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.

In this paper is used Finite Element Method-FEM for analysis of electromagnetic quantities of small micro motor - single phase shaded pole motor-SPSPM. FEM is widely used numerical method for solving nonlinear partial differential equations with variable coefficients. For that purpose motor model is developed with exact geometry and material's characteristics. Two different approaches are applied in FEM analysis of electromagnetic phenomena inside the motor: magneto-static where all electromagnetic quantities are analysed in exact moment of time meaning frequency f=0 Hz and time-harmonic magnetic approach where the magnetic field inside the machine is time varying, meaning frequency f=50 Hz. Obtained results are presented and compared with available analytical results.