Group%20Members:

1
HydroFly Fuel Cell Project

• Group Members
• -Adam Lint
• -Chris Cockrell
• -Dan Hubbard
• Sponsors
• -Dr. Herb Hess
• -Dr. Brian Johnson

2
Final Presentation Outline

• Introduction
• Project Objectives
• Project Specs
• Final Design Solution and Validation
• Individual Components
• Entire System
• Problems Encountered
• Final Steps to Completion
• Budgeting
• Questions

3
Objectives

• Interface a Fuel Cell to the AMPS
• Ensure Safe Operation

4
Functional Specifications

• Overall interface design specifications
• AC signal MUST BE present on the AMPS
• 18-36V DC input from the fuel cell
• Output 208 /- 2 V AC (L-L 3-phase)
• Output frequency at 60Hz /- 0.2Hz
• Power flow of 75W through the interface
• Dimensions fit on cart with dimensions
• 32 x 27 x 18 (2 shelves)
• not including fuel cell, transformers or
  inductor bank

5
Final Presentation Outline

• Introduction
• Project Objective
• Project Specs
• Final Design Solution and Validation
• Individual Components
• Entire System
• Problems Encountered
• Final Steps to Completion
• Budgeting
• Questions

6
DC/DC Converter

• ABSOLPULSE BAP265 - Customized
• Input 18 36 VDC
• Protection Current limiting, thermal fuse,
  reverse polarity protection, 500VDC isolation
  from output/chassis
• Output 120VDC 1
• Protection Current limiting, thermal shutdown
• Power capability 200W
• Efficiency 80 (within 0º 50ºC)
• Cost 318.00

7
DC/DC Converter

• Verification
• Input and output specifications exceeded
• Device operates efficiently at 160W
• not tested at 200W because of power supply
  limitations
• Measured Efficiency 86-87

Picture
8
DC/AC Inverter

• Tier Electronics Custom Package
• Input 80-200VDC
• Output variable 3 phase AC
• Switching circuitry 600V IGBT devices
• Rated current 3A RMS at 5kHz
• TI 2401 DSP fully programmable
• I/O plug
• 15V output, receive and transmit outputs,
  auxiliary inputs and outputs (digital and
  analog).
• Other specifications
• Max output voltage 90VLLwith 120V DC input
• No Previous programming
• Cost 500

9
DC/AC Inverter

• Verification
• Proper operation verified at 120V DC input with
  6kHz switching frequency programmed

Picture
10
Transformers

• 3 single phase transformers (? - Y connected)
• Estimated 75VA rating per phase
• Steps up voltage to 208VLL (RMS)
• Filters PWM output
• Provide a ground isolation
• Experimental Verification (120V output single
  phase)
• Phase A turns ratio 12.6
• Phase B turns ratio 13.2
• Phase C turns ratio 14.3
• The different turns ratios have been accounted
  for in the inverter control. The magnitude of
  each phase can be adjusted to get 120VL-n on the
  output of each phase when connected in ? - Y
  configuration this has not yet been fully
  verified.

11
Inductor Bank

• Provides 142mH per phase for use in controlling
  power flow (experimentally verified).
• Reduces system sensitivity to changes in voltage
  magnitude and/or phase.

12
Zero Detection

• Board designed and built by Dan Hubbard
• Gives a timing reference to the TI-2401 DSP on
  the DC/AC Inverter
• Provides the ability to create a 3-phase signal
  synchronized with the 3-phase system on the AMPS
  and, ultimately, control the power flow to the
  AMPS

13
Zero Detection
14
Zero Detection
Phase 1 Zero Detection Circuits
Vop(1)
Von(1)
Vop(2)
Von(2)
Phase 2 Zero Detection Circuits
Vo1
Vop(3)
Von(3)
Phase 3 Zero Detection Circuits
15
Zero Detection
Vo1(t)
Pulse Sequence 1R 3F 2R 1F 3R 2F
Vo2(t)
16
Zero Detection PCB Board

• 2-layer board Vcc, GND
• Required external power supply 18V
• On-board linear voltage regulator 3.3V
• Inputs (3) 120VAC (3-phase)
• Outputs (2) serial pulse stream, phase 1
  (falling) ref signal

17
Zero Detection - Verification

• Circuitry operates as expected
• Pulse width of approximately 50µs
• Slight error (20µs) accounted for in software

18
Power Flow
Given For 75W power flow and zero reactive
power
To stay within 10 P and Q
19
Software

• Three Main Functions
• Records/Monitors Zero Detection Points
• Gives our PWM a starting point
• Data used to dynamically adjust carrier frequency
  of PWM
• Detects possible faults situations and shuts off
  PWM
• Creates Sine-Triangle PWM
• Triangle wave carrier frequency ( 6 kHz)
• Sine wave generated from sine lookup table
• Values passed into Compare Registers which
  control PWM outputs with user-controlled
  dead-band time (4 us)
• Controls Power Flow
• Delta incrementally added over 100 cycles to
  generate a power flow of 75 W

20
Software
While (1)
System Initialization
Start
Yes
Switch State
Yes
Case 1
Waiting for Pulse
ISR
No
Yes
Case 2
Waiting for Falling Edge
Increment OverflowCounters
No
Yes
Case 3
Calculations
Reset ISR Flag
No
Zero Crossing Analysis
Yes
Case 4
Return
No
Timer 2 OverflowInterrupt
Yes
Case 5
PWM State
No
Default
21
Software
Start
Waiting for Pulse
Phase 1 Falling?
Yes
System Synced
Waiting for Falling Edge
No
Pulse Detected and System Synced?
Calculations
Record Times/Reset Counters
Yes
Zero Crossing Analysis
No
Set Next State
PWM State
PWM Calculations/ PWM Sync Check
Zero Crossing Pulse Stream
Break
Phase 1 Falling Reference Signal
22
Software
Start
Waiting for Pulse
Pulse Ended?
Yes
Record Times
Waiting for Falling Edge
Increment/Decrement Counters
No
Calculations
Set Next State
Zero Crossing Analysis
PWM Calculations/ PWM Sync Check
PWM State
Break
Zero Crossing Pulse Stream
Phase 1 Falling Reference Signal
23
Software
Start
Waiting for Pulse
Calculate Pulse Width
Waiting for Falling Edge
Calculate Time Between Pulses
Half Period?
Calculations
Yes
Calculate Half Period
Zero Crossing Analysis
No
Set Next State
PWM State
PWM Calculations/ PWM Sync Check
Zero Crossing Pulse Stream
Break
Phase 1 Falling Reference Signal
24
Software
Start
Waiting for Pulse
Calculate Actual Zero Crossing with Error Adjust
Waiting for Falling Edge
Increment/Decrement Counters
Calculations
Detect Fault?
Yes
System Shutdown
Zero Crossing Analysis
No
PWM State
Set Next State
PWM Calculations/ PWM Sync Check
Break
25
Software
Start
Calculate Timings/Update Carrier Frequency
Waiting for Pulse
Triangle Wave Rising Edge?
Yes
No
Waiting for Falling Edge
Calculate Phase Counts
Calculate/Load Sin Positions in CMPR Registers
Calculations
Convert to Q15 Format
Turn on PWM Output
Zero Crossing Analysis
Increment Counters
PWM State
Increment Counters
PWM Calculations/ PWM Sync Check
Break
26
Final Presentation Outline

• Introduction
• Project Objective
• Project Specs
• Final Design Solution and Validation
• Individual Components
• Entire System
• Problems Encountered
• Final Steps to Completion
• Budgeting
• Questions

27
Problems Encountered

• Three Main Problems
• Zero Detection Reference Signal Triggered
  Falling Edge instead of Rising
• Edited software accordingly
• Resulted in simpler sine-triangle PWM software
• Transformer Core Losses drew too much current
  from Fuel Cell
• Found smaller transformers
• Recalculated Turns Ratios
• TI2401 DSP Flash Memory Damaged
• Flex-Trace Connection used to program DSP still a
  risk
• Ordered new DSP and is scheduled for delivery on
  Monday
• Expected repair date 12/13/05

28
Final Steps to Completion

• Replace DSP 12/13/05
• Finish interfacing 12/13 12/15
• Upload and test the code for voltage magnitude
  and phase required for synchronization and power
  flow
• Final Demonstration 12/15
• Final Report 12/15
• Users Manual included in final report

29
Budget
30
QUESTIONS?
OUTPUT 208V 2 AC 3-phase Synchronous Freq.
75W
AMPS
AC 3-phase Synchronous Freq.
120V DC 1
Output 208VLL
Fuel Cell
Trans-formers and inductor bank
DC
DC
DC
AC

Y
INPUT 18-36V DC
Control
Special thanks to Greg Klemesrud, JJ, Steve
Miller, Don Parks