Week 8 Challenge

A TypicalUltracapacitor

A capacitor has a constant of proportionality called capacitance symbol C which represents the capacitor’s ability or capacity to store an electrical charge with the amount of charge depending on a capacitor capacitance value as Q ∞ C

Following Steps are used to construct the ultracapacitor model

Here we have an equation in UC model are defined first which gives us SOC Current and OCS

These are the 3 parameters which used in UC

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

here,

• dta is the Coulomb efficiency.
• Q is the electric quantity or charge on UC.
• I is the current.
• 
• • Here mainly Q depends on capacitance which is the charge storage capacity measured in measured in Farads.

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

• 

  • Here the 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:
  • Here Firstly the current consumed is calculated which is fed into a SoC calcultaion block.
  • So The SoC is then calculated based on the amount of current drawn and pushed back into the UC.

  Hence fomula for current is given as:

• 

  here,

  • R is the lumped resistance
  • Vmax is the max voltage
  • dta is the efficiency during the charge discharge cycle.
  • PUC is the power demand which is to supplied by UC and it is the first input in this model which basically which comes from Energy management systems.
  • So based on the above equations now we designed a simulink model

Simulink model :

Subsystem of the Ultra capacitor:

• Here We can see the SoC and Current and voltage OCV and charge block in working model section

Current and voltage subsystem :

• Here PUC is our input here which is nothing but the Power demand for the UC 20K watts is the input value.
• In a complete Fuel cell or electric vehicle model it comes from the EMS Energy management system block.
• So This input goes inside the Current calculation block With that inside of Current calculation is done

To Implement the Current formula above discussed:

Here we need SoC in current calculation

So the SoC block used for implementation which as shown below

• Here we can see current and SoC ccalculation blocks are interconnected then both take each others quantity in there value calculation.
• So if The more the current is drawn the lower the SoC is going to get.
• The Initial SoC has been set to 1 which is basically that we are going to draining the Ultracapacitor.

Here Apart from current the second input to the SoC block in charge Q.

We aslo need to know the formula to calculate Q we should implement in the next step

• By the help of calculated current we can calculate the OCV.
• Here The formula was stated above and its implementaton is shown below

• Here To find the voltage of the UC we need current and SoC as our input which helps us to find UC voltage.
• So The formula for it is shown in below

Calculation of SOC block:

• The input paramters we loaded are:
• C= 100
• R= 0.064
• eff=0.9
• Soc initial=1
• V_max= 300

Output results:

1) Uc_current :

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

2) Uc_ Voltage :

• Here we know that 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

3) SOC_Uc :

Conculsion :

We Loaded the UC parameter file. and Completed the Ultracapacitor model. and we Seted the simulation stop time to 598 sec.

The model output ontained is current SOC and Voltage as output