Search results for: Luis F. A. Pereira
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Journal of Control, Automation and Electrical Systems > 2019 > 30 > 1 > 41-53
The paper proposes a new method to estimate the electrical parameters of three-phase induction machines based only on the voltages and currents of the stator acquired during a no-load startup test. The method is based on the instantaneous impedance and on the rotor speed, both estimated according to procedures detailed in the paper. Parameter variations with the speed are determined based on the concept...
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The distribution of the induction in the airgap of five-phase induction machines operating with an open phase is investigated. Analytical expressions are given in terms of steady-state symmetrical components which are related directly to the airgap induction. It is shown that under fault, third harmonic induction components arise which can potentially produce extra magnetic losses in the stator and...
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In the first part of the paper, a complete model to describe the unbalanced operation of five-phase induction machine is presented. To show the application and validity of this model, in this second part, it is applied to study two typical cases: voltage unbalance and loss of one stator phase. The data used here refer to a five-phase prototype machine of 5.5 kW. Special attention is given to those...
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The unbalanced operation of five-phase induction machines is described using the method of steady state symmetrical components and including aspects not yet considered, such as the changes in the airgap induction. Starting from the dynamic equations, described by instantaneous symmetrical components, sequence equations are obtained in terms of steady state symmetrical components, thus establishing...
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This paper presents a methodology to provide information for decision-making toward the real-time quantification of financial losses in distribution systems. Using multi-criteria analysis and data from an automated measurement system, the proposed method includes the evaluation of main factors that impact on power quality and reliability indexes. Additionally, aspects related to economic issues and...
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This paper proposes a convex approach to the design of robust discrete-time observers to the state estimation of induction machines subject to rotor resistance variation and load disturbance. The observer gain is designed in order to minimize these effects on the state estimation in an ℋ∞ sense, while guaranteeing the error dynamics stability. The pro- posed conditions are cast in terms of state-dependent...
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Journal of Control, Automation and Electrical Systems > 2015 > 26 > 5 > 521-534
The optimization of five-phase induction machines is addressed using a new procedure based on genetic algorithms. A constrained optimization model is introduced which considers the main machine dimensions as free variables. Number of stator and rotor slots, winding pitch, and rotor bar inclination angle are among the free design variables. In addition, the relationship between fundamental and third...
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Journal of Control, Automation and Electrical Systems > 2015 > 26 > 3 > 255-271
In this paper, the main electrical and magnetic parameters of five-phase machines are described in terms of the main dimensions and the winding characteristics. An analytical model is presented that accounts for the effects of saturation and losses; both effects have been neglected in most published works on high-phase machines. The model validation is performed through finite element analysis for...
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The steady state operating curves of three design variants of a five-phase induction machine are assessed and compared to a standard three-phase induction machine of the same size which is taken as the basis for the comparison. The performance in terms of torque, power factor, stator current and efficiency are analyzed for different load conditions. The operating curves are determined by means of...
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Computer aided design tools are nowadays important for a variety of engineering fields. One of the most used tool is MATLAB/Simulink®, which has a broad variety of libraries and is recognized by its reliability. This paper presents a toolbox library for simulation and prototyping of control techniques for three and five phase induction machines, developed in MATLAB/Simulink®and to be used with dSPACE®DS-1104...
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The paper addresses a comparison between the performance of a five phase and a three phase prototype induction machine under steady state. The main aspects included in the comparison are: torque capability, efficiency, power factor, losses and active volume. An analytical model for steady state including losses and saturation is also presented; the model also considers the effect of the third harmonic...
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The paper assesses the torque capability of high phase induction machines taking a conventional three phase machine as the basis for comparison; analytical expressions for torque as a function of phase number for machines with sinusoidal and trapezoidal airgap field are derived and discussed. A trapezoidal field is assumed to be produced through the imposition of a third harmonic current in the stator...
