This paper presents the recent achievements and the progress tendencies of the traction system of public urban electric vehicles (UEV) with reference to trolleybuses and tram cars. The current state of the domain is in full compliance to modern achievements of electro mechanics, power electronics and I. T. The development of the traction systems is focused on increasing the control's efficiency, reducing the energy consumption, increasing reliability and travel comfort. The comparative analysis of the traction motors shows a decrease in popularity of the DC motor usage in favor to AC, permanent magnet, increased phase number and switched reluctance motors. The traction electronic converters are developed basing on IGBT technologies with multifunctional digital systems of control, which functions as diagnosis, control of the component elements and fiber wire communication. FOC, DTC and AI methods are used to control the traction motors. The topological structure with individual control of each wheel is the future of the urban electric vehicles.

Asynchronous motors with six and more phases (usually n-three-phase) are increasingly accepted in electric drive systems of road transport, marine and even aeronautical transport. Multiphase machines are credited with multiple advantages such as: less torque ripple, better power distribution per phase, higher efficiency and fault tolerance capability compared to traditional three-phase machines. There are many publications, but few of them are dedicated to the in-depth study of the multiphase motor (m>3) and especially of the magnetic field in its air gap. The purpose of the present paper: the development of the mathematical model of the magnetomotive force in the air gap of the six-phase asynchronous machines, which determines the fundamental properties of the machine, the structure of the magnetic field and the torque developed, the efficiency, the error tolerance. The research is based on analytical studies and the results of suitable experimental measurements. The paper presents the mathematical model for the harmonic analysis of the magnetomotive force in the air gap of six-phase machines with possible variants of windings on the stator. Based on this study, it was demonstrated that only n-three-phase machines with asymmetrically arranged stator windings have the ability to attenuate higher harmonics with a major negative effect on the developed torque, the applicability and efficiency of traditional tools for reducing higher harmonics in the case of six-phase machines was confirmed. The results of measurements carried out on samples of six-phase machines confirm the findings and conclusions formulated in the paper.

This paper focuses on the determination of the characteristics of refusals in low voltage electrical distribution systems. In order to solve this problem, the phenomena of occurrence of refusals in low-voltage electrical distribution systems, conditioned by different influencing factors, processed and mathematically modelled. The main results of the research consist in establishing the static characteristics of the refusals, the mathematical models that determine the occurrence of the cause phenomena and the parameters that characterize the distributions of the refusals, depending on the occurrence per system, depending on the occurrence per season, depending of interruptions duration and the number of affected consumers. The significance of the results obtained consists in solving a number of problems faced by the operating services of electrical distribution systems, concerning the assurance of reliability of operation, providing the possibility of forecasting and preventing the occurrence of the phenomena of occurrence of refusals, which enable the justified planning of prophylactic measures and ensuring the reliability level.

The paper presents a detailed analysis of the external stakeholders' perception regarding the quality of the “Electromechanical Systems Engineering” study program at the Technical University of Moldova. Based on a structured questionnaire applied to experts from industry, research, and education, the study highlights relevant aspects concerning curriculum adequacy, teaching methods, and the relevance of the developed competencies. The results reveal a predominantly positive appreciation of the program, while also emphasizing the need for modernization of practical content and educational resources.

The paper explores the energy efficiency of general-purpose installations, particularly the equipment used in espresso coffee production, and the unique functions of hydraulic systems. By applying eco-design principles and innovative, efficient solutions, the negative impact on the environment can be significantly reduced, transforming citizens into eco-consumers. The study aimed to explore ways to decrease energy consumption in hydraulic systems of standard installations, particularly in heat transfer processes in solids and liquids, which account for up to 97% of energy consumption in such installations. An innovative solution is presented that converts electric energy into heat in liquids using inductive heat transfer. The instant heating inductive boiler, based on inductive heat transfer phenomena, eliminates the convective and conductive heat transfer losses associated with the operation of the boiler with the resistive heating element. The design methodology for dimensioning this type of equipment is provided, and the simulation model for necessary verifications in MatLab Simscape is created. With its practical benefits, the new inductive boiler reduces the preheating period to 7.5 s compared to the 90 s of systems with resistive heating elements, thereby eliminating the need to keep the coffee machine at operating temperatures during breaks and providing a reliable solution for energy efficiency.

The paper focuses on the development of hybrid battery charging systems for autonomous electric passenger vehicles. Aspects of elaboration and design methodology of the battery charging station are approached both from the three-phase electrical network, but also from a photovoltaic plant. A new structure of the battery charging station with power supply from a photovoltaic plant parallel to the public electricity grid was developed. The photovoltaic plant was dimensioned and the amount of electricity produced and consumed at the charging station was estimated. The excess of energy generated by the photovoltaic plant can be injected into the grid or, in offGrid mode, stored in buffer batteries.