Design of a square loop magnetic integrating device

The problem investigated in this research was the development of a static integrating circuit applicable to closed loop feedback control systems. Investigation of various methods of attack indicated that square loop magnetic cores offered characteristics required for the integration process. These include the ability to sum input information and the ability to store information for an indefinite period of time. An experimental program was carried out, investigating the various properties of square loop magnetic materials and required design parameters. Through this work it was verified that the process of integration could be realized by using the partial switching volt-second absorption characteristics of such a core. Basic operation of the developed system is as follows. The heart of the system is a multi-apertured square loop core sometimes called a Cyclops core. The signal to be integrated is sampled over a period of time. Following each sample interval a constant voltage pulse is generated, the width of which is proportional to the average signal voltage over the sample interval. The polarity of this pulse is that of the signal. These pulses are applied to the input winding of the Cyclops core, each pulse integrating the core flux to a new value. A magnetic relaxation oscillator is coupled to the Cyclops core via a minor aperture. The frequency of this oscillator is a function of the flux level in the core and thus also of the integral of the input signal. By this method constant read out is possible without destroying the flux level. The frequency of the read out oscillator is transformed to a voltage level by a-magnetic frequency converter following the read out oscillator. The system is completely static employing only square loop magnetic cores and semiconductor devices. A complete model of the proposed system was designed, built, and tested. To demonstrate its application the system was employed as a series element in the loop of an analogued voltage regulating feedback control system. In this thesis the basic concept of integration is developed in terms of the partial switching volt-second absorption characteristics of square loop cores. Generalized system equations and the overall transfer function are developed and presented…. Design of each circuit of the integrator system is carried out on a first order approximation basis. Rigorous design criteria are not developed due to the complexity involved in the nonlinear cases. Various gain constants are predicted on the basis of these approximate design methods. Results of experimental determination of the various parameters are compared with those predicted and the differences discussed. Waveforms from the actual circuit are shown. Results of this work indicate that the proposed system should find wide application in the feedback servo field --Abstract, pages 2-3