Rotor Position Sensors for Hybrid Drives and Electric Drives · ROTOR POSITION SENSOR FOR HYBRID &...

ROTOR POSITION SENSOR FOR HYBRID & ELECTRIC DRIVESJUNE 18th 2013

CONFIDENTIAL – © Electricfil – Reproducti on & disclosure prohi bited without express permission.

Rotor Position Sensors for Rotor Position Sensors for Hybrid Drives and Electric DrivesHybrid Drives and Electric Drives

1

AMAA JUNE 18thOlivier BRUNELELECTRICFIL Automotive



CONTENTS

3 4 5

Rotary Position Sensors

EMPOS Design PerformancesMechanical and electrical interface

2

1

Introduction

6

Conclusion

1 6

32



3

Introduction

1



1.1 EV & HEV as a long term trends

4

CURRENT CARS

MICRO HYBRID

MILD HYBRID FULL HYBRID EV / PHEV

HYBRID VEHICLES ELECTRICAL VEHICLES

Worldwide Market: 71 Mio 94 Mio 103 Mio

Worldwide Market: 71 Mio 94 Mio 103 Mio

Electric motor for vehicles

� Estimated 9 million vehicles by 2020

� Europe (CAFE): 95 g CO2/km

� US (Government): 110 g CO2/km

� 1,x e-motors per vehicles

� Rising market looking for high volume cost

effective & high performance solutions



1.2 Which Electric Motor will be used ?

5

Electric motors for HEV / Plug-in HEV / EV

� Asynchronous electrical motors:Advantages:

– Relative mature technology– no magnet, low cost

Drawbacks:– Low power density– Difficult torque control

� Synchronous electrical motors:Advantages:

– High power density– High efficiency

Drawbacks:– Higer cost– magnet aeging @ high temperature



1.3 Position Sensor for Synchronous Motor Control

� The control system of synchronous motors needs position feedback in order to calculate

the phase currents necessary for obtaining the desired torque with maximum efficiency.

TORQUE REQUEST

BATTERY ELECTRIC MOTORIA IB IC

POSITION SENSOR

INVERTER WITH ECU

POSITION FEEDBACK

θ θ



Rotary Position Sensors

2



2.1 Resolvers

� Advantages

Absolute position information at power on

Robustness

High temperature range

Not sensitive to pollution

High accuracy

� Drawbacks

Potential interference with magnetic stray fields

Requires high excitation currents

Analog output signals

Needs external conditioning circuit

Requires precise positioning of the stator

High cost

8

Provide two AC analog signals representing sine and cosine of θθθθ.



2.2 Electric Motor POsition Sensor = EMPOS

9

� The ideal Rotary Position Sensor for electric motors would have high accuracy and robustness like resolvers, combined with additional features like:

Improved immunity to magnetic stray fieldsFlexible designHigh compactnessReduced costHigh accuracyDigital signal

EMPOS is a new generation rotary position sensor, based on eddy current measurement, that was designed to meet these requirements



EMPOS Design

3



3.1 Working Principle

11



Mechanical & Electrical interfaces

4



4.1 Product Customisation

� Patented pattern of printed coil

windings

� Automated PCB Patterns Generation

� Simple and cost effective target

� Teeth number depends of motor

poles number



4.2 Assembly on Electric motor

� Possible fixation on metallic support without influence on measurement

� Robust to harsh environments of elec. motors and gear boxes

� TW thickness depend on vibrational constraints



4.4 Electrical interface - offer

AS

IC

AR

CT

uCon

tr

EMPOS

AS

IC

EMPOS

MCU

MCU

VDD

Sin

Cos

Gnd

VDD

Out_Sin

Out_Cos

Mod

Gnd

RS

-422

Tra

ncei

ver

AS

ICEMPOS

RS

-422

Tra

ncei

ver

uCon

tr

MCUVDD

SSI_ClkP

SSI_ClkN

SSI_DataP

SSI_DataN

RD

C

uCon

tr

Gnd

Analog interface without carrier signal

Analog interface with carrier signal:

Improved noise immunityStandard RDC

Digital Serial Interface SSI++:

EMC ImmunityNo RDC needed, cost saving

3 O

PT

ION

S



Performances

5



5.1 Sensor accuracy @ low speed

0 50 100 150 200-1.5

-1

-0.5

0

0.5

1

pos ition (°)

erro

r (°e

l)

Linearity error with nominal offset (2.5V) and unity gain

E 1mm @ -40°C 1000rpmE 1mm @ 25°C 1000rpm

E 1mm @ 120°C 1000rpm

0 50 100 150 200 250 300 350 400-1.5

-1

-0.5

0

0.5

1

1.5

pos ition (°)

erro

r (°e

l)

Lineari ty error with nominal offset (2.5V) and unity gain

E1mm @ 1000rpm

E1,5mm @ 1000rpm

0 50 100 150 200 250 300 350 400-2

-1.5

-1

-0.5

0

0.5

1

1.5

posi tion (°)

erro

r (°e

l)

L inearity error wi th nom inal offs et (2.5V) and uni ty gain

E1m m @ 1000rpmE1m m DX0,5mm @ 1000rpm

E1m m DX-0,5mm @ 1000rpm�All effect cumulated linearity error < 1°electrical

.Temperature. Assembly tolerances

Linearity error with temperature change Linearity error with axial displacement of 0,5 mm

Linearity error with radial displacement of 0.5mm



5.2 High speed performance optimisation

Torque error

� Sensor errors influence increase @ high speed

0 50 100 150 200 250 300 350 400-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

position (°)

error (°e

l)

Linearity error with nominal offset (2.5V) and unity gain

E1mm @ 1000rpmE1mm @ 2000rpmE1mm @ 3000rpmE1mm @ 4000rpm

E1mm @ 5000rpm

±1°

at lo

w s

peed

±0.

4°at

hi

gh

spee

d



5.3 EMC Performances

�EMISSION� 150kHz – 2GHz

� CISPR 25 – 48 to 25 dB µV/m

� compliant

�IMMUNITY� RF (200-3000MHz):

• 70V/m to 140V/m

• ISO 11452-2

� AF (15Hz-30kHz):

• 300A/m to 10A/m

• ISO 11452-8

� compliant



Conclusion

6



6.1 Conclusion6.1 Conclusion

21

Their is a high demand in High performance sensor forSynchronous motor

EMPOS is an innovative sensor based on eddy currenttechnology

It offer flexible and easy mechanical integration

It is compatible with 3 electrical interfaces, analog anddigital

The performance has been improved at high speed forOptimum power efficiency



Thank you!Thank you!

Rotor Position Sensors for Hybrid Drives and Electric Drives · ROTOR POSITION SENSOR FOR HYBRID &...

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