Электромагнитный преобразователь с пространственно-периодическим полем для систем многопараметрового контроля

Abstract

В работе рассмотрена проблема контроля параметров металлических изделий при воздействии на них электромагнитного поля индукционных установок. В качестве датчика рассмотрен электромагнитный преобразователь с пространственно-периодической структурой поля, представляющий собой соленоид на немагнитном полимерном каркасе с контролируемым объектом в форме протяженного цилиндрического ферромагнитного сердечника. Показано, что такой датчик позволяет бесконтактно измерять электропроводность, магнитную проницаемость и геометрические параметры металлических изделий.This paper considers the problem of providing the optimal operating mode of induction units, for which it is necessary to ensure the matching of the frequency converter and, its complex load – inductor. A peculiarity of the system "inductor-heated object" is the dependence of its resonant frequency, Q-factor and impedance on the conductivity and permeability of this object, which, in turn, are functions of temperature. The most dramatic changes in specified parameters are taking place when the heated object is ferromagnetic material and its temperature goes up through Curie point. The purpose of the report is to study the possibility of using eddy current transducers with a spatially periodic field structure to monitor the parameters of a heated sample. Eddy current transducers are widely used in measurement and non-destructive testing in flaw detection, material structure research, coating thickness determination, and for other tasks. The paper proposes a transducer model with spatially periodic structure of the electromagnetic field, using which one can place the measuring windings so that the output signal of the converter would contain information about the parameters of several harmonics. In this case, the amplitude and phase of each spatial harmonic is to be considered an independent informative parameter. The result of the research is an algorithm providing contactless measurement of the conductivity, magnetic permeability and diameter of a cylindrical sample, which is based on the values of amplitudes and phases of spatial harmonics obtained by calculation. Transducer that follows certain requirements to the design can be used at high temperatures and in the zone of strong electromagnetic fields.