Digital Fusion Power Studio

Priya Sinha

Other Parts Discussed in Thread: UCD3138

Hello,

I have been trying to tune the voltage and current loop in TI- Fusion digital power studio to make it work for my requirement of 2.5kW (400 to 48V ) DC-DC Power converter (PSFB topology) using UCD3138 digital controller in offline mode. I am able to tune Phase margin and crossover frequency by varying various component parameters and Kp,Ki and Kd parameters but not able to tune gain margin. Gain margin is always infinite. Kindly let me know how to tune Gain margin and what parameters in the fusion digital studio affects it.

Also wanted to increase crossover frequency of voltage loop from 1.89kHz to nearly 4kHz . Kindly let me know how to do it.

Thanks and Regards.

over 3 years ago

0 Sean Xu over 3 years ago

TI__Genius 14580 points

Hello,

If you can decrease Kd and increase Ki, you can get higher Fco and more gain margin.

Regards,
Sean

0 Priya Sinha over 3 years ago in reply to Sean Xu

Prodigy 180 points

I changed the capacitor leg value to get the desired Fco. Now I am left with two doubts:

1. In the screenshot attached we need to concentrate on compensating ''stage'' or ''loop'' (in matrices) to achieve a stable system?

2. I have currently focused on compensation ''Stage''. In that I got desired PM and crossover but GM is always infinite, by making changes in Kd, Kp,Ki gain margin is being changed in ''loop'' and not in stage.

0 Priya Sinha over 3 years ago in reply to Priya Sinha

Prodigy 180 points

0 Sean Xu over 3 years ago in reply to Priya Sinha

TI__Genius 14580 points

You need concentrate the loop to get stable system. Power stage is part of the system, please focus on the loop.

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