Final Project: Design of an Electric Vehicle

Final project:

Create a MATLAB model of electric car which uses lithium ion battery and induction 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

Introduction

The current transportation sector is fully occupied with IC engine vehicle. The conventional IC engine vehicle uses fossil fuel as source for propulsion. So the amount of fossil fuel consumed has reached its maximum capacity but the resources for fossil fuels starts declining. Meanwhile due to increase in population the energy demand is also increased. In order to meet these challenges electric –mobility comes into picture. But for a sustainable future, this sector is shifted drastically towards electrical mobility. Therefore Electrical vehicles (EV) are marking a revolution all around the world because of their environmental and socio-economical advantages. EVs invade the transportation sector at the side of economical and user-preferred updates.

It is considered to be the best alternative solution for reducing pollution and emission which promote eco-friendly transportation for the countries. Many smart city projects are implemented with electrification of electric vehicles in India.

The future engineers reply on electric mobility since the potential of electrification is huge and it can bring significant changes in the mobility sector and creates lot of job opportunities and promotes business, starting from electrical vehicle design, manufacturing, automation ,electrical grid and, charging infrastructure. Various opportunities exists related to electro-mobility, to identify charging stations, vehicle-to-vehicle communication, Vehicle tp grid technologies, integration of renewable sources and other service in establishing smart city projects.

The electric vehicle is basically a vehicle that operates on portable energy sources like battery and traction effort provided by the motor(AC/DC). Most induction motors are used here. Unlike ICE engine powered vehicles, these EVs do not produce harmful emissions which becomes eco-friendly mode of transportation.

However the electrical energy required for charging the vehicle can be produced from renewable sources as well like solar,wind,hydroelectric or bio-gas.

EVs are classified into main categories like AEVs and PHEVs.

AEVs (all-electric vehicles) are powered by the electric motors. The electricity is provided by the grid and store it in batteries. They consume no fuel and produce no harmful emissions. It entirely run only on electricity. It includes Battery Electric Vehicles (BEVs) and Fuel cell Electric Vehicles(FCEVs) Where as in PHEVs (plug-in hybrid electric vehicles) use batteries to power an electric motor and plugs into the electric grid for charging and it also uses an alternative fuel to power the internal combustion engine in case of emergency situations.

Why EV ?

The operation of electric drive motors runs quieter than internal-combustion engines. The noise emissions from electric vehicles is very low.

Electric vehicles produce zero tailpipe emissions, fewer greenhouse gases and other harmful air emissions than traditional gas-powered cars during mobility. If the high-voltage battery of electric vehicle is charged from renewable energy sources then EV becomes more eco-friendly without the emission of greenhouse gases.

Traditional internal combustion engines have dozens of moving parts, with maintenance costs that add up over time. but electric vehicles require far less ongoing maintenance than gas cars. Because these vehicles contain fewer moving parts, there are simply fewer chances that a given component will wear out.

The power drive train design is simple because vehicle components like the transmission, clutch, mufflers, particulate filters, fuel tank, starter, alternator and spark plugs are not required for electric vehicle.

Electric drive motors exhibits excellent torque and output characteristics. It develops maximum torque from standstill condition. This allows an electric vehicle to accelerate considerably faster than a conventional vehicle with an IC engine producing the same output.

Electric drive motors have a highest efficiency of up to 96% compared with internal-combustion engines which has an efficiency of 35–40% range.

When the vehicle is brake mode, the motor can also be used as an alternator that produces electricity and charges the battery (regenerative braking).

EV charging stations are easier to find using Google maps and other charging station locator applications.

The advancement in the battery technology have rapidly developed. The U.S. Department of Energy reports that batteries in every new EVs are designed to last for the expected lifetime of the vehicle. Batteries do wear out so replacement batteries will eventually be needed. Most car manufacturers warrant EV batteries for around 8 years.

Electric vehicles can help to increase our transportation fuel independence which means EV drivers can produce some or all of the energy needs for their vehicles using renewable sources which promotes energy independence.

Electric vehicles are energy efficient, time efficient, and cheaper over the life of the vehicle, making them a practical solution and perfect replacement to conventional IC engine vehicles.

Disadvantages of Electric Vehicles

The Initial Investment for electric vehicle is Steep and undesirable compared with conventional IC engine vehicles.

The network of electric charging stations is sparse. Electric fuelling stations are still in the development stages. It may be harder to find a charging station in sub-urban and rural areas.

Electric vehicles have a limited range due to battery size and capacity.

The charging time of battery depending on the battery charge and power source exhibits long duration. an electric car takes about 4-6 hours and sometimes even a day to get fully charged. There are some kits that can cut the charging time down. But again, that is going to be an additional investment.

Depending on the type and usage of battery, batteries of almost all electric cars are required to be changed every 3-10 years.

At the same time, the vast amount of customization is available with traditional cars. But in EVs Fewer options to customize,analyse and choose the desired aesthetics of your EV.

This diagram gives us some idea about the basic connections and energy conversion from electrical to mechanical energy with these components.

A matlab model is simulated with powertrain blocksets and other component level blocks.

The main components and requirements in the EV like Battery, motors, controller circuit, power converters, Transmission system and wheel, tire and axles.

Lithium-ion batteries have higher specific energy relative to the other battery types. In the future, technology innovations with Li-ion and other battery technologies are expected to result in batteries with much higher specific energy and lower costs.

A controller is the main part of controlling and managing the parameters in the system. It controls the rate of charge using information from the battery. It also translates pressure on the accelerator pedal to adjust speed in the motor inverter.

The main components of a vehicle which convert the engine-generated power to movement, are called powertrain.The computerized system that uses the powertrain components is known as the control system of powertrain.

Under the system-level configuration, the vehicle body is modeled. Under the subsystem of vehicle body the gear, transmission, shaft, tires components are used. The vehicle is subjected to some wind velocity and road inclination on normal roads is not preferred. And the velocity is converted into km/hr. The front and rear tires are separately noted. R is the nothing but the input given to the system from the motor shaft and V is the velocity in km/hr.

For the motor application induction or DC motor can be used. But DC motor has fewer parameters which is easy to control. Point R from the motor is given as input to the vehicle body block.

An Inverter circuit will be required in the case of AC motor. An inverter is a device that converts DC power to the AC power used in an electric vehicle motor. The inverter can change the speed at which the motor rotates by adjusting the frequency of the alternating current. It can also increase or decrease the power or torque of the motor by adjusting the amplitude of the signal.

Power converter is used to provide signals and input given by DC motor required for motion of vehicle. And a controlled PWM block is used to provide a controllable pulse with modulated voltage to the H bridge block. The pulses dependent on the duty cycle is set by input of PWM voltage block. A controllable voltage source is used to provide voltage pulses required for H-bridge converter.

The longitudinal block requires the data of input drive cycle and the velocity of feedback from the final V of vehicle body and Acceleration and deceleration command is given for controllable voltage source as input to operate the converter and PWM voltage block. And the grade value is 0 for linear normal road conditions without slope.

A drive cycle has velocity and time data required for the motion of vehicle.The FTP75 cycle is used here and simulated for the 2500s.

A battery circuit is modeled in order to obtain the SOC characteristics.

The battery current is viewed through scope and final SOC % is obtained.

Results

The velocity values of the reference FTP75 and velocity in the feedback is shown in the plot using scope.

Battery SOC % values decreases with time. The plot shows the battery SOC values with respect to time. SOC depends on the battery current,speed and range of vehicle travelled.

Current plot is shown in the figure

The system is modeled with system parameters and powertrain blocksets. And the EV model is simulated and results are obtained in the output scope for different components and parameters.

By unlocking the full flexibility of electric vehicles through dynamic controlled charging (V1G) and vehicle-to-grid services (V2G) to cope with the variable renewable energy generation and thereby to reduce electricity generation capacity. It would require the adaptation of regulatory and market frameworks which makes electric vehicles more efficient and desirable for users.