Thermal design of a magnet-free axial-flux switch reluctance motor for automotive applications

Abstract

With the requirement to develop magnet-free motors for automotive application, more design effort is needed for thermal design as the machine temperature limits the motor performance. Thermal design procedure of automotive motor has to fully exploit the modern approaches in electrical machine thermal analysis in terms of accuracy and solving time. This paper proposes a computational-cost-effective way to obtain the optimum thermal design of an axial-flux switched reluctance motor by means of lumped circuit methods with some inputs from Computational Fluid Dynamic simulations.

Review on Thermal Behavior and Cooling Aspects of Axial Flux Permanent Magnet Motors–A Mechanical Approach

“…LPM is identical to the electrical circuit network [12]. It is used for detailed duty cycle evaluation with reasonable accuracy and minimal computational cost [13]. The analytical lumped circuit technique has the benefit of being extremely fast [14].…”

Axial flux switched reluctance machines: a comprehensive review of design and topologies

“…But due to the higher core losses in the high frequency for high-speed structures, the temperature of these parts may be higher than others. For instance, a thermal analysis was performed for the CS-AFSRM in [38], the results of which can be seen in Fig. 16.…”

“…Applications: Unique features of AFSRMs have made them highly functional in the propulsion industry such as utilisation like the in-wheel motors (IWMs) for electric vehicles [30,32,[35][36][37][38][39][40][41][42], electrical powertrains [43], scooters [44,45], microelectromechanical systems (MEMS) for semiconductor industries [46,47], wind turbines [48] and simpler applications like fan [49]. Although for applications such an electric vehicle propulsion, there are some of the following limitations that can be solved to a target point: the torque density of the SRM is less than that of a competitors with magnets, which means that the machine may need more current for same power transmission.…”

Lumped Parameter Thermal Modeling of Permanent Magnet Synchronous Motor

“…These approaches have advantages and disadvantages, one of the main difference being the solving time. Once the thermal models are setup, the computational cost of analytical LPTN method is less demanding when compared to the numerical methods [7]. FEM is mainly focused on electromagnetic modeling which provides for example electromagnetic torque-time graph of the motor.…”