Adaptive Filter-based Energy Management Strategy For Hybrid Energy Storage in Electric Excavator Systems

This paper proposes a load-variation-rate-based adaptive time-constant energy management strategy for a hybrid energy storage system in electric excavators. Electric excavators experience rapid power variations and regenerative energy during digging and swing operations; therefore, an effective power distribution strategy is required to reduce battery stress. The proposed method adjusts the filter time constant according to the load variation rate. During rapid load changes, the time constant is increased to suppress abrupt variations in the battery power reference, allowing the supercapacitor to handle transient and high-frequency power components. An electric excavator load profile was generated using an AMESim-based model and extended to an 8-hour operating condition. Simulation results reveal that the proposed method maintains a final battery SOC at 0.261, compared with 0.219 for the fixed-time-constant method. The battery DOD is also reduced from 0.630 to 0.588, while the estimated battery cycle life is improved by approximately 10.12%. Overall, these results indicate that the proposed energy management strategy reduces battery discharge burden and improves the operational performance of hybrid energy storage systems for electric excavators.