MOSFET-based H-bridge Inverter for Wirelessly Charging Implantable Medical Devices

Researchers are working relentlessly to design an efficient and safe wireless power transfer technique to charge biomedical implants by combining a suitable coupling method with a high-frequency inverter that can transfer ultra-low power to biomedical implants rapidly and at a lower cost. The H-bridge inverter is a multi-level inverter, which provides a sinusoidal output voltage. Furthermore, the H-bridge inverter produces a staircase output waveform with fewer harmonics in comparison with the output voltage of other conventional inverters. While designing an inverter, it is crucial to use minimal switches, reduce switching losses, and ensure more controllability and switching flexibility with high precision, while also achieving a high power transfer efficiency. H-bridge inverters have been used in several applications including power inverters for solar photovoltaic systems, grid-connected inverters for wind energy conversion systems, variable frequency inverters for induction motor drives, and inductive power transfer technology to charge electric vehicles. However, the use of an H-bridge inverter is rather limited in biomedical implants because of its large size and high conduction losses. In this work, we have designed a MOSFET-based H-bridge inverter that is portable, provides low switching and conduction losses, switching flexibility with high precision, high operating frequency, and low output power, which are desirable features for wirelessly charging implantable devices for brain and liver, namely deep brain stimulator and insulin pump.