TY - JOUR
T1 - The Faraday Shields Loss of Transformers
AU - Shen, Zhan
AU - Kaymak, Murat
AU - Wang, Huai
AU - Hu, Jingxin
AU - Jin, Long
AU - Blaabjerg, Frede
AU - Doncker, Rik W. de
PY - 2020/11
Y1 - 2020/11
N2 - Faraday shields are widely used in high-frequency transformers to conduct the common-mode (CM) current to the ground. They are normally located in the high magnetomotive force (MMF) region, where severe eddy currents are induced and contribute considerable magnetic field losses. In this article, an analytical procedure is presented for the magnetically-induced loss in Faraday shields. It is originally derived from shields of foil conductors. Then, it is extended to different shields with round and Litz wire, and different configurations, e.g., multilayer shields, interleaved windings, and coaxial transformers. It is verified by the finite element method (FEM) and experimental results in six case studies. Moreover, the criteria to determine the losses of Faraday shields is given and a design procedure is presented to reduce the shield losses at a certain level while keeping the functionality. Finally, a case study is provided to verify the shield design procedure on a 100-kHz transformer.
AB - Faraday shields are widely used in high-frequency transformers to conduct the common-mode (CM) current to the ground. They are normally located in the high magnetomotive force (MMF) region, where severe eddy currents are induced and contribute considerable magnetic field losses. In this article, an analytical procedure is presented for the magnetically-induced loss in Faraday shields. It is originally derived from shields of foil conductors. Then, it is extended to different shields with round and Litz wire, and different configurations, e.g., multilayer shields, interleaved windings, and coaxial transformers. It is verified by the finite element method (FEM) and experimental results in six case studies. Moreover, the criteria to determine the losses of Faraday shields is given and a design procedure is presented to reduce the shield losses at a certain level while keeping the functionality. Finally, a case study is provided to verify the shield design procedure on a 100-kHz transformer.
KW - Common-mode (CM) current
KW - eddy current
KW - faraday shield
KW - isolation transformer
KW - winding losses
UR - http://www.scopus.com/inward/record.url?scp=85089310772&partnerID=8YFLogxK
U2 - 10.1109/TPEL.2020.2982447
DO - 10.1109/TPEL.2020.2982447
M3 - Journal article
SN - 0885-8993
VL - 35
SP - 12194
EP - 12206
JO - I E E E Transactions on Power Electronics
JF - I E E E Transactions on Power Electronics
IS - 11
M1 - 9044420
ER -