automotive power shen s2
TRANSCRIPT
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Emerging Issues in Automotive
Power Electronics
John ShenElectrical and Computer Engineering Department
University of Michigan-Dearborn
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Outlines
Overview of Power Electronics Power Semiconductor Devices
Power Electronic Circuits
Automotive Case Studies
Emerging Issues
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Overview of Power Electronics
What is power electronics? General applications
Automotive applications
Classification of power processors and converters
Interdisciplinary nature of power electronics
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What Is Power Electronics?
Power electronics: to control and process electricalenergy efficiently.
Power electronics: an enabling technology for
computer, communication, industrial control, andautomotive technologies.
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General Applications
Power suppliesBattery chargers
RefrigerationLighting & heating
ComputerCommunication
Consumer
Pumps/compressorMachines & toolsProcess control
Factory automation
IndustrialCommercial
HVDCStatic var comp.Renewable engr.Energy storage
Utility systems
AircarftSpace shuttle
SateliteMilitary
ArospaceMilitary
EV/HEVBattery chargers
Load controlTrains & Metro
TransportationAutomotive
Power ElectronicsApplications
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(Source: Hitachi)
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Voltage and Current Ranges
1 10 100 1000 10000
Voltage (Volts)
1
10
100
1000
0.1
0.01
Current(
Amperes)
Digital
Analog
Disk
Drives
Display Drives
Telecommunication
Automotive
Lighting
Motor
Control
Traction
HVDC
PowerSupplies
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Automotive Applications
PowertrainFuel injection
IgnitionTransmission control
Cooling fan control
Electronic throttle controlAlternator rectifier
Voltage regulatorIntegrated starter generator
EV/HEV traction drive
Battery charger
Body ElectronicsHeadlamp control
HIDPower seatPower door
Power window
Windshield wiperDefrosting/defoggingClimate control
Instrumentation
Chassis & SafetyElectrical Power steering
ABSTraction controlActive suspension
Airbag ignitor
E/E ArchitectureMultiplex wiring
Active power managementTelematicsMobile media
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Military Vehicle Applications
Hybrid electric drivetrains to improve fuel economy
Fuel cell: drivetrain and auxiliary power Next generation electrical architectures: 42V and beyond
X-by-wire applications
Mobile power generation
Central
Power
Processing
Unit
110V AC220V AC12/24/42V DC
..
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Classification of Power Converters
AC/DC converters (rectifiers) DC/AC converters (inverters)
DC/DC converters
AC/AC converters
ConverterInput:
AC or DC
Output:
AC or DC
Control
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Interdisciplinary Nature of PowerElectronics
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Power Semiconductor Devices
Ideal power switches Diodes: rectifying, freewheeling, and clamping
Power MOSFET: the low voltage load driver
IGBT: the high voltage power switch
Power ICs and emerging device technologies
SiC technology
Power losses and thermal management
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Examples of Using Power Switches
Loads: lamps, solenoids, motors, ignition coils, etc.
+ v -
i
- v +i
High-Side Switching Low-Side Switching
Load Load
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Ideal Power Switches
Block large forward and reversevoltages when OFF (i=0).
Conduct large currents when ON (v=0).
Switch between ON and OFFinstantaneously.
Ease of control
Rugged and reliable
Low EMI during switching
i=0
+
v
-
i
+
v=0
-
ONOFF
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Non-Ideal Characteristics:Breakdown Voltage Rating
A real switch can only block a certainamount of voltage (voltage rating) when
OFF. The switch will conduct currents if
the limit is exceeded (breakdown). Most switches can only block voltages in
one direction.
i
+
v
-
OFF
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Non-Ideal Characteristics:Current Rating and Conduction Loss
A real switch always has some resistanceand can only conduct a certain amount of
current (current rating) when ON. The
switch will overheat if the limit isexceeded.
Conduction loss: p = i*v=i2*R
i
+
v
-
ON
R
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Non-Ideal Characteristics:Switching Speed and Switching Loss
A real switch takes a certain amount of time toswitch between ON and OFF states (switching
time or switching speed).
Switching loss: p(t) = i(t)*v(t)
i
v
ON ONOFF
Ideal Switch
i
v
ON ONOFF
Real Switch
toff ton
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Semiconductor Power Devices
Diode Bipolar Junction Transistor (BJT)
Power MOSFET
IGBT
GTO
Thyristor
Power ICs and SmartPower devices
SiC Devices
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Diodes
Diode: a two-terminal uncontrollable device Automotive applications: rectifying (alternator),
clamping (transient voltage suppression), and
freewheeling (electric drivetrain inverters)
P N
+ V -
IV
I
Forward
(ON)
Reverse
(OFF)
Breakdown
ON voltage
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Switching Characteristics
Reverse recovery (turn-off) Forward recovery (turn-on)
Fast and soft
i
Ideal diode current
Real diode current
Recovery time trr
IRM
ONOFF
Recovery charge Qrr
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Zener Diodes
Operating in breakdown mode Used as transient voltage suppressors (TVS) to
reduce EMI or provide load dump protection.
Circuits
+
v
-
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Power MOSFET
A three-terminal controllable device Driver (or switch) for low-voltage loads
Voltage ratings: 30-60V for 14V systems and 75-
100V for 42V systems
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DC Characteristics
Threshold voltage Vth
Drain-source breakdown voltage V(BR)DSS
Drain-source resistance RRDSON
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Switching Characteristics
Charge and dischargecapacitors
No charge storage time
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Safe Operating Area (SOA)
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Avalanche (UIS) Energy Capability
The ability to survive the
harsh automotive EMIenvironment
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MOSFET Device Structure
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Rdson and Current Rating
Current rating is determined by the Rdson and
thermal design of the MOSFET. Larger die size=>lower Rdson @ higher cost
Trench MOSFET technology provides lower Rdson.
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Insulated Gate Bipolar Transistor(IGBT)
Excellent power switch for HV circuits (>500V) lower conduction loss and high current capability
Medium switching speed (
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IGBT vs. MOSFET
IGBT:
Bipolar (two carriers) Conductivity modulation
Medium speed
MOSFET:
Unipolar (single carrier) Ohmic resistance
High speed
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DC Characteristics
Collector (C)
Emitter (E)
Gate (G)
iCE
+vCE
-+
vGE
-
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DC Comparison: IGBT vs. MOSFET
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Switching Characteristics
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Switching Comparison:IGBT vs. MOSFET
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Short Circuit Capability of IGBT
The ability to survive a short-circuit condition fora certain amount of time.
Extremely high voltage, current, and power.
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Power ICs & SmartPower Devices
Power ICs or SmartPower devices integrate powerdevices with control, diagnostic, and protective
functions into a single chip or package.
Tradeoff between function integration & cost Usually limited to moderate power applications
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Example: Smart High-Side Switch
(Infineon BSP752T)
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Emerging Power Semiconductors
MOS-gated thyristors (MCT, MCCT, etc.) SiC technology
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SiC: Electrical Properties
Wide bandgap semiconductor material
(SiC: 3-3.3eV vs. Si: 1.12 eV)
High electric breakdown field
(SiC: 1.5-4e6 V/cm vs. Si:2-8e5 V/cm)
High carrier mobility
High thermal conductivity
Specific on-resistance of a SiC device is 1/300th that of an
equivalently rated Si device Ideal for high power, high temperature, and high frequency
applications (e.g., electric drivetrains)
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SiC: Materials
Many polytypes: 6H, 4H, 3C, etc. 4H-SiC for high power devices (higher electron
mobility)
50mm 4H- and 6H-SiC wafers available and75mm SiC wafer capability demonstrated.
Micropipe defect is the limiting factor
Both bulk and expitaxial SiC wafers needed
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SiC: Power Device Demonstration
Diodes: 2.5-4.5V, Vf of 4V at 1000A/cm2
Power MOSFET: 550V, 25mO-cm2
Thyristor: 900V, Vf of 3.9V at 625A/cm2
SiC BJT, IGBT, low-voltage CMOS devices havealso been demonstrated
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SiC: Technical Challenges
Materials: 75-100 mm bulk and epi wafers withlow defect density at a reasonable price
Oxide interface quality and reliability
Ion implantation processes: high temperatureimplantation and annealing
Sheet resistance and contact resistance for p-type
SiC doping Companion packaging technology
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Analysis of Switch Power Losses:A Simplified Case
SOFFdOFFS
SONdONS
OFFSONSSWITCHING
S
ONONCONDUCTION
SWITCHINGCONDUCTIONTOTAL
ftIVP
ftIVP
PPP
T
tIVP
PPP
)(0)(
)(0)(
)()(
0
2
1
2
1
=
=
+=
=
+=
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Interaction between the main switch andfreewheeling diode
Nonlinear waveforms
Time-varying PWM duty cycles Temperature-dependent device parameters
Analysis of Switch Power Losses:More Realistic Case
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Thermal Management
Switch power losses heat up the devices.
Maximum junction temperature is the limiting
factor on the power handling capability of devices.
Selection of appropriate device ratings and proper
thermal design are critical steps in power
electronics design.
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Electric Loads & Passive Components
Capacitors Inductors
Transformers
Lamps Solenoids, coils, and relays
Motors
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Capacitors
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Inductors
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Transformers
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Lamps
Conventional Halogen lamps are resistive loads. New automotive lighting technologies such as
High Intensity Discharge (HID) and LED need
special drive circuits. Challenge with 42V systems: A higher bus voltage
requires a higher filament resistance to maintain
the same power. This results in a thinner and/orlonger and less reliable filament. PWM can solve
the problem.
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Solenoids, coils, and Relays
Solenoids, coils, and relays are inductive loads in
nature. Voltage spikes occur when the load currents are
interrupted.
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Motors
AC DC
PMSynchronous Asynchronous
SRM
Stepper
Squirrel
Cage
3 -Induction
Hybrid
Field Winding
Wound
Rotor
DC field
winding
PM
Brushless DC
SeriesShunt
ISG
EV/HEV
regular
starters
ISG
EV/HEV
Lundell
alternator
small car
motors
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An Electromechanical System
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Power Electronic Converters
Overview
Steady state analysis
Pulse Width Modulation (PWM) concept
High-side, low-side, and H-bridge configurations AC/DC rectifiers
DC/DC converters
DC/AC inverters
Controls of power electronics
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Overview of Power Converters
Power electronic circuits move through different
topologies as power semiconductor switches open
and close
Time-domain circuit analysis
Circuits
ContainingSwitches
Output
FilterNetwork
Input
FilterNetwork
LoadSource
Power Flow
Power Converter
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Steady State Condition
In power electronic circuits, semiconductor
switches constantly change their ON or OFF
status.
A steady state condition is reached when the
circuit waveforms repeat with a time period T.
Time
T
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Average Power and RMS Current
Instantaneous power
Average power
RMS current
Power factor cos
1
)(1
)()()(
0
2
0
==
=
=
=
RMSRMS
av
T
RMS
T
av
VI
PPF
dtiT
I
dttpT
P
titvtp
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Steady State Analysis
Exploiting steady state conditions is extremely
useful in analyzing power electronic circuits
For capacitors:
average current = 0
For inductors:
average voltage = 0
0)(1
)()(
)(1
)()(
=>======= vtri:TA+ & TB- ON
vcontrol< vtri:TA- & TB+ ON
H-Bridge DC/DC
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Converter:Unipolar Switching
Vcontrol> vtri:TA+ ON
-vcontrol> vtri:TB+ ON
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DC/DC Converter Applications
Adjustable-speed DC motor drives:
electric engine fan, pinch-free power window,
smart windshield wiper, etc.
42/14V conversion
PWM lighting
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DC/AC Inverter
AC motor drives: EPS or drivetrain
Single-phase square-wave inverter
Single-phase PWM inverter
Three-phase PWM inverter
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Single-Phase (H-Bridge) Inverter
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Switch Control
Valid switch combinations are those that do not
short or open the load
Only four valid switch states for H-bridge
inverters:
- TA+ & TB- ON, TA- & TB+OFF => Va=Vdc- TA- & TB+ ON, TA+ & TB- OFF => Va=-Vdc- TA+ & TB+ ON, TA- & TB- OFF => Va=0
- TA- & TB- ON, TA+ & TB+OFF => Va=0
Square-Wave
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Square Wave
Switching
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PWM Switching (Bipolar)
When vcontrol>vtri,TA+ & TB- ON
When vcontrol
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When vcontrol>vtri,TA+ ON
When -vcontrol>vtri,TB+ ON
W Sw tc g
(Unipolar)
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Three-Phase Inverter
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PWM Switching ofThree-Phase
Inverter
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Control of Power Electronics
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Separation of Time Scales
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PWM Control
PWM is the main technique in power converters
Automotive Power Electronics:
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Case Studies
Fuel injector solenoid driver circuits
IGBT ignition coil driver circuits
Electric power steering systems
42V PowerNet Electric/Hybrid drivetrains
F l I j i S
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Fuel Injection System
F l I j t S l id D i Ci it
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Fuel Injector Solenoid Driver Circuit
F h li Di d f P t ti
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Freewheeling Diodes for Protection
Common
V +
Inductive Load
MCU or
CMOS IC
PWM Generator
Free Wheeling
Diode FWD
V + SUPPLY
Common
D l L l C t C t l
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Dual-Level Current Control
A large current passes
through the inductivesolenoid load which
quickly opens the valve
for fuel release.
A lower current is then
needed to maintain (or
hold) the fuel injectorvalve until completion.
Fast Recovery Solenoid Driver
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Circuits
The electromagnetic energy of an inductive load
sometimes needs to be cleared quickly. A higher voltage is needed to bring the load current
to zero faster.
V = L di/dt
V + SUPPLY
Common
V + SUPPLY
Common
Fast Recovery Solenoid Driver
Ci i (C )
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Circuits (Cont)
VDC 100-130
Current Sense
Direct In Combustion
Cylinder Fuel Injection
Solenoid
Switches:
Power Fet"s
IGBT's
1 per Cylinder
14 to 53 Volts
Boost
Converter
Hi-Side
Drive
Ignition Coil Driver Circuits
Di ib S
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Distributor Systems
Ignition Coil Driver Circuits
Di t ib t l S t
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Distributorless Systems
Ignition Coil Driver Circuits
C il Pl (COP) S t
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Coil-on-Plug (COP) Systems
IGBT Ignition Driver Circuit
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IGBT Ignition Driver Circuit
Primary voltage: 350-600V
Secondary voltage: 20-40KV
Inductive Switching
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Inductive Switching
Detailed Waveforms
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Detailed Waveforms
Electric Power Steering Systems
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Electric Power Steering Systems
Motor
Pump
Motor Controller
Sense
I sense
hydraulic cylinderValve
Hydraulic tubes
electricmotor
Motor Controller
Angle sense
Steering wheel
Torque sense
EHPS
Electro Hydraulic Power Steering
Brushless or Induction Motordrives pump
ECU controls motor driving the
hydraulic pump.
EPS, Electric Power Steering
Or Direct-Assist Power Steering
Electric motor provides assistance
ECU controls motor driving thesteering column
EHPS and EPS
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EHPS and EPS
GearBox
PowerStage
SteeringColumn
HydraulicPump
Current
Sense
SteeringWheel
Microcontroller
PressureSensor
WheelPosition
Angle / Torque
Motor
VehicleSpeed
PowerStage
SteeringColumn
CurrentSense
SteeringWheel
Microcontroller
WheelPosition
Angle / Torque
Motor
VehicleSpeed
GearBox
EHPS EPS
EHPS Power Electronic Circuit
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EHPS Power Electronic CircuitPM MOTOR, SINGLE POWER TRANSISTOR
LOW-SIDE PWM DC/DC DRIVE
Supply Voltage
Sense Input
PWM
Output
+ 12V
PM
Motor
Power
Stage
PUMP
GateDrive
com.
MCU
N-FET Drain Voltage
Sense Input
+ D
G
S
POWER
RELAY
Pressure
Sensor
RESET 5V REG
LVI
COP
+12 Ignition
Osc
Vehicle
Speed
Sensor
Diagnostic
Port
8 bit Core
A/D
PWM
SCI
FWD
N-FET
EPS Power Electronic Circuits
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EPS Power Electronic Circuits
Brushless DC or Induction
Motor Drive
Switched Reluctance
Motor Drive
42V PowerNet
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42V PowerNet
100
1,000
10,000
100,000
1920
1930
1940
1950
1960
1970
1980
1990
2000
2010
2020
2030
Year
w/ Propulsion
wo/ Propulsion
1.8 kW
15 kW
40 kWGrowth Rates:
1920-40 6%/yr
1940-70 2%/yr
1970-90 6%/yr
Projected 1990-2030:
w/o Proplsn. 5%/yr
w/ Proplsn. 8%/yr
1900s
6V Systems
1950s
12V Systems
1970s
12V Systems
5V Electronics
1960s
12/24V
Heavy Duty
Power
Requirement(W
atts)
42V Voltage
Specification0 9 1 1 1 4 .3 2 0Ve h i c l e B u s Vo l t a g e ( 1 4 V S u p p l y )
1 6
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Specification
0 5 1 4 1 8 2 2
M in . Op . V olt
N o m i n a l O p . V o l t
M a x . O p . V o l t
M in Ze n e r Cla m p V olt .
S e m i c o n d u c t o r Re q u i re m e n t s
0 5 4 2 5 2 5 8
M in . Op V olt
N o m i n a l O p . V o l t
M a x O p V o l t
M in Ze n e r Cla m p V olt
S e m i c o n d u c t o r Re q u i re m e n t s
Ve h i c l e B u s Vo l t a g e ( 4 2 V S u p p l y )
0 2 5 3 3 4 3 5 6
M in S t art V olt .
M in V olt . En g. OFF
M a x V o l t E n g . O N
M ax V olt C LD
5 2
0 9 2 0
M in S t art V olt .
M in . V olt En g. OFF
M a x V o l t E n g . O N
Ma x C l a m p Vo l t .
1 6
42V Electrical Architectures
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42V Electrical Architectures
ElectronicModule
Alt
Str.
B1
Mot.
B2
C1
C2
42V
14V
Electronic
ModuleC2
Alt.C1
B1
B2
42V
14V
Str.Mot
42V Integrated Starter Generator
(ISG)
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(ISG)
42V/14V DC/DC Converter
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PWM
Controller42V 14V
S1
S2
Control Input
Bi-directional conversion (42V 14V)
1-2KW output power
42V Distribution Circuits
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DC
DC
CS51022 14V
DC
DC
Low Power5V, 3.3V
DC
DC
CS5102214V
DC
DC
CS5102214V
Other 14V Loads
(including other lamps)
Right Lamps
Left Lamps
Type C Semiconductors
(ECU. Logic, Memory, etc.)
42V Loads42V
Battery
ISA
42V Multiplexing Network and
Smart Junction Box (SJB)
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J ( J )
Electric and Hybrid Drivetrains
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y
Bus voltages: 42-300V
Power ratings: 5-100KW
Motors: induction, BLDC, SRM
Power converters: IGBT or MOSFET PWM
inverters
Control design: P- or DSP-based vector control
Power Conversion
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Three-Phase PWM Inverter
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3 legs / 6 active switches
Fixed switching frequency
Variable switching duty cycle
Both frequency and amplitude of
phase voltages controllable
KEY: switching sequence of
active switches
Control of AC Motor Drives
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Control stator voltage
amplitude and frequency
Simple implementation
Acceptable steady statecharacteristics
Poor transient response
Poor transient efficiency
Control stator voltages and
currents represented by
vectors
Accurate control for bothsteady state and transient
operations
High efficiency
Complex implementation
(DSP and sensors)
Scalar Control (V/f ) Vector Control (Field Oriented )
Advanced Vector Control for AC
Motor Drives
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Emerging Issues in Automotive Power
Electronics
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Power losses and efficiency
Inverter power module reliability
Novel thermal management technology
Cost reduction with better power bus regulation
EMC concerns
42V or higher voltage electrical architectures
Power Losses and Conversion Efficiency
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Power losses of power switching devices, conversion
efficiency, and thermal management are the key designissues for electric drivetrains and other automotive
applications (e.g., EPS)
New circuit topologies: cascade or soft switching inverters
Selecting the right switching devices: a complex design
trade-off
Peak vs. normal power design dilemma (ratio as high as
10:1): load leveling approach
Reliability of Power Electronic ModulesA k l t t d ki l t i l i ti l i
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A key element toward making electric propulsion more practical is
the development of cost-effective, high-efficiency integrated power
electronic modules.
The reliability of these power modules will be of paramount
importance for the success of various EV/HEV concepts due to the
critical safety concern for drivers/passengers, stringent quality
assurance requirements of vehicles, and extremely harsh
underhood automotive environments.
In addition, automotive electric drivetrains, due to their wide
dynamic range of operation and diverse usage profiles, will likely
impose a more stringent reliability requirement on the power
modules than any other industrial motor control applications.
Reliability and Failure Mechanisms Elevated junction temperatures (150oC max)
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Elevated junction temperatures (150 C max)
Thermal-mechanical stress and fatigue: wire bond lift-off, solder
joint cracks, Si chip cracks, etc.
Vibration
Contamination
Defects
Si Chip Si Chip
Cu
Baseplate
Direct Bond Copper Substrate
Solder Joints
Wirebond Connector
Case
Research in Power Module Reliability
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Improving Understanding on Module Reliability Requirements
Developing Realistic Reliability Testing Standards and LifetimeProjection Models
Enhancing System Diagnostic Capability with Early Warning
Fault Detection (embedded diagnostics/prognostics for power
electronics)
Drive Cycle &
Usage
Analysis
Inverter
Module
Power Loss
Analysis
Inverter
Module
Thermal
Analysis
Inverter
Module
Stress
Analysis
Drive Cycle and Power Loss
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0 1000 2000 3000 4000 5000 6000 700040
60
80
100
120
140
160
180
200
220
240 ISG P owe r Los s Trace
Time (s)
PowerLoss(W)
0 1000 2000 3000 4000 5000 6000 70000
500
1000
1500
2000
2500
3000
Time (s )
RPM
CITYNEW Drive Cycle Speed Trace
Novel Thermal Management
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Removal of heat from power electronics is the limiting
factor for cost, compactness, and reliability. The disparity between the peak load capability and average
load operation of automotive power electronics severely
lowers the hardware utilization efficiency and sets a limit
on cost reduction and reliability enhancement.
Peak power load is typically several times higher than
average power load, but only lasts for a short period of
time ranging from a few tens of milliseconds to a fewseconds.
Phase Change Thermal Management Transitions between solid,
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liquid, and gaseous phases
typically involve large
amounts of energy comparedto the specific heat. For
example, one gram of water
absorbs merely 4.18 joules of
heat to increase its
temperature by 1o
C, butamazingly 2260 joules of heat
when vaporized even without
any change in temperature.
Phase change materials can be
used as passive heatmoderators in power
electronic packages.
Silicon
Case
Heat Sink
Conventional Power Electronics Module
Silicon Phase Change
Heat Moderator
Heat Sink
Proposed Power Electronics Module
Case
Time
J
unctionTemperature
Peak Load Average Load
Conventional
Power Module
Phase Change
Power Module
Improve Power Bus Voltage
Regulation to Reduce Cost ofAutomotive Power Electronics
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0 20 40 60 80 100 1200
0.5
1
1.5
2
2.5
3
3.5
4
Breakdown Voltage (Volts)
SpecificOn-Res
istance(mohm-cm2)
Theoretical limit of Silicon
Dis crete
P ower IC
15 20 25 30 35 40 45 50 55 60 65
1
1.5
2
2.5
3
DC VOLTGAE RATING (V)
NORMA
LIZEDCOST
Power MOSFET Ron vs Voltage Rating Capacitor Cost vs Voltage Rating
Automotive Power Systems
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Automotive
Po w er
Sy stems
Battery
Voltage
Nominal
Operating
Voltage
Maximum
Operating
Voltage
Maximum
Dynamic
Over-
voltage
Power
Electronics
Voltage
Rating
12V
Car/Light
Truck
12 V 14V 24V
(Jump
Start)
_ 60-40V
24V
Heavy
Truck
24 V 28V 34V _ 80-60V
42V
Po w e rNe t
36 V 42V 50V 58V
(Load
Dump)
100-75V
Transients in Automotive
Environments
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Time
Duration
Caus e Vo ltag e
Amplitude
Energy
Level
Frequency
o fOccurrence
200ms to
400ms
Load dump
(disconnection of
battery while at
high charging)
10J Infre que nt
Steady
State
Fa ile d voltage
regulator
18V _ Infre que nt
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NORMAL BUS VOLTAGE
TVS CLAMPING VOLTAGE
VOLTAGE
RATING
OF POWER
ELECTRONICS
6-24V 6-24V
4-40V
0-60V
24-27V
Existing Voltage
Rating
Proposed Voltage
Rating
NORMAL BUS VOLTAGE
TVS CLAMPING VOLTAGE
VOLTAGE
RATING
OF POWER
ELECTRONICS
10-34V 10-34V
4-60V
0-60V
34-37V
Existing Voltage
Rating
Proposed Voltage
Rating
Introduction of A New Class of
Transient Voltage Suppressors:MOSTVS
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Much less variations in clamping voltage than conventional Zener
diodes or MOVs over a wide range of current and temperature.
Proven power MOSFET technology
Provide cost benefits in 12V, 24V, 42V or higher voltage systems
BTB Poly DiodesD
S
Rg
G
Module 1 Module N
Central Suppressor Distributed Suppressor
DC Power Bus
Electromagnetic Compatibility
Concerns
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EMC compliance is a major challenge for automotivepower electronic systems
Large common-mode inverter currents due to couplingpaths to ground through the motor and housing
Large di/dtand dv/dt, while minimizing switching losses,
generate broadband radiated and conducted emissions. RF characteristics of power semiconductor
devices(especially bipolar types) are neither fullyinvestigated nor considered in the EMC consideration.
Conducted immunity concerns: load dump, negativetransients, etc.
Electrical/Electronic Architectures
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Electrical Architectures: Power
Generation and Distribution
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Active power management: multiple power sources, loads,
energy storage elements, multiplexing, etc. System stability may become a major concern.
Arc fault detection is critical for 42V or higher voltage
electrical distribution systems:
Distributed current sensor network and DSP to detect
arc fault signatures
Arc fault detection should be an integral part of
electrical architecture design rather than using add-onapproach
Summary
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Power electronics will become more pervasive in
automotive systems. Device and circuit technology advances need to be
made to meet performance, reliability, and cost
targets. Many critical technical challenges and barriers
need to be overcome.