Hmmm, methinks you do not know what "LCI" stands for do you? LCI stands for Line Commutated Inverter. So you are asking "How does a line commutated line commutated inverter work?"
Do a web search of Line Commutated Inverter. In fact, I have posed on that subject myself in this forum at least a couple of times I can think of. The search function is your friend.
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** All I every really wanted to be, was... A LUMBERJACK!.**