Terminology of AC -DC converters
The schematic shows a basic 3 phase inverter with back-EMF clamp diodes which may also be used with a generator to convert AC to DC and appropriate changes in phase-control of gates. With that additional application in mind, it can support bi-direction conversion.  

The DC to AC conversion feature alone is most commonly referred to as an AC Inverter.

The article entitled HIL co-simulation of finite set-model predictive control using FPGA for a three-phase VSI system  is a post-graduate level article that does not focus on these basic controls. These are perhaps better described in your beginner electronics textbook or in Wiki.