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International audience; This paper reports a new functional design and modeling of a vibration energy harvester composedfrom a mechanical resonator (MEMS), capacitive transducer and a conditioning circuit based on the BUCK DC-DC converter architecture. The basic configuration of conditioning circuit from [1][2] is enhanced with two majorfeatures for the power management allowing, firstly, to adapt dynamically to the variation of external vibrationparameters and, secondly, a smart interface with the load, witch allows the system to manage a possibly variableload and to adapt to different situations (e.g. insufficient generated power level, load too large, etc.). The study isvalidated by behavioral VHDL-AMS/ELDO modeling.

International audience; In this work, we have successfully implemented an electrostatic transducer in a charge-pump circuit for harvesting the energy from the mechanical vibrations. The transducer is an improved and mechanically reliable version of the resonant capacitive bulk-Si vibration energy harvester that we previously presented in [1]. Despite the low transducer volume of 27 mm3, the targeted external vibration is a harmonic acceleration at 250 Hz of 0.25 g. We demonstrate a harvested power of 103 nW converted from the mechanical to the electrical domain. We have compared the measurements with an accurate mixed VHDL-AMS/Eldo model of the system. The modeling predicts currents and voltages evolution with an inaccuracy of less than 3%.

International audience; This study presents a systematic approach for power-aware design of an optimized capacitive vibration energy scavenger. The proposed method is based on the mechanical domain impedance analysis. First we investigated the mechanical properties (impedance) of the capacitive transducer/conditioning circuit block. We found that this impedance depends strongly on the energy state of the conditioning circuit. From this conclusion we derived a method allowing to find the conditioning circuit operating mode (voltages on the capacitors) maximizing the power yield for a given resonant MEMS transducer block, a given conditioning circuit and given external vibration parameters. This method was successfully applied on the system composed from a charge pump and an inductive flyback circuit. The study was validated by behavioral modeling in VHDL-AMS language environment.

International audience; This paper presents the results of modeling of a mixed non-linear, strongly coupled and multidomain electromechanical system designed to scavenge the energy of ambient vibrations and to generate an electrical supply for an embedded microsystem. The system is operating in three domains: purely mechanical (the resonator), coupled electromechanical (electrostatic transducer associated with the moving mass) and electrical circuit, including switches, diodes and linear electrical components. Although only linear networks can be properly modeled in SystemC-AMS, we propose a technique allowing modeling of electrical networks including non-linear components (diodes) as well as time-varying capacitors. The whole system was modeled using two solvers of SystemC-AMS simultaneously: the one allowing TDF (timed data flow) modeling and the one allowing LIN ELEC (linear electrical) circuit analysis. The modeling results are compared with VHDL-AMS and Matlab Simulink models.

International audience; This paper reports on a comparative study of the modeling techniques for a capacitive resonant vibration energy harvester composed of a resonator, a capacitive transducer and a conditioning circuit. Three accurate models were implemented in three different environments: VHDL-AMS language, SystemC-AMS plate-form and Simulink (Matlab). However, to reduce the modeling time, we also created a simplified Scicos model in which the mechanical part is modeled using SDF blocs such as integrators and adders, and the conditioning circuit was modeled as a Matlab-like script. This simplified model was the most efficient regarding the simulation time, while keeping very good accuracy of the results.

International audience; This paper presents optimization, design and modeling of a conditionning circuit of a vibrational energy harvester with capacitive electromechanical transducer. The conditionning circuit is inspired from the Buck DC-DC converter architecture, and composed from a charge pump and a flyback circuit. We found that the switching should be ordered by the internal state of the circuit, an not by some fixed timing scenario. The paper presents how to find the optimal operation mode of the harvester. To validate the study, the system was modeled using a mixed VHDL-AMS - ELDO model.