Review on Electrodynamic Energy Harvesters—A Classification Approach

Abstract

Beginning with a short historical sketch, electrodynamic energy harvesters with focus on vibration generators and volumes below 1 dm 3 are reviewed. The current challenges to generate up to several milliwatts of power from practically relevant flows and vibrations are addressed, and the variety of available solutions is sketched. Sixty-seven different harvester concepts from more than 130 publications are classified with respect to excitation, additional boundary conditions, design and fabrication. A chronological list of the harvester concepts with corresponding references provides an impression about the developments. Besides resonant harvester concepts, the review includes broadband approaches and mechanisms to harvest from flow. Finally, a short overview of harvesters in applications and first market ready concepts is given.

Approaches for a Fair Comparison and Benchmarking of Electromagnetic Vibration Energy Harvesters

“…If benchmarking results, however, are carefully interpreted, BP (c) and (d) can serve as an appropriate basis for the comparison of resonant electrodynamic harvesters. Figure 3 contains the BPs (a)-(c) applied to the reviewed electrodynamic harvesters in [1]. As several prototypes feature a similar design but different performance, volume, etc., the harvesters are referenced by two numbers: "(?)"…”

“…Key parameters of selected harvesters in SI units estimated/simulated/ cited/computed* from published values. The column "Reference" denotes the particular publication, column "#" was introduced to refer to the corresponding benchmarking value in Figure 3 and the column "Design" refers to our review paper [1] to provide the design principle of the harvester. Note: the key parameters are according to measurement data that provide maximum performance according to BP (c) in Section 3.…”

“…As several prototypes feature a similar design but different performance, volume, etc., the harvesters are referenced by two numbers: "(?)" denotes the design number introduced in our review paper [1] and a single number "?" the benchmark value in the benchmark plots.…”

“…In our very recently published review paper [1] we provided an overview on electrodynamic vibration harvesters that have been published in the past 15 years. We discussed the different designs with different shapes and dimensions and pointed out the huge range of output powers across six orders of magnitude from nW to mW.…”

“…Second, we introduce two novel parameters derived from the linear resonant harvester model. Third, based on the different BPs, the harvesters from our review paper [1] are benchmarked. The results allow to identify high performing harvester designs and design elements and to finally point out beneficial design rules.…”