Please help to convert: 115V 60Hz to 400Hz

I am new to this fourm. I am an undergraduate at SJSU. I need help on how to change the frequency of the line to 400Hz?
basically, I am trying to run a fan that requires 115V 1A 400Hz. I can do the regulating of the line, vary from 90V to 255Vac. Isolating the line is just a transformer, I believed. Please advice on how to change the frequency. Thank you.

You might be able to get a motor-generator(actually alternator) from a surplus place like Nebraska Surplus sales. Lots of WWII surplus from planes and ships used 400 Hz so the problem is not a new one. I realize that this might not be the answer but you might find the information you need from people who collect and operate WWII surplus military equipment - there's a few guys out there still doing it.

the way i think of it is to rectify the mains, filter it and then use a sinusoidal oscilator to generate the 400Hz