Series-Parallel Charge Pump Conditioning Circuits for Electrostatic Kinetic Energy Harvesting

Abstract

International audienceThis paper presents a new family of conditioning circuits used in electrostatic kinetic energy harvesters (e-KEHs), generalizing a previously reported conditioning circuit known as the Bennet's doubler. The proposed topology implements a conditioning scheme described by a rectangular charge-voltage cycle (QV-cycle) of tunable aspect ratio. These circuits show an exponential increase of the converted energy over operation time if studied in the sole electrical domain. The QV-cycle's aspect ratio can be set to values that were previously inaccessible with other exponential conditioning circuits. After a brief intuitive presentation of the new topology, its operation is rigorously analyzed and its dynamics are quantitatively derived in the electrical domain. In particular, the aspect ratio of the rectangular QV-cycle describing the biasing scheme of the transducer is expressed as a function of the circuit's parameters. Practical considerations about the use of the reported conditioning circuits in actual e-KEHs are also presented. These include a discussion on the applications of the proposed conditioning, a description of the effects of electrical nonidealities, and a proposition of an energy extracting interface

Analysis and comparison of charge-pump conditioning circuits for capacitive electromechanical energy conversion

“…Our analysis, fully-reported in [6], shows that these circuits implement the generic CPCC QV diagram depicted in Fig. 1b, with a constant ratio pV R {V L q CW throughout the circuit's operation.…”

A Novel Characterization Method for Accurate Lumped Parameter Modeling of Electret Electrostatic Vibration Energy Harvesters

“…To estimate the influence of random error sources on the measurement using (5)(6), E is first estimated at 20V, by a surface potential measurement done 1mm on top of the device using a contact-less electrostatic voltmeter. The four values of η are measured by synchronous detection, and δ V is measured as 25mV.…”

“…where ξ :" C S {C min and η :" C max {C min . From (5)(6), it comes that the measurement uncertainty due to random error sources decreases by decreasing C S . However, decreasing C S increases the electromechanical coupling effect on the e-VEH's dynamics, thereby inducing a systematic measurement error on C max and E. This is because equations (3-4) are derived from (1-2) assuming that pC max , C min q with circuit HW1 (in (1)) are equal to pC max , C min q with circuit HW2 (in (2)).…”

“…In the recent years, the complexity of the available conditioning circuits has increased to optimize the harvesters performances [3]- [6]. As a result, the use of lumped parameter models of e-VEHs is becoming the sole convenient way to predict their dynamics under variable input conditions.…”

Employing a MEMS plasma switch for conditioning high-voltage kinetic energy harvesters

“…In this paper, we report a self-sustained conditioning system that allows the TENG to work at high-voltages for high-energy conversion without power-consuming electronics, using an unstable charge pump (Bennet doubler) combined with a highvoltage microelectromechanical system (MEMS) plasma switch in a 2-stage circuit. The Bennet doubler solves the V TE voltage limitation issue by generating an exponential transient charging process with positive base of exponentiation 32,44,45 . Such a transient process has no saturation limit, except those imposed by the breakdown voltage of the device insulators 46 , the possible spring-softening phenomena occurring in resonating devices 32 or limitations from electrical components.…”