Zero-voltage transition–zero-current transition pulsewidth modulation DC–DC buck converter with zero-voltage switching–zero-current switching auxiliary circuit

Abstract

In this study, a new zero-voltage transition (ZVT) -zero-current transition (ZCT) quasi-resonant buck converter, which ensures zero crossings at any time required for soft switching (SS) and provides ZVT turn-on and ZCT turn-off together for the main switch of active snubber cell in buck converter is presented. The proposed circuit combines the most of the advantageous features of the circuits presented previously and overcomes most of drawbacks of these circuits by using only one auxiliary switch with fewer other components. Consequently, new ZVT -ZCT quasi-resonant buck converter, which is verified by a prototype of a 0.4-kW and 100-kHz circuit, is analysed in detail. All semiconductor devices operate under SS, the main switch is subjected to no additional voltage and current stresses, and the stress on the auxiliary switch is very low in the proposed new converter.

Zero-Voltage-Transition Synchronous DC-DC Converters with Coupled Inductors

“…However, the auxiliary switch in [1], [2], [11]- [13] needs a floating gate drive because the source terminal of the auxiliary switch is not in common with the input voltage source ground, thereby resulting in complexity of the gate drive circuit. The other ZVT technique is applied in [14]- [18] where coupled inductors are used. In [14]- [17], the auxiliary inductor is coupled with the main converter inductor, and the leakage inductor is used as the resonance inductor.…”

“…In [17], the auxiliary switch is also turned off under a hard switching condition. In [18], a separate core is needed for the coupled inductor, thereby resulting in too many auxiliary elements. The auxiliary switch in [14]- [18] needs floating gate drive circuit.…”

A Simple Structure of Zero-Voltage Switching (ZVS) and Zero-Current Switching (ZCS) Buck Converter with Coupled Inductor

“…While some auxiliary components are normally added to the converter to obtain quasi-resonant circuits, such as switches, diodes, inductors, capacitors and so on. In [4], [5], the loss of main switch is decreased by the quasi-resonant circuits, but some additional elements work under hard-switching conditions, which generate a large amount of power losses. Therefore, it is not obvious that the total efficiency of the converters has improved.…”

A ZVT–ZCT PWM synchronous buck converter with a simple passive auxiliary circuit for reduction of losses and efficiency enhancement

“…Because of its low additional conduction losses and its operation which almost replicates as of PWM converters, the soft-switching techniques have allured the attention in the recent times [18][19][20]. In ZVT-ZCT converters [19][20][21][22][23][24] generally the auxiliary switch actuates just before the main switch is made active and culminates after it is executed.…”