CN107895636A - A kind of flat surface transformer of the I type half turn windings of leakage-adjustable inductance - Google Patents

Abstract

The invention relates to a planar transformer with an I-type half-turn winding with adjustable leakage inductance, comprising an E-type magnetic core, an I-type magnetic core, a primary winding, secondary windings W1-W4, a rectifier tube D1‑D4 and a filter capacitor C1 ~C4; the primary winding is wound on the side column and the middle column of the E-shaped magnetic core, and the four I-shaped windings of the secondary winding are stacked in two windows respectively; each I-shaped winding is One end is grounded through the rectifier tube, one end is grounded through the filter capacitor, or each I-type winding is connected to the output through the rectifier tube at one end, and the other end is connected to the output through the filter capacitor; the E-type magnetic core and the I-type magnetic core are snapped together; among them, the same The two I-type windings in the window, the port grounded by the capacitor and the port grounded by the rectifier tube are located on the same side. The invention enables the secondary winding to be equivalent to 0.5 turns, so that the number of turns of the primary side can be reduced to half that of one turn of the secondary side, greatly reducing the winding volume and processing difficulty of the transformer, and improving the power density.

Description

A Planar Transformer with Adjustable Leakage Inductance I-type Half-turn Winding

technical field

The invention relates to a planar transformer with an I-type half-turn winding with adjustable leakage inductance, which belongs to the field of electromagnetic technology.

Background technique

Due to its small size, planar transformers are often used in applications that require high power density. Among them, the LLC resonant converter is widely used in high-end power supplies and busbar converters because of its easy realization of soft switching, high efficiency and power density.

The LLC resonant converter generally includes a front-stage full-bridge/half-bridge inverter circuit, a resonant capacitor, a resonant inductor, a transformer and a secondary rectification and filtering circuit. LLC resonant converters are often used in applications with large voltage transformation ratios such as 400V to 12V, so the transformer transformation ratio can reach 16 or higher.

For topologies such as the LLC resonant converter, in order to reduce its volume, the transformer generally adopts a planar transformer structure, and the window area of the planar transformer is relatively small. For a transformer with a high transformation ratio, since the secondary side of the conventional winding method is at least one turn, for a transformer with a transformation ratio of 16, the minimum number of turns on the primary side is 16 turns. Excessive number of turns on the primary side may lead to insufficient window area of the transformer to wind a high-side ratio transformer, or affect the space of the secondary winding, making it impossible to use a secondary winding with a larger cross-section, which limits the capacity of the transformer.

Contents of the invention

The invention provides a planar transformer with an I-type half-turn winding with adjustable leakage inductance, which is used to solve the problem of too many turns of the primary winding of a planar transformer with a large transformation ratio used in LLC resonant converters and other occasions and the problem of insufficient window area .

The technical solution of the present invention is: a planar transformer with adjustable leakage inductance I-type half-turn winding, including E-type magnetic core, I-type magnetic core, primary winding, secondary winding W1~W4, and rectifier tubes D1-D4 And filter capacitors C1~C4;

The primary winding is wound on the side column and the middle column of the E-shaped magnetic core, and the four I-shaped windings of the secondary winding are stacked in two windows respectively; each I-shaped winding is one end through The rectifier tube is grounded, and one end is grounded through the filter capacitor, or each I-type winding is connected to the output through the rectifier tube at one end, and the other end is connected to the output through the filter capacitor; the E-type magnetic core and the I-type magnetic core are snapped together; among them, the The two I-type windings, the port grounded by the capacitor and the port grounded by the rectifier are located on the same side.

Each of the I-type windings is grounded through a rectifier tube at one end and grounded through a filter capacitor at one end, specifically:

In the secondary winding, the upper port of W1 is grounded through capacitor C1, and the lower port is grounded through rectifier D3; the upper port of W2 in the secondary winding is grounded through rectifier D1, and the lower port is grounded through capacitor C3; the upper port of W3 in the secondary winding is grounded through capacitor C2 Grounded, the lower port is grounded through the rectifier tube D4; the upper port of W4 in the secondary winding is grounded through the rectifier tube D1, and the lower port is grounded through the capacitor C4; the upper port of W1W3 and the lower port of W2W4 are connected in parallel as positive output.

Each of the I-type windings is output through a rectifier tube at one end, and output through a filter capacitor at one end, specifically:

In the secondary winding, the upper port of W1 is connected to the output terminal through the capacitor C1, and the lower port is connected to the output terminal through the rectifier tube D3; the upper port of W2 in the secondary winding is connected to the output terminal through the rectifier tube D1, and the lower port is connected to the output terminal through the capacitor C3; In the winding, the upper port of W3 is connected to the output end through the capacitor C2, and the lower port is connected to the output end through the rectifier tube D4; the upper port of W4 in the secondary winding is connected to the output end through the rectifier tube D1, and the lower port is connected to the output end through the capacitor C4; the upper port of W1W3 Connect to the ground in parallel with the lower port of W2W4.

The E-type magnetic core includes side columns M1, M3, and middle column M2; the primary side winding is wound on the side columns M1, M3 and the middle column M2 of the E-type magnetic core, and the winding turns on the side columns and the middle column are changed Distribution to adjust the size of the leakage inductance; the winding direction of the side column is opposite to that of the middle column, and the winding direction of the two side columns is the same.

The change of winding turns distribution on the side column and the middle column to adjust the leakage inductance is specifically: adding one turn of the middle column winding, and correspondingly reducing the two side column windings by one turn, which can ensure that the excitation inductance remains unchanged and reduce the leakage inductance; Adding one turn each of the two side column windings corresponds to reducing one turn of the center column winding, which can increase the leakage inductance while keeping the excitation inductance unchanged.

The rectifier is a diode or a controllable device.

The beneficial effects of the present invention are:

Using standard magnetic cores, a higher transformation ratio can be achieved without constant value, which reduces the difficulty of winding processing of high transformation ratio planar transformers; the reduction in the number of turns allows the use of windings with larger cross-sections, thereby increasing the current carrying capacity of the windings; relatively Compared with other half-turn transformers, the structure of the present invention is symmetrical, each half-winding works alternately to form a complete loop, and there is no magnetic bias problem; the outlet is simple and can be easily connected to the rectifier and filter circuit of the circuit part; so that the secondary winding can wait The efficiency is 0.5 turns, so the number of turns of the primary side can be reduced to half of that of one turn of the secondary side, which greatly reduces the winding volume and processing difficulty of the transformer, and improves the power density.

Description of drawings

Fig. 1 is the schematic diagram of secondary structure of the present invention;

Fig. 2 is the schematic diagram of the primary side structure of the present invention;

Fig. 3 is the structural representation of embodiment 1;

Fig. 4 is a schematic structural diagram of embodiment 2.

Detailed ways

Embodiment 1: As shown in Figure 1-3, a planar transformer with I-type half-turn winding with adjustable leakage inductance, including E-type magnetic core, I-type magnetic core, primary winding, secondary winding W1~W4, Rectifier tubes D1-D4 and filter capacitors C1~C4;

The primary winding is wound on the side column and the middle column of the E-shaped magnetic core, and the four I-shaped windings of the secondary winding are stacked in two windows respectively (W1, W2 are stacked on the side column M1 Between M2 and the center column, W3 and W4 are stacked between M2 and M3; stacking can be stacked up and down, or stacked side by side, as shown in Figure 3; for stacking W1 and W2 up and down overlap up and down, W3 and W4 overlap up and down, so it is not shown in the figure); one end of each I-type winding is grounded through a rectifier tube, and one end is grounded through a filter capacitor; among them, the two I-type windings in the same window are grounded through a capacitor The port of the rectifier and the port grounded by the rectifier are located on the same side.

Further, each of the I-type windings can be set to have one end grounded through a rectifier tube and one end grounded through a filter capacitor, specifically as shown in Figure 3:

In the secondary winding, the upper port of W1 is grounded through capacitor C1, and the lower port is grounded through rectifier D3; the upper port of W2 in the secondary winding is grounded through rectifier D1, and the lower port is grounded through capacitor C3; the upper port of W3 in the secondary winding is grounded through capacitor C2 Grounded, the lower port is grounded through the rectifier tube D4; the upper port of W4 in the secondary winding is grounded through the rectifier tube D1, and the lower port is grounded through the capacitor C4; the upper port of W1W3 and the lower port of W2W4 are connected in parallel as positive output.

The E-type magnetic core includes side columns M1, M3, and middle column M2; the primary side winding is wound on the side columns M1, M3 and the middle column M2 of the E-type magnetic core, and the winding turns on the side columns and the middle column are changed distribution to adjust the leakage inductance; the winding direction of the side column is opposite to the winding direction of the middle column, and the winding direction of the two side columns is the same (in Figure 2, the winding direction of the two side columns is clockwise, and the winding direction of the middle column direction is counterclockwise).

Further, it can be set to change the distribution of winding turns on the side column and the middle column to adjust the leakage inductance, specifically: increase one turn of the middle column winding, and correspondingly reduce the two side column windings by one turn, so that the excitation inductance can be guaranteed to remain unchanged At the same time, the leakage inductance is reduced; adding one turn of each of the two side column windings corresponds to reducing one turn of the middle column winding, which can ensure that the excitation inductance remains unchanged and increase the leakage inductance.

Further, the rectifier is set as a MOS tube controllable device (as shown in FIG. 3 ).

Embodiment 2: As shown in Figure 1-2 and Figure 4, a planar transformer with an I-type half-turn winding with adjustable leakage inductance, including an E-type magnetic core, an I-type magnetic core, a primary winding, and a secondary winding W1 ~W4, rectifier tubes D1-D4 and filter capacitors C1~C4;

The primary winding is wound on the side column and the middle column of the E-shaped magnetic core, and the four I-shaped windings of the secondary winding are stacked in two windows respectively; each I-shaped winding is one end through The rectifier tube is connected to the output, and one end is connected to the output through the filter capacitor; the E-type magnetic core and the I-type magnetic core are snapped together; among them, the two I-type windings in the same window, the port grounded by the capacitor and the port grounded by the rectifier tube are located at the same side.

Further, each of the I-type windings can be set to have one end connected to the output through a rectifier tube, and one end connected to the output through a filter capacitor, specifically as shown in Figure 4:

In the secondary winding, the upper port of W1 is connected to the output terminal through the capacitor C1, and the lower port is connected to the output terminal through the rectifier tube D3; the upper port of W2 in the secondary winding is connected to the output terminal through the rectifier tube D1, and the lower port is connected to the output terminal through the capacitor C3; In the winding, the upper port of W3 is connected to the output end through the capacitor C2, and the lower port is connected to the output end through the rectifier tube D4; the upper port of W4 in the secondary winding is connected to the output end through the rectifier tube D1, and the lower port is connected to the output end through the capacitor C4; the upper port of W1W3 Connect to the ground in parallel with the lower port of W2W4.

The E-type magnetic core includes side columns M1, M3, and middle column M2; the primary side winding is wound on the side columns M1, M3 and the middle column M2 of the E-type magnetic core, and the winding turns on the side columns and the middle column are changed Distribution to adjust the size of the leakage inductance; the winding direction of the side column is opposite to that of the middle column, and the winding direction of the two side columns is the same.

Further, it can be set to change the distribution of winding turns on the side column and the middle column to adjust the leakage inductance, specifically: increase one turn of the middle column winding, and correspondingly reduce the two side column windings by one turn, so that the excitation inductance can be guaranteed to remain unchanged At the same time, the leakage inductance is reduced; adding one turn of each of the two side column windings corresponds to reducing one turn of the middle column winding, which can ensure that the excitation inductance remains unchanged and increase the leakage inductance.

The rectifier is a diode (as shown in Figure 4).

Working principle of the present invention is:

As shown in Figure 1, when the upper port of W1W3 and the lower port of W2W4 are connected in parallel as positive output, the principle is as follows:

For the primary winding structure with adjustable leakage inductance:

The primary winding is wound on the side column and the center column at the same time, and the contributions of the winding on the side column and the winding on the center column to the leakage inductance are considered respectively. For the winding column on the side column, because relatively more parts of its magnetic force lines are closed by the surrounding air, more magnetic flux leakage is generated, which contributes greatly to the leakage inductance of the primary winding. As for the winding on the central column, because it is surrounded by two side columns, most of its magnetic field lines are closed by the magnetic core, so the magnetic flux leakage generated is relatively small, and the contribution to the leakage inductance of the primary winding is small. Therefore, when we change the turns distribution of the middle column and the side column, the total leakage inductance of the primary winding can be adjusted. At the same time, it should be noted that the magnetic force lines generated by the winding on the center column of each turn are equal to the magnetic force lines generated by each turn of the two side columns.

For a half-turn secondary winding configuration:

When working, the primary side winding is fed with alternating current, which generates alternating magnetic flux in the magnetic core, and the secondary side induces current to offset the magnetic flux generated by the primary side current. Assume that the primary side is fed with a sinusoidal alternating current.

Assuming that in the positive half cycle, the direction of the magnetic field lines in the magnetic column M2 is perpendicular to the surface of the paper and the strength gradually increases, then in order to offset the increase of the magnetic flux, a clockwise current will form in the winding composed of W1-W4. , but for the clockwise current, the rectifier tubes D2 and D3 are in the cut-off state, so only W1W4 has current passing through. At this time, the voltage of the upper port of W1 and the lower port of W4 is positive, and they are connected in parallel as output.

Then in the negative half cycle, the direction of the magnetic force line in the magnetic column M2 is perpendicular to the paper surface and its strength gradually increases. In order to offset the increase of the magnetic flux, there will be a counterclockwise current in the winding composed of W1~W4. Trend, but because the rectifier tube D1D4 is in the cut-off state, only the current flows through W2W3. At this time, the voltage of the lower port of W2 and the upper port of W3 are positive, and they are connected in parallel as the output.

It can be seen from the above analysis that in a complete cycle, the four windings are turned on alternately, which always ensures that the output voltage of the parallel connection of the upper port of W1, the lower port of W4, the lower port of W2 and the upper port of W3 is positive. At the same time, in each half cycle, the output voltage is the parallel output of two half-turn coils, so the actual voltage of the tap is the voltage induced by the half-turn coil, thus realizing the structure of the half-turn coil.

As shown in Figure 4, when the upper port of W1W3 and the lower port of W2W4 are connected in parallel as the ground, the principle is as follows:

For the primary winding structure with adjustable leakage inductance:

The primary winding is wound on the side column and the center column at the same time, and the contributions of the winding on the side column and the winding on the center column to the leakage inductance are considered respectively. For the winding column on the side column, because relatively more parts of its magnetic force lines are closed by the surrounding air, more magnetic flux leakage is generated, which contributes greatly to the leakage inductance of the primary winding. As for the winding on the central column, because it is surrounded by two side columns, most of its magnetic field lines are closed by the magnetic core, so the magnetic flux leakage generated is relatively small, and the contribution to the leakage inductance of the primary winding is small. Therefore, when we change the turns distribution of the middle column and the side column, the total leakage inductance of the primary winding can be adjusted. At the same time, it should be noted that the magnetic force lines generated by the winding on the center column of each turn are equal to the magnetic force lines generated by each turn of the two side columns.

For a half-turn secondary winding configuration:

When working, the primary side winding is fed with alternating current, which generates alternating magnetic flux in the magnetic core, and the secondary side induces current to offset the magnetic flux generated by the primary side current. Assume that the primary side is fed with a sinusoidal alternating current.

Assuming that in the positive half cycle, the direction of the magnetic field lines in the magnetic column M2 is perpendicular to the surface of the paper and the strength gradually increases, then in order to offset the increase of the magnetic flux, there will be a clockwise current in the winding composed of W1~W4. , but because of the clockwise current, the rectifier tubes D1 and D4 are in the cut-off state, so only W2W3 has current passing through. At this time, the upper port of W2 and the lower port of W3 are at high potential, and the rectifier tubes are connected in parallel as output.

Then in the negative half cycle, the direction of the magnetic force line in the magnetic column M2 is perpendicular to the paper surface and its strength gradually increases. In order to offset the increase of the magnetic flux, there will be a counterclockwise current in the winding composed of W1~W4. Trend, but because the rectifier tube D2D3 is in the cut-off state, only the current flows through W1W4. At this time, the lower port of W1 and the upper port of W4 are at high potential, and the rectifier tubes are connected in parallel as output.

It can be seen from the above analysis that in a complete cycle, the four windings are turned on alternately, which always ensures that the lower port of W1, the upper port of W4, the upper port of W2 and the lower port of W3 are at high potential. After the rectifier tubes are connected in parallel, they can be used as Positive output. At the same time, in each half cycle, the output voltage is the parallel output of two half-turn coils, so the actual voltage of the tap is the voltage induced by the half-turn coil, thus realizing the structure of the half-turn coil.

The specific implementation of the present invention has been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned implementation, and within the knowledge of those of ordinary skill in the art, it can also be made Various changes.

Claims (6)

1. A kind of 1. flat surface transformer of the I type half turn windings of leakage-adjustable inductance, it is characterised in that：It is former including E-type magnetic core, I type magnetic cores Side winding, vice-side winding W1 ~ W4, rectifying tube D1-D4 and filter capacitor C1 ~ C4；

   The primary side winding is wound on the side column and center pillar of E-type magnetic core, and four I types windings of vice-side winding stack respectively two-by-two Among two windows；Each I type windings are the rectified pipe ground connection in one end, the filtered capacity earth in one end, or each I types Winding is that the rectified pipe in one end connects output, and the filtered electric capacity in one end connects output；E-type magnetic core and I types magnetic core fasten；Wherein, together Two I type windings in one window, the port of port and rectified pipe ground connection through capacity earth are located at homonymy.
2. 2. the flat surface transformer of the I type half turn windings of leakage-adjustable inductance according to claim 1, it is characterised in that：It is described every Individual I types winding is the rectified pipe ground connection in one end, the filtered capacity earth in one end, is specially：

   W1 upper ports are grounded through electric capacity C1 in vice-side winding, the rectified pipe D3 ground connection of lower port；W2 upper ports pass through in vice-side winding Rectifying tube D1 is grounded, and lower port is grounded through electric capacity C3；W3 upper ports are grounded through electric capacity C2 in vice-side winding, the rectified pipe of lower port D4 is grounded；The rectified pipe D1 ground connection of W4 upper ports, lower port are grounded through electric capacity C4 in vice-side winding；Wherein W1, W3 upper port and W2, W4 lower port are in parallel to be exported as positive pole.
3. 3. the flat surface transformer of the I type half turn windings of leakage-adjustable inductance according to claim 1, it is characterised in that：It is described every Individual I types winding is that the rectified pipe in one end connects output, and the filtered electric capacity in one end connects output, is specially：

   W1 upper ports connect output end through electric capacity C1 in vice-side winding, and the rectified pipe D3 of lower port connects output end；W2 in vice-side winding The rectified pipe D1 of upper port connects output end, and lower port connects output end through electric capacity C3；W3 upper ports connect through electric capacity C2 in vice-side winding Output end, the rectified pipe D4 of lower port connect output end；The rectified pipe D1 of W4 upper ports connects output end, lower port warp in vice-side winding Electric capacity C4 connects output end；Wherein W1, W3 upper port and W2, W4 lower port earth.
4. 4. the flat surface transformer of the I type half turn windings of leakage-adjustable inductance according to claim 1, it is characterised in that：The E types Magnetic core includes side column M1, M3, center pillar M2；Primary side winding is wound on side column M1, M3 and center pillar M2 of E-type magnetic core, changes side Umber of turn is distributed to adjust leakage inductance size on post, center pillar；Direction of winding and center pillar direction of winding are on the contrary, two side columns on side column Direction of winding is identical.
5. 5. the flat surface transformer of the I type half turn windings of leakage-adjustable inductance according to claim 4, it is characterised in that：It is described to change Umber of turn, which is distributed to adjust leakage inductance size, on change side column, center pillar is specially：Increase by a circle center pillar winding, it is corresponding to reduce by two sides Each circle of post winding, it can guarantee that magnetizing inductance is constant while reduce leakage inductance；Increase each circle of two side column windings, in corresponding reduction The circle of post winding one, can guarantee that and increase leakage inductance while magnetizing inductance is constant.
6. 6. the flat surface transformer of the I type half turn windings of leakage-adjustable inductance according to claim 1, it is characterised in that：It is described whole Flow tube is diode or controllable devices.