I am helping a group of my friends for writing microcontroller code for their final year project in EE. They are building a small model of HVDC system (fed from 3 phase supply), with microcontroller based converter and inverter. We are done with the coding for firing of the SCRs in the converter (it is line commutated SCR converter). Now, for the inverter stage, which one should we use? VSI or CSI? I know that the line commutated converter is also called as 'current source converter'. Does that mean we should use a CSI? What is done in practice?