Multiuser Charging Control in Wireless Power Transfer via Magnetic Resonant Coupling

TL;DR

This paper investigates multiuser wireless power transfer via magnetic resonant coupling, addressing fairness issues caused by distance differences, and proposes algorithms to optimize load resistances for efficient power delivery.

Contribution

It introduces a closed-form power expression for multiuser MRC-WPT systems, identifies a near-far fairness problem, and develops centralized and distributed algorithms for load resistance optimization.

Findings

Closed-form power delivery expressions derived.

Identified near-far fairness issue in multiuser WPT.

Proposed algorithms improve power transfer efficiency and fairness.

Abstract

Magnetic resonant coupling (MRC) is a practically appealing method for realizing the near-field wireless power transfer (WPT). The MRC-WPT system with a single pair of transmitter and receiver has been extensively studied in the literature, while there is limited work on the general setup with multiple transmitters and/or receivers. In this paper, we consider a point-to-multipoint MRC-WPT system with one transmitter sending power wirelessly to a set of distributed receivers simultaneously. We derive the power delivered to the load of each receiver in closed-form expression, and reveal a "near-far" fairness issue in multiuser power transmission due to users' distance-dependent mutual inductances with the transmitter. We also show that by designing the receivers' load resistances, the near-far issue can be optimally solved. Specifically, we propose a centralized algorithm to jointly optimize the load resistances to minimize the power drawn from the energy source at the transmitter under given power requirements for the loads. We also devise a distributed algorithm for the receivers to adjust their load resistances iteratively, for ease of practical implementation.