Variable Frequency Inverter with Frequency Tracking Control for Ultrasonic Power Transfer across Metal Barriers

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dc.contributor.advisor Hu, AP en Moraes, Kevin en 2018-06-21T00:29:50Z en 2018 en
dc.identifier.uri en
dc.description Full text is available to authenticated members of The University of Auckland only. en
dc.description.abstract In applications that require power transfer across metal barriers, traditionally a wired connection that physically penetrates the metal is used. However, in applications where a wired connection is not convenient or impossible, an emerging wireless power technique called Ultrasonic Power Transfer (UPT) is developed, which transfers power through mechanical vibrations. While the transmission of power across metal barriers has been extensively validated in academic literature, there is a significant lack of power converter development for Loose Contact UPT systems. Currently, theoretical models cannot accurately determine the optimal operating frequency of the Loose Contact UPT system that corresponds to maximum power transfer. In this thesis an empirical approach to guide practical development of Loose Contact UPT systems for optimal frequency tracking is proposed. The measured input admittances of the UPT system is used to characterise the variation in resonant frequencies which can guide the primary power converter and system control design. A practical Loose Contact UPT system is developed using 28 kHz piezoelectric transducers attached to aluminium plates and several Loose Contact setups at varying contact levels are proposed. The effect of loading on the resonant frequencies of the UPT system is investigated for each Loose Contact setup under open and short circuit secondary conditions. A resonant push-pull inverter which operates under zero voltage switching (ZVS) is developed for the primary converter. A switched capacitor network that can vary the operating frequency of the inverter while maintaining ZVS is developed and is improved by using additional capacitor networks for fine tuning the operating frequency of the inverter. To track the optimal operating frequency for maximum power transfer, a frequency sweep method is developed. The operating frequency of the push-pull inverter is varied by coarse tuning of capacitor banks and fine tuning with phase shift control. Experimental results have demonstrated that the proposed frequency sweep controller can accurately track the optimal operating frequency within a range of 26 kHz to 30 kHz under different Loose contact setups and secondary conditions. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof Masters Thesis - University of Auckland en
dc.relation.isreferencedby UoA99265080711502091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights Restricted Item. Available to authenticated members of The University of Auckland. en
dc.rights.uri en
dc.rights.uri en
dc.title Variable Frequency Inverter with Frequency Tracking Control for Ultrasonic Power Transfer across Metal Barriers en
dc.type Thesis en Electrical and Electronic Engineering en The University of Auckland en Masters en
dc.rights.holder Copyright: The author en
pubs.elements-id 745159 en
pubs.record-created-at-source-date 2018-06-21 en

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