阅读说明：本技术 一种可实现短路保护的自激推挽式变换器及短路保护方法 (Self-excitation push-pull type converter capable of realizing short-circuit protection and short-circuit protection method ) 是由 梁乒 曾令前 于 2019-11-27 设计创作，主要内容包括：本发明公开了一种可实现短路保护的自激推挽式变换器及短路保护方法,变换器的变压器包括环状的磁芯、输入绕组、输出绕组和启动绕组,输入绕组、输出绕组和启动绕组均绕制在环状的磁芯上,输入绕组和输出绕组互不重叠交叉,启动绕组与输入绕组重叠绕制,且与输出绕组互不重叠交叉；或者,启动绕组绕制分布在输入绕组和输出绕组之间,输入绕组和启动绕组均不与输出绕组重叠交叉。本发明可以降低启动电容的容值,提高自激推挽式变换器的带容性负载的能力,并且在短路状况下,保持较低的短路工作电流,长期进行短路保护。(The invention discloses a self-excitation push-pull converter capable of realizing short-circuit protection and a short-circuit protection method, wherein a transformer of the converter comprises an annular magnetic core, an input winding, an output winding and a starting winding, wherein the input winding, the output winding and the starting winding are wound on the annular magnetic core, the input winding and the output winding are not overlapped and crossed, the starting winding is wound with the input winding in an overlapped manner, and the starting winding and the output winding are not overlapped and crossed; or the starting winding is wound and distributed between the input winding and the output winding, and the input winding and the starting winding are not overlapped and crossed with the output winding. The invention can reduce the capacitance value of the starting capacitor, improve the capacity with capacitive load of the self-excitation push-pull converter, keep lower short-circuit working current under the condition of short circuit, and carry out short-circuit protection for a long time.)

1. A self-excited push-pull converter for realizing short-circuit protection, which comprises a resistor R1 connected to the input end of the converter, a starting capacitor C2, and a transformer, wherein the transformer comprises a ring-shaped magnetic core, an input winding, an output winding and a starting winding, the input winding, the output winding and the starting winding are wound on the ring-shaped magnetic core, the self-excited push-pull converter is characterized in that,

the input winding and the output winding are not overlapped and crossed, the starting winding is wound with the input winding in an overlapping mode, and the starting winding and the output winding are not overlapped and crossed; or the starting winding is wound and distributed between the input winding and the output winding, and the input winding and the starting winding are not overlapped and crossed with the output winding;

the starting capacitor C2 takes a value of 22nF, and the resistor R1 takes a value of 1.2K ohm to 1.5K ohm.

2. A self-excited push-pull converter according to claim 1, wherein one end of the resistor R1 is connected to the input terminal of the converter, the other end of the resistor R1 is connected to one end of the start capacitor C2, and the other end of the start capacitor C2 is grounded; or, one end of the resistor R1 is connected to the input end of the converter, one end of the starting capacitor C2 is connected to the input end of the converter, and the other end of the resistor R1 is connected to the other end of the starting capacitor C2 and connected to the starting winding.

3. A self-excited push-pull converter according to claim 1, wherein when the start winding is wound overlapping with the input winding, the input winding and the output winding are distributed on the magnetic core to occupy 180 degrees each.

4. A self-excited push-pull converter according to claim 1, wherein when the start winding and the input winding are wound in overlapping relation, the input winding is distributed over the magnetic core at 90 degrees and the output winding is distributed over the magnetic core at 270 degrees, or the input winding is distributed over the magnetic core at 270 degrees and the output winding is distributed over the magnetic core at 90 degrees.

5. A short-circuit protection method for a self-excited push-pull converter, said converter comprising a resistor R1 connected to the converter input, a starting capacitor C2, and said transformer comprising a toroidal core, an input winding, an output winding and a starting winding, characterized in that the steps of said short-circuit protection method are as follows:

s1, winding the input winding and the output winding on the magnetic core, wherein the input winding and the output winding are not overlapped and crossed;

s2, winding the starting winding on the magnetic core, wherein the starting winding is overlapped with the input winding and is not overlapped and crossed with the output winding;

s3, setting the value of the starting capacitor C2 to be 22nF, and setting the value of the resistor R1 to be 1.2K ohm to 1.5K ohm;

or, the short-circuit protection method comprises the following steps:

s1, winding the input winding and the output winding on the magnetic core, so that the input winding and the output winding do not overlap and cross each other;

s2, winding the starting winding on the magnetic core, wherein the starting winding is positioned between the input winding and the output winding, and the input winding and the starting winding are not overlapped and crossed with the output winding;

s3, setting the starting capacitor C2 to be 22nF, and setting the resistor R1 to be 1.2K ohm to 1.5K ohm.

6. The short-circuit protection method of claim 5, further comprising connecting one end of the resistor R1 to the input of the converter, the other end of the resistor R1 to one end of the start capacitor C2, and the other end of the start capacitor C2 to ground; alternatively, one end of the resistor R1 is connected to the input terminal of the inverter, one end of the start capacitor C2 is connected to the input terminal of the inverter, and the other end of the resistor R1 is connected to the other end of the start capacitor C2 and connected to the start winding.

7. The short-circuit protection method according to claim 5, wherein the input winding and the output winding are distributed on the magnetic core to occupy 180 degrees each when the start winding and the input winding are wound in overlapping relation.

8. The short-circuit protection method according to claim 5, wherein when the start winding and the input winding are wound in an overlapping manner, the input winding is distributed over the magnetic core at 90 degrees and the output winding is distributed over the magnetic core at 270 degrees, or the input winding is distributed over the magnetic core at 270 degrees and the output winding is distributed over the magnetic core at 90 degrees.

Technical Field

The invention relates to the field of self-excitation push-pull converters, in particular to a self-excitation push-pull converter capable of realizing short-circuit protection and a method for realizing short-circuit protection by using the converter, which can reduce the size of a starting capacitor, can realize long-term short-circuit protection, reduce short-circuit current and improve the capacity of a load with a capacitor.

Background

The main forms of the circuit structure of the existing self-excited push-pull converter are a Royer circuit and a self-oscillation Jensen circuit. The Royer circuit can realize short-circuit protection of an output end load by optimizing a circuit design, as described in patent document with publication number CN102291001A, however, in the prior art, leakage inductance of a transformer needs to be adjusted when short-circuit protection is realized, if a value of a load side capacitor is too large, transmission efficiency of the transformer is reduced, and a circuit cannot be started, which limits capacity of the converter with the capacitor load, and if working current of the circuit is made large in order to improve capacity of the converter with the capacitor load, power consumption of the converter is increased, and components are burned, and it is seen that similar prior art has poor compatibility between a short-circuit protection function and capacity with the capacitor load.

Patent document CN102543371A discloses a transformer structure, in which a magnetic pillar extends from the outer surface of a closed magnetic core, two windings of a common mode inductor are wound on a ring-shaped magnetic core, and a winding of a differential mode inductor is wound on the magnetic pillar, and the transformer structure is designed to reduce the temperature rise of a magnetic integrated device during short-circuit protection, and cannot realize long-term short-circuit protection, reduce starting capacitance, and improve the capacity of a load with capacitance while reducing short-circuit current.

Patent document CN102710110A discloses a short-circuit protection method for a self-excited push-pull converter, which adopts a commonly used Royer circuit structure, and in this document, the leakage inductance of the transformer is adjusted by means of artificial short-circuit, and the capacity of the starting capacitor is increased to 1uF, although the short-circuit operating current can be reduced, the capacity of the transformer with capacitive load is still insufficient, and can only reach 470uF, and the increase of the starting capacitor will result in the increase of the cost.

It can be seen that the self-excited push-pull converter of the prior art has the following disadvantages:

1. short-circuit protection cannot be realized, or the short-circuit working current is large, continuous short circuit cannot be realized, otherwise, the switch tube is easy to burn;

2. in order to reduce the short-circuit working current and increase the capacitance value of the starting capacitor, the capacitance value of the starting capacitor is larger, and the raw material cost is higher;

3. the capacity with the capacitive load is weaker, and if the capacitive load is forcibly increased, poor starting can be caused, and the switching tube is burnt.

Disclosure of Invention

The invention aims to provide a self-excitation push-pull type converter capable of realizing short-circuit protection and a protection method thereof, which can overcome the defects of the existing short-circuit protection of the self-excitation push-pull type converter, reduce the capacitance value of a starting capacitor on the premise of not increasing components, improve the capacity with capacitive load of the self-excitation push-pull type converter, keep lower short-circuit working current under the condition of short circuit and carry out short-circuit protection for a long time.

The purpose of the invention is realized by the following technical scheme:

a self-excited push-pull converter for realizing short-circuit protection, which comprises a resistor R1 connected to the input end of the converter, a starting capacitor C2, and a transformer, wherein the transformer comprises a ring-shaped magnetic core, an input winding, an output winding and a starting winding, the input winding, the output winding and the starting winding are wound on the ring-shaped magnetic core, the self-excited push-pull converter is characterized in that,

the input winding and the output winding are not overlapped and crossed, the starting winding is wound with the input winding in an overlapping mode, and the starting winding and the output winding are not overlapped and crossed; or the starting winding is wound and distributed between the input winding and the output winding, and the input winding and the starting winding are not overlapped and crossed with the output winding;

the starting capacitor C2 takes a value of 22nF, and the resistor R1 takes a value of 1.2K ohm to 1.5K ohm.

Furthermore, one end of the resistor R1 is connected to the input end of the converter, the other end of the resistor R1 is connected to one end of the starting capacitor C2, and the other end of the starting capacitor C2 is grounded; or, one end of the resistor R1 is connected to the input end of the converter, one end of the starting capacitor C2 is connected to the input end of the converter, and the other end of the resistor R1 is connected to the other end of the starting capacitor C2 and connected to the starting winding.

Further, when the start winding and the input winding are wound in an overlapping mode, the input winding and the output winding are distributed on the magnetic core to occupy 180 degrees respectively.

Further, when the start winding and the input winding are wound in an overlapping manner, the input winding occupies 90 degrees on the magnetic core, the output winding occupies 270 degrees on the magnetic core, or the input winding occupies 270 degrees on the magnetic core, and the output winding occupies 90 degrees on the magnetic core.

And a short-circuit protection method for a self-excited push-pull converter, the converter comprising a resistor R1 connected to the converter input, a starting capacitor C2, and a transformer comprising a toroidal core, an input winding, an output winding and a starting winding, characterized in that the short-circuit protection method comprises the steps of:

s1, winding the input winding and the output winding on the magnetic core, wherein the input winding and the output winding are not overlapped and crossed;

s2, winding the starting winding on the magnetic core, wherein the starting winding is overlapped with the input winding and is not overlapped and crossed with the output winding;

s3, setting the value of the starting capacitor C2 to be 22nF, and setting the value of the resistor R1 to be 1.2K ohm to 1.5K ohm;

or, the short-circuit protection method comprises the following steps:

s1, winding the input winding and the output winding on the magnetic core, so that the input winding and the output winding do not overlap and cross each other;

s2, winding the starting winding on the magnetic core, wherein the starting winding is positioned between the input winding and the output winding, and the input winding and the starting winding are not overlapped and crossed with the output winding;

s3, setting the starting capacitor C2 to be 22nF, and setting the resistor R1 to be 1.2K ohm to 1.5K ohm.

Further, the method also comprises the steps of connecting one end of the resistor R1 to the input end of the converter, connecting the other end of the resistor R1 to one end of the starting capacitor C2, and connecting the other end of the starting capacitor C2 to the ground; alternatively, one end of the resistor R1 is connected to the input terminal of the inverter, one end of the start capacitor C2 is connected to the input terminal of the inverter, and the other end of the resistor R1 is connected to the other end of the start capacitor C2 and connected to the start winding.

Further, when the start winding and the input winding are wound in an overlapping mode, the input winding and the output winding are distributed on the magnetic core to occupy 180 degrees respectively.

Further, when the start winding and the input winding are wound in an overlapping manner, the input winding occupies 90 degrees on the magnetic core, the output winding occupies 270 degrees on the magnetic core, or the input winding occupies 270 degrees on the magnetic core, and the output winding occupies 90 degrees on the magnetic core.

Compared with the prior art, the self-excitation push-pull converter optimized according to the invention has the following remarkable technical effects by setting the input winding and the output winding into a winding relation which is not overlapped and crossed mutually and matching with the values of the starting capacitor and the resistor:

1. the self-excitation push-pull converter can directly carry out long-term short-circuit protection without debugging, and after the circuit is recovered, the power supply can automatically work;

2. the capacity of the self-excitation push-pull converter with a capacitive load is remarkably improved, the capacity can reach up to 4700uF, and the problems of poor starting and switch tube burnout are avoided;

3. the capacitance value of the starting capacitor is reduced, and under the same specification, the smaller the capacitance value of the starting capacitor is, the more the price is deviated, and the raw material cost is reduced;

4. the full-load conversion efficiency and the light-load conversion efficiency of the self-excitation push-pull type converter are both obviously improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a circuit configuration of a self-excited push-pull converter according to a first embodiment of the present invention;

fig. 2 is a schematic diagram of a transformer winding structure according to a first embodiment of the invention;

FIG. 3 is a pictorial view of the transformer winding configuration of FIG. 2;

fig. 4 is a circuit configuration of a self-excited push-pull converter according to a third embodiment of the present invention;

fig. 5 is a circuit configuration of a self-excited push-pull converter according to a fourth embodiment of the present invention;

fig. 6 is a circuit configuration of a self-excited push-pull converter according to a fifth embodiment of the present invention.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known structures, systems, devices, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

In order to explain the technical solution of the present invention, the following description is made by referring to the specific embodiments and the accompanying drawings.