Analysis of different forced convection cooling systems for belt-driven starter-generator

This paper deals with the cooling management of a belt-driven starter generator for mild-hybrid electric vehicles. The functionalities required to the system are the start-and-stop, torque assistance, regenerative braking and on board electrical power generation. Due to the strict constrains imposed by the application, the design of the electrical machine is challenging from the electromagnetic, thermal and mechanical points of view. Both air and liquid forced convection cooling systems have been considered and experimentally investigated according to the required power losses and duty cycle. Thermal measurements have been conducted on ad hoc prototype equipped with both the cooling systems. For the considered application, the results demonstrate the applicability of the liquid cooling solution only.