Explain the three phase 120 degree mode VSI.
Three phase 120 degree mode VSI:
In the 120-degree mode voltage source inverter, each thyristor conducts for 120 degree of a cycle. 120-degree mode VSI required six steps, each step of 60 degree duration for completing one cycle of output AC voltage. During each step, only two thyristors will conduct, one thyristor will conduct from the upper group and one thyristor will conduct from lower group.