Semi-analytical framework for synchronous reluctance motor analysis including finite soft-magnetic material permeability

A semi-analytical framework is presented for the analysis of Synchronous Reluctance Motors. The model is based on a recently refined definition of the Harmonic Modeling Technique for electromagnetic actuators in polar coordinates, and includes the magnetic field solution in the soft-magnetic motor parts. In order to implement the model, a polar representation of the motor geometry is required. Therefore, a method to define the polar geometry representation is proposed and applied to model a benchmark motor topology. The calculation results of the benchmark motor are then validated against FEA predictions acquired for the actual geometry of the motor. This comparison shows that a good agreement is obtained

Comparison of two anisotropic layer models applied to induction motors

A general description of the Anisotropic Layer Theory, derived in the polar coordinate system, and applied to the analysis of squirrel-cage induction motors (IMs), is presented. The theory considers non-conductive layers, layer with predefined current density and layers with induced current density. The electromagnetic field equations are solved by means of Fourier analysis. Further, we propose two different magnetic models for IMs, namely the Direct Rotor Current (DRC) model and the Indirect Rotor Current (IRC) model. The magnetic models are coupled to the single phase equivalent circuit by means of an iterative algorithm, which also accounts for saturation of the main flux path. Finally, motor parameters are given for a benchmark motor and the DRC model and IRC model are validated against Finite Element Analysis predictions. Comparison of the validation results shows that the IRC model is the most promising one

Semi-analytical framework for synchronous reluctance motor analysis including finite soft-magnetic material permeability

A semi-analytical framework is presented for the analysis of Synchronous Reluctance Motors. The model is based on a recently refined definition of the Harmonic Modeling Technique for electromagnetic actuators in polar coordinates, and includes the magnetic field solution in the soft-magnetic motor parts. In order to implement the model, a polar representation of the motor geometry is required. Therefore, a method to define the polar geometry representation is proposed and applied to model a benchmark motor topology. The calculation results of the benchmark motor are then validated against FEA predictions acquired for the actual geometry of the motor. This comparison shows that a good agreement is obtained

Semi-analytical framework for synchronous reluctance motor analysis including finite soft-magnetic material permeability

\u3cp\u3eDue to the increasing demand for high-efficiency electric motors and the maturity of vector-controlled motor drives, the Synchronous Reluctance Motor (SynRM) has received an increasing amount of attention over the past few years. Classically, SynRMs are analysed using analytical models such as presented by Vagati et al.[1]. These models require little computation time and provide the designer with significant insight into the behavior of the machine, which can be very helpful in making initial design choices. For accurate analysis of the motor performance, however, numerical methods such as Finite Element Analysis are often used, although this significantly increases the computation time per design iteration. To limit the number of FEA simulations, a systematic design procedure for SynRMs, based on a combination of analytical models and FEA simulations, was proposed by Moghaddam et al.[2].\u3c/p\u3

Electric circuit coupling of a slotted semi-analytical model for induction motors based on harmonic modeling

The use of empirically determined coefficients to include the effects of leakage and fringing flux is a large drawback of traditional induction motor (IM) models, such as lumped parameter, magnetic equivalent circuit and anisotropic layer models. As an alternative, Finite Element Analysis (FEA) is often used to determine the magnetic field distribution accurately, although at the cost of a much longer computation time. A good alternative to FEA, both in terms of computation time and accuracy, is harmonic modeling. Therefore, in this work, a previously presented magnetic model for slotted IMs based on harmonic modeling, is extended. The main contribution is the implementation of a direct coupling between the magnetic model and the stator and rotor electric circuit models, both for steady-state and time-stepping approximation of the time dependence. Except for end winding leakage flux, no additional empirical coefficients are required to include leakage and fringing flux effects. The results of the models are validated against FEA results and measurements on a prototype. It is shown that good agreement is obtained for torque prediction, whereas the predicted stator current shows some discrepancy. This discrepancy is caused by saturation of the main magnetic flux path and can be accounted for by hybrid coupling to a model that includes the effect of non-linear soft-magnetic material on the main magnetic flux

Calculation of induced rotor current in induction motors using a slotted semi-analytical harmonic model

Recently, strong improvements have been made in the applicability of harmonic modeling techniques for electrical machines with slotted structures. Various implementations for permanent magnet motors and actuators have been investigated and applied in design and optimization tools. For the slotted structure of induction motors (IMs), however, the method has not been investigated very extensively yet. The main reasons for this are the complexity involved with modeling the large number of stator and rotor slots and the issues arising with the calculation of the induced rotor bar currents. In this work, a slotted harmonic model is implemented for a benchmark IM topology and a method to calculate the induced rotor bar current is investigated. The calculation results are validated by comparison to Finite Element simulations. It is shown that a good agreement is obtained for unsaturated operating conditions

Modeling demagnetization effects in permanent magnet synchronous machines

This paper presents a permanent magnet model which takes temperature dependencies and demagnetization effects into account. The proposed model is integrated into a magnetic fundamental wave machine model using the model- ing language Modelica. For different rotor types permanent magnet models are developed. The simulation results of the Modelica are compared with measurement results. Addition- ally, the fundamental wave model is compared to a finite element analysis in order to assess the applicability of the proposed model

Design and optimization tools for high-efficiency three-phase induction motors

An Expert System (ES) for the analysis and design optimization of low-power, three-phase induction motors (IMs) is presented. The ES is based on analytical models, which are carefully selected from literature, and coupled together to calculate motor performance characteristics. These performance characteristics are computed within a few seconds. Also, validation of the ES calculation results against measurements on four test motors shows that the analysis results are reasonably accurate. Additionally, the ES is applied to redesign a case study motor and a prototype of the new design is realized. The theoretical design results are validated against measurement performed on the prototype. This validation shows that the design optimization works, though a more accurate description of the lamination material B(H) characteristic is desirable to improve the accuracy of the ES