Design of a Non-Contact Slip Ring for Power Transfer and Signal Transmission

In the field of aerospace, contact slip ring with brush has the disadvantages of being easy to wear and short-circuit, unreliable signal transmission, etc. To avoid these shortcomings, a new non-contact slip ring is designed for wireless power transfer and signal transmission. Firstly, the slip ring uses the principle of inductive coupling power transfer (ICPT) to transfer the DC power to the secondary side. After analyzing the magnetizing inductance and leakage inductance, the series-parallel capacitor compensation and maximum efficiency control method are applied in the slip ring for the power transfer. Secondly, a non-contact signal transmission method based on capacitive coupling and serial data differential transmission is proposed. The crosstalk between annular capacitor plates is analyzed, and the method to reduce crosstalk is presented. The Manchester encoded is adopted in the digital signal transmission. Finally, a prototype was designed to verify the above methods. When the power is 280W, the maximum efficiency can reach 82%. The transmission method based on capacitive coupling can transmit 1Mbps digital signal. In addition, the transferred power and the frequency of transmitted signal can be further improved. The proposed scheme not only satisfies the requirements of aerospace field, but also has generality for other power transfer and signal transmission methods based on inductive and capacitive coupling.