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Controls and Standards for Interoperable Wireless Power Transfer in Unmanned and Autonomous Systems 

By Dr. Alex Phipps, Dr. Maxwell Kerber, Dr. Graham Sanborn

Unmanned and autonomous systems are used extensively for Navy missions and will continue to play a large role in future Navy and joint scenarios. While most of these systems are able to perform their mission without human interaction, limitations in the amount of power that can be stored place a fundamental limit on the overall system autonomy. Inductive wireless power transfer provides a way to recharge unmanned systems (vehicles, sensors, etc.) at close proximity without the need for direct electrical contact through wires or electrodes. This type of inductive power transfer has been demonstrated at power levels ranging from a few watts to kilowatts, and from applications ranging from personal electronics to automotive. One challenge with implementing wireless power transfer for unmanned Navy applications is the vast array of systems to be charged due to variations in power levels, physical dimensions, and other operational requirements. Additionally, autonomy of the power transfer operation itself must be achieved (i.e. it must start and stop without external involvement). A few wireless power transfer systems have been demonstrated, but are either vendor or platform specific. This work presents the development of hardware and algorithms for autonomous, inductive wireless power transfer that is geared towards interoperability across an array of Navy systems. Specifically, the presented system demonstrates initiation, monitoring, and termination of power transfer with a battery to battery efficiency of close to 70%. The framework of a wireless power transfer standard is also presented, which provides interoperability by allowing systems of different power levels and charge rates to be charged from a single charging station.