Combination of Finite Element and Analytical Models in the Optimal Multi-Domain Design of Machines : Application to an Interior Permanent Magnet Starter Generator

Abstract

This paper proposes to apply optimal multiphysic models to the design of highly constrained electrical machines, such as interior permanent magnet machine (IPM) intended for an automotive integrated starter generators (ISG). One of the main problems in the use of such optimal approaches remains the accuracy of the models used by the optimizer. In a previous paper [1], we proposed a design model linked to three strong hypotheses : 1) Iron losses are calculated according to the flux density fundamental (sinusoidal approach) 2) Flux densities are estimated with a saturated but decoupled d,q reluctant circuit model neglecting the cross saturation effect 3) Thermal states are indirectly treated with a current density limit. The present paper improves theses models by using first the finite element method (FEM) for the determination of flux and iron losses in the machine and then an equivalent thermal steady state lumped parameter network. These models are included in the optimization loop and so are evaluated at each iteration. The optimization method uses standard sequential quadratic programming algorithm (SQP) and Sequential Simplex algorithm. A comparison between the design of an IPM machine with the previous model and the new one will be performed.

Conceptual Framework of Antecedents to Trends on Permanent Magnet Synchronous Generators for Wind Energy Conversion System

“…The result from the experiment has proved that rotor core is extremely hotter than expected [40]. Jérome Legranger, et al, (2010) presented in the optimal multi physics design of machines of an Interior Permanent-Magnet Starter Generator with a blend of FE and analytical models. To forecast the stator winding and rotor magnet's temperature, a thermal model may be used which is a 3-D transient lumped-parameter network.…”

“…The archetype has temperature sensors in various key points of the stator machine. The experimental study is based on the measure of three points (i) slot temperature (145°C); (ii) end winding temperature (146°C); (iii) tooth temperature (110°C) [61]. To avoid the excessive cooling requirements, the stator windings' current density is restricted to 3-6 A/mm 2 and the current loading to 40-60 kA/m [77].…”

“…To analyze the performance of the machine, a coupled field and circuit model solved by a time-stepping finiteelement technique is used [53]. Stéphane Brisset, et al, (2008) presented a comparative study of various configurations of an axial-flux nine-phase concentrated-winding PMSG for direct-drive wind turbine [61]. Johannes H.J.…”

Power Electronic Converter Configuration and Control for DC Microgrid Systems

“…In order to assess the machine performance, the researcher used a coupled field and circuit model which was solved using the time-stepping finite-element technique [127]. In 2008 [128], and 2010 [129], conducted a comparison of different configurations in an axial-flux nine-phase concentrated-winding PMSG for a direct-drive wind turbine.…”

Principle of Operation and Performance of a Synchronous Machine Employing a New Harmonic Excitation Scheme

“…Besides permanent magnet poles on the rotor, tooth-harmonic coils were installed on the rotor which generates voltage induced by the inherent tooth harmonic magnetic fields as a result of slots, then after rectification, the tooth-harmonic coils supply DC field current to the excitation windings on the rotor. In all of these research efforts, hybrid excitation machines showed certain attractive performance features, but a wide speed range flux weakening performance was still difficult to achieve [6][7][8].…”