1,721,136 research outputs found
Synchronous machines
No full textThis article describes the fundamentals of electrically-excited rotating synchronous machines, either used as motors and generators. Firstly, the main fields of use for these machines are reviewed and their peculiarities are highlighted for the different areas of application. Then, some construction details are explained covering the most common types of synchronous motors and generators. Finally, the operation of these machines is explained in terms of basic calculations and characteristics
Modeling and Analysis of Synchronous Reluctance Machines with Circular Flux Barriers through Conformal Mapping
Full text linkSynchronous Reluctance Machines (SRM’s) are gaining more and more importance in various fields of application thanks to their known merits like rugged construction, high efficiency, absence of field windings, no or reduced need for permanent magnets. Out of the possible design variants, in this paper SynRel motors with uniform mechanical air-gap and circularly-shaped flux barriers are taken into account and a conformal-mapping approach to their analytical modeling and simulation is proposed. A suitable conformal transformation is introduced to compute the reluctance of each rotor circularly-shaped flux barrier and the result is then used to analytically determine the air-gap flux density distribution and the electromagnetic torque of the machine in arbitrary operating conditions. The accuracy of the methodology proposed is assessed against finite element analysis
Leakage Field Analytical Computation in Semiclosed Slots of Unsaturated Electric Machines
No full textSlot leakage field accounts for an important quota of the total leakage flux in electric machines. The computation of unsaturated slot leakage inductances can rely on analytical formulas for simple open slot shapes, while the case of semiclosed slots is more critical and typically requires finite element analysis (FEA) or analytically solving the field over the whole machine domain. This paper sets forth an analytical procedure for computing the leakage field in semiclosed slots of unsaturated electric machines. The method is based on solving Maxwell's equations in the slot domain alone, which is made possible by appropriately defining boundary conditions in the slot opening region. The method proposed is assessed by comparison with FEA. Validations indicate that a good accuracy is achieved by the presented approach in predicting unsaturated leakage inductances, while FEA is required when magnetic saturation effects need to be taken into account
Analytical Determination of Slot Leakage Field and Inductances of Electric Machines With Double-Layer Windings and Semiclosed Slots
Full text linkSlot leakage field and inductance computation are, in general, nontrivial tasks in the analysis of electric machines equipped with semiclosed slots, even under the hypothesis of neglecting magnetic saturation. This paper proposes an analytical method to evaluate the slot leakage field and inductances in dual-layer distributed winding machines, extending the results of a previous work where the single-layer winding design was addressed. A direct solution to Poisson’s differential equation in the slot domain is found by suitably defining boundary conditions in the slot
opening area. Boundary conditions are defined exploiting the analytical form taken by the magnetic field in the neighborhood of ferromagnetic corner-shaped regions. The presented approach is successfully validated against finite element simulations
Accurate computation of multiphase synchronous machine inductances based on winding function theory
No full textAn electric machine equipped with n stator phases is characterized by a set of n × n phase inductances as concerns the stator section. In the case of nonuniform air gap, these inductances vary as the rotor moves. For their numerical determination as
functions of the rotor position an accurate computation algorithm is proposed in this paper based on winding function theory. For
permeance function identification, a numerically efficient method is employed based on the magnetostatic finite-element analysis of
only three appropriately simplified machine models. In the presence of a field circuit, computation of mutual inductances among
it and stator phases is also covered with the same approach. An extension of the method to permanent-magnet machines is also
presented. Results are assessed on a six-phase synchronous generator prototype equipped with either a salient-pole wound-field
rotor or with an interior permanent-magnet rotor
Automazione e ottimizzazione multi-obiettivo nel progetto elettromagnetico delle macchine elettriche
No full textA numeric simulation approach to field protection design in wound-rotor brushless synchronous machines
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