How should the value of the variable inductance be set?

PLECS
1

Dear PLECS Forum Members,

I am currently working on a simulation in PLECS and have encountered an issue when replacing a fixed inductor with a variable inductor.

In my original circuit, the inductance is set to 2 mH, and the system operates stably. However, when I replace the fixed inductor with a variable inductor while keeping the intended inductance value at 2 mH, the previously stable system begins to oscillate.

I would like to ask the following questions:

  1. How should the variable inductor be configured to achieve a constant inductance of 2 mH?

  2. Why does replacing a fixed inductor with a variable inductor cause oscillations, even when the inductance value is intended to remain unchanged?

  3. Are there any differences in the modeling or numerical implementation of these two components that could explain this behavior?

The main circuit and the PCC current waveforms after replacing the fixed inductor with a variable inductor are shown in the figures below.

09ef0077e7483fd80a9565d875a7973a
09ef0077e7483fd80a9565d875a7973a1535×500 35.5 KB

2fd522f41f51ca26a8307ea9ba45ef7e
2fd522f41f51ca26a8307ea9ba45ef7e719×349 5.25 KB

I would greatly appreciate any guidance or suggestions on how to configure the variable inductor correctly.

Thank you very much for your time and help!

Best regards

2

I suspect that you may have swapped the two inputs of the Variable Inductor.

To reproduce a fixed inductance of 2 mH, the inputs should be:

  • L = 0.002 H

  • dL/dt = 0 H/s

Please check that these values are connected to the correct input ports. If the problem persists, please share your PLECS model so that we can investigate further.

3

Thank you very much for your detailed explanation. My problem has now been resolved. I appreciate you taking the time to assist me.

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