## 3 Detailed Design Study for 45 kW-Class MG-PMSM with Concentrated Winding  
### Design Topology Study for MG-PMSM with Concentrated Winding  
In general, there are two design topologies for determining the number of pole pieces of MG-PMSM. One is the method of applying the number of stator pole pairs and the number of permanent magnet rotor pole pairs, and the other is the number of stator slots and the permanent magnet rotor pole pairs. In this research, model A and model B are derived using two design topologies, respectively, to design the 45 kW-class MG-PMSM with a concentrated winding. Table 4 describes the two design topologies of the MG-PMSM with the concentrated winding applied in this research. As shown in Table 4, topology A uses the pole pairs of the stator, and topology B uses the slot numbers of the stator when deriving the number of pole pieces. Figure 8 shows the 45 kW-class MG-PMSM design models with concentrated winding derived by applying two topologies, respectively. As shown in Figure 8, both models have 12 slots for the stator, but the number of stator poles, pole pieces, and permanent magnet rotor poles is different depending on the applied topology. Figure 9 shows a comparison of the electromagnetic characteristic waveforms of the designed models at rated speed (214 rpm). As shown in Figure 9, in the case of a full load back EMF and cogging torque characteristics, it can be confirmed that Model A is better than Model B. Table 5 shows a comparison of the results of various designs and characteristics of Model A and Model B designed in this study. As shown in Table 5, in terms of torque and efficiency, the characteristics of Model A are better than those of Model B, and in particular, in terms of size, it is possible to make Model A about 45% smaller than Model B. Therefore, in this research, the model designed by topology A is selected as the final model of the 45 kW-class MG-PMSM with a concentrated winding. \begin{table}
\begin{tabular}{c c} \hline
**Contents** & **Value** \\ \hline \hline \begin{tabular}{c} Stator slots/Stator poles/Pole pieces/Rotor poles \\ \end{tabular} & 42/4/9/14 \\ \hline \hline \begin{tabular}{c} Gear ratio 1 (Pole pieces/Stator pole pairs) \\ \end{tabular} & 4.5 \\ \hline \begin{tabular}{c} Gear ratio 2 (Rotor pole pairs/Stator pole pairs) \\ \end{tabular} & 3.5 \\ \hline \begin{tabular}{c} Gear ratio 3 (Pole pieces/Rotor pole pairs) \\ \end{tabular} & 0.643 \\ \hline \begin{tabular}{c} Outer Dia. Of stator/Stack length/Axial length with end turns \\ \end{tabular} & 508/267/480 mm \\ \hline \begin{tabular}{c} DC link voltage/IP\({}_{\text{Phase}}\) @ Rated speed \\ \end{tabular} & 750 V\({}_{\text{dc}}\) /115 A\({}_{\text{rms}}\) \\ \hline \begin{tabular}{c} T\({}_{\text{ave\_rated}}\)/Torque ripple @ Rated speed \\ \end{tabular} & 2096.5 Nm/8.8\% \\ \hline \begin{tabular}{c} T\({}_{\text{ave\_max}}\)./Torque ripple @ Max. speed \\ \end{tabular} & 758.1 Nm/15\% \\ \hline \begin{tabular}{c} THD (No-load/Full-load) @ Rated speed \\ \end{tabular} & 4.1/6.1\% \\ \hline \begin{tabular}{c} R\({}_{\text{Phase}}\) @ 20 \({}^{\circ}\)C/Back-EMF\({}_{\text{Phase-fund}}\) @ Max. speed \\ \end{tabular} & 0.094 \(\Omega\)/249.6 V \\ \hline \
\begin{tabular}{c} Copper loss/Iron loss/Eddy current loss in PM/Efficiency @ Rated speed \\ \end{tabular} & 1,243.3/133.2/64 W/94.6\% \\ \hline
\begin{tabular}{c} Core/Magnet material grade \\ \end{tabular} & 30 PNF1600/NdFeB(38 UH) \\ \hline \end{tabular}
\end{table} 
Table 3: Specifications of 45 kW-class MG-PMSM Design Model with Distributed winding. Figure 8: Design models and magnetic flux density distributions of 45 kW-class MG-PMSM with concentrated winding ((**Left**): Model A, (**Right**): Model B).