Week 8 Challenge

(W8) Challenge

AIM :- Model energy storage device as ultracapacitor and analysis and its operating characteristics

Blocks Used :- constant, integrator, saturation, terminator, memory, add, product, signal builder, sqrt, scope.

Ultracapacitors are energy storage devices that have higher power density and faster charging and discharging capabilities compared to traditional batteries. The modeling and simulation of ultracapacitors involve considering the electrical and electrochemical characteristics of the device.

One common way to model ultracapacitors is by using an equivalent circuit model that represents the electrical and electrochemical behavior of the device. This model consists of a series combination of a capacitor and a resistor, representing the electrical properties of the ultracapacitor, and a parallel combination of a capacitor and a resistor, representing the electrochemical behavior of the device.

To simulate the ultracapacitor model, you would need to use a simulation tool that supports circuit modeling and analysis, such as SPICE (Simulation Program with Integrated Circuit Emphasis) or MATLAB/Simulink. In the simulation, you would apply a voltage or current to the ultracapacitor model and observe the resulting current, state of charge (SOC), and voltage of the device over time.

The simulation stop time would depend on the specific application and the desired level of accuracy in the simulation. It is important to note that the accuracy of the simulation results also depends on the accuracy of the model parameters and the assumptions made in the model.

To calculate the state of charge (SoC) of a battery, we can use a variety of methods, depending on the type of battery and the equipment you have available. Here are some common methods:

Voltage-based method: This method involves measuring the voltage of the battery and comparing it to a reference voltage. The SoC can then be estimated based on a lookup table or mathematical equation that relates voltage to SoC. However, this method may not be very accurate due to voltage fluctuations caused by temperature and load conditions.

Coulomb counting method: This method involves measuring the current flowing in and out of the battery and integrating the current over time to determine the total charge that has been delivered or received. The SoC can then be estimated by comparing the total charge to the battery's rated capacity. However, this method may not be very accurate due to variations in battery efficiency and self-discharge.

Hybrid method: This method combines voltage and coulomb counting methods to improve accuracy. The voltage-based method is used to estimate SoC when the battery is at rest, and the coulomb counting method is used when the battery is in use.

Model-based method: This method uses a mathematical model of the battery's behavior to estimate SoC based on voltage, current, temperature, and other factors. This method can be very accurate but requires detailed knowledge of the battery's characteristics and may be computationally intensive.

Ultimately, the most accurate method for calculating SoC will depend on the specific battery type and application. It is always recommended to consult the manufacturer's documentation or seek expert advice before attempting to determine the SoC of a battery.

But here for calculating the current, voltage, open circuit voltage, and charge calculation we use the mathematical method.

Now in the system characteristic can be calculate by

Procedure:

Signal builder block is used as a power demand source.

In the Ultracapacitor subsystem, current and voltage calculation subsystem and SOC calculation

In the charge and voltage calculation subsystem, the current, voltage, open circuit voltage and charge calculation subsystem is formed.

Input to the current subsystem is power demand from the signal buider and feedback from the SOC.

I = SOC*V_max – sqrt(SOC*V-max)^2 – (4*R8Puc*eff))/(2R))

The open circuit voltage = int(1/C)*dt

The charge can be calculate by Q = C*Vmax

Voltage calculation :- V = (SOC*Vmax) – (I*R)

The SOC = int(I*eff)/Q)*dt