Resonant topology design method for implantable wireless power transfer system

Abstract

The variable load and coil distance of implantable wireless power transfer system lead to unsteady output voltage, and resonant topology for wireless power transfer system is likely to solve this issue. But existing topologies are unable to meet the demands of implantable wireless power transfer system in practice. This paper presented a method to design resonant topologies for implantable wireless power transfer system in detail and proposed a series of topologies. Wireless power transfer systems based on the proposed topologies can achieve load‐independent output voltage. The output voltage is not constrained by the parameter of coils and its load‐independent feature is irrelevant to the coupling coefficient. Besides, a simple output voltage estimation method can be implemented on the transmitting side to monitor output voltage accurately. The characteristics of proposed implantable wireless power transfer systems are compared and the most attractive resonant topology named LCC/PS topology is pointed out. The proposed implantable LCC/PS wireless power transfer system has high power transfer efficiency from 60% to 76.9% at a coil distance of 5 cm when the load varies from 500 to 2500 Ω. An experimental setup is built and its working frequency is 6.78 MHz. The experimental results with acceptable tolerance show the accuracy of theoretical analysis and the excellent performance of the resonant topologies.

Physics-Based Modeling of Ferroelectric Hysteresis for Ceramic Capacitors in Inductively Coupled Microstimulators

“…The amplitude of the stimulation current is controlled by IPT using open-loop control methods. Unlike active control approaches, passive control methods employ compensation circuits to optimize the transfer function of the IPT [22]. To reduce the number of components needed to regulate the voltage on the receiver side and thus reduce the volume of the implantable electronics, the authors in [22] proposed an LCC/PS compensation circuit to design an IPT system with a loadindependent output voltage at a frequency of 6.78 MHz.…”

“…Unlike active control approaches, passive control methods employ compensation circuits to optimize the transfer function of the IPT [22]. To reduce the number of components needed to regulate the voltage on the receiver side and thus reduce the volume of the implantable electronics, the authors in [22] proposed an LCC/PS compensation circuit to design an IPT system with a loadindependent output voltage at a frequency of 6.78 MHz. At a constant inductive coupling factor, the voltage could be kept within a range of roughly 4.6 V to 4.9 V among a load range of 500 Ω to 2500 Ω [22].…”

“…To reduce the number of components needed to regulate the voltage on the receiver side and thus reduce the volume of the implantable electronics, the authors in [22] proposed an LCC/PS compensation circuit to design an IPT system with a loadindependent output voltage at a frequency of 6.78 MHz. At a constant inductive coupling factor, the voltage could be kept within a range of roughly 4.6 V to 4.9 V among a load range of 500 Ω to 2500 Ω [22]. However, if the distance between the two coils changes from 7 cm to 3 cm, the output voltage increases from 3 V to 7.5 V [22].…”

Load‐independent inverse class‐E ZVS inverter and its application to wireless power transfer systems

“…The resonant power converters with mega‐hertz‐order operating frequency have been attracted many researchers and developers [1–9]. High‐frequency operations contribute to small circuit volume, high power density, and lightweights of the converters.…”

Novel compact coupled resonator wireless power transfer system at 1 GHz using nested open loop ring resonators

“…25 The work in Wang et al 26 is improved the power transfer performance, the operating characteristics of a conformal coplanar four-coil magnetic resonant coupling WPT system. The article in Lin et al 27 is presented a resonant topology design method for implantable WPT system, by which a series of WPT topologies are proposed.…”