A detailed presentation about hybrid car and its motor drives.It helps you to understand more about HEV in detail.And also it contains all parts of HEV.
2. CONTENTS
ï¶INTRODUCTION
ï¶ARCHITECTURE OF HEV DRIVETRAINS
1)SERIES HYBRID DRIVETRAIN
2)PARALLEL HYBRID DRIVETRAIN
3)SERIES-PARALLEL HYBRID DRIVETRAIN
ï¶ELECTRIC MOTOR DRIVES
1)PERMANENT MAGNET(PM)MOTOR DRIVES
2)INDUCTION MOTOR(IM) DRIVE
3)SWITCHED RELUCTANCE MOTOR(SRM) DRIVE
ï¶ENERGY STORAGE
1)CHEMICAL BATTERIES & ULTRACAPACITORS
2)HYBRID ENERGY STORAGE
ï¶CONCLUSION
3. INTRODUCTION
A hybrid electric vehicle (HEV) uses two power sources to power the vehicle.
At present, one power source is internal combustion (IC) engine (gasoline or
diesel fueled) and the other is chemical batteries plus an electric motor drive.
4.
5. CONCEPT OF HYBRID DRIVETRAIN
ï” â9â Types available patterns of combining the power
flows to meet load requirments.
ï” Load power
ï” Load power decomposed into âSteady
state(average)power & Dynamic power
8. SERIES HYBRID DRIVETRAIN
ï” By adding a small IC engine/generator to the battery powered
pure electric vehicle (EV) in order to make up the energy
shortage of the batteries
9. Advantages
ï” Mechanical decoupling between IC engine & driven wheels allows
the IC engine operating at very narrow optimal region
ï” Single torque source(electric motor) to the driven wheels simplifies
the speed control
ï” nearly ideal torque-speed characteristic of electric motor makes
multigear transmission unnecessary
ï” simple structure and drivetrain control and easy packaging
10. Disadvantages
ï” Twice the energy form conversions cause more energy losses
ï” Two electric machines are needed
ï” A big traction motor since it is the only torque source of the driven
wheels.
12. PARALLEL HYBRID DRIVETRAIN
ï” The engine and electric motor can directly supply their torque to the
driven wheels through a mechanical coupling
ï” Mechanical coupling may simply be a gearbox, pulley-belt unit or
sprocket-chain unit, even a single axle
13. Advantages
ï” Energy loss is less due to engine and electric motor directly supply
torques to the driven wheels and no energy form conversion occurs
ï” Compactness due to no need of the generator and smaller traction
motor
14. Disadvantages
ï” Mechanical coupling between the engine and the driven wheels,
thus the engine operating points cannot be fixed in a narrow
speed region
ï” Complex structure and control
17. ï” The engine power is split into 2 parts
1)Transferred to the Drivetrain
2)Generator
ï” Series hybrid â generator/motor speed is âve(opposite direction vs the torque)
ï” Parallel hybrid â Generator speed is +ve the generator/motor operates in
motoring mode,adding power to driven wheels
ï” Engine speed can be optimized by controlling the generator/motor speed
ï” Planetary gear unit need for these functions
19. Advantages
ï” Combines the advantages of series & parallel drivetrain
ï” An additional electric machine and planetary unit makes the drivetrain more
complicated
ï” Instead of Planetary gear unit a floating-stator electric machine (Transmotor)
Disadvantages
22. Permanent Magnet(PM)
ï” Instand of rotor winding using Permanent Magnet
ï” The overall weight and volume can be significantly reduced for given output torque,
resulting in higher torque density
ï” Due to the absence of rotor winding, rotor cu losses will not come in effect
ï” Their efficiency is inherently higher than that of induction motors
ï” The brushless dc motor and interior permanent magnet motor are two typical motor
drives for HEV applications
23. ï” In PM BLDC field weakened through production of a stator field component,
which opposes the rotor magnetic field
ï” The speed ratio âxâ is usually lees than 2
24. ï” Recently, the use of additional field windings to extend the speed range of PM
brushless dc motors has been developed
ï” PM hybrid motor = PMs + Field windings
ï” This can achieve a speed ratio around 4
ï” Major drawback of a relatively complex structure. The speed ratio is still not enough
to meet the vehicle performance requirement, especially for off-road vehicles.
25. INDUCTION MOTOR
ï” Field orientation control (FOC) of an induction motor can decouple its torque
control from field control
ï” The motor to behave in the same manner as a separately excited dc motor
ï” Extended speed range is accomplished by flux weakening
26. ï At the critical speed (Wmc) the breakdown torque is reached.
ï The machine at the maximum current beyond this speed will stall the machine.
ï A properly designed induction motor, e.g., spindle motor, with FOC can achieve a
field weakened range of about three to five times its base speed.
27. SWITCHED RELUCTANCE MOTOR(SRM)
ï” Its simple and rugged construction
ï” Simple control
ï” Ability of extremely high speed operation
ï” Hazard-free operation.
28. ï” SRM can inherently operate with extremely long constant power range.
ï” Highly favorable for vehicle traction application.
ï” The major disadvantage of SRM drive is the high torque ripple and acoustic noise
ï” Extended speed range by reducing the motor size and weight.
ï” High-speed operation is expected to reduce the torque rating and, thus, the
current rating
ï” Due to high speed there will be high mechanical loss(Aerodynamics drag &
viscosity)
ï” Reduce these losses the shape of the rotor should be optimally designed for SRM
drive
29.
30. Chemical Batteries & Ultracapacitors
ï” Chemical Batteries
ï” Almost all the vehicles use chemical batteries as their energy storage
ï” Li-ion battery commonly used and its peak power upto 300 W/kg
ï” Li-ion high power & high energy battery is having peak power upto 4000 and
600 respectively
ï” Low cost batteries
31. ï”Ultracapacitor
ï” High specific power
ï” High efficiency
ï” Excellent temperature adaptability
ï” Long service life
ï” But it has suffered from very limited specific energy
ï” Unit power cost is lower than that of batteries
ï” Difficult to use Ultracapacitor alone as energy storage on HEV
32. Hybrid Energy Storage
ï” Combination of Ultracapacitor & Chemical Batteries
ï” Energy storage with high power and high energy can be obtained
33. Advantages
ï Battery current leveled by passively connected ultracapacitor
ï Small battery pack
ï High operating efficiency
ï Easy thermal management
ï Longer battery life
34. CONCLUSION
ï” Using the concept of Hybridization of cars results in better efficiency and also
saves a lot of fuel in todayâs fuel deficit world.
ï” A hybrid gives a solution to all the problems to some extent(Air pollution).
ï” In the short run HEVs seem to be a viable alternative
35. REFERENCES
[1]Mehrdad Ehsani, Fellow IEEE, Yimin Gao, and John M. Miller, Fellow IEEE, âHybrid Electric
Vehicles: Architecture and Motor Drivesâ,page 719-728, Vol. 95, No. 4, April 2007 ,proceedings of
ieee
[2]Wikipedia
