9 research outputs found
Adaptive Distributed Laser Charging for Efficient Wireless Power Transfer
Distributed laser charging (DLC) is a wireless power transfer technology for
mobile electronics. Similar to traditional wireless charging systems, the DLC
system can only provide constant power to charge a battery. However, Li-ion
battery needs dynamic input current and voltage, thus power, in order to
optimize battery charging performance. Therefore, neither power transmission
efficiency nor battery charging performance can be optimized by the DLC system.
We at first propose an adaptive DLC (ADLC) system to optimize wireless power
transfer efficiency and battery charging performance. Then, we analyze ADLC's
power conversion to depict the adaptation mechanism. Finally, we evaluate the
ADLC's power conversion performance by simulation, which illustrates its
efficiency improvement by saving at least 60.4% of energy, comparing with the
fixed-power charging system.Comment: 5 pages, 9 figure
Resonant Beam Communications with Photovoltaic Receiver for Optical Data and Power Transfer
The vision and requirements of the sixth generation (6G) mobile communication
systems are expected to adopt freespace optical communication (FSO) and
wireless power transfer (WPT). The laser-based WPT or wireless information
transfer (WIT) usually faces the challenges of mobility and safety. We present
a mobile and safe resonant beam communication (RBCom) system, which can realize
high-rate simultaneous wireless information and power transfer (SWIPT). We
propose an analytical model to depict its carrier beam and information transfer
procedures. The numerical results show that RBCom can achieve more than 40 mW
charging power and 1:6 Gbit/s channel capacity with orthogonal frequency
division multiplexing (OFDM) scheme, which can be applied in future scenario
where power and high-rate data are simultaneously desired
Earning Maximization with Quality of Charging Service Guarantee for IoT Devices
Resonant Beam Charging (RBC) is a promising Wireless Power Transfer (WPT)
technology to provide long-range, high-power, mobile and safe wireless power
for the Internet of Things (IoT) devices. The Point-to-Multipoint (PtMP) RBC
system can charge multiple receivers simultaneously similar to WiFi
communications. To guarantee the Quality of Charging Service (QoCS) for each
receiver and maximize the overall earning in the PtMP RBC service, we specify
the Charging Pricing Strategy (CPS) and develop the High Priority Charge (HPC)
scheduling algorithm to control the charging order and power allocation. Each
receiver is assigned a priority, which is updated dynamically based on its
State of Charging (SOC) and specified charging power. The receivers with high
priorities are scheduled to be charged in each time slot. We present the pseudo
code of the HPC algorithm based on quantifying the receiver's SOC, discharging
energy and various relevant parameters. Relying on simulation analysis, we
demonstrate that the HPC algorithm can achieve better QoCS and earning than the
Round-Robin Charge (RRC) scheduling algorithm. Based on the performance
evaluation, we illustrate that the methods to improve the PtMP RBC service are:
1) limiting the receiver number within a reasonable range and 2) prolonging the
charging duration as long as possible. In summary, the HPC scheduling algorithm
provides a practical strategy to maximize the earning of the PtMP RBC service
with each receiver's QoCS guarantee
Fair Scheduling in Resonant Beam Charging for IoT Devices
Resonant Beam Charging (RBC) is the Wireless Power Transfer (WPT) technology,
which can provide high-power, long-distance, mobile, and safe wireless charging
for Internet of Things (IoT) devices. Supporting multiple IoT devices charging
simultaneously is a significant feature of the RBC system. To optimize the
multi-user charging performance, the transmitting power should be scheduled for
charging all IoT devices simultaneously. In order to keep all IoT devices
working as long as possible for fairness, we propose the First Access First
Charge (FAFC) scheduling algorithm. Then, we formulate the scheduling
parameters quantitatively for algorithm implementation. Finally, we analyze the
performance of FAFC scheduling algorithm considering the impacts of the
receiver number, the transmitting power and the charging time. Based on the
analysis, we summarize the methods of improving the WPT performance for
multiple IoT devices, which include limiting the receiver number, increasing
the transmitting power, prolonging the charging time and improving the
single-user's charging efficiency. The FAFC scheduling algorithm design and
analysis provide a fair WPT solution for the multi-user RBC system
TDMA in Adaptive Resonant Beam Charging for IoT Devices
Resonant beam charging (RBC) can realize wireless power transfer (WPT) from a
transmitter to multiple receivers via resonant beams. The adaptive RBC (ARBC)
can effectively improve its energy utilization. In order to support multi-user
WPT in the ARBC system, we propose the time-division multiple access (TDMA)
method and design the TDMA-based WPT scheduling algorithm. Our TDMA WPT method
has the features of concurrently charging, continuous charging current,
individual user power control, constant driving power and flexible driving
power control. The simulation shows that the TDMA scheduling algorithm has high
efficiency, as the total charging time is roughly half (46.9% when charging 50
receivers) of that of the alternative scheduling algorithm. Furthermore, the
TDMA for WPT inspires the ideas of enhancing the ARBC system, such as flow
control and quality of service (QoS)
Adaptive Resonant Beam Charging for Intelligent Wireless Power Transfer
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.Comment: 12 pages, 24 figures, IEEE Internet of Things Journa
Wireless Energy Transmission Channel Modeling in Resonant Beam Charging for IoT Devices
Power supply for Internet of Things (IoT) devices is one of the bottlenecks
in IoT development. To provide perpetual power supply to IoT devices, resonant
beam charging (RBC) is a promising safe, long-range and high-power wireless
power transfer solution. How long distance can RBC reach and how much power can
RBC transfer? In this paper, we analyze the RBC's consistent and steady
operational conditions, which determine the maximum power transmission
distance. Moreover, we study the power transmission efficiency within the
operational distance, which determines the deliverable power through the RBC
energy transmission channel. Based on this energy transmission channel
modeling, we numerically evaluate its impacts on the RBC system performance in
terms of the transmission distance, the transmission efficiency, and the output
electrical power. The analysis leads to the guidelines for the RBC system
design and implementation, which can deliver multi-Watt power over multi-meter
distance wirelessly for IoT devices
Channel-Dependent Scheduling in Wireless Energy Transfer for Mobile Devices
Resonant Beam Charging (RBC) is the Wireless Power Transfer (WPT) technology,
which can provide high-power, long-distance, mobile, and safe wireless charging
for Internet of Things (IoT) devices. Supporting multiple IoT devices charging
simultaneously is a significant feature of the RBC system. To optimize the
multi-user charging performance, the transmitting power should be scheduled for
charging all IoT devices simultaneously. In order to keep all IoT devices
working as long as possible for fairness, we propose the First Access First
Charge (FAFC) scheduling algorithm. Then, we formulate the scheduling
parameters quantitatively for algorithm implementation. Finally, we analyze the
performance of FAFC scheduling algorithm considering the impacts of the
receiver number, the transmitting power and the charging time. Based on the
analysis, we summarize the methods of improving the WPT performance for
multiple IoT devices, which include limiting the receiver number, increasing
the transmitting power, prolonging the charging time and improving the
single-user's charging efficiency. The FAFC scheduling algorithm design and
analysis provide a fair WPT solution for the multi-user RBC system.Comment: 11 pages, 12 figure
Wireless Power Transmitter Deployment for Balancing Fairness and Charging Service Quality
Wireless Energy Transfer (WET) has recently emerged as an appealing solution
for power supplying mobile / Internet of Things (IoT) devices. As an enabling
WET technology, Resonant Beam Charging (RBC) is well-documented for its
long-range, high-power, and safe "WiFi-like" mobile power supply. To provide
high-quality wireless charging services for multi-user in a given region, we
formulate a deployment problem of multiple RBC transmitters for balancing the
charging fairness and quality of charging service. Based on the RBC
transmitter's coverage model and receiver's charging / discharging model, a
Genetic Algorithm (GA)-based and a Particle Swarm Optimization (PSO)-based
scheme are put forth to resolve the above issue. Moreover, we present a
scheduling method to evaluate the performance of the proposed algorithms.
Numerical results corroborate that the optimized deployment schemes outperform
uniform and random deployment in 10%-20% charging efficiency improvement