Darko Bogatinov

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.

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.