VFD simply could be commercial drivers, literally hundreds of different models.
1st ebay hit as example:
High Quality 3HP 2 2KW 10A 220 250V Variable Frequency Drive Inverter VFD New A7 | eBay
Nearly all of these provide for RS422 or 1515 interface control.
Turbine expansion with PM 6 phase micro generator
To eliminate throttling losses from txv or expansion valve, the liquid to vapor transformation can be done by a turbine that recovers the lost energy of liquid to vapor transformation. Typically used in near absolute zero refrigeration setups.
Turboexpander - Wikipedia, the free encyclopedia
PM= permanent magnet, 6 phase to give smoother dc link for inverter and increase efficiency.