Energy performance optimization for a UAV-based laser wireless power transfer system

The endurance limitation of unmanned aerial vehicles (UAVs) is a critical challenge hindering their widespread application. Laser Wireless Power Transfer (LWPT) technology, with its advantages including long transmission distances and high power, presents a promising solution for energy supplementation. Nevertheless, in flight environments, LWPT systems encounter multiple challenges—spillover losses arising from beam spot-to-photovoltaic (PV) array mismatch due to varying transmission distances and electric mismatch losses caused by non-uniform irradiation induced by changes in UAV attitude. This paper develops a “transmitter-beam distribution-PV array” coupled model to simulate the optical-thermal-electrical multi-physics coupling characteristics of the PV array, considering varying transmission distances, pointing errors, and attitudes. Furthermore, a zoom system based on a dynamic beam waist adjustment method is proposed to optimize the beam waist radius for varying transmission distances, thereby effectively reducing spillover loss. Results indicate that the zoom system improves cut-off efficiency and extends the effective power transmission range compared to a fixed-focus system. While the received power loss from normal deviation follows the expected geometric cosine law, the study reveals that the radial deviation angle significantly exacerbates electrical mismatch. When the radial deviation angle reaches a maximum of 45°, the mismatch loss rate attains 32%, leading to a 13.74% decrease in output power due to non-uniform sub-module activation. Under pointing error conditions (20 mm,45°), system efficiency decreased by 48%. The findings of this study are valuable for achieving efficient power transfer for UAV-based LWPT systems.