Robustness of Wireless Power Transfer Systems with Parity-Time Symmetry and Asymmetry

Recently, wireless power transfer (WPT) technology has attracted much attention and shown rapid development. However, a fundamental challenge emerges in practical applications: how to achieve robust power transfer against the variation of operating conditions, such as the fluctuation of transfer dis...

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Main Authors: Haiyan Zhang, Kejia Zhu, Zhiwei Guo, Yuguang Chen, Yong Sun, Jun Jiang, Yunhui Li, Zhuoping Yu, Hong Chen
Format: Article
Language:English
Published: MDPI AG 2023-06-01
Series:Energies
Subjects:
Online Access:https://www.mdpi.com/1996-1073/16/12/4605
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author Haiyan Zhang
Kejia Zhu
Zhiwei Guo
Yuguang Chen
Yong Sun
Jun Jiang
Yunhui Li
Zhuoping Yu
Hong Chen
author_facet Haiyan Zhang
Kejia Zhu
Zhiwei Guo
Yuguang Chen
Yong Sun
Jun Jiang
Yunhui Li
Zhuoping Yu
Hong Chen
author_sort Haiyan Zhang
collection DOAJ
description Recently, wireless power transfer (WPT) technology has attracted much attention and shown rapid development. However, a fundamental challenge emerges in practical applications: how to achieve robust power transfer against the variation of operating conditions, such as the fluctuation of transfer distance, as well as the relative orientation of resonant coils. In this article, we theoretically propose and experimentally demonstrate that the robustness of a parity-time (PT) asymmetric system with unbalanced gain-loss working in a weak coupling region can be improved significantly, compared with that of a PT-symmetric system with balanced gain-loss working in a strong coupling region under the premise that the system works at a fixed optimal frequency. A pure real mode known as bound state in the continuum (BIC) in the weak coupling region of the PT-asymmetric system is adopted to ensure the high efficiency and stability of the WPT and break the limitations of balanced gain-loss of the PT-symmetric system. The better robustness performance originates from the orthogonal state with a pure real eigenmode embedded in the weak coupling region. Further experiments also verify that the PT-asymmetric system can achieve higher efficiency than that of the PT-symmetric system. In addition, we discuss the performance of the WPT system based on the theories of coupled mode theory (CMT) and circuit theory (CT); the BIC in the framework of CMT and a perfect impedance matching condition in the framework of CT for efficient power transfer are consistent. We also conducted power experimental verification of 30 watts, and found the efficiency between the coils can reach over 90% in dynamic scenarios, which meets expectations. The presented framework extends the field of non-Hermitian physics, bridges the gap between the non-ideal PT-symmetric system and a practical engineering application, and introduces a novel WPT mechanism for flexible application scenarios. Our results could provide instructive significance for practical applications of the WPT system in the long term.
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spelling doaj.art-d97fc1944d1f4cdca753962a5c3a79f92023-11-18T10:11:39ZengMDPI AGEnergies1996-10732023-06-011612460510.3390/en16124605Robustness of Wireless Power Transfer Systems with Parity-Time Symmetry and AsymmetryHaiyan Zhang0Kejia Zhu1Zhiwei Guo2Yuguang Chen3Yong Sun4Jun Jiang5Yunhui Li6Zhuoping Yu7Hong Chen8School of Physics Science and Engineering, Tongji University, Shanghai 200092, ChinaDepartment of Electrical Engineering, Tongji University, Shanghai 201804, ChinaSchool of Physics Science and Engineering, Tongji University, Shanghai 200092, ChinaSchool of Physics Science and Engineering, Tongji University, Shanghai 200092, ChinaSchool of Physics Science and Engineering, Tongji University, Shanghai 200092, ChinaPostdoctoral Station of Mechanical Engineering, Tongji University, Shanghai 200092, ChinaSchool of Physics Science and Engineering, Tongji University, Shanghai 200092, ChinaCollege of Automotive Studies, Tongji University, Shanghai 201804, ChinaSchool of Physics Science and Engineering, Tongji University, Shanghai 200092, ChinaRecently, wireless power transfer (WPT) technology has attracted much attention and shown rapid development. However, a fundamental challenge emerges in practical applications: how to achieve robust power transfer against the variation of operating conditions, such as the fluctuation of transfer distance, as well as the relative orientation of resonant coils. In this article, we theoretically propose and experimentally demonstrate that the robustness of a parity-time (PT) asymmetric system with unbalanced gain-loss working in a weak coupling region can be improved significantly, compared with that of a PT-symmetric system with balanced gain-loss working in a strong coupling region under the premise that the system works at a fixed optimal frequency. A pure real mode known as bound state in the continuum (BIC) in the weak coupling region of the PT-asymmetric system is adopted to ensure the high efficiency and stability of the WPT and break the limitations of balanced gain-loss of the PT-symmetric system. The better robustness performance originates from the orthogonal state with a pure real eigenmode embedded in the weak coupling region. Further experiments also verify that the PT-asymmetric system can achieve higher efficiency than that of the PT-symmetric system. In addition, we discuss the performance of the WPT system based on the theories of coupled mode theory (CMT) and circuit theory (CT); the BIC in the framework of CMT and a perfect impedance matching condition in the framework of CT for efficient power transfer are consistent. We also conducted power experimental verification of 30 watts, and found the efficiency between the coils can reach over 90% in dynamic scenarios, which meets expectations. The presented framework extends the field of non-Hermitian physics, bridges the gap between the non-ideal PT-symmetric system and a practical engineering application, and introduces a novel WPT mechanism for flexible application scenarios. Our results could provide instructive significance for practical applications of the WPT system in the long term.https://www.mdpi.com/1996-1073/16/12/4605non-Hermitian physicsbound state in the continuumwireless power transferrobustness
spellingShingle Haiyan Zhang
Kejia Zhu
Zhiwei Guo
Yuguang Chen
Yong Sun
Jun Jiang
Yunhui Li
Zhuoping Yu
Hong Chen
Robustness of Wireless Power Transfer Systems with Parity-Time Symmetry and Asymmetry
Energies
non-Hermitian physics
bound state in the continuum
wireless power transfer
robustness
title Robustness of Wireless Power Transfer Systems with Parity-Time Symmetry and Asymmetry
title_full Robustness of Wireless Power Transfer Systems with Parity-Time Symmetry and Asymmetry
title_fullStr Robustness of Wireless Power Transfer Systems with Parity-Time Symmetry and Asymmetry
title_full_unstemmed Robustness of Wireless Power Transfer Systems with Parity-Time Symmetry and Asymmetry
title_short Robustness of Wireless Power Transfer Systems with Parity-Time Symmetry and Asymmetry
title_sort robustness of wireless power transfer systems with parity time symmetry and asymmetry
topic non-Hermitian physics
bound state in the continuum
wireless power transfer
robustness
url https://www.mdpi.com/1996-1073/16/12/4605
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