3-phase 1800 mode VSI
In 1800 mode VSI each thyristor conduct for 1800 and two thyristor are fired at 600 interval. For example if thyristor T1 is fired at 00 then it will conduct for 00 to 1800 and next thyristor T2 will fine at 600 table 2.4 explains the period of conduction and firing angle of each thyristor.