Week-6 Challenge: EV Drivetrain

Battery (auxiliary): In an electric drive vehicle, the low-voltage auxiliary battery provides electricity to start the car before the traction battery is engaged; it also powers vehicle accessories.

DC/DC converter: This device converts higher-voltage DC power from the traction battery pack to the lower-voltage DC power needed to run vehicle accessories and recharge the auxiliary battery.

Electric generator: Generates electricity from the rotating wheels while braking, transferring that energy back to the traction battery pack. Some vehicles use motor generators that perform both the drive and regeneration functions.

Electric traction motor: Using power from the traction battery pack, this motor drives the vehicle's wheels. Some vehicles use motor generators that perform both the drive and regeneration functions.

Exhaust system: The exhaust system channels the exhaust gases from the engine out through the tailpipe. A three-way catalyst is designed to reduce engine-out emissions within the exhaust system.

Fuel filler: A nozzle from a fuel dispenser attaches to the receptacle on the vehicle to fill the tank.

Fuel tank (gasoline): This tank stores gasoline on board the vehicle until it's needed by the engine.

Internal combustion engine (spark-ignited): In this configuration, fuel is injected into either the intake manifold or the combustion chamber, where it is combined with air, and the air/fuel mixture is ignited by the spark from a spark plug.

Power electronics controller: This unit manages the flow of electrical energy delivered by the traction battery, controlling the speed of the electric traction motor and the torque it produces.

Thermal system (cooling): This system maintains a proper operating temperature range of the engine, electric motor, power electronics, and other components.

Traction battery pack: Stores electricity for use by the electric traction motor.

Transmission: The transmission transfers mechanical power from the engine and/or electric traction motor to drive .

2. An Electric Vehicle's powertrain with 72V battery pack in shown in the diagram below. The duty ratio for acceleration operation is 'd1' and for the braking operation the duty ratio is 'd2'.

The other parameters of the electric vehicle is given below,

Motor and Controller Parameters:

Rated Armature voltage= 72 V

Rated armature current= 400 A

Ra= 0.5Ω, KΦ= 0.7 Volt second

Chopper Switching frequency= 400 Hz

The vehicle speed-torque characteristics are given by the below equation

What is EV steady state speed if duty cycle is 70%?

T =V.K-K^2.W/R^2.

T = Torque

V = Armature voltage.

R = resistance

W =Speed rad/sec

Compare the equation

24.7+0.0051*w^2 = ((v*K)/R)-((K^2)*w/r)

24.7+0.0051*w^2 = (72*0.7*0.7)/0.5-(0.7^2/0.5)*w

70.56-0.98*w=24.7+0.00051*W^2

w^2+192.15*w-892.15 = 0

w=38.95rad/sec.

3. Develop a mathematical model of a DC Motor for the below equation using Simulink.

ωω= V/Kϕϕ -Ra/Kϕϕ^2 .T

In the beginning author desribes the dominance of ingerbal combustion engine(ICE) iin the world of automobile industry and aslo discuss differ types of engine.In the blog of induction DC brushless motor has a postive and negative side of both the induction and dc motor.

The dc motor is permanent magnets are used which produced a rotating magnetic field. This magnetic field when induces a current in the conductor.This current results in force generation in the rotor and this results in rotaion of motor.

For induction drives ,there rotor has no magnets but instead stacked steel lamination with buried conductors which a shorted structure.Its is the current steel lamination.

Brushless DC motor have some adv. like: much less rotor heat is generated with the DC brushless drive.The peak point energy efficiency for Dc brushless drive is typically be a few percentage points higher than for an induction drive.

Finally the suthor not choose which drive is better than teh other but makes it clear that DC brushless drives will likely continue to dominates in the hybrid and coming plug in hybrid markets.