This paper aims to present the principle of virtual air gap inductance and the design of a voltage regulation device based on this principle. The authors provide a comprehensive analysis of this specific application that consists of locally saturating the magnetic circuit of the voltage regulator to modify its global properties. This saturation is created by a direct current flowing in a small auxiliary coil inserted in the specific area of the magnetic circuit to saturate this zone.
Analytical calculation and finite elements simulations are used to optimize the device for a specific application tied to the supply of electrical ovens in metallurgic usage. Experimental results are presented at the end of the paper.
The experimental results presented in this paper are in concordance with the analytical calculation and with the finite element simulations for different operation points. The difficulty of the study of the virtual air gap comes mainly from the nonlinearity of the phenomena because the principle is based on a local and controllable saturation of the magnetic circuit.
The originality of the paper concerns the introduction of virtual air gap principle in a specific industrial application.
