Thermal evaluation of different drive train topologies for electric/hybrid vehicles

The aim of this paper is to study the influence of the drive train topology on the temperature of the different components in permanent magnet synchronous motor (PMSM) drives applied to electric/hybrid vehicles. The temperature is a critical parameter because it is directly related to the lifetime and reliability of a device. This is particular important for PMSMs since it also influences the magnetic flux produced by the permanent magnets. Thus, in this paper two different drive train topologies applied to electric/hybrid vehicles are evaluated. The first one comprises a battery pack that directly supplies the inverter, and a PMSM. In the second topology, a step-up bidirectional dc-dc converter is connected between the batteries and the inverter dc supply. A variable voltage control is also applied in this topology to control the inverter supplying voltage. A detailed temperature analysis is presented in the format of three-dimension maps that allow to compare both topologies.