Nonlinearity of static characteristics of contactless wide-band high-current converters of electric power control and management systems

Abstract

The paper presents the general principles of construction of contactless ferromagnetic converters of large direct currents and their basic requirements. Developing one of the developed wide-range magnetic modulation contactless converters of monitoring and control systems concerning powerful pumping stations of water supply and land reclamation and large electric power facilities is shown. The developed converter differs from the known ones in a wide range of controlled currents, increased accuracy and sensitivity, technological design and small weight and dimensions. Determining the static characteristics of contactless wide-range magnetic modulation converters and the degrees of nonlinearity of their static characteristics are considered. The degrees of nonlinearities of the family of static characteristics of a magnetic modulation contactless converter and its optimal static characteristics are obtained and investigated. It is shown that the minimum degree of nonlinearity of the family of static characteristics of 10.3% corresponds to the optimal static characteristic of the converter at a modulation value of 1.65. The expression of the degree of nonlinearity of the optimal static characteristic of a magnetic modulation contactless converter is obtained. It is shown that for a given limit of the controlled value of 0.7, the value of the degree of nonlinearity is 5.2%. The developed magnetic modulation contactless converter can be widely used in monitoring and control systems in land reclamation and irrigation, in water supply, industry, railway transport, metallurgy, science, technology, as well as for checking electric meters at the place of their installation for contactless monitoring of direct and alternating currents.