Week-6 Challenge: EV Drivetrain

Q.1-

Electrical Vehicle Types –

Three main types of Electrical Vehicle –

1 - Battery Electrical Vehicle –

      Battery Electric Vehicles, also called BEVs and more frequently called EVs, are fully electric vehicles with rechargeable batteries and no gasoline engine. All energy to run the vehicle comes from the battery pack which is recharged from the grid.

2 – Plug in Hybrid Electric Vehicles –

     Plug-in Hybrid Electric Vehicles, or PHEVs, have both an engine and electric motor to drive the car. Like regular hybrids, they can recharge their battery through regenerative braking. They differ from regular hybrids by having a much larger battery, and being able plug into the grid to recharge.

3 – Hybrid Electric Vehicles –

Hybrid Electric Vehicles, or HEVs, have both a gas-powered engine and an electric motor to drive the car. All energy for the battery is gained through regenerative braking, which recoups otherwise lost energy in braking to assist the gasoline engine during acceleration. In a traditional internal combustion engine vehicle, this braking energy is normally lost as heat in the brake pads and rotors. Regular hybrids cannot plug into the grid to recharge and cannot charge with EVgo.

The Basically Three types of Power Converter –

1 – AC – DC Converter

2 – DC – DC Converter

3 – DC – AC Converter

1 – AC – DC converter –

In The Electric Vehicle are required various stages power conversion. The AC – DC    converter are use in charging of EV battery .

The battery storge energy in DC form so its required AC in to DC conversion.

In HEV vehicle its required AC – DC converter.

2 – DC – DC Converter –

The AC – DC converters are generate the high power. We know the vehicle are used numbers of low volt component lighting system , sensor , control system ect . so its required low level DC volt so DC – DC converters are use in Vehicles. The converter are convert voltage level in desire voltage levels also known as choppers.

3 – DC – AC Converter –

DC to AC converter are used in convert the DC in to AC known as the inverter.

The battery power DC its converts in to AC . The AC power is supply to Motor.

The use in the HEV and Plug in HEV vehicles are mostly required.

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'.

 

Q.2 -

Given -

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

                

Rated armature voltage is given – 72v

Duty cycle – 70%

Voltage – Va * Duty cycle

                 72 * 0.7 - 50.4v

Torque equation –

T - k Φ /Ra * [V - k Φ* ω]

we known

k φ – 0.7

Ra- 0.5

T = (0.7/0.5)*[50.4-0.7* ω]

   = 1.4*[50.4-0.7* ω]  =  70.56 – 0.98 ω  epn – 1

Given

 

T = Tv

70.56 – 0.98 ω = 24.7 + 0.0051 ω^2

0.0051 ω^2 + 0.98 ω + 24.7 - 70.56 = 0

0.0051 ω^2 + 0.98 ω – 45.86 = 0

 Slow this equation get the two value –

ω-38.91  / -231.071

speed cannot be negative so we select –

ω-38.91 

Rpm – 38.91*9.54 – 371 rpm

 So steady state speed is – 371 rpm at 70% duty cycle.

 

 

Q,3 -

The developing the mathematical model useing the given equation -

ω">ω=   V/Kϕ">ϕ -Ra/Kϕ">ϕ^2    .T

steps -

1 - Open the Matlab simulink

2 - Select the blank model.

3 - Given equation are requred 3 constant block - Input Voltage ,Motor constant k,Armature Resistance Ra.

4 - Ramp block to useing to Troque T.

5 - Three Prodouct block are use.

6 - 1 Square block are use.

7 - One add block .

8 - Dispaly and scope block are select.

As per the equation the set the simulink model and run the MODEL.

 

Q.4

 

 Explaination in brief on author’s perspective. 

Induction Versus DC Brushless Motors

• In this block are authors are explain the engine of gas powered vehicles, engines are not all are same There are all engine types are suit to personal requirement and price and performance .
• This fact also applicable in ev drive.
• In this blog the indicating the possibility to generating  new technology In this today BLDC motor ,Induction motor are mostly used rather than dc brus motor .
•  In this blog Induction motor and brushless dc motor positive side and negative side are indicating
• Author emphasis on electric motors and how do they work. He mentioned that main difference between 3 phase induction motor and the DC brushless motor is their rotor.
• He liked induction motor as it has no magnets, the motor has the ability to start under load. No inverter is needed. With induction, as machine size grows, losses do not necessarily grow. Thus, induction drives may be the favoured approach where high-performance is desired.  He mentioned drawbacks of induction motors like they cannot operate on DC, also when operated from utility power, they have limited starting torque and somewhat limited running peak torque capabilities as Shaft speed is proportionate to line frequency.
• He mentioned some advantages of dc brushless drive like much less rotor heat is generated, DC brushless drive can also operate at unity power factor.
•  Author mention  in future the more stability are getting in EV automotive sector because of new technology and idea are generated.