FCEV_Challenge_8

Question 1:-

Load the UC parameter file. Complete the Ultracapacitor model. Set simulation stop time to 598 sec.

The model output should give, current, SOC and Voltage as output

Aim)The main aimi is modeling the Ultracapacitor Model with getting outcomes as current ,voltage and SOC.

ANSWER)

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.

The 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.

Fig-->Ultracapacitor

SIMULINK MODEL FOR ULTRACAPACITOR:-

For creating the simulink model for Ultracapacitor model we have to use the following simulink blocks.

1. in1
2. outport
3. product
4. divide
5. subtract
6. suare
7. sqrt
8. constant
9. from
10. goto
11. Integrator
12. Scope

Simulink model :-

There are the 3 parameters which infulences "UC"

1. OCV Defines the SOC of Ultracapacitor
2. Max Voltage or voltage is directly proportional to the charge stored in the battery
3. Amount if the charge is directly proportional to the current that can flow in the circuit.

SOC formula :-

Where:-

>> Eta (η)= Coulomb efficiency.

>>Q =electric quantity or charge on UC.

I=The current.

Charge :-

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

OCV Voltage :-

The OCV is a measure of the electric field between plates.

Capacitance and OCV gives 'Q'

The integration of 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 calcultaion block.

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

Current of UC is given as:-

Where,

1. R is the lumped resistance
2. Vmax is the max. voltage
3. eta is the efficiency during the charge-discharge cycle.
4. PUC is the power demand which is to supplied by UC and it is the first input in this model which basically comes from Energy management systems.

Total Simulink model :-

Step@1)

UC SOC Modeling :-

The SOC is calculated using the following formula.

               SOC = (UC current*UC efficiency)/charge dt

Where, 
efficiency is the Coulomb efficiency of tha ultracapacitor, 
Q is the electric quantity 
I is the current from the ultracapacitor.

SOC Simulink model :-

Step@2) UC Current:-

The current equation is considered as a function of SOC, lumped resistance of the system mainly consisting of the internal resistance of UC and connecting cables.

The current equation is given below.:-

The ultracapacitor current is calculated as

         UC Current= ((SOC*V_max)-sqrt((SOC*V_max)^2-4*R*puc*eff)2*R))

Where, R is the lumped resistance,
Vmax is the maximum voltage of the UC and 
η is the efficiency during the charge/discharge cycle.

Step@3)

Open Circuit Voltage
The Open Circuit Voltage (OCV) calculation is shown below.

The OCV formula is as follows:-

               OCV = int(1/C)dt

Srtep@4) UC Charge:-

The charge_Q subsystem is shown below.

The charge is determined by the product of maximum voltage and capacitance.

The charge formula is as follows:-

              Charge = V_max*C

Step@5) UC Voltage:-

The voltage block subsystem is shown below.

The voltage formula is as follow:-

              
                        Voltage = (SOC*V_max) - (I*R)

By using the ABove subsystem Blocks we can create the "Ultracapacitor " model

OUTCOMES:-

The outcomes of "Ultracapacitor " model are plotted by using the scope block and those are as followes.

>>The Above graph shows the result for ultracapacitor SOC, ultracapacitor voltage and ultracapacitor current.

>>The simulation stop time is 528 seconds.

From the Graph we can see the top plot is for the "UC_Current" with following statistics.

Middle Plot is for "UC_Voltage" with following statistics.

Bottom Plot is for the SOC with following statistics.

Results :-

The required model of Ultracapacitor in simulink is created and Successfully Run with simulation time od 598 sec.

CONCLUSION:- ALL REQUIREMENTS ARE MET

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