Week-6 Challenge: EV Drivetrain

Question 1

Power electronic converter :

Power electronics converters mainly comprise of solid-state switches, such as Power MOSFET, Power BJT, IGBT, Thyristor, etc., and lossless components, namely inductors and capacitors. Inductors and capacitors are ideally suited for use in power converters as the power loss in these components are zero as compared to resistance

Types : there are mainly convers are classified into 4 types. They are

• AC to AC converters

An AC to AC converter simply means a device which can convert AC waveforms to another AC waveform. The output voltage and frequency can be managed according to requirements and usage

• AC to DC converters

The term AC to DC converter refers to a switch mode power supply that takes an AC input and converts it to a DC output. They commonly known as Rectifiers

• DC to DC converters

A DC-to-DC converter is a circuit or device that converts direct current (DC) from one voltage level to another. They are commonly known as Choppers

• DC to AC converters

The electrical circuits that transform Direct current (DC) input into Alternating current (AC) output are known as DC-to-AC Converters.

They are commonly known as Inverters

Question 2

Given data

• Rated armeature voltage = 72 volts
• Rated armeature current = 400 A
• Armeature resistance (Ra) = 0.5 ohms
• Kphi = 0.7 volt second
• Speed torque characterstics = T = 24.7 + 0.0051* (w^2)
• Duty cycle(d) = 70% (it means 70/100 = 0.7)

Applied voltage at load(V) = Rated voltage * duty cycle

72*0.7 = 50.4

Substite all values in standard speed torque characterstic equation

T = ((V*Kphi) - w*(Kphi^2))/Ra

= ((50.4*0.7) – w*(0.49))/0.5

= 70.56 – 0.98*w

Compare this with given equation

24.7 + 0.0051* (w^2) = 70.56 – 0.98*w

0.0051*(w^2) – 0.98*w - 45.86 = 0

By solving we get

w = 38.91,-231.07

speed cant be negative

Therefore the required steady stste speed is 38.91

Question 3

Steps to develop a simulink model :

1.For the values of voltage, Kphi, Armeature Resistance, Torque a constant block is taken

2.Formula of speed wrt torque

ω = V/Kϕ -Ra/Kϕ^2*T

3.according to the formula v and Kphi are divided using constant block

4.similarly armeature resistance and Kphi^2 is divided using divide block

5.Ra/Kphi^2 and torque is multiplied using prosuct block

6.As per the equation all these are subtracted from V/Kphi using subtract block

7.Speed is shown using display block

8. All the values are taken from the secoond question from same challange

9. finally speed is came out as 38.92(result)

Question 4

Author’s point of view

Aadhar says that how engines took domination over the world in past and how it is choosen by all. Although people are not satisfied with it and as per the personal requirements they choose the best for them. (For example in prices, performance etc).

In now a days it is similar to electric vehicles. For example in batteries, first they choose lead acid batteries later it is replaced by lithium and DC will be replaced by DC brushless or induction no one can predict the future.

At first the author took closer look in the common points and working of both types. Later the author compare both types and he points out the advantages and disadvantages of both brushless and induction type.

Both the types have advantages and disadvantages.

S.no	Brushless	Induction
	Advantages	Advantages
1.	Less rotor heat is generated.	It don’t require magnets.
2.	Peak point efficiency is higher.	Doesn’t require inverter.
	Disadvantages	Disadvantages
1.	It includes permanent magnets.	They cannot operate from DC, AC is must.
2.	It requires inverter.	Limited running torque, even limited peak torque.

Finally, the author was not able to decide which one is best. He concluded that DC brushless will dominate in hybrid and induction will dominate in pure electric. He let the destiny to decide which one will be in more usage and more likeable.