1kW Contactless Slip Ring Design Using Series-Series Resonant Converter Topology

Polat, Hakan
Slip rings are often used in wound rotor synchronous machines to supply required field excitation during rotation. They mainly consist of carbon brushes and copper rings where the power transmission is achieved by constant friction, which results in mechanical wear over time. To eliminate the contact, brushless exciters are used. However, their low-speed operation is problematic. Therefore, in this thesis, the aim is to design a contactless slip-ring with improved fault tolerance to supply the required field current without physical contact and with a wide speed range limited solely by mechanical limitations. To achieve high reliability, modular design is employed. The power transfer is achieved by two transmitters and four receivers whose outputs are connected in parallel to form a common DC-bus. The system is series-series compensated. The problem of current/power-sharing is solved first analytically with the introduction of cross-coupling and intentional detuning. Then a 1 kW system is designed to experimentally verify the proposed methods. While an increased power-sharing is observed, to further increase the fault tolerance, a middle-stage resonator is added, and an experimental setup is built. Finally, the presented system is mounted on a rotating shaft, and improved fault tolerance compared to conventional single transmitter single receiver inductive power transfer systems is achieved.
Citation Formats
H. Polat, “1kW Contactless Slip Ring Design Using Series-Series Resonant Converter Topology,” M.S. - Master of Science, Middle East Technical University, 2021.