Efficiency and suitability analyses of varied drive train architectures for plug-in hybrid electric vehicle (PHEV) applications

As is well known, plug-in hybrid electric vehicles (PHEVs) are predominantly dependant on the energy storage system (ESS), compared to regular HEVs. Although the series PHEV topology has been recently targeted as the prime choice for PHEV applications, it is unclear as to whether or not it is indeed the most efficient option. This paper models PHEVs in both series and parallel structures by using the forward/backward modeling method, to determine the most efficient drive train architecture for future PHEV applications. In general, the drive train efficiency can be simply yielded out by calculating the losses at each power stage in a series or parallel drive train structure. However, the power component stage-based analysis is a practically deficient method. In order to have a fair efficiency comparison, some parameters that directly affect fuel consumption, such as drive train mass and different control strategies should also be taken into consideration. This paper aims at modeling both the series and parallel PHEV drive trains, and further computing and comparing their absolute drive train efficiencies. Furthermore, the resultant ESS charging profiles, discharging profiles, as well as roundtrip efficiencies are calculated and studied.