Interleaved two-transistor forward converter with phase-shift control

Abstract

The invention is an interleaved two-transistor forward converter with phase-shift control. The converter includes a first transformer primary winding Lt1, a second transformer primary winding Lt2 anda transformer secondary winding Lt3, which are connected in parallel and share the same magnetic core. The turn ratio of the three windings is n: n: 1. A transformer secondary side rectifier unit is arectifier bridge composed of four diodes. The dotter terminal of the transformer secondary winding Lt3 is connected to the midpoint of one bridge arm of the rectifier bridge, and the undotted terminal is connected to the midpoint of the other bridge arm of the rectifier bridge. A filter capacitor C0 and a load R0 are connected in parallel with each other, connected in series with a freewheel inductor L0 and connected in parallel with a rectifier unit. L0>>Lr / n. Only one magnetic core is used, and the two primary windings are wound on the magnetic core and coupled to each other. Forward and reverse excitation of the magnetic core of the transformer realized, the utilization ratio of the magnetic core is improved, the power density of the converter is improved, and the volume of the outputfilter is reduced. Moreover, the circuit structure of the secondary winding side is optimized, and the topological reliability is improved.

Description

technical field [0001] The invention relates to the technical field of converters, in particular to an interleaved parallel double-transistor forward converter with phase shift control. Background technique [0002] People have applied a variety of communication methods in different fields to promote human development. The stability of the power supply system is the key to ensure the safe and reliable operation of various communication control systems. Once a failure occurs, the communication line will be interrupted and the system will be paralyzed, causing huge economic losses to the society. The communication power structure consists of PFC, isolated DC-DC stage and DSP controller. The second part of the isolation stage DC-DC converts the voltage DV 400V to a low-level DC 48V, realizing a high step-down ratio. Considering the requirements of the phase-shifted full-bridge structure and the LLC resonant structure for high efficiency, low cost and soft switching performan...

AI Technical Summary

Problems solved by technology

[0004] The problems of the topology in the above literature are that the transformer cores of the two converters in the parallel double-terminal forward conversion topology are unidirectionally magnetized, the utilization rate of the cores is not high, the volume of the converter is large, and the cost is relatively high. It is not conducive to the integration of the circuit, and the literature does not consider the loss of the secondary side duty cycle caused by the external resonant inductance of the primary side

Images