A Composite Control Strategy for an Integrated Air-Water Power System under Abrupt Load Variation during the Water-Entry Process

Aerial-underwater trans-medium vehicles have attracted significant interest due to their multi-domain operational capability. However, the performance of existing power systems in such vehicles remains a limiting factor for further improvements in speed and endurance. This paper introduces an integrated air-water power system, which enhances both the configuration and energy conversion mechanisms of conventional systems. Nevertheless, during the water-entry process, the power system undergoes a wide-range abrupt load change, resulting in transient energy loss and potential instability. To address this issue, a mathematical model is developed to describe the dynamic behavior of the system. A composite strategy of closed-loop speed control with active logical commands is proposed for the dynamic energy conversion process. Numerical simulations and hardware-in-the-loop (HIL) tests are carried out to validate the effectiveness of the control strategy. Both simulation and experimental results demonstrate that the proposed control strategy can effectively suppress the overspeed risks induced by instantaneous 90% load reduction. The closed-loop speed control alone can mitigate the load disturbance after entering water. The proposed control strategy for energy conversion enhances the system’s responsiveness to abrupt load variations, thereby preventing energy loss and equipment damage. This research offers insight into the development of novel integrated air-water power systems.