Quality & Reliability Standards for Electronic Energy Meters / Padrões de qualidade & confiabilidade para medidores eletrônicos de energia Sergio

Transcription

1 Quality & Reliability Standards for Electronic Energy Meters / Padrões de qualidade & confiabilidade para medidores eletrônicos de energia Sergio Abramoff

2 Quality & Reliability Standards for Electronic Energy Meters Sergio Abramoff, Analog Devices, USA Electronic energy meters are being installed at a growing rate to address common problems associated with revenue loss and generation management. These electronic meters offer new functionalities and superior accuracy to electro mechanical meters. However, the accuracy and reliability of the components inside electronic meters are a key concern of utility boards because the failure can have an abrupt effect. When meter manufacturers insist on high quality standards, they ensure that newly installed energy meters will perform accurately over time in various harsh conditions in the field and therefore reduce additional costs incurred due to field failure. This presentation will outline the strict quality and reliability testing done at Analog Devices of the energy measurement IC, which is the core measurement and calculation engine of an electronic energy meter. It will discuss how semiconductor manufacturers can include safeguards in their designs so that components have some resistance to external overstresses as well as testing and statistical methods that ensure that failures do not occur due to the design itself or due to manufacturing process variations. By its nature, an IC does not have moving parts and is not susceptible to the wear out mechanisms typically associated with a mechanical part. However, the IC design, the fabrication process, the assembly process, and the overall product itself all have their own sets of failure mechanisms caused by heat, current, voltage, humidity and temperature extremes. The principal IC failure types and common mechanisms and how IC manufacturers design and test to prevent these failures will be presented. With a basic understanding of IC manufacturing and failure mechanisms, the industry specifications, and supplier data in hand, energy meter manufacturers and utilities can set specifications and requirements for energy metering ICs to ensure that their systems will operate in the field for many years to come.

3 Quality and Reliability Standards for Electronic Energy Meters Presenter: Sergio Abramoff Co Authors: Etienne Moulin, Mark Strzegowski, Lauren Foster Presentation Overview Introduction IC Failures: Causes and remedies IC Reliability standards Case study on IC Life expectancy Conclusion

4 Benefits of Electronic Meters High accuracy Approaching 0.1% error over 10,000:1 current dynamic range Ability to handle higher currents Reliable and Robust (stable over time and temperature) Enable advanced/new functionalities Flexible design One time Calibration Simplified Installation Easy to Manufacture Electronic Energy Meter Technology Electronic Energy Meter components: Mechanical Box, Connections, Current sensor, Stepper Motor Electronic Resistors, Capacitors, Diodes, MOV, MCU, LCD, Energy Metering IC Voltage Sensor Current Sensor ADC ADC ADC ADC Digital Signal Processing for Energy Measurement Energy Measurement IC Watt Power Supply Apparent Data Management RMS Supervisory Others LCDDISPLAY or Stepper Motor

5 Results of Meter Failure Lost revenues Replacement and Repair More inspections Electronic Energy Meter Reliability Reliability of a solution is limited by the reliability of its weakest reliable component Mechanical components failures: Wear out mechanism as friction, dust, rust or demagnetization Reducing the number of Electromechanical components, like Stepper Motor, reduces un noticed lost revenue Electronic component failures Abrupt failures with ON/OFF characteristic Choosing high quality electronic component is critical to insure low failure rate Diagnosis of failure or lost revenue is easy

6 Integrated Circuit (IC) Reliability Time Zero and Early Life Failures are also Quality failures Useful Life Failures: Intrinsic: IC Design, Wafer fabrication, package assembly Extrinsic: User exceeds IC manufacturer maximum stress specifications Wear out Failures are characterized and evaluated to not affect user Bathtub Curve: Failure Rate vs. Time Failure Rate Early life failure Useful Life Wear Out Tim e Time zero and Early Life Failures Caused by: Defects and contaminants during processing Handling of materials used in IC manufacturing Minimized, detected and prevented from affecting customers by: Final Automatic Tests Controlled processes

7 Stress Related Failures 1 Caused by process incorrectly designed, improper materials selected, or mis handling of devices Electrical Over Stress (EOS) failure Mechanical stress Delamination, Cratering, Metal Shearing Delamination Cratering Metal Shearing Stress Related Failures 2 Caused by process incorrectly designed or improper materials selected Mechanical stress Wire breaks, Bond Lifting Humidity Corrosion Bond Lifting Corrosion Minimized by Qualifying materials and processes Quantifying limits of operation

8 Caused by high current transfer of charge during: Manual handling of part Machine handling of part ESD Failures IC manufacturers Specify handling procedures Qualify parts to pass minimum ESD level IC reliability assessment 1 JEDEC International reliability standards to test failure mechanisms Standards developed to set IC reliability requirements MIL STD 883: US Military and Space standards for Hermetic packages MIL PRF 38535: US Military and Space standards for Plastic packaging AEC Q100 standard for Automotive applications Standardization work applicable to Energy Metering ICs

9 IC reliability assessment 2 IC manufacturer Documentation of Quality and Reliability procedures STACK International STACK International is a group of multinational, independent manufacturers who share knowledge to create and follow a quality and reliability standard for electronics Internal specifications for qualification of design, fabrication and assembly processes Documentation of actual qualification testing Documentation of corrective actions Energy Metering IC Life expectancy ADE7755 subjected to 150 C for 3000 hours With Acceleration factor of 179x, the life expectancy correlates to 60 years at operating temperature of 60 C 4 main parameters monitored: Reference Voltage, Gain Error, Current and Voltage channels offset Parameter Distribution over Time shows: Negligible parameter distribution shifts Reference Voltage Parameters maintain datasheet specifications Zero failures!

10 Conclusion Time Zero and Early Life IC failures are minimized by: Final test before shipment to customers High quality processes Useful Life failures are reduced: Controlled quality of materials and processes Characterization of part to set limits of operation (Temperature, Humidity, voltage) International IC reliability standards define test methods and limits to obtain reliable ICs IC manufacturers should have Internal specifications and procedures to insure reliable ICs are constantly produced and shipped to customers

11 Biography Speaker: Position: Company: Country: Sergio H. Abramoff Territory Manager South America Analog Devices, Inc. (ADI) USA Holding a B.S.E.E. since 1983, Sergio has been working with ADI for the last 10 years. During this time, Sergio has been technically involved with different flavors of technologies, customers and products within ADI. In particular, he has been working along with the Energy Metering Group since it started. Prior to working at ADI, he has worked for many years in Sid Microelectronics, where he held several management positions.

12 Company: Analog Devices, Inc. (ADI) Company Background Information Country: USA Analog Devices is a leading manufacturer of precision high performance integrated circuits used in analog and digital signal processing applications including energy metering. The company is headquartered in Norwood, Massachusetts and employs approximately 8,600 people worldwide. It has manufacturing facilities in Massachusetts, California, North Carolina, Ireland, the Philippines, Taiwan and the United Kingdom. Analog Devices' stock is listed on the New York Stock Exchange and the company is included in the S&P 500 Index.