Week 8 Challenge

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About Ultracapacitor:-

An Ultracapacitor also known as a supercapacitor or electrochemical capacitor is a device for storing electrical enegry which is growing radpidly in popularity The design and mechanism of operation is somewheer between and ordinary capacitor and a battery which open up some interesting and valuable applications

Like a battery a single ultrcapacitor cell consists of a positive and negative electrode seperated by an electrolyte However ultracapacitor store energy electrostatically like e regualr capacitor not chemically like a battery there is a dielectric seperator dividing the electrolyte also like a capacitor

Th small seperation between electrodes permitted by this structure lead to much higher energy density than a normal capacitor whilst a ultracapacitor stores less enegry than a eauivalenlty sized battery it can release it much quicker as the discharge is not depenedent on a chemical reaction taking place

Because no physical or chemical changes occur when charge is stored ultracapacitorn can also be used many times over without degradation

STEPS TO CONSTRCUT UC MODEL:-

There equation in UC model are defined first which gives us SOC Current and OCS

These are the 3 parameters which infulences UC

* OCV Defines the SOC of Ultracapacitor

* Max Voltage or voltage is directly proportional to the charge stored in the battery

* Amount if the charge is directly proportional to the current that can flow in the ckt

where Q is electric quantity or charge on UC

I is current

Q= C* OCV

Q depends on capacitance which is the charge storage capacity measured in Farads

The Ocv is a measure of the electric field between plates

OCV= integration (I/c)dt

* Capacitance and OCv gives Q

The integration if current over C gives OCV

In UC model calculation for current and SOC are done as said below

Firstly the current consumed is calculated which is fed into a SOC calculation block

* The soc is then calculated based on the amount of current drawn and pushed back into the UC

Hence formula for current is given as

where Q is electric quantity or charge on UC

I is current

Q= C* OCV

Q depends on capacitance which is the charge storage capacity measured in Farads

The Ocv is a measure of the electric field between plates

OCV= integration (I/c)dt

* Capacitance and OCv gives Q

The integration if current over C gives OCV

In UC model calculation for current and SOC are done as said below

Firstly the current consumed is calculated which is fed into a SOC calculation block

* The soc is then calculated based on the amount of current drawn and pushed back into the UC

Hence formula for current is given as

Where

R is the lumped resistance

Vmax is the max voltage

eta is the efficiecncy during the charge discharge cycle

PUC is the power demand which is to supplied by UC and it is there first input in this model which basically comes from enegry management system

As per the equation discussed above the model is constructed and its shown below

Opening it we get see the following blocks

We will see the inside of SOC and current OCV and charge block in the WOrking of Model

Section

Working of Model:

PUC is our input here which is nothing but the power demand for the UC. 20k watts is the value in a complete fuel cell or electric vehicle model it comes from the EMS block, This input gies inside the current calculation block with that inside of current calculation block is shown.

Implementation of current formula stated above

if you see cuurrent and Soc calculation blocks are interconnected then both takes each other in there value calculation The more the current is drawn the lower SOC is going to get Initial SOC has been Set wo 1 which basically means that we are going to draining the ultracapacitor

3. Apart from current the second input to the Soc block is charge Q we know the formula to calculate Q henece we only need to implement that here

With the help of calculated current we can calculate the OCV The formula was stated above and its implementation is shown below.

5. To find the voltage of the UC we need current and SOC as out input which helps us find UC voltages The formula for its shown in simulink representation

5. To find the voltage of the UC we need current and SOC as out input which helps us find UC voltages The formula for its shown in simulink representation

6. As SOC gets calculated we are making simulation end if SOs gets downto 0.2 or 20% The stop and less than block helps us to acheive that

Parameters Value:

C= 100

R= 0.064

eff=0.9

Soc initial=1

V_max= 300

RESULTS:
Current

The current depends upon the various parameter its seems to rise exponentially once its reaches 50A of values 260A is the highest value that capacitor supplied

VOLTAGE:

VOLTAGE:

As we know our max voltage was 300V it seems to be decreasing as more current is demanded from UC at the end of SOC limit that means 20% the voltage value is around 70v

SOC:-