Week-6 Challenge: EV Drivetrain

1.

AC/DC converters

As we considering fully electric vechicle when the AC supply put to the vehicle, The AC power will converted to DC using any half wave or full wave rectifier as designed.In the rectifier some capacitor are used to filter to get the pure DC.The half wave rectifier have 2 diode while in full wave it has 4 diodes.

DC/DC conveters

Here we use the DC power that we get from main source . Here we use the BUCKbooster to claibrates the DC power in the as our recirement or to the auxilary load that has been connect to vehicle. Auxilary loads refers to Like air conditioner,music system, security system, displays,lights etc.

DC/AC inverters

As we are using some AC powered motors we have to convert the DC source to AC source regarding to the motor plate rating.For conveting to AC from DC thyrtron/thyristor/IGBT are highly used and we have to set the triggering angle as our motor supply needs.

2.

Given data are:

Rated Armature voltage= 72 V`omega`

Rated armature current= 400 A

Rated armature resistance= 0.5Ω,

KΦ= 0.7 Volt second

Chopper Switching frequency= 400 Hz

According to Vehicle output voltage(Vout):

Vout=Batery voltage *Duty cycle =72*72/100=50.4(vehcile voltage)

Torque equation for vehicle:

Tv=Vv−ω⋅Kϕ/Ra;

Vv=vehicle voltage

ω= speed of vehicle

Kϕ=motor constant

Ra=armature resistance

After substituting all equation values we get

Tv=70.56-0.98*ω

comparing and solving the equation with given equation

we will get,

ω=38.58 rad/s & -230.95rad/s

while we will consider the positive valuue then steady state speed will be:38.85rad/s

3.

matlab model for given equation.

4.

AS the author had been telling about how the world technology are changing with in a glanace of time . He had written about the developments in motors, battery & contactors. The amin concern about the blog is the author had defined about the diffrenece of constructions,working mechanisim ,charatristices, cons & pro about the DC brushless motor and the Induction motor. As brusshless DC motor need a perment magnets and coil winding in construction . Certain types of inverter in needed to rotate the magnetic field to rotates the motor. The inverter used to vary the magnetic field to rotates.The author had been written that the brushlessDC motor are usless if inverter are not been used. The inverters are made with some control codes and positioning sensor feed back.

As the author has been written about the Induction motor construction. In induction motor there 3 balanced winding are in stators while the rotor is a rack of steel slots tightly packed and short circuited. When the 3 phase supply get connected with the motor the stator create rotating magnetic field in which the rotors get cuts the magnetic fields and starts rotating. The induction motor is very much compatible with grid power supply. For controlling the induction motor there are drives are used to controlled it by varying the frequency cycles. Very easy to maintain, cheaper than the DC motor because of using the permanet magnets. and DCmotor inverter drives are so high priced.

Induction motor has no load starts while in brushless DC motor has no starting torques, although both of them have some loss like DC motor never heat up fast meanwhile the induction motor heatup fast. There are some loss in induction motor like eddy current loss,I2R loss. The induction motor cant run in unity power factor while the brushless DC can run easily. Controling torque is the easy in DC motor while in Induction motor is difficult.

Atlast the author has raised the go flag for brushlessDC motor because it is better in majority of case than the induction motor.