CN220156406U

CN220156406U - Three-phase LLC resonant circuit and resonant converter

Info

Publication number: CN220156406U
Application number: CN202321706609.1U
Authority: CN
Inventors: 石伟; 刘中伟; 肖正虎; 史耀华
Original assignee: Xi'an Topology Electric Power Technology Co ltd
Current assignee: Xi'an Topology Electric Power Technology Co ltd
Priority date: 2023-06-30
Filing date: 2023-06-30
Publication date: 2023-12-08
Anticipated expiration: 2033-06-30

Abstract

The utility model relates to a three-phase LLC resonant circuit and a resonant converter. The three-phase LLC resonant circuit comprises a first resonant inductor, a second resonant inductor, a third resonant inductor, a first transformer, a second transformer and a third transformer; the first end of the first resonant inductor is connected with the first end of the primary winding of the first transformer; the first end of the second resonant inductor is connected with the first end of the primary winding of the second transformer; the first end of the third resonant inductor is connected with the first end of the primary winding of the third transformer; the second end of the first resonant inductor is connected between the second resonant inductor and the primary winding of the second transformer; the second end of the second resonant inductor is connected between the third resonant inductor and the primary winding of the third transformer; the second end of the third resonant inductor is connected between the first resonant inductor and the primary winding of the first transformer, and the three-phase LLC resonant circuit can be applied to high-power occasions.

Description

Three-phase LLC resonant circuit and resonant converter

Technical Field

The utility model relates to the technical field of converters, in particular to a three-phase LLC resonant circuit and a resonant converter.

Background

The fundamental principle of the LLC resonant circuit is to utilize the resonance characteristic of the LC series resonant circuit to reduce the switching loss of the switching device. The three-phase LLC resonant circuit is equivalent to three half-bridge LLC circuits which are coupled together and operated in a staggered way, so that ripple waves can be reduced, and the problem of uneven current caused by inconsistent resonance parameters can be restrained.

However, when the three-phase LLC resonant circuit in the conventional technology is applied to a high-power occasion, a smaller inductance resonant inductor is required, but the small inductance resonant inductor is not easy to produce, so that the production difficulty of the three-phase LLC resonant circuit suitable for the high-power occasion is high.

Disclosure of Invention

Based on this, it is necessary to provide a three-phase LLC resonant circuit and a resonant converter that can reduce the difficulty in producing a three-phase LLC resonant circuit suitable for high-power applications.

In a first aspect, the present utility model provides a three-phase LLC resonant circuit comprising: the first resonant inductor, the second resonant inductor, the third resonant inductor, the first transformer, the second transformer and the third transformer; the first end of the first resonant inductor is connected with the first end of the primary winding of the first transformer; the first end of the second resonant inductor is connected with the first end of the primary winding of the second transformer; the first end of the third resonant inductor is connected with the first end of the primary winding of the third transformer; the second end of the first resonant inductor is connected between the second resonant inductor and the primary winding of the second transformer; the second end of the second resonant inductor is connected between the third resonant inductor and the primary winding of the third transformer; the second end of the third resonant inductor is connected between the first resonant inductor and the primary winding of the first transformer; the second end of the primary winding of the first transformer, the second end of the primary winding of the second transformer and the second end of the primary winding of the third transformer are all connected with a first bridge circuit; the secondary winding of the first transformer, the secondary winding of the second transformer and the secondary winding of the third transformer are all connected with the second bridge circuit.

In one embodiment, the resonant circuit further comprises: a first capacitor, a second capacitor, and a third capacitor; the first capacitor, the second capacitor and the third capacitor are respectively arranged on the primary winding of the first transformer, the primary winding of the second transformer and the primary winding of the third transformer.

In one embodiment, the first capacitor is connected between the second end of the primary winding of the first transformer and the first bridge circuit; the second capacitor is connected between the second end of the primary winding of the second transformer and the first bridge circuit; the third capacitor is connected between the second end of the primary winding of the third transformer and the first bridge circuit.

In one embodiment, a first end of the first capacitor is connected with a first end of the primary winding of the first transformer and a second end of the third resonant inductor, and a second end of the first capacitor is connected with the first end of the first resonant inductor; the first end of the second capacitor is connected with the first end of the primary winding of the second transformer and the second end of the first resonant inductor, and the second end of the second capacitor is connected with the first end of the second resonant inductor; the first end of the third capacitor is connected with the first end of the primary winding of the third transformer and the second end of the second resonant inductor, and the second end of the third capacitor is connected with the first end of the third resonant inductor.

In one embodiment, the resonant circuit further comprises: a fourth resonant inductor, a fifth resonant inductor and a sixth resonant inductor; the first end of the fourth resonant inductor is connected with the first end of the secondary winding of the first transformer; the first end of the fifth resonant inductor is connected with the first end of the secondary winding of the second transformer; the first end of the sixth resonant inductor is connected with the first end of the secondary winding of the third transformer; the second end of the fourth resonant inductor is connected between the fifth resonant inductor and the secondary winding of the second transformer; the second end of the fifth resonant inductor is connected between the sixth resonant inductor and the secondary winding of the third transformer; the second end of the sixth resonant inductor is connected between the fourth resonant inductor and the secondary winding of the first transformer; the second end of the secondary winding of the first transformer, the second end of the secondary winding of the second transformer and the second end of the secondary winding of the third transformer are all connected with a second bridge circuit.

In one embodiment, the resonant circuit further comprises: a fourth capacitance, a fifth capacitance, and a sixth capacitance; the fourth capacitor, the fifth capacitor and the sixth capacitor are respectively arranged on the secondary winding of the first transformer, the secondary winding of the second transformer and the secondary winding of the third transformer.

In one embodiment, a fourth capacitor is connected between the second end of the secondary winding of the first transformer and the second bridge circuit; the fifth capacitor is connected between the second end of the secondary winding of the second transformer and the second bridge circuit; the sixth capacitor is connected between the second end of the secondary winding of the third transformer and the second bridge circuit.

In one embodiment, a first end of the fourth capacitor is connected to both the first end of the secondary winding of the first transformer and the second end of the sixth resonant inductor, and a second end of the fourth capacitor is connected to the first end of the fourth resonant inductor; the first end of the fifth capacitor is connected with the first end of the secondary winding of the second transformer and the second end of the fourth resonant inductor, and the second end of the fifth capacitor is connected with the first end of the fifth resonant inductor; the first end of the sixth capacitor is connected with the first end of the secondary winding of the third transformer and the second end of the fifth resonant inductor, and the second end of the sixth capacitor is connected with the first end of the sixth resonant inductor.

In one embodiment, a first end of a secondary winding of a first transformer is connected to a second end of a secondary winding of a second transformer, the first end of the secondary winding of the second transformer is connected to a second end of a secondary winding of a third transformer, and the first end of the secondary winding of the third transformer is connected to the second end of the secondary winding of the first transformer; the second end of the secondary winding of the first transformer, the second end of the secondary winding of the second transformer and the second end of the secondary winding of the third transformer are all connected with a second bridge circuit.

In one embodiment, the first end of the secondary winding of the first transformer, the first end of the secondary winding of the second transformer, and the first end of the secondary winding of the third transformer are interconnected; the second end of the secondary winding of the first transformer, the second end of the secondary winding of the second transformer and the second end of the secondary winding of the third transformer are all connected with a second bridge circuit.

In a second aspect, the present utility model provides a three-phase LLC resonant converter comprising a first bridge circuit, a second bridge circuit and a resonant circuit as described in any of the first aspects above, the first and second bridge circuits each being connected to the resonant circuit.

The three-phase LLC resonant circuit comprises a first resonant inductor, a second resonant inductor, a third resonant inductor, a first transformer, a second transformer and a third transformer; the first end of the first resonant inductor is connected with the first end of the primary winding of the first transformer; the first end of the second resonant inductor is connected with the first end of the primary winding of the second transformer; the first end of the third resonant inductor is connected with the first end of the primary winding of the third transformer; the second end of the first resonant inductor is connected between the second resonant inductor and the primary winding of the second transformer; the second end of the second resonant inductor is connected between the third resonant inductor and the primary winding of the third transformer; the second end of the third resonant inductor is connected between the first resonant inductor and the primary winding of the first transformer; the second end of the primary winding of the first transformer, the second end of the primary winding of the second transformer and the second end of the primary winding of the third transformer are all connected with a first bridge circuit; the secondary winding of the first transformer, the secondary winding of the second transformer and the secondary winding of the third transformer are connected with the second bridge circuit, so that the first resonant inductor, the second resonant inductor and the third resonant inductor are connected in a triangular structure, and when the three-phase LLC resonant circuit in the utility model achieves the same effect as the three-phase LLC resonant circuit in the equivalent traditional technology, the inductance of each resonant inductor is required to be improved, and compared with the three-phase LLC resonant circuit in the traditional technology, the resonant inductance in the three-phase LLC resonant circuit does not need to be smaller, and the production difficulty of the three-phase LLC resonant circuit suitable for high-power occasions is further reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments or the conventional techniques of the present utility model, the drawings required for the descriptions of the embodiments or the conventional techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1 is a schematic diagram of a conventional three-phase LLC resonant converter in accordance with one embodiment;

FIG. 2 is a schematic diagram of a three-phase LLC resonant circuit according to one embodiment;

FIG. 3 is a circuit diagram of a connection between a capacitor and a primary winding of a transformer in one embodiment;

FIG. 4 is a circuit diagram of another connection between a capacitor and a primary winding of a transformer in one embodiment;

FIG. 5 is another three-phase LLC resonant circuit in one embodiment;

FIG. 6 is a circuit diagram of a connection between a capacitor and a secondary winding of a transformer in one embodiment;

FIG. 7 is a circuit diagram of another connection of a capacitor to a secondary winding of a transformer in one embodiment;

FIG. 8 is a circuit diagram of a connection between secondary windings of a transformer in one embodiment;

fig. 9 is a three-phase LLC resonant converter in one embodiment.

Detailed Description

In order that the utility model may be readily understood, a more complete description of the utility model will be rendered by reference to the appended drawings. Embodiments of the utility model are illustrated in the accompanying drawings. This utility model may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used herein in the description of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model.

It will be understood that the terms first, second, etc. as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the utility model. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

It is to be understood that in the following embodiments, "connected" is understood to mean "electrically connected", "communicatively connected", etc., if the connected circuits, modules, units, etc., have electrical or data transfer between them.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Also, the term "and/or" as used in this specification includes any and all combinations of the associated listed items.

It is known by those skilled in the art that, when the power is larger, the design inductance of the resonant inductor is generally smaller, and the design capacity of the resonant capacitor is larger, because when the power is larger, the current flowing through the resonant cavity is larger, the voltage drop generated at two ends of the capacitor is also larger, and the resonant capacitor is generally limited by the rated voltage and cannot be limited and large, therefore, the capacity of the resonant capacitor must be increased, so that the voltage of the resonant capacitor is reduced, and the resonant capacitor is prevented from exceeding the rated voltage specification. The resonance frequency of the three-phase LLC resonant circuit is determined by the resonance inductance and the resonance capacitance, and the resonance frequency is lower as the inductance of the resonance inductance is larger under the condition that the resonance capacitance is unchanged, and the resonance frequency is lower as the resonance capacitance is larger under the condition that the resonance inductance is unchanged. Therefore, in a high-power design, in order to keep the resonant frequency in a suitable range, it is generally necessary to increase the resonant capacitance to meet the voltage specification of the capacitance, and therefore, the inductance of the resonant inductance must be reduced.

However, the resonant inductor is generally a high-frequency working element, the magnetic core is generally a high-permeability power ferrite, a larger air gap is needed to be formed on the magnetic core in order to reduce the inductance of the resonant inductor, eddy current loss is usually generated in a copper winding by the large air gap of the magnetic core, the sectional air gap is adopted as much as possible, and the length of each air gap is reduced, so that the manufacturing difficulty of the resonant inductor is increased. In addition, the inductance is too small, two side effects are caused, namely, the resonance inductance parameter is not easy to control during production and processing, the inductance deviation slightly occurs, a larger percentage error is caused, and the leakage inductance or other parasitic parameters of other elements in the circuit such as a transformer play an obvious role due to the fact that the inductance of the resonance inductance is too small, and therefore the working state of the circuit is changed.

Therefore, the three-phase LLC resonant circuit is suitable for being applied to high-power occasions, and is unfavorable to design and production due to the small-inductance-required resonant inductance.

As shown in fig. 1, a three-phase LLC resonant converter in the conventional technology is provided, in which three resonant inductors are connected in a star-shaped structure, and if the resonant converter is applied to a high-power occasion, there is a problem that it is difficult to produce because a resonant inductor with small inductance is required.

Based on this, it is necessary to propose a three-phase LLC resonant circuit that does not require a small inductance of the resonant inductance.

In one embodiment, as shown in FIG. 2, a three-phase LLC resonant circuit is provided, the resonant circuit comprising: the first, second and third resonant inductors L1, L2, L3, T1, T2 and T3.

The first end of the first resonant inductor L1 is connected with the first end of the primary winding of the first transformer T1; the first end of the second resonant inductor L2 is connected with the first end of the primary winding of the second transformer T2; the first end of the third resonant inductor L3 is connected to the first end of the primary winding of the third transformer T3.

The second end of the first resonant inductor L1 is connected between the second resonant inductor L2 and the primary winding of the second transformer T2; the second end of the second resonant inductor L2 is connected between the third resonant inductor L3 and the primary winding of the third transformer T3; the second end of the third resonant inductor L3 is connected between the first resonant inductor L1 and the primary winding of the first transformer T1.

The second end of the primary winding of the first transformer T1, the second end of the primary winding of the second transformer T2 and the second end of the primary winding of the third transformer T3 are all connected with the first bridge circuit 101; the secondary winding of the first transformer T1, the secondary winding of the second transformer T2 and the secondary winding of the third transformer T3 are all connected to the second bridge circuit 102.

The secondary windings of the first transformer T1, the secondary windings of the second transformer T2 and the secondary windings of the third transformer T3 are all connected to the second bridge circuit 102 in a specific manner as described in detail below.

Through the connection mode, the embodiment realizes that the resonant inductance in the circuit in the traditional technology is converted from the equivalent star connection method to the triangle connection method, and in order to achieve the same effect as the equivalent star connection method circuit, the inductance of each resonant inductance in the embodiment needs to be improved by 3 times according to the conversion principle of the star connection method and the triangle connection method.

In addition, the effective value of the current on each resonant inductor of the triangular connection method is reduced by 1.732 times compared with that of the star connection method under the same effect, so that the wire diameter required by each resonant inductor is obviously reduced under the same current density, and in order to improve the inductance of each resonant inductor, the inductance can be improved by increasing the winding turns of the resonant inductor, so that the resonant inductor of the equivalent star connection method is changed into the resonant inductor of the triangular connection method, and the winding turns of the resonant inductor are actually increased, and then the air gap of the magnetic core can be reduced by increasing the winding turns of the resonant inductor under the condition that the magnetic core of the resonant inductor in the triangular connection method is the same as the magnetic core of the resonant inductor in the star connection method, so that the problem that in the prior art, in order to produce the resonant inductor with lower inductance, the magnetic core needs to be provided with a larger air gap, and the difficulty of producing the resonant inductor is avoided.

In summary, the three-phase LLC resonant circuit includes a first resonant inductor L1, a second resonant inductor L2, a third resonant inductor L3, a first transformer T1, a second transformer T2, and a third transformer T3; the first end of the first resonant inductor L1 is connected with the first end of the primary winding of the first transformer T1; the first end of the second resonant inductor L2 is connected with the first end of the primary winding of the second transformer T2; the first end of the third resonant inductor L3 is connected with the first end of the primary winding of the third transformer T3; the second end of the first resonant inductor L1 is connected between the second resonant inductor L2 and the primary winding of the second transformer T2; the second end of the second resonant inductor L2 is connected between the third resonant inductor L3 and the primary winding of the third transformer T3; the second end of the third resonant inductor L3 is connected between the first resonant inductor L1 and the primary winding of the first transformer T1; the second end of the primary winding of the first transformer T1, the second end of the primary winding of the second transformer T2 and the second end of the primary winding of the third transformer T3 are all connected with the first bridge circuit 101; the secondary winding of the first transformer T1, the secondary winding of the second transformer T2 and the secondary winding of the third transformer T3 are all connected with the second bridge circuit 102, so that the first resonant inductor, the second resonant inductor and the third resonant inductor are connected in a triangular structure, and when the three-phase LLC resonant circuit in the utility model achieves the same effect as the three-phase LLC resonant circuit in the equivalent conventional technology, the inductance of each resonant inductor needs to be improved, and compared with the three-phase LLC resonant circuit in the conventional technology, the resonant inductance in the three-phase LLC resonant circuit does not need to be smaller, thereby reducing the production difficulty of the three-phase LLC resonant circuit suitable for high-power occasions.

In one embodiment, the resonant circuit further comprises: a first capacitor C1, a second capacitor C2, and a third capacitor C3; the first capacitor C1, the second capacitor C2 and the third capacitor C3 are respectively disposed on the primary winding of the first transformer T1, the primary winding of the second transformer T2 and the primary winding of the third transformer T3.

Optionally, as shown in fig. 3, a circuit diagram of a connection relationship between a capacitor and a primary winding of a transformer is provided, and a first capacitor C1 is connected between a second end of the primary winding of a first transformer T1 and a first bridge circuit 101; the second capacitor C2 is connected between the second end of the primary winding of the second transformer T2 and the first bridge circuit 101; the third capacitor C3 is connected between the second end of the primary winding of the third transformer T3 and the first bridge circuit 101.

Optionally, as shown in fig. 4, a circuit diagram of another connection relationship between a capacitor and a primary winding of a transformer is provided, where a first end of a first capacitor C1 is connected to both a first end of the primary winding of the first transformer T1 and a second end of a third resonant inductor L3, and a second end of the first capacitor C1 is connected to a first end of the first resonant inductor L1; the first end of the second capacitor C2 is connected with the first end of the primary winding of the second transformer T2 and the second end of the first resonant inductor L1, and the second end of the second capacitor C2 is connected with the first end of the second resonant inductor L2; the first end of the third capacitor C3 is connected with the first end of the primary winding of the third transformer T3 and the second end of the second resonant inductor L2, and the second end of the third capacitor C3 is connected with the first end of the third resonant inductor L3.

In this embodiment, the first capacitor C1, the second capacitor C2 and the third capacitor C3 are all resonant capacitors. The first capacitor C1, the second capacitor C2 and the third capacitor C3 in fig. 3 are connected in a star-shaped structure, and the first capacitor C1, the second capacitor C2 and the third capacitor C3 in fig. 4 are connected in a triangle-shaped structure.

In one embodiment, as depicted in FIG. 5, another three-phase LLC resonant circuit is provided, the resonant circuit further comprising: fourth resonant inductance L4, fifth resonant inductance L5, and sixth resonant inductance L6.

The first end of the fourth resonant inductor L4 is connected with the first end of the secondary winding of the first transformer T1; a first end of the fifth resonant inductor L5 is connected with a first end of a secondary winding of the second transformer T2; a first end of the sixth resonant inductor L6 is connected to a first end of the secondary winding of the third transformer T3.

The second end of the fourth resonant inductor L4 is connected between the fifth resonant inductor L5 and the secondary winding of the second transformer T2; the second end of the fifth resonant inductor L5 is connected between the sixth resonant inductor L6 and the secondary winding of the third transformer T3; the second end of the sixth resonant inductor L6 is connected between the fourth resonant inductor L4 and the secondary winding of the first transformer T1; the second end of the secondary winding of the first transformer T1, the second end of the secondary winding of the second transformer T2 and the second end of the secondary winding of the third transformer T2 are all connected with a second bridge circuit.

In this embodiment, the fourth resonant inductor L4, the fifth resonant inductor L5 and the sixth resonant inductor L6 are connected in a triangle structure, so that the inductance of the resonant inductor can be improved, and the production difficulty of the three-phase LLC resonant circuit suitable for high-power applications is reduced. In addition, the embodiment realizes that the two sides of the transformer are symmetrical, and a symmetrical three-phase LLC resonant circuit is formed.

In one embodiment, the resonant circuit further comprises: a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6; the fourth capacitor C4, the fifth capacitor C5 and the sixth capacitor C6 are respectively disposed on the secondary winding of the first transformer T1, the secondary winding of the second transformer T2 and the secondary winding of the third transformer T3.

Optionally, as shown in fig. 6, a circuit diagram of a connection relationship between a capacitor and a secondary winding of a transformer is provided, and a fourth capacitor C1 is connected between a second end of the secondary winding of the first transformer T1 and the second bridge circuit 102; the fifth capacitor C5 is connected between the second end of the secondary winding of the second transformer T2 and the second bridge circuit 102; the sixth capacitor C6 is connected between the second end of the secondary winding of the third transformer T3 and the second bridge circuit 102.

Optionally, as shown in fig. 7, a circuit diagram of another connection relationship between a capacitor and a secondary winding of a transformer is provided, where a first end of a fourth capacitor C4 is connected to both a first end of the secondary winding of the first transformer T1 and a second end of a sixth resonant inductor L6, and a second end of the fourth capacitor C4 is connected to a first end of the fourth resonant inductor L4; the first end of the fifth capacitor C5 is connected with the first end of the secondary winding of the second transformer T2 and the second end of the fourth resonant inductor L4, and the second end of the fifth capacitor C5 is connected with the first end of the fifth resonant inductor L5; the first end of the sixth capacitor C6 is connected to the first end of the secondary winding of the third transformer T3 and the second end of the fifth resonant inductor L5, and the second end of the sixth capacitor C6 is connected to the first end of the sixth resonant inductor L6.

In this embodiment, the fourth capacitor C4, the fifth capacitor C5 and the sixth capacitor C6 are all resonant capacitors. The fourth capacitor C4, the fifth capacitor C5 and the sixth capacitor C6 in fig. 6 are connected in a star-shaped structure, and the fourth capacitor C4, the fifth capacitor C5 and the sixth capacitor C6 in fig. 7 are connected in a triangle-shaped structure.

The secondary windings of the first transformer T1, the secondary windings of the second transformer T2, the secondary windings of the third transformer T3 and the second bridge circuit 102 are connected as follows:

optionally, as shown in fig. 2, a first end of the secondary winding of the first transformer T1 is connected to a second end of the secondary winding of the second transformer T2, a first end of the secondary winding of the second transformer T2 is connected to a second end of the secondary winding of the third transformer T3, and a first end of the secondary winding of the third transformer T3 is connected to a second end of the secondary winding of the first transformer T1; the second end of the secondary winding of the first transformer T1, the second end of the secondary winding of the second transformer T2 and the second end of the secondary winding of the third transformer T3 are connected to the second bridge circuit 102.

Alternatively, as shown in fig. 8, a circuit diagram of a connection relationship between secondary windings of a transformer is provided, the first end of the secondary winding of the first transformer T1, the first end of the secondary winding of the second transformer T2, and the first end of the secondary winding of the third transformer T3 being interconnected; the second end of the secondary winding of the first transformer T1, the second end of the secondary winding of the second transformer T2 and the second end of the secondary winding of the third transformer T3 are connected to the second bridge circuit 102.

In this embodiment, the secondary winding of the first transformer T1, the secondary winding of the second transformer T2 and the secondary winding of the third transformer T3 in fig. 2 are connected in a triangle structure, and the secondary winding of the first transformer T1, the secondary winding of the second transformer T2 and the secondary winding of the third transformer T3 in fig. 8 are connected in a star structure.

In the above embodiment, the primary winding of the first transformer T1, the primary winding of the second transformer T2, and the primary winding of the third transformer T3 are each provided with an excitation inductance.

In one embodiment, as shown in fig. 9, a three-phase LLC resonant converter is provided, which includes a first bridge circuit 101, a second bridge circuit 102, and a resonant circuit as described in any of the resonant circuit embodiments above, with both the first bridge circuit 101 and the second bridge circuit 102 being connected to the resonant circuit.

Optionally, the first bridge circuit 101 includes a first bridge arm, a second bridge arm, a third bridge arm and a seventh capacitor C7, where the first bridge arm, the second bridge arm and the third bridge arm include a plurality of switching tubes connected in series with each other, and the first bridge arm, the second bridge arm and the third bridge arm are all connected in parallel with the seventh capacitor C7. Wherein, the switching tube can be a MOS tube.

For example, the first bridge arm includes a first switching tube Q1 and a second switching tube Q2; the second bridge arm comprises a third switching tube Q3 and a fourth switching tube Q4; the third bridge arm comprises a fifth switching tube Q5 and a sixth switching tube Q6; the second end of the primary winding of the first transformer T1, the second end of the primary winding of the second transformer T2, and the second end of the primary winding of the third transformer T3 in any one of the resonant circuits are respectively connected between the first switching tube Q1 and the second switching tube Q2, between the third switching tube Q3 and the fourth switching tube Q4, and between the fifth switching tube Q5 and the sixth switching tube Q6.

Optionally, the second bridge circuit 102 includes a fourth bridge arm, a fifth bridge arm, a sixth bridge arm, and an eighth capacitor C8, where the fourth bridge arm, the fifth bridge arm, and the sixth bridge arm each include a plurality of switching tubes connected in series with each other, and the fourth bridge arm, the fifth bridge arm, and the sixth bridge arm are all connected in parallel with the eighth capacitor C8. Wherein, the switching tube can be a MOS tube.

For example, the fourth bridge arm includes a seventh switching tube Q7 and an eighth switching tube Q8; the fifth bridge arm comprises a ninth switching tube Q9 and a tenth switching tube Q10; the sixth bridge arm comprises an eleventh switching tube Q11 and a twelfth switching tube Q12; in the resonant circuit, the second end of the secondary winding of the first transformer T1, the second end of the secondary winding of the second transformer T2, and the second end of the secondary winding of the third transformer T3 are connected between the seventh switching tube Q7 and the eighth switching tube Q8, between the ninth switching tube Q9 and the tenth switching tube Q10, and between the eleventh switching tube Q11 and the twelfth switching tube Q12, respectively.

The primary winding of the first transformer T1, the primary winding of the second transformer T2 and the primary winding of the third transformer T3 are respectively provided with a first excitation inductance M1, a second excitation inductance M2 and a third excitation inductance M3.

In the description of the present specification, reference to the term "some embodiments," "other embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples merely represent a few embodiments of the present utility model, which are described in more detail and are not to be construed as limiting the scope of the present utility model. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model. Accordingly, the scope of the utility model should be assessed as that of the appended claims.

Claims

1. A three-phase LLC resonant circuit, said resonant circuit comprising: the first resonant inductor, the second resonant inductor, the third resonant inductor, the first transformer, the second transformer and the third transformer;

the first end of the first resonant inductor is connected with the first end of the primary winding of the first transformer;

the first end of the second resonant inductor is connected with the first end of the primary winding of the second transformer;

the first end of the third resonant inductor is connected with the first end of the primary winding of the third transformer;

the second end of the first resonant inductor is connected between the second resonant inductor and the primary winding of the second transformer;

the second end of the second resonant inductor is connected between the third resonant inductor and the primary winding of the third transformer;

the second end of the third resonant inductor is connected between the first resonant inductor and the primary winding of the first transformer;

the second end of the primary winding of the first transformer, the second end of the primary winding of the second transformer and the second end of the primary winding of the third transformer are all connected with a first bridge circuit;

the secondary winding of the first transformer, the secondary winding of the second transformer and the secondary winding of the third transformer are all connected with a second bridge circuit.

2. The resonant circuit of claim 1, wherein the resonant circuit further comprises: a first capacitor, a second capacitor, and a third capacitor; the first capacitor, the second capacitor and the third capacitor are respectively arranged on the primary winding of the first transformer, the primary winding of the second transformer and the primary winding of the third transformer.

3. The resonant circuit of claim 2, wherein the first capacitor is connected between the second end of the primary winding of the first transformer and the first bridge circuit;

the second capacitor is connected between the second end of the primary winding of the second transformer and the first bridge circuit;

the third capacitor is connected between the second end of the primary winding of the third transformer and the first bridge circuit.

4. The resonant circuit of claim 2, wherein a first end of the first capacitor is connected to both a first end of the primary winding of the first transformer and a second end of the third resonant inductor, and wherein a second end of the first capacitor is connected to the first end of the first resonant inductor;

the first end of the second capacitor is connected with the first end of the primary winding of the second transformer and the second end of the first resonant inductor, and the second end of the second capacitor is connected with the first end of the second resonant inductor;

the first end of the third capacitor is connected with the first end of the primary winding of the third transformer and the second end of the second resonant inductor, and the second end of the third capacitor is connected with the first end of the third resonant inductor.

5. The resonant circuit of claim 1, wherein the resonant circuit further comprises: a fourth resonant inductor, a fifth resonant inductor and a sixth resonant inductor;

the first end of the fourth resonant inductor is connected with the first end of the secondary winding of the first transformer;

the first end of the fifth resonant inductor is connected with the first end of the secondary winding of the second transformer;

the first end of the sixth resonant inductor is connected with the first end of the secondary winding of the third transformer;

the second end of the fourth resonant inductor is connected between the fifth resonant inductor and the secondary winding of the second transformer;

the second end of the fifth resonant inductor is connected between the sixth resonant inductor and the secondary winding of the third transformer;

the second end of the sixth resonant inductor is connected between the fourth resonant inductor and the secondary winding of the first transformer;

the second end of the secondary winding of the first transformer, the second end of the secondary winding of the second transformer and the second end of the secondary winding of the third transformer are all connected with the second bridge circuit.

6. The resonant circuit of claim 5, further comprising: a fourth capacitance, a fifth capacitance, and a sixth capacitance; the fourth capacitor, the fifth capacitor and the sixth capacitor are respectively arranged on the secondary winding of the first transformer, the secondary winding of the second transformer and the secondary winding of the third transformer.

7. The resonant circuit of claim 6, wherein the fourth capacitor is connected between the second end of the secondary winding of the first transformer and the second bridge circuit;

the fifth capacitor is connected between the second end of the secondary winding of the second transformer and the second bridge circuit;

the sixth capacitor is connected between the second end of the secondary winding of the third transformer and the second bridge circuit.

8. The resonant circuit of claim 6, wherein a first end of the fourth capacitor is connected to both the first end of the secondary winding of the first transformer and the second end of the sixth resonant inductor, and a second end of the fourth capacitor is connected to the first end of the fourth resonant inductor;

the first end of the fifth capacitor is connected with the first end of the secondary winding of the second transformer and the second end of the fourth resonant inductor, and the second end of the fifth capacitor is connected with the first end of the fifth resonant inductor;

the first end of the sixth capacitor is connected with the first end of the secondary winding of the third transformer and the second end of the fifth resonant inductor, and the second end of the sixth capacitor is connected with the first end of the sixth resonant inductor.

9. The resonant circuit of claim 1, wherein a first end of the secondary winding of the first transformer is connected to a second end of the secondary winding of the second transformer, wherein a first end of the secondary winding of the second transformer is connected to a second end of the secondary winding of the third transformer, and wherein a first end of the secondary winding of the third transformer is connected to a second end of the secondary winding of the first transformer;

10. The resonant circuit of claim 1, wherein the first end of the secondary winding of the first transformer, the first end of the secondary winding of the second transformer, and the first end of the secondary winding of the third transformer are interconnected;

11. A three-phase LLC resonant converter comprising a first bridge circuit, a second bridge circuit, and a resonant circuit as claimed in any one of claims 1 to 10, both the first bridge circuit and the second bridge circuit being connected to the resonant circuit.