CN1260083A - self-oscillating composite transformer - Google Patents

Abstract

The invention relates to a converter for a self-oscillating oscillator, the periodic conduction of the switching means of which is ensured by a control transformer. The primary of the control transformer is connected in series with an inductor which ensures the transfer of the converted energy to the output load. The device according to the invention comprises a control transformer having an inductance (7d) and the above-mentioned coil windings (7a, 7b, 7c) concentrated on the same magnetic circuit (7) or on respective coupling magnetic circuits, so that the magnetic field generated by said inductance and the magnetic field generated by the primary of said control transformer move in a substantially perpendicular direction. This structure can maintain the inductance (7d) with an excellent overvoltage coefficient. It can be utilized in series or parallel oscillating circuits. This inexpensive arrangement is suitable for all types of converters using a free running oscillator.

Description

self-oscillating composite transformer

The invention relates to the ability to ensure the operation of a self-oscillating oscillator used in an electronic converter structure to keep one or several switching devices used conducting periodically, or to achieve a search between the potential of the input terminal and the potential of the output terminal. suitable for the adjustment of the converter.

Most of such devices used according to the prior art are shown in the accompanying drawings 1 and 2 respectively.

Accompanying drawing 1 here represents the implementation mode that is used the earliest.

Such an implementation of the so-called "blocking oscillator" type uses a semiconductor device 4, the gap existing between its load electrode 4a and its common electrode 4c being used as switching means, capable of passing through the primary 2a wound on the magnetic circuit 2 It is guaranteed to disconnect the current supplied by the power supply connected between the common terminals 1a and 1b.

The periodic conduction of the semiconductor component 4 is ensured by the so-called "reactive" secondary 2b. The secondary is coaxially wound with respect to the primary 2a, and sends an appropriate amplitude and phase to the control electrode 4b of the semiconductor device that can ensure the periodic conduction of the gap between the load electrode 4a and the common electrode 4c. Signal.

Secondary 2c, which is likewise coaxially wound with respect to primary 2a, supplies output load 3 and achieves adjustment of the appropriate potential between common terminals 1a and 1b at the voltage required by load 3.

In particular a capacitor 5 installed in parallel with the terminals of the secondary 2c makes it possible to correct the deleterious effect of the leakage inductance of the magnetic circuit 2 .

For some applications, the size of the capacitor 5 is properly selected, and the overvoltage formed when the frequency of the semiconductor device 4 performing current disconnection and the natural frequency of the oscillating circuit composed of the inductance of the primary 2a and the capacitance of the capacitor 5 is resonant It may be beneficial to run it below.

Using existing devices, it is unrealistic to use such a resonance effect, whether it is a so-called "series connection" or a so-called "parallel connection".

In fact, the energy absorbed by the controlled secondary 2b is strongly coupled to the primary 2a and secondary 2c, causing a large attenuation, resulting in a sudden drop in the overvoltage coefficient Q at resonance.

Under these conditions, the energy absorption of the secondary 2b prevents any noticeable overvoltage from building up across the terminals of the load 3 .

For this reason, in various applications requiring the use of series or parallel resonance, another device is necessary.

Figure 2 here shows this alternative arrangement, certain modifications of which have been described in, inter alia, the Nilssen patents.

In this type of device, the control secondary 2b is replaced by a current converter. The converter is wound on an independent magnetic circuit 6 with its primary 6a and primary 2a wound on the main magnetic circuit 2 mounted in series.

With respect to the secondary 6b wound coaxially with the primary 6a, instead of the secondary 2b, a signal with an appropriate amplitude and phase that can ensure the periodic conduction of the control semiconductor device 4 is sent.

This device prevents any influence of the energy extracted for controlling the switching device 4 on the overvoltage coefficient of the individual coil windings wound on the magnetic circuit 2 by isolating the magnetic circuit of the main transformer 2 from that of the control transformer 6 .

This thus makes it possible to use appropriately the series resonance or the parallel resonance of which the magnetic circuit 2 may be the base.

The disadvantage of such an arrangement is that it involves the addition of a supplementary magnetic circuit 6 and the transformer associated therewith, which greatly increases its cost and the volume of the converter thus assembled.

The device according to the invention makes it possible to avoid the disadvantages encountered in the use of devices constructed according to FIGS. 1 and 2 .

Figure 3 here represents a general implementation of the device described.

If this implementation appears at first glance to be a duplicate of the device shown in Figure 2, this is only superficial, since the two are essentially different.

In fact, if the basic functions of this device continue to be as described above, that is to say, the main transformer wound on the magnetic circuit 2' can ensure good transmission of the energy converted to the output load 3, while the winding on the The associated transformer on the magnetic circuit 6' always controls the periodic conduction of the semiconductor component 4. In contrast, in the arrangement according to the invention shown here, the circuits 2' and 6' are no longer magnetically independent.

Thus, since the circuits 2' and 6' are no longer magnetically independent, they are either coupled, or together altogether.

At this time, it is conceivable that this device has returned to the device shown in Figure 1 in appearance. In this case, the disadvantages mentioned above are once again faced.

In fact, at this point the primary 2'a and 6'a can be considered together and the secondary 6'b corresponds to the secondary 2b.

Not so, because for the device according to the invention to work it is essential that the flux lines generated by the primary 2a of the main transformer move along a trajectory almost perpendicular to the path along which the flux lines generated by the primary 6'b of the additional transformer move.

This means that, on the one hand, the two-phase comparison, the coil windings 2'a and 2'c are coaxially wound on the magnetic circuit 2', and on the other hand, the two-phase comparison, the coil windings 6'a and 6' b is coaxially wound on the same magnetic circuit 2', or on an additional magnetic circuit 6' coupled to the magnetic circuit 2', so that the magnetic flux emitted by each of the transformers thus constituted is almost vertical The directions intersect.

Thus, unlike what occurs in the device shown in Figure 1, if the molecules of the material making up the magnetic circuit 2' and the molecules making up the magnetic circuit 6' are simultaneously excited by the combined magnetic fields of the primary 2'a and 6'a, this The magnetic interaction between the two fields is still negligible because they theoretically cancel each other out due to the normal state of the angles opposite them.

In these cases it is clear that said secondary 6'b of the control transformer can no longer reduce the inductance of any coil winding that can be wound on the magnetic circuit 2', which can be provided by using, for example, and capacitors The possibility of series or parallel resonance of the 5-phase connected inductors is manifested.

FIG. 4 shows a second mode of practical realization of the device according to the invention.

According to this realization, the device, which is the object of the invention, is applied to a converter using the structure of the "capacitive half-bridge" described, the active branch of which consists of two semiconductor devices mounted in series 4' and 4", while its passive branch consists of two capacitors 8a and 8b mounted in series.

The central points 1c and 1d respectively belonging to each of said branches of the bridge circuit are aided by means of the primary 7a comprising the above-mentioned control transformer, the inductor 7d, and a series circuit of capacitor 5' are connected to each other.

The value of the inductance 7d is calculated so that a series oscillating circuit is formed between this inductance and the capacitor 5', the resonant frequency of which is close to the switching frequency of the current reached by the semiconductor devices 4' and 4".

The switch is controlled alternately and periodically by secondary signals 7b and 7c coupled to primary 7a sending a signal of appropriate amplitude and phase to control electrode 4'b and control electrode 4"b respectively.

The circuit can be put into operation if the lines of flux generated respectively by the primary 7a and the inductance 7d are in an almost vertical direction, starting from the application of a voltage to the terminals 1a and 1b, and after starting the oscillation by means not shown here, And send the thus converted energy to the load 3 according to the so-called "energy transfer" mode.

Figure 4a here shows a version of the preceding device. The inductance 7d is connected between the terminals 1e and 1d, is coupled to the secondary 7e, and sends the converted energy to the load 3 in the "voltage transfer" manner described.

A capacitor 5" installed in parallel with the secondary 7e can form a parallel oscillating circuit between the terminals connected to the load 3 and the secondary 7e.

Figure 5 here represents a view from above of a cup 9a joined to a second identical cup capable of forming a magnetic circuit 7 .

The hatching area of this view shows the common joining plane at the two cups. When the cups are installed, a winding bobbin can be inserted into the annular grooves provided for this purpose in the cups.

The cup 9a, like its counterpart, is equipped with a central cylindrical hole 12.

Figure 6 here shows a cross-sectional view of the mounted cups 9a and 9b with hatched areas revealing joined parts and planes.

There is a material gap on the edge of these cups, which can form a large air gap 11, which can improve the overvoltage coefficient Q suitable for the inductor 7d.

Inductor 7d is wound on bobbin 10 mounted between cups 9a and 9b.

In special cases, the air gap 11 can be replaced by a shim which is pressed against the above-mentioned joining plane.

In this way, the inductance 7d manufactured in this way can be combined with the capacitor 5' or 5" to form a series or parallel oscillating circuit, which exhibits excellent overvoltage performance during resonance.

According to this kind of realization, the above-mentioned control transformer and its respective windings 7a, 7b and 7c are suitable for using a toroidal winding method, only needing to pass the insulating wire once or several times across the material forming the cups 9a and 9b Through the cylindrical elongated hole 12.

On Fig. 6, it is found that the windings 7a, 7b and 7c only need to pass once in the elongated hole 12 for the sake of drawing clarity, and then lead to the respective output terminals 4'b and 1c, 1e and 1c, 1b and 4”b will do.

Also here FIG. 5 reveals the part corresponding to the wires of the coil windings 7a, 7b and 7c on the right of the central elongated hole 12. FIG.

The transformer formed in this way is exactly the same as that explained above.

In fact, if Ampere's law is applied, it can be confirmed that the magnetic field generated by the inductance 7d and the magnetic field generated by the primary 7a are obviously perpendicular, and the interaction between the above two magnetic fields is the smallest.

In the case of saturation of the magnetic circuit 7, that is to say when the above-mentioned series or parallel resonance is exhibited, the recorded magnetic phenomenon exhibits a characteristic which is advantageous for the control of the switching means 4' and 4".

In fact, this characteristic of the magnetic material when saturated causes a decrease in the width of the pulses periodically applied to the control electrodes 4'b and 4"b, respectively.

In this extreme case, this would lead to automatic protection of the semiconductor devices 4' and 4" due to the switching off and on between electrodes 4'a and 4'c and between electrodes 4"a and 4"c , a minimal region of voltage/current recovery is observed, making the danger of damage from the described "cross-conduction" phenomenon extremely unlikely.

In addition, if the joint planes of the cups 9a and 9b are required to be properly ground, it can be considered that the coil windings 7a, 7b and 7c constituting the above-mentioned control transformer are then actually wound on a magnetic core without leakage. Alternative periodic switching of the semiconductor components 4 ′ and 4 ″ and a solution for eliminating the described risk of “cross-conduction”.

Figure 7 here represents another implementation of the object device of the present invention.

According to this implementation, the magnetic circuit 2 can be simplified as a single cup body 9a, and its large air gap can further improve the quality factor of the inductor 7d and eliminate its saturation limit.

As for the above-mentioned control transformer, there are no changes except that the magnetic circuit that constitutes it conforms to the monolithic core of the ABCD section that exhibits the least flux leakage.

Figure 8 shows a third implementation of the device for achieving the object of the present invention.

According to this realization, the magnetic circuit 7 consists of a hollow ferrite tube, the cylindrical opening 12' in the center of which allows the passage of the coil windings 7a, 7b and 7c.

In this case, the inductance 7d, whose longitudinal section is marked with a dotted line, is wound in layers onto the outer surface of the ferrite cylinder as tightly connected turns.

This solution is identical to the previous solution in the sense that the inductance 7b formed in this way produces a field which is substantially perpendicular to the field produced by the coil winding 7a.

On the other hand, the inductance 7b thus constituted has an almost infinite air gap which ensures a high quality factor, while the above-mentioned control transformer with its coil windings 7a, 7b and 7c is wound in a rectangle with hatching. A'B'C'D' section on the core.

This implementation is extremely cost-effective, especially for the manufacture of small converters of jetables.

Accompanying drawing 8 shows a kind of realization mode substantially the same as before, difference is only added the ferrite tube 7 ' of second root hollow or solid and connected with tube 7, and for some applications, this tube has again The advantage of magnetic flux being closed to avoid spreading into space.

According to this embodiment, the air gap with respect to the inductance 7d is now determined by the thickness of its coil winding itself.

According to this implementation, assuming that the tube 7' is hollow, it is clear that this tube accommodates the control transformer and its windings 7a, 7b and 7c.

On the other hand, it is also possible to use the cylindrical elongated hole of one or the other of the tubes 7 and 7' in order to form auxiliary inductances which may be required by one or several converters using the device according to the invention.

Accompanying drawing 9 represents a kind of realization mode close to former one.

According to this implementation, a part of the inductor 7d is wound on the tube 7, and a part is wound on the tube 7'.

In this case, the respective conductors 7a, 7b and 7c forming said control transformer pass simultaneously in the central opening of the tube 7 and in the central opening of the tube 7', so that the input and output terminals of these coil windings can be set on the same side.

Obviously, this solution can be extended arbitrarily, and in order to increase the conversion power, some ferrite tubes can be added until they are connected into a bundle of a certain cross-section.

Figure 10 shows a final example of means for achieving the objects of the invention.

This figure shows the right part of a ferrite cylindrical tube corresponding to the magnetic circuit 7 by hatching.

This part shows two elongated holes 14a and 14b extending parallel along the axis of said tube.

As before, the respective wires 7a, 7b and 7c corresponding to the aforementioned control transformers are wound through these cavities.

As for the inductance 7d, it is wound around the outer peripheral surface of the ferrite tube as before, and its right part is exposed, and the right part is represented as an annular region marked with a dotted line here.

The device according to the invention described above makes it possible to remedy the disadvantages of devices built according to the prior art.

In fact, this arrangement gives a good quality factor to the inductor 7d at low cost, without the need to add a control transformer for this to maintain the switching means 4' and 4" alternately and periodically conducting.

On the other hand, it can be integrated on all converters, which requires one or several semiconductor devices.

The device can thus be fully integrated in a semiconductor device of the so-called "fully demagnetized accumulation" and "incompletely demagnetized accumulation" types, the so-called "push-pull", "asymmetrical half-bridge" and "capacitive half-bridge " type of two semiconductor devices, so-called "full bridge" type of four semiconductor devices, and so on in various structures.

Thus, the device according to the invention can be used in a converter configuration requiring at least four switching devices for two-phase operation or three-phase operation in a so-called "full bridge" manner.

The device can be used with all types of semiconductor devices, whether they are so-called bipolar transistors, so-called "MOSFET" transistors mounted in a so-called "common emitter" manner or mounted in a so-called "common base" manner , thyristors, so-called "IGBT" hybrid transistors.

This device also enables a hybrid converter structure combining semiconductor devices with different performances to work normally.

As a matter of course and from the preceding results, the invention is by no means limited to the applications and implementations which have been considered in more detail. Rather, it includes all variations.

Claims (25)

1. An energy conversion device that requires at least one switching device 4' capable of ensuring interruption of the current generated by the power supply connected between the common terminals 1a and 1b through a series circuit comprising, on the one hand There is an inductance 7d from which the converted energy taken out is applied to an output load 3, and on the other hand contains a primary 7a of a control transformer, and one or several secondary sides of the control transformer supply the said one or several The control electrode of a switching device delivers a signal that can ensure its alternate periodic conduction, and is characterized in that the inductance 7d and the primary 7a are respectively wound on the same magnetic circuit or several magnetic circuits that are independent but magnetically coupled, so that The field generated by the inductor 7d and the field generated by the primary 7a meet in the magnetic material in a substantially perpendicular direction. 2. The device as claimed in claim 1, wherein the magnetic circuit 7 is composed of two magnetic material cups 9a and 9b, they form a groove, the skeleton 10 can be inserted, and the inductance 7d is wound on it, Whereas the primary 7a and its one or several associated secondary are loop-wound through a cylindrical opening 12 arranged through said cup. 3. Device according to claim 2, characterized in that an air gap is arranged between the cups 9a and 9b. 4. The device according to claim 2, characterized in that the air gap 11 is arranged only on the periphery of the cups 9a and 9b. 5. A device as claimed in claim 1, characterized in that the magnetic circuit 7 consists only of a cup 9a capable of containing the inductance 7d, while the primary 7a and its one or several associated secondary are ring-shaped The winding passes through a cylindrical opening 12 arranged through said cup. 6. A device as claimed in claim 1, characterized in that the magnetic circuit 7 consists of a hollow tube around which an inductance 7d is wound, while the primary 7a and its associated secondary or secondary are looped It is wound through the cylindrical elongated hole 12 which runs through the said tube. 7. The device according to claim 6, characterized in that a second magnetic tube 7' is connected to the above-mentioned tube constituting the magnetic circuit 7. 8. The device according to claim 7, characterized in that the central elongated hole 12" through the second tube 7' is used as a means for carrying out the toroidal winding associated with the primary 7a and its secondary or secondary aisle. 9. The device according to claim 7, characterized in that a part of the coil winding corresponding to the inductance 7d can be inserted in the second tube 7'. 10. Device according to claims 7, 8 and 9, characterized in that the magnetic circuit 2 is formed by a bundle of magnetic tubes similar to the second tube 7'. 11. A device as claimed in claims 6, 7, 8, 9 and 10, characterized in that the primary 7a and its associated secondary or secondary are wound in a loop, at least through two elongated holes 12 ' and 12". 12. The device according to claims 6, 7, 8, 9 and 10, characterized in that the magnetic material tube constituting the magnetic circuit 7 is provided with at least two axes arranged parallel to the axis of the tube The elongated holes 14a and 14b ensure the toroidal winding of the primary 7a and one or several secondary toroidal windings associated therewith. 13. The device according to claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 is characterized by the fact that the device according to the invention is used in a A switching device 4 is required in the converter configuration. 14. Device according to claims 1, 2, 3, 4, 5, 6, 7, 9, 10, 11 and 12, characterized in that the device according to the invention is used in a On the so-called "push-pull" side, either in a so-called "asymmetrical half-bridge" or in a converter structure with switching means used in a so-called "capacitive half-bridge". 15. Apparatus as claimed in claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12, characterized in that the apparatus according to the invention is used in at least one In a converter configuration of four switching devices used in a so-called "full bridge" for two-phase or three-phase operation. 16. A device as claimed in claims 13, 14 and 15, characterized in that the or each switching means 4' and 4" are so-called "bipolar" transistors mounted in a so-called "common-emitter" manner. 17. A device as claimed in claims 13, 14 and 15, characterized in that the or each switching means 4' and 4" are so-called "bipolar" transistors arranged in a so-called "common base" manner. 18. A device as claimed in claims 13, 14 and 15, characterized in that the or each switching means 4' and 4" are so-called "MOSFET" transistors. 19. A device as claimed in claims 13, 14 and 15, characterized in that the or each switching means 4' and 4" are thyristors. 20. An arrangement as claimed in claims 13, 14 and 15, characterized in that the or each switching means 4' and 4" are so-called "IGBT" semiconductor devices. 21. A device as claimed in claims 13, 14 and 15, characterized in that the or each switching means 4' and 4" are adapted to various types. 22. Apparatus according to each of claims 1 to 21, characterized in that the inductance 7d, in combination with the capacitor 5', forms a series oscillating circuit, between its terminals the converted energy is extracted in a so-called "energy transfer" manner, This energy is sent to the output load 3 . 23. Arrangement according to each of claims 1 to 21, characterized in that a coil winding 7e which supplies power to the output load 3 in a so-called "voltage transfer" manner is coupled to an inductance 7d. 24. The device according to claim 23, characterized in that the coil winding 7e is connected to the capacitor 5" to form a parallel oscillator circuit between the terminals from which the converted energy is taken out and sent to the output load 3. 25 A control transformer for an energy converter by disconnecting the current from a DC source to at least one switch (4) with a control pole (4b), the converted energy being passed through an inductance connected to a load (3) (2'a) is delivered to a load (3), characterized in that it comprises: - a primary winding (6'a) connected in series between the switching device (4) and the inductance (2'a); - a secondary winding (6'b) magnetically coupled to said primary winding, which secondary winding (6'b) is connected to said control electrode (4b) and provides periodicity to said switching means (4) The conduction control signal, the inductor (2'b) and the primary line (6'a) of the control transformer are wound on a magnetically coupled magnetic circuit, and the inductor (2' in the magnetic circuit a) and the magnetic field (2'c, 6) generated by said primary winding (6'a) are substantially perpendicular to each other.

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