Hyeon-Seop Yi1, Jin-Beom Jeong, Suk-Won Cha#, and Chun-Hua Zheng
The powertrain of hybrid vehicles has been a major research issue due to the power distribution by the combination of mechanical energy. The power distribution of engines and motors have been determined by optimal control or rule-based control. However, the hybrid powertrain, which includes fuel cells, is a major research issue because the fuel cells and batteries support the motors. Recently, there have been many cases of using such fuel cell powertrains among construction machinery. In a fuel cell hybrid excavator, the fuel cell is responsible for most of the workload, and the battery supplement the fuel cell. Depending on the amount of battery support, the excavator can handle a larger workload; however, it is necessary to have an effective operating strategy that consider the battery state of charge (SOC). It is important to select the appropriate capacity for the fuel cell and battery. Therefore, this paper investigated the working power of an engine excavator and the component sizing of a fuel cell-battery excavator. The background control theory of component sizing is dynamic programming and this study suggests an operational strategy. It also suggests optimal capacities for both power sources and establishes a baseline for them.