Magnetic position sensors aim at electric power steering applications.

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


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）


AgendaAutomotive 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


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


• 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


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 SystemsEnable Automobile OEMs to meet improved steering safety and fuel efficiency requirements


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 LocationAdvanced Magnetic Position Sensors in Electronic Power Steering Applications

C-EPS

P-EPS

R-EPS


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)


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.


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 GrowingAdvanced Magnetic Position Sensors in Electronic Power Steering Applications


Business Drivers for Shift to EPSAdvanced 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


• 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 & emissionsAdvanced Magnetic Position Sensors in Electronic Power Steering Applications

Source: Center for Climate and Energy Solutions


Business Drivers - Loss of Assist in EPSAdvanced 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


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.


Business Drivers - ISO26262 ComplianceThe 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.


Business Drivers – Market Growth in Electric VehiclesAdvanced Magnetic Position Sensors in Electronic Power Steering Applications

HEV - Dominates

BEV – Strongest

Growth


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


Magnetic Position Sensors Play Key Role in EPSTorque 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.


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 SystemsEnable Automobile OEMs to meet improved steering safety and fuel efficiency requirements


Magnetic Position Sensor Key Attributes in EPSAdvanced 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


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 PracticesIntegrated Functionality for Improved Performance, Reliability and Safety

On-Axis Off-Axis


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 ICEnables Efficient EPS Motor Commutation


• 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 ImperativeAdvanced Magnetic Position Sensors in Electronic Power Steering Applications


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


Improved Accuracy - Dynamic Angle Error CompensationAdvanced Magnetic Position Sensors (AS5147P) in High Speed Measurement Applications

Hardware Compensation integrated!

No Software needed!

External HW + SW compensation needed

Magnetic P

ositio

n S

ensor

Syste

m

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


• 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 WorksEnables Low Latency and Fast Refresh Rates

Elimination of Angle Measurement Lag and Fast Refresh Rates (1.9μs) at High RPMs


• 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


Emerging Magnetic Position Sensor Trends in EPSAdvanced 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)


Base EPS ArchitectureEPS System with (TAS) on Steering Column and EPS ECU/Motor Position Sensor (POS) near BLDC Motor


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


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 UpProvide System Power and Cost savings while Improving Vehicle Performance and Safety


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


请通过以下电子邮件地址与我联系：

Please contact me at [email protected]

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!

mailto:[email protected]

http://ams.com/chi/Magnetic-Position-Sensors

http://ams.eefocus.com/


Thank you

Please visit our website www.ams.com

Magnetic position sensors aim at electric power steering applications.

Technology

Transcript of Magnetic position sensors aim at electric power steering applications.