Abstract
Pure Electric Mini Hydraulic Excavators (PEMHE), endowed with zero-emission, compactness, and quick dynamic properties, play an indispensable role in confined spaces and scenes demanding rapid, precise operations. Nevertheless, the stringent need for installation space significantly curtails the maximum battery capacity that the excavators can accommodate, subsequently making the enhancement of the average operation time per charge a significant challenge. This paper focuses on alleviating the power shortage conundrum in the PEMHE. Firstly, an appropriate radiator structure is designed based on Computation Fluid Dynamics (CFD) simulation to reduce the rated power of the Thermal Management Control System (TMCS). Secondly, an energy-saving control algorithm is designed for the TMCS. Finally, a dynamic programming (DP)-based offline energy management strategy is proposed for a double-variable hydraulic source made up of a Permanent Magnet Synchronous Motor (PMSM) and an electro-hydraulic proportional displacement control pump. The effectiveness of the proposed theoretical method is validated through simulation. Results demonstrated that the designed radiator traded a limited pressure loss for higher heat dissipation efficiency, and the control algorithm saved 20.8% power in comparison with a traditional set-value control. The proposed offline energy management strategy revealed an energy-saving potential of 1.08 kWh per complete discharge cycle of battery under typical excavation condition. This research provides a benchmark for online energy management strategy development and serves as a reference for energy-saving design in other types of electric hydraulic machinery.
