A 65nm CMOS Process Li-ion Battery Charging Cascode SIDO Boost Converter with 89% Maximum Efficiency for RF Wireless Power Transfer Receiver

Electronic devices usually operate in a variable loading condition and the power transfer efficiency of the accompanying wireless power transfer (WPT) method should be optimizable to a variable load. In this paper, a reconfigurable WPT technique is introduced to maximize power transfer efficiency in a weakly coupled, variable load wireless power transfer application. A series-series two-coil wireless power network with resonators at a frequency of 150 kHz is presented and, under a variable loading condition, a shunt capacitor element is added to compensate for a maximum efficiency state. The series capacitance element of the secondary resonator is tuned to form a resonance at 150 kHz for maximum power transfer. All the capacitive elements for the secondary resonators are equipped with reconfigurability. Regardless of the load resistance, this proposed approach is able to achieve maximum efficiency with constant power delivery and the power present at the load is only dependent on the input voltage at a fixed operating frequency. A comprehensive circuit model, calculation and experiment is presented to show that optimized power transfer efficiency can be met. A 50 W WPT demonstration is established to verify the effectiveness of this proposed approach.

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Maximum Efficiency Point Tracking Method for Multi-Coil Wireless Power Transfer Systems

2021 IEEE 19th International Power Electronics and Motion Control Conference (PEMC) ◽

10.1109/pemc48073.2021.9432551 ◽

2021 ◽

Author(s):

Krystian Frania ◽

Zbigniew Kaczmarczyk ◽

Krzysztof Bodzek

Keyword(s):

Wireless Power Transfer ◽

Maximum Efficiency ◽

Power Transfer ◽

Wireless Power ◽

Tracking Method ◽

Point Tracking

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Dual-Band RF Wireless Power Transfer System with a Shared-Aperture Dual-Band Tx Array Antenna

Energies ◽

10.3390/en14133803 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3803

Author(s):

Chan-Mi Song ◽

Hong-Jun Lim ◽

Son Trinh-Van ◽

Kang-Yoon Lee ◽

Youngoo Yang ◽

...

Keyword(s):

Wireless Power Transfer ◽

Transmission Efficiency ◽

Array Antenna ◽

Dual Band ◽

Single Frequency ◽

Power Transfer ◽

Wireless Power ◽

Beam Focusing ◽

Received Power ◽

Rf Wireless

In this paper, a dual-band RF wireless power transfer (WPT) system with a shared-aperture dual-band Tx array antenna for 2.4 and 5.8 GHz is proposed. The final configuration of the Tx array, which is made up of 2.4 GHz right-handed circular polarization (RHCP) patches and 5.8 GHz RHCP patches, is derived from the optimization of 2.4 and 5.8 GHz thinned arrays, ultimately to achieve high transmission efficiency for various WPT scenarios. The dual-band RF WPT Tx system including the Tx array antenna and a Tx module is implemented, and Rx antennas with a 2.4 GHz patch, a 5.8 GHz patch, and a dual-band (2.4 and 5.8 GHz) patch are developed. To validate the proposed dual-band RF WPT system, WPT experiments using a single band and dual bands were conducted. When transmitting RF wireless power on a single frequency (either 2.482 GHz or 5.73 GHz), the received power according to the distance between the Tx and Rx and the position of the Rx was measured. When the distance was varied from 1 m to 3.9 m and the transmitted power was 40 dBm, the received power value at 2.482 GHz and 5.73 GHz were measured and found to be 24.75–13.5 dBm (WPT efficiency = 2.985–0.224%) and 19.25–6.8 dBm (WPT efficiency = 0.841–0.050%), respectively. The measured results were in good agreement with the calculated results, and it is revealed that the transmission efficiency when wireless power is transmitted via beam-focusing increases more than that with conventional beam-forming. Furthermore, the dual-band WPT experiment proves that 2.482 GHz beam and 5.73 GHz beams can be formed individually and that their wireless power can be transmitted to a dual-band Rx or two different Rx.

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