Zero-Voltage-Switching Auxiliary Circuit for Minimized Inductance Requirement in Series-Resonant DC/DC Converter Systems

Improved ZVS Criterion for Series Resonant Converters

“…However, the charge-based criterion is only partly accurate since the output capacitor of the switches is mostly regarded as being discharged by a constant current source. On the contrary, for the energy-based criterion, the energy in the output capacitor of the MOSFETs should be fully released during the dead time [7]- [9]. The energybased criterion takes into account the energy balance of all components in the circuit, hence, it is considered more accurate than the charge-based ZVS criterion [10]- [13].…”

“…There has been three fallacies in the conventional way of using ZVS criterion in resonant converters. First, the energybased criterion used for non-resonant converters is directly applied to resonant converters without rigorous verification [7]- [9]. Therefore, the question of accuracy of the energybased ZVS criterion used in the resonant converter remains unanswered.…”

“…However, the charge-based criterion has been used to determine the ZVS condition, resulting in inaccuracies in the ZVS condition formula and the dead time calculations. Second, the ZVS conditions and the dead time required for ZVS completion may be entirely different for different modulation strategies, which have not been considered in previous studies [7]- [9], [14]. Third, most previous work has assumed that the energy stored in the resonant tank inductor is zero at the end of the dead time [9], [11], [12].…”

“…Second, the ZVS conditions and the dead time required for ZVS completion may be entirely different for different modulation strategies, which have not been considered in previous studies [7]- [9], [14]. Third, most previous work has assumed that the energy stored in the resonant tank inductor is zero at the end of the dead time [9], [11], [12]. However, this assumption makes the ZVS criterion inaccurate.…”

An efficient soft switching synchronous buck converter for battery charging application in hybrid electric vehicle architecture

“…Additionally, the design requires complex control circuitry. Paper 12 uses a series resonant circuit in addition to auxiliary circuit to achieve ZVS conditions with PCB integrated inductance, which has more losses compared to the conventional wound inductor. To achieve soft switching condition of bidirectional DC-DC converter (BDC), [13][14][15] the converter is operated in critical current mode (CRM) thereby achieving the ZVS condition and eliminating diode reverse-recovery phenomenon without additional auxiliary circuitry.…”