared to the power flow in electrical engineering, where the power, instead, is defined by voltages and currents. There are alternatives to Poynting’s energy flux vector that agree more with circuit theory methods such that the energy flow is in the current conductor and not in...

Different types of linear generators are simulated and their power flow in the air gap is investigated. The results are compared to the analytical expressions derived in Part 1. The simulations and the analytical expressions in Part 1 show the same general behaviour, but the magnitudes are lower for the analytical expressions. One explanation for t...

Abstract Analytical solutions and estimations for the power flow in the air gap of linear electrical machines of different geometries are derived from Poynting's theorem. The different geometries considered are flat one‐sided, multi‐sided, and tubular linear electrical machines. The radial power flow for all considered geometries is dependent on th...

For many years now, models for representing reality have played a decisive role in the development of control systems. By appropriate abstraction they help to design an efficient development process. Especially in the development of Advanced Driver Assistance Systems (ADAS) a valid virtual development environment is crucial for functionality and re...

Recently, virtual realities and simulations play important roles in the development of urban traffic infrastructure. By an appropriate abstraction, they help to design, investigate and communicate inner-city development processes. Especially, to investigate interactions between infrastructure and future mobility participants, a valid virtual model...