Paradigm Reference Signature Serie Manuel D'utilisation page 35

POWER FACTOR CORRECTION IN
This Power Factor can be improved by using PFC circuits. These circuits
'smooth out' the pulsating AC current, improving the PF and reducing the
chances of a circuit breaker tripping prematurely.
There are two basic types of PFC: Passive and Active. Passive PFC circuits
are less expensive and typically can correct the PF to about 0.85. Active
PFC circuits are built into the switchmode power supply and can increase
the PF to 0.98 or higher. The closer the PF comes to 1.0, the better the
performance of the power supply. The SUB 2's amplifier employs an active PFC
circuit with a resulting PF of 0.99! Ideally, we want to end up with the input
voltage and current waveforms being sinusoidal and in-phase with each
other, as shown in Fig. 2.
30
SUB 2
(continued)
Fig. 2: Voltage and Current
waveforms are sinusoidal
and in-phase. (PF=1)