Inverter PWM frequency
Here are a few pictures: -









They are all using (from what I can see) different PWM frequencies to get the same result. Clearly the higher the PWM frequency, the less grainier will be the final sine wave but, on the other hand there could be more losses of you decide to use (say) a 1MHz pwm frequency as opposed to 1 kHz.

The best frequency to use is totally dependent on your input specification and the availability of hardware in your area plus your cost/build requirements. I don't have that information - do you?