On Thu, Feb 12, 1998 at 10:14:55PM +1030, Brett Lymn wrote:
> >Its not clear to me yet that sine wave output wins.  Square wave
> >should be more efficient since you don't have the big dead-time
> >between, the two peaks.
> 
> Urrgh no.  Firstly, there is no dead time - the voltage continuously
> changes.

Well, the current SMPS machines have capacitors which charge to the peak
value of the input voltage.  With sine wave input, the input current is
zero until the voltage approaches the peak voltage, then drops back to
zero for the rest of the half-cycle.  So, a square wave would be better
(the peak current would be lower, for example).

But yes, square wave generates more noise than sine wave and causes
problems with transformers, motors etc.

  -jm