Thermal Model Approach to the YASA Machine for In-Wheel Traction Applications

Abstract

The axial-flux permanent magnet (AFPM) machines with yokeless and segmented armature (YASA) topology are suitable for in-wheel traction systems due to the high power density and efficiency. To guarantee the reliable operation of the YASA machines, an accurate thermal analysis should be undertaken in detail during the electrical machine design phase. The technical contribution of this paper is to establish a detailed thermal analysis model of the YASA machine by the lumped parameter thermal network (LPTN) method. Compared with the computational fluid dynamics (CFD) method and the finite element (FE) method, the LPTN method can obtain an accurate temperature distribution with low time consumption. Firstly, the LPTN model of each component of the YASA machine is constructed with technical details. Secondly, the losses of the YASA machine are obtained by the electromagnetic FE analysis. Then, the temperature distribution of the machine can be calculated by the LPTN model and loss information. Finally, a prototype of the YASA machine is manufactured and its temperature distribution under different operating conditions is tested by TT-K-30 thermocouple temperature sensors. The experimental data matches the LPTN results well.

Multi-Objective Optimization of Yokeless and Segmented Armature Machine for In-Wheel Traction Applications Based on the Taguchi Method

“…Finally, the accuracy of the optimization process is experimentally verified by the prototyped machine with optimal variables. For future study, the combination of thermal network models in [20] and the proposed Taguchi method here would be a good direction, and other useful analytical models for machine design can also be included. The load test was carried out, and the torque current curve of the prototype was measured as shown in Figure 21.…”

“…And the main magnetic flux starts from the permanent magnet-N and passes through the stator core to the permanent magnet-S on the other side. After passing through the rotor core on the second side, the flux starts from the N-pole on the second side and passes through the stator core to the S-pole on the first side, and the main magnetic flux forms a closed loop [20]. The main design objectives of the 5 kW YASA machine applied on the in-wheel traction system are shown in Table 1.…”

Performance evaluating of rotor arrangement on high torque density in‐wheel permanent magnet machines

“…However, the PMs can be demagnetised due to armature winding temperature under peak torque. Some of yokeless and segmented armature (YASA) axial flux in-wheel motors are proposed and analysed since their higher torque density compared with radial flux motors [15,16]. In addition, the absence of the stator yoke in the YASA type makes it more efficient and higher power density.…”