Design of PFC 400Hz

Hello Santhibhushan, 

Thank you for your interest in PFC controllers from TI.

If you already have a 100-W PFC designed for 50Hz input, please see this previous E2E posting: 
https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/842449/ucc38050-ucc38050-pfc-based-smps---operation-on-400hz-ac-input
Although this concerns a different PFC controller, most of my comments apply generally to any 50Hz PFC being used at 400Hz, regardless of controller.

If you are going design a new PFC for 400Hz, then I suggest using the UCC28056C transition mode controller.  
This device has its maximum on time optimized for 50Hz, so the switching frequency may be a bit low for 400Hz.
But Tonmax is not adjustable so there is little flexibility for inductor design.  

An alternative may be the UCC28180 CCM PFC controller which can be programmed for higher switching frequency, but CCM operation is more complex and expensive for this low 100-W power level. 

The PFC design procedures for 400Hz are the same as for 50Hz, except that the voltage loop bandwidth should be adjusted for 0dB crossover at ~80Hz instead of ~10Hz. 

Regards,
Ulrich  

Hello Santhibhushan,

Uli is out so I will cover for him. To reach the 80Hz crossover frequency that Uli mentioned you will need to adjust your COMP values, specifically Rco (R123), Cco (C118) and Cco1 (C120). Please follow the Voltage Loop Compensation section on page 40 of the UCC28056 datasheet (https://www.ti.com/lit/ds/symlink/ucc28056.pdf). 

Repeat the same steps from page 40-42 to find the 3 component values except set Fb as 80Hz. The datasheet example uses a Fb of 6.66Hz.

Regards,

Jonathan Wong

Hi JW,

Thanks for your reply.