Final Project: Design of an Electric Vehicle

Create a MATLAB model of electric car which uses a battery and a DC motor. Choose suitable blocks from Powertrain block set. Prepare a report about your model including following:

Objectives: 

       1. System level configurations

       2. Model parameters

       3. Results

       4. Conclusion

AIM

To Create a MATLAB model of an Electric Vehicle that uses a battery and a DC motor.

OBJECTIVE 

Study about the modeling of Electric Vehicles and the blocks used in MATLAB-Simulink for modeling of EV. Preparing a detailed report on Electric car modelling.

 

Electric Vehicle:

An Electric Vehicle is a vehicle which is propelled by an Traction Motor instead of Internal Combustion engine which uses mixture of fuel and air to move the vehicle. The Traction Motor is powered by an Battery Pack which has number of Lithium Ion cells which are stacked together inside a module through combination of series and parallel connection to form a battery pack. The EV is charged by an External Power supply called as an Electric Vehicle Supply Equipment(EVSE). The Electric Vehicle On board Charger consists of Rectifier and Converter circuit which converts the AC supply into DC supply and then this DC Supply is stepped up to match the battery pack voltage level which is supplied to battery pack. Since On board Charger has limitations due to space constarints it cannot charge Battery at faster Rate. Therefore EVSE is used to charge the EV quickly. If the Power supplied is High Voltage DC directly from EVSE then On board Charger will detect the type of supply and it will bypass the Rectifier and Converter circuit and activate high voltage Contactors so that HV DC supply is directly fed to the Battery Pack. The Battery pack Charging is continuouslty monitored by Battery Management System (BMS). The Main opeation of BMS is to  monitor and protect the Lithium Ion battery packs. It continuously monitors the individual cell voltages. The Promary Function of BMS is Over and Under Voltage protection, Thermal Protection, Over Current protection, State of Charge(SOC) Calculation, Cell balancing, Fault detection, Maximize the Life Span. The DC voltage from Battery pack is splitted through power splitter device and is suplied to DC-DC Converter. There are two types of DC-DC Converter used in EV. The Step Down Converter is used to step down Battery pack voltage to low voltage ie12V which is used by Auxilary loads such as Headlights, Tail Lights, Indicator Lights, etc. The High Volatge DC from Battery Pack is stepped up with the help of Step Up Converter to supplt to the 3 Phase Induction Motor or Synchronous Motor. The Inverter Converts the HV DC to AC Voltage which is then supplied to Traction Motor. The Inverter acts as an Motor Controller since in many EV the Inverter and Motor Controller are integrated to control the Speed of Motor. According to the Accelerator pedal input from driver the motor controller generates the duty cycle and PWM signal is generated which controls the speed of the motor. The Motor is connected to CVT or Single Speed Transmission and the transmission output is given to the wheels through differential.

The Electric Vehicle is Charged through Electric Vehicle Supply Equipment (EVSE). Depending upon the Type of Chargng level the charging time varies. There are three levels of Charging EV.

(a) Level 1 Charging: (Home Charging)

• It uses 120V plug and standard Outlet.
• Time required to charge the battery is about 18hours to 24hours and depending onnthe battery pack capacity.
• Connectors Used: J1772, Tesla
  Charging Speed: 3 to 5 Miles Per Hour
  Locations: Home, Workplace & Public

(b) Level 2 Charging: 

• Level 2 charging is the most commonly used level for daily EV charging. Level 2 charging equipment can be installed at home, at the workplace, as well as in public locations like shopping plazas, train stations and other destinations.
• Level 2 charging can replenish between 12 and 80 miles of range per hour, depending on the power output of the Level 2 charger, and the vehicle’s maximum charge rate.
• Connectors Used: J1772, Tesla
  Charging Speed: 12 to 80 Miles Per Hour

(c) Level 3 Charging:

• Level 3 charging is the fastest type of charging available and can recharge an EV at a rate of 3 to 20 miles of range per minute.
• It is also called as DC fast Charging.
• Unlike Level 1 and Level 2 charging that uses alternating current (AC), Level 3 charging uses direct current (DC). The voltage is also much higher than Level 1 & 2 charging.
• It can charge Electric Vehicles battery from 20% to 80% in about 30 minutes.
• Connectors Used: Combined Charging System (Combo), CHAdeMO & Tesla
  Charging Speed: 3 to 20 Miles Per Minute

Types of Electric Vehicles:

There are a few different types of electric vehicles (EV). Some run purely on electricity, these are called pure electric vehicles. And some can also be run on petrol or diesel, these are called hybrid electric vehicles.

• Plug-in electric - Plug-in Electric is called as BEV which purely runs on electricity and can be charged through external supply.
• Plug-in hybrid - These cars mainly run on electricity but also have a traditional Internal Combustion Engine so the vehicle can use petrol or diesel too if they run out of charge. When running on fuel, these cars will produce emissions but when they're running on electricity, they won't. Plug-in hybrids can be plugged into an electricity source to recharge their battery or they can be charged through ICE also.
• Hybrid-electric - These run mainly on fuel like petrol or diesel but also have an electric battery too, but the capacity of battery pack is les as compared to Plug in Hybrid and BEV. This battery is recharged through regenerative braking and ICE. Based on the architecture there are Series Hybrid, Parallel Hybrid and Series-Parallel hybrid. Based on there Controller unit these vehicles switch from ICE to Electric Motor and vice versa.

                                                 Configuration of Electric Vehicle

 

Components of Electric Vehicle:

1. TRACTION BATTERY:

• An EV traction battery is rechargeable energy storage that supplies power to the electric motor very quickly, giving EVs high performance & rapid acceleration.
• Prevoiusly for EV Batteries Nickel Metal Hydride, Lead Acid, Nickel Cadmium batteries were used but due to advancement in battery technology Lithium Ion batteries are used in Electric Vehicles.
• The Lithium Ion Batteries have High Specific Energy, High Specific Power, less Self Discharge Rate, high nominal cell voltage and highe number of life cycles.
• These batteries can be charged at higher C rate and with proper thermal management system they are best for EV applications. The different types of Cell Chemistries used are NMC,NCA, LTO and Lithium Ion Poshpate.
• These cells can be manufactured in different types of form factors such as Cylindrical, Prismatic and Pouch. Mostly for EV Cylindrical cells are used because they are easy to manufacture.
• The cells are connected in ether series   or parallel to form modules and these modules are further interconnected and enclosed in a casing to form a battery pack.
• The Battery Pack Capacity is measured in KWh. The higher the KWh rating the Higher Range the Vehicle will give.

 

(2) Battery Management System:

Battery management systems (BMS) are electronic control circuits that monitor and regulate the charging and discharge of batteries. The battery characteristics to be monitored include the detection of battery type, voltages, temperature, capacity, state of charge, power consumption, remaining operating time, charging cycles, and some more characteristics.

 

(3) TRACTION MOTOR:

• The Electric Motor uses receives power from the battery pack to propel the Vehicle.
• The Motor Rating is measured in KW. Electric motors can deliver Higher Torque at zero RPM and can accelerate quickly. 
• This means that the performance of a vehicle with a 100 kW electric motor exceeds that of a vehicle with a 100 kW internal combustion engine, which can only deliver its maximum torque within a limited range of engine speed.
• The motors used for EV are BLDC Motor, 3Phase AC Induction Motor, Permanent Magnet Synchronous Motors. These motors can deliver max torque at different range of RPM.
• These motors also works as generator when brakes are applied and convert the kinetic energy generated during braking into electrical energy and recharge the battery pack through Regenerative Braking.
• The Electric Motors has efficiency between 80% to 93% depending on the type of motor used.

 

(4) Motor Controller:

• It is a device which improves the performance of an electric motor. It is a machine that is used to regulate the torque generated by the motors of electric vehicles.
• It acts as a bridge between Battery and Motor to control the speed.
• It does so by means of modifying the energy flow from the power sources to the motor. Motor controllers can include an automatic or manual means for starting or stopping the motor.
• It can choose forward or reverse rotation, can select and control the speed, can modify or limit the torque of the EV motor.
• Motor Controller has MicroController which repeatedly detects the error rectifies it and sends the proper output power.
• Hall Sensors inside the PMSM and BLDC Motors detect the position of rotor and it feds tis data to motor controller and depending on that Motor controller generates the Duty Cycle and PWM signal is generated which is given to power semiconductor switches and it controls the speed of motor as per the accelerator pedal input.

 

POWER CONVERTER UNIT:

(1) INVERTER:

• An Inverter is used to Convert the DC supply of Battery into AC Supply which is fed to electric motor to control the sped of motor.
• The inverter is also called as motor controller since in many EVs motor Controller and Inverter are integrated in a common enclosure.
• Inverter have high efficiency because the range of vehilce depends upon how effectively and efficiently the inverter converts the power.

(2) DC-DC Converter:

• DC-DC Converter is used to convert fixed DC into variable DC. There are 2 types of DC-DC converter Step-up and Step-down converter.
• Step-up Converter is used to step up the battery pack voltage to the voltage level of Motor used in EV.
• Step down converter is used to step down the high dc voltage from battery pack tom low voltage dc 12V or 24V which is used to run the auxilary load such as Head lights, Tails lights , indicator lights, Infotainment systems etc.

 

(3) On Board charger (Rectifier Circuit):

• The On board charger consists of a Rectifier circuit which converts the AC supply to DC Supply. This charger is installed inside the vehicle.
• The On board charger not only converts the AC to DC but it has to step the the DC voltage to the voltage which is required by battery pack.
• When Fast Charging DC supply is applied so On board charger detects it and by passes the Rectifier circuit and sends dc supply directly to the battery.

 

VEHICLE PARAMETERS:

Parameters	Values
Vehicle Kerb Weight	1400Kg
Vehicle Dimensions (L*B*H)	3994*1811*1606mm
Tyre Size	215/60/R16
Radious of tyre in m	0.33m
Frontal Area	2.6176`m^2`
Drag Coefficient	0.25
Coefficient of Rolling Resistance	0.022
Battery Pack Capacity	320V, 30.2KWH
Motor Rating	320V, 93.4KW
Motor Peak Torque	245Nm
Gear Ratio	11

 

                                                Block Diagram of EV

1. Drive Cycle: It is used to input the data into the driver controller.
2. Driver Controller: It controls the Acceleration and Deceleration of the vehicle.
3. Power Converter: It consists of PWM generator and H-Bridge with Regenerative Braking. The Drive Cycle Acceleration and Deceleration commands are given to PWM generator and PWM generator generates PWM signal whicg is given to H-Bridge which is used to drive the DC Motor.
4. Battery: It indicates the charge and discharge condition and the % SOC (State of Charge) variations with respect to the drive cycle.
5. Motor: It generates the required power to propel the vehicle.
6. Vehicle Body: It indicates the mechanical structure of an EV with Gear and Tyres.

 

SIMULINK MODEL:

 

 The simulink Model of Electric Vehicle is constructed using 4 blocks:

1. Vehicle Body Subsystem

2. Motor & Motor Controller

3.Battery Pack Subsystem

4.Driver Subsystem

 

1. Vehicle Body Subsystem:

The Vehicle Body Subsystem consists of Vehicle Body, Magic Tire and Simple gear. The Vehicle body consists of Vehicle Mass, Aerodynamic Drag Coefficient, Number of wheels per axle, Frontal Area, Air Density and Center of Gravity.

Input Ports:

W = Wind Velocity in m/s

beta = Grade angle in Radians

Output ports:

V = Velocity in m/s

NR = Normal force on Rear Axle (N)

NF = Normal Force on Front Axle (N)

1.1 VEHICLE BODY:

• The Vehicle Body Represents a two-axle vehicle body in longitudinal motion. The block accounts for body mass, 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. Optionally include pitch and suspension dynamics or additional variable mass and inertia. The vehicle does not move vertically relative to the ground.
• Connection H is the mechanical translational conserving port associated with the horizontal motion of the vehicle body. The resulting traction motion developed by tires should be connected to this port.
• Connections V, NF, and NR are physical signal output ports for vehicle velocity and front and rear normal wheel forces, respectively. Wheel forces are considered positive if acting downwards.
• Connections W and beta are physical signal input ports corresponding to headwind speed and road inclination angle, respectively. If variable mass is modeled, the physical signal input ports CG and M are exposed.
• CG accepts a two- element vector representing the x and y distance offsets from vehicle CG to additional load mass CG. M represents the additional mass. If both variable mass and pitch dynamics are included, the physical signal port J accepts the inertia of the additional mass about its own CG.
• Below are the vehicle body parameters selected for Vehicle model

 

1.2 TIRE (MAGIC FORMULA):

• Represents the longitudinal behavior of a highway tire characterized by the tire Magic Formula. The block is built from Tire-Road Interaction (Magic Formula) and Simscape Foundation Library Wheel and Axle blocks. Optionally, the effects of tire inertia, stiffness, and damping can be included.

• Connection A is the mechanical rotational conserving port for the wheel axle. Connection H is the mechanical translational conserving port for the wheel hub through which the thrust developed by the tire is applied to the vehicle. Connection N is a physical signal input port that applies the normal force acting on the tire.

• The force is considered positive if it acts downwards. Connection S is a physical signal output port that reports the tire slip. Optionally expose physical signal port M by setting Parameterize by to Physical signal Magic Formula coefficients. Physical signal port M accepts a four element vector corresponding to the B, C, D, and E Magic Formula coefficients.

• The Vehicle is Rear Driven 2 wheels per axle (4Wheels).

 

• The tires are parameterized by Peak longitudinal force and corresponding slip
• The other block parameters such as rated vertical load, peak longitudinal force at rated load and slip at peak force at rated load - are kept with their default values.

 

1.3 SIMPLE GEAR:

• Simple Gear represents a fixed-ratio gear or gear box. No inertia or compliance is modeled in this block. Simple Gear is used to connect the Motor output to Vehicle Rear Axle. It Transfers the Motor Output Power to the wheels.

• Conserving Ports:

  B = port associated with an input shaft (motor shaft)

  F = port associated with the output shaft (axle/ differential)

   

• Gear ratio and output direction are modified. Meshing loss is kept constant and gear is having a constant efficiency throughout the simulation.

• Viscous losses and faults are kept at default conditions.

 

2. MOTOR & MOTOR CONTROLLER SUBSYTEM:

The Motor Controller has input of Acceleration and Deceleration Command from driver block. Contrlled Voltage Source are used to connect the Acceleration and deceleration to Controlled PWM voltage and H-Bridge Brake. The PWM generates the PWM gate signal at 5000Hz whih is given to H-bridge. The H-Brige acts as motor controller which opeartes in 4 quadrant to control the speed of DC Motor. The H-Bridge output +ve trermonal is connected to +ve terminal of DC Motor and -ve terminal of H-bridge, DC Motor PWM are grounded by using Electrical Reference. An Ideal Rotational Motion Sensor is used to measure the Motor RPM. The Motor Output is connected to Vehicle Body Subsystem through Simple Gear. The PWM +ve termonal is connected to the battery pack subsytem through Current Sensor. Voltage Sensor is used to measure the Voltage of Motor and Motor Voltage and Current are multiplied to calculate motor power. 

2.1 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 constants have the same numerical value when in SI 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 parameter can be set to some small non-zero value.When a positive current flows from the 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 back-emf or torque constants.
• + = Electrical signal to the motor Positive Terminal
• - = Electrical signal to the motor Negative Terminal
• R = Casing of the Motor connected with the Mechanical Rotational Reference Block
• C = Rotor Case connected to the Mechanical Rotational reference
• The DC Motor parameters are 320V 93.4KW, Rated Speed 3640RPM. All other parameters are kept default. 

 

2.2 H-BRIDGE:

The H-Bridge is used to control the Speed of DC Motor depending upon the PWM signal received from Controlled PWM. The H-Bridge input ports has PWM signal, Reference signal, REV and Braking. The H-Bridge has setting that during Braking it can regenerate the energy through regenerative braking and charge the battery pack.

The H-Bridge has 5V PWM signal amplitude and it generates 320V DC Supply at ouptut which is connected to DC Motor.

 

2.3 CONTROLLED PWM VOLTAGE:

• This block creates a Pulse-Width Modulated (PWM) voltage across the PWM and REF ports. The output voltage is zero when the pulse is low, and is equal to the Output voltage amplitude parameter when high.
• The Duty cycle is adjusted as per the input received from Driver Block ie Drive Cycle.
• 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 with value equal to the averaged PWM signal.
• The PWM frequency is set to 5000Hz.
• At +ref Acceleration command from Drive Cycle is connected.
• At -ref Deceleration command from Drive Cycle is connected. 
• PWM and REF are directly connected to H-Bridge. Rest of the parametrs are kept default.

2.4. CONTROLLED VOLTAGE SOURCE:

• The Controlled Voltage Source block converts a Simulink input signal into an equivalent voltage source.
• In steady state, the Simulink input must be connected to a signal that begins the simulation as a sinusoidal or DC waveform that corresponds to the initial values.
• In above model, 2 Controlled Voltage Source blocks are used, the positive terminal is connceted to the positive reference terminal of the Controlled PWM Voltage block and the negative terminal is connected to the Common Ground.
• -Negative terminal is connected to the Input Port 1which indicates the Acceleration.
• The other block, the positive terminal is connected to the Break Port of H-Bridge block and the negative terminal is connected to the common ground.Physical port is connected to the Input Port 2 which indicates the Deceleration.

2.5 CURRENT SENSOR:

• The Current Sensor is used to measure or sense the current flowing through any device. The Current source is connected in series between 2 blocks.
• The positive and the negative terminals are connected between the H-Bridge and the DC Motor. Connection I is the physical signal output port for the measurement of result current.

2.6 VOLTAGE SENSOR: 

• The Voltage Sensor block indicates an ideal voltage sensor,i.e., a device that converts voltage measured across the motor into a physical signal proportional to the voltage.
• The positive and the negative ports are technical conserving ports through which the sensor is connected to the circuit.V port is the physical signal port that measures the result of voltage across the motor.

 

2.7 PS-SIMULINK CONVERTER:

• The PS-Simulink Convereter is used to convert the input Physical Signal to a Simulink output signal. When Simscape Blocks are used the ouput of these blocks cannot be directly connected to the simulink blocks. 

2.8 Electrical Reference:

 

• The Electrical Reference block represents an electrical ground.
• Electrical conserving ports of all the blocks that are directly connected to ground must be connected to an Electrical Reference block. 

 

3. BATTERY PACK SUBSYSTEM:

The Battery Pack subsystem consists of battery block, controlled controlled source, Power gui Block and Bus selector. the Controlled Current Source receives signal from H-Bridge which is cuurent and these blockm is connecetd to battery block.

3.1 BATTERY:

• The Battery block Implements a generic battery model for most popular battery types.

• The Battery Pack capacity for Simulink Moel is 320V 30.2KWH. Rest all the parameters are kept constant.

3.2 CONTROLLED CURRENT SOURCE:

• The Controlled Current Souce block represents an Ideal Current Source that is powerful enough to maintain the specified current through it regardless of the voltage accross the source.
• This block is connected across the Battery.

3.3 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.

• By using the Up, Down, or Remove button to reorder the selections. Check 'Output as virtual bus' to output a single bus.

 

3.4 POWER GUI BLOCK:

• The powergui block allows you to choose one of these methods to solve your circuit.
• Continuous, which uses a variable-step solver from Simulink.
• Discretization of the electrical system for a solution at fixed time steps.Continuous or discrete phasor solution.

4. DRIVER BLOCK:

The Driver Subsystem consists of Drive Cycle Source, Multiport switch, longitudinal Driver block. The Longitudinal driver block receives input from multiport switch. The Drive Cycle source is connected to multiport switch. the longitudinal driver generates the acceleration and deceleration command as per the drive cycle. It has input from the vehicle body sdystem called as feedback velocity.

4.1 DRIVE CYCLE SOURCE:

The Drive Cycle Source generates a standard or user-specified longitudinal drive cycle. A drive cycle is typically represented by a series of data points which plots vehicle speed against time. Driving cycles are produced to assess the performance of vehicles in various ways, including fuel consumption and pollutant emissions. In EV drive cycle is used to find out the Energy Consumption, Range.

In above Model 2 Drive Cycles are used:

1. Modified Indian Driving Cycle(MIDC)

The Drive Cycle is has run time of 400seconds. At the end of drive cycle the distance covered is 6.505Km. The max speed is 90kmph. This drive cycle is used for Indian Conditions to estimate tail pipe emission, Energy Consumption and to estimate the range.

 

2. Urban Dynamometer Driving Schedule (UDDS):

The EPA Urban Dynamometer Driving Schedule (UDDS) is commonly called the "LA4" or "the city test" and represents city driving conditions. It is used for light duty vehicle testing. The Drive Cycle max speed is 90kmph and is run for 1369seconds. The distance covered is 11.98km ~12km. 

 

4.2 LONGITUDINAL DRIVER:

• The longitudinal Driver is an inbuilt block provided by the powertrain blocks.
• It is a parametric longitudinal speed tracking controller for generating normalized Acceleration and Braking commands based on reference and feedback velocities,
• The VelFdbk port corresponds to the feedback velocity. The actual velocity output given by the vehicle body is connected here. By comparing the actual (feedback) velocity with the reference velocity, the driver block generates acceleration and braking signals in order to minimise the error between the two concerned velocities.
• Grade corresponds to the grade angle. For this simulation, no inclination is considered and hence, a constant block with value 0 is connected.
• Info gives the output for the bus signal for different block calculations like the difference in reference vehicle speed and vehicle speed, etc.
• AccelCmd & DecelCmd correspond to the acceleration and deceleration commands generated respectively and are connected to the corresponding ports of the Controlled PWM Voltage block Here, the selected control type is Pl. Accordingly, the block implements proportional-integral (PI) control with tracking windup and feed-forward gains.

4.3 MULTIPORT SWITCH:

The Multiport Switch  determines which of several inputs to the block passes to the output. The block passes this based on the decision of value of the first input. The first input port  is the control input and the remaining inputs are the data inputs.

 

5. DISTANCE CALCULATOR SUBSYSTEM:

The Feedback velocity fromm Vehicle body block is integrated and divided by 3600 to get the distance covered by vehicle in Km. The Drive Cycle and Vehicle Feedback Velocity is compares and is displayed in Scope.

6. ENERGY CONSUMPTION:

The above subsystem helps to determine the Energy Consumption (Wh/km) approximately. The Motor Power is given as input and a gain block which refers to Inverter and converter efficiency is integrated. The Value found is in Joules so it is futher divided by `3.6*10^6` to convert Joules to KWH. The KWH is divided by Drive Cycle Distance Distance Covered in one cycle to get Wh/Km Consumption.

 

SIMULATION MODEL EXPLANATION:

• The First block is a driver Subsytem which has Drive Cycle input. 2 Drive Cycles are used for above model MIDC and UDDS. The Drive cycle input is given to Longitudinal Driver Model through Multiport Switch.
• The Longitudinal Driver is used to control all of the inputs and it generates the Acceleration and Deceleration command.
• These commands are given to the Motor Controller block which consists of PWM block, HBridge and DC Motor. A Voltage controlled block is used to convert the Simulink input signal into an equivalent voltage source.
• The PWM generator has a switching frequency of 5000Hz and PWM amplitude of 5. The duty cycle varies from 0 to 1.
• The PWM signal generated is given to H-Bridge which generates a 320V of DC Supply which is given to DC Motor.
• The DC Motor rating is 320V 93.4KW. The Rated RPM is 3640 and No load RPM of 8000.
• The Current sensor block is used to measure the current flowing from the DC Motor and this current is given as input to Battery Subsystem. 
• The Battery selected is Li-Ion which has Capacity of 320V 30.2KWH. The Battery Pack Subsystem calcutaes Battery SOC, Curent and Voltage.
• The DC Motor Output is given to Simple Gear which has Gear Ratio of 11 and it is connected to Rear Axle of Vehicle Body.
• The Vehicle mass is 1400Kg and is rear wheel drive. The Vehicle Body block calculates the vehicle velocity which is given as feedback to Longitudinal Driver and the Drive Cycle Speed and Actual Vehicle Speed are compared.
• The Scope block is used to display the Graph. The Vehicle Velcoity is integrated and divided by 3600 to find the distance covered in Km.
• The Motor Power is given as input to Energy Consumption block to calculate the Wh/Km consumption.

 

SIMULATION RESULTS:

CASE 1: MIDC DRIVE CYCLE

a. Drive Cylce Plot

• The above graph compares the Drive Cycle speed with actual  vehicle speed.
• The Yellow graph represents Drive cycle and blue graph represents Actual Vehice Velocity.
• The actual vehicle velocity follows the drive cycle velocity for maximum period but at the end of the cycle the velocity is limited to 85kmph.

 

b. Motor RPM Plot:

• The above graph shows the variation of Motor RPM wrt Drive Cycle.
• The Motor has Max RPM of 7500 and motor RPM varies between 4500 to 7500.

c. Battery SOC plot:

• The above graph representsbthe Battery State of Charge(SOC).
• The SOC is at 100% at the start of simulation and is reduced to 96.16% after 400seconds.
• At start since vehicle is at rest the SOC is at 100% then as the vehicle accelerates the SOC starts to drop but whenever brakes are applied then due to regenerative braking the Motor operates as generator and Charges the Battery. Whenever brakes are applied the SOC increases.
• At the end of Drive cycle the SOC increases significantly since vehicle speed is reduced from 90kmph to 0kmph.

d. Battery Current plot:

• The above plot shows variation of Battery Current when vehicle runs. At start the the battery discharges at 110A since vehicle is accelerating from rest.
• The Battery current from varies from 110A to -110A. The current is stable whenever vehicle is at constant speed.
• At end of the graph the negative graph represents the battery is charging due to regenrative braking.

e. Battery Voltage plot:

• The above plots shows the Battery voltage graph. The battery used is of 320V so its max voltage at 100% SOC is 372V.
• The battery voltage decreases at the time of acceleration and there are certain spikes which occurs when vehicle is decelerating.
• At the end the voltage increases from 346V to 369V.

f. Distance Covered Plot:

• The above plot shows the distance covered by vehicle in MIDC Drive cycle. The Vehicle covers a distance of 6.50Km in 400seconds.

g. Wh/Km Consumption Plot:

• The above plot shows the Energy consumption of Electric vehicle during MIDC Drive cycle.
• The Energy consumption ie Wh/Km Consumption is the energy consumed by the vehicle per km from battery pack.
• For MIDC Wh/Km Consumption is 155.3. The Wh/Km Consumption varies depending upon the Motor and Power converter efficiency as well as the gear ratio selected and its efficiency.

 

Range of Vehicle by using MIDC:

Battery Capacity = 320V, 94.375Ah, 30.2KWH

Wh/Km Consumption = 155.3

Vehicle Range = `(Bat tery Capacity)/((Wh)/(Km)Consmption`

Vehicle Range = `(30200)/155.3`

Vehicle Range = 195Km

 

CASE 2: UDDS DRIVE CYCLE

a. Drive Cycle:

• The above graph compares the Drive Cycle speed with actual vehicle speed.
• The Yellow graph represents Drive cycle and blue graph represents Actual Vehice Velocity.
• The actual vehicle velocity  and Drive cycle curve are overlapping indicating that parameters selected for motor are able to produce peak power as per drive cycle.

b. Motor RPM Plot:

• The Motor RPM is following the Drive curve and motor produces peak RPM of 7500. The motor has average RPM of 4500.

c. Battery SOC plot:

• The above plot shows Battery SOC varying as per Drive cycle. The SOC has lot of variatons because drive cycle has continuous acceleration and deceleration for 1369seconds.
• During deceleration the Battery SOC increases. At the end of drive cycle the battery SOC is reduced from 100% to 89.08%.

d. Battery Current plot:

• The above plot shows Battery Current variation as per the drive cycle.
• The battery current varies from 170A to -140A as vehicle accelerates and decelerates. The -ve current indicates the battery being charged due  to regenerative braking.
• The average current consumption is between 70A to 80A.

e. Battery Voltage plot:

• The above plot shows variation of battery voltage wrt drive cycle acceleration and deceleration.
• At the end of drive cycle the battery voltage is reduced from 372V to 350V.

f. Energy Consumption:

• The above plot shows the Wh/km consumption of UDDS drive cycle. The Vehicle consumes about 167Wh for travelling 1Km.
• Since UDDS has high power consumption as speed is varying continuously as compared to MIDC so Wh/Km consumption has increased.

g. Distance Covered:

• The above plot shows the distance covered by vehicle for UDDS Drive Cycle.
• The Vehicle covers 12Km after 1369seconds.

Range of Vehicle by using UDDS:

Battery Capacity = 320V, 94.375Ah, 30.2KWH

Wh/Km Consumption = 167

Vehicle Range = `(Bat tery Capacity)/((Wh)/(Km)Consmption`

Vehicle Range = `(30200)/167`

Vehicle Range = 181km

 

Parameters	MIDC Drive Cyle	UDDS Drive Cycle
Drive Cyle Run Time in Seconds	400	1369
DistanceTravelled in Km	6.505	12
Wh/Km Consumption	155.3	167
SOC Remaining in %	96.16	89.08
Max Velocity (kmph)	85	85
Battery Voltage	348.6	349.3
Vehicle Estimated Range in Km	195	181

 

CONCLUSION:

• The Simulink Model of an Electric Vehicle is created by using DC Motor and  Battery block and it is simulated by using 2 Drive Cycles MIDC and UDDS and results have been plotted and explained.
• The  Model helps to determine the Vehicle Velocity, SOC, Range of Vehicle and Wh/Km Consumption for both the Drive Cycles.
• A table is plotted to compare both the drive cycle results.