For whats its worth I bought this Fuling 3.7kW VFD, supposed to have vector control but I believe its only up to a certain amount of Hz. I'm in Australia running it on single phase 230-240v power.
It's run perfect so far with my jianken JGH105/2.2kw, 800Hz, 4 pole spindle. Something tells me the extra torque from being '4 pole' isnt really there OR I have the VFD set up funny. It seems to bog doe easier than some 2 pole spindles I have seen when taking the same cuts etc. Even still it's done the job very well for a while now, I just set it to 550-600Hz and that does 99% of my cutting.
https://www.aliexpress.com/item/1005...21ef1802exZHWp