Zero voltage switch full-bridge direct-current converter with diode and auxiliary transformer clamping

Abstract

The invention provides a zero voltage switch full-bridge direct-current converter with a diode and an auxiliary transformer clamping. In the invention, mainly based on a full-bridge direct-current converter comprising a direct-current power supply Vin, a first contravariant bridge arm, a second contravariant bridge arm, a resonance inductor, a clamping circuit, an isolation transformer and a rectification and filtering circuit, an auxiliary transformer and an auxiliary clamping circuit are added. The auxiliary transformer can effectively reduce current flowing over a lamping diode and an auxiliary clamping diode and improve working environment of the clamping diode; and meanwhile, since the clamping circuit and the auxiliary clamping circuit are both reversely connected in parallel at thetwo ends of input voltage of the converter, the converter can not be influenced by output voltage in a starting state or an output short-circuit current-limiting state at all; and therefore, the converter can use the voltage of the direct-current power supply Vin to effectively reset the current of the clamping diode no matter in what state and has the advantages of more stable and reliable work,more compact and effective structure, lower cost and the like.

Description

technical field [0001] The invention relates to a converter, in particular to a zero-voltage switching full-bridge DC converter clamped by a diode and an auxiliary transformer, which belongs to a DC conversion device. Background technique [0002] In medium and high power DC conversion occasions, the full bridge converter has been widely used because the switching tube is easy to realize soft switching and adopts constant frequency control. In the past two decades, there have been many soft-switching control strategies and circuit topologies for full-bridge converters. Both the phase-shift control zero-voltage switching full-bridge converter and the phase-shift control zero-voltage zero-current switching full-bridge converter can realize the soft switching of the switching tube. However, whether it is a zero-voltage switching or zero-voltage zero-current switching full-bridge converter, due to the reverse recovery of the secondary rectifier diode, the leakage inductance of ...

AI Technical Summary

Problems solved by technology

The two clamping diodes are turned on alternately in one switching cycle. If the clamping diodes are not turned off fast enough, it is easy to pass through and cause damage to the clamping diodes.

[0005] For this reason, the invention patent "Zero-Voltage Switching Full-Bridge DC Converter Clamped by Diode Plus Current Transformer" with application number 200710019261.8 proposes the method of using current transformer to reduce the current flowing through the clamping diode, making it It quickly decreases to zero, which improves the conversion efficiency, but the output of the current transformer rectification circuit added to the circuit needs to be connected with the pre-submerged auxiliary DC voltage source. If the auxiliary DC voltage source is set separately, the circuit is more complicated; when When the auxiliary DC voltage source is replaced by the output voltage of the converter, the output voltage will be relatively low when the full-bridge converter is in the power-on state or the output short-circuit current-limiting state. At this time, the output voltage of the converter cannot effectively control the clamp diode current for reset

At the same time, if the added current transformer rectification circuit adopts the full-bridge rectification method, four diodes need to be used, which makes the circuit more complicated and increases the production cost

Images