A combinable wireless power transfer design for extensible-capacity and adaptive charging of route UAVs with active ripple mitigation

Abstract

This paper presents a combinable wireless power transfer (WPT) system for unmanned aerial vehicles (UAVs) with autonomous and adaptive charging of extensible capacity. By combining multiple transmission modules in parallel to power the UAV, the charging capacity of the system is dramatically enhanced and is adaptive to multiple power ratings with more flexibility. Meanwhile, the combination provides an approach for the system to improve reliability as each module can be operated independently. The mapping relationship between the transmitter (Tx) and the receiver (Rx) is investigated to estimate the amplitude and phase of output currents from the primary side. An active current ripple mitigation scheme based on real-time current estimation is proposed to regulate the Rx currents from the primary side and mitigate the synthetic current ripple without massive sensors onboard, by utilizing the interleaving technique, the output can achieve current ripple cancellation. And the experiment of a scaled-down prototype verifies that the output power of the combinable configuration is boosted up by 145.5% compared with that of a single module, meanwhile, the active ripple mitigation can indeed ameliorate the charging performance and prolong the battery life, the synthetic ripple amplitude is weakened remarkably by 79.06% whereas the efficiency is measured 5% higher than the system without ripple mitigation.