Week-6 Challenge: EV Drivetrain

1. POWER CONVERTERS IS MADE UO OF HIGH POWER FAST ACTING SEMICONDUCTORS SUCH AS BJTS,MOSFETS IGBTS ETC.,

TWO TYPES OF STEP CONVERTERS ARE THERE .

• STEP UP
• STEP DOWN.

BASICALLY FOUR TYPES OF POWER  CONVERTER ARE PRESENT .

1. DC TO DC CONVERTER
2. DC TO AC CONVERTER
3. AC TO AC CONVERTER 
4. AC TO DC CONVERTER

DC TO AC : CONVERTS DC POWER  FROM BATTERY INTO AC POWER IN AMOTOR CHANGES THE SPEED BY CHANGING FREQUENCY.

DC TO DC:  DEVICE THAT ACCEPTS DC INPUT VOLTAGE INTO  DC OUPUT VOLTAGE  INA POWER ELECTRONICS DEVICES.

AC TO AC : CONVERTS AC WAVE FORMS WITH ONE PARTICULAR FRQUENCY AND MAGNITUDE TO AC WAVE FORM WITH ANOTHER FREQUENCY AND MAGNITUDE.

AC TO DC :CONVERTS  AC INPUT VOLTAGE  INTO DC OUTPUT VOLTAGE WITH ALMOST SAME VOLTAGE RANGE. AND ALSO KNOWN AS RECTIFIER.

CONCLUSION: THEREFORE  ALL THE FOUR CONVERTERS ARE USED .

•  BUT IN THE CASE OF EV S AND HEVS ONLY THREE CONVERTERS  ARE USED EXCEPTS AC TO AC CONVERTER.
• BECAUSE BATTERY NEEDS ONLY DC STORE POWER.

2. TORQUE FORMULA:

         T= V.K/R-K^2.W/R.

•  RATED VOLTAGE =70V
• DUTY CYCLE=70%
• SUPPLIED  VOLTAGE= 70/100*70=50.4V.
• TORQUE T=(V*Kphi)Ra-(w/Ra)*(Kphi)^2.
• w is speed of motor k phi is speed constant.

substituting v=50.4v.Ra=0.50ohms.

kphi=0.7

T=(50.4*0.7)/0.5-(0.7)^2*(w/0.5)

T= 70.56-0.98w  (2)

and 

T=24.7+0.0051w^2   (3)

equating 2 and 3

 70.56-0.98w=24.7+0.0051w^2

0.0051w^2+0.98w-45.86=0

solving

 w= 39.81,-231.07

we can take speed as positive w= 38.91rad/sec.

3.we have the equation 

w=v/k-Ra/k^2.T

v=72 v

Ra=0.5ohms

k=0.7 volts

 T= 70 

result is  7129.

4. DC BRUSHLEES MOTOR ARE USED WHICH PRODUCES ROTATING MAGNETIC FIELD PERMANENT MAGNETS ARE USED . WHICH INDUCES CURRENT AND CURRENT FORCE RESULTS IN ROTATIG THE ROTOR.

• BUT IN INDUCTION MOTOR CURRENT IS SUPPLIED  TO STATOR REULS IN GENERATION OF EMF, IT COMES IN CONTACT WITH ROTOR HAS SQUIRREL CAGE  PRODUCES CURRENT  INTHE ROTOR.
•  MAIN DIFFERENCES IS HEAT IS LESS IN BRUSHLESS MOTOR   THAN THE INDUCTION MOTOR.
• PEAK POINT EFFICIENCY IS HIGH FOR THIS MOTOR LIKE BRUSHLESS.
• COST IS HIGH FOR BRUSHLESS COMPARED TO INDUCTION MOTOR.
• SPEED VARIATION  CONTROL IS DIFFICULT IN IM.

CONCLUSION: FROM THE POINTS LISTED ABOVE 

                        BOTH OF THEM SHOULD BE  DEVELOPED SIDE BY SIDE BECAUSE BOTH HAVE ITS OWN ADVANTAGES AND DISADVANTAGES.