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Original question:

PSPICE-FOR-TI: How to input coupling parameter

PSPICE-FOR-TI: inductors waveform of SEPIC are not triangle wave when using K_linear

Sky Hsieh48
Prodigy 130 points
Part Number: PSPICE-FOR-TI

Hi,

I simulate a open loop SEPIC use 2 inductors and 1 coupled inductor.

When I use 2 single inductors, waveform of inductors are normal (triangle wave).

 

After I add K_linear in circuit, waveform of inductors become trapezoid.

 

Should I use another model for coupled inductor?

  • 0
    TI__Genius 11215 points

    Hello, 

    Thanks for reaching out. This second waveform looks more like the switch current and the output diode current, can you please double check that the current probes and the labels are placed correctly? What type of coupled inductor is this? Does your simulation result change if another inductor is chosen (with a coupling of ~0.9 for the SEPIC)? We're looking forward to hearing from you soon. 

    Kind regards,
    EM 

  • 0 in reply to EM
    Prodigy 130 points

    Hi,

    Please refer to the location of probes below.

    After I set coupling factor <1, waveforms of inductors became triangle wave.

    I use inductors for SEPIC below. Is that correct to use this inductor and K_linear for SEPIC simulation?

  • +1 in reply to Sky Hsieh48
    TI__Genius 11215 points

    Hello, 

    Thanks for your feedback. For a SEPIC any inductor with low coupling (0.8 to 0.9) is needed, otherwise the waveform might look strange.  Let us know if further support is needed. 

    Kind regards,
    EM