A Reconfigurable Detuned S-LCC Compensated IPT System with Two Discrete Frequencies for Stable Power Against Coupling Variations

For an inductive power transfer (IPT) system， stable power transfer is one of the most crucial abilities， but coupling variations can dramatically affect the system’s output. This article proposes a reconfigurable detuned S-LCC compensated IPT system with two discrete frequencies to mitigate power fluctuations due to coupling variations. The original detuned S-LCC topology can operate in one stable region. With the change of the primary capacitor and frequency, the equivalent ac load can be altered, which will create a new stable region. Therefore, the expected coupling range of the detuned S-LCC topology can be extended. First, a detuned S-LCC IPT system with two discrete frequencies is presented, followed by an analysis of the working modes. Then, a detailed parameter design process and switching control are introduced. Finally, a 140-W prototype was constructed to verify the validity of the proposed method. The experimental results demonstrate that the output power fluctuation of the proposed IPT system is less than 5% and the lowest efficiency can be improved from 91.5%% to 94%, with the coupling coefficient varying from 0.27 to 0.63. The proposed method does not need complicated control or dedicated coil design, and it can implement stable power transfer significantly.