Kévin Feltrin

Kévin Feltrin

Data Science & AI @ ESIEE Paris | Physics @ Sorbonne | Co-founder of Reaply

CNRS / ESYCOM — Energy harvesting with TENG

Four-week research internship at the CNRS / ESYCOM Laboratory (UMR CNRS 9007).
Goal: simulate and validate a conditioning circuit for a Triboelectric Nanogenerator (TENG) that harvests mechanical energy (vehicle pass) and powers a Bluetooth transmission to a smartphone.

Reference: Nature Communications — “Employing a MEMS plasma switch for conditioning high-voltage kinetic energy harvesters”.

Nature article Report (PDF, in french) Slides (PPTX)

Context & Objective

TENG devices deliver high-voltage, low-current, pulsed outputs—not directly usable by electronics. The project adapts the two-stage chain from the paper—Bennet doubler → hysteresis switch → step-down DC-DC → regulator—to store energy and supply ~3.3–3.6 V for a Bluetooth node.
My task was to compare circuit options, model them in LTSpice, and verify behaviors on a bench prototype and on-site tests.

Approach

  1. Modeling. Full path in LTSpice with parametric sweeps of:
    • Bennet doubler capacitors/diodes (charging efficiency)
    • Hysteresis thresholds (switching stability & charge bursts)
    • Storage & DC-DC (ripple vs. time-to-start)
  2. Measurement. Prototype assembled; node voltages (M, N, P, Q) captured on scope.
  3. Field test. Validation with a vehicle pass over the ramp; alignment/friction tuned for repeatability.

Selected results

  • Node N shows the expected sawtooth charge then burst discharge when the hysteresis triggers.
  • Output Q reaches a stable ~3.3 V, enough to boot a Bluetooth node; storage sizing trades start-up time vs stability.
  • Practical note: mechanical coupling dominates variance; small changes in ramp pressure/position noticeably affect available energy.

What I did

  • LTSpice modeling & sweeps (Bennet, thresholds, storage).
  • Bench measurements and consolidation into operating windows hitting the 3.3 V target.
  • Recommendations: improved mechanical fixture, lower-drop diodes, and soft-start on the DC-DC stage.
Conditioning chain: Bennet doubler → hysteresis switch → step-down DC-DC → regulator → load
Figure 1. High-level conditioning chain from TENG to regulated output with probe nodes (M, N, P, Q).
Energy-harvesting ramp used for vehicle pass tests
Figure 2. Energy-harvesting ramp used for vehicle pass tests to feed the TENG module.
LTSpice – voltage at node N
Figure 3. LTSpice — Node N: cumulative charge with sawtooth growth prior to switching.
LTSpice – regulated output Q ≈ 3.3 V
Figure 4. LTSpice — regulated output Q ≈ 3.3 V for the Bluetooth node.
Bench prototype of the conditioning circuit
Figure 5. Bench prototype and oscilloscope captures.
Triboelectric Nanogenerator (TENG) element
Figure 6. Triboelectric Nanogenerator (TENG) element.