Adaptive Resonant Beam Charging for Intelligent Wireless Power Transfer

TL;DR

This paper introduces an adaptive resonant beam charging system that uses feedback control and DC-DC conversion to optimize battery charging, significantly reducing energy waste and improving safety in wireless power transfer.

Contribution

It presents a novel adaptive control method for RBC-based wireless power transfer, enabling dynamic power adjustment based on battery needs, which was not addressed in prior RBC systems.

Findings

ARBC saves 61% of battery charging energy

ARBC reduces supplied energy by 53%-60% compared to RBC

ARBC achieves high energy efficiency especially in inefficient WPT conditions

Abstract

As a long-range high-power wireless power transfer (WPT) technology, resonant beam charging (RBC) can transmit Watt-level power over long distance for the devices in the internet of things (IoT). Due to its open-loop architecture, RBC faces the challenge of providing dynamic current and voltage to optimize battery charging performance. In RBC, battery overcharge may cause energy waste, thermal effects, and even safety issues. On the other hand, battery undercharge may lead to charging time extension and significant battery capacity reduction. In this paper, we present an adaptive resonant beam charging (ARBC) system for battery charging optimization. Based on RBC, ARBC uses a feedback system to control the supplied power dynamically according to the battery preferred charging values. Moreover, in order to transform the received current and voltage to match the battery preferred charging values, ARBC adopts a direct current to direct current (DC-DC) conversion circuit. Relying on the analytical models for RBC power transmission, we obtain the end-to-end power transfer relationship in the approximate linear closed-form of ARBC. Thus, the battery preferred charging power at the receiver can be mapped to the supplied power at the transmitter for feedback control. Numerical evaluation demonstrates that ARBC can save 61% battery charging energy and 53%-60% supplied energy compared with RBC. Furthermore, ARBC has high energy-saving gain over RBC when the WPT is unefficient. ARBC in WPT is similar to link adaption in wireless communications. Both of them play the important roles in their respective areas.