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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