Final Project: Design of an Electric Vehicle

PROJECT : DESIGN OF AN ELECTRIC VEHICLE

AIM:

TO Create a MATLAB model of electric car which uses a battery and D.C. motor.Choose suitable block from powertrain block set.Prepare a report about your model including following.

Objectives:

1. System level configurations

2.Model parameters

3.Results

4.Conclusion

Electric car is a vehicle that is fully or partially propelled by electric motors,using energy stored in rechargeble batteries.

1.The first practical electric cars were produced in the 1880s.Electric cars were popular late 19th century and early 20 th century.

2.Innovation and advanced development in the internal combustion engines (ICE) and mass production of cheaper gasoline vehicles has led to a decline in the use of electric vehicles.

3.Different type of electric cars changed and are developed continuosly giving users and potential users choices.Today the world is increasingly familiar with the terms BEV,HEV,PHEV and FCEV.

How does an electric car work ?

• When pedal of the car is pressed then,controller takes and regulates electrical energy from batteries and inverters.
• With the controller set,the inverter then sends a certain amount of electrical energy to the motor ( according to the depth of pressure on the pedal ).
• Electric motor converts electrical energy into mechanical energy.Rotation of the motor rotor rotates the transmission.So the wheels turn and then car moves.

Types of electric cars:

1.Battery electric vehicle ( BEV)

2.Hybrid electric vehicle (HEV)

3.Plug in hybrid electric vehicle (PHEV)

4.Fuel cell eletric vehicle (FCEV)

1.Battery Electric Vehicle (BEV):

• It is also called as ,All-electric vehicle (AEV),runs entirely on a battery and electric drive train.
• This types of electric cars do not have an ICE.Energy is stored in a large battery pack that is charged by pluggig into the electricity grid.
• The battery pack,in turn,provides power to one or more electric motors to run the electric car.

Components of BEV-

• Electric motor
• inverter
• Battery
• Control Module
• Drive train

Working principle of BEV :

• Power is converted from DC battery to AC for the electric motor.
• The acceleration pedal sends a signal to the controller which adjust the vehicle speed by changing the frequency of the AC power from the inverter to the motor.
• The motor connects and turns the wheels through a cog.
• When the brakes are pressed or the electric car is decelerating,the motor becomes an alternator and produces power which is send back to the battery.

Examples-Volkswagon e golf, Tesla model 3, BMW i3 , Chevy bolt, Chevy spark, Nissan LEAF,Ford focus electric,Hyundai ioniq,Karma revera.

2.Hybrid Electric Vehicle (HEV):

• This type of hybrid cars is often called as standard hybrid or parallel hybrid.
• HEV has both an ICE and an electric motor.
• In this types of electric cars,internal combusion enegine gets energy from fuel,while the motor gets electricity from batteries.
• The gasoline engine and electric motor simultaneously rotate the transmission,which drives the wheels.
• The difference between HEV compared to BEV and PHEV is where the batteries in HEV can only charged by the ICE,the motion of the wheels or a combination of both.
• There is no charging port,so that the a battery can not be recharged from outside of the system.

Components of HEV

• Engine
• Electric motor
• Battery pack with controller and inverter
• Fuel tank
• Control module

Working principle of HEV:

• Has a fuel tank that supplies gas to the engine like a regular car.
• It also has a set of batteries that run an electric motor.Both the engine and electric motor can turn the transmission at the same time.

Examples:

Honda civic hybrid , Toyota prius hybrid,Toyota camry hybrid.

3.Plug in hybrid electric vehicle ( PHEV):

• PHEV is a type of hybrid vehicle that both an ICE and motor,often called as series hybrid.This type of electric cars offer a choice of fuels.
• This tyoe of electric cars is powered by a conventional fuel or an alternative fuel and by a rechargble battery pack.
• The battery can be cahrged up with electricity by plugging into an electrical outlet or electric vehicle charging stations.
• PHEV typically can run in at least two models - All electric model,in which the motor and battery provide all the car's energy.
• Hybrid mode,in which both electricity and gasoline are employed.

Components of PHEV:

• Electric motor
• Engine
• Inverter
• battery
• Fuel tank
• control module
• Battery charger ( if onboard model )

Working principle of PHEV:

• PHEVs typically startup in all electric mode and operate on electricity until their battery pack is depleted.
• Some moduleshift to hybrid mode when they reach highway cruising spped,generally above 60-70 miles per hour.
• Once the battery is empty,the engine takes over and the vehicle operates as a conventional, non plug in hybrid.
• In addition to plugging into an outside electric power source,PHEV batteries can be charged by an combustion engine or regenerative braking.
• During braking,the electric motor acts as generator,using the energy to charge the battery.The electric motor supplements the engine's power as a results smaller engines's power as a results smaller engines can be used,increasing the car's fuel efficiency without compromising performance.

Examples:

• Porsche cayenne SE-hybrid, chevy voot,Chrysler pacifica,ford c maxenegine,Mercedes S550e etc.

4.Fuel Eell Electric Vehicle ( FCEV):

• Fuel cell elecric vehicles (FCEVs),also known as fuel cell vehicles (FCVs),or zero emission vehicle,are types of electric cars that employ fuel cell technology to generates the electricity required to run the vehicle.
• In this type of vehicles,the chemical energy of the fuel is converterd directly into electric energy.

Components of FCEV:

• Electric motor
• Fuel cell stack
• Hydrogen storage tank
• BAttery with converter and controller

working principle of FCEV:

• The working principle of a fuel cell electric car is different compared to that of a plug in electric car.
• This type of electric cars is becauses the FCEV generates the electricity required to run this vehicles on the vehicle itself.

Examples:

Toyota mirai,Hyundai tuscon FCEV,Riversimple rasa etc.. .

Electric car components-

• Electric car or vehicle component and function depend on the car type.

(a).Tranction battery pack:

• The function of the battery in an electric car is as an electrical energy storage system in the form of direct current electricity (DC).
• If it gets a signal from the controller,the battery will flow DC electrical energy to the inverter to then be used to drive the motor.
• The type of battery used is a rechargble battery that is aranged is such a way as to form what is called a traction battery pack.
• There are various types of electric car batteries.The most widely used is the type of lithium ion batteries.

(b).Power inverter:

• The inverter functions to change the direct current (DC) on the battery into an alternating current (AC) and then this alternating current is used by an electric motor.
• in addition,the inverter on an electric car also has a function to change the AC current when regenerative braking to DC current and then used to rechage the battery.
• The type of inverter used in some electric car models is the bi-directional inverter category.

(c).Controller:

• The main function of the controller is an a regulator of electrical energy from batteries and inverters that will be distributed to electric motors.
• While the controller itself gets the main input from the car pedal( which can set by the driver ).
• This pedal setting will determine the frequency variation or voltage variation that will enter the motor and at the same time determine the car's speed.
• In brief,this unit manages the flow of electrical energy delivered by the traction battery,controlling the spped of the electric traction motor and the torque it produces.This components will determine how electric car work.

(d).Electric traction motor:

• Because the controller provides electrical power from the traction battery,the electric traction motors will work turning the transmission and wheels.
• Some hybrid electirc cars use a type of generator motor that performs the functions of propulsion and regenerative.In general,the type of electric motor used is the BLDC ( brushless DC motor).

(e).Charger:

Is a battery charging device.Chargers get electricity from outside sources,such as the utility grid or dolar power plants.AC electricity is converterd into DC electricity and then stored in the battery .

Two types of electric car charger:

1.On board charger:The charger is located and installed in the car.

2.Off board charger:The charger is not located or not installed in the car.

(f).Transmission:

The transmission transdfers mechanical power from the electric traction motor to drive the wheels.

(g).DC-DC converter:

This one of electric car parts that to converts higher voltage DC power from the traction battery pack to the lower voltage DC power needed to run vehicle accessories and recharge the auxiliary battery.

(h).Thermal systems:

This system maintains a proper operationg temperature range of the engine, electric motor,power electronics,and other components.

(i).Charge port:

The charge port allows the vehicle to connect an external power supply in order to charge the traction battery pack.

MODELING OF ELECTRIC VEHICLE:

OBJECTIVES:

• Electric vehicle with fewar components.
• To make a most simple and low run time vehicle model using individual component models.
• To checkout performance parameters speed,SOC,current etc with various drive cycles.
• To play with motor power, vehicle body ( Rolling resistance,Air drag,Weight) inputs.
• To know MATLAB models and their configuration to match with actual vehicles.

BLOCK DIAGRAM OF ELECTRIC VEHICLE

THE SIMULINK MODEL FOR THE ELECTRIC VEHILCE:

Now discuss about model blocks:

1.Drive Cycle Source:

Generates a standard or user-specified longitudinal drive cycle.The block output is the vehicle longitudinal speed.you can import drive cycles fromas predefined sources,Workspace variables,including arrays and time series objects,mat,xls,xlsx,or txt files.Use the fault tracking parameters to identify drive cycle faults wthin specified speed and time tolerances.

2.Longitudinal Driver:

A parametric longitudinal speed tracking controller for generating normalized acceleration and braking commands based on reference and feedback velocities.Use the external actions to input signals that can disable,hold or override the closed loop commands determined by the block.The block uses this priority for the input commands:disable,hold,oveeride.

3.Motor & Controller unit:

(A).Controllled voltage source-

The block represents an ideal voltage source that is powerful enough to maintain the specified voltage at its output regardless of the current passing through it.The output voltage is V=Vs,where Vs is the numerical value presented at the physical signal port.

(B).Controlled PWM Voltage-

This block creates a pulse-width modulated ( PWM ) voltage across the PWM and PEF ports.The output voltage is zero when the pulse is low,and is equal to the output voltage amplitude parameters when high.Duty cycle is set by the input value.Right click the block and select simscape -> block choices to switch between electrical +ref/ref ports and PS input u to specify the input value.At time zero,the pulse is initialized as high unless the duty cycle is set to zero or the pulse delay time is greater than zero.The simulation mode can be set to PWM or averaged.In PWM mode,the output is a PWM signal.In averaged mode,the output is constant PWM siganl.

(C). H-Bridge-

This block represents an H-Bridge motor drive.The block can be driven by the controlled PWM voltage block in PWM or Averaged mode.In PWM mode,the motor is powered if the PWM port voltage is above the enable threshold voltage.In Averaged mode,the PWM port voltage divided by thr PWM signal amplitude parameter defines the ratio of the on time to the PWM period.Using this ratio and assumptions about the load,the block applies an average voltage to the load that achieves the correct average load current.The simulation mode parameter value must be the same for the controlled PWM voltage and H-Bridge blocks.

(D).Current Sensor-

The block represents an ideal current sensor,that is a device that converts current measured in any electrical branch into a physical siganl proportional to the current.Connections and are conserving electrical ports through which the sensor is inserted into the circuit.Connection l is physical siganl port that outputs current value.

(F).DC Motor-

This block represents the electrical and torque characteristics of a DC motor.The block assumes that no electromagnetic energy is lost,and hence the back emf and torque constant have the same numerical value when in Sl units.Motor parameters can either be specified directly,or derived from no-load speed and stall torque.If no information is available on armature inductance,this parameters can be set to some small non-zero value.When a positive current flows from electrical + to ports,a positive torque acts from the mechanical C to R ports.Motor torque direction can be changed by altering the sign of the block emf or torque constants.

4.Battery-

This blocks models a battery.If you select infinits for the battery charge capacity parameter,the block models the battery as a series internal resistance and constant voltage source.If you select finite for the battery charge capacity parameters,the block models the battery as a series internal resistance plus a charge dependent voltage source defined .Coefficient beta is calculated to satify a user defined data point.

5.Controlled Current Source-

The block represents an ideal current source that is powerful enough to maintain the specified current through it regardless of the voltage across it.The output current is l = ls where ls is numeical value presented at the physical signal port.

6.Electrical Reference-

Electrical reference port.A model must contain at least one electrical reference port ( Electrical ground ).

7.Vehicle With Transmission subsystem-

This subsytem includes one simple gear,differential,vehicle body and 4 tires ( magic formula) and all are connected :

(A).Simple Gear-

For engaging the correct gear at the right duration when required.

(B).Differential Block-

Represents a differential which is arranged as a planetary level gear train equipped with an additional level gear transmission between the driveshaft and the carrier.The pinion gear of this transmission is attached to the driveshaft while the large belel crown gear afficed to the carrier.Compliance is not modeled in this block.

(C).Vehicle Body-

Represents a two axis vehicle body in longitudinal motion.The block aerodynamic drag,road incline,and weight distribution between axles due to acceleration and road profile.The vehicle can have the same or a different number of wheels on each axle.Optinally include pitch and suspension dynamics . The vahicle does not move vertically relative to ground.

(D).Tire (Magic Formula)-

Represents the longitudinal behaviour of a highway tirecharacterized by the tire magic formula.The block is build from Tire road interaction (Magic formula) and simscape foundation liberary wheel and alle blocks.

8.Distance Calculation Block-

Mathematical blocks and scope is used to measure the distance travelled by the vehicle.first we had to implement the integater block to indicate the velocity signal that is output from the velocity of the vehicle.Dividen block along with the constant block having a value of 3600 is used to divide the integrated speed.This will give the distance travelled in kilometers.

9.Bus Selector-

This block accepts a bus as input which can be created from a Bus Creator,Bus selector or a block that defines its output using a bus object.The left listbox shows the elements in the input bus.Use the select button to select the output elements.The right listbox shows the selections.Use the up,Down,or remove button to recorder the selections.Check'outpt as virtual bus' tooutput a single bus.

10.Mechanical Reference-

This block represents a mechanical rotational ponit,that is , a frame or a ground.Use it to connect mechanical rotational ports are rigidly affixed to the frame (Ground).

11.Solver Configuration-

Defines solver settings to use for simulation.

RESULT:

Result show in scope.

CONCLUSION:

Here from the result we can conclude that the actual speed of the vehilce is tracing the refered speed from the drive cycle.Here we can also say that to reduce the difference between the actual vehicle velocity and the reference velocity we can optimise or change the parameters including battery voltage or motor loads.