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Motivation

SOLAR array MONITOR ( s.a.M ) Group 14 Will Adrobel Mohammed Jebari stephen R. parker mike telladira Sponsored by QuickBeam Energy. Growing demand for all solar power devices Increasingly larger arrays Government tax credit Closer monitoring needed

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Motivation

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  1. SOLAR array MONITOR(s.a.M)Group 14Will AdrobelMohammed Jebaristephen R. parkermike telladiraSponsored by QuickBeam Energy

  2. Growing demand for all solar power devices • Increasingly larger arrays • Government tax credit • Closer monitoring needed • Troubleshooting is laborious • Lots of money lost due to bad panels. • Government programs require documentation Motivation

  3. Monitoring capacity 6 strings of solar panels • Cost $5 per solar panel. • Frequency of reporting <15 minutes Specifications

  4. Physical size 5"x 2"x10“ • Transmission wireless or direct wire • Power source the solar array. • Lifetime 15 to 20 years. SPECIFICATIONS (CONT.)

  5. S.A.M, Block Diagram

  6. Current sensor Mohammed Jebari

  7. Low power consumption • Resist to temperature variation • Handle a voltage up to 500V • Short response time • Easy to install • Very cheap Current sensor spec.

  8. Comparison

  9. CSA-1V sentronBasic 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)

  10. Single ended output config.

  11. differential output config. • Needs differential output configuration for S.A.M

  12. 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

  13. Interface circuits • Differential to single ended, 0-5V swing for DC current. • Output level be no more than 2.5 +/- 2.0 volts to prevent electrical saturation and non-linearity

  14. 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 Accuracy considerations

  15. 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.

  16. Sensitivity variation • The variation in magnetic sensitivity of the CSA-1V is +/- 3%. • DC Offset voltage • Specified to +/-15mV max • Temperature • Temperature changes affect magnetic sensitivity and DC offset voltage Acc. considerations (CONT.)

  17. 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

  18. Temperature sensor LM34DS18B20 • 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 • 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

  19. 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. LM34 Temp. sensor

  20. Voltage divider • Low current drain • Low power consumption less than 0.155 mW • Voltage divider ratio 100:1

  21. Voltage divider (cont.)

  22. Stephen R. Parker microcontroller

  23. 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 = 1023 600 / 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

  24. 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

  25. Micro. alternatives

  26. 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 Processor PIC18 F 4458

  27. Micro. circuit connections

  28. Software Flow Chart

  29. ADCON0 • Bit 0 enables the ADC • Bit 1 status bit • Bits 2-5 selects the AD channel • Bits 6,7 unused, read as zero • ADCON1 • Bits 0-3 configures whether the ports are AD or DA • Bit 4 selects AN3 as Vref+* • Bit 5 selects AN2 as Vref- • Bits 6,7 unused, read as zero • ADCON2 • Bits 0-2 selects what to use as the “conversion” clock • Bit 3-5 selects data acquisition time • Bit 6 unused, read as zero • Bits 7 selects right or left justification • ADRESH and ADRESL • When the A/D conversion is complete the result is stored there, the status bit of the ADCON0 register is cleared and the A/D Interrupt Flag bit is set The AD registers

  30. Transmission William Adrovel

  31. SENSOR DATA COLLECTION • 1 A/D Sample from sensor = 12 bits • XXXXXXXX XXXX • 1 Sample will require 2 Bytes for storage • XXXXXXXX XXXX0000 • We will sample 10 Channels every second • 20 bytes of data/second • Data will be stored on 2KB of RAM until transmission • Actual data available for storage will be determined after all programming is finished. Transmission

  32. Efficiency • Transmitting requires more power from our system. • Transmit as little as possible but still be frequent enough to provide constant up to the minute readings from the solar array. • Use onboard RAM to store data until time to transmit • 1.5 KBytes is approximately 75 * 20Bytes • Transmission every 75 seconds • UART for Serial Transmission Transmission (cont.)

  33. What will a S.A.M. Packet look like? • 1Packet: • Start = 2 Bytes • 10 Channels = 20 Bytes • Checksum = 1 Byte • Total = 23 Bytes • 75 Packets*23 = 1725 Bytes /Transmission • Bandwidth needed to transmit our data will be very little. Transmission (cont.)

  34. METHODS OF TRANSMISSION • Wired • DB9 Serial Connection • Simplest and lowest cost • Winter Haven will have this solution • Ethernet Controller • Pros: Direct connection to QuickBeam • Wireless • XBEE • 415 MHz RF Transmitter and Receiver Transmission (cont.)

  35. Types of QuickBeam Projects • Commecial • Office Building • Winter Haven: DB9 Connection • Ethernet • Distributed Solar Arrays • Wireless • Residential • Wired : DB9 or Ethernet Connection Transmission (cont.)

  36. Transmission (cont.)

  37. Mike Telladira Power supply

  38. Distributed 5V dc Power System 6 Hall effect sensors: 5Vdc at 9mA each = 54mA Microprocessor: 5Vdc at 90mA = 90mA RS 232 chip: 5Vdc < 1mA = 01mA _____________________________ Total 145mA

  39. Hybrid Power System 3.3Vdc Buck Key Criteria: 90% efficient Has an Enable pin

  40. Choosing a regulator

  41. Choosing a regulator

  42. Choosing the Buck Regulator LM 22675-5.0 16V to 40V More current But: 1. Greater support from Webench 2. Gerber file -Yes 3. Evaluation PCB -Yes LM 5008 40V to 100V Less current But: 1. Circuit documentation only 2. Gerber file -No 3. Evaluation PCB -No

  43. 5V dc Buck Regulator Circuit Inductor Diode LM22675-5 chip

  44. Why use the Evaluation PCB Inductor LM22675-5 Cinx Diode

  45. Step down methods 1. Voltage Divider 2. Transformer .75w / (eff% * 16V) = 58.9mA 3. In Series Transformer issues: 1. Interlacing 2. Interweaving

  46. Possibility of Series Resistor Conclusion: it may be possible to put the buck regulator in series with an input resistor

  47. Percentage Completed Overall Percentage 71.5%

  48. March 1 All parts acquired • March 3 Power supply finished Sensor circuit finished Microcontroller circuit finished • March 7 Final assembly Software finished • March 15 Software loaded First test of prototype • April 1 Working prototype Project Milestones

  49. Questions

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