A simple model predicts small-signal control loop behavior of magamp post-regulator

A block diagram approach is used to provide an insight into magamp feedback control operation. The analysis reveals a pole-shifting phenomenon inherent in the type-A loop transfer function. A procedure for calculating the gain and open-loop poles in the control loop of each reset circuit is given. The procedure also shows how to compensate the error amplifier for stable operation. The detailed example of a 50 kHz magamp is given; however, the validity of the model has been demonstrated experimentally at 100 kHz. With a factor of two included in the Faraday's law block, the model describes loop behavior for a magamp with two saturable reactors for symmetrical topology.<
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