Optimization of Electro-Hydraulic System Power Matching for the Main Transmission Chain of Heavy Machinery

Crawler cranes suffer from power mismatch in their electro-mechanical–hydraulic main drive system under sudden load variations and multi-action coupling conditions, which results in low energy utilization efficiency. This study establishes an electro-hydraulic closed-loop transfer function model and proposes a synthetic deviation-driven proportional–integral–derivative power matching control strategy to regulate hydraulic pump displacement. Experiments on a 1250 t crawler crane show that the model is reliable, with the coefficient of determination R2 between simulation and experimental data exceeding 0.94. The strategy improves power matching by 27.33% for the engine–pump link and 18.9% for the full link in single-action conditions, and 12.67% and 8.7% in compound-action conditions. After control, the engine–pump power matching coefficient stabilizes around 1.04 and the full-link coefficient stabilizes within 1.05 to 1.21 under single-action conditions, while under compound-action conditions, the engine–pump coefficient stabilizes within 1.05 to 1.15 and the full-link coefficient stabilizes within 1.0 to 1.25. The control strategy suppresses power mismatch and optimizes system stability and energy efficiency, which provides a technical reference for the optimization of electro-mechanical–hydraulic drive systems in heavy machinery.