Line-start synchronous motors have attracted researchers’ interest as suitable replacements of asynchronous motors due to their high efficiency, which has been provoked by strict regulations regarding applicable efficiency classes of motors in the EU market. The research becomes even more challenging as it takes into consideration the diverse rotor topologies with different magnet locations for this type of motor. The rotor configuration with an interior asymmetric permanent magnet (PM) array rotor was chosen for analysis and optimization in this paper as this specific configuration is particularly challenging in terms of placing the magnets with adequate dimensions into the existing rotor of the asynchronous motor with a squirrel cage winding, in order simultaneously to obtain good operational characteristics such as high efficiency and power factor, good overloading capability and low material consumption. Therefore, an optometric analysis is performed in order to find the best configuration of the air gap length, magnet thickness, magnet width and number of conductors per slot, along with modifications of the rotor slot. The motor outer dimensions remained unchanged compared with the starting model of the line-start motor derived from the asynchronous motor, which is a product of the company Končar. The optimized model obtained higher efficiency, power factor and overloading capability than the starting model, along with good starting and synchronization capabilities.

Obtaining an optimal motor design is not always a simple task, considering that it involves designing a model with many interrelated parameters, where each modification significantly affects the motor’s performance characteristics. This paper analyses numerous synchronous motor models with embedded magnets of spoke-type, obtained by varying several parameters (magnets and motor length, magnets width, and number of conductors per slot) within defined limits in a software module optimetric analysis. Each combination of these varied parameters results in a different motor model with corresponding performance characteristics. From the obtained models, the best solutions are identified, i.e., combinations of parameters that result in high efficiency while simultaneously minimizing the consumption of magnetic material and reducing cogging torque. The conducted analysis revealed that there is more than one model that can be considered as optimal, especially when considering multiple objectives, such as high efficiency, low magnetic material consumption, reduced dimensions, and low cogging torque. The application of optimetric analysis also enables the execution of a sensitivity analysis, examining the impact of each varied parameter on the corresponding objective function. The presented methodology offers the designer a range of solutions that can be identified as optimal, providing greater flexibility in the construction of appropriate prototypes.

The Pelagonia region, represented by the municipalities of Bitola, Mogila, and Novaci, is the energy core of the Republic of North Macedonia, yet also one of its most polluted areas due to the long standing dependence on the Bitola lignite fired power plant. In the context of the European energy transition and the need for economy wide decarbonization, local communities play a key role in the shift towards sustainable energy sources. This paper presents results from a project based assessment evaluating the potential for installing photovoltaic (PV) systems on public and municipal buildings in Bitola, Mogila, and Novaci. Using PV*SOL premium simulation software, the optimal installed power, expected annual electricity generation, and associated CO₂ emission savings were calculated for each building. The obtained results enable an assessment of the realistic contribution of these systems to reducing coal dependency, while enhancing the energy autonomy of local public institutions such as schools, kindergartens, health centers, and other state facilities. Based on the simulation data, the Center for Climate Change performed the mapping of the analyzed buildings and their PV potential in QGIS Cloud, providing a public and transparent visualization of the results. The study highlights both the technical and social dimensions of the local energy transition and demonstrates that small scale, decentralized PV systems can represent an important first step toward a post coal future for Bitola and the wider Pelagonia region, contributing simultaneously to CO₂ reduction and improved air quality.

A 10-kW switched reluctance motor is investigated with respect to key design parameters, including the number of winding turns, the stator and rotor pole-arc–to–pole-pitch ratios and the machine axial length. The analysis is carried out by systematically varying these four parameters within predefined bounds and identifying the optimal combination that maximises efficiency. The accuracy of the optimised motor model is validated using manufacturer catalogue data. The results illustrate the influence of each design parameter on the motor’s efficiency. Finally, the transient performance is evaluated, emphasising the importance of appropriate motor control strategies, particularly the selection of turn-on and turn-off angles and proper DC-link size to achieve the desired operating behaviour.

Line-start synchronous motors (LSSMs) have emerged as a promising alternative to induction motors in response to increasingly stringent energy-efficiency requirements. However, the salient-pole permanent-magnet rotor topology has been comparatively less studied than other LSSM rotor configurations, particularly with respect to the influence of its design parameters on motor efficiency and dynamic performance. Initially, the effects of the number of rotor bars and the dimensions of the squirrel-cage winding on motor performance are investigated, and the optimal configuration with respect to starting torque and synchronization capability is selected. The chosen design is then subjected to efficiency optimization by varying four design parameters. An optimetric analysis is employed to evaluate numerous parameter combinations under predefined operating conditions, generating a wide range of motor models. The configuration achieving the highest efficiency is subsequently identified and selected. In addition, the optimization with same design parameters is carried out using Genetic Algorithms (GA), confirming the results obtained through the optimetric analysis. The transient responses of speed, torque, and current are subsequently investigated for both the initial and optimized motor model. The analysis provides insight into the effects of the optimization process on motor starting performance, synchronization capability and steady-state operation enabling appropriate conclusions to be drawn.