Marco Hombitzer

Study and comparison of several permanent-magnet excited rotor types regarding their applicability in electric vehicles

Due to the limited available space and the high demands in power density and overall efficiency, the permanent magnet synchronous machine (PMSM) is the mainly applied machine type in parallel hybrid electric vehicles (HEV). This machine is used as well in many full electric vehicles (EV). In this work, several permanent-magnet excited rotor types are studied regarding their applicability in EVs and HEVs, and are compared in terms of among others: their maximum torque and power, power density, their efficiency map, field-weakening capability, overload capacity and torque ripple.

Iron-Loss Model With Consideration of Minor Loops Applied to FE-Simulations of Electrical Machines

The accurate prediction of iron losses in soft magnetic materials for various frequencies and magnetic flux densities is eminent for an enhanced design of electrical machines in automotive applications. For this purpose different phenomenological iron-loss models have been proposed describing the loss generating effects. Most of these suffer from poor accuracy for high frequencies as well as high values of magnetic flux densities. This paper presents an advanced iron-loss formula, the IEM-Formula, which resolves the limitation of the common iron-loss models by introducing a high order term of the magnetic flux density. Furthermore the IEM-Formula is extended in order to include the influence of higher harmonics as well as minor loops. In line with this a detailed study of minor loop loss behavior is presented. Exemplarily, the iron-loss formula is utilized to calculate the iron losses of a permanent magnet synchronous machine for the drive train of a full electric vehicle.

Permanent magnet synchronous reluctance machine - bridge design for two-layer applications

The permanent magnet synchronous reluctance machine (PMSynRM) is a combination of the characteristics of two machine types: High efficiency, high power density of the permanent magnet synchronous machine (PMSM) as well as better high-speed performance and lower costs of the synchronous reluctance machine (SynRM). This paper presents a general approach for the electro-magnetic design of a PMSynRM. Essential design rules for constructing a PMSynRM are shown. In particular the rotor configuration is improved by dimensioning of the bridges between flux barriers and air gap. An interior permanent magnet synchronous machine (IPMSM) with two layers which form the flux barriers in the rotor is used as reference. The results are concluded in an objective function.

Influence of Winding Scheme on the Iron-Loss Distribution in Permanent Magnet Synchronous Machines

The influence of the winding scheme [concentrated, single-tooth, distributed (pitched, unpitched)] on the iron-loss distribution in a rotor and stator is to a large extent unknown. At present, windings are primarily selected with respect to back-EMF harmonics and torque fluctuation. In such approaches, the influence of iron losses is disregarded. Moreover, minor loop losses are not covered by most iron-loss models and are therefore ignored. This yields inaccurate results. In particular, for interior permanent magnet machines, the rotor temperature has to be taken into account. For variable-speed drives, losses have to be calculated over the complete operating range. Hence their distribution is studied in this paper for various operating points. The influence of the winding scheme on iron losses and iron-loss distribution is investigated based on finite-element simulations.

Performance improvement of a high-speed permanent magnet excited synchronous machine by flux-barrier design

Due to their high power density and high overall efficiency permanent magnet excited synchronous machines are beneficial to be applied in traction drives of full electric or hybrid-electric vehicles with limited installation space. To improve the performance, additional flux-barriers can be inserted to the rotor of the machine. In this paper, the effects of different flux-barrier positions and sizes are systematically studied. Command variables for the improvement are average torque, torque ripple, total harmonic distortion of the back-emf, iron losses and efficiency.

Cost-oriented design of high speed low power interior permanent magnet synchronous machines

In this paper, the characteristic of interior permanent magnet synchronous machine (IPMSM) with concentrated windings is evaluated for three different rotor geometries. The reference machine is a fractional horsepower IPMSM with single-layer magnets (1-layered IPMSM). The maximum output power of the machine is 820 W. Based on the electrical properties and machine cost of the reference machine, IPMSM with two different rotor geometries are designed. The first one is an IPMSM with v-shaped magnets (VPMSM) and the second is an IPMSM with double-layer magnets topology (2-layered IPMSM). The machines are compared in two operating points: one in the base speed area and one in the field weakening range. The focus of the machine comparison are the parasitic effects due to the non-sinusoidal rotor field, e.g. back-emf harmonics, torque harmonics, radial force densities and iron losses.

Influence of production uncertainties and operational conditions on torque characteristic of an induction machine

The influence of production uncertainties in torque characteristics is evaluated by off line and extensive test bench measurements of ten induction machines from series production. Adapting a machine model to each of the individual machines allows to analyze the deviation of the test bench results.

Improved rotor pole geometry of a PMSM for wind turbine applications with multiple high-speed generators

Wind turbines (WTs) are energy conversion systems with a very complex electromechanical structure, consisting of highly interconnected subsystems, which are constantly exposed to dynamic electrical and mechanical stress. In order to improve their technical and economic efficiency, new alternative drive train concepts are being sought. This paper proposes a WT drive train with multiple high-speed generators. Different electrical machines are investigated analytically and the permanent magnet synchronous machine with V-shaped internal magnets (VI-PMSM) is chosen as the most suited topology for this application. A simple MATLAB Simulink model is developed to validate the proposed WT configuration in terms of efficiency gain. Furthermore, the operational behavior of the VI-PMSM is improved by means of sinusoidal rotor field poles.

Multiphysical design methodology of a high-speed induction motor for a kinematic-electric powertrain

This paper describes a multiphysical methodology developed to design a high-speed induction motor for a technically complicated kinematic-electric powertrain. The main focus lies on the definition of realistic load cycles and the possibility to rapidly refine the motor design and the operating strategy of the powertrain based on results from thermal, structural and vehicle simulations.