Advance Engineering of Electrical and Autonomous Vehicles.pdf

Basics Advance Engineering of Electrical and Autonomous Vehicles

1. Advance Engineering of Electrical
and Autonomous Vehicles
Aditya Bharat Patil
M.Tech Automotive (ARAI-VIT Vellore)
B.E. Mechanical (MAE, Alandi, Pune)

2. Contents
•Electric and Hybrid Electric Vehicles
•Energy Storage Devices
•Energy Generation Devices
•Electric Motor

3. Battery Electric Vehicle

4. Battery Electric Vehicle
•In BEV, the total electricity is provided by the battery, there is no fuel tank for the storage of fuel, so BEV is
also called “pure electric vehicles”.
• It consists of a large rechargeable battery that doesn't release harmful toxic gas to the environment, but,
consumers suspect that it creates much pollution during the generation of electricity, manufacturing of
batteries and discarded battery dumping.
•The battery is charged from the grid power or any external energy source using a charging plug. Charging of
BEVs takes an average of 6 to 8 h for charging with a slow charges and 20 to 40 min with a fast charger,
leading to a mismatch with gasoline refueling time in internal combustion engine vehicle (ICEV).
•The performance of BEV is totally dependent on the battery capacity and its thermal management system.
Battery temperature plays a crucial role in governing the performance of the battery and the lifespan.
•In BEV electrical energy is converted to mechanical energy with minimum conversion losses. BEV is suitable
for short-distance and stop and run conditions. It ranges from 100 to 400 km, depending on the type of
battery installed.
•Vehicle charging time varies with the capacity of the battery, charging scheme, and series/parallel
connection used.
•For increasing the distance covered and capabilities we redirect to theupgraded version of HEV, PHEV, and
others.

5. Hybrid Electric Vehicle
•Hybrid means a merger of multiple types of technology, as in HEV there are two or more types of energy and
power sources to drive the vehicle.
•Energy sources such as a flywheel, battery or regenerative braking, and power sources such as battery bank,
fuel-cell (FC), ultra-capacitor (UC), or internal combustion engine (ICE).
•Researcher designed and constructed the FC/UC hybrid power source and found that 96.2% power
efficiency, provides a maximum speed of 158 km/h, and covers up to 435 km with a weight of 1880 kg.
•Proper energy management strategies and optimization lead to long mileage, reduction in emissions and
fuel consumption
•The benefit of HEV is that when the primary fuel (diesel, gasoline) storage tank gets void while driving the
ICE then the secondary source will work as a backup system to the driveline with its maximum range.
•Depending on the types of energy sources applied to the driveline HEV is further classified in to three
categories such as:
1.Series Hybrid
2.Parallel Hybrid
3.Dual Hybrid

6. Series Hybrid Electric Vehicle

7. Series Hybrid Electric Vehicle
•In series HEV, the electric motor, and the IEC directly power the driveline and it is used to charge the battery
and provide power directly to run the motor as shown in figure above.
•In this combination electric motor is the only source to provide traction power to drive the vehicle.
•These vehicles have large battery backup with small ICE and large electric motor, need a control algorithm to
maximize the driveline efficiency and minimize the losses.
•In this system, there is no mechanical link of ICE to the gearbox, which allows the ICE to work at maximum
efficiency.
•The major drawback is the multiple conversion stages involved in between the ICE and gearbox, which
reduces the overall efficiency and increase the cost of the battery and its components
•Chevrolet Volt was primarily operated as a series HEV.

8. Parallel Hybrid Electric Vehicle

9. •In parallel HEV, the driveline is parallelly connected to both the electric motor and IEC to provide the traction
power as shown in figure above.
•ICE works as a primary source of driveline and the electric motor work as a support to escalate the traction
power with a control strategy to effectively improve the fuel consumption.
•The advantage of this system is that it requires a small battery backup which decreases the overall
•cost, and that the battery is charged by regenerative braking
•and while in propulsion mode.
•A recent study, concluded that there is an increment of 68% in the fuel economy, the emission is decreased
by 40%, and there is an improvement of 12% in engine efficiency on real-world driving cycle.
•Honda Civic, General Motors Parallel Hybrid Truck are some examples of parallel HEV.
Parallel Hybrid Electric Vehicle

10. Dual Mode Hybrid Electric Vehicle

11. •Dual-mode HEV is also known as dual mode HEV or series parallel EV or power-split HEV, due to the
integration of series and parallel hybrids. The driveline architecture of dual-mode HEV is shown in figure
above.
•It is usually composed of two powertrain configurations, one consists of ICE and generator connected using a
gear assembly and another of the electrical drive system which consists of an electric motor, battery, and
generator Due to which it is known as power-split transmission because it can provide a wide range of
vehicle velocity with optimal engine speed operation.
•The main advantage of this system is that it can operate in both series and parallel modes. Toyota Prius is an
example of a power-split HEV.
•Dual-mode HEV is the most complicated and costly system for real-time application.
•Therefore, parallel HEV is more popular than all other configurations of HEV, even though HEV is 8e9 times
costlier than BEV and it can't be charged at the charging stations or homes via plugging.
Dual Mode Hybrid Electric Vehicle

12. Plug-In HEV

13. •Plug-in HEV can run on both battery and gasoline. These batteries can be charged at a charging station or at
home using an ordinary plug or by a regenerative braking system.
•They don't release any tailpipe emissions while running on battery but they release them while generating
electricity at power plant.
•PHEV is mostly run on electricity, used for short distances during the week. Only longer trips use gasoline
power when the battery power is exhausted. Plug-in HEV driveline architecture is shown in figure above.
•PHEV can cover a good distance range but it has certain disadvantages such as
•1) higher initial cost than BEV,
•2) not eco-friendly as it produces emission at generation ends.
•Because of these reasons, BEV is gaining more popularity than PHEV.
•To overcome all these problems researchers have been focusing on more efficient batteries and analyzing
•how their packaging, thermal analysis, testing and ranging, charging time, size and weight can be improved
to make it more efficient.
•Mitsubishi Outlander, BYD Tang, BYD Qin are the top-selling PHEVs in 2018.
Plug-In HEV

14. Fuel Cell Electric Vehicle
•Fuel cell electric vehicle (FCEV) driveline architecture is similar to BEV but in the place of a battery, a fuel
cell (FC) is inserted and uses hydrogen as a transport fuel.
• Fuel cell acts as an electricity generator that powers the electric motor for traction purposes. Fuel cells
are comparatively more efficient than traditional ICE and make it more fuel economical.
•Proton exchange membrane (PEM) fuel cell is the most widely used fuel cell because of its zero emissions,
quiet operation, high power density and flexible operating range .
•In FCEV the tank to wheel efficiency is more than 48% while for ICE it ranges from 25% to 35%.
•The main drawback of FCEV is the complex storage technology and high-end cost of setup.
•Toyota Mirai II, Hyundai Nexo, Riversimple Rasa are some examples of FCEV.

15. Comparison

16. Energy storage and generation systems
•Energy storage devices:
1.Battery
2.Super-capacitor
3.Flywheel
4.Hydrogen storage

•Energy generation systems:
1.Fuel cell
2.Photovoltaic cell system
3.Regenerative braking system

17. Energy storage devices

18. Energy storage devices: Battery
•Battery is the most widely used device in almost any of the existing technologies (mobile, homes, towers,
backup systems, etc.), as it directly converts the chemical energy into electrical energy and vice versa in
rechargeable battery.
•Today, only some specific type of batteries are used in EV applications such as the lead-acid battery, NiMH
battery, and Lithium-ion battery.
•Lead-acid is the most broadly used type of battery in internal combustion based vehicular applications. Each
cell is immersed in a diluted electrolytic solution of (sulphuric acid H2SO4).
•Every cell has two positive and negative electrodes made up of lead dioxide (PbO2) and sponge lead (Pb)
respectively.

19. •Nickel metal hydride (NiMH) are more popular for hybrid vehicles as they are capable of high discharge
capacity and safety.
•Nickel-cadmium battery was the widely used battery, before the development of the NiMH battery, the main
issue with this battery is that its quality degrade due to shallow charging cycles .
•In nickel-metal hydride (NiMH) battery 30 wt% of KOH aqueous solution is used as an alkaline electrolyte.
•A positive electrode is composed of Ni(OH)2/NiOOH and a negative electrode is composed of metal hydrides
such as nickel, vanadium, and titanium metals.
•NiMH battery have almost double the energy density as compared to the lead-acid battery.
•Lithium-ion (Li-ion) battery has high energy and power densities among all other batteries and has a long
service life, low self-discharge rate, and the adequate safety requirement.
•Li-ion battery has five distinct layers: the positive current collector, the positive electrode (cathode),
separator, negative current collector, and a negative electrode (anode).
•Cathode are generally metal oxide with layered structure of LiCoO2/LCO, LiMn2O4, LiFePO4/LPF, and anodes
are made up of graphite or a metal oxide. The electrolyte can be liquid, solid, or polymer.
Energy storage devices: Battery

20. Energy storage devices: Super-capacitor
•Super-capacitor (SC) is also known as an ultra-capacitor (UC) or electrochemical capacitor (EC). They can
release large amounts of power and can be recharged in a short period of time.
•Battery work on the principle of conversion of electrical energy from chemical energy but due to the electric
double layer (EDL) effect SC can directly accumulate the electrical energy.
•SC can be charged and discharged at a very high specific current value (A/kg), 100 times more than that of
•battery, without damaging the unit.
•Carbon-based conduction polymer and transition metals are used for electrode material as they play a vital
role in enhancing the performance of SC.
•Biomass-derived activated carbon electrode is an alternative that consists of a high specific area and high
electrical conductivity
•Classification of SC on the basis of material used for the construction of electrodes are shown in figure on
next slide.

21. Energy storage devices: Super-capacitor
•Electrical double-layer capacitance (EDLC) has gained more popularity among all other types as, high energy
density, maintenance-free life-long operation, fast charge/discharge rate, and environment-friendly materials.
•Each electrode is made using a porous from of activated carbon material, which gives high energy density with an
equivalent area of 2000 m2/cm3.
•The rated cell voltage is 2.6 V. SC can improve the expected life cycle of the battery, with a value of maximum
effectiveness of 52%, for driving pattern without negative slopes.

22. Energy storage devices: Flywheel
•Flywheel stores the kinetic energy (KE) in a high speed rotational metallic or alloy disc, attached to the
central shaft of the electrical machines. This stored energy is restored to the system when necessary.
•Flywheels have a long life cycle, high power density, very little environmental impact, long operational life
and can store megajoules (MJ) of energy when configured in banks with high cycle efficiency (85%).. It stores
energy on the rotating mass principle.
•The whole flywheel energy storage system (FESS) consists of an electrical machine, bi-directional converter,
bearing, DC link capacitor, and a massive disk.
•Its high efficiency (90% to 95%) is its major advantage in all ESS.
•In HEV and EV, the flywheel is used to store the energy, and used when harsh acceleration is required to
climb steep uphill roads .
•FESS rank better than batteries as they serve longer life cycles, high charge and discharge rate cycles, high
power density, and higher efficiency.
•The Porsche 918R hybrid concept sports car with a flywheel storage system was announced in the 2010
Detroit Motor show.

23. •Hydrogen can be produced on the vehicle, stored directly in the tank and utilized by the fuel cell, by
reforming the methanol or hydrocarbons fuels extracted from diesel and gasoline .
•Hydrogen storage can be realized via different methods: gas storage, liquid storage, solid storage, metal
hydride storage, carbon nanotubes, and metal-organic framework.
•The storage of gaseous form of hydrogen is being used widely in technologies nowadays.
•Gaseous form of storage is done at 700 bar pressure while storage in liquid form requires cooling at a very
low temperature of 5K (268.15 C).
•On the other hand, storage in solid form requires absorption in carrier material to form hydride or
•surface absorption.
•The reaction between hydrogen and metal alloy release heat (exothermic reaction) from which energy is
generated.
•Heat transfer management is the major issue that arise during the hydrogen loading and unloading times to
and from the storage tank.
•Hydrogen can be generated from the economizer at the charging station and EV can fill from the respective
stations.
Energy storage devices: Hydrogen storage

24. Energy generation systems

25. Energy generation systems: Fuel cell
•A Fuel cell is an electrochemical device that directly converts the fuel from
an external source into electricity through chemical reaction on the
electrode surfaces submerged in the electrolyte for the transportation of
ions.
•Fuel cells can initiate its working without any intermediate step of heat
generation as were used in other ICE and other heat engines.
•Fuel cell operates at the highest efficiency ranges from 40% to 85% in
comparison to all other power generation systems.
•At the anode,hydrogen is oxidized into protons and electrons whereas at
the cathode oxygen is reduced to oxide species and reacts to form water as
residue output.

26. Energy generation systems: Photovoltaic cell
system
•Electrification of vehicles gives an opportunity to switch over to renewable energy sources like photovoltaic
(PV) for charging or providing energy .
•There are certain benefits of charging EV with a solar-powered system.
•First, the EV charging profile match the generation profile of the PV system.
•Secondly, the solar PV system can be installed at a very remote location, and can be installed near the
charging station.
•Third, the solar PV system can be equipped with the grid system with the help of inverters to improve the
load profile, reactive power demand and thus keep the power quality of undisturbed form large and
unevenly distributed charging demands.

27. Energy generation systems: Regenerative
braking system
•Regenerative braking works on the principle of conversion of combined kinetic energy and potential energy
of the braking system directly into the electrical energy using generator and stores the generated energy in
storage devices.
•Regenerative braking of EV is influenced by various factors which include state of charge (SOC) of battery,
electrical system design, and generation ability of motor and road adherence conditions
•Studies revealed that the driving range can be improved up to 8% to 25% using regenerative braking and up
to 50% of the total brake energy can be recycled in the urban driving cycle
•In regenerative braking the main challenge is to synchronize between the friction and regenerative braking,
and to optimize the braking torque and distribute it properly in order to optimize the braking performance
and energy recovery.

28. Electric Motor

29. Classification of Electric Motors

30. Types of Motors
•Synchronous Motors:
1.Permanent Magnet Synchronous Motor (PMSM)
2.Stepper Motor
3.The Switched Reluctance Motor

•Asynchronous Motors (Induction Motor)

•Direct Current Motors
1.Brushed DC Motor
2.Brushless DC Motor

31. Synchronous Motors -Permanent Magnet
Synchronous Motor (PMSM)

•This motor is driven by a sinusoidal signal to achieve lower torque ripple.
•The sinusoidal distribution of the multi-phase stator windings generates a sinusoidal flux
density in the air gap that is different from BLDC motor’s trapezoidal flux density.
•This motor possesses feature of an induction motor and a brushless dc motor. The
motor has a permanent magnet rotor and winding on its stator. Furthermore, the stator
of this motor is designed to produce sinusoidal flux density which resembles that of an
induction motor.
•The power density of this motor is higher than induction motors with the same ratings
since there is no stator power dedicated to magnetic field production. Today, these
motors are designed to be more powerful while also having a lower mass and lower
moment of inertia. This motor can generate torque at zero speed, highly efficient and
produces high power density compared to an induction motor. However, this motor
requires a drive to operate.
•To achieve the specifications of high torque at low speed, high density and high
efficiency, this motor uses variable frequency drive. However, the VFD control technique
increases the complexity of the system and hence requires careful attention to precisely
control its speed. Hence the cost of this motor is on the higher side as compared to the
induction motor.

32. Synchronous Motors -Stepper Motor
•The stator of a stepper motor consists of concentrated winding coils, while the rotor
is made of soft iron laminates without coils. Torque is produced in these motors
when the current switches from one set of stator coil to the next coil, the switching
currents from stator windings generates magnetic attraction between rotor and
stator to rotate the rotor to the next stable position, or "step".
•The rotational speed is determined by the frequency of the current pulse, and the
rotational distance is determined by the number of pulses. Since each step results in
a small displacement, a stepper motor is typically limited to low-speed position-
control applications.
•The ability to move a specific step makes these devices commonly used in
positioning mechanisms. Stepper motors are characterized by their moving and
holding torque which if exceeded the motor slips and hence the motor loses count.
This motor produces torque through magnetic reluctance, magnetic attraction or
both. The motor doesn’t offer dynamic speed control.
•The motor can only be accelerated at full toque to full speed and decelerates at full
torque. Hence, the motor offers greater torque for a given speed. Therefore, this
motor is ideal for precision and position control purposes, making it unsuitable for
EV application.

33. Synchronous Motors -The Switched Reluctance
Motor

•The rotor in the Switched Reluctance motor (SR) cannot
generate magnetic field around itself because of the absence
of coils in the rotor, therefore no reactive torque is produced
in an SR motor.
• Torque in these motors is produced when a stator phase is
energized, the stator pole pair attracts the closest rotor pole
pair toward alignment of the poles .
•This way, high-torque ripple is generated which contributes to
acoustic noise and vibration. However, due to its simple
design, SR motor is very economical to build, and is perhaps
the most robust motor available.
•This motor relatively produces lower torque compared with
the stepper motor. Hence, its use is not popular in EV
application.

34. Asynchronous Motors (Induction Motor)

•In this motor, the current in rotor winding is obtained from the
field of the stator winding by electromagnetic induction. The
rotor current is now utilized for torque production.
•The popular asynchronous motor available is the induction
motor.
• In this motor, a sinusoidal AC current is used to excite the
stator to create a rotating magnetic field that induces a current
in the rotor; the induced current in the rotor generate a relative
magnetic field in the rotor.
•The magnetic fields in the rotor and the stator run at slightly
different frequencies and hence generate torque.
•The induction motors are characterized with cheaper cost,
absence of brushes, commutators and low maintenance.
•These features make the induction motor attractive in EVs.
However, the need for converting the power supply from AC to
DC demands more circuitry and hence complex control
schemes.

35. Direct Current Motors:Brushed DC Motor
•A brushed DC motor consists of a commutator and brushes that
convert a DC current in an armature coil to an AC current.
•As current flows through the armature windings, the
electromagnetic field repels the nearby magnets with the same
polarity, and causes the winding to turn to the attracting magnets of
opposite polarity.
•As the armature turns, the commutator reverses the current in the
armature coil to repel the nearby magnets, thus causing the motor
to continuously turn.
•This motor can be driven by DC power, hence it is very attractive for
low-cost applications.
•However, some drawbacks of brushed DC motor are the arcing
produced by the armature coils on the brush-commutator surface
generating heat, wear, and electromagnetic interference (EMI) .
• These characteristics of the brushed motor indicate that it is more
suitable in applications where high efficiency is not a major concern.
This renders use of this type of motor less attractive in EV
applications.

36. Direct Current Motors:Brushless DC Motor
•The BLDC accomplishes commutation electronically using rotor position
feedback to determine when to switch the current.
•This motor is built with a permanent magnet rotor and wire-wound stator
poles. The rotor is formed from permanent magnet and can alter from
two-pole to eight-pole pairs with alternate North (N) and South (S) poles.
•The stator windings work with the permanent magnets on the rotor to
generate a uniform flux density in the air gap.
•This permits the stator coils to be driven by a constant DC voltage (hence
the name brushless DC).
•The rotor position of a BLDC sensed using hall effect sensors is very
important, this gives the information about winding that is energized at
the moment and the winding that will be energized in sequence .
•Whenever the rotor magnetic poles pass near the hall sensors, they give a
high or low signal, suggesting the N or S pole is passing near the sensors.
The exact order of commutation can be estimated, depending upon the
combination of these three hall sensor signals.