p spice simulation problem

Discussion in 'Electronics Resources' started by easty, Dec 11, 2013.

  1. easty

    Thread Starter New Member

    Dec 11, 2013
    4
    0
    Hi peeps
    I am new to pspice and trying to get my head round some of the functions. I am at present trying to model a pv cell and have have managed to simulate the outputs for different levels of irradiance. I am now trying to determine the max power point and the power locus. This is just basically a product of Y x X. The problem is that I have absolutely no idea how to do it. Any chance anyone could point me in the right direction. I realise this is probably just a simple command, but if you do not know then you do not know.
    Cheers
    Dave
     
  2. t06afre

    AAC Fanatic!

    May 11, 2009
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    Do you want to plot the power in some component (like say a resistor) or just the product of two values. What kind of simulator software are you are using?
    Anyway this may help you. But for effect in a component. You can plot this directly from spice
    Code ( (Unknown Language)):
    1. * Mult function
    2. * Each input is added to its respective offset and then multiplied by its gain.
    3. * The results are multiplied along with the output gain and added to the output offset.
    4. * Z = ( (X + x_offset) * x_gain * (Y + y_offset) * y_gain )* out_gain + out_offset
    5. *
    6. *
    7. *Connections:
    8. *            X
    9. *            |  Y
    10. *            |  |  OUT
    11. *            |  |  |
    12. .SUBCKT MULT 1  2  3 PARAMS: x_offset=0.0 y_offset=0.0 x_gain=1.0 y_gain=1.0 out_gain=1.0 out_offset=0.0
    13. A1 [1 2] 3 sigmult
    14. .model sigmult mult(in_offset=[{x_offset} {y_offset}] in_gain=[{x_gain} {y_gain}]
    15. +                   out_gain={out_gain} out_offset={out_offset})
    16. .ENDS MULT
     
  3. easty

    Thread Starter New Member

    Dec 11, 2013
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    0
    I wish the plot the product of 2 values. it just the current against the voltage.
    I have modeled a pv cell using a netlist, for different value of irradiance. I need to now find the power curve for each level irradiance now, but do not know how to do it,

    I am using the DESIGN ENTRY CIS in PSpice. It uses the Pspice A/D simulation.

    Below is the code I have used.

    Code ( (Unknown Language)):
    1. .include cell_1.lib
    2. xcell1 0 31 32 cell_1 params:area=650  j0=5.84e-8 jsc=2.76e-3
    3. vbias 31 0 dc 0
    4. .param IR=1
    5. virrad 32 0 dc {IR}
    6. .step param IR list 200 400 600 800 1000
    7. .plot dc i(vbias)
    8. .probe
    9. .dc vbias -0.1 0.6 0.01
    10. .end
    Code ( (Unknown Language)):
    1. *MODEL LEVEL 1
    2. *SINGLE DIODE AND CURRENT SOURCE
    3. *BUILT-IN SPICE DIODE MODEL D
    4. *NODES
    5. *   (300)REFERENCE
    6. *   (301)OUTPUT
    7. *   (302)INPUT, IRRADIANCE
    8.  
    9.  
    10.  
    11. .subckt cell_1 300 301 302 params:area=1, j0=1, jsc=1
    12. girrad 300 301 value={(jsc/1000)*v(302)*area}
    13.  
    14. d1 301 300 diode
    15. .model diode d(is={j0*area})
    16. .ends cell_1
    17.  
     
  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    LTSpice knows how to do this intrinsically. You can run any simulation, which by default saves the voltage at each node (as a function of the independent variable of the simulation, i.e. time), and the current through each component. To show power in any component, it is as simple as holding down the Alt key while pointing to the component with the cursor. Power is plotted in Watts.

    You can also do it using "waveform exressions". You can plot the expression V(node) * I (component) for example, which is power in Watts.
     
  5. easty

    Thread Starter New Member

    Dec 11, 2013
    4
    0
    Thank you, I will give it a go this afternoon. I realised it would be a simple function but as I am trying to run before I can walk with a new piece of software, sometimes the simple functions are difficult.
     
  6. easty

    Thread Starter New Member

    Dec 11, 2013
    4
    0
    I have uploaded the graph that I want to find the power curves for. Can anyone tell me how I can multiply the x and y axis' together?

    Cheers

    Dave

    ps I am using net lists to generate outputs. I am not using and component design at all.
     
  7. t06afre

    AAC Fanatic!

    May 11, 2009
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    Perhaps you have some export options in your charting windows. If you post your schematic (handdrawn?) and tell which spice software you use it will be more easy to help. As said before you can plot the power in any component directly from spice or a mathematical expression of two or more nodes.
     
  8. MikeML

    AAC Fanatic!

    Oct 2, 2009
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