Magnetic amplifier analysis and application using block-diagram techniques

THE SYNTHESIS of feedback-control systems incorporating magnetic amplifiers has long been hampered by the lack of a really satisfactory way in which to represent the transfer function of the self-saturating magnetic amplifier. Approximations, such as those which represent the magnetic amplifier as being characterized by a volts-per-ampere-turn gain and an L-R time constant, are normally unsatisfactory in anything but the simplest system. In addition, there is a need for a single theory of operation which will bridge the existing gap between the analyses of the conventional magnetic amplifier and those of the “half-cycle response” circuits. It is intended that this paper will fill these needs with an analysis utilizing block-diagram techniques. The use of the block diagram is not only compatible with the usual methods of synthesizing feedback-control systems, but also provides an insight into the mechanics of magnetic amplifier operation which heretofore has been lacking.