PFC is a circuit which corrects the current and voltage phase shifts to increase efficiency and it provides 360v or 400v at its output which eliminates the line regulation for the SMPS circuit and also some PFC cancels out input harmonics/noise to improve power factor.

We took television power supply which have PFC ic OB6563 we disconnected the further section tested it works fine without any load it shows 0.99 PF on our power meter but if we try to connect any ready made SMPS or adapter circuits PF factor drops. i know PFC are design for different wattages so this is not a right way to find but my question is if we built a PFC which is giving 1 PF should the further connected ckt should make any diffrence in power factor correction i mean bad smps design or bad flyback transformer design can affact to the PFC? If yes than how ? im asking this because we currenty have smps which is laboratory made which is of copper clad board etched and transformer is also hand winded with manual calculations without having correct bobbin and core specs data.

Mainly we dont have current probe so i can see the current voltage graph on DSO.

 

PFC is a circuit which corrects the current and voltage phase shifts to increase efficiency and it provides 360v or 400v at its output which eliminates the line regulation for the SMPS circuit and also some PFC cancels out input harmonics/noise to improve power factor.

We took television power supply which have PFC ic OB6563 we disconnected the further section tested it works fine without any load it shows 0.99 PF on our power meter but if we try to connect any ready made SMPS or adapter circuits PF factor drops. i know PFC are design for different wattages so this is not a right way to find but my question is if we built a PFC which is giving 1 PF should the further connected ckt should make any diffrence in power factor correction i mean bad smps design or bad flyback transformer design can affact to the PFC? If yes than how ? im asking this because we currenty have smps which is laboratory made which is of copper clad board etched and transformer is also hand winded with manual calculations without having correct bobbin and core specs data.

Mainly we dont have current probe so i can see the current voltage graph on DSO.

In order to measure the PF , it is necessary to connect the load. Your measured PF value doesn't make sense . Load with a powerful resistor or incandescent lamp to understand if your controller is working at all

 

Certainly the power factor to be adjusted is what exists in actual operating conditions. So measure it under THOSE conditions, it may be quite different.

 

In order to measure the PF , it is necessary to connect the load. Your measured PF value doesn't make sense . Load with a powerful resistor or incandescent lamp to understand if your controller is working at all

yes i have just mentioned that just because to tell that my PFC circuit is working fine.

 

Certainly the power factor to be adjusted is what exists in actual operating conditions. So measure it under THOSE conditions, it may be quite different.

hello,
Thanks for reply. We have PFC stage and SMPS tried different load levels from min to max current capability still it give max 0.66 PF how to know wheather its due to PFC circuit or due to smps circuitry specially the flyback transformer which is DIY.

In this case we are using UCC28180 as PFC and UC3845 as switching ic for SMPS and without pfc section we get only 0.29PF. we dont have current probe to see the wave form on DSO for the capacitive load current is leading while voltage is lagging and for inductive load vice versa.

 

You can monitor the current on the Rsence resistor using an oscilloscope powered by a built-in battery.
Or power the oscilloscope from a transformer for galvanic isolation from mains voltage. This is all so as not to damage the input of the oscilloscope.

 

yes i have just mentioned that just because to tell that my PFC circuit is working fine.

1. Disconnect the flyback inverter.
2. Connect a high-power resistor in place of the flyback
3. Read PF value on the power meter

Resistor value can be found like this-

R = U^2 / P

where U is PF corrector output voltage (360 or 400V as you said before )
P is output power in watts

Now you will see how PFCs work with active load, not with flyback .
This will determine if the corrector is working fine