Electric vehicle:- Motor Drive technologies

Motor Drive technologies:

IC engine cannot operate in wide torque and speed range. Therefore it requires support of clutch and multiple transmission gear.

When clutch is engaged IC engine is coupled to gearbox, energy transmit from IC engine to gearbox

IC based engine requires

• Clutch
• Multiple or variable gears
• Differential

Battery electric vehicle

• Clutch is absent
• Normally fixed gears are used
• Differential absent

Requirement of an EV motor compared to industrial motors:

• Maximum torque than rated torque for starting,Hill climbing & overtaking etc.
• EV motors demand high power density & good efficiency
• EV motors desire high controllability , high steady state accuracy and good dynamic performance
• EV motors need to operate in harsh operating conditions such as high temperatures , bad weather and frequent vibration.

Major requirement of an EV motor:

• High torque density and high power density
• Very wide speed range including constant torque and constant power regions
• High efficiency over wide torque and speed range
• Reliability & robustness
• Low cost
• Capable of being integrated with the engine.
• Good voltage regulation

Classification of EV motors:

• Commutator
• DC motors
• Self excited
• Series
• Shunt
• Separately excited
• Wound field
• Permanent Magnet excitation
• Commutator less
• Induction
• Wound rotor
• Cage rotor
• Synchronous
• Wound rotor
• PM rotor
• BrushLess DC
• Sinusoidal- Permanent Magnet Synchronous Motor
• Interior Permanent Magnet Synchronous Motor
• Reluctance rotor
• Doubly salient(both stator & rotor)
• Switched Reluctance Motor
• Stator PM(rotor without PM)
• Field Coil DSPM(field coil is embedded in stator)

Challenges in an Electric Vehicle

Challenges in Battery Electric Vehicle(BEV)

The energy storage is lower than IC engine based vehicle

• Limited driving range(Range Anxiety)
• High Initial cost (Batteries: oversized, costly, replacement, limited cycle life(4-5 years)
• Lack of charging infrastructure
• Effect on power utility grid
• Cost of charging infrastructure
• Discontinuous operation
• Normal charging(5-8 hrs ,110-240V,13-40A,2-4KW)
• Fast charging(20-30 mins,200-400V, 100-200A,50KW)
• Battery swapping( battery bank replaced in station)

Challenges in Conventional HEV(HEV)

• Non zero emissions
• Low energy diversification(it can be only refilled using oil & natural  gas)
• Complex system and Coordination
• System is heavy and bulky
• Variable transmission system
• Transmission loss
• Noise
• Regular lubricant

Challenges in Grid ableHEV(HEV)

• All the challenges of conventional HEV
• Requires installation of on board charger in some vehicle
• Initial cost more due to more battery capacity.

Challenges in Fuel cell EV

• High initial cost
• Fuel Cells
• Lack of hydrogen refueling infrastructure(not commonly available)
• Storage of Hydrogen
• Compressed Hydrogen gas
• Liquid Hydrogen
• Metal Hydride
• Safety concern

Challenges in Ultracapacitors/Ultra Flywheels

• Costly
• Low specific energy
• Cannot be sole energy source.
• UF have safety concern

Overview & types of Electric vehicle

Overview & types of Electric vehicle:

IC Engine requires:

• Starter motor(to start the IC engine)
• Alternator(to recharge the battery once the IC engines starts)

These  two functions are kept together in a device called Integrated Starter Generator(ISG)

ISG connected to the IC engine either through

• Belt driven ISG
• Crank shaft mounted ISG

The function of ISG is it assist the IC engines in various way

Electric vehicle can be classified in various way

• Propulsion device
• Pure Electric vehicle(PEV)
• Battery Electric vehicle(Clutch is not required)
• Fuel cell Electric vehicle (Battery+ Fuel cell)
• Ultracapacitor Electric vehicle(Battery+ UC)
• Ultra Flywheel Electric vehicle(Battery+UF)
• Hybrid electric vehicle(HEV)

Electric motor rating is low in Microhybrid and high in Range Extended

IC engine high rating in Microhybrid and low in Range Extended

• Conventional HEV (refill at filling station or petrol station)
• Microhybrid(ISG, 3 -5 KW)ISG supports starting and stopping of the IC engine.This will enables fuel economy.

ISG can also help in recovery of  energy power during braking.Low power ISG & they are connected through Belt Driven

• Mild Hybrid(ISG,7-15 KW) ISG of higher rating is used. ISG supports starting and stopping & regenerative braking of the IC engine.It also support the IC engine and power shearing during normal operation.
• Full Hybrid(ETV, 50 -60 KW)(IC engine or Electric mode or both)
• It requires a complex  transmission system which is known as Electronic variable transmission(ETV)This device allows to connect the IC engine & motor together.
• Start- Stop, Regenerative braking,Power assist & Electric launch.
• Series Hybrid
• Parallel Hybrid(both the IC engine & Battery based is couple together with a clutch known as Dual clutch transmission.(DCT)
• Series parallel hybrid(special gear system Continuous variable transmission(CVT) which allows all the modes series & parallel operation)
• Complex Hybrid
• Grid - Able HEV (refill both electrically and at filling station)
• Plug in Hybrid(PHEV)

Derived from full hybrid

Mostly operated in blended mode

• Range Extended(REV)
• Derived from Battery  Electric vehicle
• Mostly operated in pure electric mode.
• Energy source
• Battery Electric vehicle
• Hybrid Electric vehicle
• Fuel cell Electric vehicle
• Energy carriers etc

Benefits of using Electric vehicle

Benefits of using EV’s:

Vehicles in use may increase from 700 millions in 2000 to 2.5 billions by 2050. If all vehicles are ICEV then pollution will increase.

• Energy sources
• Pollution
• Efficiency
• Performance
• Capital & operating cost

Energy sources

• Petrol
• Diesel
• Compressed Natural Gas(CNG)
• Hydrogen
• Batteries
• Ultra capacitors
• Ultra flywheel

Pollution

• Particulate matter
• CO2
• NOx
• SOx
• Hydrocarbon
• CH4

Comparison of Capital & operating cost:

• Higher fuel economy than ICEV
• Less maintenance and more reliable
• Recover energy during braking
• Requirement of more space
• More expensive than ICEV
• Due to initial battery cost
• Replacement of Batteries

Historical background of an Electric Vehicle

1834 - Non rechargeable battery operated EV (tricycle) - Thomas Davenport

1874 - After invention of lead acid battery rechargeable EV - David Salomon

1886- Electric Trolley - Frank Sprague

1894 - Popular EV - Electrobat, Columbia ,Victoria and Jamais Contente
( Never satisfied) captured a record of 110 Km/Hr in May, 1899

1900 - USA automobile distribution 38%  - Electric vehicle(EV), 22% -
ICEV & 40% steam powered

Due to Ford T model car and automobile starter(electric ignition) makes EV costlier.

California Air Reserve Board (CARB) established rule that 2% of all vehicle sold
should be Zero Emission vehicle. & increase in alternate energy make demand of EV.

Great Electric car race from Boston to Pasadena, distance 3,490 miles,
Recharging station:53.

1966 - General Vehicle built Electrovair, Electrovan & Electrovette (SCR
based separately excited DC motor with Ni-Zn batteries)

Popular EV in 1990s

1. General motors EV 1 (100KW, Induction motor, Lead acid battery)
2. Nissan Altera EV- 62 KW PMSM, Co -Li)
3. NIES(National Institute of Environmental science) -

In Wheel PMSM & Lead acid battery

1. Reva - Indian make(13 KW , separately excited  DC motor 65 KM/Hr)

Popular HEV

• Toyota Pirus
• Honda Insight

     Popular FCEV(Fuel cell Electric vehicle)

• Ford P 2000,
• Daimler

       Current Popular EV

• Tesla Road star
• Nissan Leaf
• Chevy Bolt

    Current Popular HEV are mostle PHEV (Plug in )( ICE - low rating,Motor - High rating)

• Honda Accord
• Ford Fusion Hybrid
• Lexus
• Volvo
• BMW

BE8254 Basic Electrical & Instrumentation April May 2018 Anna University Question Bank with answers.