[Amps] winding an HV transformer (part 2)

[Paul Decker]

BTW, I did try to simulate the result using the 3.4 v p-p signal generator.   I've had some issues believing the result as it seems my signal generator actually produces    -1.7 to +1.7 v pulses.   This makes me think there may be a difference to something truly 0 to + 3.4 V pulses which the diodes may see. 





----- Original Message ----- 
From: "Paul Decker" <kg7hf at comcast.net> 
To: amps at contesting.com 
Sent: Monday, March 30, 2009 5:37:17 PM GMT -05:00 US/Canada Eastern 
Subject: winding an HV transformer 






I've been holding this question for a couple of days now, I'm sure it is very simple and perhaps I just need some reassurance on the answer. 



If you have been following some of this smps discussion, I've got 100Khz pulsed DC (0 - 340v) which is generated by directly rectifing and filtering the 240 V AC mains and providing that into an h-bridge.   The h-bridge dumps the 340 V 100Khz square wave into the transformer. 



As the QST article recomends, I've wound the transformer with five turns on the primary and had calculated that I need 30 turns on the secondary.   Performing some small signal tests, inputting 3.4v pk-pk square wave from my signal generator yeilds about 20.4 volts pk-pk square wave.   I believe this relationship should be linear and inputting 340 V will yeild 2040 volts on the secondary.    



At this point the secondary dumps into a full wave bridge rectifier followed by a filter capacitor.   This is where I am unclear.    When I rectify this with the full wave bridge, will I get 2040 * 0.90 or will I get 2040 * 1.414 as the final DC output?    Part of me says I get the 1.414 value of 2885 VDC, however reading through the handbook, I seem to be reading I'll get 0.90 the output voltage. 



thanks, 

Paul