Functional and Cost-Based Automatic Generator for Hybrid Vehicles Topologies

The energy efficiency of a hybrid electric vehicle is dictated by the topology (coupling option of power sources/sinks), choice (technology), and control of components. The first design area among these, the topology, has the biggest flexibility of them all, yet, so far in the literature, the topology design is limited investigated due to its high complexity. In practice, a predefined small set of topologies is used to optimize their energy efficiency by varying the power specifications of the main components (sizing). By doing so, the complete design of the vehicle is, inherently and to a certain extent, suboptimal. Moreover, various complex topologies appear on the automotive market and no tool exists to optimally choose or evaluate them. To overcome this design limitation, in this paper, a novel framework is presented that deals with the automatic generation of possible topologies given a set of components (e.g., engine, electric machine, batteries, or transmission elements). This paper uses a platform (library of components) and a hybrid knowledge base (functional and cost-based principles) to set up a constraint logic programming problem, and outputs a set of feasible topologies for hybrid electric vehicles. These are all possible topologies that could be built considering a fixed, yet large, set of components. Then, by using these results, insights are given on what construction principles are mostly critical for simulations time, and what topologies could be selected as candidate topologies for sizing and control studies. Such a framework can be used for any powertrain application; it can offer the topologies to be investigated in the design phase and can provide insightful results for optimal design analyses.