1. Performance Analysis of Single Phase
Photovoltaic Inverter Topologies and
Implementation of Piccolo Series Controller
TMS320C28027 based
Pulse Width Modulated Signal for Single Phase
Bidirectional High Frequency Link Inverter
Prashant V. Thakre, Associate Prof.
SSBT College of Engg. & Technology, Jalgaon, Maharashtra
Dr. Saroj Rangnekar, Prof. & Head,
Energy Dept., MANIT, Bhopal
1
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2. INDEX
•
•
•
•
•
•
•
•
•
•
•
•
•
Introduction
Problem Formulation
Methodology Adopted
Literature Review
Overview of Thermal & Solar Photovoltaic System
Solar Tracking System
Types of Solar Photovoltaic System
Inverter Topologies
Modeling of Closed Loop System
Simulink Models
Experimental Setup
Conclusion
References
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3. Introduction
With the growing energy demand, increasing
global environmental issues, and depleting
energy resources such as coal, oil and gas, the
need to develop and utilize new sources of
energy seems inevitable. Therefore renewable
energy resources such as solar, wind, biomass,
hydro and geothermal etc appear as important
alternative energy options. Solar energy is one of
the few clean and abundant renewable energy
resource which is being use extensively in recent
years.
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4. Energy demand projection in India
[www.mnre.gov.in]
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5. Introduction
• Worldwide lot of work on solar technology is
going on even in the countries where there is
limited sunshine over the year. India is blessed
with a bright sunshine round the year. With the
advancement in control techniques, solar
energy is becoming one of the alternate
renewable energy sources for generation of
power.
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6. Introduction
• Today, with the explosive growth and
expanding efficiency of digital technology,
digital inverter system is having edge over
analog
systems.
Microprocessors,
Microcontrollers and Digital Signal Processors
(DSP) have been used for Pulse Width
Modulation (PWM) pulse generation and realtime controller of inverter systems
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7. Aims and Objectives
• Study and implementation of maximum peak power tracking
system
• Study of various control techniques for PWM inverters
• MATLAB/Simulink model of closed loop boost converter
• Selecting appropriate control technique for the BHFL solar
photovoltaic inverter
• Analytical modeling of the BHFL solar photovoltaic inverter
and controller design
• System Testing
• Hardware implementation
• Test and results
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8. Problem formulation
• Identifying the solar tracking methods for maximum power output.
• Mathematical modeling of selected tracking system for maximum power
point tracking
• Development of MATLAB/Simulink models for solar photovoltaic system.
• Design and developing inverter models & PWM generations using
MATLAB/Simulink
• Testing the developed models with different test conditions.
• Selecting the suitable model based on amount of total harmonic
distortion, voltage and current waveforms and switching frequencies, for
implementing hardware circuit for inverter.
• Designing and development of hardware circuit for selected solar
photovoltaic inverter model.
• Development of algorithm for generating PWM signals in real time.
• Interfacing of digital controller to PC for uploading the software for
generating the PWM signals.
• Testing the digital controller based solar photovoltaic system in real time
mode.
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9. Methodology Adopted
• Development of mathematical models for solar photo
voltaic system.
• Development of inverter models & PWM generations
using MATLAB/Simulink.
• Testing of models with different switching frequencies.
• Development of algorithm for generating PWM signals
in case of real time analysis.
• Interfacing of DSP kit to PC for uploading the software
project for generating the PWM signals.
• Development of hardware model for BHFL solar
photovoltaic inverter with appropriate driver circuit.
• Interfacing BHFL inverter to solar panel.
• Implementation of maximum peak power tracking
system
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10. Solar Tracking System (P&O Method)
The voltage corresponding to the maximum power given to the panel is dependent
on solar irradiation and on temperature
Where Iph is the current generated from photon as a function
of temperature and solar irradiation,
Isat is the saturated reverse current,
q is the charge on electron,
A is the ideality factor,
K is the Boltzmann’s Constant,
T is the temperature,
rs is the series resistance
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11. Solar Tracking System
The light generated current and the saturated reverse current is
expressed as
Where Tr is the reference temperature
Eg is the energy band gap
Iscr is the short circuit current at reference temperature
KI is the current temperature coefficient
S is per unit irradiation
Irr is the reverse current at reference temperature
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12. Solar Tracking System
Maximum peak power is found by solving the
following equation
The optimal voltage Vm is used to consider the
voltage perturbation given by equation
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13. Types of Solar Photovoltaic Systems
Solar photovoltaic system is classified as :
a) Grid-connected solar PV systems
b) Stand Alone System
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14. Transformer isolated high-frequency
link inverter
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15. Modeling of closed loop BHFL Inverter
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16. Equivalent circuit of the BHFL
inverter
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17. Modeling of closed loop BHFL Inverter
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18. Modeling of closed loop BHFL Inverter
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19. Modeling of closed loop BHFL Inverter
Also equation are expressed as
the values of rl & rc are assumed to be very small & are neglected .Thus
equation becomes
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20. Modeling of closed loop BHFL Inverter
Based on the equations a dynamic model of the system is
represented by block diagram as shown
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21. Modeling of closed loop BHFL Inverter
Since the controller is to be implemented using a digital
processor ,the continuous time space equations are
converted into discrete form .The discrete time state space
equations with sampling period of Ts are represented as
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22. Modeling of closed loop BHFL Inverter
Where
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23. Modeling of closed loop BHFL Inverter
The discrete time equation are rewritten as:
From equations, it is observed that additional disturbance
terms appear due to discretisation of modal. As compared
with continuous time modal shown , there exist two
disturbances instead of one, acting on inductor current and
output voltage.
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24. Modeling of closed loop BHFL Inverter
The current & voltage disturbances are represented by
the equation,
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25. Modeling of closed loop BHFL Inverter
Based on the above equations the digital model are
represented by a block diagram as shown where Z-1
is unit delay.
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26. Modeling of Solar Photovoltaic Cell
(MATLAB/Simulink model of PV cell)
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27. Simulink Model of Solar Photovoltaic
System
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28. MATLAB/Simulink model of closed
loop boost converter
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29. Solar PV Inverter model with pulse
generator using MATLAB/Simulink
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30. Solar PV Inverter model with PWM
generation
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31. Solar PV Inverter model with bipolar
scheme
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32. Solar PV Inverter model with unipolar
switching scheme
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33. Solar PV Inverter model with 1800
mode
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34. Model of single phase BHFL solar PV
inverter
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35. Model of solar photovoltaic system
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36. Stand alone solar photovoltaic system
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37. Results and discussion
The simulation and experimental results for a
photovoltaic system was carried out. The
performance of different types of inverter systems
were studied with respect to the photovoltaic input
using simulink models. A prototype photovoltaic
system for 500VA was also developed and its result
were studied and verified. For studying and verifying
the prototype hardware model, an advanced digital
controller TMS320C28027 of Texas Instruments was
considered.
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38. Results and discussion
Initially the performance of solar cell was
studied by using a simulink model. After that
the characteristics of solar panel, considering
arrays of panel was also tested with the help of
MATLAB/simulink model by considering
parameters such as insolations, short circuit
current and short circuit voltage. The
characteristics of solar panel were obtained
with the help of algorithm and programming.
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39. Output power with different values of
insolations
Sr. No.
Insolation (w/m2)
Iout
Vout
Output Power(watts)
1)
925
3.914
3.914
15.32
2)
950
9.769
9.769
95.43
3)
975
10.57
10.57
111.8
4)
1000
10.93
10.93
119.4
5)
1025
11.15
11.15
124.4
6)
1050
11.32
11.32
128.2
7)
1075
11.45
11.45
131.2
8)
1100
11.56
11.56
133.2
9)
1125
11.65
11.65
135.8
10)
1150
11.74
11.74
137.7
11)
1175
11.81
11.81
139.4
12)
1200
11.87
11.87
140.9
13)
1340
12.16
12.16
147.9
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40. Output power based on rated values
of standard panels
Sr. No.
Model No.
Isc
(Amp)
Voc
(volts)
Imax
(Amp)
Vmax
(volts)
Pmax
(Watts)
Ipv
(Amp)
Vpv
(volts)
Output
Power(W)
1)
BP3230T
8.4
36.7
7.9
29.1
230
18.85
18.85
355.5
2)
BP3225T
8.3
36.6
7.7
29.1
225
18.85
18.85
355.5
3)
BP3170T
5.2
43.6
4.8
35.6
170
23.18
23.18
537.5
4)
BP3215T
8.1
36.5
7.4
29.1
215
18.85
18.85
355.5
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41. Output characteristics of boost converter
(X axis – Time, Y axis – DC Voltage, Duty ratio, Efficiency)
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42. Output of Solar Photovoltaic Inverter
System
(X axis – Time, Y axis - AC voltage, AC current, input current,
duty ratio, input and output power)
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43. Parameters for single phase bidirectional high
frequency link inverter
Sr. No.
1)
Parameters
DC input voltage
Values
Vdc = 230 volts
2)
Inductance
L1 = 0.166 mH
3)
Capacitance
C1 = 1 µf
4)
Inductance
L2 = .5 H
5)
Carrier frequency (Stage 1)
Fs = 15 KHz
6)
Modulation Index (Stage 1)
0.8
7)
Carrier frequency (Stage 2)
Fs = 1KHz
8)
Modulation Index (Stage 2)
0.8
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44. Voltage waveform at output of transformer
( X axis – Time, Y axis – Voltage)
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45. Output voltage waveform of BHFL inverter
( X axis – Time, Y axis – Voltage)
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46. THD for single phase full bridge bidirectional
high frequency link inverter
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47. Output signal with fs = 1.5 KHz
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48. Output signal with fs = 2.5 KHz
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49. Output signal with fs = 10 KHz
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50. Parameters considered for standalone
PV system
S.No.
Components
Value
1)
Vdc
DC voltage
12 volts
2)
C1
Capacitor
110µf
3)
L1
Inductor
2.5mH
4)
R1
Resistor
0.01ohms
5)
C2
Capacitor
4700µf
6)
L2
Inductor
5mH
7)
R2
Resistor
3 ohms
8)
C3
Capacitor
1 µf
9)
R3
Resistor
.01 ohms
10)
C3
Capacitor
1 µf
11)
C4
Capacitor
3 µf
12)
C5
Capacitor
3 µf
13)
R4
Resistor
1 ohm
14)
fs
Switching frequency
1.5KHz
15)
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MI
Modulation Index
0.8
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51. Output current and voltage of standalone
PV system
(X axis – Time, Y axis – Current and Voltage)
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52. Battery Voltage for standalone system
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53. THD for standalone PV system
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54. % THD Values
S. No.
Inverter Topology
1)
Single Phase PV Inverter with pulse
generator
64.25
16.70%
2)
Single Phase PV Inverter with bipolar
switching
90.99
5.84%
3)
Single Phase PV Inverter with unipolar
switching
219
5.65%
4)
Single Phase BHFL PV Inverter with
unipolar switching
179.9
4.95%
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Fundamental
Component
(50Hz)
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55. Hardware specification of the circuit
PV Module Specification
Model No.
SLP5 - 12
Battery Specification
Microtek
Inverter Circuit Specification
IGBT driver (TLP250)
IGBT (G4PC60U)
Filter Circuit Specification
Inductor
Resistor
Capacitor
Digital Controller
TMS320C28027 (Texas Instruments)
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Rated Power = 5 watt
Rated Voltage = 17.5 volts
Rated Current = 0.3 Amp
Voc = 21.6 volts
Isc = 0.34 Amp
Insolation = 1000 watt/m2
DC voltage rating = 12 volts
Rated Current = 7.2 Ah
Vcc = 10 – 35 volts
Max. threshold Current (If) = 5 mA
Max. output current (Iout) = 1.5 Amp
Vmax = 600 volts, Imax = 23 Amp
Operating Temp. = -55 deg. To +150 deg.
10 mH
22 ohms
22 µf
32 bit CPU, 60 MHz device
On chip flash, SARAM
OTP memory, 3.3 volt supply
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56. Experimental setup for generating PWM
signal
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57. PWM signal generated from
TMS320C28027
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58. Hardware implementation of BHFL
inverter
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59. Connecting BHFL inverter to
TMS320C28027
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60. Observed AC Signal
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61. Experimental setup of single phase
prototype model of BHFL inverter
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62. Conclusion
•Based on the output generated by the closed
loop boost converter, a MATLAB/Simulink
model of BHFL photovoltaic inverter was
developed and its output was studied by
considering different switching frequencies. It
was observed that by increasing the switching
frequencies there is an improvement in output
signal. The amount of THD for single phase
BHFL photovoltaic inverter was found to be
4.95%
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63. Conclusion
Hardware Implementation
After simulating, testing and observing the output signals
of various simulink models a hardware prototype model of
photovoltaic bidirectional high frequency link inverter
was developed for 500 VA rating. The pwm signals for
IGBT’s were generated by using piccolo series dsp
processor TMS320C28027. The generated pwm signals
from GPIO pins of processor were observed on
oscilloscope first and then with proper driver circuit
consisting of TLP250, given to IGBT’s. The generated ac
output signal was also observed on DSO and then applied
to the load.
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70. Thank You
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