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Dadashzadeh, Hoda

University of British Columbia

Wireless Power Transfer (WPT) system has the advantage of delivering power through a medium without using physical conductors to make an electrical connection. Two categories of WPT systems are Inductive Power Transfer (IPT) and Capacitive Power Transfer (CPT). In this thesis, the focus is on CPT. The work is motivated by challenges associated with obtaining efficient power transfer over relatively large gaps ranging from a few centimeters up to 20 cm. A dual-band CPT system is proposed that operates at frequencies of 13.56 MHz and 27.12 MHz. Depending on the gap distance, a specific frequency is selected. The primary focus in this research is the design of the high efficiency power amplifiers and rectifiers that are required to implement the dual-band system. The class-E circuit topology is selected for the designs. The theory of time-reversal duality is applied to convert the power amplifier circuits into synchronous rectifier circuits. The rectifier converts the Radio Frequency (RF) power to DC power and the rectification efficiency depends on load resistance. A variable load circuit board is implemented using a DC-DC power converter to track the maximum power efficiency of the rectifier. A buck converter is selected for the design and duty cycle is used to change the input resistance of the converter. In the last part of this work, the power amplifiers and the rectifiers are connected to a capacitive coupling network with an adjustable load resistance. The power and efficiency of the CPT system is simulated for gap distances ranging from 5 cm to 20 cm. Simulation results show that for maintaining high efficiency operation of the CPT the system, it needs to operate at 27.12 MHz for small gap separations and the frequency is switched to 13.56 MHz for larger gap separations.

Text

2022-02-18

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/80858

Electrical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/