Energy management of hybrid electric propulsion system: Recent progress and a flying car perspective under three-dimensional transportation networks

The hybrid electric propulsion system (HEPS) holds clear potential to support the goal of sustainability in the automobile and aviation industry. As an important part of the three-dimensional transportation network, vehicles and aircraft using HEPSs have the advantages of high fuel economy, low emission, and low noise. To fulfill these advantages, the design of their energy management strategies (EMSs) is essential. This paper presents an in-depth review of EMSs for hybrid electric vehicles (HEVs) and hybrid electric aircraft. First, in view of the main challenges of current EMSs of HEVs, the referenced research is reviewed according to the solutions facing real-time implementation problems, variable driving conditions adaptability problems, and multi-objective optimization problems, respectively. Second, the existing research on the EMSs for hybrid electric aircraft is summarized according to the hybrid electric propulsion architectures. In addition, with the advance in propulsion technology and mechanical manufacturing in recent years, flying cars have gradually become a reality, further enriching the composition of the three-dimensional transportation network. And EMSs also play an essential role in the efficient operation of flying cars driven by HEPSs. Therefore, in the last part of this paper, the development status of flying cars and their future prospects are elaborated. By comprehensively summarizing the EMSs of HEPS for vehicles and aircraft, this review aims to provide guidance for the research on the EMSs for flying cars driven by HEPS and serve as the basis for knowledge transfer of relevant researchers.