Design, Analysis and simulation of boost inverter for interfacing … · Fig.1:Block diagram for...

T.Teja Sreenu S.Md.Abdulmalik M.Poojitha Chowdary

Electrical and Electronics Engineering Electrical and Electronics Engineering Electrical and Electronics Engineering

KLUniversity, Vaddeswaram KLUniversity, Vaddeswaram KLuniversity, Vaddeswaram

Guntur, India Guntur, India Guntur, India

[email protected] [email protected] [email protected]

Abstract In this paper, we enhance the load requirement with the

help of the fuel cell. Basically, the output voltage of a fuel cell will

be less so here we use boost-inverter topology. This offers low

cost and compactness. To increase the efficiency, a battery is also

used because it can storage energy and it can also act as a to and

fro motion to protect the fuel cell from slow dynamics. The

single-phase boost inverter works as a V-mode control and

whereas the direct current to direct current and a bi-face

converter is Amp-mode control. The low-frequency current

which is rippled is supplied by the battery because it can reduce

the effects of such rippled current which is drawn directly from

the electric Cell. In this paper, we are applying this to stand alone

system. Index terms—Direct current to alternating current Boost

inverter, electric cell. Stand-alone system, withdraw unit.

I.INTRODUCTION

For the production of electricity generally we depend on

energy systems like solar pv and electric cells. These are to be

maintained for alternating current and direct current demands.

To use them for general purpose we need to maintain some

power electronic devices and also some chemical cell which

can satisfy the based on target applications. As the output

voltage of this chemical cell is less so we use supporters which

add the energy storage unit to reach the load requirement [1]-

[4]. Generally, the resultant of a chemical cell is in the form of

dc but we need ac power for the grid so boost inverters are

used. This converts the current and also step up it. To meet the

load requirement the fuel cells are arranged accordingly.

Based on the voltage-current characteristics of 72-cell PEM

chemical cell. they are various types of chemical cells and so

here we preferred PEMFC power module and the voltage

changes in between 40v and 69v depends on the output

ampere. Fuel cells works based on chemical process. It

converts chemical energy to electrical energy. chemical Cells

generate electricity in which energy saved in a chemial is

converts directly into Direct current through electrochemical

process. Because electrical energy is generated without buring

of fuel. Anode: generally the anode will be having negative

ions and the input that is given at the anode side is hydrogen

gas[6]. Cathode: the cathode side of the chemical is treated

with positive ions and the positive ions used in this process is

the oxygen gas. A catalyst is used in between and a

membrane which exchanges the proton is placed in between

the catalyst. Now the arrangement of chemical cell will be in

the following order: a membrane which exchanges the proton

will be in the middle and a catalyst will be be placed either

side of this and a anode is placed on one side and cathode is

placed on the another side. At first the hydrogen gas is

pumped through the anode. This hydrogen gad gets reacted

with catalyst and produces the positive ions and the remaining

hydrogen gas is send out through the another terminals

coming to cathode side when oxygen gas is sent to cathode the

gas gets reacted with the catalyst and releases the negative

ions the left over oxygen gas is also sent out through the

another outlet. The positive ions near the anode and the

negative ions near the cathode enters into the catalyst and

through the membrane which exchanges the proton when both

positive and negative ions get reacted. This reaction produces

the voltage from the chemical cell. The structure of the

catalyst will be rigid and porous. Because of this the surface of

the platinum which is coated on the its surface is totally

exposed to the pumped gases like hydrogen or oxygen.

The process of the chemical cell will be in the form of slow

dynamics and so the fuel cell must be taken as an account

during its design [7] [8] [9]. Because taking account during its

design will have higher priority role to draw the from the fuel

cell and so it exceeds the highest power, if this happens the

fuel call will fail to supply the required load power and get

damaged. So the conversion of power that is needed to be

Design, Analysis and simulation of boost inverter for interfacing fuel cell

system to single phase Grid

International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 1 (2017) © Research India Publications. http://www.ripublication.com

466

mailto:[email protected]



ensured that the power that is required should remain within

the last permitting limit.

The fuel cell includes two stages of power conditioning

systems for delivering ac power because it helps in the

drawbacks such as being heavy, high cost and less efficient

due to power conversion cascaded stages. To decrease these

inefficient, we use a boost dc-ac inverter which helps to

enhance the input voltage level and converts dc to ac

depending on duty cycles.

In a boost inverter, we use sliding mode controller instead of

double loop control because it helps to operate correctly under

any circumstances. As it is robust there will be steady state

response in ideal case.

Basically, there are two stages of fuel cells. They are single

stage fuel cell and two-stage fuel cell. There is less efficiency

in a single stage fuel cell when compared to two-stage fuel cell

I.e. nearly 10% range of power rating

[3][4][7][10][11][12][13][14]. Here we operate for stand-alone

fuel cell system by using the direct current to alternating

current inverter with the help of battery because it stores the

energy and the to and fro movement can be done as it helps

the chemical cell from its slow dynamics and remove the

distroted content in the current which destroys the efficiency

and lifetime of the fuel cell.

By this paper, the experimental results of grid system are

developed by using a one conversion stage only. The usage of

both direct current to alternating current inverter and a bi-

facial unit helps in solving the problems like less voltage

which will be varying, current harmonics and slow dynamics.

The work involved in a one conversion stage of energy is

boosting and inversion function which provides maximum

efficiency of power conversion. It also helps in reducing the

size of the converter and provides less in cost. Here the single

energy system is operated for stand-alone system.

Back-up Energy

Storage Unit

FC

Grid

Ac Load

Ac Bus

C1

C2

S2

S1

L1

L2

Boost Inverter

S3

S4

P1

P2

P3

P4

P5Unregulated

DC bus

Fig.1:Block diagram for the proposed boost inverter for interfacing

fuel cell system to single phase grid

II. Chemical cell system

A. About fuel cell system. Here the fuel cell is connected to the stand-alone system. From

the above block diagram, we can know the direction of power

flow between them. The circuit connection consists of two

energy converters; they are direct current to alternating current

inverter and the to and fro restored chemical unit are attach to

the unregulated dc bus to the boost dc-ac inverter. While the

resultant of the boost inverter is sent to the stand-alone

system. Here the system is a amp mode controller to and fro

converter with storage of battery so that it can support the

chemical cell, watt and boost inverter which controls the

voltage.

A fuel cell must modify by itself to vary the input to maintain

a particular energy operation. Volts and amperes limits must

be given by fuel cell manufactures and this also protect the

fuel cell from damages due to excessive loads. The design of

fuel cell should be in a order such that it can correctly react to

the appropriate situations to extends its life time. As fuel cell

working involves chemical reactions it can be used for longer

period of time.

Advantages of fuel cells are: Chemical cells are most efficient

when compared to others. By using this chemical cells we can


467

reduce the pollution effect on the environments. The only

chemicals used in this process are hydrogen and oxygen and

this doesn’t effect the society.

Disadvantages of Chemical cells are: H2 chemical Cells. To

make the hydrogen and oxygen atoms to operate separetly it

takes more maintains.

Lb2

Lf

I0

Idc Ifc

Batte

ry

I1

C4

IgSW

AC

Lo

ad

ILb1 ILb2

C1

C2

S2L1

L2 S3

S1

S4

Eg

pcc

Lg

Vg

S5

S6

C3

Back-up Unit

V0

V1

V2

I2

Lb1

Boost Inverter

FC

IL

Fig.2: Proposed boost inverter for interfacing fuel cell system to

single phase grid

B. Backup Energy Storage Unit Power energy is normally converted from many other

energy sources. Generally, battery is a system which helps in

the conversion of one form to the another form. As it can used

under any type of conditions a battery is popularly used fot the

life time applications in our daily lifes like for charging a

mobile those or a laptop etc…. basically in batteries there are

two types in which one type of battery can be used only onces

and the another type of battery can be used for many times

unless they can be refilled. The first one is called as a prime

battery and the second is called as a supporting battery. Even

the bi-facial energy storage unit is of two parts and they are: in

this the first one supports the bi-facial unit because it supports

the slow dynamics of a chemical cell. Second is to save the

chemical cell system because the bifacial unit provides a less

frequency alternating current that is needed from the direct to

alternating inverter working. As the batteries supply will be

having less frequency ampere distortion will results in having

low life time. The bi-facial unit compress for a ampere mode

controller of a to and fro converter and a battery as the power

saving one.

The above describes that if load increases both p1 and p2 will

give supply to satisfy the load condition and the process

involved in this is discharge to charge and to normal. When p3

decreases p1 supplies the required amount of electricity to

load and the rest of the electricity is stored in back up energy

storage unit and the process involved is charging to normal.

When the p1 is equal to p3 the way of supplying the electricity

will be normal. Here the backup energy unit helps in

increasing the total capacity of the system. In case of the

removal of the load instantly the energy from the chemical cell

can be restored and then saved in battery.

The alternating current part and parcel of the reference

ampere works in the removal of alternating current distrotion

into chemical cell energy modulator when the direct current

works with the slow dynamics of the fuel cell.

PI1

Back-up Unit

Idemand

ILb1,ref

ILb1Vb Vin

db

S6

S5

Vab Vb Vab Vb

ILb2,ref

LPF

Idc

Anti wind-up

Fig.3:Backup unit Control block diagram

Advantages of backup unit are:

Variety of types available

Low maintenance

No requirement for priming


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Self-discharge

High energy density

Disadvantages of backup unit:

Cost

Transportation

Ageing

Protection requirement

Immature knowledge

C. Boost inverter

As the output voltage of fuel cell is less and we need

more amount of voltage to satisfy load requirement. So, here

we use inverter to convert the dc to ac and each which

transmits for generating a single directional voltage higher

than the fuel cell volts with a changed duty cycle. Here we use

boost inverter to increase the current. The direct to alternatlve

current inverter consists of two to and fro direct to alternative

converters and the outputs of this are connected in series. Here

in this paper we used sliding mode control to operate the

output voltage. Here in the case of boost inverter the operation

used is double loop controller because of its accuracy process

to operate the each inverter which converter high range in the

working point. They are many advantages by this method

because this strategy method is depends on average time

which is continuous. As the boost inverter requires reference

voltage it is provided by the pq algorithm which controls both

the active power and the reactive power.

.

1 2 1 2

PR1PR1 PR2PR2 V1 Vin V1 Vin

V2 Vin V2 VinPR1PR1PR2PR2

Boost InverterV0,ref

V2,ref

V1,ref

Vdc

A0

Vin

V1

V2

I0

I0

Ic1,ref

Ic2,ref

IL1,ref

IL2,ref

I1

I2

VL1,ref

VL2,ref

Vin

Vin

V1

V2

d1

d2

S3

S1 S2

S4

Fig.4: Control block of boost inverter.

D. Operation of grid-connected boost inverter. The general

working of the system is to supply grid voltage and the use

of both fuel cell and battery is to support the required

amount of power in case of any requirement. There are

two ac sources in an inductor. The control over grid

connected is done through the boost inverter with a

double loop controller. At first a 29volts of dc is sent

through the boost inverter and then that dc is sent to the

boost inverter where 29volts will be increased to 230volts.

As the fuel cell cant supply continuously a lead acid battery

is also used to satisfy the load condition if there is any

difference in the supply. The battery used here is a

bidirectional which can either store the energy or else feed

the voltage.

KK w0 s w0 s

KK

w0 s w0 s

w0 s w0 s

w0 s w0 s

K w0 s

K

w0 s

w0 s

w0 s

1

XX

XX

XX

XX

PI4PI4 1/sPI4 1/s

1/2

PI2PI2 sinsin

XX

αβ/dq

1/2

PI3PI3

1

Orthogonal

system generation

Vg

Ig

Vα

Vβ Iα

Iβ

Pmeas

Qmeas

Vpp

V0,ref

dVpp

ω0 0

ω0l

θ

θ0

P*

Q*

PQ Control

Fig.5: Reference voltage of PQ control algorithm block diagram

Each dc-ac converter output and total output results are describe


469

III.SIMULATION RESULTS

Simulation Results of proposed boost inverter

Time[sec]

Vo

lta

ge

[V

]

Fig.6:Output voltage waveform of Boost inverter

Time[sec]

Cu

rre

nt[A

]

Fig.7:Output Current of Boost inverter

Time[sec]

P[w

]

Fig.8:Active power Waveform

Time[sec]

Q[w

]

Fig.9:Reactive power waveform


470

CONCLUSION

• single phase dynamic model for grid connected mode

of proton exchange membrane cell (PEMC) was

developed in MATLAB SIMULINK. A single phase

inverter has been designed and it is connected in

between PEMC to GRID/STAND ALONE

SYSTEM. This system is connected to grid in one of

side and other side is power by DC source. DC

source is comprised by internal combination of fuel

cell. The control strategy for controlling of phase

angle for single phase inverter is decoupled PQ.

REFERENCES

1.P.Saanchis ,A.Ursaea, E.gubia, and L.Marroyo,”Boost DC-AC inverter:A

new control

strategy,”IEEE Trans. Power Electron.,vol.20,no.2,pp.343-353,mar.2005.

2.R.O.Caceres and I.Baarbi, “A boost DC-AC converter:Analysis, design, and

experiment,”

IEEE Trans.Power Electron., vol.14,no.1,pp.134-141.jan.1999.

3.NP-series lead acidn battery

manual,(2007).[Online].Available:http://www.yuasa-battery.co.uk.

4.A.Josen,”Fundamental of battery Dynamics,”J.power

sources,vol.154,pp.530-538,Mar.2006

.

5.Horizon fuel cell Technology, H-series PEMFC system user guide

(2010).[online]. Available: http://www.horizonfuelcell.com .

6.”Fundamental of battery dynamics” published in journal of power sources

154(2):530-538.March 2006.

7.”A buck-boost Dc-Ac converter: operation, analysis, and control” published

in Power Electronics Congress,1998.CIEP 98.VI IEEE International.

8.P.Thounthong,B.Davat, S. Rael, and P. Sethakul,”Fuel cell high power

applications,” IEEE Ind. Electron. Mag., vol. 3, no. 1, pp. 32-46,Mar. 2009

.


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