automotive systems course (module 07) - charging systems for road vehicles

25 de novembro de 2016 | 1

Sistemas A

uto

mó

veis

Charging Systems

Mário Alves ([email protected])

mailto:[email protected]


Sistemas A

uto

mó

veis

Outline

• Charging System

• definition, components, trends, requirements

• Alternator

• operational characteristics, evolution, manufacturers, types

• Electromagnet inductor alternator

• main components + assembly, rotor, stator, brushes, slip rings, rectifier, voltage regulation

• Permanent magnet inductor alternator

• main differences, inner/outer inductor types, voltage regulation

• Cooling

• Future trends

• Glossary

• Recommended references


Sistemas A

uto

mó

veis

Charging System: definition

• Electric components and circuits that act as electrical power

source in a vehicle

• the term “charging system” is preferred in the mechanical/automotive

domain, against “power source” (used in the electrical engineering

domain), to distinguish from “engine/mechanical power”

• Combines two primary energy sources

• chemical energy (from the battery)

• supplies electrical energy when engine is off, cranking and

whenever the alternator does not cope with the load

• mechanical energy (from the engine and from the vehicle’s

kinetic energy, in electric/hybrid vehicles)

• enables to generate electrical energy when the engine is

running, through a generator (dynamo or alternator)


Sistemas A

uto

mó

veis

Charging System: basic block diagram

https://autoelectricalsystems.wordpress.com/2015/09/19/electric-power-system-of-a-vehicle/














Sistemas A

uto

mó

veis

Charging System: main components

• Main components (typical charging system)

• battery assembly (may feature more than one battery)

• alternator assembly (alternator, voltage regulator, rectifier)

• electrical wiring, switches, relays, connectors/connection boxes

• fuses and circuit breakers

• alternator belt and indicator light

http://www.autozone.com/

https://www.2carpros.com/questions/buick-regal-1999-buick-regal-serpentine-belt-replacement




















Sistemas A

uto

mó

veis

Charging System: technology and market trends

• All figures are growing!

• > market (5.4% growth/year)

• > power demand (100 W/year)

• > cost weight % (of car cost)

http://ecomodder.com/forum/showthread.php/list-typical-electrical-loads-modern-car-7196.html

http://www.marketsandmarkets.com/Market-Reports/automotive-starter-motor-alternator-market-120529968.html htt

p:/

/ww

w.e

etim

es.c

om

/docu

men

t.as

p?doc_

id

=1272772&

pag

e_num

ber

=2














http://www.marketsandmarkets.com/Market-Reports/automotive-starter-motor-alternator-market-120529968.html














http://www.eetimes.com/document.asp?doc_id=1272772&page_number=2




Sistemas A

uto

mó

veis

Charging System: requirements

• Main requirements

• cope with the electrical power demand from all electrical/electronic

systems in the vehicle, in all operating conditions (RPM,

temperature, different number of electrical loads)

• mind the different types of electrical loads:

• guarantee a stabilized voltage, in all operating conditions

• reliable, light-weight, silent, low-cost

• energy-efficient (SOTA 80%)

• malfunction indicator

http://www.nairaland.com/2215208/photos-how-understand-dashboard-warning












Sistemas A

uto

mó

veis


• Interplay between the two power sources













Sistemas A

uto

mó

veis


• Load types according to duty-cycle

• Continuous-operation electric loads

• always on

• e.g. fuel pump, fuel injectors, ignition, ECUs

• Prolonged-operation electric loads

• turned on for long periods

• e.g. head/tail lights, Multimedia, HVAC, radiator fan

• Sporadic-operation electric loads

• Turned on for short periods

• e.g. starter motor, power windows/roof/locks, wipers/washers, horn,

windows/mirrors defoggers, ABS/TCS/ESP, pre-heating systems

• These statistical properties must be accounted for

• dimensioning the battery/alternator (based on average power)

http://www.eetimes.com/document.asp?doc_id=1272772


















Sistemas A

uto

mó

veis


• Electric loads

• total power for mid-size car 3.5 kW

• different duty-cycle properties

(continuous, prolonged and sporadic)



















Sistemas A

uto

mó

veis

Charging System: battery

• Typical battery internal resistance characteristic:

https://autoelectricalsystems.wordpress.com/page/6/

Engine

cranking

Ri = U/ I = 4/220 ≈ 18 mΩ


Sistemas A

uto

mó

veis

Alternator: operational characteristics

• Typical current vs RPM output of a car alternator

• current/power grows with RPM (overdamped behavior)

• typically, alternator rotates 2-4 faster than engine

• current/power drops with alternator temperature increase

http://www.pirate4x4.com/tech/billavista/Wiring/Part2/

http://www.agcoauto.com/content/news/p2_articleid/348






Sistemas A

uto

mó

veis


• Typical voltage vs current output of a car alternator

• voltage drops with current increase (abruptly above nominal current)

http://www.aturnofthenut.com/2016/02/11/alternators-with-multiple-battery-banks/












Sistemas A

uto

mó

veis


• Typical power efficiency vs RPM

• efficiency decreases with RPM increase

http://www.intechopen.com/books/new-advances-in-vehicular-technology-and-automotive-

engineering/power-electronic-solutions-to-improve-the-performance-of-lundell-automotive-alternators

http://www.intechopen.com/books/new-advances-in-vehicular-technology-and-automotive-engineering/power-electronic-solutions-to-improve-the-performance-of-lundell-automotive-alternators





































Sistemas A

uto

mó

veis


• Power efficiency is affected by

• Mechanical losses

• brush and bearing friction

• claw pole rotor and cooling fan

• Electrical losses

• stator and rotor wirings

• regulator and rectifier

• Magnetic losses

• stator and rotor windings

http://www.intechopen.com/books/new-advances-in-vehicular-technology-and-automotive-

engineering/power-electronic-solutions-to-improve-the-performance-of-lundell-automotive-alternators

RPM 1800 6000

Mechanical losses 2% 6%

Excitation losses (rotor) 7% 3%

Magnetic losses (stator) 21% 20%

Copper losses (stator) 49% 57%

power rectifier losses 21% 14%






































Sistemas A

uto

mó

veis

Alternator: evolution

• From the dynamo to SOTA alternators

• more power, efficiency and reliability

• less noise and vibration

http://www.autoserviceprofessional.com/article/94748/alternator-decouplers-servicing-these-vibration-

reducing-pulleys

http://www.autoserviceprofessional.com/article/94748/alternator-decouplers-servicing-these-vibration-reducing-pulleys















Sistemas A

uto

mó

veis

Alternator: manufacturers

• Car alternator manufacturers

• Denso

• Bosch

• Valeo

• Remy

• Hella

• ISKRA

• Mando

• Mitsubishi

• Hitachi

• Magneti Marelli

• …

https://www.newswire.com/press-release/car-alternator-market-global-technical-data-and-growth-2020






















Sistemas A

uto

mó

veis

Alternator: types

• Alternators can be mainly classified according to the type of

magnetic excitation/inductor (in the rotor)

• permanent magnets (brushless alternator) – left

• electromagnets (field coil) – right

http://www.windbluepower.com/Permanent_Magnet_Alternator_Rotor_Fits_Delco_10SI_p/pma-rot.htm

http://mechanics.stackexchange.com/questions/25635/what-are-slip-rings-with-respect-to-a-cars-alternator


























Sistemas A

uto

mó

veis

Alternator: electromagnet inductor type

• Main components and assembly

http://de.bosch-

automotive.com/en/parts_and_accessories/motor_and_sytems/starters_alternators_1/alternators_for_cars_1/starters_alternators_alternators

http://de.bosch-automotive.com/en/parts_and_accessories/motor_and_sytems/starters_alternators_1/alternators_for_cars_1/starters_alternators_alternators







Sistemas A

uto

mó

veis


• Components and assembly

1. Drive pulley

2. Rotor

3. Slip ring

4. Rotor windings

5. Stator + windings

6. Rectifier

7. Output connector

8. Field diodes

9. Voltage regulator

10. Brush assembly

11. Fan


11




Sistemas A

uto

mó

veis


• Basic circuit (Y stator, 9 diodes, integrated regulator)

https://www.alternatorparts.com/understanding-alternators.html

This block

does not exist

in brushless

alternators






Sistemas A

uto

mó

veis


• Rotor (inductor)

• regulator feeds DC current to field coil through

brushes-slip rings contact

• typically 6 or 8 N/S pole pairs (12 or 16 poles)


6 pole pairs

8 pole pairs




Sistemas A

uto

mó

veis



• alternating N/S poles in polar “fingers/claws”

• induce EMF in the stator windings

http://autosystempro.com/tag/generators/




Sistemas A

uto

mó

veis



• Slip rings in more compact alternators (e.g. motorcycles) can

also be perpendicular to the alternator shaft

http://www.ebay.com/bhp/cb650-rotor






Sistemas A

uto

mó

veis


• Stator + rotor layout

• EMF must be additive, in all coils of a phase winding

http://www.pangolin.co.nz/node/16

…




Sistemas A

uto

mó

veis


• Stator wiring configurations

• always 3-phase, Y (wye) or (delta) wiring

• usually 6 or 12 coils per phase (18 or 36 coils total)

http://www.instructables.com/id/How-To-Rewind-an-Alternator/step3/Star-or-Delta-windings/





















Sistemas A

uto

mó

veis


• Brushes + slip rings

• each brush connects to one slip ring

• one brush is + and the other is –

• the slip rings are electrically connected to the field coil terminals

• regulator controls excitation through ON/OFF control

http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/753046-alternator-question.html

http://www.allaboutcircuits.com/textbook/experiments/chpt-4/automotive-alternator/
























Sistemas A

uto

mó

veis


• Rectifier (diode) bridge

• 3-phase bridge based on passive elements (diodes)

• brushless alternator has a different rectifier principle!

• Typical rectifier assembly designs and mounting


http://www.asia.ru/ru/ProductInfo/891739.html





Sistemas A

uto

mó

veis


• Diode types

• “Phase” diodes – full wave rectification of the 3 phases

• 6 power diodes (minimum configuration)

• 3 + and 3 – power diodes (2 diodes per phase)

• for electrical power-hungry vehicles, each phase has 4 diodes

• “Neutral” diodes – full-wave rectification of the neutral

• 2 diodes connected to the neutral point (only for Y wiring)

• induced third harmonic voltage increases output current/power

at high RPMs (> 2000-3000) 5-10% extra output power

• can be used for B+ or to feed the regulator/field coil

• “Field” diodes (AKA as excitation diodes or diode trio)

• 3 diodes (connected to the phases) feed the field coil

• half-wave rectification (it is sufficient for the field coil)

Bosch Automotive Electrics and Automotive Electronics: Systems and Components, Networking and Hybrid Drive, Edition 5, 2013

http://youronlinemechanic.com/alternator-with-neutral-point-voltage/












Sistemas A

uto

mó

veis


• Bridge configurations (combinations of the previous)

• 6 power diodes (minimum configuration)

• 3 + and 3 – power diodes (2 per phase)

• 8 power diodes

• 6 power diodes

• 2 diodes for the neutral

• 9 diodes

• 6 power diodes

• 3 field diodes

• 11 diodes

• 8 power diodes

• 3 field diodes

• 17 diodes

• 12 power diodes (4 per phase)

• 2 diodes for neutral

• 3 field diodes

…













Sistemas A

uto

mó

veis


• 6-diodes bridge

http://forums.off-road.com/jeep-short-wheelbase/276087-alternator-based-board-welders-set-me-straight.html

…
























Sistemas A

uto

mó

veis


• 8-diodes bridge

http://www.wiringdiagrams21.com/2013/03/04/suzuki-4x4-sj413-alternator-and-charging-system-circuit/

http://www.google.com/patents/US6828703




















Sistemas A

uto

mó

veis


• 9-diodes bridge







Sistemas A

uto

mó

veis


• 11-diodes bridge

http://xwebforums.org/showthread.php?t=16065&page=2




Sistemas A

uto

mó

veis


• 17-diodes bridge (for high power requirements)

Bosch Automotive Electrics and Automotive Electronics: Systems and Components,

Networking and Hybrid Drive, 5th Edition, 2013


Sistemas A

uto

mó

veis


• Voltage Regulator

• Guarantees a steady DC voltage output regardless of the RPM

• “senses” output voltage

• should be around 14.5 V

• controls the excitation of the alternator

• field coil current (ON/OFF)

• ON EMF induction

• OFF no induction

https://en.wikipedia.org/wiki/Voltage_regulator

…

Regulator acts as

an on/off switch

Switching

duty-cycle

influences

output voltage




Sistemas A

uto

mó

veis


• Voltage Regulator

• switching can be on the positive or negative side of the field coil





Sistemas A

uto

mó

veis


• Voltage Regulator operating principle

• Electromechanical (until the 60s)

• based on electromechanical relays

• Electronic (60s to 90s)

• based on discrete or integrated electronic circuits

• ECU-controlled (90s to date)

• sensing, computation, actuation

• optimizes alternator (regulator) output voltage and

alternator torque, depending on several operating conditions

• protects battery and optimizes fuel consumption/exhaust

gas emissions


…




Sistemas A

uto

mó

veis


• Mechanical Regulator

• basic operating principle


…




Sistemas A

uto

mó

veis


• Electronic Regulator (MOSFET-based)

http://chemelec.com/Projects/Alternator/Alternator-Reg.htm

…






Sistemas A

uto

mó

veis


• Electronic Regulator (bipolar transistor-based)


…






Sistemas A

uto

mó

veis


• Electronic Regulator (IC-based)

• control section, power stage, fault

diagnosis (controls warning lamp) and

protection against short circuits.

http://img.radiokot.ru/files/104594/medium/pr2p35jk0.JPG

http://circuitswiring.com/l9407f-car-alternator-voltage-regulator-datasheet/















Sistemas A

uto

mó

veis




• ECU-controlled regulator (aka smart charging)

• controls changing rate based on electrical requirements,

battery/ambient temperature, and several other inputs

• reduces fuel consumption (reducing alternator load on ICE)

• optimizes & protects the battery

Powertrain Control

Module (engine ECU)






Sistemas A

uto

mó

veis


http://www.embedded.com/design/real-time-and-performance/4006472/Designing-

a-microcontroller-driven-alternator-voltage-regulator

• ECU-controlled regulator (thermal compensation)

• warm batteries are more efficiently charged with low voltage

and cold batteries with higher voltage

• ECU adapts charge voltage depending on battery temperature

• battery temperature estimated by intake air + water temperatures

• battery charging is optimized through real-time adjustment of

the alternator output voltage

http://www.embedded.com/design/real-time-and-performance/4006472/Designing-a-microcontroller-driven-alternator-voltage-regulator





















Sistemas A

uto

mó

veis


http://www.hella.com/startersalternators/assets/media/g06_ti_en_electronics_ford_smart_charge_system.pdf

• ECU-controlled regulator (alternator switch-off and ISC)

• Alternator switch-off when cranking the engine

• when the engine is started, the alternator is deactivated by

the PCM to reduce the engine drag torque

• the alternator is only switched on to the required value by

the PCM after the engine has been started up

• Engine idle speed control (ISC), depending on electrical load

demand and system voltage

• the PCM can increase the charge current by changing the

pulse-width modulated signal to the alternator

• when the electrical load (in idling) is very high

• when the vehicle electric system voltage is very low

(e.g. low battery charge)




Sistemas A

uto

mó

veis



• ECU-controlled regulator (consumers switch on/off)

• consumers are activated or deactivated in the event of

overvoltage or undervoltage (depending on electrical system

voltage variations), e.g. :

• air conditioning system

• heated windscreen

• heated rear window




Sistemas A

uto

mó

veis


http://www.automotive-eetimes.com/content/reduce-vehicle-power-consumption-and-

increase-efficiency-start-charging-system/page/0/1

• ECU-controlled regulator (Freescale)

• charging system ↔ ECU comm via LIN (control & diagnostic)

• Mechanical, Electrical, Thermal, Comm. Fault detection

http://www.automotive-eetimes.com/content/reduce-vehicle-power-consumption-and-increase-efficiency-start-charging-system/page/0/1























Sistemas A

uto

mó

veis


http://www.automotive-eetimes.com/content/reduce-vehicle-power-consumption-and-

increase-efficiency-start-charging-system/page/0/1

• ECU-controlled Regulator (EXAMPLE 2)

• …
























Sistemas A

uto

mó

veis

Alternator: permanent magnet inductor type

• Differences to electromagnet inductor alternators

• inductor (rotor) is made of permanent magnets

• does not have a field coil, brushes nor slip rings

• thus, voltage regulation cannot be performed in the same way

• because there is no control over the inductor magnetic field

• voltage regulation is performed by controlling the power output

• via a silicon controlled rectifier (SCR)

• Types

• Inner inductor/rotor

• outer inductor/rotor

http://www.five-gallon-bucket-hydroelectric.org/the-new-toyota-alternator-pma-for-the-generator/

…
























Sistemas A

uto

mó

veis


• Inner inductor permanent magnet alternator

• rotor rotates inside the stator

https://www.comsol.com/blogs/simulating-permanent-

magnet-generators/

https://www.comsol.com/blogs/simulating-permanent-magnet-generators/









Sistemas A

uto

mó

veis



• stator, rotor and regulator (left) and full assembly (right)

http://roadandrace.com.au/alternator_conversions.htm

http://cybermotorcycle.com/archives/willyg/index.html






Sistemas A

uto

mó

veis



• alternator mounted in a motorcycle

http://ebw.co.in/tag/adventure/




Sistemas A

uto

mó

veis


• Outer inductor permanent magnet alternator

• rotor outside the stator, incorporated in the flywheel

• magnets are located radially in the flywheel (made of steel)

• Advantages:

• the magnetic properties of the steel enhance the magnetic

field and increase coil current;

• magnetic attraction to the steel and centrifugal force help to

keep the magnets in position

• the weight of the magnets increase the flywheel weight

(inertial mass)





Sistemas A

uto

mó

veis



• rotor outside the stator, incorporated in the flywheel

• magnets are located radially in the flywheel (made of steel)

http://www.bikesandtravels.com/biker.aspx?ride=730

Flywheel Stator




Sistemas A

uto

mó

veis



• Advantages:

• the magnetic properties of the steel enhance the magnetic

field and increase coil current;

• magnetic attraction to the steel and centrifugal force help to

keep the magnets in position

• the weight of the magnets increase the flywheel weight

(inertial mass)





Sistemas A

uto

mó

veis



• Rotor mounted with flywheel gear (left)

• Stator mounted in engine case (right)

http://www.homemodelenginemachinist.com/showthread.php?t=14129




Sistemas A

uto

mó

veis


• Voltage Regulation

• shunt-type: short-circuits output current to ground

• series-type: output current is switched ON/OFF

http://www.radio-electronics.com/info/power-management/linear-power-supply-psu/series-voltage-regulator-theory-circuit.php

Shunt-type Series-type

http://www.radio-electronics.com/info/power-management/linear-power-supply-psu/shunt-voltage-regulator-theory-circuit.php










































Sistemas A

uto

mó

veis


• Voltage Regulation – shunt-type

• short-circuits output current to ground, to regulate voltage

Single phase

Three phase

http://racetechelectric.com/ft-751-voltage-regulators.html









Sistemas A

uto

mó

veis



• shunts performed by thyristors (gate controlled by a Zener)

http://www.microchip.com/forums/m350762.aspx




Sistemas A

uto

mó

veis



• another configuration

http://mastercircuits.blogspot.pt/2010/05/motorcycle-voltage-regulator.html








Sistemas A

uto

mó

veis



• shunts performed by thyristors (gate controlled by IC)

http://www.eevblog.com/forum/projects/car-alternators-vs-motorcycle-alternators/












Sistemas A

uto

mó

veis



• for a single phase alternator

http://mastercircuits.blogspot.pt/2010/11/single-phase-voltage-regulator.html










Sistemas A

uto

mó

veis


• Voltage Regulation – series-type

• output current is switched ON/OFF

• basic design:

http://www.circuitstoday.com/voltage-regulators






Sistemas A

uto

mó

veis


• Voltage Regulation – series-type

• real implementation:

http://mastercircuits.blogspot.pt/2013/09/3-phase-voltage-regulator-series-type.html

Generator

+ rectifier

Electronic

relay

Voltage sensing and

relay controller














Sistemas A

uto

mó

veis


• Voltage Regulation – fully-controlled rectification

• não encontrei nada aplicado à rectificação/regulação de

alternadores de ímanes permanentes com pontes rectificadoras

controladas (transistores, MOSFETs, tiristores)

http://i444.photobucket.com/albums/qq167/rjdoles/regulatorschematicdiagram.jpg

http://www.electrosport.com/technical-resources/technical-articles/how-motorcycle-charging-system-works


















Sistemas A

uto

mó

veis

Alternator: cooling

• Cooling

• air-cooled

• water-cooled

• oil-cooled

http://www.electronics-cooling.com/2002/05/thermal-design-challenges-in-automotive-alternator-power-electronics/

http://www.delcoremy.com/alternators/find-by-model-family/50dn-plus/

http://www.4-wheeling-in-western-australia.com/toyota-70-series.html

Oil-cooled (450 A brushless)

Air-cooled

Water-cooled












































Sistemas A

uto

mó

veis

Technology trends

• Overrunning Alternator Decoupler (OADs) pulley • helps "synchronize" the belt drive system for improved engine

efficiency, reduced noise and vibration and increased lifetime

• when RPM increases, the alternator's inertia creates resistance against the belt (alternator typically rotates 3x faster than engine)

• these factors often cause "rope-tow effect" in which belt and alternator speeds are out of phase; belt tensioners can absorb some of the resulting vibration, but the belt is affected by these forces

• an OAD pulley has an internal spring and clutch system that absorbs the force associated with belt accelerations and tension reversals and permits the alternator to "free-wheel" or "overrun" when the belt suddenly decelerates.

http://www.decouplerpulley.com/

https://youtu.be/jKMf-_Yl-AI










Sistemas A

uto

mó

veis

Technology trends

• Intelligent Alternator Control with regenerative braking

• generates electric power during

• overrun (drive phases in which the engine is not required to deliver

drive power)

• Braking (while the driver is applying the brakes)

• battery is charged to only about 80% of its capacity as long as the engine is

propelling the car

• battery charge exceeding the 80% threshold is generated only in overrun and

braking

• Advantages

• less fuel consumption (≈ 3%)

• more available (engine) power during acceleration (alternator is

disconnected whenever the engine is propelling the car)

http://www.greencarcongress.com/2006/09/bmw_introduces_.html




Sistemas A

uto

mó

veis

Glossary (English/Portuguese)

• …


Sistemas A

uto

mó

veis

Recommended references

• http://www.circuitstoday.com/voltage-regulators





automotive systems course (module 07) - charging systems for road vehicles

Engineering