1. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.3, Issue.2, March-April. 2013 pp-1212-1219 ISSN: 2249-6645
www.ijmer.com 1212 | Page
Mohammed Shoaib, 1
Prof V. Nagaraj2
1
Department Of Electrical &Electronics engineering,
2
Assoc.Prof. (Senior Scale), Manipal Institute of Technology, Manipal University, Manipal, India
Abstract: In many remote or underdeveloped areas, direct access to an electric grid is impossible and a photovoltaic
inverter system would make life much simpler and more convenient. With this in mind, this paper aims to design, and
simulate PV inverter in proteus professional software. This inverter system could be used as backup power during outages,
battery charging, or for typical household applications for rural especially. The principle is to adapt the output voltage of
the solar module to the battery by using the technique of pulse width modulation (PWM). The sinusoidal pulse width
modulated (PWM) waveform is generated from inverter in laboratory by 16 bit microprocessor through program developed
using a novel technique of direct modulation strategy .The key features of the system are a true 50Hz, 230Vsinusoidal
voltage output, a wide input range, and a power output of up to 350 watts. The overall goal is to design this system while
minimizing component costs.. In addition, inverters in the lower price range typically lack most of the features. solar home
lighting systems mostly comprises of solar panel, solar charger, battery & a inverter, The main motivation of this paper or
the uniqueness of this project is to combine both the solar charger as well as inverter together to ATMEGA 32 RISC based
which works up to 16MIBS which reduces the cost as well as the system becomes compact.
Keywords: Pv, Pwm, Mcu, Proteus, Dpwm, Pwm Charger.
I. Introduction
India s off-grid solar (PV) market has three major segments: captive power plants (where the majority of generation
is consumed at the source), telecom towers, and rural electrification. The market potential for these PV segments has created
an off grid solar market in India. India like other developing countries has made tremendous progress in producing energy in
agriculture sectors. However, it lags behind in meeting the entire energy demand in remote rural and its nearby suburban or
urban areas. As a result, our country is facing acute shortage of power especially in those village areas where utility grids are
either not available or its further extension is not possible due to costly affair. Even in the sub-urban or urban area of these
villages where utility grids are available, only 20% electricity is available for end users and so they lack such basics of
human need as lighting, irrigation, communication, primary health care facility, safe drinking water, education etc.
Renewable energy is the only feasible option to electrify these villages and its surrounding areas.
Along with increases of demand for the new energy, and the key technologies of use new energy sources is how to
integrate new energy into electrical energy. In this paper high computing speed, low-power single chip MCU ATMEGA 32
is used as the control chip, improve the inverter efficiency. This article also describes the structure of the inverter, control
methods, focuses on software design and finally summarized.
The primary function of a charge controller in a stand-alone PV system is to maintain the battery at highest possible
state of charge while protecting it from overcharge by the array and from over discharge by the loads [1]. Although some PV
systems can be effectively designed without the use of charge control, any system that has unpredictable loads, user
intervention, optimized or undersized battery storage (to minimize initial cost) typically requires a battery charge controller.
The algorithm or control strategy of a battery charge controller determines the effectiveness of battery charging and PV array
utilization, and ultimately the ability of the system to meet the load demands. Additional features such as temperature
compensation, alarms, meters, remote voltage sense loads and special algorithms can enhance the ability of a charge
controller to maintain the health and extend the lifetime of a battery, as well as providing an indication of operational status
to the system caretaker.
Important functions of battery charge controllers and system controls are to [2]:
 Prevent Battery Overcharge: to limit the energy supplied to the battery by the PV array when the battery becomes fully
charged.
 Prevent Battery Over discharge: to disconnect the battery from electrical loads when the battery reaches low state of
charge.
 Provide Load Control Functions: to automatically connect and disconnect an electrical load at a specified time, for
example operating a lighting load from sunset to sunrise.
 A series charge controller or series regulator disables further current flow into batteries when they are full. A shunt
charge controller or shunt regulator diverts excess electricity to an auxiliary or "shunt" load, such as an electric water
heater, when batteries are full.
Proteus Based Simulation of PV Inverter for Rural Electrical
Service

2. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.3, Issue.2, March-April. 2013 pp-1212-1219 ISSN: 2249-6645
www.ijmer.com 1213 | Page
Simple charge controllers stop charging a battery when they exceed a set high voltage level, and re-enable charging
when battery voltage drops back below that level. Pulse width modulation (PWM) [2] and maximum power point tracker
(MPPT) technologies are more electronically sophisticated, adjusting charging rates depending on the battery's level, to
allow charging closer to its maximum capacity. Charge controllers may also monitor battery temperature to prevent
overheating. Some charge controller systems also display data; transmit data to remote displays, and data logging to track
electric flow over time [4].
II. System Block Diagram
2.1Inverter Drive circuit and Filter circuit design.
Figure: 1
ATMega32 microcontroller: It acts as the heart of the system. It controls and monitors entire system. The main
function of this microcontroller is to generate SPWM signals. These signals are given to Half-bridge switches to convert dc
voltage to ac voltage. Microcontroller also takes care of the protection. It protects the load from over voltage, under
voltage.This system includes a feedback network where at the output AC is converted to DC using bridge rectifier and is
properly isolated using an npn based opto coupler and a voltage divider circuit which is fed back to adc module of MCU and
output voltage is regulated by controlling the duty cycle of the DPWM.
In the present work sinusoidal pulse width modulation (SPWM) technique is used to control the switches of the
Halfe-bridge. This technique is widely used in inverter to digitize the power so that a sequence of voltage pulses can be
generated by the on and off of the power switches. The pulse width modulation inverter has been the main choice in power
electronics, because of its circuit simplicity and rugged control scheme.
After analysis and comparison, the part of the contra variance use half-bridge inverter circuit, Inverter Bridge is
composed of FET IRF3205, using 2n3906 and 2 Bc547 as a driver circuit. Single-chip generated PWM signal, go though
2n3906 to control the inverter switching devices IRF3205 the shutdown of conduction, then inverter can produce sine wave
outputs. But the sine wave contains many high-order harmonic generation, required the LC filter circuit to be smooth, non-
standard high-order harmonic generation of sine wave. The size of capacitance and inductance values required theoretical
calculations and the actual debugging to determine. In this design, we take C = 100uF, L = 40uH.
2.2 Pwm Control
A software program has been developed to generate sinusoidal pulses for N numbers in a half cycle using direct
modulation strategy (DPWM) whose widths are proportional to amplitude of sine wave at sampled points (Fig.2).
Mathematically the pulse width and corresponding notch width are expressed by (1) and (2) respectively as:
Pulse width (Pi)
= K Pwm x 2 Sin (2i - 1) π / (2*N) . (1)
Where,
i = 1, 2, 3,…..N
K = Voltage Factor (0 –1)
P wm = ( D – G ) * 2
D = 180 / (2*N)
G = Minimum Gap between pulses (say 1degree) at K=1
N = Number of PWM pulses in Half sine wave (180 degree i.e. = 10 ms)
Notch width (Ti) = 2D - [1/2(Pi – 1 + Pi)]. (2)

3. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.3, Issue.2, March-April. 2013 pp-1212-1219 ISSN: 2249-6645
www.ijmer.com 1214 | Page
Figure 2: Programmable DPWM sinusoidal
Modulated (N = 3 ) half sine wave of 50 Hz . Y
axis = Amplitude (5V), X axis = Total time (T) in
half cycle i.e 180 degree =10ms.
III. System Software Design
3.1proteus Introduction
Proteus supports multiple mainstream microcontroller system simulation, such as 51 series, AVR series, PIC12
PIC16 series, PIC18 series, Z80 series, HC11 series, series, 68,000 series, etc. And provide software debugging function and
its periphery connection device of RAM, ROM, keyboard, motor, LED, LCD, AD/DA, partial SPI device.
With the development of science and technology, the computer simulation technology has become an important
sector of many design method of early. It is designed to be flexible, results, the process of unity. It can make the design time
is shortened, cost reduction, also can reduce the risk of engineering. Believe in microcontroller application of PROTEUS can
also have extensive application.
3.2Target specifications
3.2.1 Inverter specifications.
Frequency 50 Hz +/- 2Hz
Efficiency >80 %
Output 350 watts, 12VDC ~ 220 V +/- 5
Harmonics <5 %
spwm Sine wave inverter
Mobility Portable, microcontroller based
Protection circuits yes
Table1
3.2.2 Solar charge controller specification:
 Prevents battery from being overcharged and damaged by the solar panel
 Compatible with 12 volt battery bank
 Overload, short circuit, and reverse polarity protected.
 LED's indicate charging status.
3.3 Simulation Results
3.3.1 pv inverter simulation
Figure 3: (Schematic of Proposed PV Inverter with battery charger.)

4. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.3, Issue.2, March-April. 2013 pp-1212-1219 ISSN: 2249-6645
www.ijmer.com 1215 | Page
Fig4. (Schematic of inverter)
Fig5. (Pulse train drawing the mosfet T=20 ms, TON=10ms &TOFF=10ms)
Fig6. (Output voltage waveform as per simulated resultsVO=228 Volts ).
Fig7. (Current wave form as per simulated results IO=1.7 Amps).
A B C D E F G H J K
B C D E F G H J KA
FILE NAME:
BY:
DATE:
PAGE:
schematic for inverter.DSN
3/26/2013
<NONE>
E:mtech projectmtechschematic for inverter.DSNPATH:
1 of 1
REV:<NONE> TIME: 11:01:50 PM
DESIGN TITLE: E:mtech projectmtechschematic for inverter.DSN
0
1
2
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
3
9
R1
12k
R2
12k
Q1
BC547
Q2
2N3906
R4
100
R5
10k
M1
IRF3205S
M2
IRF3205S
R6
100
R7
10k
R8
12k
R9
12k
Q4
BC547
R10
1k5
R3
1k5
Q3
2N3906
TR?
TRAN-2P3S
D?
1N4007
D1
1N4007
+88.8
ACVolts
R3(1)
L1
1.2mh
CL1
10u
M1(G)
M2(G)
TR?(P1)
L1(2)
BR1
2W06G
RA
12k
RB
254
6
5
4
1
2
U1
OPTOCOUPLER-NPN
RC
1k
100%
RD
1k
+5
RC(2)
L?
230V
RA(1)
CD
100uf
+12
v_out
pulse2
pulse 1
+12
feed back to MCUPB0/T0/XCK
1
PB1/T1
2
PB2/AIN0/INT2
3
PB3/AIN1/OC0
4
PB4/SS
5
PB5/MOSI
6
PB6/MISO
7
PB7/SCK
8
RESET
9
XTAL2
12
XTAL1
13
PD0/RXD
14
PD1/TXD
15
PD2/INT0
16
PD3/INT1
17
PD4/OC1B
18
PD5/OC1A
19
PD6/ICP1
20
PD7/OC2
21
PC0/SCL
22
PC1/SDA
23
PC2/TCK
24
PC3/TMS
25
PC4/TDO
26
PC5/TDI
27
PC6/TOSC1
28
PC7/TOSC2
29
PA7/ADC7
33
PA6/ADC6
34
PA5/ADC5
35
PA4/ADC4
36
PA3/ADC3
37
PA2/ADC2
38
PA1/ADC1
39
PA0/ADC0
40
AREF
32
AVCC
30
U?
ATMEGA32
D7
14
D6
13
D5
12
D4
11
D3
10
D2
9
D1
8
D0
7
E
6
RW
5
RS
4
VSS
1
VDD
2
VEE
3
LCD?
LM016L
RLCD
1K
VCC
VCC
A
B
C
D

5. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.3, Issue.2, March-April. 2013 pp-1212-1219 ISSN: 2249-6645
www.ijmer.com 1216 | Page
3.4 simulation of PWM charge controller
Figure 8(schematic of pwm based charge controller)
Solar Charge controller is a device, which controls the battery charging from solar cell and also controls the battery
drain by load. The simple Solar Charge controller checks the battery whether it requires charging and if yes it checks the
availability of solar power and starts charging the battery. Whenever controller found that the battery has reached the full
charging voltage lavels, it then stops the charging from solar cell. On the other hand, when it found no solar power available
then it assumes that it is night time and switch on the load. It keeps on the load until the battery reached to its minimum
voltage levels to prevent the battery dip-discharge. Simultaneously Charge controller also gives the indications like battery
dip-discharge, load on, charging on etc
OPERATION OF SYSTEM: Pulse Width Modulation (PWM) is the most effective means to achieve constant voltage
battery charging by switching the solar system controller‟s power devices. When in PWM regulation, the current from the
solar array tapers according to the battery‟s condition and recharging needs. In the fig 8 solar charge is controlled by
controlling the duty cycle ,such that an optimum 13.75 volts is fed to battery for charging purpose.2N3055 NPN power
transistor , Packaged in a TO-3 case style, it is a 15 amp, 60 volt is used as switching device Initially 50 %duty cycle is fed in
MCU using PORT C0. As the solar voltage is unregulated the voltage is controlled by adjusting the duty cycle .Two
reference voltage is fed in MCU, whenever solar voltage is < reference voltage V1 (>> Pwm), similarly vice versa.
3.4 Simulation Results for PV Charger
The proposed charge controller is simulated by using Proreus ISIS 7 Professional for five cases listed in table 1 and
the simulation results shown in figures 8-12.
Test no Solar
voltage
Battery
voltage
Duty
cycle%
1 18 11.0 96%
2 16 11.0 99%
3 10 12.0 35%
4 17 13.5 0%
Table 2
3.4.1Algorithm for Charge Controller
As microcontroller software works as sequential basis, it will perform these steps Sequentially.
1. Power On, RESET
2. Define Input / Output of the ports
3. Setup ADC for measurement
4. Start ADC Module
5. Measure ADC2, ADC3, ADC4, ADC5. ADC2 for „Solar Voltage‟, ADC3 for „Battery High Set‟, ADC4 for „Battery Low
Set‟ and ADC5 for „Battery Voltage‟
6. If „Battery Voltage‟ < „Battery High Set‟ and „Solar Voltage‟ > „Battery Voltage‟ then
A B C D E F G H J K
A B C D E F G H J K
9
8
7
6
5
4
3
2
1
0
9
8
7
6
5
4
3
2
1
0
FILE NAME:
BY:
DATE:
PAGE:
schematic.pdf1.DSN
3/22/2013
<NONE>
E:mtechprojectmtechcharger3schematic.pdf1.DSNPATH:
1 of 1
REV:<NONE> TIME: 10:37:46 AM
DESIGN TITLE: E:mtech projectmtechcharger3schematic.pdf1.DSN
Q6
2N3055
Q5
2N2222
D4
1N4007
D5
1N4007
DC CAP
1000u
11%
DUTYPOT
10k
PB0/T0/XCK
1
PB1/T1
2
PB2/AIN0/INT2
3
PB3/AIN1/OC0
4
PB4/SS
5
PB5/MOSI
6
PB6/MISO
7
PB7/SCK
8
RESET
9
XTAL2
12
XTAL1
13
PD0/RXD
14
PD1/TXD
15
PD2/INT0
16
PD3/INT1
17
PD4/OC1B
18
PD5/OC1A
19
PD6/ICP1
20
PD7/OC2
21
PC0/SCL
22
PC1/SDA
23
PC2/TCK
24
PC3/TMS
25
PC4/TDO
26
PC5/TDI
27
PC6/TOSC1
28
PC7/TOSC2
29
PA7/ADC7
33
PA6/ADC6
34
PA5/ADC5
35
PA4/ADC4
36
PA3/ADC3
37
PA2/ADC2
38
PA1/ADC1
39
PA0/ADC0
40
AREF
32
AVCC
30
ATMEGA32
ATMEGA32
DCCAP(1)
D4(K)
Q4
2N2222
GND
R8
1k
R9
1k
DUTY POT(2)
DUTY POT(3)
GND
R3
220
D3
LED-GREEN
Q1
2N2222 Q2
2N2222
R5
1k
R4
220
D0
LED-RED
R61k
Q3
2N2222
+5V
R2
1k
D2
LED-YELLOW
+5V
RLYS/B
12V
+12
Q7
2N2222
RLYS/B
1K
LS?
BUZZER
D7
14
D6
13
D5
12
D4
11
D3
10
D2
9
D1
8
D0
7
E
6
RW
5
RS
4
VSS
1
VDD
2
VEE
3
LCD
LM016L
RLCD1
1k
VCC
R7
4.7K
15%
SOLARPOT
10K
C4
0.1uf
R10
4.7K
14%
BATTERYPOT
10K
C5
0.1uf
SOLAR POT(3)
+5V
D1
1N4003
C1
47uf
C2
0.1uf
VI
1
VO
3
GND
2
7805
7805
C3
0.1uf
R1
10k
GND
GND
GND
GND
FUSE
30A
GND
+12
C3(1)
GND
1
2
SOLARTERMINAL
+
1
2
BATTERYTERMINAL
1
CENTERTAPPED

6. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.3, Issue.2, March-April. 2013 pp-1212-1219 ISSN: 2249-6645
www.ijmer.com 1217 | Page
a. Switch ON Battery Charging
b. Switch ON Charging LED
c. Switch OFF Battery High LED
7. If „Battery Voltage‟ > or = „Battery High Set‟ then
a. Switch OFF Battery Charging
b. Switch OFF Charging LED
c. Switch ON Battery High LED
8. If „Solar Voltage‟ < „Battery Voltage‟ then
a. Switch OFF Battery Charging
b. Switch OFF Charging LED
c. Switch ON Load
9. If „Battery Voltage‟ < or = „Battery Low Set‟ then
a. Switch OFF Load
b. Switch ON Battery Low LED
10. If „Battery Voltage‟ > „Battery Low Set‟ then
a. Switch OFF battery Low LED
11. Go to Step 5.
Figure: 9. (the above schematic refers to step no 6 of the algorithm).
Figure: 10. Simulation Result for Test number 1(channel c represents the output of the MCU PWM signal)
Figure: 11. Simulation Result for Test number 2(channel c represents the output of the MCU PWM signal).

7. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.3, Issue.2, March-April. 2013 pp-1212-1219 ISSN: 2249-6645
www.ijmer.com 1218 | Page
Figure: 12. Simulation Result for Test number 3(channel crepresents the output of the MCU PWM signal)
Figure: 13. Simulation Result for Test number 4(channel crepresents the output of the MCU PWM signal)
Figure13. (The above schematic refers to step no9 of the algorithm)
Figure14. (The above graph shows switching on; of the relay once battery reaches its low set point).

8. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.3, Issue.2, March-April. 2013 pp-1212-1219 ISSN: 2249-6645
www.ijmer.com 1219 | Page
IV. Conclusion
The article is being simulated in the Proteus software, the hardware must be tested accordingly, Proteus not only
make many MCU visualize, but also can visualize many MCU examples. Which is 80–90 % similar to real operating device?
The above system does not require carrier signal or a comparator circuit as usually require in conventional triangular PWM
generator circuit and thus reduces the cost as well as complexity in producing PWM base drive signals.
V. Acknowledgment
The authors pay their sincere gratitude to the Mr I.B rao the MD of power one Microsystems & the Management of Power
one Microsystems ,Bangalore for funding this technical work.. The author also extends their heartily thanks to R&D
Engineer Mr M. M. Venkateswaran & Mr Valache Siddalingappa, for their valuable time and effort for scrutinizing the
design of the project.
References
[1] G.J. Vander et al, “150W Inverter – an optimal design for use in solar home system”, International Symposium on Industrial
Electronics, Proceedings ofISIE, 1998, Vol. 1, pp 57-62.
[2] B. Lindgrin, “A 110 W inverter for photovoltaic application”, Published in International Journal of Renewable Energy Engineering,
April 2002.
[3] S. Martínez, M. Castro, R. Antoranz, and F. Aldana, “Off-line uninterruptible power supply with zero transfer time using integrated
magnetics,” IEEE Trans. Ind. Electron, vol. 36, no. 3, pp. 441–445, Aug. 1989.
[4] M. T. Tsai and C. H. Liu, “Design and implementation of a cost-effective quasi line-interactive UPS with novel topology,” IEEE
Trans. Power Electron., vol. 18, no. 4, pp. 1002–1011, Jul 2003
[5] Adel Nasiri, Zhong Nie, Stoyan B. Bekiarov, and Ali Emadi, “ An On-Line UPS System With Power Factor Correction and Electric
Isolation Using BIFRED Converter” IEEE transaction on Industrial Electronics, vol, 55.no.2,pp. 722 - 730 ,February 2008.
[6] Ross, J., Markvart, T., and He, W.: „Modelling Battery charger Regulation for a Stand-alone Photovoltaic System‟ , Sol. Energy,
2000, 69, (3), pp. 181–190
ABOUT THE AUTHORS
MD SHOAIB has obtained his B.Tech degree in EEE from New Horizon College of engineering and currently
pursuing his MTECH in power electronics system and control in Manipal University .His area of interest is power
converters and embedded systems.
V.NAGARAJ has has obtained his ME in power systems from Mysore university, and He has 34years of teaching
experience. He has published 2 research papers at national level. His area of teaching is Applications of soft
computing systems to power Systems