Decoupled Current-Sharing Strategy for A Novel Integrated Starter/Generator Converter Applied in UAV Power Generation System

To address the critical challenges of efficiency enhancement, cost reduction, and system reliability in low-voltage high-current (LVHC) power generation system for small low-altitude transport unmanned aerial vehicles (UAVs), this paper proposes a novel integrated starter/generator (ISG) power conversion architecture with a single DC bus current sensor. In this architecture, multiphase interleaved buck converters are employed, and a double closed-loop controller is typically adopted to regulate the output voltage. Additionally, a current-sharing loop is implemented to ensure a balanced distribution of inductor currents. However, coupling between loops can cause the current sharing process to affect the output voltage regulation. To address this problem, a decoupled current-sharing control method is proposed, ensuring mutual noninterference between output voltage regulation and inductor current-sharing. In this paper, the innovative aspects of the proposed power conversion architecture are first highlighted, followed by the development of a small-signal model. The principles of the decoupled current-sharing strategy and the phase current reconstruction method are elaborated comprehensively. Building on this, the proposed strategy employs a parallel loop structure, which effectively mitigates loop coupling. Quantitative analysis reveals that the coupling degree between the loops of the proposed strategy is negligible across the full operating range. Furthermore, controller loop parameters are meticulously designed to enhance system stability and dynamic performance. Finally, a 3-kW integrated starter/generator converter (ISGC) prototype is developed. Experimental results validate the effectiveness of the proposed architecture and strategy, demonstrating their practical applicability and superiority in the UAV power generation system.