Variable Frequency Drive Circuit
That schematic is correct, but a huge simplification only intended for understanding the core function of a voltage source topology variable frequency drive.

It lacks a lot of stuff: gate drivers for the IGBTs, snubbers for the IGBTs, power supplies for the gate drivers, control logic (in the form of an ASIC, a digital signal processor and/or a FPGA), power supply for the control logic, galvanic isolation of the external control inputs, user interface, current sensing circuitry, voltage sensing circuitry, possible cooling system (fan), input filtering, output filtering and more.  

Then there is the software to control it all, which isn't trivial to do properly. A crude implementation might only take a week or so for an experienced embedded programmer to do, but a proper control system like direct torque control would take much more development effort.  

It's certainly possible to make a homemade VFD (especially if you sacrifice reliability, safety and feature set), but it's not going to be economical in either money or time. I'd buy a commercial one.