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NEPTUNE Power System Controller

NEPTUNE Power System Controller. Preliminary Design Review Tim McGinnis Dec 4-5, 2003. Functional Requirements. Monitor input and output voltages and currents Control internal & external Loads Measure internal & external load voltages & currents

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NEPTUNE Power System Controller

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  1. NEPTUNE Power System Controller Preliminary Design Review Tim McGinnis Dec 4-5, 2003

  2. Functional Requirements • Monitor input and output voltages and currents • Control internal & external Loads • Measure internal & external load voltages & currents • Detect and isolate external load ground faults • Monitor engineering sensors • Communicate with shore PMACS through DCS • Allow application code to be maintained from shore • Solid state, non-volatile memory • Rugged, reliable, long life • Reasonable packaging • Good thermal characteristics

  3. Controller Specifications PARAMETER SPECIFICATIONS VERIFICATION Input Power Supply Voltage: +5VDC, +/-12VDC Design Digital Outputs > 48 channels Design External Loads 8 @ 48V, 8 @ 400V, 16 deadface relays Internal Loads 16 at 12V and 48V Analog Inputs >40 channels, 12-16 bit Design Voltage Monitoring 10kV, 400V and 48V busses Current Monitoring Backbone 1 @ 10kV External Loads 8 @ 48V, 8 @ 400V, 12 bit Internal Loads 16 @ 12V or 48V, 12 bit Engineering Sensors Tilt, temperature, pressure Ground Fault Monitoring 48V and 400V bus , <10 μA resolution Over-current Protection Programmable by user Testing Data Interfaces Available Design Primary 10/100BaseT Ethernet Secondary RS232 Serial data Memory Non-volatile program code memory Design Software Program code changeable from shore Design

  4. Mechanical Requirements PARAMETER REQUIREMENT COMPLIANCE Thermal Management: Immersed in Flourinert Analysis and Testing Dimensions TBD Design Connectors TBD Design Mounting TBD Design Environmental Requirements PARAMETER REQUIREMENT COMPLIANCE Temperature range per Neptune Power System Analysis and Testing Requirement Document Humidity per Neptune Power System Analysis and Testing Requirement Document EMC and EMI per Neptune Power System Analysis and Testing Requirement Document Shock and vibration per Neptune Power System Analysis and Testing Requirement Document Mission Assurance Requirements PARAMETER REQUIREMENT COMPLIANCE Lifetime 30 years Design, Modeling and Accelerated Life Testing FIT Rate 1000 FITS (?) Design, Modeling and Accelerated Life Testing

  5. Voltage 10 kV bus – 1 400 V bus – 1 48 V bus – 1 Current 10 kV bus – 1 400 V external loads – 8 (4) 48 V external loads – 8 (4) 48 V internal loads – 16 Ground Fault Current Low Voltage Buses - 2 Engineering Pressure – 1 Tilt - 2 Temperature – 3 (?) Total Voltage = 3 Current = 33 (25) Ground Fault = 2 Engineering = 6 (?) Total = ~44 (~36) Note: MARS requirements shown in parentheses Number of Analog Input Measurements

  6. External circuits 400 V loads = 8 (4) 400V load deadface = 8 (4) 48 V loads = 8 (4) 48V load deadface = 8 (4) Internal Circuits 48 V loads = 16 Total External = 32 (16) Internal = 16 Total = ~48 (~32) Note: MARS requirements shown in parentheses Number of Digital Output Controls

  7. COTS Hardware Form Factors • PC-104 • 3.5” x 3.8”, stacking connector • Lots of I/O options • Used in commercial, military and space applications • Reliability data generally not available • ~$2500/system

  8. COTS Hardware Form Factors • 3U VME / Compact PCI • 4” x 6.3”, euro-card connector/backplane • Lots of I/O options • Reliability data available, MTBF’s 100-300 khrs (CPU) • ~$20k/system • available with conduction cooling

  9. COTS Hardware Form Factors • 6U VME / Compact PCI • 9” x 6.3”, euro-card connector/backplane • Lots of I/O options • Reliability data available, MTBF 100-300 k-hrs (CPU) • available with conduction cooling • Large size

  10. Broad ReachEngineering • Builds control systems for satellites and other space applications • Could provide high reliability integrated system • Can provide any level of quality/reliability from prototype-engineering-flight • Development and “flight” system ~$150-200k

  11. 100 FITS = 100 failures in 109 hours = 107 hrs MTBF = 1100 yrs MTBF PowerPC Processor Reliability

  12. COTS Reliability Reality Item FITs MTBF (hrs) Power supply 789 1,267,427 Filter 523 1,912,045 Backplane 348 2,873,563 CPU 3,677 271,929 I/O 5,970 167,495 Total @ 30°C 11,307 88,428 Total @ 12°C 8,698 114, 956 Radstone 3U cPCI data shown

  13. Software • Operating System Choices • DOS • LINUX: GPL, Real Time Extensions • Proprietary: VxWorks, QNX, Lynx, Integrity • Application Code • Most likely C/C++

  14. VxWorks • Commonly used by Military & Space • Recommended by JPL • Board Support Packages (BSP) available for most vendors CPU • Large footprint • Proprietary

  15. GPL LINUX • Gnu Pubic License • Open Source • Compact, high performance • May require BSP and driver development • Full control of OS source code • Can’t be retired • Requires self support • Achievable but takes man power

  16. Real Time LINUX • Shares many features with GPL LINUX • Fast, predictable real-time response. • Guarantees availability of CPU and network resources for critical tasks, even in overload conditions.

  17. Operating System Costs • If Board Support Package (BSP) not available, “free” Linux can be expensive option for low quantities

  18. Action Items • Confirm Functional Requirements of Controller and other relevant sub-systems • Complete Trade Study to compare options • Select Controller hardware • Determine development system requirements • Write specification and procure development system • Start software development • Procure MARS deployment hardware

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