IEEE Circuits and Systems Magazine - Q3 2018 - 40

detection module to determine the maximum or minimum
peak voltage generated by the piezoelectric element. This
approach has one main drawback; namely, it is usually unstable because it is generally very sensitive to noise.
The second technique, Fig. 20(b), consists of the use
of the differentiation operator. Applying a delay to the
input voltage source and then correlating the piezoelectric voltage and the relative deferred version, it is possible to detect when the output voltage on the piezoelectric element is at its maximum or at its minimum.
Another approach can be found in [72], in which a
Velocity control Synchronized Switching Harvesting on
Inductor (V-SSHI) interface was implemented with a velocity control block used to autonomously control the
switch. The control scheme is implemented with a current detector followed by a low-pass filter. A comparator
is then used to detect the zero-voltage crossing of the
output voltage of the filter.

Bridge rectifiers combined with MPPT algorithms
are the most common solution adopted to maximize
power transfer.
Full-bridge (FB) and half-bridge rectifiers or Voltage
Doublers (VD) are commonly used to convert the input
AC voltage into DC voltage. If we neglect the diode voltage drop Vd, both half- and full-bridge rectifiers have the
same maximum power expression Pmax:
Pmax = C p (VOC) 2 ~

where C p is the parasitic capacitance of the piezoelectric material, ~ the vibration frequency and VOC the
open circuit voltage produced by the piezoelectric element. Instead, when we consider the diode voltage drop
Vd, the power that can be theoretically achieved using a
FB and VD rectifier is given by Eq. (14) [86], [87], where
VRect is the output rectified voltage:
PVD = C p Vrect (2VOC - Vrect - 2Vd) ~
PFB = 4C p Vrect (VOC - Vrect - 2Vd) ~

IV. MPPT-Based PEH Rectifiers
Another popular approach, widely employed to harvest energy from piezoelectric transducers, is based on
MPPT algorithms used to monitor and regulate the resistance seen by the piezoelectric element, as shown in Fig. 21.

Piezoelectric Voltage

(13)

(14)

Considering the two expressions Eq. (14), the maximum power that can be theoretically extracted using a
VD rectifier and a FB rectifier can be derived as in Eq. (15).

∂ /∂ t
"0"

Comparator

Switch Driver

Comparator

Switch Driver

(a)
Piezoelectric Voltage

Delay + Storage
Element

(b)
Figure 20. self-powered autonomous switching control schemes used in resonant rectifiers: (a) applying the derivative operator,
and (b) applying the differentiation operator.

PEH

ac-dc
Converter

dc-dc
Converter

Cs

dc-dc
Converter

MPPT
Figure 21. conventional mPPT interface employing two Dc-Dc converters.
40

Ieee cIRcuITs anD sysTems magazIne

THIRD quaRTeR 2018



Table of Contents for the Digital Edition of IEEE Circuits and Systems Magazine - Q3 2018

Contents
IEEE Circuits and Systems Magazine - Q3 2018 - Cover1
IEEE Circuits and Systems Magazine - Q3 2018 - Cover2
IEEE Circuits and Systems Magazine - Q3 2018 - Contents
IEEE Circuits and Systems Magazine - Q3 2018 - 2
IEEE Circuits and Systems Magazine - Q3 2018 - 3
IEEE Circuits and Systems Magazine - Q3 2018 - 4
IEEE Circuits and Systems Magazine - Q3 2018 - 5
IEEE Circuits and Systems Magazine - Q3 2018 - 6
IEEE Circuits and Systems Magazine - Q3 2018 - 7
IEEE Circuits and Systems Magazine - Q3 2018 - 8
IEEE Circuits and Systems Magazine - Q3 2018 - 9
IEEE Circuits and Systems Magazine - Q3 2018 - 10
IEEE Circuits and Systems Magazine - Q3 2018 - 11
IEEE Circuits and Systems Magazine - Q3 2018 - 12
IEEE Circuits and Systems Magazine - Q3 2018 - 13
IEEE Circuits and Systems Magazine - Q3 2018 - 14
IEEE Circuits and Systems Magazine - Q3 2018 - 15
IEEE Circuits and Systems Magazine - Q3 2018 - 16
IEEE Circuits and Systems Magazine - Q3 2018 - 17
IEEE Circuits and Systems Magazine - Q3 2018 - 18
IEEE Circuits and Systems Magazine - Q3 2018 - 19
IEEE Circuits and Systems Magazine - Q3 2018 - 20
IEEE Circuits and Systems Magazine - Q3 2018 - 21
IEEE Circuits and Systems Magazine - Q3 2018 - 22
IEEE Circuits and Systems Magazine - Q3 2018 - 23
IEEE Circuits and Systems Magazine - Q3 2018 - 24
IEEE Circuits and Systems Magazine - Q3 2018 - 25
IEEE Circuits and Systems Magazine - Q3 2018 - 26
IEEE Circuits and Systems Magazine - Q3 2018 - 27
IEEE Circuits and Systems Magazine - Q3 2018 - 28
IEEE Circuits and Systems Magazine - Q3 2018 - 29
IEEE Circuits and Systems Magazine - Q3 2018 - 30
IEEE Circuits and Systems Magazine - Q3 2018 - 31
IEEE Circuits and Systems Magazine - Q3 2018 - 32
IEEE Circuits and Systems Magazine - Q3 2018 - 33
IEEE Circuits and Systems Magazine - Q3 2018 - 34
IEEE Circuits and Systems Magazine - Q3 2018 - 35
IEEE Circuits and Systems Magazine - Q3 2018 - 36
IEEE Circuits and Systems Magazine - Q3 2018 - 37
IEEE Circuits and Systems Magazine - Q3 2018 - 38
IEEE Circuits and Systems Magazine - Q3 2018 - 39
IEEE Circuits and Systems Magazine - Q3 2018 - 40
IEEE Circuits and Systems Magazine - Q3 2018 - 41
IEEE Circuits and Systems Magazine - Q3 2018 - 42
IEEE Circuits and Systems Magazine - Q3 2018 - 43
IEEE Circuits and Systems Magazine - Q3 2018 - 44
IEEE Circuits and Systems Magazine - Q3 2018 - 45
IEEE Circuits and Systems Magazine - Q3 2018 - 46
IEEE Circuits and Systems Magazine - Q3 2018 - 47
IEEE Circuits and Systems Magazine - Q3 2018 - 48
IEEE Circuits and Systems Magazine - Q3 2018 - Cover3
IEEE Circuits and Systems Magazine - Q3 2018 - Cover4
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2023Q3
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2023Q2
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2023Q1
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2022Q4
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2022Q3
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2022Q2
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2022Q1
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2021Q4
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2021q3
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2021q2
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2021q1
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2020q4
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2020q3
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2020q2
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2020q1
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2019q4
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2019q3
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2019q2
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2019q1
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2018q4
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2018q3
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2018q2
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2018q1
https://www.nxtbookmedia.com