=Paper=
{{Paper
|id=Vol-3206/paper12
|storemode=property
|title=Research on Vibration Energy Acquisition Method of Piezoelectric Generator
|pdfUrl=https://ceur-ws.org/Vol-3206/paper12.pdf
|volume=Vol-3206
|authors=Yi Cao,Shuangjie Liu,Yongping Hao,Kai Ma
|dblpUrl=https://dblp.org/rec/conf/iscipt/CaoLHM22
}}
==Research on Vibration Energy Acquisition Method of Piezoelectric Generator==
https://ceur-ws.org/Vol-3206/paper12.pdf
Research on Vibration Energy Acquisition Method of
Piezoelectric Generator
Yi Cao 1, Shuangjie Liu1, Yongping Hao1, Kai Ma1
1
School of Equipment Engineering, Shenyang Ligong University, Shenyang, Liaoning, China
Abstract
With the modern weapon system to fuze reliability, security, versatility and storage life and
other technical requirements are becoming higher and higher, the traditional chemical battery
power supply mode can not meet the requirements of modern weapon fuze power supply. In
order to meet the power supply needs of modern fuze, based on the analysis of the electrical
characteristics of piezoelectric materials, the vibration energy acquisition method of the fuze
piezoelectric generator is studied, and the energy acquisition method of the fuze piezoelectric
generator is optimized, so as to achieve the purpose of efficiently collecting the output energy
of the piezoelectric generator. The research method in this paper provides a theoretical
reference for the research of vibration and piezoelectric energy acquisition technology of
piezoelectric generator, and provides a reference for the further research and design of vibration
energy acquisition technology.
Keywords1
Piezoelectric vibration energy, Energy collection, Power management
1. Introduction
Vibration energy is a common energy of natural environment, which is widely used in military
facilities, industrial equipment, human movement and biological activities. Piezoelectric vibration
power generation devices are widely used in vibration energy capture because of their advantages such
as simple structure, flexible shape, high energy density and easy miniaturization [1-2].Because of its
advantages of simple structure, flexible shape, high energy density and easy to realize miniaturization,
piezoelectric vibration generator is widely used in vibration energy capture. However, due to the high
capacitive impedance of piezoelectric materials, the output power of the generator has the
characteristics of low current and high voltage, and its output power is related to the load. At the same
time, because of the characteristics of vibration energy, the output of the piezoelectric generator is AC
electric energy, and can not directly charge the battery or power the fuze load equipment. Therefore, a
power collecting circuit must be added between the piezoelectric generator and the fuze load equipment,
whose function is to realize AC - DC conversion and improve the output power of the piezoelectric
generator[3].
2. DC - AC rectifier circuit
Due to the characteristics of vibration energy, the output is AC electric energy, which can not directly
charge the battery or power the load. Therefore, AC/DC rectifier circuit should be added between
piezoelectric material and load to collect electric energy.
ISCIPT2022@7th International Conference on Computer and Information Processing Technology, August 5-7, 2022, Shenyang, China
EMAIL: 243641220@qq.com (Yi Cao); Corresponding author: shuangjieliu@126.com (Shuangjie Liu); yphsit@126.com (Yongping Hao);
982750993@qq.com (Kai Ma)
Β©οΈ 2022 Copyright for this paper by its authors.
Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
CEUR Workshop Proceedings (CEUR-WS.org)
79
2.1. Standard energy harvesting circuit
Figure 1 shows the traditional standard energy collection circuit, which is the simplest and most
classical full-bridge rectifier circuit. The entire circuit consists of four diodes, with R0 representing the
load.
Figure 1: Standard energy harvesting circuit
It is assumed that the electric energy excitation generated by the vibration F of the piezoelectric
material is the standard sinusoidal oscillation excitation, defined as
π(π‘) = π0 sinβ‘(ππ‘) (1)
In EquationοΌ1οΌοΌV0 is voltage amplitude and Ο is vibration frequency. According to Kirchhoff's
law and the piezoelectric equation, the voltage on the load resistance R0 can be obtained as follows:
πΌππ(π
0 + 2π
π· ) (2)
ππ
= π
(π
0 + 2π
π· )πΆπ π + 2
In Equation οΌ 2 οΌ οΌ Ξ± is electromechanical coupling factor, U is vibration displacement of
piezoelectric material, R0 is load resistance, RD is rectifier diode loss resistance, CP is internal static
capacitance of piezoelectric material. Then, the average power on the load resistor is:
ππ
2 π
0 (π
0 + 2π
π· )πΌ 2 π2 π2 π
0 (3)
Μ
Μ
Μ
ππ
= =
π
0 + 2π
π· π 2
[(π
0 + 2π
π· )πΆπ π + 2 ]
Because of the simple structure of standard energy collection circuit, its application field is very
wide, but the circuit has the problems of low collection efficiency and high energy loss, and there are
many places to be improved.
2.2. MOSFET energy collection circuit
In order to eliminate the problem of high starting voltage and high power consumption caused by a
large diode voltage drop, the power MOSFET is used to replace the rectifier and form an active rectifier
circuit. The voltage drop of MOSFET is close to zero, and it has approximately the circuit characteristics
of ideal diode. Therefore, the power loss and starting voltage of the rectifier circuit can be reduced, and
the energy collection efficiency can be improved.
[4]
As shown in Figure 2, the voltage comparator is used to cross-couple NMOS and PMOS , so that
the MOSFET can work in the amplification area, so that it can be completely closed, and improve the
energy collection efficiency. The principle is that when the output voltage of piezoelectric material is
in a positive half period, becauseβ‘πππ’π‘ β π1 > |πππ»π1 |, At this point, MP1 and MN2 are on, and MP2 and
MN1 are off. At the end of CP discharge, when V1=V2, all MOSFET cut off. Similarly, when the output
voltage of piezoelectric material is in negative half period, due to πππ’π‘ β π2 > |πππ»π2 |, At this point,
MN1 and MP2 are on, and MN2 and MP1 are off.
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Figure 2: MOSFET energy collection circuit
According to Kirchhoff's law and the piezoelectric equation, the voltage on the load resistance R 0
can be obtained as follows:
πΌπππ
0 (4)
ππ
= π
π
0 πΆπ π + 2
The average power on the load resistor is:
ππ
2 π
0 πΌ 2 π2 π 2 (5)
Μ
Μ
Μ
ππ
= =
π
0 (π
0 πΆπ π + )2 π
2
According to the Equation (5), under the condition of constant vibration displacement U of
piezoelectric material, there exists an optimal load resistance and maximum output power:
π (6)
π
πππ =
2πΆπ π
ππΌ 2 π 2 (7)
πππ΄π =
2ππΆπ
3. Passive power factor correction circuit
After the electric energy output by piezoelectric material passes the rectifier circuit, its voltage
waveform is close to the DC circuit, and the current produces distortion and distortion because the
conduction time of the rectifier tube is too short, which becomes a spike pulse and reduces the power
factor. The passive power factor correction method is to make the input current of the circuit close to
sine wave by adding passive components such as capacitance and inductance into the circuit, that is, to
improve the power factor through reactive power compensation, so as to achieve the purpose of
[5]
increasing active power . Compared with other circuits, grain filling circuit needs fewer components
and has better performance. The grain filling circuit is shown in Figure 3.
Figure 3: Passive power factor correction circuit
Its working principle: when the capacitor in the filling circuit is charged, the capacitor in the circuit
in series to reduce the capacitance value, to achieve the purpose of fast charging; When discharging,
the capacitor is in parallel, and the voltage at both ends of the capacitor is 1β n of the peak total voltage
(n is the order of the capacitor), which reduces the circuit's recharging inch charging voltage threshold.
When the circuit is charging, D1 in the filling circuit is on, D2 and D3 are off, and the two filter
capacitors are connected in series. The series of capacitors reduces the total capacitance value and
therefore the time constant. When the circuit discharges, D1 in the filling circuit shuts off, D2 and D3
are on, and the two filter capacitors are connected in parallel. The voltage at both ends of each capacitor
is 1β2 peak voltage, which reduces the charging threshold when the circuit is recharged.
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Output power of grain filling circuit is:
ππ
2 4π02 πΆπ2 π2 π
(8)
π= =
π
(2πΆπ π
π + π)2
With ππ/ππ
= 0, it can be known that the maximum output power and optimal load resistance of
piezoelectric material are:
π02 πΆπ π (9)
πππ΄π =
2π
π (10)
π
πππ =
2ππΆπ
Valley filling circuit can greatly increase the conduction Angle of rectifier tube, by filling the valley
point, the input current from the peak pulse to the waveform close to the sine wave, reduce harmonic
content, improve the power factor, significantly reduce waveform distortion.
4. BUCK - BOOST circuit
The waveform of the circuit corrected by the filling circuit is similar to that of the DC power supply.
At this time, the output voltage can be adjusted by the buck-Boost circuit to make the output voltage
meet the requirements of the load. The circuit is shown in Figure 4.
Figure 4: BUCK - BOOST circuit
Its working principle: when the switch S is closed, the inductor L1 is directly connected to both ends
of the power supply, and the inductance current gradually rises. The ππ/β‘ππ‘ is very large in the transient
state, so the input capacitor C1 is the main power supply during this process. At the output end, C2
provides energy for R0 by its own discharge. When switch S is off, power supply V charges the input
capacitor. Since the current of the inductor cannot be mutated, the inductor L1 supplies power to the
output capacitor C2 and the load R0 through the continuation tube D1. After stable operation, the
inductance is conserved in volts second. When the switch S is on, the inductance voltage is equal to the
input power voltage VIN; When switch S is off, the inductance voltage is equal to the output voltage
VOUT. Let T be the cycle, TON be the on-time, TOFF be the off time, D be the duty cycle.
π· (11)
ππππ = π
1 β π· πΌπ
When duty cycle is less than 0.5, output step-down; When duty cycle is greater than 0.5, output
boost.
5. Simulation
The circuit is shown in Figure 5, figure 6 is the simulation of traditional energy collection circuit,
and Figure 7 is the simulation of induced piezoelectric energy collection circuit.
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Figure 5: Lead the piezoelectric energy collection circuit
Figure 6: The simulation of traditional energy collection circuit
Figure 7: The simulation of lead the piezoelectric energy collection circuit
It is assumed that the voltage amplitude of the input AC voltage source is 5V, and the peak voltage
of the traditional energy collection circuit is 2.102V and the valley is 1.331V. After using the new
energy collection circuit, the peak voltage is 3.577V and the valley is 2.034V.
6. Conclusion
Comparing the output voltage of the traditional energy collection circuit with that of the induced
piezoelectric energy collection circuit, the peak voltage is increased by 1.455 V, the valley value is
83
increased by 0.703 V, the average output voltage is increased by 29.4%, and the energy collection
efficiency is improved to a certain extent.
In this paper, a piezoelectric energy collection circuit with low power consumption and high
acquisition efficiency is designed, which uses active diode instead of traditional diode to reduce the
voltage loss and improve the power conversion efficiency.
7. References
[1] Cao Dongxing, Ma Hongbo, Zhang Wei. Analysis on energy capture characteristics of
piezoelectric cantilever beam induced by flow. Chinese journal of theoretical and applied
mechanics. 2019,51(4):1148-1155.
[2] Richelli A,Colalongo L,Kovacs-Vajna Z. A review of dc/dc converters for ultra low voltage
energy harvesting.Journal of Low Power Electronics, 2016, 12(2): 138-149
[3] Chen Nan, Liu Jingrui, Wei Tingcun. Review of Power management Circuits for Piezoelectric
vibration energy capture. Chinese journal of theoretical and applied mechanics.
https://kns.cnki.net/kcms/detail/11.2062.O3.20210930.1802.002.html
[4] Sun Y, Hieu N H, Jeong C, et al. An integrated high-performance active rectifier for
piezoelectric vibration energy harvesting systems. IEEE Transactions on Power Electronics, 2012,
27(2): 623-627
[5] Ben Hongqi, Zhang Jihong, Liu Guihua et al. Active Power factor Correction technology in
switching power supply first edition Beijing: China Machine Press,2010
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