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International Journal of Science Engineering and Advance
Technology, IJSEAT, Vol. 4, Issue 7
ISSN 2321-6905
July -2016
www.ijseat.com Page 322
Control of the Output Voltage of the PV System Based DC-DC
Boost Converter Using Arduino microcontroller
1Jawad Radhi Mahmood , 2Nasir Hussein Selman
1Electrical Engineering Department, College of Engineering, Basrah University, Iraq
2Communication Engineering Department, Technical Engineering College/Najaf,
Al-Furat Al-Awsat Technical University, Iraq
Abstract-The main object of this paper is to design
and implement a DC-to-DC boost converter that
regulates output voltage to a desired value and can be
used in Photovoltaic system appliances or other
unregulated sources. To regulate the output voltage of
the boost, a feedback loop with Proportional-Integral-
Differentiator (PID) controller is employed. The duty
cycle is controlled to produce constant output voltage
using voltage mode control technique. A simulation of
the boost converter is done in MATLAB/Simulink. Also
a practical implementation with the help of Arduino
microcontroller is confirmed the validity of the control
algorithm. Simulation and practical results have been
proven that the proposed design is able to produce a
regulated output voltage successfully against variation
of input voltage and load.
Index Terms- Photovoltaic (PV) cell, boost
converter, voltage control mode, PID controller,
microcontroller and digital PWM generation.
I. INTRODUCTION
The world trend nowadays is to use sustainable and
renewable energy sources such as PV cells which require
power electronic devices. The output voltage of the solar
panels is relatively low and considerably unregulated
since it is depending on sun insolation and temperature.
Therefore, the low and fluctuating PV system voltage is
required to be boosted to a higher and regulated voltage.
A DC to DC boost converter with feedback control loop
is commonly employed to control the voltage of the PV
system to the desired and constant level suitable for
several domestic applications [1].
The objectives of this paper can be summarized by:
i) Analyzing the continuous conduction mode (CCM) of
DC-DC boost converter and designing their components
under this operating mode at 10 kHz switching frequency
for a PV system having a maximum power rating of 2
kW.
ii) Testing the response of the boost converter with and
without PID controller using MATLAB/ Simulink under
various operating conditions.
iii) Implementing digital PID controller system using
Arduino UNO microcontroller and examine the
hardware implementation under the same simulation
conditions for comparison study.
II. BASIC OPERATION OF A DC-DC BOOST CONVERTER
A DC-DC boost converter is a type of power converter
with an output voltage greater than its input voltage.
Generally, the basic operation of the boost converter is
performed by a combination of four elements which
includes inductor (L), controlled electronic switch
(usually MOSFET or IGBT), diode, and an output
capacitor (C). The basic schematic circuit of a boost
converter is given in Fig. 1[2].
Fig. 1: Basic circuit of the boost converter
In the boost converter, the output voltage is stepped
up and controlled by adjusting the ON/OFF time
durations of the control signal which is applied to the
controlled switch (SW). The boost converter runs in two
distinct states [3].
-State 1: in this state, SW is in ON-state (closed). The
boost circuit will be divided into two loops as shown in
Fig. 2-a. At the first loop (left), the input current flows
through the inductor and the SW. During this state, the
inductor current (IL) will rise and the energy stored in it
and not supplied to the load. The inductor voltage (VL)
represents input voltage (Vin). Under this state, the diode
is OFF (reverse biased) and the capacitor is in
discharging mode to supply current to the load (right
loop).
-State 2: here the SW is in OFF state (Open). The
current flows to the capacitor and load through the diode
as depicted in Fig. 2-b. The energy stored in the inductor
International Journal of Science Engineering and Advance
Technology, IJSEAT, Vol. 4, Issue 7
ISSN 2321-6905
July -2016
www.ijseat.com Page 323
during state1 is now transferred to the load together with
that from the input source. The current of the inductor
continues in decay up till the MOSFET is fired again in
the following period. During this period, (VL=Vin-Vout).
(a)
(b)
Fig. 2: Two circuit states of the boost converter
(a) ON state MOSFET , (b) OFF state MOSFET
III. OPERATION MODES OF THE BOOST CONVERTER
There are two modes of operation for the boost
converters. These modes are continuous conduction
mode (CCM) and discontinuous conduction mode
(DCM) [3]. Only CCM mode is described and adopted in
this work because it has best performance and easy
design. Analysis of the circuit under CCM has been
carried out assuming ideal boost converter. Also the
capacitor and inductor are assumed to be lossless.
In CCM mode, ILflows continuously and dose not
reach to zero as given in Fig. 3.
Fig. 3: Current and voltage waveforms of the boost
converter (CCM)
The relation that relates the output voltage (Vout) and
input voltage (Vin) in CCM is given by following
equation [4]:
inout V
D
V
11
(1)
Where, Drepresents duty cycle which refers to the
ratio of ON-time of the MOSFET to the total switching
time (T). The D takes values between zero and one (zero
refers to the MOSFET is always OFF and one refers to
the MOSFET is always ON). Thus, Eq. (1) shows that
Vout is always greater than Vin and it increases with an
increase of D. Theoretically, Vout goes into infinity as D
approaches to one but practically goes to zero. In the
practical boost converter, the duty cycle cannot equal to
one because the inductor would become saturated and
the input voltage would be shorted [5]. As mentioned in
[6], an approximate practical limits for boost converter
duty cycle in CCM ranges from 20% to 80%.
IV. PROPOSED SYSTEM AND COMPONENTS SELECTION
Before choosing the components of the DC-DC boost
converter, The PV system specifications that required to
stepped up and regulating its voltage must be studied.
The PV system is consisting of eight SOLIMPEKS PV
modules which are connected in series as depicted in Fig.
4.
Fig. 4: Pictorial image of eight series SOLIMPEKS PV
modules
International Journal of Science Engineering and Advance
Technology, IJSEAT, Vol. 4, Issue 7
ISSN 2321-6905
July -2016
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The specifications of the SOLIMPEKS PV module at
STC (1kW/m2, 25˚C) are given in Table1.
Table 1: SOLIMPEKS PV Module Specifications at
STC (1kW/m2, 250C)
Thus, the whole PV system which will be studied in
this paper has the following specifications at STC:
- Maximum Power (Pmax) = 240 × 8 = 1920 W,
- Vm= 30.72 × 8= 245.76 V and VOC = 36.6 × 8 = 292.8
V,
- Im= 7.81 A and ISC = 8.36 A
All components of the DC-DC boost converter should
meet the specifications of the PV system mentioned
above and the parameters tabulated in Table 2.
Table 2: Specifications of the proposed DC-DC boost
converter
The following subsections provide an outline of the
considerations for designing boost converter
components.
A. Power MOSFET and Diode Switches Selection
The appropriate power MOSFET and diode rating
selection are based on the specifications of the PV
system. The main considerations for the selection are [2]:
i- The reverse breakdown voltage rating must be greater
than the maximum input and output voltages.
ii- The rated average forward current of the MOSFET
should be greater than the boost input current while the
rated average forward current of the diode must greater
than the load current.
iii- For better efficiency, choose the diode with quick
switching characteristic, low parasitic capacitance and
low forward voltage drop (VF). A Schottky diode is
recommended because of its low forward drop.
B. Duty Cycle (D)
The duty cycle depends on the Vin and Vout of the boost
converter and can be obtained from equation (1) as:
out
in
V
V
D 1
(2)
Since Vout is constant at desired voltage of 325V, a duty
cycle changes with the value of its input voltage as
follows:
- The minimum duty cycle (Dmin) at maximum input
voltage (Vin-max ≈ 250V),
23.0
325
250
11 max
min
out
in
V
V
D
(3)
- The maximum duty cycle (Dmax) at minimum input
voltage (Vin-min ≈ 180V),
45.0
325
180
11 min
max
out
in
V
V
D
(4)
C. Switching Frequency Selection
In order to minimize the inductor size and reduce
distortion, switching frequency (fsw) selection must be
high sufficiency, in the range of 2 kHz-100 kHz.
However higher switching frequencies lead to high
switching losses [4]. Compromising between the two
factors must be considered when choosing an operating
frequency and inductor for a DC-DC converter. The
value of fsw has been selected as 10 kHz.
D.Inductor Selection
The inductor selection is the most important factor
because it determines the inductor current ripple (ΔIL).
This ripple is proportional inversely with the value of L
and is presented by [3]:
Lf DV
L
DTV
I
sw
inin
L
(5)
To operate the boost converter in CCM, the critical
inductance value (Lcrit) is given by:
Lsw
in
crit If DV
L
(6)
The selection of Lcrit must be greater than the calculated
value. Any value less than Lcrit will lead to operate the
boost converter in DCM.
The average inductor current (IL) is given by:
)1( D
I
Iout
L
(7)
ILis at maximum value when the input voltage is
minimum (i.e. when Dmax=0.45), and the maximum
output current (Iout) is about 6A. Thus the maximum
r.m.s. value of ILis:
International Journal of Science Engineering and Advance
Technology, IJSEAT, Vol. 4, Issue 7
ISSN 2321-6905
July -2016
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AIL11
)45.01(
6
For CCM operation, the peak inductor current (ILpeak) can
be given by
2L
LLpeak I
II
(8)
The approximate value of ΔILis 2.2A based on the
assumption of 20% ripple input current. Therefore,
ILpeak ≈ 12.1A.
Substitute all values in equation (6) to find Lcrit, which is
equal to (3.7 mH ).
The practical design of the inductor is based on the
value of critical inductance that is calculated and
maximum amount of current that is carried. A toroidal
ferrite core is suitable selection for the design.
E. Output Capacitor Selection
The output boost converter capacitor (Cout) is greatly
affected by the output voltage ripple (ΔVout). The output
voltage peak-to-peak ripple can be determined by [2]:
outsw
out
out Cf DI
V
(9)
The capacitor value can be determined from:
outsw
out
out Vf DI
C
(10)
The selection of Cout must be higher than the calculated
value to make sure that the converter’s output voltage
ripple remains within the specific range and its
equivalent series resistance (ESR) should be low. ESR
can be minimized by connecting a number of capacitors
in parallel.
Substitute the values of Iout,fsw, and ∆Vout into Equation
(10), the capacitance value is about 166 uF. An
appropriate standard capacitor is chosen greater than this
calculated value.
Table 3 summarized the calculated parameters and
selected components of the proposed boost converter
based on the equations and considerations mentioned
previously.
Table 3: Boost converter calculated parameters and
selected components
V. CONTROL SCHEMES OF DC-DC CONVERTERS
To regulate the output voltage of the DC-to-DC
converters, feedback loop is employed for adjusting duty
cycle and obtained the desired voltage output. The most
common control schemes are: Voltage Mode Control
(VMC) and Current Mode Control (CMC) [3,6,7]. Other
hybrid designs are deduced from combinations of these
controls. Here, VMC control strategy has been adopted
because CMC has a certain complexities.
The schematic diagram of a VMC is shown in Fig. 5
[3]. Vout of the boost converter is observed through a
voltage divider (R1and R2) that feeds a fraction of the
output voltage back and creating a closed-loop system.
The feedback voltage (Vfb) and the reference voltage
(Vref) are entered into the error amplifier to generate the
error signal (Ve). The generated signal (Ve) is then fed to
the compensator (such as PID controller) to produce
control voltage (Vc). This control voltage signal is
compared with a saw-tooth wave to produce a
controllable duty cycle which is called pulse width
modulation (PWM) signal, that drives the MOSFET[4,
6].
(a)
(b)
Fig. 5: VMC of the boost converter
(a) Boost converter and Control block
(b) Voltage control block
When Vout of the converter is increased, Vcis also
increased which causes the duty cycle of the MOSFET to
decrease (less pulse width) as shown in Fig. 6. The
changing in duty cycle will adjust Vout of the boost
converter by reducing error to zero and make the output
voltage follow the reference value.
International Journal of Science Engineering and Advance
Technology, IJSEAT, Vol. 4, Issue 7
ISSN 2321-6905
July -2016
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Fig. 6: Generation of PWM signal
VI. PID CONTROLLERS
The PID controllers are feed-back control loop technique
that is generally employed in controlling the industrial
equipments. It consists of three terms (proportional "Kp",
integral "Ki" and derivative "Kd"). The block-diagram of
the PID controller is shown in Fig. 7.
Fig. 7: PID controller block diagram
The aim of the PID controller is to make the actual
output ,Vout(t), of the plant (boost converter), follows the
reference signal, Vref(t), by its attempting to reduce the
error signal, Ve(t), where:
Ve(t) = Vref(t) - Vout(t)
(11)
The controlled output variable, Vc(t), is adjusted to the
new value according to the following expression:
dt tdV
KdVKtVKtV e
d
t
eiepc )(
)()()(
0
(12)
Where:
t: Current time, and
: Integration variable; its value
from time zero to the current t[8].
Although there are only three parameters associated
with the PID controller, but the tuning of them to the
optimal value is a complex problem. There are different
methods are adopted to find the values of these
parameters, called PID tuning. If the PID controller
parameters are selected incorrectly, the controlled
process will become unsatisfactory or unstable.
The Ziegler-Nichols method [9] is widely used to tune
the parameters of the PID controller experimentally.
First, set Kiand Kdto zero and the gain Kpincrease until
the system reaches to a stationary oscillation. After that
Kp,Kiand Kdparameters will calculated through
determining the gain (Ku) and the time of the oscillation
(Tu). The parameters are calculated depending on the
controller type, and can be found in the Table 4.
Table 4: Ziegler-Nichols method [9]
A PID controller block has been introduced in
MATLAB Simulink library as described in Fig. 8. The
block parameters can be tuned automatically using PID
tuner to achieve an acceptable response for the simulink
control design. In Some applications, only one or two
terms of the PID controller are used to get the proper
control for the system. This is done by making the other
terms to zero. In this case, a PID controller is calling (PI,
PD, P or I) controller.
Fig. 8: PID MATLAB Simulink block
VII. BOOST CONVERTER SIMULATION
The DC-DC boost model has been simulated in
MATLAB (illustrated in Fig. 9) based on the
specifications and calculated values listed in the Tables
(1-3).
Fig. 9: Complete simulink model of the boost converters
The boost circuit has been connected to a PV system
which is pictured in details in the mathematical simulink
model of Fig 10.
International Journal of Science Engineering and Advance
Technology, IJSEAT, Vol. 4, Issue 7
ISSN 2321-6905
July -2016
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Fig. 10: Simulink mathematical model of PV system
In order to verify the performance of this model, many
cases have been tested such as load changes and input
voltage changes, with and without PID controller.
A. Open Loop System Model (Without Controller)
Open-loop system can not be used in practical
applications. It has been simulated to test the correct
selection of the system components and satisfy the boost
characteristics that have been calculated previously,
more than anything else. The system has been studied
when a 325V/1900 W resistive load was applied on it.
The PV system voltage at STC is about 250V. To
produce 325V, duty ratio of the PWM signal applied to
the MOSFET switch gate is (0.23).
The simulation results of the PV system voltage (Vin)
and output voltage of the boost converter (Vout) are
cleared in Fig. 11. The output voltage ripple (ΔVout) of
the converter is (0.4V) which falls within the allowable
range (≤ 0.5% Vout). This gives an indication that the
capacitor that has been selected is suitable for the
system.
Fig. 11: Boost converterinput and output voltagesat
D=0.23
The inductor current (IL) and output current (Iout) are
shown in Fig. 12. The inductor current ripple (ΔIL) of the
converter is (1.9 A) which falls within the requirements
range, (≤ 20% IL). This means that the inductor value
selection was correct.
Fig. 12: Boost converter Input and output current at
D=0.23
B. Closed Loop System
In practical applications a closed-loop system is used.
The system is tested to examine the design and provide a
constant output voltage with the help of PID controller.
The system has been studied for the following cases:
i- Variable input voltage and constant load
The response of the closed loop system has been tested,
first, at the constant load and variable input voltage (the
input voltage variation is intended to reflect the effect of
temperature and insolation variations (Fig. 13a & b) on
the output voltage of the solar system).
(a)
(b)
Fig. 13: Step changes in weather conditions
a) Operating temperature, b) Solar insolation
The output voltage response and the changes in the
input voltage have been pictured in Fig. 14. The figure
shows that the output voltage is to some extent constant
and equals 325V. After each disturbance in the input
voltage (increase or decrease), the controller senses these
changes and respond to them after comparing them with
the reference voltage. The output voltage quickly reaches
the steady state value (after 0.1s from the instant of
disturbance creation). This means that the PID controller
International Journal of Science Engineering and Advance
Technology, IJSEAT, Vol. 4, Issue 7
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July -2016
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has an effectiveness response during the adopted
changes.
Fig. 14: Response of Vout of closed loop system at
constant load and Variable Vin
ii- Constant input voltage and variable load
The designed closed loop PID controller also has been
tested under load step changes while the PV system
voltage remains constant at STC. As it is clear from Fig.
15, the load changes have been issued at 0.2s interval. It
is obvious that the PID controller response depends on
the amount of changes in the load and the output voltage
almost matches the desired value of 325V.
Fig. 15: Response of Vout of closed loop system at
different loads
VIII. BOOST CONVERTER HARDWARE IMPLEMENTATION
After being verified the required DC-to-DC boost
converter by the MATLAB program, it has been
implemented practically. To obtain a constant output
voltage of the boost converter, voltage and/or current
feedback loops must be used. The duty cycle is increased
or decreased according to the state of the input voltage
using PWM method. Modern controllable equipments
use microcontroller to achieve PWM although simple
analog circuit can be used. Digital controllers have
numerous preferable features as compared to the analog
controllers. These positive features include program-
ability, adaptive, less sensitivity to the environment
variations, capable to achieve complex control
techniques and require few extra components. Beside
that, the changing in the gain in analog control circuit is
performed by adjusting the hardware components which
is considered hard solution.
In order to implement a PWM signal generator for
controlling the duty cycle of the MOSFET switch using a
microcontroller, the following items should be covered.
- PWM concept and how can be generated using Arduino
microcontroller.
- How to measure DC voltage by microcontroller.
A. PWM Generation Using Microcontroller
A PWM is a well known technique to control the
output voltage by adjusting on-time of the pulse width
(duty cycle) of analog signal. The frequency of PWM
represents the amount of time taken by PWM to
complete one cycle. In order to produce variable analog
values, the pulse width can be changed from 0% to
100%. Figure 16 displays the PWM output for different
duty cycle. The distance between any two successive red
lines represent the time of one cycle and the reciprocal
this time interval gives the switching frequency of the
PWM output. To effectively use the PWM function of
the Arduino, its timer function should be concerned.
Fig. 16: Various PWM (Various duty cycles)
The ATmega328P datasheet gives a detailed
description of the PWM timers [10]. Here, a simple
explanation for the use of timers.
There are three timers in the ATmega328P chip, and
they can be configured in a different ways to perform
different purpose. They are described as follow:
i- Timer 0: this timer is used for PWM outputs on pins 5
and 6. It has 8-bit size and its maximum counting time is
255.
ii- Timer 1: this timer is used for PWM outputs on pins 9
and 10. This timer has additional modes to supports
timing results up to 16 bits. Thus, it can reach a
maximum value of 65535.
iii- Timer 2: this timer is used for PWM outputs on pins
3 and 11. The size of this timer is the same of timer 0 but
has different pre-scale values from the Timer 0 and
Timer 1.
The two outputs of each timer have the same frequency
but differ in duty cycles (depending on the respective
output compare register). If the timer current count
reaches ad exceeds the compare register set value, the
International Journal of Science Engineering and Advance
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corresponding output is toggled. Each timer has pre-scale
factors (such as 1, 8, 64, 256, or 1024) to set the time
intervals between successive counting. The timer clock
frequency represents the ratio of Arduino clock
frequency (16 MHz) and pre-scale factor.
Two registers are used to adjust the output of each
timer. They are called Timer/Counter Control Registers,
written acronym TCCRnA and TCCRnB, and the value
of xis the timer number (0,1,2). These two registers hold
the following groups of bits that control the operation of
the registers, frequency, and also pre-scalar values:
Waveform Generation Mode bits (WGM): These bits
control the supported mode of the timer. These bits are
split between the Registers TCCRxA and TCCRxB.
Clock Select bits (CS): These bits control pre-scale
value.
Compare Match Output Mode bits (COMxA and
COMxB): These bits enable/disable/invert outputs A
and B.
There two PWM modes of the operation for the timer
(fast mode and phase correct mode). In this work, fast
PWM mode is used so it will be explained briefly here
only.
In the fast mode PWM mode this PWM mode, the
timer repeatedly counts from 0 to 255. The output turns
ON (HIGH) when the timer is at 0, and turns OFF
(LOW) when the timer reaches the output compare
register value (OCRxX). Higher OCRxX value means
the higher duty cycle. The diagram given in Fig. 17
shows the outputs values for the two registers OCRxA
and OCRxB. Note that both outputs, OCxA and OCxB,
have the same frequency with different duty cycle.
Fig. 17: Outputs values for the two registers OCRxA and
OCRxB (Fast PWM Mode)
B. DC Voltage Measurement
As the microcontroller's analog input pin is restricted
to 5V maximum, a voltage divider is required to step
down the voltage to the range of the microcontroller's
analog inputs as given in Fig. 18. The values of resistors
are selected so that the current flowing through them is
small and cause small power losses (Ploss= I2R).
The suitable resistors values of the voltage divider
that used to step down a 325 V voltage are; R1 = 1MΩ
and R2= 12 kΩ. Thus, the calculated voltage value that
stepped by voltage divider is 3.85 V which is appropriate
for microcontroller analog input pins (ATmega328P chip
has six analog input pins "A0-A5"). These pins convert
analog voltage to suitable digital value (0-1023). The
analog value of voltage is read by Arduino
microcontroller using (analogRead) function that covers
the range 0 to 1023.
The step increment can be found as:
step increment=1ADC = 5/1024 = 0.00488 V
Vin = Vout*(R1+R2)/R2
= ADC reading * 0.00488 * (1012kΩ/12kΩ)
This marks that a 1023 reading corresponds to an input
voltage of 5V. In practical, 5V may not obtain always
from the Arduino, so the voltage between the 5V pin and
ground pin of Arduino must be measured first during
calibration by using a voltmeter, and use
1ADC=measured voltage/1024 instead of (5/1024).
The microcontroller changes the duty cycle according
to the reading of analog value of the feedback voltage (at
its analog input pins). The modification of the duty cycle
follows the relation derived in CCM (D=1- Vin/Vout).
Fig. 18: The boost converter circuit and its control
IX. BOOST CONVERTER HARDWARE IMPLEMENTATION
Figure 19 shows a photographic image of a practical
boost converter circuit including control stage. The
control stage contains Arduino UNO microcontroller
(ATmega328P), optocoupler, IR2110 driver, current
sensor, and voltage divider.
Fig. 19: Pictorial image of the experimental DC-DC
boost converter circuit
Optocoupler offers electrical isolation between the
microcontroller and the power circuit. It also protects the
microcontroller from any reverse currents flowing from
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the power circuit. Figure 20 shows the schematic
diagram of the 6N137 optocoupler.
Fig. 20: 6N137 optocoupler schematic diagram
The output PWM signal of the 6N137 optocoupler is
applied to the power MOSFET switches in the boost
power stage via an IR2110 gate driver. The PWM signal
will be fed to the LIN pin (pin 12) as depicted in circuit of
Fig. 18 which has been given obviously. When the
internal logic detects logic high at pin 12, the Lo pin (pin
1) will be driven.
Moreover, the converter circuits have some protection
features. The zener diodes at the analog inputs are used
for over voltage protection. They ensure that the
feedback voltage does not exceed their breakdown
voltage of 5 V. The small ceramic capacitors are putted
in parallel with the large electrolytics that have a
relatively high resistance to reduce the SER and hence
improve the efficiency and performance of the circuit.
X. DIGITAL IMPLEMENTATION OF PID CONTROLLER
The program boost control code is written use Arduino
software and loaded into the microcontroller directly.
ATmega328P executes calculation based on the PID
control algorithm and generate a PWM control signal
using Timer 2 and working in fast PWM Mode. Figure
21 shows the flowchart of the proposed digital PID
algorithm.
Fig. 21: Flowchart of the digital PID algorithm
XI. EXPERIMENTAL RESULTS AND ANALYSIS
The boost converter system is tested with a closed loop
only using digital PID controller under the same states
introduced in closed loop simulation subsection in order
to establish the circuit operation and emphasize the
simulation results.
i- Variable input voltage and constant load
The input voltage is supplied from rectified variable
AC source. It increased and decreased is steps (increased
from 180V to 240V then return to 180V). The load is
constant and has power of 1kW. The output voltage
response is appeared in Fig. 22 where it is close to 325V
during two changes in the input voltage. The practical
results offer that the output voltage is approximately
match the simulation result and thereby confirms the
controller design. The positive and negative overshoots
are about 45V and 60V respectively. The positive
overshoot is due by the rise in the input voltage while
negative overshoot due to the drop in the input voltage.
The settling time is approximately 1s and is higher than
simulated time (0.1 ms) due to the parasitic impact of the
practical boost components circuit.
(a)
(b)
Fig. 22: Output voltage response at during step change
input voltage
a) when Vin step up from 180 to 240V,
b) when Vin step down from 240 to 180
ii- Constant input voltage and variable load
International Journal of Science Engineering and Advance
Technology, IJSEAT, Vol. 4, Issue 7
ISSN 2321-6905
July -2016
www.ijseat.com Page 331
The experimental circuit is tested under load step
changes from 400W to 1200W then to 400W for 200 V
input. Figure 23 gives the response of the output voltage
during step changes in the load. The output voltage is
settled at 325V under load variation after time interval
depends on the changing in the load. The results give
that the overshoot is approximately 25V and the voltage
is settled after 0.5s. The positive overshoot is due to the
drop in the load and negative overshoot due to the rise in
the load.
Fig. 23: Output voltage during load variation
XII. CONCLUSION
This paper presented the design, simulation, and
implementation of the DC-DC boost converter with PID
controller. First, the system has been simulated in
MATLAB software and gives efficient results when the
sudden changes in the input voltage as well as in the load
are made. After that, a practical design has been
constructed and tested for the same simulation
conditions. The digital PID controller was executed
using Arduino microcontroller that has several on board
advantages. Experimental results exhibit a good
regulation performance for the output voltage under all
test conditions. Thus the designed DC-DC Boost
converter can be used in PV system applications or other
fluctuations sources.
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