CN101202507A

CN101202507A - New type phase shifting full bridge soft switch converter

Info

Publication number: CN101202507A
Application number: CNA2007101925692A
Authority: CN
Inventors: 李云
Original assignee: Zhuzhou CSR Times Electric Co Ltd
Current assignee: Zhuzhou CRRC Times Electric Co Ltd
Priority date: 2007-12-11
Filing date: 2007-12-11
Publication date: 2008-06-18

Abstract

The invention provides a novel phase-shift full-bridge soft switch converter, comprising a first transformer, a second transformer, a rectifier circuit, a filter circuit, a capacitor branch, a lagging bridge arm and a leading bridge arm. The capacitor branch, the lagging bridge arm and the original winding of the first transformer form a half-bridge topology structure; the original winding of the first transformer, the original winding of the second transformer, the lagging bridge arm and the leading bridge arm form a full-bridge topology structure; the conduction time of an upper switch and a lower switch of a left bridge arm is a half period; the rectifier circuit and the filter circuit are sequentially connected behind the auxiliary winding of the first transformer 1 and the second transformer. The invention has the advantages of small corrugation, high conversion efficiency and implementing zero voltage switch in the whole load range.

Description

A kind of new type phase shifting full bridge soft switch converter

Technical field

The present invention relates to a kind of soft switch circuit, particularly a kind of new type phase shifting full bridge soft switch converter.

Background technology

The process of turning on and off of regular tap is accompanied by the acute variation of voltage and current, produces bigger switching loss and switching noise, and therefore soft switch produces.So-called soft switch is exactly that switching device terminal voltage in opening process is very little, and its electric current is also very little in turn off process, and the power loss of this switching process is little, is referred to as soft switch.The soft switch of conventional transducers is to utilize inductance and electric capacity to come the switch track of switch is carried out shaping, generally be to adopt to diminish buffer circuit and realize, from the angle of energy, it is switching loss to be transferred to buffer circuit consume, thereby improves the switch condition of switching tube.This method does not improve the conversion efficiency of converter, even just efficient decreases.

Summary of the invention

The purpose of this invention is to provide a kind of new type phase shifting full bridge soft switch converter, it does not adopt and diminishes buffer circuit, can reduce switching loss, but not the transfer of switching loss can realize zero voltage switch in whole loading range.

It comprises the first transformer Tr1, the second transformer Tr2, rectification circuit 1, filter circuit 2 and:

At least a capacitive branch 3 that constitutes by two electric capacity;

At least a lagging leg 4 that constitutes by two switch elements;

At least a leading-bridge 5 that constitutes by two switch elements;

Capacitive branch, lagging leg and the former limit of first transformer Tr1 winding constitute a half-bridge topology; The former limit of described first transformer Tr1 winding, the former limit of second transformer Tr2 winding, lagging leg and leading-bridge constitute a full-bridge topologies, and the left brachium pontis ON time of switch up and down is a half period;

Rectification circuit, filter circuit are connected in turn after the secondary winding of the first transformer Tr1 and the second transformer Tr2.

Switching tube on the lagging leg is operated on the fixing operating frequency and the work pulsewidth is fixed.The high frequency transformer Tr2 that is attached thereto is operated in the half-bridge mode, its input voltage is half of input voltage, power output is only for exporting the part of gross power, so the exciting curent of Tr2 can be amplified in the suitable scope, so that realize zero voltage switch with capacitor resonance in parallel on the lagging leg switching tube, therefore the zero voltage switch of the switching tube on the lagging leg and load are irrelevant, so whole converter can realize zero voltage switch in whole loading range.

Description of drawings

Fig. 1 is a schematic block circuit diagram of the present invention;

Fig. 2 is circuit theory diagrams of the present invention.

Embodiment

As shown in Figure 1 and Figure 2, it comprise the first transformer Tr1, the second transformer Tr2, rectification circuit 1, filter circuit 2 and:

At least a capacitive branch 3 that constitutes by two electric capacity;

At least a lagging leg 4 that constitutes by two switch elements;

At least a leading-bridge 5 that constitutes by two switch elements;

Specifically, wherein switch element can be thyristors such as MOSFET, IGBT or IPM, VD2, VD3, VD4, VD5 are the crystal diodes of these switch elements, and C3, C4, C5, C6 are that the economize on electricity of corresponding switch element is perhaps economized on electricity and held capacity summation with parallel connection outside electric capacity.

Left side brachium pontis is a lagging leg, and right brachium pontis is a leading-bridge.Left side brachium pontis and two electric capacity in the left side (two electric capacity are very big, can regard two voltage sources as), transformer Tr1 constitutes a half-bridge topology; Left and right sides brachium pontis and transformer Tr2 constitute a full-bridge topologies, and the left brachium pontis ON time of switch up and down is half period (Dead Time is ignored).

And the switching tube on the lagging leg is operated on the fixing operating frequency and the work pulsewidth is fixed.The high frequency transformer Tr2 that is attached thereto is operated in the half-bridge mode, its input voltage is half of input voltage, power output is only for exporting the part of gross power, so the exciting curent of Tr2 can be amplified in the suitable scope, so that realize zero voltage switch with capacitor resonance in parallel on the lagging leg switching tube, therefore the zero voltage switch of the switching tube on the lagging leg and load are irrelevant, so whole converter can realize zero voltage switch in whole loading range.

Turn on and off the phase place of signal by regulating right brachium pontis and left brachium pontis, realize the adjusting of voltage.

In switching process, a switching tube (being assumed to be S4) of leading arm turn-offs in advance, because the shunt capacitance on the switching tube exists, the voltage on the switching tube slowly rises, thereby realizes the no-voltage shutoff.After this capacitor resonance on the leakage inductance of high frequency transformer Tr1, outputting inductance and the leading arm, voltage on the S4 continues rising value DC power supply voltage, and the voltage on the S3 reduces to 0, and open S3 this moment, thereby the no-voltage that realizes the switching tube on the leading arm turns on and off.S1 on the lagging leg turn-offs then, and the reason same with S4 can realize the no-voltage shutoff.After this leakage inductance of high frequency transformer Tr1 and Tr2 and the capacitor resonance on the lagging leg, the voltage on the S1 continues to rise to DC power supply voltage, and the voltage on the S2 reduces to 0, opens S2 this moment, thus the no-voltage that realizes the switching tube on the lagging leg turns on and off.Because output inductor is very big, the switching tube on the leading arm almost all can be realized zero voltage switch in full-load range.Its lagging leg zero voltage switch mainly realizes by the exciting current of transformer Tr1 and transformer Tr2, and is almost irrelevant with load.Therefore the zero voltage switch of this converter is almost irrelevant with load, can realize the Zero-voltage soft switch in the gamut.Be to reduce losing of duty ratio, the leakage inductance of two transformers is obtained smaller, therefore, the increase of the exciting current of transformer Tr2 can not cause losing of duty ratio, and the increase of the exciting current of transformer Tr1 can cause that the switch conduction loss increases.In order to reduce duty-cycle loss, avoid causing too much turn-on consumption, the exciting current of transformer Tr2 is obtained bigger, the exciting current of the second transformer Tr2 is obtained the exciting current of transformer Tr1 and the leakage inductance of two transformers smaller greater than the exciting current of the first transformer Tr1.Because output voltage equals the secondary voltage value sum of transformer Tr1 and transformer Tr2, when two transformer secondary voltages and vanishing, voltage on the switch S 1 has been taken a part away, after former limit is by the secondary clamper, voltage on the S1 is not Vin, but be lower than Vin, the no-voltage that realizes the lagging leg switching tube is opened be more prone to.Because two transformers transmit energy simultaneously, the ripple of the output voltage of this circuit is also very little, and output inductor can design very for a short time like this, thereby has reduced the volume of design cost and converter.

Secondary adopts the pattern of two rectifier bridge series connection, and rectification circuit 1 comprises the rectifier bridge of two series connection, and the input port of each rectifier bridge links to each other with the secondary winding of the described first transformer Tr1, the second transformer Tr2 respectively.This on the one hand can export two different voltages easily simultaneously, 24V as shown in FIG. and 110V, the output when no-load voltage ratio that also can design two transformers in the practical application according to actual needs realizes two different voltages.On the other hand, two rectifier bridge series connection can be avoided the electric current circulation of the former secondary of transformer, improve conversion efficiency.

Claims

1. new type phase shifting full bridge soft switch converter, it comprise first transformer (Tr1), second transformer (Tr2), rectification circuit (1), filter circuit (2) and:

At least a capacitive branch that constitutes by two electric capacity (3); At least a lagging leg that constitutes by two switch elements (4); At least a leading-bridge that constitutes by two switch elements (5);

The former limit winding that it is characterized in that described capacitive branch (3), lagging leg and first transformer (Tr1) constitutes a half-bridge topology; The former limit winding of described first transformer (Tr1), the former limit of second transformer (Tr2) winding, lagging leg and leading-bridge constitute a full-bridge topologies, and the left brachium pontis ON time of switch up and down is a half period;

Described rectification circuit (1), filter circuit (3) are connected in turn after the secondary winding of first transformer (Tr1) and second transformer (Tr2).

2. a kind of new type phase shifting full bridge soft switch converter as claimed in claim 1, it is characterized in that described rectification circuit (1) comprises the rectifier bridge of two series connection, the input port of each rectifier bridge links to each other with the secondary winding of described first transformer (Tr1), second transformer (Tr2) respectively.

3. as a kind of new type phase shifting full bridge soft switch converter of claim 1 or 2, it is characterized in that described switch element comprises MOSFET.

4. as a kind of new type phase shifting full bridge soft switch converter of claim 1 or 2, it is characterized in that described switch element comprises IGBT.

5. as a kind of new type phase shifting full bridge soft switch converter of claim 1 or 2, it is characterized in that described switch element comprises IPM.

6. as a kind of new type phase shifting full bridge soft switch converter of claim 1 or 2, it is characterized in that the exciting current of the exciting current of described second transformer (Tr2) greater than first transformer (Tr1).