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Magnetic position sensors aim at electric power steering applications.

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Electric power steering (EPS) is the gateway technology to autonomous driving of the future. It is needed to enable advanced driver assistance systems such as side-wind compensation, lane assist/keeping and parking assistance systems. EPS uses a combination of electric motors, actuators, sensors and controllers to give drivers the best steering control for all driving conditions - with Magnetic Position Sensors sensors playing a key role. This event will outline the importance of magnetic position sensors, discuss emerging magnetic sensor trends, such as the inclusion of dynamic angle error compensation and stray field immunity features, to provide higher levels of accuracy performance, and provide an overview of ams’ solutions for this market. Moreover, the talk will discuss how magnetic position sensors are helping to pave the way to electric assisted power steering solutions to meet new government safety and improved fuel efficiency regulations, as well as new industry safety standards such as ISO26262 – ASIL.

Publicada em: Tecnologia

Magnetic position sensors aim at electric power steering applications.

  1. 1. Confidential © ams AG 2015 Magnetic position sensors aim at electric power steering applications Heinz Oyrer, Senior Manager Global Marketing and Strategy Position Sensors, Sensor and Sensor Interfaces, ams AG Automotive Congress, Shanghai, December 2, 2015
  2. 2. Confidential © ams AG 2015 用于电动助力转向应用的 磁性位置传感器 艾迈斯半导体有限公司位置传感器、传感器及传感器接口业务 全球营销战略高级经理 Heinz Oyrer 2015 年 12 月 2 日,国际汽车技术年会(上海)
  3. 3. Confidential © ams AG 2015 Page 3 Agenda Automotive Congress, Shanghai, December 2, 2015 • What is Electronic Power Steering (EPS) and the technology behind it • Who benefits from EPS and why • EPS market growth • Business drivers in EPS growth • EPS manufacturer supply chain • Magnetic Position Sensors play key role in EPS • Technology/business drivers for use of Magnetic Position Sensors in EPS • How EPS technology is paving the way for advanced driver assist systems (ADAS) • Emerging trends/enhancements in Magnetic Position Sensors • Base EPS Architecture using Magnetic Position Sensors • Wrap Up
  4. 4. Confidential © ams AG 2015 Page 4 议程 2015 年 12 月 2 日,国际汽车技术年会(上海) • 什么是电动助力转向 (EPS),它背后蕴藏着什么技术 • 谁会从 EPS 受益,原因何在 • EPS 的市场发展前景 • 促使 EPS 发展的业务因素 • EPS 制造商供应链 • 磁性位置传感器是 EPS 的关键一环 • 将磁性位置传感器应用于 EPS 中的技术/业务因素 • EPS 技术如何为高级驾驶员辅助系统 (ADAS) 奠定基础 • 磁性位置传感器的新兴趋势/发展 • 使用磁性位置传感器的基础 EPS 架构 • 总结
  5. 5. Confidential © ams AG 2015 Page 5 • EPS uses a combination of electric motors, actuators, sensors and controllers to give drivers the best steering control for all driving conditions. • It also gives feedback to the driver – known as the “feel of the road.” • EPS plays a key role in a car or truck’s personality and performance. What is Electronic Power Steering (EPS) Feel of the road
  6. 6. Confidential © ams AG 2015 Page 6 OEMs migrating from Hydraulic to EPS Systems • Hydraulic systems require pump that acts as a constant engine load, which lowers fuel efficiency • With EPS, no pump or engine load, thus increasing fuel efficiency ≈ 3-9%. Heart of EPS system is a DC motor that sits on the Rack, Pinion or Steering Column • Motor provides assist to driver in turning steering wheel • DC Motor type trending from Brushed to BLDC and PMSM Steering ECU receives input sensor data to know how much assist to provide to the Steering Motor Why Shift to EPS Systems Enable Automobile OEMs to meet improved steering safety and fuel efficiency requirements
  7. 7. Confidential © ams AG 2015 Page 7 C-EPS – Motor on Column • Pros – Motor is not exposed to high temps and water • Cons » Motor noise in cabin » Impacts cabin space » Limited to smaller vehicles with light front axial loads P-EPS – Motor on Pinion • Pros – Improved reduction in cabin noise • Cons » Exposed to high temps and water » Can not support heavier vehicles R-EPS – Motor on Rack - Where market is headed • Pros » No motor cabin noise » Flexibility where to mount motor on rack • Cons » Exposed to high temps and water » More costly Types of EPS Systems – Function of Motor Location Advanced Magnetic Position Sensors in Electronic Power Steering Applications C-EPS P-EPS R-EPS
  8. 8. Confidential © ams AG 2015 Page 8 Electric Power Steering Benefits (1) For Drivers, Environment and Auto OEMs EPS Benefits Drivers • Spending less money at the gas pumps. • Minimizes drivers’ carbon footprint • Gives drivers the “feel of the road” • Gives a car or truck its “personality” and performance • Enhances safety and steering control in all driving conditions EPS Benefits Environment • Reduce emissions due to improved vehicle fuel efficiency. • EPS can reduce fuel consumption by up to 6% and CO2 emissions by 8g/km. Estimations show that its EPS systems have helped save almost 3 billion gallons of gas since 1999 (Source: Nexteer Automotive)
  9. 9. Confidential © ams AG 2015 Page 9 Electric Power Steering Benefits (2) For Drivers, Environment and Auto OEMs EPS Benefits to Vehicle Manufacturers • Brushless motor technology means high efficiency, improved steering • Greater quality, technology, performance and value • Modular, compact designs fit the smallest cars to the largest trucks • Seamlessly integrates with OEMs’ vehicle systems • Decreases vehicle weight, increases fuel efficiency • Faster response, rapid design iterations and streamlined supply chain • Paves the way to Advanced Driver Assist “Hitting this significant milestone comes at an exciting time as we celebrate not only how far we’ve come, but also where we’re heading with EPS and other technologies on the path to Advanced Driver Assist Systems and autonomous driving.”, Steve Spicer, Global Product Line Executive – Electric Steering at Nexteer Automotive.
  10. 10. Confidential © ams AG 2015 Page 10 2015 • EPS has 57% of global market in 2015, with emerging markets and big vehicles still using Hydraulic Power Steering (for the moment) • In 2015 global EPS market exceeded 56M units 2020 • Worldwide EPS deployment to grow 82%, between 2015 and 2020 • C-EPS and R-EPS represent 75% of global market in 2020 • EPS will have exceed 80M units in 2020. Source: Nexteer Automotive EPS Market Large and Growing Advanced Magnetic Position Sensors in Electronic Power Steering Applications
  11. 11. Confidential © ams AG 2015 Page 11 Business Drivers for Shift to EPS Advanced Magnetic Position Sensor ICs in Electronic Power Steering Applications Shift in Consumer Demand • Car morphing from a personalized extension to a transportation tool • Affecting how much willing to pay…but…. • Expect high end features, such as EPS, to be standard Increased Regulatory Requirements • Tighter CAFE regulations on fuel efficiency & reduced emissions • Increased mandates on safety-related features; elimination of loss of assist in EPS • High profile EPS related recalls in 2014 from Automobile manufacturers Safety Standard ISO 26262 necessitating need for EPS… • Sensor redundancy in safety critical systems • Enhanced diagnostics at system and even sensor level Market Growth in Hybrid, Plug-in hybrid, and Electric Vehicles • Requiring improved EPS motor control for reduced power consumption & cost Consumer Value, Regulation, Safety and E-Vehicles driving need for lower cost and higher performance sensors in EPS
  12. 12. Confidential © ams AG 2015 Page 12 • U.S. CAFE standards require OEMs to raise average fuel efficiency to 56.2 mpg for new vehicles by 2025; (CAFE – Corporate Average Fuel Economy) • Europe CAFÉ standards require OEM’s to raise average fuel efficiency to 60.6 mpg ≈ 26 km/l for new vehicles by 2025. Translates in CO2 emission reductions to 70 g/km by 2025. Business drivers – improved fuel efficiency & emissions Advanced Magnetic Position Sensors in Electronic Power Steering Applications Source: Center for Climate and Energy Solutions
  13. 13. Confidential © ams AG 2015 Page 13 Business Drivers - Loss of Assist in EPS Advanced Magnetic Position Sensors in Electronic Power Steering Applications National Highway Traffic Safety Administration (NHTSA) Investigated Numerous EPS Related Recalls in 2014 Automotive – OEM1 • Recalled - 1,340,447 vehicles • 3,489 reports of sudden loss of steering power assist while driving • Defect - Buildup of brush debris on EPS motor armature caused motor to stop functioning. Automotive – OEM2 • Recalled 1.1M vehicles in 2014 for power steering failures • NHTSA investigating same issue on another 938,000 cars.  Received 508 complaints from owners with sudden loss of EPS Automotive – OEM3 • NHTSA investigating steering failures on 2 popular vehicle models  Received 24 complaints of lost/diminished power steering assist on 2013 models
  14. 14. Confidential © ams AG 2015 Page 14 Business Drivers – ISO 26262 (Automotive Safety Integrity Level) The Safety Standard for Electrical and/or Electronic systems in Passenger Vehicles First published in 2011, ISO26262 is: • Development process and assessment tool for classifying risk and system safety • Standard framework and vocabulary for hazard elimination • Defines organizational safety management and safety life cycles for auto systems Intended to address three important challenges in today’s automotive technologies: • New electrical/electronic HW and SW safety functionality in passenger vehicles • Increase in content and complexity of electro-mechanical systems and related software • Risk from both systematic failure and random hardware failure ISO26262 is “Technical State of the Art” and sets a Standard for Lawsuits if in Non-Compliance • OEMs legally forced to comply with ISO26262 or risk major law suits.
  15. 15. Confidential © ams AG 2015 Page 15 Business Drivers - ISO26262 Compliance The Safety Standard for Electrical and/or Electronic systems in Passenger Vehicles Vehicle hazards & operational situations are assessed and safety measures are defined for: • Avoiding or controlling systematic failures • Detecting or Controlling random hardware failures • Reducing effects of hardware failures ASIL Classification based on three factors to arrive at one of four levels (A, B, C or D) • Severity (S0..3) • Exposure (E0..4) • Controllability (C0..3) ASIL-D – Highest safety class event; having reasonable possibility of causing a life-threatening or fatal injury, with the injury being possible in most operating conditions, and with little chance of driver intervention/prevention.
  16. 16. Confidential © ams AG 2015 Page 16 Business Drivers – Market Growth in Electric Vehicles Advanced Magnetic Position Sensors in Electronic Power Steering Applications HEV - Dominates BEV – Strongest Growth
  17. 17. Confidential © ams AG 2015 Page 17 EPS manufacturer supply chain (Not a complete list of market players) Advanced Magnetic Position Sensors in Electronic Power Steering Applications EPS Motor Suppliers EPS Sensor Suppliers Tier1 EPS Suppliers Auto OEMs
  18. 18. Confidential © ams AG 2015 Page 18 Magnetic Position Sensors Play Key Role in EPS Torque measurement, Handwheel, and Motor position and control for ASIL-D System Safety Compliance Torque Sensing Requirements [TOS] • Single, Dual, Tri Die Redundancy • Two/Three linear position sensors placed 30o to 90o from each other • Accuracy ≈ 1-2%; with 12 to 14 bits of resolution preferred • Shifting from analog to dedicated digital SENT interface Handwheel Position Requirements [SAS] (On-Axis or Off-Axis) • Dual spur gears with single/dual die angle sensor ICs under each • Accuracy ≈ 1.0o; with 14 bits of resolution preferred • Shift from analog, SPI or I2C to Shared SENT interface Motor Position Requirements (On-Axis) • Dual, Tri, and Dual-Dual redundancy • Fast Digital Interfaces; SPI, ABI, UVW, and PWM • Accuracy ≤ 1.0o; with 12-14 bits resolution • Max RPM  12K to 30K • Fast refresh rates/low latency; << 30µsecs • Electronic Turns Counting • Ability to operate off of Battery • Low Power Mode (<50 µamps/die) Torque and Handwheel Sensor Unit [TAS] EPS Motor Motor position sensor IC controls commutation of brushless DC motor.
  19. 19. Confidential © ams AG 2015 Page 19 Magnetic Position Sensor data to Steering ECU includes: • Hand-wheel position to know direction to turn power steering motor • Torque sensing to measure how much effort the driver needs to turn steering wheel • Motor position for providing motor control, particularly in BLDC motors Magnetic Position Sensors Ubiquitous in EPS Systems Enable Automobile OEMs to meet improved steering safety and fuel efficiency requirements
  20. 20. Confidential © ams AG 2015 Page 20 Magnetic Position Sensor Key Attributes in EPS Advanced Magnetic Position Sensors in Electronic Power Steering Applications Stray Field Immunity • Robustness against unwanted external magnetic stray fields • Reduced BOM - eliminates the need for shielding • Guaranteed safety, reliability and durability through contactless “system-on-chip” Improved Accuracy over Lower and Wider Target Magnetic Field Levels • < ±1.0o over Temp for Rotary Position • < ±1 to 2% over Temp for Linear Position • Operating Magnetic Field Range 5mT to 90mT • Elimination of angle measurement lag at high RPM (DAEC) Redundancy • Dual and Tri Stacked die packaging • Compliance with the latest quality standards i.e. ISO26262 • Zero-defect philosophy/culture Increased Functionality • Interfaces (SPI, SENT, Shared SENT, PSI5) for high performance/reduced wires • On-chip diagnostics for ISO26262 compliance • Turns Counting • Low Power Modes (μamps) • Off-axis
  21. 21. Confidential © ams AG 2015 Page 21 On-axis and Off-Axis Rotary Position Sensing • On-Axis (End-of-Shaft)  No need for linearization; short programming time in production  Mechanicals can be difficult and costly • Off-Axis (Side-Shaft)  Linearization required; longer programing time in production  Mechanicals can be easier and less costly Chopping/Differential Measurements • Reduction in noise and improve accuracy performance • Canceling of parasitic magnetic stray fields Increased Resolution and Refresh Rates • Shift from 8-10bits to 12-14 bits of output resolution for improved accuracy • Faster refresh rates to support higher bandwidth and RPM requirements Enhanced State of the Art Practices Integrated Functionality for Improved Performance, Reliability and Safety On-Axis Off-Axis
  22. 22. Confidential © ams AG 2015 Page 22 Brushless DC (BLDC) Motor is Preferred Choice in EPS as it offers better starting torque and efficiency Controls commutation of a brushless DC motor employed in the system Provides fast and accurate measurements  At startup: provides phase coil information via UVW signals  At speed: provides position measurement via SPI or ABI signals Eliminates need for discrete hall sensors in stator Motor Position Sensor IC Enables Efficient EPS Motor Commutation
  23. 23. Confidential © ams AG 2015 Page 23 • Drivetrain of vehicles becoming partially or wholly electrified • Electromagnetically and mechanically harsh environment • New standards such as ISO11452-8 (immunity to magnetic fields) and ISO26262 (functional safety) Magnetic Stray Field Immunity Becoming Imperative Advanced Magnetic Position Sensors in Electronic Power Steering Applications
  24. 24. Confidential © ams AG 2015 Page 24 Stray magnetic fields in EV and HEV Advanced Magnetic Position Sensors in Electronic Power Steering Applications Position sensor with integrated stray field immunity achieves high accuracy performance even near high current carrying cables
  25. 25. Confidential © ams AG 2015 Page 25 Improved Accuracy - Dynamic Angle Error Compensation Advanced Magnetic Position Sensors (AS5147P) in High Speed Measurement Applications Hardware Compensation integrated! No Software needed! External HW + SW compensation needed MagneticPositionSensorSystem Large lag from angle measurement to reporting Moderate lag from angle measurement to reporting Near zero lag from angle measurement to reporting Elimination of Angle Measurement Lag and Fast Refresh Rates (1.9μs) at High RPMs
  26. 26. Confidential © ams AG 2015 Page 26 • Hall Sensor front_end samples target magnetic field every 110usecs • Four hall sensor elements used to produce differential analog Sine and Cosine signals. • Sin/Cos analog signals converted to digital via 14-bit A/D • Digitized Sin/Cos values fed to Cordic to produce new angle value measurement. • Between 110usecs front_end sample periods Interpolator/DAEC calculates new angle output every 1.9usecs based upon device’s calculation of target magnet rotational rate. How Dynamic Angle Error Compensation Works Enables Low Latency and Fast Refresh Rates Elimination of Angle Measurement Lag and Fast Refresh Rates (1.9μs) at High RPMs
  27. 27. Confidential © ams AG 2015 Page 27 • EPS is the gateway technology to autonomous driving of the future. • EPS technology is enabling the future of “intuitive motion control” with its advanced mechatronic hardware/electronics, software and sensor building blocks. • Safety-critical components play a key role in “Advanced Driver Assistance Systems” – or ADAS How EPS Technology is Paving the Way for ADAS Source: Hitachi IR Day 2015
  28. 28. Confidential © ams AG 2015 Page 28 Emerging Magnetic Position Sensor Trends in EPS Advanced Magnetic Position Sensors in Electronic Power Steering Applications Stray Field Immunity • Robustness against unwanted external magnetic stray fields • Reduced BOM - eliminates the need for shielding • Guaranteed safety, reliability and durability through contactless “system-on-chip” Improved Accuracy over Lower and Wider Target Magnetic Field Levels • < ±1.0o over Temp for Motor and Steering Rotary Position Sensors • < ±1 to 2% over Temp for 1D Linear Position for Torque Sensing • Operating Magnetic Field Range 5mT to 90mT • Elimination of angle measurement lag/faster refresh rates (1.9us) at high RPMs Redundancy • Dual and Tri Stacked die packaging • Compliance with latest quality standards; ISO 26262 (ASIL)/ SEooC • Zero-defect philosophy/culture Increased Functionality • Interfaces (SPI, SENT, Shared SENT, PSI5) for higher performance/reduced wires • On-chip diagnostics for ISO26262 compliance w/ OTP for improved security • Turns Counting and Low Power Modes (μamps)
  29. 29. Confidential © ams AG 2015 Page 29 Base EPS Architecture EPS System with (TAS) on Steering Column and EPS ECU/Motor Position Sensor (POS) near BLDC Motor
  30. 30. Confidential © ams AG 2015 Page 30 Expanding Critical Safety Systems • Increased accuracy and higher internal bandwidths • Package density/technology • Integration of discretes to enable System-in- Package designs • All at lower costs and power Electric Vehicles - Pinnacle of Auto Electrification • Increases EMI/EMC issues • External Magnetically nosier environments • Increased cost and power sensitivity • Higher voltage platforms ISO 26262 Standard is complex and expensive to implement • Who will pay? • How will it affect development cycles? Redundancy in EPS and other Safety Critical Applications Driving Costs • How much more? • Who will pay? EPS Architecture Flexibility with Standardization – Can one size fit all? • Vehicle class: Micros to Luxury SUV’s and Trucks • Rack Power Key challenges driving magnetic position requirements Magnetic Position Sensor ICs offer Four Key Advantages over Discrete Solutions
  31. 31. Confidential © ams AG 2015 Page 31 Magnetic Position Sensor technology will continue to experience strong adoption in EPS/ADAS, and other automotive safety critical and fuel efficiency applications New emission regulations and safety standards, along with EV market growth and shifting consumer demand, are key business drivers Magnetic Position Sensor ICs offer many benefits over other sensing technologies • Superior durability through contactless “system-on-chip” solution • Lower Systems Cost • High Accuracy • Low Power Consumption • Require minimal space • Increased Functional safety via on-sensor diagnostics Wrap Up Provide System Power and Cost savings while Improving Vehicle Performance and Safety
  32. 32. Confidential © ams AG 2015 Page 32 磁性位置传感器技术将继续广泛应用于 EPS/ADAS 以及其它安全关键型和 燃油经济型汽车应用 全新的排放法规和安全标准、EV 市场的增长以及消费者需求的不断变化构 成了关键的业务驱动因素 与其它传感技术相比,磁性位置传感器 IC 具备诸多优势 通过无接触“片上系统”解决方案确保出色的耐用性 降低系统成本 提高精度 降低功耗 最大程度地减少占用空间 通过传感器内置诊断功能提高功能安全性 总结 能够降低系统功耗、缩减成本,同时还能提高汽车的性能和安全性
  33. 33. Confidential © ams AG 2015 Page 33 请通过以下电子邮件地址与我联系: Please contact me at heinz.oyrer@ams.com 请访问我们的登录页面 Please visit our landing page http://ams.com/chi/Magnetic-Position-Sensors 或登录中文页面 or check out http://ams.eefocus.com Thank you for your attention!
  34. 34. Confidential © ams AG 2015 Thank you Please visit our website www.ams.com

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