Extending the Operation Range of Wireless Power Supply for Heart Pumps

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dc.contributor.advisor Hu, A en
dc.contributor.advisor Budgett, D en
dc.contributor.author Wang, Bob en
dc.date.accessioned 2014-01-28T03:20:31Z en
dc.date.issued 2013 en
dc.identifier.uri http://hdl.handle.net/2292/21477 en
dc.description.abstract Heart disease is a serious and costly medical problem. Because of a lack of heart donors, heart pumps are increasingly deployed. Current pumps are powered by percutaneous drivelines across the skin, which impose infection risks. Transcutaneous energy transfer (TET) can be used to transfer power across the skin without direct wire connection. However the existing TET systems have very limited operation range that constrains the patient movements and comfort and can be worsened by tissue regrowth after implantation. This research is about extending the operation range of wireless powered heart pumps. This involves investigation of the system frequency bifurcation phenomenon, development of primary side power flow controllers, secondary side synchronous rectifiers, and power flow controllers. Firstly, a theoretical study of the frequency bifurcation phenomenon and the dynamic waveform transition is conducted. It is found that bifurcation can greatly reduce the system maximum power transfer capability if simple zero voltage switching (ZVS) control strategy is employed, and the system has a single maximum power point corresponding to the middle ZVS frequency even under bifurcation. Next, two primary side power flow controllers are proposed to extend the system operation range with larger coupling tolerance. The first one employs a slow feedback loop with an upper frequency boundary, and has achieved coil separation up to 10mm. The other extends the coil separation range to 24mm by having an automatic ZVS range to keep the system close to the lower ZVS branch. Thirdly, a middle frequency ZVS controller is proposed to maximise the power transfer capability upon system bifurcation while maintaining ZVS operation. This allows the system to transfer the rated power at a lower input voltage, a greater coil coupling tolerance, and improved end-to-end efficiency. Lastly, a synchronous rectifier with two drive options has been developed to reduce power losses and further improve the operation range. Also, load regulation is enabled by controlling the resonant shorting period, allowing a regulated coil separation of up to 9mm. This can be extended to 27mm with combined primary side control. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof PhD Thesis - University of Auckland 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.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.rights.uri http://creativecommons.org/licenses/by-nc-sa/3.0/nz/ en
dc.title Extending the Operation Range of Wireless Power Supply for Heart Pumps en
dc.type Thesis en
thesis.degree.grantor The University of Auckland en
thesis.degree.level Doctoral en
thesis.degree.name PhD en
dc.rights.holder Copyright: The Author en
dc.rights.accessrights http://purl.org/eprint/accessRights/OpenAccess en
pubs.elements-id 424986 en
pubs.record-created-at-source-date 2014-01-28 en

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