International Journal of Emerging Technology in Computer Science & Electronics (IJETCSE)
ISSN: 0976-1353 Volume 13 Issue 1 –MARCH 2015.
 Stabilization Of Dc-Grid Voltage Fed Single-Phase
Bidirectional Converter Using Hybrid Energy
Source
Sathish Kumar B1, Jayamurugan M2, Dr. Sankar R3, Sridevi M4
1PG Scholar, Power Electronics and Drives,
2Associate Professor, Department of Electrical and Electronics Engineering,
3 Professor and Head, Department of Electrical and Electronics Engineering,
4Assistant Professor, Department of Electrical and Electronics Engineering
SKR Engineering College, Chennai, Tamil Nadu, India.
Abstract -Renewable power generation systems grow rapidly.
By nature, renewable power is not continuous and reliable. It
will be converted into dc form and buffered with energy storage
elements. This brings dc-driving opportunities for electric
appliance and equipment which are mostly supplied with dc
voltage sources. However, the distributed generation systems
require bidirectional converter to control the power flow
between dc bus and ac grid, and to regulate the dc bus to a
certain range of voltages. This paper presents dc-bus voltage
control with a single-phase bidirectional inverter for dc
distribution systems. The bidirectional inverter can fulfill both
grid connection and rectification modes with power factor
correction approaches. When the system is operated in
grid-connection mode, it needs a higher dc-bus voltage to
prevent dramatic voltage drop below the lower bound due to a
step dc load increase. And the system requires a lower dc-bus
voltage to extend the range of voltage swing in rectification
mode. In the literature, there are some power flow controls for
dc distribution system with constant-power loads, such as
general dc/dc converters. The bidirectional converter can fulfill
both grid connection and rectification with power factor
correction. This method can prevent dc-bus voltage from wide
variation and improve the availability of the dc distribution
systems without increasing dc-bus capacitance. The
performance of the proposed method is verified by simulation
using MATLAB/SIMLINK
Energy Agency estimated that, “to achieve universal access to
electricity, 70% of the rural areas that currently lack access
will need to be connected using mini-grid or off-grid
decentralized solutions” Mini-grids and other decentralized
solutions may be more attractive than large.
II. STATEMENT OF THE PROBLEM
A single-phase bidirectional inverter with two buck/boost
maximum power point trackers (MPPTs) for dc-distribution
applications. In a dc-distribution system, a bidirectional
inverter is required to control the power flow between dc bus
and ac grid, and to regulate the dc bus to a certain range of
voltages. , the MPPT topology is formed with buck and boost
converters to operate at the dc-bus voltage around 380 V,
reducing the voltage stress of its followed inverter. In the
proposed system without battery back-up can be employed for
renewable energy source for better stabilization to the
distribution system. The system can be tested with ac motor
load. Closed loop PID control is also provided to achieve the
desired output voltage. The Simulation is done with the help
of
MATLAB
Software
using
Simulink.
Index Terms—Dc-bus voltage control method, hybrid energy
source , SAM software of NREL, MPPT, incremental
conductance with integral voltage control technique,
bidirectional inverting current control method, improved
NDZ/MATLAB/ SIMLINK
I. INTRODUCTION
WORLDWIDE, about 1.5 billion people live without
Access to electricity. Without a concerted effort, the Number
of people denied from electricity supply is likely to sustain or
even increase . Extension of National Grids is Often
prohibited by high cost and non-feasible in isolated Rural
areas. Solutions to the limitations of rural Energy access
around the world require the use of both centralized and
decentralized power systems. In 2010, the International
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Fig 1. Block Diagram
International Journal of Emerging Technology in Computer Science & Electronics (IJETCSE)
ISSN: 0976-1353 Volume 13 Issue 1 –MARCH 2015.
III. SCOPE OF WORK PROCEDURE
A. Pv panel
This project will involve examining the national utility
network to identify potential unintentional dc-bus voltage
conditions; subsequently an equivalent of all the portions of
the network with potential for renewable energy source will
be produced. This equivalent prototype model of the network
containing the will then is used to develop a Mat lab/Simulink
model. The model will contain bus voltage control techniques
such as, buck boost converter, bidirectional converter and
PID controllers are performing major role of in this paper.
Also the power sharing between re renewable energy system
and the utility grid will be designed to provide maximum
reliability and maximum power transfer to the load.
(3)
Where
I0 = reverse saturation current (ampere)
n = diode ideality factor (1 for an ideal diode)
q = elementary charge
k = Boltzmann's constant
T = absolute temperature At 25°C, 𝐾𝑇𝑞≈0.0259 volt.
By Ohm's law, the current diverted through the shunt resistor
is
𝐼𝑆𝐻=𝑉𝑗𝑅𝑆𝐻
(4)
Where
RSH = shunt resistance.
Substituting these into the first equation produces the
characteristic equation of a solar cell, which relates solar cell
parameters to the output current and voltage
(a)
(b)
Fig 2. (a) Equivalent circuit of a solar cell (b) The schematic symbol of a
solar cell
A.1 modeling of pv panel
To understand the electronic behavior of a solar cell, it is
useful to create a model which is electrically equivalent, and
is based on discrete electrical components whose behavior is
well known. An ideal solar cell may be modeled by a current
source IL in parallel with a diode ID in practice no solar cell is
ideal, so a shunt resistance RSh and a series resistance Rs
component are added to the model. In Fig 2, the resulting
equivalent circuit of a solar cell is shown on the left. Also
shown, on the right, is the schematic representation of a solar
cell for use in circuit diagrams. From the equivalent circuit it
is evident that the current produced by the solar cell is equal to
that produced by the current source, minus that which flows
through the diode, minus that which flows through the shunt
resistor.
𝐼=𝐼𝐿−𝐼𝐷−𝐼𝑆𝐻
(1)
Where
I - output current
IL - photo generated current
ID - diode current
ISH - shunt current
The current through these elements is governed by the voltage
across them:
𝑉𝑗=𝑉+𝐼𝑅𝑆
(2)
Where
Vj = voltage across both diode and resistor
RSH V = voltage across the output terminals
I = output current RS = series resistance
By the Shockley diode equation, the current diverted through
the diode is:
MATLAB Simulink was used to model the PV Module by
constructing its equivalent circuit. Shockley diode equation
was used to exactly model the internal diode in the equivalent
circuit.
𝐼𝑑=𝐼𝑠𝑎𝑡 (𝑒𝑉𝑑𝑛𝑉𝑇−1)
(6)
Where
Id – Diode current
Isat– Reverse Saturation Current
Vd– The voltage across the diode
VT– The thermal voltage
n – The ideality factor, also known as the quality factor
Thermal Voltage is given by the equation
𝑉𝑇=𝐾𝑇𝑞
(7)
Where
q – Elementary charge
k – Boltzmann's constant
T – Absolute temperature
Sun power SPR-305-WHT Module for further proceedings
in this paper.
B. Wind energy
Wind power is the conversion of wind energy into a
useful form of energy, such as using wind turbines to
make electrical power Small-scale. Wind power is the name
given to wind generation systems with the capacity to produce
up to 50 kW of electrical power. Isolated communities that
may otherwise rely on diesel generators may use wind
turbines as an alternative. Individuals may purchase these
systems to reduce or eliminate their dependence on grid
electricity for economic reasons, or to reduce their carbon
footprint. Wind turbines have been used for household
electricity generation in conjunction with battery storage over
many decades in remote areas. Most small wind turbines
manufactured today are horizontal-axis, upwind machines
that have two or three blades. These blades are usually made
of a composite material, such as fiberglass. The turbine's
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International Journal of Emerging Technology in Computer Science & Electronics (IJETCSE)
ISSN: 0976-1353 Volume 13 Issue 1 –MARCH 2015.
frame is the structure onto which the rotor, generator, and tail
are attached. The amount of energy a turbine will produce is
determined primarily by the diameter of its rotor. The
diameter of the rotor defines its "swept area," or the quantity
of wind intercepted by the turbine. The tail keeps the turbine
facing into the wind.
is equal to output current
of the PV array; thus, the
output power of the PV array can be expressed as follows:
C. fuel energy source
A fuel
cell is
a
device
that
converts
the energy for fuel into electricity through
a
chemical
reaction with oxygen or another oxidizing agent.
Hydrogen produced from the steam methane reforming
of natural gas is the most common fuel, but for
greater
efficiency hydrocarbons can be used directly such as natural
gas and alcohols like methanol. Fuel cells are different
from batteries in that they require a continuous source of fuel
and oxygen/air to sustain the chemical reaction whereas in a
battery the chemicals present in the battery react with each
other to generate an electromotive force (emf). Fuel cells can
produce electricity continuously for as long as these inputs
are supplied
There are many types of fuel cells, but they all consist
a cathode an electrolyte that allows charges to move between
the two sides of the fuel cell. Electrons are drawn from the
anode to the cathode through an external circuit,
producing direct current electricity. As the main difference
among fuel cell types is the electrolyte, fuel cells are classified
by of electrolyte they use followed by the difference in startup
time ranging from 1 sec for PEMFC to 10 min for RSOFC.
Fuel cells come in a variety of sizes. Individual fuel cells
produce relatively small electrical potentials, about 0.7 volts,
so cells are "stacked", or placed in series, to increase the
voltage and meet an application's requirements. In addition to
electricity, fuel cells produce water, heat and, depending on
the fuel source, very small amounts of nitrogen dioxide and
other emissions. The energy efficiency of a fuel cell is
generally between 40–60%, or up to 85% efficient in
cogeneration if waste heat is captured for use.
Fig: 4.flow chart of perturbation and observation
tracking method
On the other hand, when the proposed MPPT is operated in
buck mode, inductor current
is equal to output current
; thus, the output power of the PV array can be expressed
as follows:
PPV buck (n) =
(n) ×
(8)
With this control algorithm, the controller tracks the
peak power by increasing or decreasing the duty ratio
periodically. In this studied PV inverter system, there is a
shared auxiliary power supply for the MPPTs and the
inverter. Because the switching frequencies of the MPPT (25
kHz) and the inverter (20 kHz) are different, their switching
noises might affect the accuracy of voltage and current
sampling, especially under high-power condition. To avoid
noise interference, the MPPTs are synchronized with the
inverter, and the controller will update the duty ratio of the
MPPT power stage every ten line cycles at the zero crossing
of the line voltage. Additionally, since the single-phase PV
inverter system has a twice line-frequency ripple voltage on
the dc bus, this synchronization approach can also eliminate
the ripple voltage effect and determine accurate output power
of the PV arrays. When the output power of the PV arrays can
be determined accurately, the proposed controller can track
the maximum power point precisely.
𝑃=𝑉×𝐼
(9)
Maximum power point is obtained when
𝜕𝐼𝜕𝑉=0 𝜕𝑃𝑃𝑉𝜕𝑉
𝑃𝑉=𝜕(𝑉𝑃𝑉×𝐼𝑃𝑉)𝜕𝑉𝑃𝑉=𝑉𝑃𝑉×𝜕𝐼𝑃𝑉𝜕𝑉𝑃𝑉+𝐼𝑃𝑉
(10)
𝜕 𝑃𝑃𝑉 𝜕 𝑉𝑃𝑉 > 0 if 𝐼𝑃𝑉 𝑉𝑃𝑉 > − 𝜕 𝐼𝑃𝑉 𝜕 𝑉𝑃𝑉 , on the left of
MPP;
(11)
𝜕 𝑃𝑃𝑉 𝜕 𝑉𝑃𝑉 = 0 if 𝐼𝑃𝑉 𝑉𝑃𝑉 = − 𝜕 𝐼𝑃𝑉 𝜕 𝑉𝑃𝑉 , at the MPP;
(12)
Fig 3.modelling of renewable energy source with bidirectional converter
IV PERTURBATION AND OBSERVATION
TRACKING METHOD
The MPPT controller tracks the maximum output power
of a PV array based on the perturbation and observation
tracking method. At the beginning, the controller will
determine the operation mode of the proposed MPPT. When
the MPPT is operated in boost mode, inductor current
𝜕 𝑃𝑃𝑉 𝜕 𝑉𝑃𝑉 < 0 if 𝐼𝑃𝑉 𝑉𝑃𝑉 < − 𝜕 𝐼𝑃𝑉 𝜕𝑉𝑃𝑉 , on the right of
MPP;
(13)
− 𝜕(𝑉𝑃𝑉 ×𝐼𝑃𝑉 ) 𝜕 𝑉𝑃𝑉 = 𝐼𝑃𝑉 + 𝑉𝑃𝑉 × 𝐼𝑃𝑉 𝑉𝑃𝑉 = 0 (13) 𝜕
𝐼𝑃𝑉 𝜕 𝑉𝑃𝑉 = − 𝐼𝑃𝑉 𝑉𝑃𝑉
(14)
The present value and the previous value of the solar module
voltage and current are used to calculate the values ∂I_PV of
and V_PV. If ∂V_PV=0 and I_PV=0, then the atmospheric
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International Journal of Emerging Technology in Computer Science & Electronics (IJETCSE)
ISSN: 0976-1353 Volume 13 Issue 1 –MARCH 2015.
conditions have not changed and the MPPT is still operating
at the MPP. If ∂V_PV=0and∂I_PV>0, the amount of
radiation has increased, raising the MPP voltage. This
requires the MPPT to increase the PV module operating
voltage to track the MPP. Otherwise, if ∂I_PV<0, the amount
of radiation has decreased, lowering the MPP voltage and
requires the MPPT to decrease the PV module operating
voltage. If (∂I_PV)/(∂V_PV )=-I_PV/V_PV , then
(∂P_PV)/(∂V_PV )>0, and the PV module operating point is
to the left of the MPP on the P-V curve. Thus, the PV module
voltage must be increased to reach the MPP. Similarly, if
(∂I_PV)/(∂V_PV )=-I_PV/V_PV, then (∂P_PV)/(∂V_PV )<0
and the PV module operating point lies to the right of the MPP
on the P-V curve, showing that the voltage must be reduced to
reach the MPP. In this work, a small marginal error could be
added to the maximum power conditions such that the MPP is
assumed to occur if
𝜕 𝐼𝑃𝑉 𝜕 𝑉𝑃𝑉 + 𝐼𝑃𝑉 𝑉𝑃𝑉 < 𝜀
(15)
Management scheme for achieving a linear relationship
between inductor current iL and dc-bus voltage vDC. The
operating range of the dc-bus voltage is 380±20V. When the
inverter is operated in grid-connection mode (selling power),
the operating range is from 380 to 400V, which ensures an
enough voltage level to accommodate abrupt dc load increase.
On the other hand, when the inverter is operated in
rectification mode (buying power),a lower dc-bus voltage
stands for a higher load power. Therefore, in rectification
mode, the system does not have extra high enough dc load
power to pull the dc-bus voltage below the lower bound. In
short, in grid-connection mode, dramatic voltage drop is the
major concern when loads are connected to the dc bus, while
in rectification mode, sudden voltage jump up is another
concern when loads are disconnected from the dc bus. Fig. 5
also shows the locus of the dc-bus voltage regulation
sequence in grid-connection mode. At time t0 , the inverter
stays operating point (vDC(n – 1), IA(n – 1)) on the load line.
V .DC-BUS VOLTAGE CONTROL
A diagram of the discussed three-phase bidirectional inverter
is shown in Fig. 3. It can fit to both delta-connected and
connected ac grid. In the designed prototype, Rennes’s
microchip RX62T is adopted for realizing the system
controller, which has 1.65 MIPS and includes floating-point
calculation and division. By considering wide inductance
variation [18], the inverter can be operated stably, especially
in high-current applications. Additionally, the system requires
dc-bus voltage control schemes balancing power flow. It
includes linear power management scheme, one line-cycle
regulation approach, and one-sixth line cycle regulation
approach. A stability analysis is presented to Support the
proposed regulation approaches
.
A. Linear Power Management Scheme
In a system design, the maximum PV power and the maximum
dc load power will not exceed the inverter capability. In our
developed system, both of the two maximum powers are
10kW. Fig. 8 shows an illustration of the proposed linear
power
Fig. 6. Illustration of the dc-bus voltage regulation for the dc distribution
system with power imbalance.
From the load line to point (vDC(n), IA(n – 1)) at t1 when
there
exists power imbalance. Then, the controller will update
current command IA(n – 1) with IA(n) at the beginning of the
nth line cycle, which will regulate dc-bus voltage to a new
set-point voltage vDC(n + 1) according to the linear power
management scheme. When the inverter reaches operating
point (vDC(n+1), IA(n)) at t2 , the controller will change
current command to IA(n + 1), maintaining dc-bus voltage
vDC for a new power balance. The system will be operated in
the new steady state after time t3. The proposed voltage
regulation approaches are based on the linear power
management scheme.
(16)
However, time tx 1 is unpredictable, and an initial guess is
made to tn−1 ; thus, new current command IA(n) for time
interval [tn , tn+1] can be determined based on previous
current IA(n – 1) as
(17)
Fig. 5. Illustration of a linear power management scheme for achieving a
linear relationship between inductor current iL and dc-bus voltage vDC .
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International Journal of Emerging Technology in Computer Science & Electronics (IJETCSE)
ISSN: 0976-1353 Volume 13 Issue 1 –MARCH 2015.
Where Tl is a line period, KDA is a mapping ratio between dc
Input current and ac output current, which is equal to
vDC/VAC
(VAC is the RMS value of ac grid voltage, typically 220 V),
and the initial current command IA(0) is equal to zero at the
system start-up. Once the system gets started, current
command IA(n – 1) will be updated cycle by cycle. Voltage
vDC(n + 1) is the set-point voltage, is If dc loads change
abruptly, the OLCRA cannot regulate dc bus voltage
immediately, and it needs a fast dynamic current control to
balance the power flow. In a three-phase inverter system, the
fast regulation interval is selected to be one-sixth line-cycle
according to each zero-crossing point of the three phase line
currents. Since the voltage ripple on the dc-bus is insignificant
in a three-phase inverter system with even 10% unbalanced
three-phase voltage sources, the voltage ripple can be ignored
in the control law derivation.
In a dc distribution system, the perturbation period of an
MPPT (typically 50–100 ms) is usually much longer than one
line period so that its power variation is very smooth and can
be even considered as a constant power over one line period.
Thus, only the dynamics due to the effect of dc loads is
analyzed. A dc load driven by a converter with tight
regulation behaves like negative dynamic impedance over a
wide bandwidth, and it will intend to regulate its input power
under dc-bus voltage variation. This effect can help the
proposed approaches to stabilize the dc-bus voltage
regulation. However, when there are positive resistive loads
connected to the dc bus, the total load power will vary with the
regulated voltage level. Thus, the proposed control
approaches, which regulate the dc bus to different voltage
levels according to the linear load line, will lead to dc-bus
voltage fluctuation or the stability problem. Assuming the
system was operated in the steady state, (Vdc,
IA), it is shifted to (Vdc + ˆ Vdc, IA + ˆIA). When there exists
a positive resistive load Rl , the control approaches will tune
the current command IA to balance the power flow.
.
(18)
Voltage variation Δvi includes two portions: one is the
variation ΔvDC(T ) between two consecutive one-sixth
cycles, and the other is the average difference ΔvDC(A)
between vDC(n+1) and the current operating point:.
Fig.7. Plot of current command variation ˆIA versus dc-bus voltage
variationˆ Vdc
(19)
The variation ΔvDC(T ) is caused by abrupt power imbalance,
of which the dc-bus voltage will deviate from the load line. By
adding this variation to the current command in one-sixth
cycle, the inverter can balance power flow substantially, but
dc-bus voltage vDC still does not reach its set-point yet. Thus,
the variation ΔvDC(A) is used for regulating vDC to voltage
vDC(n + 1) which has been determined at the beginning of the
nth line cycle, as shown in (9). With the compensation of
these two portions, the dc-bus voltage will come back to the
load line after power imbalance occurs at ty 1 (curve 2) or ty 2
(curve 3), as shown in Fig. 6. It can be observed that the
inverter controller updates current command IA(n + 1/6) at tn
+ Tl /6 after dc-bus Voltage drops abruptly at ty 1 (curve 2).
However, the inverter Controller will determine a wrong
current command due to the unpredictable time tY 1 , and the
dc-bus voltage will not be regulated to a correct voltage value
until next one-sixth line cycle, tn + 2Tl/6. If another power
imbalance occurs at ty 2 (curve 3), the same regulation
process will be conducted again. That is, the inverter will use
a correct current command IA (n + 3/6) to regulate the dc-bus
voltage to a set-point voltage.
The following relationship:
(20)
Where VS is the root-mean-square value of the line-to-line
grid voltage, and ˆp, ˆ Vdc, and ˆIA are the variations of
power, dc-bus voltage, and current command, respectively.
This equation can be also expressed as.
(21)
For simplicity, assuming the voltage variation ˆ V 2
dc is quite small, it can be ignored, which can lead to a
first-order approximation to the control (ˆIA) to output ( ˆ
Vdc) transfer function:
VI.STABILITY ANALYSIS
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International Journal of Emerging Technology in Computer Science & Electronics (IJETCSE)
ISSN: 0976-1353 Volume 13 Issue 1 –MARCH 2015.
(22)
By taking into account all of the parameters, voltage Vdc =
380V, Rl = 14.44 Ω under the maximum power 10kW, and
VS = 220V, Fig. 11 shows a plot of current command
variation IA versus dc-bus voltage variation ˆ Vdc with (21)
and (22). It can be observed that the approximation does not
penalize the accuracy of the original relationship shown in
(21). For the stability analysis in s-domain, (15) can be
denoted as plant, GP (s), and the controller, GC (s), is equal to
–CDC/T according to (8). The overall control block diagram
is shown in Fig. 12, where ki/(1 + sRC) stands for a low-pass
filter with 1/RC = 0.1 ωs and V ∗ dc is the voltage reference or
a desired voltage level at a particular power level. The loop
gain L(s) is expressed as follows:
(23)
Fig.9. Bode diagram of the loop gain L(s) bidirectional inverter
The maximum power rating of the bidirectional inverter is
10kW. However, the maximum output power of the existing
PV power simulator in our laboratory is only 7kW; thus, we
only show the measured waveforms with the maximum power
of 7 k Win the following discussion. Different power steps
will result in different voltage variations on dc bus. Thus, we
conducted various experiments to induce different voltage
variations of dc side. This can also verify a diversity of load
variations.
C. Output of the Proposed MPPT Algorithm
The effectiveness of the MPPT algorithm used in this project
has been evaluated based on varying the solar irradiance in
real time. From the fig 7, it is clearly seen that the Solar
Module starts to produce the maximum power that could be
extracted from the irradiance available at that point of time.
The MPPT block is triggered on at 1.5 seconds, to illustrate
the variation of power output of the panel with and without
MPPT.
Fig.8. Control block diagram of the proposed control
VII. RESULTS AND ANALYSES
The proposed dc-bus voltage control has been confirmed by
a 5-kW single-phase bidirectional inverter in a dc distribution
System. Based on the aforementioned specifications and
analyses, design of the power stage is summarized in Table II.
The range of dc-bus voltage is specified from 110 to 220V.
The nominal 1φ line-to-line voltage is 220Vrms and the line
frequency is 60 Hz. The inverter inductance varies from 2mH
to 300 μH per phase and the switching frequency is 20 kHz.
The power diodes are realized with silicon carbide, which
have no reverse-recovery time. A photograph of the designed
bidirectional inverter is shown in Fig. 12.
TABLE I
SYSTEM PARAMETERS OF
INVERTER
PROTOTYPE
732
THE
DESIGNED
International Journal of Emerging Technology in Computer Science & Electronics (IJETCSE)
ISSN: 0976-1353 Volume 13 Issue 1 –MARCH 2015.
Fig 14 bidirectional converter Simulink model form
VIII. SIMULINK PROSED SYSTEM WITH PLL
Have been discussed according to the aspects of dc-bus
voltage ripple and energy-storage capability. Experimental
results measured from the prototype inverter with a 5-kW
renewable energy simulator have verified the feasibility of
the proposed dc-bus voltage control approaches.
Fig 15. Load side rectification out put
Fig 11.load side Torque wave form
IX. CONCLUSION
Fig. 12. Photograph of the prototype of the designed single-phase
bidirectional inverter system.
Fig 13 buck boost converter output
Renewable energy sources are becoming increasingly
important recently with focus turning towards clean electricity
generation. In particular, photovoltaic (PV), wind energy and
fuel cell systems are is the most promising and attractive
renewable energy sources due to their low operational and
maintenance costs, pollution free power generation, long life
cycles, and noise free operation. The major Advantages of
proposed system is The Continuous regulation of dc bus
voltage, Controlled output voltage, High power conversion
can possible ,Both the rectification and as well as grid
connected mode can possible, Controlled output voltage.
A single-phase bidirectional converter with buck/boost
MPPTs has been designed and implemented. The converter
controls the power flow between dc bus and ac grid, and
regulates the dc bus to a certain range of voltages. An on-line
regulation mechanism according to the inductor current levels
has been proposed to balance power flow and enhance the
dynamic performance. Additionally, for power compensation
and islanding protection, the bi-directional inverter can shift
its current commands according to the specified power factor
at ac grid side. Simulated and experimental results obtained
from a 5 kW single-phase bi-directional. A droop regulation
mechanism according to the inductor current levels has been
proposed to balance the power flow and accommodate load
variation. Integration and operation of the overall inverter
system contributes to dc-distribution applications
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International Journal of Emerging Technology in Computer Science & Electronics (IJETCSE)
ISSN: 0976-1353 Volume 13 Issue 1 –MARCH 2015.
significantly. The simulation is done with the help of
MATLAB software.
ACKNOWLEDGMENT
The authors whole heartedly thank Mr. K.RAMADASS Chairman, Mrs. R.SUGANTHI - Director (Student’s Affair),
and Dr. DIVYA SATHISH - Director (Academics), and Dr.
M.SENTHIL KUMAR - Principal, SKR Engineering
College, for their unstinted support and encouragement for
carrying out the research work..
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