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
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
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 1 (2017) © Research India Publications. http://www.ripublication.com
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
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 1 (2017) © Research India Publications. http://www.ripublication.com
468
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
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 1 (2017) © Research India Publications. http://www.ripublication.com
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
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 1 (2017) © Research India Publications. http://www.ripublication.com
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.
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