High efficiency operation of a hybrid electric vehicle starter/generator over road profiles

Efficient operation of induction motor starter/generator systems is an important part of the power management function that is required in the self contained vehicular environment. This paper characterizes the performance of a fuzzy logic controller for a hybrid electric vehicle starter/generator that is used to maintain optimum efficiency operation under both steady state and dynamic loading conditions. In steady state, automatic mapping of the maximum efficiency operating points is achieved. In-vehicle dynamic loading is emulated in the laboratory using a motor development platform that can replay industry standard FTP75 road profiles and apply them to the starter/generator. The effects of velocity transients and the bandwidth of the fuzzy controller on efficiency are presented. The effectiveness of the fuzzy controller in maintaining high efficiency operation and in reduced heating is demonstrated.