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The most widely used design scheme of synchronous machines with radially magnetized permanent magnets and a nonmagnetic magnet holder is considered. To calculate the armature reaction inductive reactances in these machines, it is proposed to use the conventional approach and the expressions obtained on its basis for the armature reaction inductive reactances of synchronous machines with electromagnetic excitation. The features of permanent magnet machines can be taken into account by special calculated coefficients included in these expressions. On the basis of the magnetic field analytical solution of the armature reaction, the special calculated coefficient for the design scheme with a cylindrical yoke of the inductor was determined taking into account the increased nonmagnetic gap between the armature magnetic core and inductor yoke core. By applying the Schwartz method with the use of a scalar magnetic potential, a new magnetic field analytical solution of the armature reaction with a polyhedral yoke of the inductor is obtained. On the basis of this solution, the field form factors of the longitudinal and transverse armature reaction were determined, which take into account the real geometry of this design scheme. Graphical dependences of the special calculated coefficients on the active zone geometric parameters are given.

The article addresses a comprehensive study of the quality indicators of the voltage produced by an aircraft synchronous generator. The study is carried out by applying a finite element analysis performed using the ANSYS Maxwell software package taking as an example the three-phase 115/200 V AC aircraft power supply system with a constant frequency of 400 Hz. To check the possibility of applying a finite element analysis, an analytical calculation of an aircraft synchronous generator was performed; its model was constructed in the ANSYS Maxwell software package environment, and the generator operation was simulated in its idle running mode and under the conditions of its balanced and unbalanced load. A finite element analysis of the model with an external electrical circuit connected to it is carried out. The construction and connection of electrical circuits makes it possible to implement the generator operation in different modes for obtaining the output phase voltage waveforms. Based on the simulation results, the electric power quality indicators (the amplitude coefficient, voltage modulation, voltage imbalance, phase voltage shift, distortion coefficient and harmonic components) have been estimated in the steady-state mode for their compliance with the normative values specified by the State Standard GOST R 54073-2017. By using the proposed method, it is possible to estimate the generated voltage quality indicators at the stage of developing an electromechanical converter, which will help reduce the time and cost of electrical machine design process.

The model coil with the racetrack geometry based on second generation High Temperature Superconducting tapes has been developed for an electrical machine where a winding pack is a stack of 2G HTS tapes. It is important to evaluate transport current AC losses and possible methods to reduce them in a winding. In a device made of 2G HTS tapes, the main the AC losses are the hysteresis ones. Only numerical simulation permits to predict them in full. The FEM model for calculation of the hysteresis losses developed before for 2G HTS power cables was modified for a stack of the 2G HTS tapes in a coil. In this paper the methods to increase a computational speed are presented. Possible ways to reduce AC losses are discussed also. The details of the model and comparisons of calculations with measurements of the AC loss are presented.

Construction of electrical machines with increased specific and volume power capacity is a complicated scientific and technical problem, which is dealt with in many papers published both in Russia and abroad. Publications that consider fully superconducting electrical machines, i.e., machines the stator and rotor windings of which are made of superconductors, are the most interesting ones. Among these publications, it is possible to specially separate those on constructing so-called ironless machines with the axial flux and cooled by liquid hydrogen. In using high-temperature superconducting (HTSC) tapes in the composition of electrical machine windings, a few essential limitations must be borne in mind. One of the design arrangements that can be adapted to the use of HTSC windings on the stator is the one with an annular armature winding. The article presents correlations for the inductive parameters of the windings and linear current density of an electrical machine with an annular HTSC winding on the stator. By using the obtained correlations, it is possible to select the rational type of the shield and determine its dimensions and mass. The results from comparing the parameters of two machines in using different types of magnetic shields are also presented.

The use of windings on the basis of high-temperature superconductivity (HTSC) in electrical machines makes it possible to make the machines more efficient due to an essentially higher permissible current load and to make them more compact and lighter, which opens the possibility of constructing fundamentally new systems. However, the operation of HTSC windings with alternating current has not been fully investigated as yet. In particular, the critical parameters of an HTSC coil and a short HTSC sample differ essentially from each other. In addition, during operation of the devices with alternating current, losses occur in them and, in particular, in the superconductor, the correct characteristics of which are necessary for designing the cryogenic system. The article describes the technological process of producing a racetrack type coil made of so-called second-generation (2G) HTSC tape and presents the results of its tests carried out at the liquid nitrogen temperature and with different values of the power supply voltage. Based on the obtained experimental data, the losses in the HTSC coil operating with alternating current have been determined. The obtained study results were used in designing the electric motor for an unmanned aerial vehicle.

Electrical machines in which the superconductivity effect is used can find wide applications owing to the possibility of making them with high specific power capacity, a feature that is of special importance for mobile systems. Works on development of high-temperature superconducting (HTSC) electrical machines with immobile and rotating HTSC windings, unipolar machines, and fully superconducting machines are known [1, 2, 3]. Investigations show that ferromagnetic materials must be used in the machine composition to obtain a high volumetric power value [4]. However, only limited information about fully superconducting machines equipped with ferromagnetic rotor and stator yokes and rotor poles is encountered in the literature. The article considers a salient-pole electrical machine with HTSC windings on the stator and rotor, and with a ferromagnetic core. A procedure for calculating the machine’s main parameters is presented. The procedure involves an approach, according to which the armature winding inductive parameters are determined by solving a field problem with distributed parameters, and the main magnetic flux is determined according to the classical methodology of magnetic circuits. By using this approach, it is possible to take into account the anisotropy of the rotor magnetic properties along the d and q axes, the HTSC tape critical parameters, active zone geometry, and other parameters of the machine.