Efficient Wireless Power Transfer for Heterogeneous Adaptive IoT Systems

To support the demand for energy autonomy, many of the future IoT edge devices will be powered from non-conventional, energy harvesting and wireless power sources. While convenient, sustainable, and robust, wireless power transfer (WPT) exhibits limited efficiency compared with the traditional wired power approaches, presenting a primary design challenge for practical IoT systems. Non-radiative mid-range WPT from a single power source to several power loads and from several power sources to a single power load has recently been experimentally demonstrated. Alternatively, WPT among multiple, simultaneously transmitting and receiving devices is a primary concern in future IoT systems with numerous interconnected heterogeneous objects. Furthermore, the dynamic nature of certain distributed IoT systems has a significant effect on WPT interactions among the numerous, mobile in space power devices. WPT that exploits the lossless characteristics of strong-coupled resonant regime is explored in this work as a method for efficiently transferring power among multiple, dynamically connected and disconnected IoT end devices. The efficiency of the power transfer is investigated in dense and sparse IoT systems in terms of the number of IoT devices located within limited space. Based on the results of this work, interactions among wirelessly powered devices have significant effect on the power transfer. Efficiency of power transfer increases with increasing transmitter-receiver coupling. Alternatively, densely clustered power transmitters or receivers may degrade the system-wide power transfer and efficiency. Intuition behind systematically optimized utilization of the WPT-based energy budget in future IoT systems is also provided.