Thermal Optimization Design of the Electro-Hydraulic Power System Based on Phase Change Heat Storage Units

Green aviation demands lightweight, highly efficient electro-hydraulic power system for flight-critical actuation. However, transient thermal coupling among motor, pump and oil tank can trigger lubricant degradation and insulation failure, jeopardizing safety and efficiency. To close this gap, we develop a first-principles dynamic thermal system model that captures coupled electro-mechanical-thermofluidic interactions over the full flight envelope. Parametric simulations reveal that load pressure, motor speed, working fluid and ambient temperature jointly drive component temperatures up to 42% above nominal within 60s under extreme duty cycles. Aiming to decouple transient peaks from steady-state design limits, we integrate a discrete fin-coupled a compact phase change heat storage unit (PCHSU). Dynamic simulations show that the PCTSU reduces peak temperatures of the motor, pump and oil tank by 7.7%, 13.6% and 2.9%, respectively, while cutting thermal swing amplitude by 30% and entropy generation by 4.1%, equivalent to a 3.2% reduction in electrical energy for identical hydraulic output. The proposed model and control framework offers a lightweight, theory-driven route to enhance thermal reliability and energy efficiency of electro-hydraulic power systems, directly supporting the transition toward low-carbon, high-performance aircraft.