Sustained conduction method of controllable reactor of multiple parallel branch type

For the reactor controlled by series bipolar thyristor, taking the mode of multiple parallel inductance branches can restrain the harmonic currents and it is not necessary to install filter elements. This paper studies two types of new trigger systems, one of them, named for simplified sustained conduction method, is suitable to branches with same value of inductances, while the first branch needs to be regulated, the others only play role to sustain the current transferred from first branch. The another is named for compound sustained conduction method, here the values of branch inductances decrease successively, and the later branch is regulated to full conduction after sustenance of former branch current; this method can further restrain the harmonic current or diminish the quantity of parallel branches.