{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,2]],"date-time":"2026-07-02T19:25:27Z","timestamp":1783020327139,"version":"3.54.6"},"reference-count":15,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2021,3,10]],"date-time":"2021-03-10T00:00:00Z","timestamp":1615334400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["NRF-2019R1F1A1062892"],"award-info":[{"award-number":["NRF-2019R1F1A1062892"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["NRF-2017R1E1A1A03070882"],"award-info":[{"award-number":["NRF-2017R1E1A1A03070882"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>The improvement of power transmission efficiency (PTE) is an important issue in the design of a wireless power transfer (WPT) system. The WPT system with multiple transmitting (Tx) or receiving (Rx) coils is a way to improve the PTE. This paper deals with the estimation of the mutual inductance angle for a two-dimensional (2D) WPT system with two Tx coils and one Rx coil. The mutual inductance angle is one of the most important parameters to determine the PTE in the 2D WPT system. The condition for the maximum PTE is investigated and the mutual inductance angle is defined for the 2D WPT system. An improved estimation method of the mutual inductance angle is proposed based on the phase-locked loop (PLL) technique using the voltages and currents of the Tx coils. The simulation and experimental results are provided to validate the effectiveness of the proposed method.<\/jats:p>","DOI":"10.3390\/sym13030448","type":"journal-article","created":{"date-parts":[[2021,3,10]],"date-time":"2021-03-10T20:51:42Z","timestamp":1615409502000},"page":"448","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["An Improved Estimation Method of Mutual Inductance Angle for a Two-Dimensional Wireless Power Transfer System"],"prefix":"10.3390","volume":"13","author":[{"given":"Sangyong","family":"Lee","sequence":"first","affiliation":[{"name":"Department of Electrical and Electronic Engineering, Gyeongsang National University, 501 Jinjudaero, Jinju, Gyeongnam 52828, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jeonho","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronic Engineering, Gyeongsang National University, 501 Jinjudaero, Jinju, Gyeongnam 52828, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jongkyum","family":"Kwon","sequence":"additional","affiliation":[{"name":"Department of Mathematics Education, Gyeongsang National University, 501 Jinjudaero, Jinju, Gyeongnam 52828, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Se-Kyo","family":"Chung","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronic Engineering, Gyeongsang National University, 501 Jinjudaero, Jinju, Gyeongnam 52828, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"4470","DOI":"10.1109\/TPEL.2014.2300866","article-title":"Two- and Three-Dimensional Omnidirectional Wireless Power Transfer","volume":"29","author":"Ng","year":"2014","journal-title":"IEEE Trans. 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[3rd ed.].","DOI":"10.1002\/0471732699"}],"container-title":["Symmetry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-8994\/13\/3\/448\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:35:50Z","timestamp":1760160950000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-8994\/13\/3\/448"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,3,10]]},"references-count":15,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2021,3]]}},"alternative-id":["sym13030448"],"URL":"https:\/\/doi.org\/10.3390\/sym13030448","relation":{},"ISSN":["2073-8994"],"issn-type":[{"value":"2073-8994","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,3,10]]}}}