CAPS FID Interface Board Midterm Presentation I Odai Ali James Owens Joshua Roybal

Background 2

Overview Funded under the Future Renewable Electric Energy Delivery and Management Systems Center (FREEDM Center) FREEDM Center goal to develop green energy hub Need a fault isolation device (FID) in the green energy hub to act as switch for different parts of the network FID developed jointly NCSU solid state CAPS mechanical switch 3

Problem Statement FID is split into two pieces Fast mechanical switch (FMS) Solid state power electronics Need a controller to bridge the gap of communication between these two systems 4 NCSU Controller CAPS Interface Board

Operational Description Two areas of communication Internal Triggering the mechanical switch Determining the state of the switch External Measuring pressure of FMS chamber Measuring temperature of switch frame Broadcasting information to NCSU’s controller and to the rest of the FREEDM Green Energy Hub 5

Needs and Requirements Analysis 6

Capabilities Required: Internal communication interface between power electronics and FMS External communication interface to rest of green energy hub Integration of design onto single PCB System must be reliable in opening and closing the mechanical switch Desired: A standalone operation mode 7

Weight of Capabilities Internal Communication External Communication Integration into Single Board System Reliability Geom. Mean Norm. Weight Internal Communication 13/252/ External Communication 2/3131/ Integration into Single Board 1/51/311/ System Reliability 3/

Divide and Conquer Design 9

Hardware Requirements and Design 10

Hardware Requirements Requirement NumberDescription HREQ-001Custom print PCB to house all hardware HREQ-002One digital input signal to trigger FMS HREQ-003One digital output signal for FMS state HREQ-004Thermocouple to read chamber temperature HREQ-005Pressure gauge to read chamber pressure quality HREQ-006Strain gauge to determine state of switch HREQ-007Electrical connector to feed through to vacuum chamber HREQ-008Power amplifier to drive piezoelectric element HREQ-009DAC to provide waveform to power amplifier from DSP HREQ-010PSU to power interface board and DSP production board 11

Hardware Block Diagram 12

Hardware Performance Specifications Specification NumberDescription HPSPEC-001Communication between NCSU and CAPS interface boards must operate at no less than one read/write per ms HPSPEC-002Broadcast temperature and pressure reading update rate must be no less than one reading per hour HPSPEC-003Bit stream communication to DAC must operate at MHz symbol rate (150 MHz bit rate) HPSPEC-004DAC precision of 16 bits per sample HPSPEC-005DAC sample rate capability of at least MHz HPSPEC-006Piezo drive amplifier V and 0-30 A capabilities HPSPEC-007Strain gauge sampling conducted at 30 MHz HPSPEC-008Strain gauge amplifier output of V HPSPEC-009Thermocouple sampling conducted at 30 MHz HPSPEC-010Thermocouple output of V 13

Software Requirements and Design 14

Software Requirements Requirement NumberDescription SREQ-001Software layer to translate input signal from NCSU into drivable signal output to DAC SREQ-002Software layer to read serial data from the pressure gauge display, and analog signals from the strain gauge and thermocouple SREQ-003Software layer to analyze strain gauge readings, determine state of switch, and feedback state to NCSU SREQ-004Software layer to interpret and broadcast serial data from thermocouple and pressure gauge amplifiers 15

Software Block Diagram 16

Software Performance Specifications Specification NumberDescription SPSPEC-001Main loop must run in one ms to allow for HDSPEC-001 SPSPEC-002Piezo drive signal length must not exceed 1 ms SPSPEC-003Strain gauge analysis code must run in under 667 ns per strain gauge sample (or total of 100 single cycle instructions) SPSPEC-004Temperature and pressure reading must be sampled at least once per hour 17

Test Plan 18

TEST-001: Thermocouple Reading The thermocouple itself and the communication to the DSP controller need to be tested Proposed Plan: Place an additional verification thermocouple in the chamber (read with a multimeter) Take a reading at ambient Heat the chamber with heater tape for 10 minutes Take another reading Compare the readings on the two thermocouples Pass with error of < 5 % 19

TEST-002: Pressure Reading The communication from the pressure gauge display to the DSP needs to be tested Proposed Plan: Use the pressure gauge display as a control Take an initial reading Pump the chamber overnight for 12 hours Take another reading Compare the readings on the pressure gauge display and the DSP Pass with error of < 5 % 20

TEST-003: Switch Actuation The communication path of DSP -> DAC -> Power Amp -> Piezoelectric actuator needs to be tested Proposed Plan: Conduct the test outside of the vacuum chamber (for visual confirmation) Trigger the DSP via a GPIO pin Actuate the switch Verify visually that the switch has moved with calipers 21

TEST-004: Strain Gauge Steady State Classification The state of the switch needs to be quantified with feedback input from the strain gauge Proposed Plan: Actuate the switch Save the strain gauge output and analyze with MATLAB Constrain bound on output slope for when steady state has been reached 22

TEST-005: Strain Gauge Steady State Verification The work conducted in TEST-004 needs to be verified Proposed Plan: Actuate the switch Use the oscilloscope to measure the DSP digital pin switch state Verify that the pin is pulled high when the switch is visually finished actuating 23

Methodology 24

Scheduling Work accomplished via a divide and conquer approach Odai: Software design Josh: Hardware design James: Administrative and systems integration Plan for completion of working interface board by end of December 2015 Plan for testing board integration in early January

Conclusion 26

Questions 27

Backup 28

FID Interface Board Block Design 29 Power amplifier: AE Techron LVC 3622 Open Power supplyPower supply (208 V) Thermocouple amplifier Strain gauge bridge/amplifier RS 232 Serial 0-10 V analog Closed Temp Vacuum Spare Thermocouple Strain gauge Vacuum gauge Piezoelectric actuator DSP board (TI CCS for programming) TI DSP TMS320F28335 Display unit Analog Non evaporable getter

Gantt Chart 30

Gantt Chart 31

Gantt Chart 32

Analysis Algorithm 33 Input strain gauge samples at 30 MHz via ADC Calculate slope of curve at constant data point separation When slope under given threshold, switch is at steady state Using slope method to eliminate different bias levels May need to smooth input data via MA filter to eliminate false slopes

Temperature at 100 A 34

Temperature at 500 A 35

Temperature at 1000 A 36

Previous Gen FID 37 There are four main parts in the hybrid FID: FMS: fast mechanical switch AB: auxiliary breaker MB: main breaker MOV: metal oxide varistor Opening procedure of the hybrid FID