Students:Thomas Carley Luke KetchamBrendan Zimmer

Advisors:Dr. Woonki NaDr. Brian Huggins

Bradley UniversityDepartment Of Electrical Engineering

2/28/12

Presentation Outline

Brief Summary of Project GoalsFunctional Description, System Block

Diagram, and Performance Specifications Implementation, Construction, and TestingSchedule and Milestones

Project Summary

Supplies DC and AC PowerPhotovoltaic ArrayBoost Converter to step up PV voltageMaximum Power Point Tracking DC-AC converter for 120Vrms 60HzLC filter

System Block Diagram

Photovoltaic Boost Converter Inverter

DSPBoard

LC Filter

DC Output AC Output

Grid

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 20 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%.

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%.

Boost Converter

10

1000u

0 240.50000

100u 636

VA

Test Boost Converter

10V to 30V

Boost Converter

0 0.02 0.04 0.06 0.08 0.1Time (s)

0

10

20

30

40

50

60

V1

Output Voltage (V)

Boost Converter

0 0.02 0.04 0.06 0.08 0.1Time (s)

0

-2

2

4

6

8

10

I1

Output Current (A)

Boost Converter

48

4000u

50000 0 274.

100u 200

VA

5

V

48V – 200V

Soft Start

Boost Converter

0 0.05 0.1 0.15 0.2 0.25Time (s)

0

100

200

300

400

V1

0 0.05 0.1 0.15 0.2 0.25Time (s)

0

50

100

150

200

250

300

V1

Without Soft Start (V) With Soft Start (V)

Boost Converter

0 0.05 0.1 0.15 0.2 0.25Time (s)

0

-10

10

20

30

40

I1

0 0.05 0.1 0.15 0.2 0.25Time (s)

0

-5

5

10

15

I1

Without Soft Start (A) With Soft Start (A)

Boost Converter

Output Voltage Inductor Current

Boost Converter Future Work

RC snubber circuit to reduce voltage spikes Adjustment of load resistor value Adjustment of output capacitor Implementation of soft start either through

– Switched Resistor– Slowly increasing duty cycle with DSP

Power Supplies

120Vrms 60Hz input from wall 15V, 5V, and 3.3V output Consists of Transformer, Diode Rectifier,

470uF capacitor, and voltage regulators Needed for Gate Drivers, Op Amps, Sensing

ICs, and other logic devices

110

169.760

C470u

LM7815AC15V Regulator

LM78L05AC5V Regulator

LM1117T-3.33.3V Regulator

Diode Rectifier

Power Supply

Power Supply

Implementing MPPT with DSP

Voltage Divider Current Sensor Simulink Modeling for TMS320F2812

Voltage Divider

OP484

+5V

+3.3V0 to 12V

20.5k

7.5k

50k

0.01uF

100

1000pF

VADC

+3.3V

Current Sensing

Current Sensor thru current

Current Sensor Vout

0.001 A 2.513 V

0.1 2.517

0.2 2.521

0.3 2.525

0.4 2.529

0.5 2.532

0.6 2.536

VAV

A V AveI Ave /0869565.26

30038.01.0

..

Current Sensing Circuit

1

2

3

4

8

7

6

5

ACS712Vout

+5V

I+

I- 0.001uF

0.01uF

Simulink Model

2Ipv

1Vpv

3/4096

convert to Volts1

3/4096

convert to Volts

26.08696

Volts to AmpsSubtract

C281x

PWM

W1

PWM

MPPT_V

MPPT_I

F2812 eZdsp

60

Duty Cycle

double

Data Type Conversion1

double

Data Type Conversion

ADC input from Voltage divider

ADC input from Current sensor

C281x

ADC

A0

A1

ADC

2.513

2.513V

Single Phase Inverter

Inverter H-Bridge and gate drives Tested with complementary PWM signals

To do: Add isolation Add logic compatibility circuitry

Inverter Experimental Results

Vsource = 10 V Rload = 496 Ω

Sinusoidal PWM

The magnitude of a triangle carrier signal is compared to a sinusoidal reference

If Vreference > VcarrierPWM signal = high

If Vreference < VcarrierPWM signal = low

Sinusoidal PWM – Simulink

SPWM – Simulink Results

LC Filter

Second order LC filter transfer function:G(s) = 1/(L*C*s^2+1)

LC Filter - Simulation

Simulation Results

Unfiltered frequency spectrum

Filtered frequency spectrum

Schedule and Milestones

Luke Brendan Tom3/1 Simulink MPPT Snubber for Boost Inverter DSP

3/6, 3/8 Inverter DSP3/13, 3/153/20, 3/22 Inverter DSP3/27, 3/29

4/3, 4/54/9

4/10, 4/124/17, 4/19

4/244/26, 5/1

5/7

Extra time

MPPT with smaller Boost Converter

Boost Converter and Inverter IntegrationMPPT and Boost with 2 PV's

Boost Converter and Inverter Integration

Spring Break

Final Project Oral PresentationsFinal Project Report Due

Draft of Final Project Report

Organize Information for Oral PresentationOral Presentation Prep

Questions?

PV data collection

• Mostly sunny, with a high near 36. West southwest wind between 8 and 11 mph, with gusts as high as 15 mph.

BP350J collection Feb 9, 2012

0

2

4

6

8

10

12

14

16

18

20

8:31:12 8:38:24 8:45:36 8:52:48 9:00:00 9:07:12 9:14:24 9:21:36 9:28:48 9:36:00 9:43:12

Time of Day

Load

Vol

tage

[V] a

nd C

urre

nt[A

]

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

Load

Pow

er[k

W]

Load_VLoad_ALoad_W

Boost Converter

Current Before Diode Drain Voltage