A THYRISTORIZED SATURABLE REACTOR WITH SELF-EXCITATION

In this paper, a variable reactor suitable for voltage control of resi stive loads is presented. The proposal gives the desired impedance var iation using two naturally commutated thyristor switches in conjunctio n with three-limb magnetic circuit. Load voltage can be controlled by varying the thyristor firing angles and accordingly the DC flux level in the magnetic circuit. The effective impedance is smoothly varied wi th no need for external DC excitation. It is shown that the proposed v oltage control method is accompanied by high power factor and lower ha rmonic content in the supply current. An equivalent circuit for the de vice is deduced from which analytical results are obtained. Theoretica l and experimental results of a prototype are compared and shown to be of satisfactory agreement.