Stabilizing magamp control loop by using an inner-loop compensation

Using an inner-loop compensation scheme, the order of the open-loop transfer function of a magamp control circuit is essentially reduced from two to one for a self-reset scheme. The problem normally associated with compensating a control transfer function with resonance peaking is thereby eliminated. Moreover, if the inner loop gain is designed high enough, the closed-loop gain can be insensitive to the variation of power circuit parameters such as saturable reactor permeability and capacitor equivalent series resistance (ESR). A design example is given to illustrate the step-by-step design procedure for a practical magamp control circuit. The results are verified by loop gain measurements