Electrolytic capacitor for mains PSU

[rayma]

What's better spec first the ripple or the esr?

Ripple for the input cap, and esr for the other caps.

 

[merlin el mago]

Good caps are a little bit expensive:

ALS40A221DE450 | Condensador electrolitico de aluminio KEMET ALS40A221DE450, 220μF, +-20%, 450V dc, Montaje en Panel, 487mΩ | KEMET

PEH200YC3220MU2 | Condensador electrolitico de aluminio KEMET PEH200YC3220MU2, 220μF, +-20%, 450V dc, Montaje en Panel, 240mΩ | KEMET

 

[merlin el mago]

PSU question

I don't know what to do to improve better the PSU, input choke or a high ripple low impedance capacitor?

PEH200YC3220MU2 | Condensador electrolitico de aluminio KEMET PEH200YC3220MU2, 220μF, +-20%, 450V dc, Montaje en Panel, 240mΩ | KEMET

ALS40A221DE450 | Condensador electrolitico de aluminio KEMET ALS40A221DE450, 220μF, +-20%, 450V dc, Montaje en Panel, 487mΩ | KEMET

The hammond choke cost 20-21€00 and the capacitor 20-32€00.

Wich one will be more effective and with the best SQ?

 

[JonSnell Electronic]

It depends on many characteristics.
Power required, voltage sag, type of rectifier and whether bridge, doubler or half wave. Dual rail, single rail etc etc etc.
A bit of background may help you get an answer that is not just a guess.

 

[DF96]

What is wrong with the PSU? You have to decide what aspect of performance you want to improve, then choose an appropriate method for doing it. Numbers may help.

Which PSU? Are we supposed to guess?

 

[merlin el mago]

I'm designing two PSU only for B+, requirements are:

One PSU 170VDC drawing 142mA

Other PSU 60VDC drawing 7mA

I'm thinking LCRC or CRCRC both possibilites, Power tx on hand 150VDC 30VA 200mA & 230VDC 120VA 500mA. If necessary I will order new one.

Rectifiers bridge 4 Sic Cree C3D02060F 4A 600V on each PSU

 

[6A3sUMMER]

Generalizations:

Choke input has output voltage of 0.9 times the primary winding rms.
Cap input has output voltage of 1.414 times the primary winding rms.
(winding = whole for bridge rectifier, winding = 1/2 for center tapped full wave rectifier).

Chokes are expensive, take real estate, and spray magnetic fields.
Choke input has stable output voltage versus load.
Choke input makes the power transformer run cooler.

Capacitors are less expensive, take less real estate, but they do cause (voltage) ground loops and spray magnetic fields according to the aperture of the loop.
Cap input has less stable output voltage versus load.
Cap input makes the power transformer run hotter.

All generalizations have exceptions.

 

[DF96]

The transformers you have seem a poor match to your DC requirements. However, you could use the 230V one into a choke input PSU to get somewhere around 200V which you then drop to 170V. 60V then from a regulator.

 

[merlin el mago]

Yes, you are right, I'm using the 230V one for 170V with CRCRC. I'm trying to avoid sand regulators or maximum using VR tubes, do you know VR tubes to get 170V and 60V?

I get only VR for 75, 90, 105, 150V.

 

[DF96]

VR are only available for certain voltages.

 

[merlin el mago]

Yes I know, I will design the PSU choke input LCRC and buy power transformers accordingly.

 

[merlin el mago]

Attached PSUDII simulation, finally the best result will be LCRCRC.

 

[DF96]

Rmember that once you have filtered the ripple below a certain level, further improvement comes from getting the grounding right not adding more filtering.

 

[merlin el mago]

Thank you for the advice.