SOLAR array MONITOR(s.a.M.)

GROUP 14WILL ADROBEL

MOHAMMED JEBARISTEPHEN R. PARKER

MIKE TELLADIRA

Sponsored by QuickBeam Energy

Motivation

Growing demand for all solar power devices Increasingly larger arraysGovernment tax credit

Closer monitoring neededTroubleshooting is laboriousLots of money lost due to bad panels.

Government programs require documentation

Specifications

Monitoring capacity 5 strings of solar panels Cost <$5 per solar panel Frequency of reporting <15 minutes

Physical size 5"x 7“x2”

Transmission wireless or direct wire

Lifetime 15 to 20 years.

S.A.M. Block Diagram Picture below

shows S.A.M. installed inside the combiner box.

CURRENT SENSOR

Mohammed Jebari

Current sensor spec.

Operates on 5Vdc Low power consumption Resist to temperature

changes Handle a voltage up to

500V

Short response time Easy to install Very cheap

ComparisonCSLT6B100 CSA-1V Asahi EQ-710L

Supply voltage

4.5V ~ 10.5V 4.5V ~ 5.5V 3V ~ 5.5V

Supply current

9mA 11-16mA 9-12mA

temperature -25 to +100 °C -40 to +125°C -30 to +100°C

Response time

3µs 6µs 3-5µs

price $6.55 $4.95 $3.27

CSA-1V sentron Basic electrical connection diagram

Pins 4, 6 & 7 are used for factory programming.

Pins 4 & 7 should be terminated to VDD (Pin 2)

Pin 6 should be terminated to GND (Pin 5)

Single ended output config.

differential output config.

S.A.M. uses differential output configuration

Current Measurement CSA-1V differential

output voltage for a circular conductor (wire) located on top of the IC can be approximated with the equation:

d = distance (mm) from chip surface to center of wire

I = Current in conductor

)3.0(

*060.0

mmd

Ivoutdiff

Interface circuits

Differential to single ended, 0-5V swing for DC current.

Gain of 20

Output level be no more than 2.5 +/- 2.0 volts to prevent electrical saturation and non-linearity

vv outdiffout*2

Accuracy considerations

The absolute accuracy of the current measurement depends on several factors which are:

Distance between the conductor and sensor The closest the conductor to the sensor, the highest

the accuracy will be

Stray fields The sensor is an open filed magnetic sensor therefore

it can sense fields from other sources

Acc. considerations (CONT.) The conductor position should be the same for each part in a production run.

The conductor should form right angle will minimize any pickup from adjacent conductors.

The higher the current and closeness of the conductor to the IC, the more accurate the reading will be.

Acc. considerations (CONT.)

Sensitivity variation The variation in magnetic sensitivity of the

CSA-1V is +/- 3%.

DC Offset voltageSpecified to +/-15mV max

TemperatureTemperature changes affect magnetic

sensitivity and DC offset voltage

Temp. affects on offset volt.

DC offset voltage changes as temperature varies

Offset drift change is between -0.2 and 0.2 (mV/°C)

Add temp. sensor Off. drift = K*∆T

Temperature sensor

Analog temperature sensor 3V to 5.5V, 90µA Measure temp. −40° to +230°F±1.0°F accuracy (at +77°F) < ±2.0°F Output of 10mV per degree F Price $ 2.51

LM34 DS18B20

1-Wire digital thermometer 3V to 5.5V, 90µA Measure temp. -67°F to +257°F ±33°F Accuracy 14°F to +185°C Can Be Powered from Data Line Price $4.25

LM34 Temp. sensor

LM34 is an analog temperature sensor, its voltage output can be affected by noise.

Add 0.1 µF capacitor between the power and the ground pin. Reduce the effects of noise picked up on

the Signal line. Improve the stability of the measurement.

AFFECT OF TEMPERATURE The affect of

temperature on the output voltage is very low.

The changes in the output voltage is less than 40mV for all the sensors.

60 80 100 120 140 160 180 2000

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

f(x) = 0.000370797310278579 x + 0.278040345821326f(x) = 0.000431316042267051 x + 0.270259365994236f(x) = 0.000371757925072046 x + 0.253631123919308

f(x) = 0.000463016330451489 x + 0.334755043227666

f(x) = 0.000311239193083574 x + 0.621412103746398

Sensor1Linear (Sensor1)Linear (Sensor1)Sensor2Linear (Sensor2)Sensor3Linear (Sensor3)Sensor4Linear (Sensor4)Sensor5Linear (Sensor5)

Temperature in degree F

Outp

ut

Volt

age in (

V)

CSA-1V CALIBRATION All sensors have

almost the same slope 0.299 to 0.319

At 0.05Amp, each sensor has different output voltage.

Adding 20kΩ potentiometer at the differential output of each sensor will help in adjusting the first value of the output voltage.

0 1 2 3 4 5 60

0.5

1

1.5

2

2.5

3

f(x) = 0.299770727653111 x + 0.228530220961225

f(x) = 0.319138943789158 x + 0.37115392628694f(x) = 0.307760868942195 x + 0.336502020462557f(x) = 0.299583184443453 x + 0.471081985142598

f(x) = 0.30547465713467 x + 0.718055186105691

Sensor1Linear (Sensor1)Linear (Sensor1)Linear (Sensor1)Sensor2Linear (Sensor2)Linear (Sensor2)Linear (Sensor2)Sensor3Linear (Sensor3)Linear (Sensor3)Sensor4Linear (Sensor4)Linear (Sensor4)Linear (Sensor4)Sensor5Linear (Sensor5)Linear (Sensor5)Linear (Sensor5)

Current in (A)

Outp

ut

Volt

age in

(V)

CSA-1V CALIBRATION (CONT.)

After tuning the potentiometers, the current sensors now have the same voltage output at 0.05Amp.

0 1 2 3 4 5 60

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

f(x) = 0.292216260890685 x + 0.0329714519877478f(x) = 0.30542551513847 x + 0.0356591677438888

f(x) = 0.289067473038756 x + 0.0350635397877634f(x) = 0.294574843091738 x + 0.0337838534949704f(x) = 0.280334164445591 x + 0.0313047029490157

Sensor1Linear (Sensor1)Sensor2Linear (Sensor2)Sensor3Linear (Sensor3)Sensor4Linear (Sensor4)Sensor5Linear (Sensor5)

Current in (A)

Outp

ut

Volt

age in (

V)

Voltage divider Low current

drain

Low power consumption

less than 0.155 mW

Voltage divider ratio 100:1

Stephen R. Parker

MICROCONTROLLER

micro. requirement

Bits of precision in the AD measurements:12 bits yields 212 – 1 = 4095 increments

Max 600 volts / 4095 = .147 volts of discrimination 10 bits yields 210 –1 = 1023600 / 1023 = .59 volts of discrimination

Number of A/D pins:6 input lines x 2 measurements = 12

Desirability of integrating stages into one chip: Nice but $$ Price: Powerful microcontrollers for less than $10

Micro. requirement (cont.)

Power requirements: drawing from UNLIMITED power source

Operating temperature: Must endure 40°C to 85°C

Connectivity: USART

Software programmable: C language compiler available

Case: DIP (dual inline packaging) for using on a breadboard

Criteria

PIC18F4458-I/P

Silicon Laboratorie

s C8051F542-

IM

Analog Devices ADUC7026BSTZ6

2

Microchip Technology

PIC24HJ128GP204-E/PT

Temp -40°C ~ 85°C

-40°C ~ 125°C -40°C ~ 125°C -40°C ~ 125°C

#AD inputs

12 18 12 12

#prec. bits

12 12 12 12

Connect. USART USART USART USART

Compiler available

“C compiler optimized architectur

e

C compilers “available”

No mention of C compiler

compatibility

“C compiler optimized

instruction set”

Case 40 pin DIP surface mount

40 pinsurface mount

40 pin surface mount

Dev. kit $60(200) $99 $86 $130

Micro. alternatives

Processor PIC18 F 4458

Memory 8 bit , 2K x 8 RAM Program memory FLASH Speed 48 MHz Connectivity USART module, USB A/D channels 13 pins A/D bits 12 Power 4.5 - 5.5 volts Power dissipation absolute maximum 1 W Packaging 40 pin DIP Operating temp. -40°C to 85°C

Micro. circuit connections

Software Flow Chart

TRANSMISSION William Adrovel

Transmission

SENSOR DATA BANDWIDTH 1 A/D Sample from sensor = 12 bits

XXXXXXXX XXXX

1 Sample will require 2 Bytes for storageXXXXXXXX XXXX0000

We will sample 11 Channels every 2 seconds at 2 Bytes each

11 bytes of data/second … very little amount of data

Transmission (cont.) METHODS OF TRANSMISSION

WiredDB9 Serial to Ethernet

Simplest and lowest cost Winter Haven will have this solution

WirelessXBEE

Transmission (cont.) Types of QuickBeam Projects

Commecial Office Building

Winter Haven: DB9 Connection Ethernet

Distributed Solar Arrays Wireless

Residential Wired : DB9 or Ethernet Connection

WINTER HAVEN S.A.M.

UART for Serial Transmission

Serial to Ethernet protocol converter - WIZ110SR WIZ110SR connects to onsite router or

switch and will push data to QuickBeam’s FTP Server every two seconds

WIZ110SR can be set up for Dynamic or Static IP

Winter Haven will have Static IP address

Mike Telladira

POWER SUPPLY

DISTRIBUTED 5VDC POWER SYSTEM

5 Hall effect sensors: 5Vdc at 9mA each = 54mAMicroprocessor: 5Vdc at 90mA = 90mAEthernet Adaptor WIZ110SR = 180mA

_____________________________

Total = 315mA

CHOOSING THE BUCK REGULATOR

LM 22675-5.0 4.5V to 42V Up to 1 Amp

Webench support Few components, smaller footprint Gerber file -Yes Evaluation PCB -Yes

5VDC BUCK REGULATOR CIRCUIT

Inductor

LM22675-5 chip

Diode

WHY USE THE EVALUATION PCB

Inductor

LM22675-5 Cinx Diode

Hybrid Power System

3.3Vdc Buck Key Criteria: 90% efficient Has an Enable pin

STEP DOWN METHODS Transformer

Voltage Divider In Series

1.5watts / (85% eff) /16V = 110.3mA

Transformer issues:1. Interlacing2. Interweaving

1. To insure that when QuickBeam’s panels are producing at least 180Vdc the S.A.M is powered2. But needs to have a low power loss.

Imax = 191mA

SOLAR PANEL SELECTION CRITERIA Atleast 12V 10 to 20 watts NOT for a trickle charger

1/100 C.C. Work in low light Thin Film vs. Polycrystalline

PROJECT BUDGET

BUDGETDescription Cost R&D Reproduction

Cost

Power Regulator $51.48 $51.48 $51.48

Solar Panel $74.54 $74.54 $74.54

Assembly Box $18.20 $18.20 $18.20

Current Sensors $39.70 $39.70 $39.70

Processor $05.00 $05.00 $05.00

Resistors $10.50 $10.50 $10.50

Potentiometers $22.50 $22.50 $22.50

Op-amps $27.92 $27.92 $27.92

DB9 to Ethernet $30.00 $30.00 $30.00

Miscellaneous and Test Equi

- - - - $650 - - - -

Total $279.84 $981.32 $279.84

QUESTIONS