I.V. Sviridova1, O.N. Chirkov2, I.V. Ostroumov3

1-3 FSBEI of HE “Voronezh State Technical University” (Voronezh, Russia)

1 ri-ss-ka@mail.ru; 2 chir_oleg@mail.ru, 3vanik07@mail.ru;

Problem statement. At low load currents, the reverse-pass converter operates in the burst current mode (DCM), which leads to an increase in the amplitude of output voltage ripples and the appearance of parasitic ringing. The traditional solution, increasing the inductance, contradicts the requirements of miniaturization and increasing power density. Cores with a uniform gap are sharply saturated when the threshold current is exceeded, causing nonlinear distortion. Thus, it is required to develop a simple and technologically advanced method for storing the continuous operation mode (CCM) of a reverse-pass converter over the entire load range.

Goal. To experimentally confirm the effectiveness of using a ferrite core with a stepped air gap to prevent a reverse-pass converter from switching to a burst current mode under minimal load.

Results. A method for stabilizing a reverse-pass converter is considered, in which the standard core is replaced by a core with a step gap made by laser cutting. An engineering methodology for calculating the geometry of the gap is given. The technology of manufacturing a core sample with a stepped gap is described (the depth of the first stage is ~0.1 mm, the area of the stage is 1/2 of the initial area). Waveforms of the converter's operation with the original and modified core were obtained in four characteristic modes, which showed that under conditions of minimum input voltage and minimum load, the original core operates in DCM, while the modified core retains CCM; at all other operating points (maximum load and voltage), the converter also remains in CCM.

Practical significance. The developed technique makes it possible to create compact reverse-pass converters with improved weight and size due to the rejection of the traditional increase in the inductance of the primary winding, which is especially important for modern low-power and medium-power electronics. The use of cores with a stepped air gap ensures stable operation of the converter in continuous current (CCM) mode at minimum and zero loads, significantly reducing voltage ripples and suppressing parasitic high-frequency ringing. The proposed engineering algorithm for calculating gap geometry makes it possible to purposefully design power supplies that are resistant to a wide range of input voltages and load currents.

Sviridova I.V., Chirkov O.N., Ostroumov I.V. Method of stabilization of a reverse-pass converter using a ferrite core with a stepped air gap // Radiotekhnika. 2026. V. 90. № 7. P. 51−56. DOI: https://doi.org/10.18127/j00338486-202607-09

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