Are you talking about an inverter? Generators will always make sine waves. Generally speaking, no...there aren't good/cheap filters for a 5.5kw source. The main concern is with motors. Otherwise, you ...

In DDS-mode, only a few commands are needed to e.g. generate a sine wave (orange block), accelerate the frequency (blue block) and lower the amplitude (green block). 23 different AWGs are able to use ...