Power Control Algorithm for Hybrid Excavator with Super Capacitor

This paper shows several structures of the hybrid excavator with the super capacitor and compares with each other at the view point of the fuel economy, the additional cost due to the hybridization, and the expected payback time. According to the comparison result, it can be concluded that a compound type hybrid structure is better solution than others because of its short expected payback time and higher reliability. And also, the power control algorithm of the engine and the super capacitor is proposed. To verify the proposed algorithm, the computer simulation is performed and the results are presented. The simulation results show that by hybridization, the fuel consumption can be reduced by about 24% compared to the conventional hydraulic excavator. The hardware implementation is now in progress for a 22 ton class excavator.