Development of Electrical Machines: Latest Studies and Future Prospects

Dear Colleagues,

This Special Issue aims to record the findings of latest studies and research activities on materials, production processes, design particularities, configuration conception, fault tolerance and measurement techniques regarding the development of high-performance electrical machines. In this regard, papers dealing with the recent research, application and configuration of constitutive parts, design and operation of high-performance electrical machines are welcome.

The main topics of interest include but are not limited to the following:

• Thin iron laminations and low-loss alloy magnetic steels implemented in electrical machine cores.
• Winding configurations and cooling techniques for high-performance electrical machines.
• Multi-phase electrical machines.
• Permanent magnet materials and associated loss reduction techniques.
• Harmonic losses and converter control enabling high efficiency drives.
• Ceramic and electromagnetic bearings for high-speed and high-efficiency machines.
• Machine topologies and design considerations favoring high-performance machines.
• Measurement techniques for high-performance machines.
• Lamination cutting and core building factor loss reduction methods.
• Design of fault-tolerant electrical machines.

Prof. Dr. Antonios G. Kladas
Dr. George J. Tsekouras
Guest Editors

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• high-speed electrical machines
• ceramic and electromagnetic bearings
• electrical machines for renewable energy generation
• electrical machines for electric vehicles
• electrical machines for electric ship and aerospace applications
• permanent magnet electrical machines
• low-loss iron laminations for electrical machines
• advanced cooling techniques in electrical machines
• multi-phase electrical machines
• advanced control techniques for electrical machines
• fault-tolerant electrical machines

Title: Diagnostics of high-power generators on ships in all electrical ship using the Principal Component Analysis (PCA) method
Authors: Nikolaos G. Kintzios 1, George J. Tsekouras 2, Nikolaos M. Manousakis 3, Antonios X. Moronis 4, Antonios G. Kladas 5
Affiliation: 1 PhD Cand, Department of Electrical and Electronic Engineering, UNIWA; 2 Assistant Professor, Department of Electrical and Electronic Engineering, UNIWA; 3 Associate Professor, Department of Electrical and Electronic Engineering, UNIWA; 4 Professor, Department of Electrical and Electronic Engineering, UNIWA; 5 Professor, School of Electrical and Computer Engineering, National Technical University of Athens * Correspondence: [email protected]
Abstract: The recent technological developments in ship propulsion in order to reduce pollutants of gas emissions, in accordance with IMO requirements and to make ship operation more economical, have led to the use of more expensive and alternative but cleaner fuels, combustion optimization and the re-emergence of electro-propulsion systems (EP). A typical coupled electro-propulsion (EP) system consists of an internal combustion engine (diesel or gas turbine), a generator and an azimuth thruster pod drive (AZIPOD). Rarely classical axial system with propeller are used. Before decades, the electro-propulsion (EP) installed and worked as the main propulsion system on several types of ships, although later was limited on special types of ships, e.g. submarines, minesweepers and supporting ships oil rigs etc. Despite its complex structure offers a number of advantages to ships, such as flexibility in engine configuration and operation (constant number of revolutions per minute – RPM) of the coupled internal combustion engines, excellent maneuverability and immediate response to speed requirements. In addition, the installation Azipods abrogates restrictions to the design of the sterns, thus the designers created more efficient hydrodynamically sterns due to the elimination of axial systems, propellers and rudders, etc., resulting of the hull efficiency and hence fuel savings. The complexity treatment of these system is a technological challenge to create innovative diagnostic tools for faults and malfunctions. The scientific approach is useful to be holistic, so that it is possible to export conclusions about the electro-propulsion system either from the processing of thermodynamic data of internal com-bustion engines or from the processing of electrical measurements. In this paper, presents the results from processing and analyzing the winding temperature data from a ship generator at various electrical loads, with the principal component analysis (PCA) method, extracting useful conclusions about the operation of generators. In addition, an asymmetric temperature rise in a phase winding was simulated and interrogate the sensitivity of the method. It was clear the difference between the healthy operation and malfunction. In future applications could be created thresholds for early warning for possible faults. Finally, the need for installation and recording additional measurements such as current per winding, or the pressures and combustion temperatures of the coupled internal combustion engines with the generators is necessary, because the process of these data will reveal useful conclusions about the operation of an electro propulsion.