From: email@example.com (Bob Wilson)
Subject: Re: How to making AC to DC converter ?
Date: Wed, 16 Oct 2002 02:59:40 -0000
Organization: Your Organization
X-Newsreader: WinVN 0.99.9 (Released Version) (x86 32bit)
In article ,
>I want to make "AC to DC converter", if possible without transformer
>in order to avoid harmonics in transformer. I want this converter have
>specification as follows :
>+) Input AC with :
> -) Voltage range : 90 - 300 volts
> -) Frequency range : 40 - 70 Hz
>+) Output DC with voltage 12 volts
>+) Output power 450 watts or 700 VA
>+) I want the output of this converter also have filter (maybe an
>active filter) to eliminate noise and ripple from the voltage
> Because that, i ask yours help. If you have circuit diagram and PCB
>layout for this converter, please send to me (Irsyadoel@yahoo.com)and
>also include the list of components that use in the circuit.
> For your attention and help, i say thanks.
Without a transformer?? The only possible way is using a buck or similar
non-isolated switchode topology, but this would be totally senseless for the
large ratio of input to output voltage ratio you want (the duty cycle would
be razor-narrow and very hard to control). But if you think a normal AC
transformer has "harmonics", just wait 'til you look at the output of a
switchmode power supply!
By the way, what is it that you want, anyway? 400 "Watts" or 700 VA? Output
is rated in VA in any case (not Watts, since there is no power *consumed* at
the output), so this is more than a little confusing. You cannot have both
400W and 700VA at the same time!
You are also way off base with the suggestion of using an active filter at
400 Watts. Active filtes are used in low signal applications, not in high
power circuits (how are you going to run 400 Watts through a series of