## 4 Verification of Design Method Using a Small-Scaled MG-PMSM Prototype  
### Derivation of the Design Model for 4.5 kW-Class Small-Scaled MG-PMSM  
In order to accurately verify the validity of the 45 kW-class MG-PMSM design method presented in this research, the MG-PMSM prototype with the 45 kW-class capacity must be applied. However, the cost and test-bed conditions are not satisfied to evaluate the performance of the MG-PMSM prototype with a 45 kW-class capacity. Therefore, a 1/10 scale-down prototype was produced considering the available budget and test bed conditions in this research. First, a design model of a 4.5 kW-class small-scaled MG-PMSM was derived by applying the design method suggested in this research. The design requirements of the 4.5 kW-class small-scaled MG-PMSM are 200.4 Nm and 71.8 Nm, respectively, at rated speed and maximum speed, and the Back-EMF voltage limit is 433 Vpeak, and the efficiency is over 92%. Table 7 shows the derivation results of the final design model of the 4.5 kW-class small-scaled MG-PMSM prototype. As shown in Table 7, it can be confirmed that the electromagnetic characteristics of the derived design model satisfy the design requirements. Figure 13 shows the performance characteristics of the final design model. As shown in Figure 13, the Back-EMF of the final designed model does not exceed the voltage limit under the full-load condition, and the torque characteristics also satisfy the design requirements. Figure 12: Performance characteristics of the final design model: (**a**) Back-EMF and rated torque characteristics; (**b**) Torque and efficiency map. Verification of Design Method through Performance Test of the 4.5 kW-Class Small-Scaled MG-PMSM Prototype  
The 4.5 kW-class small-scaled MG-PMSM prototype with concentrated winding is manufactured to verify the validity of the MG-PMSM design method in this research. Figure 14 shows the arrangement of the parts for the assembly of a 4.5 kW-class small-scaled MG-PMSM and assembled prototype. As shown in Figure 14, the outer rotor (pole pieces rotor) of the MG-PMSM prototype is composed of pole pieces and epoxy resin. The pole pieces rotor is made of a laminated silicon steel sheet to reduce the eddy current loss, and the slots between the pole pieces are filled with epoxy resin to secure the rigidity of the rotor. Figure 15 shows a setup of dual load performance tester and peripheral devices for measuring the driving characteristics of the 4.5 kW-class MG-PMSM prototype ((a) Schematic block diagram related to measurement setup; (b) Measurement set). As shown in Figure 15a, two servo motors are applied to the dual load performance tester. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Design Model and Magnetic Flux Density Distribution** & **Contents** & **Value** \\ \cline{2-3}  & Outer Dia. of stator & 260 mm \\ \cline{2-3}  & Stack length of stator & 210 mm \\ \cline{2-3}  & \(\tt{\delta}\) [tes1a] & \(\tt{\delta}\) [tes1a] \\ \cline{2-3}  & \(\tt{\delta}\) [tes1a] & \  
In this research, the validation of the design method and parameters were verified through the no-load and load performance test of the 4.5 kW-class small-scaled MG-PMSM prototype. Figure 16 shows the measurement and calculation wave comparison of the no-load phase Back-EMF of the 4.5 kW-class MG-PMSM prototype. Under this no-load condition, the Back-EMF is measured using the dual servo motor of the performance tester  
Figure 14: Parts arrangement for assembly of 4.5 kW-class MG-PMSM and assembled prototype. Figure 15: Setup of dual load performance tester and peripheral devices for measuring the driving characteristics of 4.5 kW-class MG-PMSM prototype. (**a**) Schematic block diagram related to measurement setup; (**b**) Measurement set. while the pole piece rotor and PM rotor rotate at 214 rpm and 155 rpm, respectively. Table 8 shows the comparison results between the calculated value and measured value of no-load Back-EMF at the rated speed (pole piece/PM rotor@214/155 rpm).