# FEA-Based Design Procedure for IPMSM and IM for a Hybrid Electric Vehicle
## 5 Simulation Results and Discussion
### Comparison of the Radial-Flux Designs with Axial-Flux Benchmarks  
Given the tight axial length constraint of the traction application considered, axial-flux PM designs are an important alternative to the radial-flux PM and IM designs covered in this paper for this traction application. Thus, the performance parameters of the designed radial-flux machines are compared with four commercially available axial-flux designs and two axial-flux designs described in the literature, as shown in Table 6.  
The radial-flux IPMSM and IM designs use Class F insulation and, with the assumed 80 \({}^{\circ}\)C liquid coolant, are designed for operation at 130 \({}^{\circ}\)C during steady-state operation. The application requirement has a 2800 rpm rated speed. To provide a fair comparison, the output power of the benchmark machines is derated for this cooling arrangement and rated speed. Due to the limited information provided by the manufacturers, the following assumptions are made in the derating: the machines operate with a steady-state stator winding temperature of 130 \({}^{\circ}\)C and the available cooling is directly proportional to the difference between this and the coolant temperature; at this low speed only the copper loss \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Inlet Coolant Temperature** & **Max. Continuous Power** & **Max. Efficiency** & **Power Density** \\ \hline Proposed IPMSM & 80 \({}^{\circ}\)C & 103 kW & 97\% & 2.08 kW/kg \\ \hline Proposed IM & 80 \({}^{\circ}\)C & 75 kW & 95\% & 1.43 kW/kg \\ \hline eMobility IM [48] & 65 \({}^{\circ}\)C & 49.5 kW & 93\% & 1.04 kW/kg \\ \cline{2-5}  & 80 \({}^{\circ}\)C & 44.5 kW & \(\leq\)93\% & 0.94 kW/kg \\ \hline GVM210-100P [61] & 60 \({}^{\circ}\)C & 55 kW & - & 1.57 kW/kg \\ \cline{2-5}  & 80 \({}^{\circ}\)C & 48 kW & - & 1.37 kW/kg \\ \hline YASA-750 [62] & 40 \({}^{\circ}\)C & 70 kW & 97\% & 1.89 kW/kg \\ \cline{2-5}  & 80 \({}^{\circ}\)C & 49 kW & \(\leq\)97\% & 1.32 kW/kg \\ \hline EMRAX 268 CC [63] & 40 \({}^{\circ}\)C & 105 kW & 98\% & 5.12 kW/kg \\ \cline{2-5}  & 80 \({}^{\circ}\)C & 60.8 kW & \(\leq\)98\% & 2.96 kW/kg \\ \hline AFPMSM [64] & 80 \({}^{\circ}\)C & 20 kW & 91.5\% & 0.88 kW/kg \\ \hline AFPMSM [15] & 80 \({}^{\circ}\)C & 82 kW & 94\% & 2.3 kW/kg \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Comparison of the performance parameters of the designed IPMSM and IM at 2800 rpm with four axial-flux designs available commercially and two from the literature. The reported values for the machines are taken from [15; 45; 59; 60; 61; 62]. Figure 14: Two-dimensional FEA results of induction machines with different numbers of poles designed using the proposed process: (**a**) output power considering the thermal limit, (**b**) core loss/weight (bars) and weight (line). is considered and this loss is proportional to the square of current; and also the torque is proportional to current. The induction machine described in Ref. [48] delivers 115 kW at a rated current and speed of 290 A and 6500 rpm with an inlet coolant of 65 \({}^{\circ}\)C. The output power of the machine is reduced to 49.5 kW at 2800 rpm. Considering a 15 \({}^{\circ}\)C higher temperature of the coolant, the amount of the loss should be reduced by 19%. Thus, the rated current will have a 10% reduction which produces a derated output power of 44.5 kW. The Parker GVM210-100P [61] has a rated power of 106 kW with 60 \({}^{\circ}\)C coolant at 5373 rpm. Thus, this machine offers 55.2 kW output power at 2800 rpm with the 60 \({}^{\circ}\)C inlet coolant. The increase in the inlet temperature to 80 \({}^{\circ}\)C leads to a 13% reduction of the rated current and torque. Therefore, the derated output power of this machine drops to 48 kW with 80 \({}^{\circ}\)C coolant. Therefore, the power density of the machine is 1.37 kW/kg with respect to its 35 kg weight. The YASA-750 is a commercial axial-flux PM machine which is rated at 70 kW and 3000 rpm with 40 \({}^{\circ}\)C coolant [62].