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.

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The method of genetic algorithms is used to optimize the efficiency factor of two objects: single a phase shaded pole motor and the main inductor for an LCL filter, aimed for independent operation. By varying the construction parameters, three motors and two inductor models have been designed and optimized. The optimized motors exhibited a gradual increase of the efficiency factor achieved for the same input power. Also an increased output power has been achieved, which considerably improved the low efficiency factor for this type of the motor. The optimized filter models have an increased efficiency due to the lower losses and a decreased warm-up. All models are evaluated by the finite element method, which allows to plot the magnetic flux density distribution in the cross section and hereby the possible weak parts of the construction with a high flux density can be discovered.

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