380 Introduction to Electrical Power and Power Electronics
thyristor current, once switched on, must be forcefully switched off (commutated)
to cease conduction. Therefore, a converter using thyristors as the switching devices
must incorporate an additional commutating circuit—a signicant part of the
inverter—for the converter performance. There are two main types of inverters: the
line commutated and the force commutated.
Line-commutated inverter. This type of inverter must be connected to the ac
system into which it feeds power. The design method is matured and has
been extensively used in high-voltage dc transmission line inverters. The
inverter is simple and inexpensive and can be designed in any size. The
disadvantage is that it acts a ...