Electrostatic Conversion for Vibration Energy Harvesting

Abstract

This chapter focuses on vibration energy harvesting using electrostatic converters. It synthesizes the various works carried out on electrostatic devices, from concepts, models and up to prototypes, and covers both standard (electret-free) and electret-based electrostatic vibration energy harvesters (VEH).After introducing the general concept of Vibration Energy Harvesting and the global advantages and drawbacks of electrostatic devices to convert mechanical power into electricity ( §1), we present in details the conversion principles of electret-free and electret-based electrostatic converters and equations that rule them in §2. An overview of electrostatic VEH, comparing the results from several laboratories (powers, sizes, concepts…) is provided in §3. In §4, we introduce several power management circuits dedicated to electrostatic VEH. These circuits are extremely important as they are the only way to turn VEH output powers into viable supply sources for electronic devices (sensors, microcontrollers, RF chips…). Assessments, limits and perspectives of electrostatic VEH are then presented in §5.

Electrostatic Energy Harvesting Systems: A Better Understanding of Their SustainabilityElectrostatic Energy Harvesting Systems: A Better Understanding of Their Sustainability

“…The layer is then left to cool down to maintain an electric field. This allows the dipoles of the dielectric layer to be oriented in the same direction as the electric field [1], as shown in Fig. 3.…”

“…Therefore, the authors suggested that the air gap must be controlled precisely and minimized to achieve high capacitances. Moreover, it is also important to prevent from electrical breakdown problems [1].…”

“…INTRODUCTION Electrostatic converters are capacitive devices in which energy conversion takes place as the plates of a variable capacitor separate or the area of the plates is modified in response to externally applied mechanical energy [1]. The main unit of an electrostatic energy harvester is its variable capacitor, which makes use of a change in capacitance to either cause a voltage increase or a charge increase in the harvesting system.…”

Survey of Energy Harvesting Systems for Wireless Sensor Networks in Environmental Monitoring

“…In the standby mode a typical energy demand is estimated to be up to a dozen μW, whereas in the measurement mode the demand can be either small or very large -from 0.1 μW to 100 mW during communication. These values of energy can be supplied by an efficient power supply in a sensor node based only on EH [16]. The rectifier, buffer, and stabilizer systems must have a high energy efficiency.…”

Mechanical Behavior of A MEMS Based Capacitive Energy Harvester

“…They both start when the converter's capacitance is maximal. At this point, a charge is injected into the capacitor thanks to an external source, to polarize it [3].…”