What does "power PFC" mean?
Active PFCThe active PFC is composed of inductors, capacitors and electronic components. The size is small, and the waveform of the current is adjusted by special IC to compensate the phase difference between the current and the voltage. Active PFC can achieve higher power factor - usually more than 98%, but the cost is relatively high. In addition, active PFC can also be used as an auxiliary power supply, so in the active PFC circuit, there is no need for standby transformer,
Valley fill circuit is a new type of passive power factor correction circuit, which is characterized by the valley fill circuit rectifier behind increasing rectifier conduction angle by filled valley points, the input current from the peak pulse becomes close to sinusoidal waveform, the power factor is increased to 0.9 so, obviously reduce the total harmonic distortion. Compared with the traditional inductance passive power factor correction circuit, it has the advantages of simple circuit, remarkable power factor compensation effect, and no large volume and large weight inductor is needed in the input circuit.
Passive PFCPassive PFC is generally divided into "inductance compensation" and "valley fill circuit (Valley Fill Circuit)" and "inductance compensation method" is the fundamental AC input current and voltage phase difference between the reduced to improve the power factor, including passive PFC mute type passive PFC and non mute type passive PFC. The power factor of passive PFC can only reach 0.7 ~ 0.8, which is usually near the high voltage filter capacitor.
brief introductionThe computer switching power supply is a capacitive input circuit. The phase difference between the current and the voltage will cause the loss of the switching power. At this time, the PFC circuit is needed to improve the power factor. There are two kinds of PFC at present, one is passive PFC (also called passive PFC) and active PFC (also called active PFC).
PFC English called "Power Factor Correction", meaning "power factor correction", power factor refers to the effective power and the total power consumption (apparent power) the relationship between the effective power is divided by the total power consumption (apparent power ratio). Basically, the power factor can measure the extent to which the power is effectively utilized. When the power factor value is greater, the higher the power utilization rate is.
