Living object detection in wireless power transfer systems using remote capacitive bio-signals monitoring

Living object detection (LOD) in the context of wireless power transfer (WPT) systems can help mitigate the health risks associated with the presence of people and animals in the vicinity of high intensity magnetic fields, while assisting in the management of WPT operation in face of unforeseen link performances due to the presence of foreign objects. In this paper, we propose custom-built capacitive sensors that can detect the bio-signals for heartbeat and respiration from the body of an individual and capacitively coupled to the detection electronics during WPT operation. Performance metrics such as bio-signal amplitude and frequency content are tested for different current levels in an operating transmission coil and several distance separations from the WPT system. We hope that this study can pave the way towards the implementation of LOD systems operating in tandem with wireless power links to provide valuable feedback for safeguarding the well-being of nearby living objects, which can present high permittivity value contrasts for the typical operational frequencies in WPT.