Week-6 Challenge: EV Drivetrain

Q1) Power converter use in HEV & EV

Circuit use in power converter

• AC-DC Converter ( Directly in Board)
• DC-DC Converter
• DC-AC Converter

In HEV & EV vehicle power converter is the main element to drivetrain cycle

Because of Is converted available Energy into required Energy

AC To DC converter:-

IMAGE:-1 IMAGE:-2

IMAGE 3

• Is on board converter which is convert Alternating current into Direct current
• It is also use in PEV
• Vehicle run on External supply current

DC To DC converter :-

• It use in regenerative power circuit
• Its use to interface the element in a electric power train By boosting or Chopping the voltage level
• Its control the all element voltage which is obtain from small element to big as like braking and suspension

DC To AC Converter :-

• work as like Inverter
• It required to convert DC power to AC power for electric machine

Q2) Numerical

Given Data:-

1. Battery voltage = 72V
2. Armature Current = 400A
3. Armature Resistance= 0.5Ω
4. Motor Constant =K_Φ=0.7
5. Chopper switch frequency = 400HZ
6. Duty cycle = 70%ω

Calculation:-

Vehicle Output Voltage (v_v)=Battery voltage * Duty cycle

= 72*0.70

Vehicle Output Voltage (v_v)=50.4v

Euation of vehicle torque is

T_v=

Where

• T_v= vehicle torque (N-m)
• V_V=Vehicle voltage(volts)
• ω=steady state speed of vehicle(rps)
• K_Φ=motor constant
• R_a=Armature resistance

Putting all the values in above equation

T_v=

T_v=70.56-0.98*ω……………….1

T_v=24.7+0.0051ω²………………2

Solving above Two Equation

70.56-0.98*ω=24.7+0.0051*²

We get quadratic Equation

0.0051* ω²+0.98*ω-46.94=0

Roots of Quadratic equation

ω=38.85 rad/s and ω=-230.95 rad/sec

we take positive value

So Steady state values is 38.85 Rad/sec

Or

Steady state values is =371 RPM

Q3) motor euation in metlab file

Block diagram element

• Ramp
• Constant
• Addition
• Division
• Product
• Square
• Display
• scope

Power VS time Scope

Speed VS time

Q4) Induction Versus DC brushless motor by Wallly Rippel, Tesla

In the beginning, author describes the dominance of Internal Combustion Engines (ICE) in the world of automobile industry and also discuss different types of engines.

He explains that all engines were similar and it was up to the user to select according to their requirement. He also speaks about induction motor and brushless DC motors and presents his view that these two technologies will be widely used for the coming years.

Then he explains the working of both 3-phase induction motor and a brushless DC motor.

Now the author has done comparison between these two technologies and stated some advantages and disadvantages of each.

Induction motor have some advantages like: it has no magnets. The motor has the ability to start . under load. No inverter is needed. Some disadvantages of Induction motors are: They cannot operate from DC: AC is a must. Shaft speed is proportionate to line frequency.

Hence, when used with utility power, they are constant speed machines. When operated from utility power, they have limited starting torque and somewhat limited running peak torque capabilities, when compared to DC type machines.

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

Some disadvantages of Brushless DC motor are: as machine size grows, the magnetic losses increase proportionately and part load efficiency drops. Permanent magnets are expensive and difficult to handle due to very large forces that come into play when anything ferromagnetic gets close to them.

Finally the author couldn't choose which drive is better than the other but makes it clear that DC brushless drives will likely continue to dominate in the hybrid and coming plug-in hybrid markets, and that induction drives will likely maintain dominance for the high-performance pure electrics.