Basic Characteristics of Orthogonal-Core-Type Variable Inductor with Permanent Magnets

Variable inductors, which consist of magnetic cores, primary dc windings, and secondary ac windings, can control the effective inductance of the secondary ac windings by the primary dc current due to the magnetic saturation effect. Therefore, they can be used as reactive power compensators in electric power systems. This paper presents a novel orthogonal-core-type variable inductor in which permanent magnets are inserted in the magnetic path of the primary dc flux. The proposed variable inductor can generate an arbitrary reactive power when the primary dc current is zero, and it can control the effective reactive power from lead to lag by changing the primary dc current from positive to negative.