Part Number: TPSF12C1
Hi Naresh,
How are you!
I have some questions about the TPSF12C1 that I’d like your help analyzing and solving.
1.According to the quick start calculator note of the TPSF12C1 as shown in Figure 1,Does the TPSF12C1 only address the frequency of the PFC? If comes from the LLC stage and exceeds 200KHz,will it be ignored?
Figure 1:
2.The CSU3200W employs an interleaved AC-switch PFC followed by a full-bridge LLC.the output voltage is 54V, and the switching frequencies are 67KHZ for the PFC and 186KHZ~217KHZ(frequency variation) for the LLC stage.
3.The initial measured conducted spectrum of CSU3200W is shown in Figure 2.it reveals that the common-mode noise energy increases with frequency.
Figure 2:
4.I added a 55mH common-mode inductor at the AC input of the CSU3200W unit, and the resulting conducted spectrum is shown in Figure 3,from the plot there is a clear reduction in amplitude starting at 600KHz,indicating that common-mode noise is dominant.
Fiugre 3:
5. I applied the TPSF12C1 on the CSU3200W model as an active EMI filter, and the measured conducted spectrum is shown in Figure 4. From the plot these frequency points correspond to the LLC fundamental and its odd/even-order harmonics, and the common-mode noise has not been reduced—indicating that the TPSF12C1 is not functioning. Could it be that the TPSF12C1 is unable to handle the common-mode noise generated by the LLC whose energy increases with frequency?
Figure 4:
Thanks a lot!
Best Regard!
Mac.He
