Electr Eng DOI 10.1007/s00202-017-0632-1 ORIGINAL PAPER Modeling and implementation of a new ZCS interleaved bidirectional buck–boost DC–DC converter for energy storage systems Pramod Kumar Aylapogu 1 · Veera Venkata Subrahmanya Kumar Bhajana 1,2 · Pavel Drabek 2 · Martin Jara 2 Received: 20 December 2016 / Accepted: 24 July 2017 © Springer-Verlag GmbH Germany 2017 Abstract This paper deals with a new soft-switched inter- leaved bidirectional DC–DC converter for energy storage systems. The conventional interleaved bidirectional con- verter incorporates with an additional auxiliary circuit to attain soft turn-on operation of the main switching devices (IGBTs). The proposed converter is operated in boost and buck modes with zero current switching turn-on operation in order to have minimized turn-on losses by adding auxil- iary switches, inductor and capacitors to the main interleaved converter module. The proposed interleaved converter has advantages like reduced switching power losses, device count and improved efficacy. The operating principles and theoreti- cal analysis of the interleaved topology under buck and boost modes are presented in detail. Design simulation analysis and its experimental results were executed using 1-kW, 50-kHz laboratory prototype. The converter’s soft-switching charac- teristics and its performance were also demonstrated. Keywords Buck · Boost · Bidirectional · Zero current switching (ZCS) · DC–DC List of symbols V C b Voltage of auxiliary capacitor C b i S 2 Current of the switch S 2 B Veera Venkata Subrahmanya Kumar Bhajana kumarbvvs@yahoo.co.in; bvvs.kumarfet@kiit.ac.in; kumarbvv@rice.zcu.cz 1 School of Electronics Engineering, KIIT University, Bhubaneswar 751024, Odisha, India 2 Regional Innovation Centre for Electrical Engineering, University of West Bohemia, Univerzitni 26, 30614 Pilsen, Czech Republic i S b Current of the auxiliary switch S b L x Equivalent inductance L a and L b Auxiliary inductors C b and C a Auxiliary capacitors k Constant V o Load voltage I m Maximum input inductor current P o Output power V 1 Input voltage (boost mode) V 2 Input voltage (buck mode) 1 Introduction Energy storage systems of hybrid electric vehicles are essen- tial in recent years. The non-isolated bidirectional DC–DC converters play an important role in battery charging in buck and discharging in boost modes. The main problems in designing the bidirectional converters (BDCs) are switching losses and efficiency demand. To overcome these problems the soft-switched interleaved bidirectional DC–DC con- verter with zero voltage switching [1] was obtained through high efficiency for low switching frequency. A ZVS/ZCS interleaved DC–DC converter topologies [2, 3] were also developed with multi-phases, where the auxiliary switch and capacitors were used in order to obtain soft-switching opera- tions. This may increase the auxiliary devices count and cost of the converter topology. A high voltage conversion ratio for the four-phase interleaved converter [4] with zero current switching operations have been obtained by the inclusion of auxiliary circuits separately for each converter module, and also, it increases the auxiliary device count usage in whole converter topology. A low-power, low-voltage three- phase three-level DC–DC converter with flying capacitor technology [5] has been developed to avoid short-circuit 123