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Group 5 Alec Calhoun, Patrick Neely, Eric Eiermann, Brett Burleigh

Group 5 Alec Calhoun, Patrick Neely, Eric Eiermann, Brett Burleigh. Introduction. Let’s Make Green Power More Practical Hurricane / Natural Disasters Emergency Power Portable Power / Remote Power Ultimately: Ease of Use to bring Green Power to the masses!. Features.

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Group 5 Alec Calhoun, Patrick Neely, Eric Eiermann, Brett Burleigh

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  1. Group 5 Alec Calhoun, Patrick Neely, Eric Eiermann, Brett Burleigh

  2. Introduction • Let’s Make Green Power More Practical • Hurricane / Natural Disasters • Emergency Power • Portable Power / Remote Power • Ultimately: • Ease of Use to bring Green Power to the masses!

  3. Features • Flexibility and Portability • Familiarity • Efficiency and Safety

  4. Features • Flexibility • Multiple Input Types, Multiple Output Types • Inputs are interchangeable • Solar • Wind • Generator to Harness Human Power • Portability for Remote Power applications • Use outside of the home, such as on an RV • Storable in a closet

  5. Features • Familiarity • Common interfaces that the public has seen before • Easy to use: • Operate the Display • Press to Toggle • Display the Green Box’s performance data

  6. Features • Efficiency and Safety • Harness as much power generated as possible • Cut back on waste on electronics not being used • Circuit Breakers, relays, and manual switches • Prevents damage to the system and loads • Protect user • Microcontroller to control fan and buzzer: • Fan will automatically turn on • Buzzer will alert user of high temperature levels

  7. Specifications • Store a total of 100Ah that may come from 1, 2, or 3 12V DC power generation devices at any one time • 12V DC, 15A output receptacle • 5V DC, 500mA USB output receptacle • 110V AC, 60Hz, 9A output receptacle • 24” wide x 24” long x 22.5” high • Approximately 125 lbs • Wheels for ease of portability

  8. Block Diagram

  9. System Overview • Inputs • Charging • Energy Storage • Outputs • System Controls • System Monitoring

  10. Inputs • Solar, Wind, Human Power and others • User selects desired method(s) of power generation • Adaptable for Various locations, climates, and seasons • 3 Inputs chosen are for Demonstration and Testing purposes only • Any inputs which meet requirements can be used

  11. Input: Requirements • Any DC input that is above the battery voltage • Efficiency reduced above highest bulk charge voltage • 35 continuous amps per input • If AC inputs are desired, the user must externally convert power into DC by: • Using a full wave rectifier and large capacitor

  12. Input: Solar Panel Model: SUN-100 (M) • Specifications: • Monocrystalline Silicon • Size (L x W x D): 42-1/2” x 31-3/8” x 1-3/8” • Weight: 30 lbs. • Cost: $2.78 per Watt

  13. Input: Solar Panel • Electrical Characteristics • Voc: 23.60 Volts • Isc: 6.30 Amps • Vmp: 18.10 Volts • Imp: 5.53 Amps

  14. Input: Wind Turbine Southwest Windpower Air-X Turbine • Specifications • Size (L x W x H): 27” x 15” x 9” • Weight: 17 lbs. • Durability: 110 mph survival wind speed • Blades can be removed for easy transport

  15. Input: Wind Turbine • Electrical Characteristics • Cut in Windspeed = 8 mph • Observed current with electric drill = 5.8 Amps

  16. Input: Human Power AMETEK PMDC Motor • Specifications: • Low RPM for desired voltage • Weight: 7 lbs. • Cost: $170 • Electrical Characteristics: • Rated for 38 V at 1100 rpm • 14.5 V at approximately 420 rpm Human Power Mechanism • Fabricated from an old bicycle and motorcycle chain • Final Gear Ratio: 3.25:1 • Observed Current: 5.2 Amps (Max), 2.1 Amps (Average)

  17. Charging System • Charging one battery with 3 inputs of different voltages presents a problem • Input with highest voltage = only contributor to charging • If blocking diodes are not installed, inputs can destroy each other • Two options are possible • Voltage regulate each input to 14.5V, and then combine together into one large charge controller • Use three separate small charge controllers

  18. Voltage Regulation vs. Controllers • Why 3 charge controllers is the best option: • Voltage regulation built into each controller • Pre-designed and tested allowing for easy integration • Same price as building 3 voltage regulators and using a large charge controller • Failure of one controller will still allow 2/3 to operate • Most common setup in hybrid systems

  19. 3-Stage or MPPT C.C.’s • There were two types of charge controllers considered • Maximum Power Point Tracking • 3 Stage Pulse Width Modulation • MPPT C.C.’s use transformers to turn high voltage, low current into a lower target voltage with increased current • Boosts efficiency greatly when input’s voltage is well above battery voltage • 3 stage C.C.’s use PWM to match the desired voltage • All power above desired voltage level is wasted

  20. 3-Stage or MPPT C.C.’s • Although MPPT has excellent efficiency (above 92%) The extra cost was not a good value. • 3 Stage Charge Controllers were chosen because: • Cost 40% as much as comparable MPPT C.C. • The user can buy more generators (solar panels or wind turbines) with the money saved • The cheaper 3 Stage CC has the same efficiency as MPPT CC when input voltage is close to target voltage

  21. Charge Controllers • Model: Xantrex C-35 • Voltage: 12V or 24V • Current Rating: 35 amps • Weight: 2.5 Pounds • Size: 8 x 5 x 2 Inches • Cost: $85 Each • -Features: • Microprocessor Control • Pulse Width Modulation • 3 Stage Charging • AGM Compatible

  22. Green Energy • Energy Storage Requirements • Store all the energy generated in a single day • Full Charge & Discharge Cycle = Maximum Efficiency • Able to be charged quickly • To harness all available power • Need to calculate the size of battery • Reduce cost • Increase life of battery

  23. Green Energy

  24. Battery • 3 Types of Lead Acid Batteries • Starting • Large Current, but only for Short Duration • Would only last 30 days in our application • Marine • Thicker Plates • Durable, but still inferior • Deep Cycle • Thickest Plates • Most durable of all Lead Acid Batteries

  25. Battery • 3 Types of Deep Cycle Batteries • Flooded, “Wet” • Battery Acid / Fumes can escape into consumers home • Cannot be shipped UPS, USPS, and others • Gel Cell • Heaviest • Most Expensive • Absorbed Glass Mat • Fast Recharge • Will not spill acid, even if cracked • Slow Self-Discharge Rate • Most popular Choice in Alternative Energy

  26. AGM Battery • Werker 100Amp Hour • Absorbed Glass Mat, Deep Cycle • Voltage: 12 Volts • Rating: 100 AmpHours • Dimensions: 14 x 10 x 8 inches • Weight: 74 Pounds • Cost (New): $280

  27. Outputs • From Inverter: • 110 Volt, 60 Hz AC, 9 Amps (Max) • 12 Volt DC, 15 Amps (Max) • From Microcontroller: • 5V DC USB Connector, 500mA (Max)

  28. Output: Inverter • Three types of Inverters considered • Square Wave • Inefficient • High Total Harmonic Distortion (THD) • Inductive loads should not be used due to abrupt changes in the waveform • Modified Sine Wave • Still inferior due to THD and abrupt changes • Pure Sine Wave • Produces voltage Identical to household outlet • Any load can be connected • Expensive and Complex Design

  29. Output: Inverter • Power Express PE-1000PSW • Continuous Power: 1000 Watts • Surge Power: 2000 Watts • Voltage: 110V +/- 10% • Frequency: +/- 2% 60 Hz • Dimensions: 13.5x9x3.5 in • Cost: $290 • Features: • Low Battery Shutdown (10.5 Volts) • Overload Protection

  30. The Green Box Control Board • Requirements: • Drive LCD Display • Process Digital I/O Devices • Process Analog I/O Devices • Provide All Voltages Required to Power Devices(12V DC, 8V DC, 5V DC)

  31. Microcontroller • Model: Atmel Atmega168 • Chosen Due to Ability to Meet Our Diverse Needs and C-Programming • Up to 20MHz speed(we have a 14.75MHz oscillator) • RISC architecture • C Programming • 16 KB Flash (Program) Memory • 512 Bytes EEPROM (Data Retention) Memory • 23 Configurable I/O lines • 6 10-bit Analog-to-Digital Converters(ADC) (0-5V = 0-1023)

  32. LCD Display • Model: Unitech UC-204 • Chosen Due to Compatibility /Easy Interfacing with Atmel Atmega 168 • 4 Line x 20 Char. Display • 5V DC Supply • Integrated Hitachi HD4478U LCD Controller (4-bits data, 2 control lines: Enable and Register Shift) • C Libraries Available 4 screens of information are toggled through using red pushbutton, which is an input to the microcontroller.

  33. Software: LCD Functions • C Library Simplifies Comm. to LCD Controller • Functions Used: • void lcd_init(); //enables and configures the display • void lcd_home(); • void lcd_write_string(const char *x); • void lcd_line_two(); • void lcd_line_three(); • void lcd_line_four(); • int lcd_putchar(char x, FILE *stream); //used to create output stream to LCD controller(fprintf)

  34. Analog I/O – Current Sensors • Model: Micro Switch CSLA2CD Requirements: • Hall Effect Sensor (varies output voltage due to changes in magnetic field) • 12V DC Supply(or less) • 0-5V DC Output • Ability to Sense Both AC and DC CSLA2CD: • 5.4 – 13.2V DC Supply • Output = Vs/2 (+/- .033V per A) • Works for both AC and DC • Using our configuration, max current possible to sense is 30.30A. (1V/.033V)

  35. Software: Current Sensors • We Supplied Sensors with 8V, therefore it will provide 4V @ 0A • It changes output at rate of .033V/A. • Our 10-bit ADCs range from 0-1023 at 0-5V • Calculation of 1 step in ADC to Amps: • (0.033V/1A)* (1024 steps/5V) = 6.7584 steps/A • Therefore 1 ADC step = .148A

  36. Software: Current Sensors Challenges: • 1. DC current makes the ADC value increase, while AC current makes the ADC value oscillate. • 2. “Zero” value must be periodically recalibrated due to external magnetic fields. • Functions Used or Developed to Handle Current Sensors: • adc_init(x) //selects the proper ADC • adc_read() //returns raw 0-1023 value from ADC • sampleToAmps(samplecs1, zerovalue) //converts ADC to DC Amps • sampleToAmpsAC(samplecs4, zerovalue) //converts ADC to AC Amps

  37. Software: Current Sensors Auto-Calibration of the Current Sensors: • Each time processor is powered up current sensors are “zeroed” on first pass of program • Accomplished by taking 200 ADC samples with all current inputs/outputs unplugged. These 200 samples are averaged and that is set as the “zero” point for that current sensor: adc_init(1); // take 200 current samples and average them temp_avgcs1 = 0.0; for(ics1=0; ics1<200; ics1++) { last_samplecs1 = adc_read(); // add this contribution to the average temp_avgcs1 = temp_avgcs1 + last_samplecs1/200.0; zero_cs1 = temp_avgcs1; }

  38. Analog I/O – Battery Voltage • Simple Voltage Divider Circuit: Requirements: • Needed to scale down battery voltage to 0-5VDC for ADC to read it. Used 4.7kOhm and 15kOhm resistors • Changed 0-20V range to 0-4.77V • Functions Used or Developed to Handle Battery Voltage: • adc_init(x) //selects the proper ADC • adc_read() //returns raw 0-1023 value from ADC • sampleToVolts(samplebv) //converts ADC to Volts • 100 samples are taken and averaged to stabilize the reading of the Battery Voltage.

  39. Analog I/O – Temperature • Model: National Semiconductor LM34 Requirements: • 5V DC Supply • 0-5V DC Analog Output LM34: • 5 – 20V DC Supply • Output = 10.0 mV/degree F • Low Cost / Small TO-92 Package • Functions Used or Developed to Handle Temperature: • adc_init(x) //selects the proper ADC • adc_read() //returns raw 0-1023 value from ADC • sampleToFahrenheit(sample) //converts ADC to degrees(F) • 100 samples are taken and averaged to stabilize the reading of the Temperature

  40. Battery Voltage &Temperature • Battery Voltage and Temperature are both displayed on the LCD Display. • Temperature is also used to control fan and buzzer: • Fan is turned ON when box temperature exceeds 80 degrees. • Fan turns OFF when temperature goes below 79 degrees. • Buzzer is turned ON when box temperature exceeds 84 degrees. • Buzzer turns OFF when temperature goes below 83 degrees.

  41. AC Output-To-Date Challenges: • 1. Algorithm for determining wH. //handle updating of AC output-to-date: winst = temp_avgcs4 * 120;//convert A to w(instantaneous) //add to total kwh output-to-date //(factor needs to be base on final program scan time)(inital guess is 50ms, .050s) whsavedtemp = whsavedtemp + (winst * .150 / 3600);. • $ saved is calculated in real time from wH, using national average cost(12.05c/kwH).

  42. AC Output-To-Date Challenges: • 2. The total wH saved is stored in EEPROM, so it is preserved during power loss. Taking care to not write to EEPROM on every program cycle, which would be very slow. whsavedtemp = eeprom_read_word((uint16_t*)E_TOTALWHSAVED); //check to see if update is needed for EEPROM wh counter(every 1 wH): whcompare = eeprom_read_word((uint16_t*)E_TOTALWHSAVED); if ((whsavedtemp - whcompare) > 1){ eeprom_write_word((uint16_t*)E_TOTALWHSAVED,whsavedtemp); }

  43. PCB Design - Layout • Used ExpressPCB software • Designed with Terminal Blocks since most devices are remote(current sensors, LCD display, fan) • Provisions for laptop connection to do in-circuit programming

  44. PCB Design - Schematic • Used ExpressSCH software • Links to PCB layout in ExpressPCB software to help detect errors before production

  45. Testing • Five Testing Categories • Input • Charging System • Output & System Performance • Device Protection • Current Sensors • Testing Equipment Utilized • Fluke Clamp Meter • Craftsman Digital Multimeter • Tektronix Oscilloscope

  46. Input Testing • Key Objective: verification that all inputs were functional and operated according to manufacturer specifications • Testing Results: • Solar Panel: Multimeter was used to determine Voc & Isc • 23.60 volts, 6.30 amps • Human Power Generator: Multimeter was used to verify that the human power mechanism could drive the generator fast enough to produce a voltage above 12 volts • Maximum Voc produce was ≈28 volts • Wind Turbine • Circuitry prevented open circuit testing, therefore the “back of the truck” method was utilized for initial testing • With battery as load were able to generate a maximum of ≈17 amps at 12 volts • Subsequent testing was performed using a corded drill to simulate an ≈ 18 mph wind generating 72 watts • Inputs were later used as testing devices for The Green Box

  47. Charging System Testing • Clamp Meter and Multimeter were used to periodically record the battery terminal voltage and current provided by inputs to ensure proper charging process • Charging Test Results • Inputs used: Solar Panel (constant) and Wind Turbine (intermittent) • 1st 7 hours spent in Bulk Stage • Final hour spent in Absorption Stage

  48. Inverter & Output Testing • Key Objective: Verification that AC output maintains a pure sine wave under various stresses • Oscilloscope was used to measure frequency and the Vrms waveforms under varying loads • Initial inverter testing performed while battery voltage was 12.5 volts (> 80% charge) • Procedure was repeated with battery voltages of 12.1 volts (≈ 50% charge) & 11.7 volts (< 30% charge) • Testing revealed that inverter, when on, was consuming ≈ 21-30 watts from battery • A relay and switch were installed for convenient inverter disconnect when not in use

  49. Inverter & Output Testing Battery Voltage: 12.6 volts (> 80% charge) No Load 300 Watt Load 720 Watt Load 720 Watt Load w/ 15 Amps from Inputs

  50. Inverter & Output Testing Battery Voltage: 11.7 volts (< 30% charge) No Load 300 Watt Load 720 Watt Load 720 Watt Load w/ 15 Amps from Inputs

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