491 / 2022-03-17 20:55:36

Electric Field Analysis and Insulation Design of Wireless Power Transfer Coils Under High-Voltage Stress

Wireless Power Transfer Coils,Electric Field,High-Voltage

Purpose/Aim

The employment of wireless power transfer (WPT) in supplying power for high-voltage SiC devices’ gate drives starts WPT’s application under high voltage. This paper analyses the E-field around the coils under some working conditions through simulation software, aiming at guiding high galvanic isolation design.

Experimental/Modeling methods

Analysis is conducted in Ansys Electronic Desktop, mainly using Maxwell 2D&3D and Simplore.

Results/discussion

The maximum of the E-fields (40.26 kV/cm) appears at the edge of the outer sides of transmitter and receiver coils when a 50 kV high voltage is exerting at the receiver side with a 10 cm distance between the two coils, and its value declines when the radius of the coils rises or the distance between the coils increases. The employment of ferrite shielding layer will reduce the value of Emax in certain situation, and an appropriate shielding layer is designed through traversal method, decreasing the value of Emax to 37.45 kV/cm, along with the prominent increase of the mutual inductance between the coils and subtle rise of parasitic capacitance.

Conclusions

The decline of the value of Emax can be realized by increasing the radius of the coils or rising the distance between the coils. Ferrite shielding layer, if designed properly, can improve coils’ resistance to high voltage.