https://cnweiken.aliexpress.com/stor...516455484.html

A DC voltage doubler is actually a pretty simple circuit, it's just that bumping ~340VDC to 530VDC at the currents needed, generally leads to some quite substantial noise/harmonic/interference production.
It's not a problem if done in a suitable enclosure and using suitable filtering, but we all know how the Chinese like their minimalistic approaches to engineering at the cheaper end of the market...

But having said that, I am considering one of these boost VFDs for my big mill (it's maybe a physical big mill, but its old enough to only have a 3KW motor). The 4KW is only $205 delivered, so it's not the end of the world if it turns out to be hopeless and wipe out all electronics in the neighbourhood :-)