Bidirectional soft‐switching dc–dc converter for battery energy storage systems

Abstract

The study introduces a bidirectional dc-dc converter with current-and voltage-fed (VF) ports that features soft switching in both buck and boost operating modes. The converter can be used for integration of low-voltage DC sources, such as batteries into a dc bus of considerably higher voltage or a dc link of a grid side inverter. Zero current switching, assisted with the leakage inductance of the isolation transformer, can be achieved at the current-fed side along with zero voltage switching of the VF side, assisted by snubber or intrinsic capacitances of the transistors. Soft switching can be maintained over a wide range of voltage and power levels, regardless of the energy transfer direction. Converter operation is described and theoretical findings were verified with experimental results obtained by means of a 300 W prototype operating at a switching frequency of 100 kHz and designed for integration of a 24 V battery into 400 V dc bus. The converter proposed is compared in terms of efficiency to other competing soft-switching full-bridge topologies implemented with the same components.

Snubberless boost full‐bridge converters: Analysis of soft switching performance and limitations

“…In general, these can be attributed to resonant [22][23][24][25][26][27] and secondary-modulated ones (also referred to as snubberless). [28][29][30][31][32] Although this assumption is not strictly defined and various interpretations are possible, in the present study, the authors assume that clamping in such systems is achieved without a separate dedicated passive or active circuit. Instead, it is achieved with special control principles, by utilizing equivalent inductance and capacitance present in the circuit.…”

“…Considering both L eq and C eq , the output voltage is estimated by The data obtained with (32) are depicted in Figure 9, showing the corresponding changes of the converter gain for various values of C eq , which is linear for all the conditions analysed. With variable duty cycle, the converter can to a certain point negate the influence of L eq and C eq .…”

DC-DC converter with a wide range of providing a natural switching mode at ZVS mode

“…Підвищення енергетичної ефективності силових електронних систем може бути досягнуто за рахунок забезпечення сприятливих умов роботи силових ключів -їх перемикання в режимах нульової напруги або струму (ZVS/ZCS). Для DC/DC перетворювачів з проміжною ланкою змінного струму, одним з підходів, що розглядаються в літературі, є реалізація активного випрямляча з фазовим зсувом, що діє як інвертор струму [1], [2]. Такий підхід дозволяє досягти режиму ZVS ключів інвертора первинної ланки (інвертора напруги) і ZCS випрямних ключів вторин-ної ланки.…”

Modular Battery Charger for Light Electric Vehicles

“…Such applications typically employ a low-voltage battery (24-48 V nominal) and are charged from the AC grid with power up to 1 kW [6][7][8][9][10]. The chargers generally include two-stage ac-dc converters with a power factor pre-regulator (PFP) that is followed by a dc-dc converter [11][12][13] Such systems generally include a DC-bus formed by high voltage (>350 V) electrolytic capacitors [14,15], which are among the most critical parts of power electronic converters in terms of reliability [16].…”