Uncrewed Systems Technology 043 l Auve Tech Iseauto taxi l Charging focus l Advanced Navigation Hydrus l UGVs insight l MVVS 116 l Windracers ULTRA l CES 2022 show report l ECUs focus I Distant Imagery

46 Focus | Battery charging for maritime use to charge autonomous electric boats when they dock. A coil mounted vertically on a dock can couple with a coil on a boat to provide charging at the quayside. The same coils as the bus system are being used on electric passenger ferries aligned on a pontoon. This has been implemented in a fjord in Norway, where there is limited movement of the water, and gives 2.8 kWh of top-up charging. Dynamic charging The challenge for wireless charging is to extend the static charging capability to moving systems. One system for dynamic charging is a 100 mm-diameter cable that can be 20 m long and installed every 40 m, and is added into the road when it is being built. The system essentially has two rails in the concrete that are designed to avoid the EMI between the cables and to reinforce the sinusoidal feed that provides the charging. A demonstration system in Belgium has achieved 160 kW of charging to vehicles travelling at up to 60 kph. A different system being tested in Sweden and Israel uses coils deployed 8 cm under the surface, which is activated only when a vehicle drives over it. Dynamic charging in the air is an even bigger challenge. A charger system that can harvest RF energy from a 12 kW source is being used to recharge an airborne UAV. The key has been the design of the AC-DC receiver module. This converts a 600 V RMS AC signal at 130 kHz into a 50 V, 120 A DC line with 99.5% efficiency, but weighing just 80 g. This can charge a UAV battery while in the air in only 6 minutes at a charging rate of 10 C in a 3 m-diameter circle from a 6 m-high mast. One module can handle up to 6 kW of power transmission, or two modules to support 12 kW of charging. Conclusion New technologies are emerging for charging unmanned systems, and while wireless charging is finding new ways to boost the power levels and speed up charging, so wired systems are finding new ways to connect reliably and safely at higher power rates. Machine learning and computer vision are allowing existing connector technologies to be applied to unmanned vehicles with high power connectivity and fast charging. Acknowledgements The author would like to thank Andrea Puiatti at Skycharge, Patrick Ahern and John Podrovitz at Colorado Drone Chargers, Sebastian Demuth at Easelink, Stefan Perras at Siemens Technology, Aya Kantor at Powermat Technologies, Ben Waters and Matt Carlson at WiBotic, and Sergio Perez at IPT Technology for their help with researching this article. April/May 2022 | Unmanned Systems Technology AUSTRALIA Lumen   + 61 3 8787 1000 www.lumen.com.au AUSTRIA Easelink   + 43 316 931 2420 www.easelink.com CANADA Solace Power +1 709 745 6099 www.solace.ca WiBotic +1 650 265 7987 www.wibotic.com GERMANY IPT Technology +49 7628 692 96 0 www.ipt-technology.com Siemens Technology – www.siemens.com Skycharge +49 172 5823 844 www.skycharge.de Skysense +49 152 5850 9872 www.skysense.co ISRAEL Powermat Technologies +972 2 995 0500 www.powermat.com JAPAN Nichicon Corp – www.nichicon.co.jp SPAIN Divisek Systems – www.diviseksystems.com SWITZERLAND ABB – www.abb.com US Aerojet Rocketdyne +1 916 355 4000 www.rocket.com Colorado Drone Chargers +1 719 776 9146 www.coloradodronechargers.com Evatran +1 804 918 9517 www.pluglesspower.com Some examples of charging systems suppliers