SpeedFit Design Simulator limits max. inductacne value I can enter

im_zg

Hi, I am trying to simulate the circuit using SpeedFit Design Simulator, but when trying to enter a filter inductance value, I get a warning message: Inductance must be smaller than xy mH in order for the circuit to operate within user specifications.

The LC filter parameters calculated and verified using other numerical tools give me 28 mH and 3 uF. SpeedFit 2.0 Design Simulator limits the value to 15.999 mH.

Can you please clarify:

i) how SpeedFit 2.0 Design Simulator calculates max. inductance (15.999 mH) and

ii) will there be any issues if I use 28 mH instead in the real model; and simulate with e.g., 15 mH?

I have attached the simulation report for the reference. I can also provide equations I used to get 28 mH and 3 uF for the output LC filter.

Kind regards.

Document.pdf

TBhatia

Hello, thank you for your message. A member of our technical team is looking into your questions and we will respond shortly. 

im_zg

Hi TBhatia,

did you maybe get an update on the maximum inductance value that can be used in the model? It this limited by the SpeedFit model, the MOSFET or any other parameter (e.g., switching frequency, voltage, etc.)?

Kind regards

ZMiller

Hi,

For the 3 Phase Inverter application, the filtering component is limited to a series inductor (no capacitance). The maximum value is selected to ensure proper operation of the controller used in the PLECS simulation file and it is a function of the input parameters (line frequency, switching frequency, Vin, Vout, etc.)

Using Speedfit, you should be able to easily compare different switching devices using the default inductance values. For your final design, I would recommend modeling your inverter with the LC filter you have described and observing its behavior.

Thanks,

Zack

ZMiller

Hi,

Thank you for your question. I will go ahead and close this discussion.

Thanks,

Zack