Integrated Multi-Criteria Control of a Dual-Channel Electric Pump-Fed Propellant Feed System for a Small Liquid Rocket Engine Under Energy and Thermal Constraints

Electric pump-fed liquid rocket engines require coordinated propellant delivery under coupled hydraulic, electrical, actuator, and thermal constraints. This study develops an integrated reduced-order model of a dual-channel electric pump-fed propellant system, including the battery and DC bus, power converters, two independently driven motor–pump units, hydraulic feed lines, control valves, combustion chamber, and thermal states. A hierarchical constrained multi-criteria supervisory controller is formulated to regulate chamber pressure, oxidizer-to-fuel mixture ratio, feed-channel coordination, electrical loading, and thermal response. Performance is compared with a conventional PI controller and an enhanced PI configuration incorporating feedforward and disturbance compensation under nominal, degraded, long-duration, and constraint-active scenarios. Relative to the baseline PI controller, the proposed controller reduced the startup pressure peak from 2.64 to 2.32 MPa, pressure RMSE from 0.016 to 0.006 MPa, and mean branch synchronization error from 0.112 to 0.028 MPa. The minimum battery voltage increased from 87.0 to 90.4 V, while the peak motor current decreased from approximately 88 to 65 A. In the 1800 s thermal case, the maximum fuel-drive temperature decreased from approximately 104 to 74 °C. Numerical verification and comparison with published experimental benchmarks supported the physical plausibility and equilibrium-scale behavior of the reduced-order model, while differences in absolute transient time scales limit its use for quantitative prediction of hardware transient dynamics. The results indicate improved coordinated control within the investigated operating envelope and support the use of the framework for comparative system-level assessment and preliminary design of small-class electric-pump propulsion systems.