A Resonant Modular Multilevel Rectifier for Secondary Control in Inductive Power Transfer

Secondary control of the inductive-power-transfer (IPT) system can achieve robust output regulation by eliminating the long propagation delay of wireless communication in the feedback control between the transmitter and receiver. Recently, the multilevel switched-capacitor converter has been employed for rectification in the receiver, but experiences high charge sharing loss. In this letter, a resonant modular multilevel rectifier (RMMR) is proposed to eliminate the charge sharing loss in the conventional multilevel rectifier. The proposed RMMR is applied in a series-series compensated IPT system to implement independent secondary control for output voltage regulation with low harmonic distortion and reduced conduction loss. The operating principle is analyzed in detail and a generic analytical expression of the system voltage gain is provided. In addition, the operation of the proposed topology is validated experimentally, and a peak dc-dc efficiency of 96.6% is measured in the experiments.