FUSION-DIGITAL-POWER-STUDIO: UCD3138

Hello this request has been passed to the systems engineer.

Hello, 

You need change the hardware, scale down current feedback signal, then you can update some parameters accordingly on FDPS.

At different max power level, voltage loop and current loop need be tuned, and it had better you look at the waveform to tune the loop. 

Regards,
Sean

How to tune the voltage and current loop?? Can you elaborate on this??

Hi Sean,

I have undergone through above document but i couldn't get idea how to tune. .Moreover I do not have the Venable machine..

Hope you would help me..

Hi Sean,

I have undergone through above document but i couldn't get idea how to tune. .Moreover I do not have the Venable machine..

Hope you would help me..

Hi Sean,

I have undergone through above document but i couldn't get idea how to tune. .Moreover I do not have the Venable machine..

Hope you would help me..

Hi Sean,

With respect to EVMPFC-026 is there any specific parameters that we need to obtain from plots in FDPS??

According to my study we need to obtain a stable loop which means Phase margin and gain margin should be greater than zero . Is this sufficient??

Also how to get lower voltage loop and higher current loop bandwidth?? What are the parameters that I need to change??

Normally, phase margin need be at lease 45 degree. CC loop band width need be 5K above, and Voltage loop need be 10Hz roughly. You can find more details from SLUA709, I emailed the link to you.

What about the gain margin??  How to calculate Kp, Ki, Kd, Alpha to get a stable system . I have referred SLUA709 but could not get the ides. There is no proper calculations available.

From ROT, 10dB is good for gain margin.

There is a calculation document, and you can google  it.

UCD3138 Control Theory - TI E2E

Thank you Sean,

I have referred the above document. But my doubt is how to convert the whole circuit of single phase evm to traditional analog controller??

If I could bring the whole circuit to analog form then i can calculate all the constants.

Attaching analog controller from UCD3138 control theory.

Single phase evm:

You may look for some analog PFC controllers (UCC28180, UCC3818) and their application notes. You can get  a lot of loop design knowledge. 

Hi Sean,

There are two loops for EVMPFC026. One is current loop and the other one is voltage loop. Is Phase Margin of 45 degrees and Gain Margin of 10db ideal for both current and voltage loop ???

Hi Sean,

I am not an expert and started learning. I have referred analog PFC controllers but I could not understand how to do loop design of digital controllers .I could not find a perfect document to make the loop design .Need help in this loop designing so that I could continue my work further.

Thanks &Regards.

Hi, Mownika,

By ROT, it is right. It can help the loop stability under component tolerance.

Regards,
Sean

Please try to google the document. It provides a lot of details.

UCD3138 Control Theory - TI E2E