[LTSpice] - Find/Make a diode similar to HEM125PA

Discussion in 'General Electronics Chat' started by Henrique Orlandini, Dec 26, 2015.

  1. Henrique Orlandini

    Thread Starter New Member

    Dec 23, 2015
    5
    0
    Hello,

    I've been trying to make a single solar cell model (which should be easy), but I'm having a problem with the diode.

    Basically, a solar cell should be composed with a current source, a diode, one shunt resistor, one series resistor and a load. But the diode isn't a simple silicon one, it needs to have some unique properties (so it'll work as a bypass diode and etc).

    I already tried quite a few diodes from LTSpice library with varied breakthrough voltage and forward current, but none of them seems to give the IV curve from a solar cell.

    I googled some schematic and found a model called "HEM125PA", from Honda. I download the files, put in the circuit and it worked. Basically, the only thing that changed from my circuit to Honda's one is the diode, which I can't get any info about it.

    I opened the .sub file and got this:

    *$
    *PART NUMBER: HEM125PA
    *MANUFACTURER: HONDA
    *REMARK: Pmax=124.7(W)
    *All Rights Reserved Copyright (c) Bee Technologies Inc. 2009
    .SUBCKT HEM125PA Plus Minus
    R_RS1 N00A Plus 500.3637m
    R_Rsh1 Minus N00A 193.200k
    D_D1 N00A Minus DIODE_HEM125PA
    I_I1 Minus N00A DC 0.66001
    .Model DIODE_HEM125PA D
    + IS=52.4058u
    + N=1.1374k
    + RS=300.5273m
    + IKF=0
    .ENDS
    *$


    So, it seems that the .sub contain the whole device description to LTSpice. Anyone with a knowlegde of how to read this can tell me what "IS", "RS", "IKF" means? From what I get, RS1 is the series resistor, Rsh1 is the shunt resistor, D1 is the diode (which I can't get any info about it²) and I1 is the current source.

    tl:dr; I need to find a diode that makes a solar cell work. HEM125PA seems to be one, but I don't have its specifications. Could anyone help me with this? Thanks in advance.

    P.S.: I do not know if "General Electronics" is the right place to post a LTSpice related topic. If it isn't, I'm sorry.

    P.S.2: I tried the Yahoo Group of LTSpice, but they were quite... resistant to give me a diode model, instead they gave me whole circuits which again, I couldn't get the diode info. As a beginner in electronics, the basic are the most important aspect of any project I engage. Thanks.
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    Looks like this panel has a MPP of 125W when loaded with a 367Ω resistor, so that the load voltage is ~215V @ 580mA.

    330.gif

    Try running my .asc
     
  3. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,777
    1,103
    This bit is the diode model:-
    .Model DIODE_HEM125PA D(IS=52.4058u N=1.1374k RS=300.5273m IKF=0)
     
  4. eetech00

    Active Member

    Jun 8, 2013
    648
    110
    Hi

    I created an equivalent circuit from the subckt file (attached)
    I didn't test it.

    The diode is D_D1 and uses the .model DIODE_HEM125PA model definition.
     
  5. Henrique Orlandini

    Thread Starter New Member

    Dec 23, 2015
    5
    0
    I tested both of your suggestions and they worked perfectly.

    And since Alec_t said that IS, N, IKF and RS are part of the diode model, I think I need to know what those mean.

    Thanks.
     
  6. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    Have you read the LTSpice help file for the capital D (diode) component?
     
  7. Henrique Orlandini

    Thread Starter New Member

    Dec 23, 2015
    5
    0
    No, I haven't, but I'll look up for it and read it right now.
     
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