Rectifier Design for Highly Loaded Inductive Wireless Power Transfer Systems for Biomedical Applications

摘要

Power transfer efficiency (PTE) and harmonics are crucial performance parameters of the resonant rectifier design for low/medium coupling inductive wireless power transfer (WPT) systems used in wireless biomedical implants. The performance of a resonant rectifier degrades under higher loading and lower coupling conditions as the voltage available to the rectifier at the output of the receiver coil becomes low. As the diode turn-on impedance increases, diodes turn on incompletely, leading to non-linearities that reduce rectifier efficiency and output voltage. This work proposes a new rectifier design to increase efficiency and reduce harmonics by decreasing the diode turn-on impedance compared to traditional rectifier designs, such as resonant Half Wave Rectifier (HWR). The proposed rectifier design offers individual paths for RF and rectification signals, which reduces the non-linear loading on the receiver coil and improves diode turn-on performance. Measurement and SPICE simulation results show efficiency enhancement of 50% and reduction of harmonics by 6 dB for the proposed rectifier compared to HWR.