AC Mains Inverter Refresher: exotic advantages?

[tim9000]

Hi,
Could I please get some conformation and clarification:

So the more phases an inverter has, the less ripple will be on the DC bus, and the higher the switching frequency the inverter is operating at, the closer the approximation is to a sine wave. These are the advantages?
But what are the harmonic advantages? Do they come from a higher switching frequency or more phases? or both?
I'm betting the switching freq. (?) But I've heard that having more phases in an inverter means there is less harmonics seen by the source, why?

Also, when considering a motor fed by more phases then 3, would there be any benefit to using more phases? (like a better MMF approximation) or what would the implications be? (such as to the life of the motor)

Thanks

 

[Averagesupernova]

I guess I would like a bit of clarification on the type of invertor you are referring to. Are you talking about variable frequency drives used with 3 phase motors and whether or not they are run from a single phase or 3 phase source? It is true that when rectifying an AC source more phases means a higher ripple frequency which is easier to filter and as a result reduce the level of ripple. I can't see how this would translate to a higher or lower switching frequency. In summary it is safe to say that less ripple is always better and higher frequencies in power electronics requires smaller magnetic components and is often a savings. But with most things in engineering, the perfect design is often simply the best compromise(s).