Citation: Miranda-Terán, E.M.; Tofoli, F.L.; Torrico Bascopé, G.V.; Torrico Bascopé, R.P. Modified Active-Clamped Current-Fed DC–DC Push–Pull Converter. Energies 2023, 16, 6300. https://doi.org/10.3390/ en16176300 Academic Editor: Gianluca Brando Received: 31 July 2023 Revised: 23 August 2023 Accepted: 28 August 2023 Published: 30 August 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). energies Article Modified Active-Clamped Current-Fed DC–DC Push–Pull Converter Eldin Mario Miranda-Terán 1 , Fernando Lessa Tofoli 2 , Grover Victor Torrico Bascopé 3 and Rene Pastor Torrico Bascopé 1, * 1 Department of Electrical Engineering, Federal University of Ceará, Fortaleza 60020-181, Brazil; eeldin@yahoo.com 2 Department of Electrical Engineering, Federal University of São João del-Rei, São João del-Rei 36307-352, Brazil; fernandolessa@ufsj.edu.br 3 Huawei Sweden Technologies AB, 164 94 Kista, Sweden; grover.torrico@huawei.com * Correspondence: rene@dee.ufc.br Abstract: This work presents a modified version of the current-fed dc–dc push–pull converter associated with an active clamping circuit for mitigating voltage spikes on the primary-side switches. Unlike the traditional push–pull topology, saturation due to asymmetrical gating signals applied to the active switches is not likely to occur in the high-frequency transformer because the converter allows for connecting a blocking capacitor in series with the primary winding. In addition, the leakage inductance will not cause high voltage spikes on the primary-side semiconductors owing to the clamping capacitors. Since all active switches operate under the zero-voltage switching (ZVS) condition, one can obtain a high efficiency over a wide load range when comparing the structure with its hard-switching counterpart. Experimental results obtained from a laboratory prototype rated at 1 kW are presented and discussed to validate the theoretical claims. Keywords: active clamping; dc–dc converters; galvanic isolation; push–pull converter; three-state switching cell 1. Introduction Isolated dc–dc converters are often employed in many practical applications that demand a wide voltage conversion range and galvanic isolation [1]. Among several topologies available in the literature for this purpose, the conventional dc–dc push–pull converter represents a simple solution that does not require isolated drivers, but the possible core saturation due to flux imbalance is of major concern [2]. Another important issue is that the voltage stresses on the active switches of the primary side are somewhat high, whereas the reverse recovery current through the secondary-side diodes causes high switching losses during turn-off in both voltage-fed and current-fed converters [3]. The aforementioned drawbacks motivated the development of distinct approaches in terms of topological modifications and modulation techniques. For instance, the authors in [4] combined the push–pull converter and the three-state switching cell (3SSC), which in turn was formerly introduced in [5]. A blocking capacitor is connected in series with one of the windings that constitute the autotransformer of the 3SSC to eliminate the dc bias and avoid saturation. In turn, the dual inductor current-fed push–pull converter described in [6] relies on a modified switching strategy so that the primary-side switches operate under soft-switching conditions during turn-on and turn-off. The authors in [7] propose a modified topology that can increase efficiency significantly when compared with its hard-switching counterpart. However, a detailed loss breakdown shows that the overall conduction losses in the active switches increase significantly. The modified current-fed push–pull converter in [8] requires fewer components than other Energies 2023, 16, 6300. https://doi.org/10.3390/en16176300 https://www.mdpi.com/journal/energies