Students:Thomas Carley Luke KetchamBrendan ZimmerGreg Landgren
Advisors:Dr. Woonki NaDr. Brian HugginsDr. Yufeng Lu
Bradley UniversityDepartment Of Electrical Engineering
11/30/11
Presentation OutlineSummary and Overall System Block DiagramDC SubsystemMaximum Power Point TrackingBoost Converter TestingAC SubsystemScheduleComponent List
Project SummarySupplies DC and AC PowerPhotovoltaic ArrayBoost Converter to step up PV voltageMaximum Power Point Tracking DC-AC converter for 120VrmsLC filter
System Block Diagram
Photovoltaic Boost
ConverterInverter
DSPBoard
LC Filter
DC OutputAC Output
Grid
DC Subsystem Boost ConverterMaximum Power Point Tracking (MPPT) System
S
T
C11u
L14.299m D1
C20.001
V
Vin
V
Vo
VA
10k100u
VPmax
20800
Simulation Results
0 10 20 30 40 50 60Time (s)
0
-20
20
40
60
80
100
Vin Vo
Boost Converter Full Bridge
S
T
V
251000
DC Subsystem RequirementsThe 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 VoltsThe 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 ComponentsMOSFET
Vds = 250V Id = 110A Pdiss = 694WHeatsink
Inductor1mH 25A500uH 35A
Gate DriverMOSFET or
IGBT2.5A 500V
Solar Panel x 450W12V
DC Subsystem ComponentsCurrent Sensor
30A63-69 mV/A
Sensing Op ampUsed with voltage
dividerDSP Board
TMS320F2812
MPPT“Perturb and Observe” methodChange Boost Converter duty cycle based on
change in PV powerChanging duty cycle changes the current
drawn from the PVAnytime the system is not at the
maximum power point, it is notat it’s most efficient point
MPPT Flowchart Calculate Power
Calculate change in power over change in duty cycle
(slope)
Compare current duty cycle with previous duty cycle
Compare current power with last power
Increase Duty
Is the slope positive or negative?
Decrease Duty
Negative Positive
Boost Without MPPT
25
VVcell_1
1000u
D1330uA
Icell_1
Without MPPT
VS_1
V Po_1
V Pmax_1
S
T
V
3000uC6
50R6V Vgate_1
V
1000u
Boost With MPPT
25
VVcell
1000u
D330u
A
Icell
Maximum Power Point Tracking UsingPerturb and Observe Method
MPPT - Perturb and Observe method
VS
V Po
V Pmax
v
Gatingi
S
T
V
Cout3000u
50Rload
V Vgate
V
1000u
MPPT Circuit
dU1
PI
dv/dtdP>0
dU2
dP<0
Uref
dP>0 dP<0
i
v
Gating
Output Power Without MPPT
0 0.1 0.2 0.3 0.4 0.5Time (s)
0
-20
20
40
60
80
Pload_1 Pmax_1 Po_1
Output Power With MPPT
0 0.1 0.2 0.3 0.4 0.5
Time (s)
0
20
40
60
80
Pload Pmax Po
PV Models in SimulinkMade 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 Feb March April May June July Aug Sep Oct Nov Dec
kWh/(m^2 day) 3.271 4.109 4.642 4.921 5.239 5.740 5.880 5.727 5.639 4.562 2.957 2.721
W/m^2 136.292 171.208 193.417 205.042 218.292 239.167 245.000 238.625 234.958 190.083 123.208 113.375
PV cell characteristics
Vpv
PV
To Workspace
Scope1
Scope
Product
PV power
1e-9*(exp(u/26e-3)-1)
PN-junction characteristic
1/1000
Insolation to ISC current gain
1000
Insolation
I-V characteristic
ISC
Id
Ipv
Ipv
Ppv
Ppv
Vpv
Vpv
I
V V
P
PV Module Characteristics
Vpv
Vpv
Insolation
Ipv
Ppv
PV module (V)
PV1
PV power
Insolation
I-V characteristic
Vpv
Vpv
Ipv
I
V
P
V
Insolation = 200, 400, 600, 800, 1000 W/m2
4-module PV Array
XY power
XY V-I
ProductIpv
Insolation
Vpv
Ppv
PV module (I)
PV4
Ipv
Insolation
Vpv
Ppv
PV module (I)
PV3
Ipv
Insolation
Vpv
Ppv
PV module (I)
PV2
Ipv
Insolation
Vpv
Ppv
PV module (I)
PV1
Ipv Ramp
1000
Insolation
Add Ipv
Ipv
Vpv
Vpv
Ppv
Ppv
V
V
P
I
Boost Converter Lab TestingBuilt boost converter from components Dr.
Na provided.
5V220u
330u MBR3045PT
470u
VVin
VVo
IRFZ34NL
A
1k0.1u 470u 470u 50
Boost Converter Lab Testing0 to 3.3V signal from DSP board controlling the
MOSFETAt a switching frequency of 10kHz with a 50% duty cycle
the 5V input voltage was boosted to about 10V.Increasing duty cycle, increased VoutDecreasing duty cycle, decreased Vout
After testing this setup we will be able to build our Boost converter circuit quickly.
DSP Board ProgrammingSpectrum Digital eZdsp F2812Texas Instruments Code ComposerMatlab/Simulink
Simulink A/D Interfacing
Simulink PWM Generation
Manual PWM Duty Ratio Control
PWM GenerationExperimental Results
80% Duty Ratio 30% Duty Ratio
AC SubsystemInverterOutput filter
AC Subsystem - InverterInverter topologyInverter operationSimulations
AC SubsystemInverter Topology
Inverter single phase H-bridge
AC SubsystemInverter Operation - BipolarA reference sinusoidal waveform is compared
to a triangular carrier waveformWhen the reference voltage is equal to the
carrier voltage a transition in the switching signal occurs
AC SubsystemInverter Operation - Bipolar
V
Carrier Waveform
Vcarr
10 1m
V
V Vcontrol
Simulation schematic
AC SubsystemInverter Operation - Bipolar
Reference (blue) and carrier (red) waveforms
Switching signal
AC SubsystemInverter Operation - Bipolar
Inverter output. Switches from +Vd to -Vd
AC SubsystemInverter Operation - BipolarSwitching signal is inverted and fed to other
pair of switchesSwitch pairs are switched simultaneouslyOnly one reference signal needed, but
performance is poor
AC SubsystemInverter Operation - UnipolarTwo reference sinusoids are compared to a
triangular waveformSwitch pairs not switched simultaneously
AC SubsystemInverter Operation - Unipolar
450
V
Va1
Carrier Waveform
10 1m
V Vcarr
A
V Vcont1 V Vcont2
VVa2
Simulation schematic
AC SubsystemInverter Operation - Unipolar
Image source: Tian
References and carrier waves
Switching signal 1
Switching signal 2
Output
Inverter Operation - Comparison
Bipolar harmonic output
Unipolar harmonic output
AC Subsystem - Output FilterInverter output includes switching harmonicsFilter smoothes output
AC Subsystem RequirementsThe 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 ComponentsInverter switchesGate drivesPower supplies
Commercial Grid Tie Inverters
Company SMA Solar Technology Xantrex
Product Sunny Boy 700-US GT2.8
AC Power 460W, 120Vac 2700 W, 208Vac / 2800W, 240Vac
AC Voltage Output
106 - 132 Vac 183 - 229 Vac / 211 - 264 Vac
Output Frequency 59.3 - 60.5 Hz 59.3 - 60.5 Hz
Harmonics > 3% > 3%
Max. efficiency 92.4% 94.6%
Power Factor Unity > 0.95 %
ScheduleBrendan Tom Luke
Week 1 Build Boost Build Inverter Build BoostWeek 2 Voltage Sensing DSP Programming Current SensingWeek 3 MPPT Code DSP Programming MPPT CodeWeek 4 Interfacing DSP Programming InterfacingWeek 5 Interfacing Interfacing InterfacingWeek 6 Circuit + Software Interfacing Circuit + SoftwareWeek 7 Testing Testing TestingWeek 8 DC-AC Integration DC-AC Integration DC-AC IntegrationWeek 9 DC-AC Integration DC-AC Integration DC-AC IntegrationWeek 10 Build Fullbridge+Boost LC Filter Build Fullbridge+BoostWeek 11 Circuit + Software Testing Circuit + SoftwareWeek 12 DC-AC Integration DC-AC Integration DC-AC IntegrationWeek 13 DC-AC Integration DC-AC Integration DC-AC IntegrationWeek14 Presentation Prep Presentation Prep Presentation PrepWeek 15 Presentation Prep Presentation Prep Presentation Prep
Component ListPart Type Part # Website Digikey or Newark # DESC QTY Unit Price PriceMOSFET IXTH110N25T www.digikey.com IXTH110N25T-ND Vds = 250V Id = 110A Pdiss = 694W 10 6.165 $61.65Capacitor B43456 www.digikey.com 495-4232-ND 1500uF 450V 8 38.09 $304.72Current Sensor ACS712ELCTR-30A-T www.digikey.com 620-1191-1-ND 30A 63 to 69 mV/A 3 4.52 $13.56Ultrafast Diode HFA50PA60C N/A If(av) = 25A Vf = 1.3C Vr = 600V 3 12.23 $36.69IGBT IRG4PC30UD N/A Vce = 600v Ic = 23A Pdiss = 100W 10 2.5 $25.00Solar Panel BP 350 J N/A 50W 12V 3 279 $837.00Inductor 7448262510 www.newark.com 08P2917 1mH 25A 4 22.91 $91.64
Inductor 7448263505 www.newark.com 08P2918 500uH 35A 2 22.91 $45.82Heat sink WA-T247-101E www.digikey.com WA-T247-101E-ND Clip-on TO-247 6 1.8 $10.80Gate Driver IR2110 www.digikey.com IR2110PBF-ND MOSFET IGBT Driver 2.5A 500V 25 2.8036 $70.09Op Amp OP484FPZ www.digikey.com OP484FPZ-ND Sensing Op Amp 10 11.14 $111.40PWM Buffer 74LVC4245A www.digikey.com 568-5002-1-ND IC Translator 10 0.912 $9.12PWM Buffer 74HCT541 www.digikey.com 568-4592-1-ND IC Buffer 10 0.502 $5.02
$1,622.51
1
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-inverter-schematic.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): 1508-516.
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?