In this paper, the design and analysis of a 7.5kW 4 poles line-start synchronous reluctance motor (LS-SynRM) are investigated by considering the maximum inertia and power factor. Since the LS-SynRM must operate at synchronous speed, the synchronization capability, determined by the system inertia, is a crucial performance parameter for various industrial applications. Electromagnetic and mechanical transient analysis of a finite element analysis (FEA) are performed to analyze the maximum inertia under the condition of 380V-60Hz voltage. The initial model is designed by considering the maximum inertia. Moreover, the power factor is also important performance index in industrial applications according to IEC 60034-1. Therefore, a bridge design is proposed based on the initial model, and the improved model is designed by considering the efficiency, power factor, and mechanical stress. To improve the efficiency and power factor, the barrier optimal model is designed based on the improved model. Finally, the barrier optimal model of 7.5kW 4 poles LS-SynRM is manufactured, and experiments are performed to verify the steady-state and starting performance. In the steady-state performance, the efficiency and power factor of LS-SynRM are 93.89% (>92.6% IE4) and 78.1 (>78% IEC 60034-1), respectively. It showed about a 1.59%p higher efficiency than that of IM with IE3 efficiency.

In this paper, the design of novel slotless permanent magnet synchronous motor (PMSM) for a collaborative robot was studied considering the manufacture process of winding. The winding manufacture process of novel slotless PMSM was proposed in three steps. First, the two types of coil units were manufactured based on the winding jig to assemble the coil units. Second, the coil unit was manufactured using the injection molding based on the plastic material such as polyphenylene sulfide (PPS). Third, the units of the coil were assembled to form a stator winding. Considering this manufacture process of winding, the slotless motor design was studied for the collaborative robot. For the design and analysis of slotless motor, finite element analysis (FEA) was performed through ANSYS Maxwell. The electromagnetic performance was analyzed according to the pole-slot combination. Considering the space of the collaborative robot, the basic model was designed. Based on the basic model, the electromagnetic performance was analyzed according to the design parameters such as the thickness of magnet and yoke and turns per slot. Considering the torque and current density, the final model was designed. To verify the FEA results, the slotless motor was manufactured and the experiment and FEA results were compared.

In this study, a current vector pattern is analyzed for inter-turn fault (ITF) diagnosis of induction machines (IMs), and an ITF diagnosis algorithm is proposed. When an ITF occurs in IMs, a negative-sequence current is generated due to fault resistance, even though a positive-sequence voltage is applied to IMs. Based on the mathematical model of IMs with an ITF, the current vector patterns in the stationary coordinate frame are analyzed. The superposition of positive- and negative-sequence components results in an elliptical current vector trajectory, and its orientation varies depending on the fault conditions. The co-simulation using finite element analysis and circuit simulation is implemented to analyze the current vector pattern of IMs with an ITF. The ITF diagnosis is proposed based on the current vector pattern. A 12 kW, four-pole, three-phase IM and terminal box, which was used to implement an ITF, is manufactured, and an experiment setup is established to verify the ITF algorithm. The effectiveness of the proposed ITF algorithm is validated through experimental verification of the manufactured IM and terminal box.