Introduction to Digital Power Conversion
XMC4000/1000 Family
Modulation
Application Guide
76
V1.0, 2015-01
6.9
CCM: PFC example using Average Current Mode Control
For high power PFC rectifiers, Average Current Control (ACC) is preferable. These do not suffer the
same degree of noise sensitivity as a PCC and do not cause as much EMI. The ACC PFC rectifiers
show better EMC conditions for high power converters.
There is a higher loop gain in ACC, compared to the loop gain in PCC. This is due to the integration of
the error signal in the feed-back loop algorithm that aligns the average current envelope to the
sinusoidal half-wave curve |V
AC(t)
| of the input voltage.
The ACC control algorithm needs sensing of the input voltage sinusoidal half-waves |V
AC(t)
|, by a feed-
forward loop (The feedback of the output voltage is implicit, but not shown in the following figure).
Figure 61
Mode CCM
– PFC Using Average Current Mode Control – Example
