For steady-state conditions, the voltage × time product applied to the magnetizing inductance, over a complete Cycle, must equal zero. volt × time product is V IN × D × Ts, where D is the on time duty cycle (D) and Ts is the switching period. The off period is defined as (1-D) × Ts. The voltage across the primary when the main switch is off is: V C – V IN . Where V C is the clamp voltage. Setting the equality:
V IN × D × Ts = (V C – V IN ) × (1-D) × Ts solving for V C = V IN /(1-D).
The Saturable Reactor consists of two core and coil assemblies each with two AC coils and two DC coils.
Two assemblies are required to avoid inducing AC voltage into the DC circuitry. The DC winding provides the ‘variable-saturation' of the cores and so forces the AC reactance of the assembly to change. It is made of M6 Grain Oriented Steel laminations/ or square B-H lamination as desired by the application and Nomex insulated copper windings. Together with the linear reactor the saturable reactor provides part of a variable voltage divider, which effectively slides the output voltage up and down, effectively providing voltage regulation.