Students:
Thomas Carley
Luke Ketcham
Brendan Zimmer
Greg Landgren
Advisors:
Dr. Woonki Na
Dr. Brian Huggins
Dr. Yufeng Lu
Bradley University
Department Of Electrical Engineering
11/30/11
Presentation Outline
 Summary and Overall System Block Diagram
 DC Subsystem
 Maximum Power Point Tracking
 Boost Converter Testing
 AC Subsystem
 Schedule
 Component List
Project Summary
 Supplies DC and AC Power
 Photovoltaic Array
 Boost Converter to step up PV voltage
 Maximum Power Point Tracking
 DC-AC converter for 120Vrms
 LC filter
System Block Diagram
AC Output
DC Output
Photovoltaic
Boost
Converter
DSP
Board
Inverter
LC Filter
Grid
DC Subsystem
 Boost Converter
 Maximum Power Point Tracking (MPPT) System
V
S
Pmax
Vin
Vo
L1
4.299m
V
100u
800
T
20
C1
1u
V
A
10k
D1
V
C2
0.001
Simulation Results
Vin
Vo
100
80
60
40
20
0
-20
0
10
20
30
Time (s)
40
50
60
Boost Converter Full Bridge
V
S
1000
T
25
DC Subsystem Requirements
 The boost converter shall accept a voltage from the
photovoltaic cells.
 The input voltage shall be 48 Volts.
 The average output shall be 200 Volts +/- 25 Volts.

The voltage ripple shall be less than 3 Volts
 The boost converter shall perform maximum
power point tracking.
 The PWM of the boost converter shall be regulated
based on current and voltage from the PV array.
 The efficiency of the MPPT system shall be above 85%.
DC Subsystem Key Components
 MOSFET
 Vds = 250V
 Id = 110A
 Pdiss = 694W
 Heatsink
 Inductor
 1mH 25A
 500uH 35A
 Gate Driver
 MOSFET or IGBT
 2.5A 500V
 Solar Panel x 4
 50W
 12V
DC Subsystem Components
 Current Sensor
 30A
 63-69 mV/A
 Sensing Op amp
 Used with voltage divider
 DSP Board
 TMS320F2812
MPPT
 “Perturb and Observe” method
 Change Boost Converter duty cycle based on change in
PV power
 Changing duty cycle changes the current drawn from
the PV
 Anytime the system is not at the
maximum power point, it is not
at it’s most efficient point
MPPT Flowchart
Calculate Power
Compare current power
with last power
Compare current duty cycle
with previous duty cycle
Calculate change in power
over change in duty cycle
(slope)
Negative
Increase Duty
Is the slope
positive or
negative?
Positive
Decrease Duty
Boost Without MPPT
V Pmax_1
S_1V
Icell_1 V
S
Vcell_1
330u
A
1000u
T
D1
V
C6
3000u
V
Vgate_1
R6
50
1000u
25
V
Without MPPT
V Po_1
Boost With MPPT
Maximum Power Point Tracking Using
Perturb and Observe Method
V Pmax
S
V
V
Icell
S
Vcell
330u
A
D
Cout
3000u
1000u
T
V
V
Vgate
Rload
50
1000u
25
V
i
Gating
v
MPPT - Perturb and Observe method
V Po
MPPT Circuit
dP>0
dv/dt
v
i
dP<0
PI
Gating
Uref
dP>0
dU1
dP<0
dU2
Output Power Without MPPT
Pload_1
Pmax_1
Po_1
80
60
40
20
0
-20
0
0.1
0.2
0.3
Time (s)
0.4
0.5
Output Power With MPPT
Pload
Pmax
Po
80
60
40
20
0
0
0.1
0.2
0.3
Time (s)
0.4
0.5
PV Models in Simulink
 Made models of PVs using resources from the
University of Colorado at Boulder
 Insolation – a measure of solar energy on an area over a
given amount of time.
 Usually in units of W/m^2
Solar Insolation Peoria, IL
Jan
kWh/(m^2 day)
W/m^2
Feb
March
April
May
June
July
Aug
Sep
Oct
Nov
Dec
3.271
4.109
4.642
4.921
5.239
5.740
5.880
5.727
5.639
4.562
2.957
2.721
136.292
171.208
193.417
205.042
218.292
239.167
245.000
238.625
234.958
190.083
123.208
113.375
PV cell characteristics
PV power
Scope
Vpv
Ppv
Ipv
Ppv
Product
To Workspace
I-V characteristic
1e-9*(exp(u/26e-3)-1)
Vpv
Vpv
PN-junction characteristic
Id
Scope1
1000
1/1000
Insolation
ISC
Ipv
Insolation to
ISC current gain
I
P
V
PV
V
PV Module Characteristics
Vpv
Vpv
Vpv
PV power
Ipv
Vpv
PV module (V)
Insolation
I-V characteristic
Ipv
Ppv
PV1
Insolation
Insolation = 200, 400, 600, 800, 1000 W/m2
P
I
V
V
4-module PV Array
Ipv
1000
PV module (I)
Insolation
Vpv
I
Ppv
PV1
Insolation
Ipv
PV module (I)
Insolation
Vpv
Ppv
Vpv
PV2
Ipv
PV module (I)
Insolation
V
Vpv
XY V-I
Vpv
Ppv
PV3
Ppv
Ppv
Ipv
PV module (I)
Insolation
Product
Vpv
XY power
Ppv
PV4
Add
Ipv
P
Ipv Ramp
Ipv
V
Boost Converter Lab Testing
 Built boost converter from components Dr. Na
provided.
Vin
Vo
V
330u
A
5V
220u
0.1u
1k
V
MBR3045PT
IRFZ34NL
470u
470u
470u
50
Boost Converter Lab Testing
 0 to 3.3V signal from DSP board controlling the MOSFET
 At a switching frequency of 10kHz with a 50% duty cycle
the 5V input voltage was boosted to about 10V.
 Increasing duty cycle, increased Vout
 Decreasing duty cycle, decreased Vout
 After testing this setup we will be able to build our Boost
converter circuit quickly.
DSP Board Programming
 Spectrum Digital eZdsp F2812
 Texas Instruments Code Composer
 Matlab/Simulink
Simulink A/D Interfacing
Simulink PWM Generation
Manual PWM Duty Ratio Control
PWM Generation
Experimental Results
80% Duty Ratio
30% Duty Ratio
AC Subsystem
 Inverter
 Output filter
AC Subsystem - Inverter
 Inverter topology
 Inverter operation
 Simulations
AC Subsystem
Inverter Topology
Inverter single phase H-bridge
AC Subsystem
Inverter Operation - Bipolar
 A reference sinusoidal waveform is compared to a
triangular carrier waveform
 When the reference voltage is equal to the carrier
voltage a transition in the switching signal occurs
AC Subsystem
Inverter Operation - Bipolar
10
1m
Simulation
schematic
Vcarr
V
V
V
Vcontrol
Carrier Waveform
AC Subsystem
Inverter Operation - Bipolar
Reference (blue) and
carrier (red) waveforms
Switching signal
AC Subsystem
Inverter Operation - Bipolar
Inverter output. Switches from +Vd to -Vd
AC Subsystem
Inverter Operation - Bipolar
 Switching signal is inverted and fed to other pair of
switches
 Switch pairs are switched simultaneously
 Only one reference signal needed, but performance is
poor
AC Subsystem
Inverter Operation - Unipolar
 Two reference sinusoids are compared to a triangular
waveform
 Switch pairs not switched simultaneously
AC Subsystem
Inverter Operation - Unipolar
A
10
1m
450
Simulation
schematic
Va1
V
V
Vcarr
V
Va2
V
Carrier Waveform
Vcont1
V
Vcont2
AC Subsystem
Inverter Operation - Unipolar
References and
carrier waves
Switching signal 1
Switching signal 2
Output
Image source: Tian
Inverter Operation - Comparison
Bipolar harmonic
output
Unipolar harmonic
output
AC Subsystem - Output Filter
 Inverter output includes switching harmonics
 Filter smoothes output
AC Subsystem Requirements
 The AC side of the system shall invert the output of the
boost converter.
 The output of the inverter shall be 120 Volts RMS.
 The output shall be 60Hz +/- 0.1Hz.
 The inverter output shall be filtered by a LC filter.
 The filter shall remove high switching frequency
harmonics.
 Total harmonic distortion of the output shall be less
than 15%.
AC Subsystem Key Components
 Inverter switches
 Gate drives
 Power supplies
Commercial Grid Tie Inverters
Company SMA Solar Technology
Product Sunny Boy 700-US
AC Power 460W, 120Vac
AC Voltage 106 - 132 Vac
Output
Output Frequency 59.3 - 60.5 Hz
Harmonics > 3%
Max. efficiency 92.4%
Power Factor Unity
Xantrex
GT2.8
2700 W, 208Vac / 2800W, 240Vac
183 - 229 Vac / 211 - 264 Vac
59.3 - 60.5 Hz
> 3%
94.6%
> 0.95 %
Schedule
Week 1
Week 2
Week 3
Week 4
Week 5
Week 6
Week 7
Week 8
Week 9
Week 10
Week 11
Week 12
Week 13
Week14
Week 15
Brendan
Build Boost
Voltage Sensing
MPPT Code
Interfacing
Interfacing
Circuit + Software
Testing
DC-AC Integration
DC-AC Integration
Build Fullbridge+Boost
Circuit + Software
DC-AC Integration
DC-AC Integration
Presentation Prep
Presentation Prep
Tom
Build Inverter
DSP Programming
DSP Programming
DSP Programming
Interfacing
Interfacing
Testing
DC-AC Integration
DC-AC Integration
LC Filter
Testing
DC-AC Integration
DC-AC Integration
Presentation Prep
Presentation Prep
Luke
Build Boost
Current Sensing
MPPT Code
Interfacing
Interfacing
Circuit + Software
Testing
DC-AC Integration
DC-AC Integration
Build Fullbridge+Boost
Circuit + Software
DC-AC Integration
DC-AC Integration
Presentation Prep
Presentation Prep
Component List
1
Digikey or Newark # DESC
Part Type
Part #
Website
MOSFET
Capacitor
Current Sensor
Ultrafast Diode
IGBT
Solar Panel
Inductor
IXTH110N25T
B43456
ACS712ELCTR-30A-T
HFA50PA60C
IRG4PC30UD
BP 350 J
7448262510
www.digikey.com IXTH110N25T-ND
www.digikey.com 495-4232-ND
www.digikey.com 620-1191-1-ND
N/A
N/A
N/A
www.newark.com 08P2917
Vds = 250V Id = 110A Pdiss = 694W
1500uF 450V
30A 63 to 69 mV/A
If(av) = 25A Vf = 1.3C Vr = 600V
Vce = 600v Ic = 23A Pdiss = 100W
50W 12V
1mH 25A
10
8
3
3
10
3
4
6.165
38.09
4.52
12.23
2.5
279
22.91
$61.65
$304.72
$13.56
$36.69
$25.00
$837.00
$91.64
Inductor
Heat sink
Gate Driver
Op Amp
PWM Buffer
PWM Buffer
7448263505
WA-T247-101E
IR2110
OP484FPZ
74LVC4245A
74HCT541
www.newark.com
www.digikey.com
www.digikey.com
www.digikey.com
www.digikey.com
www.digikey.com
500uH 35A
Clip-on TO-247
MOSFET IGBT Driver 2.5A 500V
Sensing Op Amp
IC Translator
IC Buffer
2
6
25
10
10
10
22.91
1.8
2.8036
11.14
0.912
0.502
$45.82
$10.80
$70.09
$111.40
$9.12
$5.02
$1,622.51
08P2918
WA-T247-101E-ND
IR2110PBF-ND
OP484FPZ-ND
568-5002-1-ND
568-4592-1-ND
QTY Unit Price Price
References
 “PV Module Simulink Models.” ECEN2060. University of Colorado Boulder.
 Rozenblat, Lazar. "A Grid Tie Inverter for Solar Systems." Grid Tie Inverter Schematic and
Principles of Operation. 6 Oct. 2011. <http://solar.smps.us/grid-tie-inverterschematic.html>.
 Tafticht, T., K. Agbossou, M. Doumbia, and A. Cheriti. "An Improved Maximum Power
Point Tracking Method for Photovoltaic Systems." Renewable Energy 33.7 (2008): 1508516.
 Tian, Yi. ANALYSIS, SIMULATION AND DSP BASED IMPLEMENTATION OF
ASYMMETRIC THREE-LEVEL SINGLE-PHASE INVERTER IN SOLAR POWER SYSTEM.
Thesis. Florida State University, 2007.
 Zhou, Lining. EVALUATION AND DSP BASED IMPLEMENTATION OF PWM
APPROACHES FOR SINGLE-PHASE DC-AC CONVERTERS. Thesis. Florida State
University, 2005.
Questions?