Analysis of Different Energy Management Strategies for Complex Hybrid Electric Vehicles

The performance of Hybrid Electric Vehicles (HEVs) is strongly affected by their powertrain control strategies, in particular when complex architectures are concerned. Therefore the purpose of this paper is to analyze, through numerical simulation, different methodologies to develop an energy management strategy aiming to minimize the overall CO2 emissions of the vehicle. In order to perform a comprehensive comparison, different optimization algorithms were selected among the available solutions in the control theory. Foremost a global optimization strategy, the Dynamic Programming (DP), was used to benchmark the performance of the energy management systems. Then a local optimization strategy, the Equivalent Consumption Minimization Strategy (ECMS), was evaluated, to prove its suboptimal performance and to evaluate the possibility to be implemented on a real Engine Control Unit (ECU). Finally, the potential of heuristic control techniques was evaluated due to their low computational requirements and since they represent the most common solution in real applications. The analysis focused on the case study architecture of the Chevrolet Volt, for which a Simulink model was built and tested on both regulatory driving cycles and real world driving conditions, emphasizing pro and cons of each method.