This paper is devoted to the investigation of synchronous generators of double excitation due to high-temperature superconducting (HTS) stationary field winding and permanent magnets in the rotor with claw-shaped poles. The rotor of such generators does not have windings and can work at high rotating velocity. That allows improving the specific weight of the generator. Double excitation increases reliability of the machine if HTS winding quench appears. The latter is very important for vehicle power systems. The design and test results for such generators with output power 21,7 kVA are presented in this paper. The future applications are discussed.

High-temperature superconducting (HTS) bulks can be used in electrical applications. Experimental characterization of large-size HTS bulks is a tricky issue. The relevant parameters for their application were directly measured in this study. This paper has three main aims. Firstly, features of YBaCuO bulks are presented. Secondly, an electrical motor application is developed using magnetic field shielding and trapping. Thirdly, the HTS bulks are characterized. Several classical methods were used, which are mainly magnetic methods only available for small samples. The complete penetration magnetic field and the critical current density were found to be the main parameters relevant for applications. An innovative entire HTS bulk characterization method is presented. This characterization method is useful for end users and engineers to better implement HTS bulks.

Specific power, defined as the ratio of output power to total mass, is one of the generally accepted figures of merit for electrical machines. Given the growing interest in electric aircraft, developers are trying to demonstrate a high value of this indicator for their products. This paper provides an overview of the projects of electrical machines with high power density, the use of which is promising in aircraft of various dimensions. Projects of the University of Nottingham, the University of Illinois, Siemens, Yasa, and others were considered. An analysis of their technical and technological characteristics and approaches to design, manufacturing, and testing is given.

The article is devoted to the study of losses in devices based on high-temperature superconductors of the 2nd generation. The complexity of the devices under study increases from a single rack coil to a winding assembled from several coils, and finally to an electric machine operating in generator mode. This is the way to experimentally study the behavior of 2nd generation high temperature superconductor (2G HTS) carrying a transport current in various conditions: self-field, external DC, and AC magnetic field. Attention is also paid to the losses in the winding during its operation from the inverter, which simulates the operating conditions in the motor mode of a propulsion system.