Output Voltage Identification Based on Transmitting Side Information for Implantable Wireless Power Transfer System

Wireless power transfer (WPT) offers a promising solution to power implantable medical devices (IMDs). Due to the variations of mutual inductance and load, the output voltage of the implantable WPT system is easily unstable. To maintain a constant voltage for IMDs’ operation, a novel method to identify the output voltage of the WPT system without any direct measurement on the receiving side is presented in this paper, where only the input voltage and current need to be measured. First, the output voltage identification of the WPT system is applied to the classic series–parallel compensation network. Next, an improved WPT system with S-LCL compensation network is proposed, which has the advantage that the output voltage identification is independent of mutual inductance and load resistance. Moreover, the characteristic analysis of the proposed WPT system is carried out, which proves its performance of high transfer efficiency. Finally, the WPT prototype with the S-LCL compensation network is built and tested. The experimental results are provided to further verify the correctness of theoretical analysis.