Three Phase Power supply
Dear members,
I am in need to design and develop a wide range power supply for Three Phase Industrial application.
I have gone through an article published in Power Systems Design Europe November 2006 for a wide range Three Phase power for Industrial Applications and designed an enhanced Three phase power supply with higher power rating.
I have attached the design file herewith. Can someone please suggest whether the design is correct.
Thanks
with regard,
K.S.Rajan
Comments
Dear Mallora,
Greetings...
Thanks for the support. I will incorporate your suggestions.
Thanks
with warm regards,
K.S.Rajan
per the comment above, you need to link across the middle of C17, C2 to R10, R11 and along to C4, C18 and along to R53, R57 to balance the volts on the caps. C3 could be removed or made into a split cap like the others are. 400/230Vac gives 565V nominal but easily +20% = 680Vdc - and far higher with transients encountered in the field.
Repeat L1//R52 in the positive line and put both of them straight after the diodes.
Use 1200V input diodes or put 2 x 4007 in series in every spot, to give a longer life to your bridge, 1kV spikes are common.
Put chokes like L1 in series with R40, R 7 -9 for transient immunity ( & EMC filtering).
Ideally you need 1A fuses 630Vac rated with suitable rupture capacity on the 3 phases ( NOT the neutral)
C27 needs to be Y1 rated - important...!
L2 and L5 are far too large, say 100uH and 22uH on the 5V
C21, C24 are far to small.
You could double up the opto feed back for extra reliability.
You need a resistor across the opto-led (1k) and a resistor in series with the zener to limit the current to non destructive levels.
the main output diode SB550 if carrying 3A ave (12A pk) with have a Trise of 60C at least, and risks thermal runaway, use 2 in parallel //. put 4u7 MCLL close to the diodes and o/p winding to limit overshoot on the windings at fet turn off.
Also, just noticed - R63 is a bad idea where it is positioned...
Lastly - the phasing or dot notation as shown on the transformer is wrong.
Hi rajanks,
At the primary side, if you are operating with 3phase 380Vac-440Vac, C3 450V rating is not enough. You can use those 800V rated ceramic caps with lower capacitance since this should only be a bypass cap to minimize loop from TR2 to U10 S-pin. For the bulk caps in series, you should connect center of C2 and C17 to center of R10 and R11, same thing with C4, C18, R53 and R57. This will make sure that the capacitors in series are charging at the same rate to prevent exceeding capacitor rating with uneven charging rate. Then Source PIN of U10 should be connected to Bulk- C3/C18.
On secondary side, for better regulation tolerance you might want to check adding TL431 instead of zener and some compensation for better transient response. See schematic on page-8 of below link. Hopefully it helps. Thank you.
https://ac-dc.power.com/sites/default/files/product-docs/tinyswitch-4_family_datasheet.pdf