yea
My thought was just that varying the rpm will vary the frequency, maybe i should say "adjustable" frequency, rather than a constantly changing rpm, but an adjustable rpm would give an adjustable frequency, just like you have a Potentiometer on a pulsing circuit, and maybe you can find a frequency that the alternator works better at, just like chokes have a frequency that gives them a nicer output, the thing is you would have to have a scope hooked up to it to notice any change in wave form. maybe it wont do anything, maybe you can't even get into the rpm range where it would do something.
I keep wondering about this, no conclusion yet, so i'm just asking people about their experience and opinions, trying to learn. I do have a spare Variable Frequency Drive, if I hook it up to the drive motor I can adjust the rpm. It may or may not be worth the effort.
