UCD3138FW-PFC: Power management forum

Mownika Gudupuru

Part Number: UCD3138FW-PFC
Other Parts Discussed in Thread: UCD3138

Hi,

1 - I want to change the circuit of UCD3138 Single phase PFC of 360w rating to 2kw rating with 400v output in fusion digital power studio . Could you suggest me the calculations which i need to make for R1,R2,R3,R4,R5,R6 to change circuit from 360 w to 2kw??

2- what is the requited gain margin and phase margin for voltage and current loops to get a stable system ?? How to tune the values of Kp , Ki and Kd ??

Attaching image for your reference.

Thanks & Regards,

Mownika

over 1 year ago

0 Sean Xu over 1 year ago

TI__Genius 11570 points

Hi, Mownika,

I don't think you need change R1,R2,R3,R4 for input voltage sensing. To increase output voltage from 390V to 400V, you can decrease R6 from 1.8k to 1.75k.

To get 2000W power, current is dramatically increased. You need decrease the shunt Rs1 to small resistance, such as 2mohm.

I can't tell what Kp, Ki, Kd are used, you need test them on your hardware. You can refer to application notes:

https://www.ti.com/lit/an/slua709/slua709.pdf?ts=1645635954948&ref_url=https%253A%252F%252Fwww.google.com%252F

There are some application notes in the website. You can get some helps from there.

0 Mownika Gudupuru over 1 year ago in reply to Sean Xu

Intellectual 330 points

Hi,

Thankyou for your swift reply . Can you tell me how to calculate R6 and Rs1 . How did you obtain the above mentioned values ??

0 Sean Xu over 1 year ago in reply to Mownika Gudupuru

TI__Genius 11570 points

R6 (new) = 390V/400V * R6 (old).

Rs1(new) = 360W/2000W * Rs1(old).