Soft switching resonance BUCK converter adopting pulse width modulation control

Abstract

The invention relates to the field of switching power supplies, in particular to a soft switching resonance BUCK converter adopting pulse width modulation control. According to the converter, on the basis of a traditional BUCK converter, two diodes and one resonant capacitor are added, and a pulse width modulation mode is adopted, so that the soft switching of all switching devices can be realized. The converter is composed of an input filter capacitor, a BUCK converter upper tube, a BUCK converter lower tube, a BUCK converter inductor and an auxiliary diode upper tube, an auxiliary diode lower tube, a resonance capacitor and an output filter capacitor; by virtue of the converter, zero voltage switching of the BUCK converter upper and lower tubes can be realized; and meanwhile, the zero-current switching of the two auxiliary diodes can be realized. In addition, a control mode adopted by the converter is the pulse width modulation mode, so that the converter is easy to control, and a special controller is not needed.

Description

technical field [0001] The invention relates to the field of switching power supplies. The invention proposes a soft-switching resonant BUCK converter controlled by pulse width modulation. The converter adopts a pulse width modulation mode and can realize soft switching of all switching tubes. Background technique [0002] BUCK converter is the most basic and widely used power converter circuit in the field of switching power supply. In the discipline of power electronics technology, there are a large number of patented technologies and scientific documents that analyze and discuss the soft switching technology of BUCK circuits, and propose many solutions. There are two mainstream ways to realize the soft switching of BUCK converters. One uses a combination of multiple passive devices to provide soft switching conditions for the main switching device of BUCK by using auxiliary inductors and capacitors. The other uses auxiliary switching tubes and The combination of inducto...

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Problems solved by technology

[0003] The circuit structure of the soft-switching BUCK converter using a combination of multiple passive components is complex, and due to the existence of the resonant circuit, when the converter is working in the process of transient changes such as on-off, over-current, and short-circuit, the soft-switching condition disappears and the stress Problems such as exceeding the standard have created difficulties for the optimal design of the circuit and actual product application

[0004] The soft-switching BUCK converter that uses the combination of auxiliary switching tubes, inductors, and capacitors usually has a simple circuit structure and relatively stable circuit characteristics; however, in order to realize the soft switching of the main switching device, it is necessary to add an auxiliary switching tube and provide control of the auxiliary switching tube. A special controller must be used, or an auxiliary control circuit must be added, which increases the workload of product design and creates difficulties for the promotion of technical solutions

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