Energy management strategy to be used in design space exploration for electric powertrain optimization

Electric vehicle (EV) design offers additional degrees of freedom in powertrain layout. A tremendous number of topologies have to be compared to find the best one for a given set of requirements. An integrated approach is needed to increase powertrain efficiency not only on component level. In this paper a design space exploration (DSE) method is presented to study interdependencies of all involved components. The research is done for topologies with multiple motors (AWD) combined with multiple-speed gearboxes. The objective is a holistic topology optimization to increase driving range. The DSE's key element which defines the energy management strategy (EMS) and computes consumption is discussed in detail. Dynamic programming (DP) is used to determine the most energy efficient operation strategy for the respective topology. Different methods for EMS definition are compared in terms of predicted load collectives, energy efficiency and computing time. Measures to reduce the prediction error for a fast backwards simulation are presented.