Models for induction machines with magnetic saturation of the main flux path (original) (raw)

Accounting for magnetic saturation in induction machines modelling

International Journal of Modelling, Identification and Control, 2011

A new model is developed for (uniform air-gap) induction motor that accounts for the saturation feature of the machine magnetic circuit. It is built-up starting from the basic electrical/mechanical laws and turns out to be quite different from the standard model that is widely used in control oriented literature. Specifically, the new model involves state-dependent parameters. An experimental validation using a real 7.5 KW machine proved the good accuracy of the proposed model. A simpler control-oriented version of the model is also developed and shown to be quite representative of the machine.

Model of the induction machine including saturation

2013 15th European Conference on Power Electronics and Applications (EPE), 2013

This work proposes a model for induction machines in natural coordinates "abc", developed considering the nonlinear characteristics of saturation. Traditionally, the models for the induction machine including this effect make use of linear transformations. However, the nonlinearity of saturation does not allow the use of these transformations, giving invalid results. Flux linkage in each phase leads to the saturation coefficient and this to the magnetic permeance. Hence, the saturation coefficient produces a new inductance in natural coordinates that considers the nonlinearity of saturation. The machine behavior is computed using a state variable model in natural coordinates described in the space vector frame. The results obtained by the proposed model give a better harmonic representation than the "dq0"models obtained by neglecting the magnetic hysteresis effect. A comparison between the proposed representation and the traditional one shows the advantages of the former.

A novel method for modeling magnetic saturation in the main flux of induction machine

2006

The phenomenon of saturation of electric machines constitutes an important subject of investigation in electrical engineering. This paper presents a new modeling technique for saturation in the case of induction machines. Necessary calculations to introduce this technique in the linear flux model are presented. Computed results and experimental tests on the transients of the self-excited induction generator are clearly compared. These experimental and computed results agree closely, validating the proposed technique as well as the developed model.

Saturated induction machine steady-state performance assessment through simulations

2014 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM), 2014

This paper presents results regarding the influence of the magnetic core saturation on the steady state performances of the induction machine (IM). The assessment is done through simulations performed with an IM model developed with the use of state equations and modified nodal equations. When analyzing the induction motor operating at steady state, we've considered a modified version of the well-known Π (Steinmetz) per-phase equivalent circuit. In the modified circuit, the magnetizing inductance is considered as a current-controlled nonlinear inductor, while the rotor resistor as a time-variable resistor. For simulations we used two software packages: ENCAP (Electrical Nonlinear Circuit Analysis, which is based upon modified nodal equations) and SYSEG (Symbolic State Equation Generation, which is based upon state equations). The state equations can be integrated through an existing routine from MATLAB/Simulink package. The features of the above mentioned programs include the Fourier analysis capabilities, with the direct application to calculating the harmonics of every order present in the current and voltage waveforms. Following the computing of harmonic content, we assessed the steady state characteristics (power factor, efficiency, etc) of the induction motor. I.

A practical approach to modelling induction machine saturation

European Transactions on Electrical Power, 2004

This paper deals with a new approach for saturated induction machines modelling based on the so-called H-G diagram. This allows the description of the saturation in the machine using only three parameters that are instantaneously determined by a plotted circle (H-G diagram) for each saturation point. Furthermore, this approach can be extended to induction machine modelling taking into account other phenomena such as temperature and skin effects. The proposed approach has been compared to the conventional induction machine modelling with and without cross-saturation. Simulation results have shown that the proposed approach has some advantages over cross-saturation such simplicity and accuracy, especially during the induction machine starting-phase and also when it is sufficiently loaded.

Modeling and performance of linear induction motor with saturable primary

1991

This paper presents a 2-D electromagnetic field analysis of the single-sided linear induction motor (LIM), taking into account saturation in both primary and secondary cores. An analytical layer model has been developed in which the primary core is modeled by two Merent layers representing the yoke and teeth-slot regions. Such representation facilitates the evaluation of the magnetic state of the primary yoke and teeth separately. A new generalized mathematical formulation of a multilayer model is presented. The analytical computation results from a seven layer model correlate very well with experimental results obtained from an intermediate-capacity transit system LIM. The developed model is well-suited for sensitivity analysis and design studies.