WiPASS project was aimed at developing an innovative and disruptive Wireless Power Transfer (WPT) technology exploiting a low-frequency variable magnetic field to send electric power over the air between an emitter and receivers based on an electromechanical system. This power is then used to supply electronic functions such as sensors and actuators, with various applications including health, industry, home automation,….
Compared to other WPT technologies, the one proposed in WiPASS operates at very lower frequencies enabling to reach higher transmission distances with better penetration in conductive media.
The Researcher, Nicolas Garraud, developed first Proofs of Concept of this technology during his PhD thesis at the University of Florida. WiPass was aimed at further developing and optimizing this technology, to solve its limitations and to study its commercial relevance. The Research was carried out in CEA-LETI (France) under the supervision of Sebastien Boisseau.
The specificity of the magnetodynamic WPT technology is its low frequency of operation, which is typically less than 1 kHz and with the following advantages:
• They are safe around humans and in presence of metallic objects, allowing transfer in everyday environments,
• Wireless Power Transfer is possible through conducting media, allowing transfer in isolated environments.
Low-frequency time-varying magnetic fields dissipate very little energy in human tissues, allowing higher field amplitude than for their high-frequency counterparts. This makes low-frequency WPT suitable for safely charging wearables or biomedical implants for instance.
Moreover, low-frequency fields create very low Eddy currents and dissipate limited energy in metallic objects, contrary to high-frequency solutions. This eliminates the risk of fire hazard found in high-frequency technologies such as the ones using the Qi protocol requiring the system to stop if nearby conducting objects are detected. Also, low-frequency magnetic fields are less impeded by conductive media, which is suitable for charging systems through metal walls or in seawater.
Finally, low-frequency WPT technologies create very few electromagnetic interferences, which is an advantage for critical systems.
The overall objectives of WiPass project were to:
• Improve the WPT distance by using advanced models in mechanics and electromagnetism (Finite Elements) and by developing innovative mechanical (nonlinear springs) and electromagnetic (iron cores) architectures. The target is a range of 50cm-1 m, with a transmitter sending powers in agreement with European Union norms.
• Develop an efficient Power Management Circuit to supply sensors, microcontrollers and RF protocols from received power and a validation of the complete Electrodynamic Wireless Power Transfer chain.
• Analyze the strengths and opportunities (SWOT) with regards to the state of the art and the industrial pre-feasibility analysis (cost / market).
