VP3-09 Three phase transmitting coil for leakage magnetic field reduction in wireless power transfer
Creators: Dong-Min Kim
Jeonghyeon Cheon
Heegeon Park
and Dongwook Kim
Publisher: name: IEEE
Year: 2025

Wireless power transfer technology has been widely used based on convenience and safety. Specifically, various technologies for transmitting power in a situation that the receiving (Rx) coil moves along the transmitting (Tx) coil has been actively studied. In these systems, a long Tx coil is embedded to the road and high power is transmitted to the Rx coil. Consequently, a large amount of leakage magnetic field is generated around the Tx coil due to strong electromagnetic field [1]. Reducing the leakage magnetic field is very important because it can significantly affect not only human body but also surrounding electronic devices [2], [3]. In this paper, a three phase Tx coil structure is proposed to reduce the leakage magnetic field as illustrated in Fig. 1. Through the simulation, the leakage magnetic field is compared for the conventional and proposed Tx coil structures at the observation assuming the center of Tx coil as the origin, and magnetic field distribution is compared at the center of Tx coil. Also, a certain Rx coil is added to compare the induced voltage when the Rx coil is in the -900 mm to 900 mm position respect to the center of Tx coil. Simulation results represent that the proposed type B has the smallest leakage magnetic field as depicted in Fig. 2(a). Compared to the single phase coil, magnetic field decreased by about 82.5% at the observation point. In addition, the magnetic field distribution has decreased compared to the rest of the structures as illustrated in Fig. 2(b). The average induced voltage generated in Rx coil is 2.297 V, 0.391 V, 1.160 V, and 1.079 V in single phase, meander type, proposed type A, and proposed type B, respectively. The proposed type B has average induced voltage value of about 46.9% for the single phase, and it is verified that this value is appropriate compared to the amount of leakage magnetic field reduction.References: [1] M. Kim et al., “A Three Phase Wireless Power Transfer System for Online Electric Vehicles with Reduction of Leakage Magnetic Fields,” IEEE Transactions on Microwave Theory and Techniques, Vol. 63, No. 11, Nov., 2015. [2] S. Kim et al., “Design and Analysis of a Resonant Reactive Shield for a Wireless Power Electric Vehicle,” IEEE Transactions on Microwave Theory and Techniques, Vol. 62, No. 4, Apr., 2014. [3] H. Moon et al., “Design of a Resonant Reactive Shield With Double Coils and a Phase Shifter for Wireless Charging of Electric Vehicles,” IEEE Transactions on Magnetics, Vol. 51, No. 3, Mar., 2015.
Wireless power transfer technology has been widely used based on convenience and safety. Specifically, various technologies for transmitting power in a situation that the receiving (Rx) coil moves along the transmitting (Tx) coil has been actively studied. In these systems, a long Tx coil is embedded to the road and high power is transmitted to the Rx coil. Consequently, a large amount of leakage magnetic field is generated around the Tx coil due to strong electromagnetic field [1]. Reducing the leakage magnetic field is very important because it can significantly affect not only human body but also surrounding electronic devices [2], [3]. In this paper, a three phase Tx coil structure is proposed to reduce the leakage magnetic field as illustrated in Fig. 1. Through the simulation, the leakage magnetic field is compared for the conventional and proposed Tx coil structures at the observation assuming the center of Tx coil as the origin, and magnetic field distribution is compared at the center of Tx coil. Also, a certain Rx coil is added to compare the induced voltage when the Rx coil is in the -900 mm to 900 mm position respect to the center of Tx coil. Simulation results represent that the proposed type B has the smallest leakage magnetic field as depicted in Fig. 2(a). Compared to the single phase coil, magnetic field decreased by about 82.5% at the observation point. In addition, the magnetic field distribution has decreased compared to the rest of the structures as illustrated in Fig. 2(b). The average induced voltage generated in Rx coil is 2.297 V, 0.391 V, 1.160 V, and 1.079 V in single phase, meander type, proposed type A, and proposed type B, respectively. The proposed type B has average induced voltage value of about 46.9% for the single phase, and it is verified that this value is appropriate compared to the amount of leakage magnetic field reduction.References: [1] M. Kim et al., “A Three Phase Wireless Power Transfer System for Online Electric Vehicles with Reduction of Leakage Magnetic Fields,” IEEE Transactions on Microwave Theory and Techniques, Vol. 63, No. 11, Nov., 2015. [2] S. Kim et al., “Design and Analysis of a Resonant Reactive Shield for a Wireless Power Electric Vehicle,” IEEE Transactions on Microwave Theory and Techniques, Vol. 62, No. 4, Apr., 2014. [3] H. Moon et al., “Design of a Resonant Reactive Shield With Double Coils and a Phase Shifter for Wireless Charging of Electric Vehicles,” IEEE Transactions on Magnetics, Vol. 51, No. 3, Mar., 2015.