OPEN ACCESS Asian Journal of Scientific Research

ISSN 1992-1454DOI: 10.3923/ajsr.2016.176.187

Research ArticleSimulation of 416 kHz Piezoelectric Transducer Excitation usingClass E ZVS Inverter1H. Husin, 1S. Saat, 1Y. Yusmarnita, 1Z. Ghani, 1I. Hindustan and 2S.K. Nguang

1Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia2University of Auckland, Victoria Street West, Auckland 1142, New Zealand

AbstractIn Acoustic Energy Transfer (AET) system, piezoelectric transducers played a role in converting the electrical energy to mechanical stressor vice versa. It is required to drive the piezoelectric transducer in the transmitter unit at the exact operating frequency, so that the highefficiency of power conversion can be achieved. This study presents the simulation model of the excitation circuit to drive the piezoelectrictransducer using class E ZVS as DC-AC inverter in the transmitter unit of AET system. As design specifications with the PZT transduceroperating frequency of 416 kHz, 80 mW power output is aimed from the inverter circuit. Proteus software used as simulation platformwith peripheral interface controller (PIC16F877A) as Pulse Width Modulation (PWM) signal generator for MOSFET IRF5852TR. Thetransmitter unit is modeled in stages started with optimum operation of class E ZVS, followed by the insertion of piezoelectric transducerequivalent circuit and end up with the matching impedance circuit in order to achieve maximum power conversion as the main concernsof this study. The simulation result from the proposed design generates a 72.22 mW with 90.3% efficiency. This signifies that simulationresults agree upon the theoretical calculation.

Key words: Acoustic energy transfer, DC-AC transmitter, PWM, piezoelectric transducer, class E ZVS

Received: May 10, 2016 Accepted: August 06, 2016 Published: September 15, 2016

Citation: H. Husin, S. Saat, Y. Yusmarnita, Z. Ghani, I. Hindustan and S.K. Nguang, 2016. Simulation of 416 kHz piezoelectric transducer excitation usingclass E ZVS inverter. Asian J. Sci. Res., 9: 176-187.

Corresponding Author: H. Husin, University Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia

Copyright: © 2016 H. Husin et al. This is an open access article distributed under the terms of the creative commons attribution License, which permitsunrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.

Competing Interest: The authors have declared that no competing interest exists.

Data Availability: All relevant data are within the paper and its supporting information files.

Asian J. Sci. Res., 9 (4): 176-187, 2016

INTRODUCTION

Numerous established of Wireless Power Transfer (WPT)technologies gained attracting attention from the researchercurrently. Not only due to their capabilities to chargeconsumer home appliances, but also contributes to othertechnical aspects such as, supplying the power tosensors/transducers embedded in a human body or charginga moving vehicle on the road. The WPT is also implemented in the industries which required the wear ofcable slabs to be minimized as reported in Hu et al.1. Arelatively new alternative method is an Acoustic EnergyTransfer (AET), which utilizes sound waves or vibration topropagate energy without depending on the electricalconnection between the transmitter and receiver unit. TheAET comes into the picture of energy transferring technologydue to the urgent requirement of alternative methods ofpowering low power consumption as proposed by Roes et al.2,Sanni and Vilches3, Ozeri and Shmilovitz4 and Denisov andYeatman5 such as for Implantable Biomedical Devices (IMDs).Zaid et al.6 claimed that other practical alternatives in thesame category of AET for powering those devices include: (i)Inductive Energy Transfer (IET), (ii) Capacitive energy transfer(CPT), (iii) Far-field electromagnetic coupling (EM) and (iv)Optical coupling techniques. The IET has gained a hugeattention since the systems managed to deliver energy up to2 m with high efficiency as reported by Karalis et al.7 andKurs et al.8, but due to magnetic coupling issue, it is notsuitable for metal surrounding environment and cause oflarge eddy current losses as claimed by Roes et al.2,Theodoridis9 and Liu et al.10. The CET takes advantages ofthese limitations due to its nature that exploits an electric fieldto penetrate through any metal surroundings. The CET hasalso a good anti-interference ability of the magnetic field asstated by Liu et al.10, Kline et al.11 and Chen-Yang et al.12. Theimplementation of CET is limited due to the restriction ofdistance that can be crossed with it and have been usedfor very low power delivery applications proposed by Theodoridis9, Chen-Yang et al.12, Zaid et al.6 and Kline et al.11.Far-field electromagnetic coupling (EM) is seldom used

because of the difficulty in microwaves generation especiallywhen a solid-state RF generator is applied and for IMDsapplications, side effect that harmful to the human body.Optical energy transmission uses same principles as EMand has low efficiency whereby up to 50% energy is lostaccording to Zaid et al.6 and Roes et al.2. The abovementioned characteristics make acoustics a primary candidate for WPT in low power applications (in range of µW to mW) due to its power transfer efficiency, compactness and

electromagnetic immunity as concluded by Jiang et al.13,Miller14 and Semsudin et al.15.In AET systems, the piezoelectric transducer plays a major

role in converting an electrical energy to pressure energy orvice-versa. The transducer electrical impedance will affectnoise performance, driving response, bandwidth andsensitivity as laid by Svilainis and Dumbrava16. Thus, it isrequired to take into consideration the approach to predictthe performance of the piezoelectric transducer as a part ofthe system.This study presents the working principle of class E Zero

Voltage Switching (ZVS) as soft-switching inverter topology inthe transmitter unit of AET system due to its capability toproduce high efficiency inverter performance. The highefficiency inverter performance is required for two reasons:(1) To drive the piezoelectric (PZT) transducer at the exactoperating frequency without introducing harmonic modes sothat maximum DC-AC conversion can be achieved and (2)Prolong the low voltage, low power battery’s service life thatsupplied the transmitter unit. However, this study will dealtonly with the first reason due to simulation ability.This study presents and compares the performance of AET

transmitter unit for three conditions: (1) With the optimumcondition class E ZVS inverter, (2) With the optimum conditionclass E ZVS inverter attached to PZT equivalent electricalcircuit and iii) with the optimum condition class E ZVSattached to PZT equivalent electrical circuit with matchingimpedance.

AET system: The basic structure of AET system is shown inFig. 1 that consists of 2 U, primary/transmitter unit andsecondary/receiver unit that's been separated by any materialthat can propagate sound/pressure waves as a transmissionmedium. In the transmitter unit, the power converter orinverter will converts a dc supply to an ac supply that beinginjected to piezoelectric transducer. The transducer willconverts that energy to pressure wave which is thentransmitted wirelessly. The pressure is collected by anothertransducer at the receiver side that reconverts the energy backinto electrical energy and being amplified based on the loadrequirements. The transmission medium can be ranged forexamples metal, air, human tissue and solid wall as long as itcan allow the penetration of pressure wave. An AET systemcan be applied at the various applications such as ultrasoniccleaning, medical ultrasonography, non-destructive testing,distance measurement (sonar), therapeutic ultrasound andultrasonic welding. Recently, the urgent demand of thealternative recharging method, especially for ImplantableBiomedical Devices (IMDs) shows a trend of applying an AETsystem.

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Lf L

ll iS iC1

+

vS

C1

+ vX

C

OVl Ri vRi

+_

i

__

Fig. 1: Basic AET system by Zaid et al.6

Fig. 2: Class E zero-voltage-switching inverter by Kazimierczukand Dariusz18

Table 1: Load network characteristicsSwitch condition Resonant frequency Loaded quality factor

Turns on 01

1f

(2 LC)

01

L1i

LQ

R

=01 i

1

( CR )

Turns off02

1

1

1f

LCC2

C C

02L2

i

LQ

R

= 02 1

1

1

LCC( C C )

CLASS E ZVS INVERTER WORKING PRINCIPLE

Class E ZVS inverters are the most efficient and excellentsoft switch inverters circuit, which capable in reducing thevoltage stress and switch conduction loss in the resonantcircuit as described by Nayak and Reddy17, Kazimierczuk andDariusz18 and Li and Sue19. Li and Sue19 claimed that class E stillmanageable to operate at the high efficiency even the varyingvalues of resonant components. It can also produce goodperformance and stability by adjusting the duty cycle andoptimizing circuit parameters that supported by Xiaoyuan andZhe20. The current and voltage waveforms of the switch arenot overlap during the switching time intervals thus theswitching losses are virtually zero, yielding high efficiency. The

nature of switching operation that contributing to the highefficiency is controlled by L-C resonant those operate at theinstant of zero voltage crossing condition. The circuit diagramis shown in Fig. 2. It consists of power MOSFET that act as aswitch, a L-C-Ri series resonant circuit, C1 as shunt capacitorand Lf as choke inductor. The switch turns on and off at theoperating frequency f = T/(2π) that determined by a driver.The resistor Ri is an AC load.When the switch is turns on, the resonant circuit

consists of L, C and Ri because the capacitance C1 is shortcircuited by the switch. However, in the off state, the resonantcircuit will consists of C1, L, C and Ri that connected in series. Thus, the load network can be characterized by two resonantfrequencies and two loaded quality factor as tabulated inTable 1.

MATERIALS AND METHODS

The simulations are carried out in three stages:

C Firstly, the transmitter will be equipped with class E ZVSinverter that working at its optimum operation

C Secondly, the first stage is extended with a piezoelectrictransducer equivalent circuit to support system levelanalysis

C Lastly, due to change of AC load value, the matchingimpedance circuit will be presented at this stage wherebythe main objective of the research can be obtained

Stage 1: Optimum operation of class E ZVSTheoretical calculation of class E ZVS components: Inthis study, the optimum operation of class E ZVS inverteris studied and simulated. Figure 3 shows the current andvoltage waveform for optimum operation. In this case,both the switch voltage vs and its derivatives dvs/dt arezero when the switch is turns on. The optimum operation occurred when the maximum drain efficiency is achieved. Due to the derivatives of vs is zero at the time the

178

Transmission medium

Secondary unit Primary unit

Receiving transducer

Transmitting transducer

Power converter

Rectifier Load

Asian J. Sci. Res., 9 (4): 176-187, 2016

wt

wt

wt

wt

wt

wt

wt

vGS

l -i1

vS1

lSM

O

ll

Oi

vGS

S ON S OFF

2 D t2 D t

ll

O

ll-i

O

OiC1

vS

O

O

iS

2

VSM

t

t

O

O

vDS

vGS

vt

Fig. 3: Optimum operation waveforms in class E ZVS inverterin Kazimierczuk and Dariusz18

Fig. 4: Relationship of vGS and vDS waveforms for class E ZVSinverter

switch turns on, the switch current is increased gradually fromzero after the switch is closed. For optimum operation, theswitch voltage and the switch current are at positive level thuseliminating the requirement of additional diode to the switch.The waveforms of gate-to-source voltage vGS and

drain-to-source voltage vDS for operation of ZVS in the class Einverter is depicted in the Fig. 4. The operation must satisfythis condition in order to achieve high efficiency inverter.The equation involved in component’s value in the

optimum operation at duty cycle, D = 0.5 is obtained andaltered from Kazimierczuk and Dariusz18 as below.

The AC load of the inverter can obtained:

(1)

2I

i 2Ri

8VR =

( + 4)P

The value of shunt capacitor:

(2)0

2 21

i

I 1

VR 1

4 2

1C =

The value of series capacitor (from L, C, Ri resonantcircuit):

(3)2

i

1

( 4R Q

16

C =

The value of choke inductor:

(4)2

f

RL 2 1

4 f

=

The value of series inductor:

(5)iQRL

=

In order to calculate the voltage at the AC load:

(6)1 2

4Ri ( maximum) V

4

V

The switch voltage can be calculated as:

Vs(maximum) = 3.562 V1 (7)

The current that flows in the choke inductor:

(8)1f 2

i

8 VI

4 R

The current that flows in an AC load can be calculated as:

(9)2

Ri Lf

4I I

2

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RiC3

C2

C1

L

Cs

RT

LT

CT

The voltage at the series-resonant capacitor:

(10)Ri(max imumC(max imum)

IV

2 fC

The voltage at the series-resonant inductor:

VL(maximum) = 2π fL (IRi (maximum)) (11)

The switch current can be obtained using:

(12)2

S(max imum) Lf

4I 1 I

2

The rms value of switch current as per below:

(13)2

S(rms) Lf

28I I

4

As, the effect on the switch conduction loss 2:

(14)rDs

2rDs S(rms)

P I

Optimum operation can only be achieved at optimumload resistance, Ri = Ropt.

Stage 2: Optimum operation of class E ZVS with attachedpiezoelectric transducerTheoretical calculation: In the earlier explanation, an AETsystem requires the piezoelectric transducer at thetransmitter unit to convert an electrical energy to pressurewave/sound wave/vibration energy before the energy can betransmitted via any medium wirelessly. In this part, anequivalent circuit of piezoelectric transducer is attached to theend of the inverter. Fig. 5 shows the typical equivalentelectrical circuit of piezoelectric transducer that used in thisstage. Details explanation regarding the modeling are stated by Abdullah et al.21 and Fabijanski and Lagoda22.The static capacitance of the piezoelectric transducers is

adopted from Abdullah et al.21 can be calculated as:

(15)T 233 0

S

K rC

h

The value of is assumed to be 635 as gained fromT33K

piezoelectric calculator developed by APC international, Ltd.The value of CT, LT and RPZT can be obtained using relevant

Fig. 5: Typical series-resonance equivalent circuit forpiezoelectric transducer

Fig. 6: Equivalent circuit of the matching circuit π1a

information from the manufacturer datasheet for piezoelectrictransducer. In this study, the piezoelectric transducer with apart number of MCUSD11A400B11RS from multicomp isapplied.

Stage 3: Optimum operation of class E ZVS with attachedpiezoelectric transducer with a matching impedanceTheoretical aspect: The power delivered to a load ismaximized when the load impedance if equal to source loadas stated in Svilainis and Dumbrava16 and Kazimierczuk andDariusz18. On the previous stage, the value of AC load ischanged, thus the load impedance is not equal to the sourceload. Therefore, it is required for matching circuits that provideimpedance transformation. Impedance transformation can beaccomplished whether by tapping the resonant capacitanceor resonant inductance as explained by Kazimierczuk andDariusz18. This study implemented resonant circuit π1a forthe design that shown in Fig. 6.

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Asian J. Sci. Res., 9 (4): 176-187, 2016

In order to obtain the components value of matchingcircuit, we will use the value of PZT load resistance, 173.06 Sas the value of Ri.

The series equivalent resistance, Rs can be obtained using:

(16)2 2

1 1S 2

Ri Ri

8 V VR 0.5768

4 P P

The reactance factor for the Ri-C3 and Rs-Cs equivalenttwo-terminal networks is:

(17)SCi

C3 S

XRq

X R

The relationship between Rs and Ri will develop thereactances of XCs and XC3:

(18)i i

S 22

i

C3

R RR

1 q R1

X

(19)C3 C3

CS 2

C32

i

X XX

1 X1 1q R

Rearrangement of Eq. 18 results in:

(20)i

S

R1

Rq =

Thus, by substituting the Eq. 20 into Eq. 17, resulting in:

(21)iS

S

RR 1

RCSX =

The DC input resistance of the class E inverter can beobtained through:

(22)1DC

1 1

V (1 D)[ (1 D)cos D sin D]R

I C tan ( d )sin D

Using Eq. 21 and 22, one can obtain:

(23)2

C2 S L2

1 ( 4)X R Q q

C 16

Thus, yielding:

(24)i i

C33 i

s

R R1X

C q R1

R

Based on Eq. 23 and 24, the value of C2 and C3 of matchingcircuit can be calculated.

RESULTS AND DISCUSSION

The analysis of class E ZVS inverter of Fig. 2 is carried outunder the following assumptions:

C The transistor and diode form an ideal switch whoseon-resistance is zero, off-resistance is infinity andswitching time is zero

C The choke inductance is high enough so that its accomponent is much lower than the DC component of theinput current

C The loaded frequency QL of the L-C-Ri series-resonantcircuit is high enough so that the current i through theresonant circuit is sinusoidal

Stage 1: Optimum operation of class E ZVSTheoretical result: In the first stage, the theoretical value ofeach component is found using the Eq. 1-13 based on thedesign specifications for Fig. 2 which is as follows: DC inputvoltage = 3.6 V, operating frequency = 416 kHz, power atthe AC load, PRi = 0.08 W, rDs = 0.12 S, Q = 10. The theoreticalvalue of the components in the inverter circuit is shown inTable 2.

Table 2: Theoretical value of inverter components for optimum operationComponent of the inverter ValuesRi 93.44 SC1 0.752 nFC 0.463 nFLf 1557.692 µhL 357.493 µhVRi(maximum) 3.867 VVS(maximum) 12.823 VIf 0.022 AIRi(maximum) 0.041 AVC(maximum) 34.210 VVL(maximum) 38.666 VIS(maximum) 0.064 APrDs 0.001 W

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Asian J. Sci. Res., 9 (4): 176-187, 2016

14.0

13.0

12.0

11.0

10.0

9.00

8.00

7.00

6.00

5.00

4.00

3.00

2.00

1.00

0.00

-1.00

1.001 1.002 1.003 1.004 1.005 1.006 1.007 1.008 1.009

vGS

vDS

1.000M

From_PICQ1 (D)

Fig. 7: Simulation model of optimum operation class E ZVS inverter

Fig. 8: Generation of PWM and ZVS condition fulfillment simulation results for optimum operation

Simulation results: In order to verify the working principle ofclass E ZVS inverter, the simulation model is developed usingthe Proteus software. A simulation model for this optimumoperation of class E ZVS along with the PWM generator forMOSFET IRF5852TR is shown in Fig. 7.

The simulation result of PWM generation as illustratedby square waveform is shown in Fig. 8. This is a stablewaveform with 5 Vp-p and 2.4 µS duration for 1 cycle. Thissignal will turn on and off the MOSFET thus drive thepiezoelectric transducer to perform the electrical signal topressure wave conversion at the operating frequency of

416 kHz. Figure 8 also shown the accomplishment of ZVScondition whereby the theoretically, there is no overlappingof switch current and voltage waveform during the switchingtime intervals, thus the switching losses are virtually zero,producing high efficiency. However, in simulation due someparasitic resistance value setting in the components, smalloverlapping occurred and this small disturbance is omitted inthis study. This simulation fulfilled the ZVS requirement asillustrated in Fig. 4, thus it can be concluded that the highefficiency of inverter performance is achieved in this particularsimulation.

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Asian J. Sci. Res., 9 (4): 176-187, 2016

v = 7.7 Vp-pAC load

4.50

4.00

3.50

3.00

2.50

2.00

1.50

1.00

500 M

0.00

-500 M

-1.00

-1.50

-2.00

-2.50

-3.00

-3.50

-4.00

1.000 1.001 1.002 1.003 1.004 1.005 1.006 1.007 1.008 1.009

M

Fig. 9: Output voltage waveform at AC load of the inverter

Table 3: Electrical equivalent circuit component’s valueComponents ValuesCS 2.136 nFCT 569.73 pFLT 257 µhRPZT 671.52 STotal impedance value of PZT 173.06 S

As our main attention in this study is to produce acoutput voltage, the Fig. 9 shows the voltage waveform thatmeasure at the AC load resistor. It can be seen that the circuitable to convert the dc source to an ac source that will betransferred wirelessly. From the calculation, the value ofVRi(maximum) is 3.867 V meanwhile in simulation, the value is3.85 V. In order to calculate the power, the basic equationof is implemented. The calculation gave us

2orms

outputi

VP

R

80 mW whereas, in the simulation, the power output voltageobtained is 79.3 mW.

Stage 2: Optimum operation of class E ZVS with attachedpiezoelectric transducerTheoretical calculation results: Table 3 displayed thetheoretical value of components for equivalent electricalcircuit for piezoelectric transducer. The value of staticcapacitance, CS is calculated from Eq. 15, whereas, for CT, LTand RPZT are obtained from manufacturer datasheet. Thismentioned value will be used in the simulation model thatbring together the class E ZVS inverter and the piezoelectrictransducer that supposed be as in the real applications.

Simulation results: After the extension of the optimumoperation class E ZVS inverter with the equivalent electricalcircuit of piezoelectric transducer, the changing in outputvoltage is expected due to the change of the total impedance.In the optimum operation section, only pure resistiveimpedance with the value of 93.442 S is applied. However, inthis stage, the equivalent electrical circuit of piezoelectrictransducer consists of inductor, capacitor, static capacitor andresistor that contributed to the overall variation in theimpedance value. Here, the previous ac load of class E ZVSinverter, 93.442 S is replaced with a complete of PZTtransducer equivalent circuit while the other components ofthe inverter are maintained as shown in Fig. 10. The totalimpedance value of PZT transducer equivalent circuit thatillustrated in Fig. 5 has been calculated and being used forfurther analysis.Figure 11 illustrates the ZVS condition of the simulation

result after the addition of PZT equivalent circuit. Thenon-overlapping of the switch time intervals still maintainedas before. However, small distortion occurred at the switchvoltage waveform due to mismatch problem. Here, thechanged of resulted waveform due to the addition of thePZT equivalent electrical circuit is expected. As comparedto Fig. 8 and 12 shows the output voltage that measuredat the total impedance of PZT transducer, not at the ACload of inverter as in previous measurements. From theobtained of vpeak = 3.85 V, in this stage, the simulationmodel only managed to get 42.83 mW that based on

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Asian J. Sci. Res., 9 (4): 176-187, 2016

11.0

10.0

9.00

8.00

7.00

6.00

5.00

4.00

3.00

2.00

1.00

0.00

-1.004.1400 4.141 4.142 4.1430 4.1440 4.1450 4.1460 4.1470 4.1480

vGS

vDS

M

Forn_PicQ (D)1

Fig. 10: Class E ZVS inverter attached to a simplified PZT equivalent circuit

Fig. 11: ZVS condition of the inverter with PZT attached

equation. With an efficiency of 53.53%, it is2orms

outputi

VP

R

moreover remote from the main objective. This majorreduction in the power output is mainly due to the mismatchof impedance for optimum operation. From the first stagesimulation result, we obtained the load for optimumoperation is 93.44 S, meanwhile in this stage; the totalimpedance of PZT transducer is 173.06 S. It is stated inKazimierczuk and Dariusz18 that if the value of loadresistance is higher than the optimum resistance, theinverter will operates in the non-optimum region. This will be improved using the impedance matching technique thatdescribed earlier.

Stage 3: Optimum operation of class E ZVS with attachedpiezoelectric transducer with a matching impedance circuitTheoretical calculation results: Some of important equationsare outlined as Eq. 16-24 in order to obtain the matchingimpedance circuit component's value. Table 4 displayed thevalue of relevant components of the resonant circuit π1a. Theother component values in Fig. 10 are maintained ascalculated earlier. Meanwhile, the total impedance value of173.6 S will be used as load resistance of the circuit. Thecircuit simulation model of stage 2 is modified to be similar asan equivalent circuit for π1a matching circuit as shown inFig. 6.

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Asian J. Sci. Res., 9 (4): 176-187, 2016

4.504.003.503.002.502.001.501.00

500 M0.00

-500 M-1.00-1.50-2.00-2.50-3.00-3.50-4.00

4.14104.1400 4.1420 4.1430 4.1440 4.1450 4.1460 4.1470 4.1480

vp-p = 7.7 V

RAC (1)

M

Fig. 12: Output voltage waveform at the PZT transducer

Fig. 13: Complete simulation model of transmitter unit

Table 4: Impedance circuit π1a component’s valueComponent ValuesC2 516.67 pFC3 2.0407 nFRi 173.06 S

Simulation results: From the component values in Table 4,the model of complete transmitter unit that consists of aninverter, matching impedance and piezoelectric equivalentelectrical circuit is simulated accordingly. Figure 13 displaysthe complete model of the simulation for the transmitter unit.The model observed to be less complicated due to thesimplified version of the piezoelectric transducer circuit ascompared to Fig. 5. Thus, the analysis and calculation will beshortened and easier for the beginners in this field.

In order to achieve high efficiency inverter, the natures ofclass E ZVS must be always satisfied. The non-overlappingtransition between the switch current and voltage waveformsmust be fulfilled all the time. This simulation result managedto satisfy the ZVS requirement as elaborated in Fig. 14. InFig. 14, the simulation result also shown that the ZVSwaveform is successfully recovered as resulted in the Fig. 8whereby the inverter operated in the optimum condition.Therefore, it can be concluded that the high efficiency inverterperformance is feasible and achievable.As our main concerns, the output power that produced at

the pzt transducer as a load of the transmitter unit. This powerwill transfer wirelessly to the receiving transducer at thereceiver unit. Figure 15 presents the output voltage that is

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Asian J. Sci. Res., 9 (4): 176-187, 2016

vGS

vDS

From_PICQ (D)1

14.0

13.0

12.0

11.0

10.0

9.00

8.00

7.00

6.00

5.00

4.00

3.00

2.00

1.00

0.00

-1.00

1.0140 1.0150 1.0160 1.0170 1.0180 1.0190 1.0200 1.0210 1.0220

M

6

5

4

3

2

1

0

-1

-2

-3

-4

-5

R2(2)

V = 10 Vp-p

1.0140 1.0150 1.0160 1.0170 1.0180 1.0190 1.0120 1.0210 1.0220

M

Fig. 14: ZVS waveform of complete transmitter unit simulation model

Fig. 15: Output voltage waveform of piezoelectric transducer load

measured at the PZT transducer. The inverter with completematching impedance circuit gives 10 V as peak-to-peakvoltage. With the PZT load impedance of 173.06 S, the outputpower obtained is 72.22 mW, which can be considered as abetter performance. This value is closer to 80.0 mW that beingaimed as the inverter output in this research. With the help ofan impedance matching circuit, the transmitter unit of thisAET system succeeded to gain 90.3% efficiency. This finding isaligned with the proposed efficiency as suggested by Ozeriand Shmilovitz4.

CONCLUSION

The performance of transmitter unit that consists ofclass E ZVS inverter and piezoelectric transducer at the

operating frequency of 416 kHz is studied, simulated usingProteus and compared. The simulation of performance foroptimum operation of class E ZVS inverter, followed by addingthe piezoelectric transducer and lastly is ending with theimpedance matching circuit provides the guideline for thosethat required such knowledge. The step-by-step and simpledesigns are illustrated and shown that the feasibility andcapability of inverter to achieve a high efficiency powerconversion that can be improved by add in the matchingimpedance to the existing circuit. The complete AETtransmitter unit managed to obtain 72.22 mW as the inverteroutput power. As the main target of the study, higher powerconversion efficiency at the transmitter unit of 90.3% isachieved and it is being calculated as the ratio of outputpower to input power. The high efficiency performance is

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Asian J. Sci. Res., 9 (4): 176-187, 2016

T33K

realized through the satisfaction of class E ZVS inverteroperation requirement throughout the simulation works.

NOMENCLATURE

ε0 = Vacuum permittivity (8.85×10G12 F mG1)r = Radial of piezoelectric surface (m)= Dielectric relative permittivity

h = Thickness of the piezoelectric (m)

ACKNOWLEDGMENTS

The authors would like to express an appreciation toMinistry Of Education Malaysia and Universiti TeknikalMalaysia Melaka (UTeM) for funding this research underRAGS/1/2014/TK0’3/FKEKK/B00062 grant.

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3. Sanni, A. and A. Vilches, 2013. Powering low-powerimplants using PZT transducer discs operated inthe radial mode. Smart Mater. Struct., Vol. 22. 10.1088/0964-1726/22/11/ 115005

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