electronic electrostatic machines
By 2015, I started some experiments with
electrostatic generators made with 3D-printing techniques, with the
objective of developing generators that could be used for energy
harvesting applications. The generators were based on variable capacitors,
with their structures printed with conductive ABS filament. These
generators operate at very high impedance level, and so are insensitive to
the resistivity of the material.
The first experiment was with a device comprising two pairs of
complementary variable capacitors, that could be interconnected in several
ways along with four high-voltage diodes and extra capacitors to create
different generators , . It was moved by a small motor in a
back-and-forth movement. It worked very well, but with a low maximum
speed, of about 10 Hz.
complementary variable capacitors with back-and-forth movement.
The second experimental device used a
pair of multiple comb capacitors, with a movable part suspended from
springs and driven at the mechanical resonance, 18 Hz, by a solenoid
acting on a magnet. The structure was designed to be compatible with
construction as microelectromechanical systems (MEMS). A complex
demonstration system was built around the device, extracting energy
using a low-power DC/DC converter and using the energy to power a
digital wireless link, exchanging data with a remote transceiver ,
. The system also worked well, and could generate enough energy for
multiple comb machine with resonant movement, DC/DC converter and load
In the experiments related in the references, the devices were limited to
operate at 300 V at the input of the DC/DC converter, when it was used.
The small distances between the capacitor plates (~1 mm) limited the
maximum voltage over the variable capacitors to about 1 kV.
of the resonant generators. Demonstration
at the ISCAS 2017.
 A. C. M. de Queiroz and L. C. M. de Oliveira Filho, Energy
harvesting with 3D-printed electrostatic generators
, LASCAS 2016,
Florianópolis, Brazil, pp. 127-130, February 2016.
 A. C. M. de Queiroz and N. Telles de Menezes, Energy
harvesting with pairs of variable capacitors without control systems
Analog Integrated Circuits and Signal Processing, June 2018. Direct link
 A. C. M. de Queiroz and L. C. M. de Oliveira Filho, Live
demonstration: Unipolar symmetrical variable-capacitance generators
for energy harvesting
, ISCAS 2017, Baltimore, USA, p. 1739, May
 A. C. M. de Queiroz and L. C. M. de Oliveira Filho, Unipolar
symmetrical variable-capacitance generators for energy harvesting
60th MWSCAS, Boston, USA, August 2017.
By Antonio Carlos M. de Queiroz
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