Lauric Garbuio

Efficient Reluctance Network Formulation for Electrical Machine Design Using Optimization

The aim of this paper is to discuss electrical machines building and computation while taking into account the change of reluctance network (RN) topology required in an optimization process. Indeed, as electrical machine RN changes during an electrical period, this model has to consider several rotor positions to analyze harmonic influence on machine performance (e.g., its torque and losses). Such a requirement can also be important in applications where machine geometry changes shortly during sizing process by optimization. These two cases are addressed in this paper. Using established independent meshes of the initial RN, this paper proposes an algorithm to deal with all topologies necessary for an optimization process. This aims to reduce the computation time, increase the model, and improve the solving stability. An output selectivity approach is also applied on the RN modeling to improve the computation time of the optimization process. The simulation results are compared to finite-element methods and the optimization performance is presented.

Analysis of slot-pole combination of fractional-slots PMSM for embedded applications

During the design of permanent magnet synchronous machines (PMSM), the first step that engineers have to do, concern the choice of the topology, i.e. the slot/pole combination. Given that the performances of the machines are strongly related to this combination, the choice has to be fully justified. Fractional-slots (FS)-PMSM offers several advantages and have been focused by a lot of researches. However, depending on the topology, these machines could have major drawbacks as magnetic noises, high iron and eddy-current losses and low fault-tolerance. The aim of this paper is to give an overview of each machine considering the most common slot/pole combination in order to single out if a topology is suitable or not. A special focus is also done on the homopolar component which traduces the machines fault tolerant capability required for embedded applications.

Synchronous reluctance motor multi-static MEC model

High efficiency, low cost and high reliable electrical machines are designed to meet very demanding specifications for a wide range of applications. The SynchRM (Synchronous Reluctance Motor) has very interesting properties and features. One of the main advantages is that the motor can be designed without rare earth materials permanent magnets. In this article, a modelling method of such machines using the MEC (Magnetic Equivalent Circuit) is proposed. The main challenges are to obtain a very accurate parametric model in order to calculate torque variations and to make possible geometric optimizations in future work.

Computation Code of Software Component for the Design by Optimization of Electromagnetic Devices

This paper deals with the formulation and programing of architecture of software component generated by Reluctool. This software tool allows the modeling of large reluctance networks of electrical machines. Portable model formulation and code architectures are introduced facing the model generation time, the model size, and the computation time. Different approaches are discussed to improve this aspect. Finally, the code architecture is compared with the actual code architecture of the commercial and previous version of Reluctool.

Design & comparison of a conventional and permanent magnet based claw-pole machine for automotive application

This paper presents the design and performance comparison of a conventional claw-pole machine with a permanent magnet based claw-pole machine for automotive application. The magnets are placed in the inter-claw region to decrease the leakage flux and to supply increased magnetic flux in the machine. It has been observed that with the addition of permanent magnets weighing only a few grams, there is a significant increment of more than 22% in output power of the machine. The geometric dimensions of magnets were also varied to verify their effects on performance and it has been observed that with the increase in magnet weight there is a non-linear increment in torque of the machine.

Design and comparison of outer rotor bonded magnets Halbach motor with different topologies

The outer rotor Halbach cylinder motor is designed for hybrid electric vehicle application. The Halbach cylinder is made of bonded magnet and hence the design presented is high torque density motor with low remanence magnet. Different slots poles combinations for double layer tooth coil winding is also evaluated to find the best combination. The Halbach cylinder motor is also compared with different other motor topologies. The outer rotor Halbach motor has the highest torque compared to other topologies over the whole speed range. Variations of inductance and flux linkage of different topologies are also studied and are presented in the article.

Performance analysis of windings configuration on fractional-slots PMSM performance

During the first steps of machines design, engineers have to choose the topology the most appropriate to the specifications. The topology includes the number of stators slots, the number of rotors poles and the winding associated. Traditionally, designers choose one of the common used topology in the industry and consequently, a lot of solutions are not studied. In fact, the performances of the machines are strongly linked to this choice that has to be fully justified. Then, in this paper, a method from the star of slots is presented and also the way to determine the different winding configuration that could exist for each slots/poles combination. An approach to rapidly evaluate the overall performance of Permanent Magnet Synchronous Machines (PMSM) is also used. Thus, designers can perform better choice of the PMSMs topology regarding the specifications.

Effect of static or dynamic eccentricities on the unbalanced magnetic pull in Doubly-Fed Induction Machines

A small eccentricity in a Doubly-Fed Induction Machine can have a huge impact and results in a big Unbalanced Magnetic Pull. This paper presents an analytical method that has been developed to compute the UMP due to a static or a dynamic eccentricity. This method considers saturation in the electrical steel and the damping effect of the circulating currents flowing in the parallel paths of the stator. It has been developed under no load conditions. The last part of this paper will be a comparison between the results obtained analytically and the ones obtained by finite-element computations.

FEA based analysis on effect of slot pole combination on motor torque and magnet eddy current loss with bonded NdFeB Halbach rotor

The effect of slots poles combination on inductance and torque was investigated on the motor with outer rotor bonded NdFeB Halbach cylinder designed for automotive application. Motor with Halbach rotor has better performance with higher number of slots and poles combination. The magnet eddy loss was calculated and analyzed with different slots poles. The impact of rotor back on the eddy current was also investigated. The eddy loss calculated using 3D FEA models were also compared with 2D and shows a big difference between the two.