Power Factor Controller

[yuchween]

I have a question about power factor control in a rectifier circuit.


I circuit is a rectifier circuit with unity power factor. I am currently doing my thesis on this topic and the rectifier is a boost type at the DC part.

I read about continuous conduction mode for rectifier circuit with fixed frequency and I noticed that it is using a reference iL to determine the shape of the input current waveform.

Now, I a question, what about single cycle control of power factor control is about? We do need reference iL(current through inductor) as well is that right? Single cycle control is another name for variable frequency control as well?


thank you

 

[Hero999]

If the rectifier already has a power factor correction unit built-in, you don't need to add one.

I'm not sure what you're asking.

Are you asking how they design a rectifer with power factor correction?

The problem is a normal bridge rectifier draws the current in pulses which creates harmonics and leads to a poor power factor.

In large three phase units, phase shifting transformers are used to convert the three phase supply into a six or twelve phase supply which makes the rectifiers draw power from more parts of the waveform.

Smaller single phase units use active power factor correction which is just a boost convertor after the bridge rectifier that boosts the voltage to just above the peak value and is designed to ensure a sinusoidal waveform is drawn.