Project-1: Modelling an electric Car with Li-ion battery
Aim :-
Modeling a electric car with lithium battery
Objective :-
Creating a electric car design with lithium ion battery by the assuming the data by ourselves and make a excel sheet data.
Introduction :-
An electric car with a lithium-ion battery typically has the following design:
Lithium-ion Battery Pack: This is the main power source for the electric car. It is made up of multiple cells connected in series and/or parallel to provide the desired voltage and current. The battery pack is usually located under the car's floor, providing a low center of gravity for better handling and stability.
Electric Motor: The electric motor is the main component that converts the energy stored in the battery pack into mechanical energy that powers the car. It is usually located in the front or rear of the car and connected to the wheels via a transmission system.
Charging Port: The charging port is where the electric car is plugged in to recharge the battery pack. It is usually located on the front or rear of the car.
Regenerative Braking System: The electric car uses regenerative braking to convert the kinetic energy produced during braking into electrical energy that can be stored in the battery pack. This system helps to improve the car's efficiency and extend its range.
Battery Management System (BMS): The BMS is responsible for monitoring the status of the battery pack, including its state of charge, temperature, and voltage. It ensures that the battery pack is used within safe operating limits and helps to extend its lifespan.
Control Electronics: The control electronics manage the flow of power between the battery pack, electric motor, and other components of the car. They also control the car's speed, acceleration, and other driving functions.
Overall, the design of an electric car with a lithium-ion battery pack is focused on maximizing efficiency, range, and performance while ensuring safety and reliability.
Designing parts :-
(a) Drive Cycle
(b) PID Controller
(c) Motor controller
(d) Vehicle Body subsystem
(e) Battery and soc subsystem
(a) Drive Cycle :-
Drive Cycle :-
A drive cycle involves a sequence of driving conditions that include a mix of urban and highway driving, different speeds, accelerations, and decelerations. The cycle may also include idling, hot and cold starts, and other variables that affect emissions and fuel consumption.
Drive cycles are used to evaluate the performance and emissions of vehicles, as well as to develop and calibrate onboard diagnostic systems (OBD) that monitor and control emissions in real-world driving conditions. They are also used to establish regulations and standards for vehicle emissions and fuel economy and here I use FTP75.
(b) PID Controller :-
A PID (Proportional-Integral-Derivative) controller is a feedback control system used in industrial processes to regulate variables such as temperature, pressure, flow rate, and level. The controller continuously measures the process variable, compares it to the desired setpoint, and adjusts the control output accordingly.
The PID controller uses three main control terms: proportional, integral, and derivative, which are combined in various ways to achieve the desired control action.
Proportional term: The proportional term is based on the current error between the process variable and the setpoint. The controller output is proportional to the error, which means that the larger the error, the larger the control action.
Integral term: The integral term is based on the accumulation of past errors over time. The controller output is proportional to the integral of the error, which means that the longer the error persists, the larger the control action.
Derivative term: The derivative term is based on the rate of change of the error over time. The controller output is proportional to the derivative of the error, which means that the faster the error is changing, the larger the control action.
The PID controller combines these three terms in different ways to achieve the desired control response. The controller parameters (proportional, integral, and derivative gains) are typically tuned manually or using an automated tuning algorithm to achieve optimal performance.
(c) Motor controller
Controlled PWM voltage signal block :-
It generates a Pulse Width Modulation (PWM) waveform with a controllable duty cycle and frequency. The block typically has inputs for the reference signal, which is the desired voltage to be generated, and a modulation index, which determines the amplitude of the PWM waveform. The block also has outputs for the PWM waveform and its complementary signal.
Ports
The PWM & REF connections are for the corresponding ports on the H-Bridge circuit.
The 2 reference inputs correspond to the throttle inputs given by the driver. The block generates corresponding pulse width as per the accelerations and brakes applied by the driver himself.
Power convertor h-bridge :-
The H-bridge Simulink block typically has inputs for the DC input voltage and a control signal that determines the duty cycle of the output waveform. The block also has outputs for the AC output voltage and current.
The H-bridge circuit consists of four switches arranged in an H-shaped configuration. By turning on and off these switches in a specific sequence, the H-bridge circuit can generate an AC output waveform with a controllable voltage and frequency.
In this project H-bridge take PWM controlled signal from control PWM voltage generator.
Battery charge and discharge :-
To model the Battery pack, a simple Battery block is used. This is because, if the generic battery block is used instead, the simulation will run for a much longer time.
Here, the selected option for Battery Charge Capacity is Finite. Accordingly, the block models the battery as a series internal resistance plus a charge-dependent voltage source.
If the chosen option had been Infinite, the voltage source would have been constant.
Also, the self-discharging of the battery and the battery dynamics are disabled.
Motor (permanent magnet DC) :-
The DC Motor block represents the electrical and torque characteristics of a DC motor using the following equivalent circuit model and its provide mechanical output.
In this project we use rated PM-DC motor speed at no load is 8000rpm and at load condition 5000
Battery state of charge :-
State of charge (SoC) refers to the amount of electrical energy that is currently stored in a battery or other energy storage system, expressed as a percentage of its total capacity. It indicates how much of the battery's available energy has been used and how much remains. For example, a battery that is fully charged has a SoC of 100%, while a battery that is completely discharged has a SoC of 0%. SoC is an important parameter to monitor when using batteries, as it can affect the battery's performance and lifespan.
SOC = (Q/Qmax) x 100%
Solver Configuration :-
A Solver Configuration is added to ensure proper solving of the mathematical equations by the model.
Vehicle body :-
The block typically has inputs for the external forces and torques acting on the body, such as those from the wheels, suspension, and aerodynamic effects. It also has outputs for the position, velocity, and orientation of the body, which can be used to connect to other blocks in the simulation.
The Vehicle Body block can be useful for simulating vehicle dynamics and evaluating the performance of different suspension and control systems.
This 2 axle (4 wheel) assembly is now connected to a Velocity Body Simscape block.
This block basically represents a two-axle vehicle body in longitudinal motion. The block accounts for -
body mass,
aerodynamic drag,
road incline,
weight distribution between axles due to acceleration
road profile.
Here, the connection H is the mechanical translational conserving port hub.
NF & NR correspond to the output ports for normal reaction forces on front axle and rear axle wheels respectively.
Connection V represents the actual output translational velocity of the vehicle.
beta is the road inclination angle & W corresponds to the headwind speed (headwind - direction opposite to that of vehicle).
And the specified parameters are shown in the pic.
Tire
The wheels are modelled using simple Tire (Magic formula) simulink blocks.
The N port of the tire corresponds to the Normal Reaction acting on it.
The A port corresponds to the Mechanical Rotational conserving port for the wheel axle. Thus both the wheels on the same axle should form a connection through their respective A ports.
Connection H corresponds to the Mechanical Translational conserving port for the wheel hub through which the thrust developed by the tire is applied to the vehicle. Thus, all the 4 wheels form a connection through their respective H ports and this is in turn connected to the translational hub of the vehicle body.
The connection S represents the output port for slip of the tire.
Output of the system :-
It show the constant voltage after modulated voltage and constant speed of the system and state of charge of the vehicle is 20% of intitial and 100 % is maximun here I used ftp drive cycle we can see in the output and average energy consumption is constant is showing in this image and vehicle velocity is constant.