First electric calculations

Objectives.

Obtain the first design of an electric system incorporating the photovoltaic cells and the batteries.

  1. Learn what is the current-voltage curve of a solar panel.
  2. Learn the main characteristics of the PWM charger and the MPPT charger.
  3. Learn the variation of the current-voltage curve with the temperature.
  4. Combine these calculations with the André Noth Thesis analysis and check if the actual electric system can support the chosen design.

Procedure.

  1. Check the provided Excel file Calculations with the cells and batteries datasheet. 
  2. Check the temperature analysis following this document: Technical Inforrmation
  3. Write a report justifying the calculation. Pay special attention to the "Check List" section.

We will talk about this task in class.

Let's do it!

First, batteries. For the report:

  1. Check that batteries data from the datasheet is OK in the table. 
  2. Include the figure below (or one of better quality... 😉) and draw a block specifying input and output data with the corresponding Excel cells. 


Second, cells. 

Let's study the photovoltaic cells and answer the next questions:

  1. What is the I-V curve of a photovoltaic cell?
  2. Is there a point (I, V) of maximum power? Why is it interesting?
  3. Does the I-V curve vary with temperature? What parameters in the datasheet specify these variations? Are they specified differently than those used in our reference Technical Information (section 5.2)?
 


Now, for the report:

  1. Check that the photovoltaic cell's data from the datasheet is OK in the table. 
  2. Use information of section 5.2 of our reference Technical Information (section 5.2), to derive the variation of voltage, current and power of the photovoltaic cells. Write it to the report.
  3. Include the figure below (or one of better quality... 😉) and draw a block specifying input and output data with the corresponding Excel cells. 


Third, irradiation. 

Now, it is time to cross this work with your previous UEM Solar analysis task.
  1. Set the irradiation or your month (May, July, June or August) and duration day data.
  2. Check Noth's Thesis equations for calculating available solar energy taking into account the heating of the photovoltaic cells.
  3. Do not forget to set your average power Pave, from the former exercise.
  4. Include the figure below (or one of better quality... 😉) and draw a block specifying input and output data with the corresponding Excel cells. 


And finally, check that the energy available is enough. 
  1. Analyze the green table and check that it is OK.
  2. Include the figure below (or one of better quality... 😉) and draw a block specifying input and output data with the corresponding Excel cells. 

Summarize the calculation and report any discordance/mismatching or potential problem that you can detect in the joint analysis of this task and the previous one.


And that's it. Our second task is done.






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