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?