# Why is my steady state analysis of a dc-dc converter aborted due to errors?

**URL:** <https://forum.plexim.com/t/why-is-my-steady-state-analysis-of-a-dc-dc-converter-aborted-due-to-errors/279>\
**Category:** PLECS\
**Tags:** frequency-response, ac-sweep, steady-state-analysis\
**Created:** [February 16, 2018, 9:34am UTC](https://forum.plexim.com/t/why-is-my-steady-state-analysis-of-a-dc-dc-converter-aborted-due-to-errors/279 "2018-02-16T09:34:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![EMdude](https://avatars.discourse-cdn.com/v4/letter/e/71c47a/32.png) [@EMdude](https://forum.plexim.com/u/EMdude)\
**Post date:** [February 16, 2018, 9:34am UTC](https://forum.plexim.com/t/why-is-my-steady-state-analysis-of-a-dc-dc-converter-aborted-due-to-errors/279/1 "2018-02-16T09:34:06Z")

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Dear Community,

As I am trying to get the frequency response of DC/DC converter,exactly the control to error transfer function Vout(s)/Verr(s) (Verror=Vref-Vout). after launching the analysis I get this error message as shown in the image attached.

best regards,

 ![dcdcplecs_error.PNG](https://europe1.discourse-cdn.com/flex006/uploads/plecs/original/1X/0c981bff6c95490734336b9c99ed3977a532a907.png)

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**Author:** ![Falk\_Kyburz](https://avatars.discourse-cdn.com/v4/letter/f/67e7ee/32.png) [@Falk\_Kyburz](https://forum.plexim.com/u/Falk_Kyburz)\
**Post date:** [February 16, 2018, 10:16am UTC](https://forum.plexim.com/t/why-is-my-steady-state-analysis-of-a-dc-dc-converter-aborted-due-to-errors/279/2 "2018-02-16T10:16:55Z")

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It didn’t find a steady state. This means your system takes too long to get to the steady state from simulation start.

A simple fix would be to switch to “Stored system state” in the Initialization tab of the simulation preferences. You must store a state where the system is in steady state. For example after a normal simulation.

Another possibility is to set the number of init cycles in the Analysis Tools dialog.

I strongly advise using the “Help” button in the Analysis Tools to get to the documentation. There you find:

[…]Number of init. cyclesThe number of cycle-by-cycle simulations to be performed before the Newton iterations are started. When an analysis fails to converge because the starting point was too far from the steady-state solution, this parameter can help to get better starting conditions. The default is 0. […]

Cheers

Falk

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**Author:** ![EMdude](https://avatars.discourse-cdn.com/v4/letter/e/71c47a/32.png) [@EMdude](https://forum.plexim.com/u/EMdude)\
**Post date:** [February 16, 2018, 11:06am UTC](https://forum.plexim.com/t/why-is-my-steady-state-analysis-of-a-dc-dc-converter-aborted-due-to-errors/279/3 "2018-02-16T11:06:03Z")

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Thanks Falk for the hint. I have solved this problem by giving a number 25 for the number of iterations but I am bit confused whether it will impact my result or has no impact.

I have also got another issue after this my body shows only half of the frequencies, not the whole frequencies as you can see in the image.

just a detail, I have placed my perturbation between the PI controller and the subtraction block

 ![dcdc_error.PNG](https://europe1.discourse-cdn.com/flex006/uploads/plecs/original/1X/2bf1dc1a36af816e2f5a26a1139d96ed77cad8de.png)