TY - GEN
T1 - A Litz-Wire Based Passive Shield Design to limit EMF Emission from Wireless Charging System
AU - Mohammad, Mostak
AU - Haque, Moinul Shahidul
AU - Choi, Seungdeog
N1 - Publisher Copyright:
© 2018 IEEE.
PY - 2018/12/3
Y1 - 2018/12/3
N2 - In this paper, a litz wire based passive shield design is proposed which shows the ability to suppress the electromagnetic field (EMF) emission below the limit set by International Commission on Non-Ionizing Radiation Protection (ICNIRP) and also minimize the shield loss. Traditionally passive aluminum plate or active anti-turn has been used in EMF suppressing shield design. However, these designs show limited controllability of the shield current. Moreover, the high-frequency eddy current loss in the passive aluminum plate is approximately 0.4% and it can increase more than 2.0% at low coupling operation under misalignment. The shield current and associated shield loss are highly localized around the outer boundary of the shield in a unipolar pad. Therefore, it can be optimized effectively with passive litz wire turn at the outer boundary of the traditional aluminum shield. In this paper, a shield design is proposed with a thin aluminum plate and a passive litz-wire-loop around the outer radius of the pad. The result shows that approximately 80% of the shield current is induced in the newly added litz-wire-loop and results in a greater controllability on the shield current and EMF suppression. The litz wire mitigates the high-frequency skin effect and significantly reduces the shield resistance. In this paper, this advantage is applied in shield design for EMF suppression using a passive litz-wire loop. This method is also effective for shield loss minimization. Moreover, the proposed design provides a highly effective and efficient shielding for a high-power loosely coupled system.
AB - In this paper, a litz wire based passive shield design is proposed which shows the ability to suppress the electromagnetic field (EMF) emission below the limit set by International Commission on Non-Ionizing Radiation Protection (ICNIRP) and also minimize the shield loss. Traditionally passive aluminum plate or active anti-turn has been used in EMF suppressing shield design. However, these designs show limited controllability of the shield current. Moreover, the high-frequency eddy current loss in the passive aluminum plate is approximately 0.4% and it can increase more than 2.0% at low coupling operation under misalignment. The shield current and associated shield loss are highly localized around the outer boundary of the shield in a unipolar pad. Therefore, it can be optimized effectively with passive litz wire turn at the outer boundary of the traditional aluminum shield. In this paper, a shield design is proposed with a thin aluminum plate and a passive litz-wire-loop around the outer radius of the pad. The result shows that approximately 80% of the shield current is induced in the newly added litz-wire-loop and results in a greater controllability on the shield current and EMF suppression. The litz wire mitigates the high-frequency skin effect and significantly reduces the shield resistance. In this paper, this advantage is applied in shield design for EMF suppression using a passive litz-wire loop. This method is also effective for shield loss minimization. Moreover, the proposed design provides a highly effective and efficient shielding for a high-power loosely coupled system.
KW - EMF suppression
KW - Litz-wire
KW - Shield loss
UR - http://www.scopus.com/inward/record.url?scp=85060271247&partnerID=8YFLogxK
U2 - 10.1109/ECCE.2018.8558334
DO - 10.1109/ECCE.2018.8558334
M3 - Conference contribution
AN - SCOPUS:85060271247
T3 - 2018 IEEE Energy Conversion Congress and Exposition, ECCE 2018
SP - 97
EP - 104
BT - 2018 IEEE Energy Conversion Congress and Exposition, ECCE 2018
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 10th Annual IEEE Energy Conversion Congress and Exposition, ECCE 2018
Y2 - 23 September 2018 through 27 September 2018
ER -