BESTMEMS

Ensuring the security of goods and people in transportation is a serious issue. In order to ensure this objective, the use of embedded sensors has been the subject of an exceptional growth over the last few years. However, bringing power supply to a large part of such sensors is still an open issue, as bringing supply wires is not possible for moving parts. In such a case, typical solutions rely on the use of primary batteries, but the latter yields costly maintenance issues because of the self-discharge, which can also raise security problems, as the sensor cannot work without energy. Recently, the concept of “energy harvesting”, consisting of converting an energy source directly available to the system into useful electricity, has become a reliable way for replacing batteries. In particular, many studies were devoted to the conversion of mechanical energy, as such a source is commonly available in many environments (road traffic, machinery, etc…). However, challenges for the integration of the microgenerator at dimensions similar to the electronic device to supply as well as efficient harvesting for real-life, complex mechanical excitations still hold. Tackling these issues requires, in addition to the development of cutting-edge technologies, a perfect mastering of the transdisciplinary fields involved in the design of the harvester, going from the material aspects to the electrical domain through mechanical considerations. Furthermore, a perfect knowledge of the interfaces between these domains and multiphysic couplings is necessary for the disposal of efficient microgenerators. BESTMEMS hence proposes to provide such an approach that consists of conceiving the harvesting system as a whole instead of seeing the device as a simple association of independent blocks which would lead to a sub-optimized system. The project is furthermore driven by applications in the fields of transportations, through the development of Tyre Pressure Monitoring Sensor (TPMS) and smart bearings. The project encompasses partners with worldwide recognized expertise in the fields of material elaboration, mechanics, electromechanical coupling and electronics, along with two partners from industries (one for each country) that will help in developing a realistic global device. This will therefore permits developing efficient and optimized microgenerators, with particular focuses on the following issues: 1. Development of a MEMS (Micro-ElectroMechanical System) transducer for mechanical to electrical energy conversion; 2. Optimization (in a global way) of the mechanical coupling between the transducer, the substrate and the electronic interface for harvesting; 3. Optimization (in a global way) of the electrical interface for energy extraction; in particular, integrated nonlinear treatment interfaces for energy conversion enhancement will be developed in the particular case of MEMS system. 4. Device optimization with respect to the target application; exploitation of mechanical and electrical nonlinearities (as well as the coupling between them) for broadband energy harvesting is a key issue to dispose of efficient harvesting systems. 5. Optimization of the power management strategy and development of integrated power management module; 6. Design of self-powered devices for transportation systems (Tyre Pressure Monitoring System and smart bearings) Project name: BESTMEMS (Broadband Energy Scavenging Technologies for Micro Electro-Mechanical Systems) Partners: LGEF INSA (France), NTU (Taiwan), LTDS ECL (France), NTHU (Taiwan), SIMTRANS (Taiwan), SKF (France) Budget (ANR) : 313 000 € (533 180 € total) Keywords: Energy harvesting, self-powered devices, multiphysic coupling, MEMS, power management and sensors, nonlinearities, nonlinear mechanics Start date: November 2015 End date: November 2018