LLC topology magnetic integration high-frequency transformer and resonance circuit

Abstract

The invention discloses an LLC topology magnetic integration high-frequency transformer which comprises a transformer framework, a primary winding, a secondary winding, two main magnetic cores and a leakage magnetic core. A primary winding groove and a secondary winding groove are formed in the transformer framework, a primary winding is arranged on the primary winding groove, a secondary winding is arranged on the secondary winding groove, a hollow cavity is formed in the transformer framework in a penetrating mode, a second cavity is formed in one side of the transformer framework, and the second cavity is perpendicular to the hollow cavity. The second cavity is communicated with the hollow cavity; the two main magnetic cores comprise the first main magnetic core and the second main magnetic core, magnetic arms of the first main magnetic core and the second main magnetic core are arranged in the hollow cavity, magnetic arms of the leakage magnetic core are arranged in the second cavity, and the leakage magnetic core divides magnetic circuits of the first main magnetic core and the second main magnetic core. The transformer is simple in structure, the leakage inductance of the transformer does not need to be adjusted through a complex process, production is convenient, and high voltage conversion efficiency of the transformer can be guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and in particular to an LLC topology magnetic integrated high-frequency transformer and a resonant circuit. Background Art

[0002] The LLC topology circuit is a resonant circuit that achieves a constant output voltage by controlling the switching frequency. It is generally composed of components such as an isolation transformer and a resonant inductor. The isolation transformer and the resonant inductor are independent of each other. As two discrete components, this makes the power supply structure complex, the volume increases, and the cost is high. This is not conducive to the current small-volume drive power application.

[0003] Another solution is to integrate the resonant inductor into the magnetic integrated transformer in the transformer, and form a resonant circuit by treating the leakage inductance of the transformer as the resonant inductor together with the resonant capacitor and load in the circuit; such as the Chinese invention patent with authorization announcement number CN106373751B, a high-frequency transformer, which forms a bypass magnetic circuit in the high-frequency transformer by setting a leakage magnetic core, thereby increasing the leakage inductance, reducing the production process and wiring complexity, and improving the efficiency and stability of the resonant power supply.

[0004] With the miniaturization of electronic equipment, the transformers used in their power supplies are also getting smaller and smaller. Due to space limitations, the transformers need to be further miniaturized, simplified, and low-cost. For example, in a LED drive circuit of more than ten W, a transformer with a smaller size and simpler installation steps is required. After being made into a small size, the above-mentioned transformer works in a high-frequency environment where the leakage core is located in the main magnetic field line loop. During operation, the magnetic loss is large, the power conversion efficiency is low, and it cannot be well applied. Summary of the invention

[0005] The purpose of the present invention is to provide an LLC topology magnetic integrated high-frequency transformer and a resonant circuit. By setting a leakage magnetic core on the side to block the primary-secondary coupling magnetic circuit, the transformer leakage inductance is increased to eliminate the external resonant inductor, thereby eliminating the external resonant inductor of the LLC topology architecture, simplifying the transformer structure and the process, and ensuring high-efficiency voltage conversion of the transformer.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: an LLC topology magnetic integrated high-frequency transformer, comprising a transformer skeleton, a primary winding and a secondary winding, two main magnetic cores and a leakage magnetic core; the transformer skeleton is provided with a primary winding groove and a secondary winding groove, the primary winding groove is provided with a primary winding, the secondary winding groove is provided with a secondary winding, a hollow cavity is penetrated through the transformer skeleton, a second cavity is opened on one side of the transformer skeleton, the second cavity is perpendicularly arranged to the hollow cavity, and the second cavity is connected to the hollow cavity; the two main magnetic cores include a first main magnetic core and a second main magnetic core, the magnetic arms of the first main magnetic core and the second main magnetic core are respectively arranged in the hollow cavity, the magnetic arms of the leakage magnetic core are arranged in the second cavity, and the leakage magnetic core divides the magnetic circuits of the first main magnetic core and the second main magnetic core.

[0007] The present invention is further configured as follows: the primary winding groove and the secondary winding groove are arranged in parallel, a base is provided on the transformer skeleton, a primary pin portion and a secondary pin portion are provided on the base, and the base is arranged in parallel with the primary winding groove and the secondary winding groove.

[0008] The present invention is further configured as follows: the first main magnetic core is a first U-shaped magnetic core, the second main magnetic core is a second U-shaped magnetic core, the leakage magnetic core is an E-shaped magnetic core, the two ends of the first U-shaped magnetic core and the second U-shaped magnetic core are abutted against each other to form a magnetic circuit, and the E-shaped magnetic core is arranged on the side of the magnetic circuit.

[0009] The present invention is further configured as follows: the magnetic arms at both ends of the E-shaped magnetic core respectively abut the first U-shaped magnetic core and the second U-shaped magnetic core, and the middle column of the E-shaped magnetic core is separated from the first U-shaped magnetic core and the second U-shaped magnetic core to form a gap, and the gap value is D1.

[0010] The present invention is further configured as follows: the magnetic arms of the first U-shaped magnetic core and the magnetic arms of the second U-shaped magnetic core are respectively located in the hollow cavity, and the cross-sectional area of ​​the magnetic arms located in the hollow cavity is larger than the magnetic arms located outside the hollow cavity, and the middle column of the E-shaped magnetic core is arranged in the second cavity.

[0011] The present invention is further configured as follows: the first main magnetic core is a first E-type magnetic core, the second main magnetic core is a second E-type magnetic core, the leakage magnetic core is an I-type magnetic core, the three ends of the first E-type magnetic core and the second E-type magnetic core are abutted to form a magnetic circuit, and the I-type magnetic core is arranged in the first E-type magnetic core or the second E-type magnetic core.

[0012] The present invention is further configured as follows: the main magnetic arms of the first E-type magnetic core and the second E-type magnetic core are arranged in the hollow cavity, the cross-sectional area of ​​the main magnetic arms of the first E-type magnetic core and the second E-type magnetic core is larger than the magnetic arms on both sides, and the I-type magnetic core is arranged in the second cavity.

[0013] A further setting of the present invention is that the I-shaped core is separated from the first E-shaped core and the second E-shaped core to define a gap, and the gap value is D1.

[0014] A further setting of the present invention is that the gap value D1 satisfies: 0.5mm < D1 < 1.2mm, the turn ratio of the primary winding to the secondary winding is 72:18, and the operating frequency range of the LLC topology magnetically integrated high-frequency transformer is 60 - 120 kHz.

[0015] A resonant circuit includes a resonant capacitor C and any one of the above LLC topology magnetically integrated high-frequency transformers. The resonant capacitor C is connected to the primary end of the LLC topology magnetically integrated high-frequency transformer, and the secondary end of the LLC topology magnetically integrated high-frequency transformer is connected to a bridge synchronous rectifier.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The UUE-type core structure or the EEI-type core structure blocks the primary-secondary coupled magnetic path through the E-shaped middle column or the I-shaped core, increases the leakage inductance of the transformer, and eliminates the external resonant inductor. The external resonant inductor of the LLC topology structure is eliminated, which not only simplifies the transformer structure but also simplifies the process, ensuring high-efficiency voltage conversion of the transformer; at the same time, during the manufacturing process, the leakage inductance value can be adjusted by adjusting the side leakage core to control the LLC operating frequency; in this way, the original simple winding method is ensured, there is no need for complex process to adjust the transformer leakage inductance, the production is convenient, and the high-efficiency voltage conversion of the transformer can be ensured. Description of the Drawings

[0017] Figure 1 is a three-dimensional view of the LLC topology magnetically integrated high-frequency transformer in Embodiment 1.

[0018] Figure 2 is a structure diagram of the UUE-type core in Embodiment 1.

[0019] Figure 3 is a front view of the LLC topology magnetically integrated high-frequency transformer in Embodiment 1.

[0020] Figure 4 is Figure 3 a sectional view taken along the A-A plane of

[0021] Figure 5 is a structure diagram of the transformer skeleton in Embodiment 1.

[0022] Figure 6 is another structure diagram of the transformer skeleton in Embodiment 1.

[0023] Figure 7 is a structure diagram of the EEI-type core in Embodiment 2.

[0024] Figure 8 is a resonant circuit diagram in Embodiment 3.

[0025] In the figure: 100, transformer skeleton; 101, primary winding groove; 102, secondary winding groove; 103, hollow cavity; 104, second cavity; 105, base; 106, primary pin portion; 107, secondary pin portion; 201, primary winding; 202, secondary winding; 301, first U-shaped magnetic core; 302, second U-shaped magnetic core; 303, E-shaped magnetic core; 304, middle column; 401, first E-shaped magnetic core; 402, second E-shaped magnetic core; 403, I-shaped magnetic core. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0027] Example 1

[0028] like Figure 1-6 As shown, an embodiment of the present invention provides an LLC topology magnetic integrated high-frequency transformer, the LLC topology magnetic integrated high-frequency transformer includes a transformer skeleton 100, a primary winding 201 and a secondary winding 202, and also includes two main magnetic cores, namely a first main magnetic core and a second main magnetic core, a leakage magnetic core, and a primary winding slot 101 and a secondary winding slot 102 are arranged on the transformer skeleton 100, and the primary winding slot 101 and the secondary winding slot 102 are arranged around the transformer skeleton 100, and the primary winding slot 101 and the secondary winding slot 102 are arranged around the transformer skeleton 100. The winding grooves 102 are parallel to each other, the coils wound on the primary winding grooves 101 constitute the primary winding 201, and the coils wound on the secondary winding grooves 102 constitute the secondary winding 202; a hollow cavity 103 is provided through the transformer skeleton 100, and the hollow cavity 103 is perpendicular to the primary winding grooves 101 and the secondary winding grooves 102 on the same cross section; a second cavity 104 is opened on one side of the transformer skeleton 100, the second cavity 104 is perpendicular to the hollow cavity 103, and the second cavity 104 is connected to the hollow cavity 103.

[0029] The magnetic arms of the two main magnetic cores are inserted into the hollow cavity 103 of the transformer skeleton 100 , and the leakage magnetic core is inserted into the second cavity 104 .

[0030] like Figure 2As shown, in this embodiment, the main magnetic core is a UU-type combined magnetic core including a first U-type magnetic core 301 and a second U-type magnetic core 302. The two ends of the first U-type magnetic core 301 and the second U-type magnetic core 302 correspond to each other to form a magnetic circuit. The leakage magnetic core is an E-type magnetic core 303. The E-type magnetic core 303 is arranged on the side of the magnetic circuit. The E-type magnetic core 303 divides the magnetic circuit into a first bypass and a second bypass. The magnetic core combination is a UUE-type combination. At the same time, the middle column 304 of the E-type magnetic core 303 is separated from the first U-type magnetic core 301 and the second U-type magnetic core 302 to define a gap. The magnetic flux lines form leakage inductance through the bypass and the air, and the gap value of this interval is set to D1.

[0031] like Figure 3 , Figure 4 As shown, the magnetic arms of the first U-shaped magnetic core 301 and the second U-shaped magnetic core 302 are respectively inserted into the transformer skeleton 100 at both ends of the hollow cavity 103, and the two ends of the first U-shaped magnetic core 301 and the second U-shaped magnetic core 302 are butted to form a magnetic circuit, and the middle column 304 of the E-shaped magnetic core 303 is inserted into the second cavity 104, and the magnetic arms at both ends of the E-shaped magnetic core 303 are respectively butted against the first U-shaped magnetic core 301 and the second U-shaped magnetic core 302.

[0032] Preferably, the cross-sectional area of ​​the magnetic arm inserted into the hollow cavity 103 of the two main magnetic cores is larger than the cross-sectional area of ​​the magnetic arm on the other side, so that more magnetic lines of force can be converged in the magnetic core.

[0033] The magnetic circuit formed by butting the two ends of the two main magnets together can be of various geometric shapes. In this embodiment, preferably, the cross-sections of the two main magnets are rectangular, which reduces production costs and simplifies assembly.

[0034] like Figure 6 As shown, in actual operation, the magnetic core vibrates during operation, the top of the transformer skeleton 100 is conical and has a magnetic core limiting groove, and the bottom of the transformer skeleton 100 also has a magnetic core limiting groove; a plurality of through holes are provided on the transformer skeleton 100 to reduce the weight of the transformer and further reduce the weight.

[0035] The magnetically integrated high-frequency transformer is a transformer in which the primary coil is wound on the primary winding slot 101 of the inverter frame, and the secondary coil is wound on the secondary winding slot 102 of the frame. Energy is transferred through a UU-shaped magnetic core in the middle. The side E-shaped magnetic core 303 is used to block the magnetic field between the primary winding 201 and the secondary winding 202, thereby increasing the transformer leakage inductance and eliminating the need for an external resonant inductor.

[0036] In this embodiment, a base 105 is provided on the transformer skeleton 100, and a primary pin portion 106 and a secondary pin portion 107 are provided on the base 105. The primary pin portion 106 is provided with a primary pin, and the secondary pin portion 107 is provided with a secondary pin. The primary pin is connected to the primary winding 201, and the secondary pin is connected to the secondary winding 202. The primary winding groove 101 and the secondary winding groove 102 are arranged parallel to the base 105.

[0037] The transformer stores energy in the UU-shaped magnetic core through high-frequency switching of the primary coil, and then couples it to the secondary coil through the magnetic core. In actual production, the input voltage ratio can be changed by changing the turns ratio of the primary coil and the secondary coil, thereby increasing or decreasing the voltage and outputting it through the secondary coil.

[0038] The magnetic integrated high-frequency transformer blocks the primary-secondary coupling by changing the core structure, and changes the conventional square core composed of two parts, such as EE and EF, to a UUE type (UU composed of upper and lower parts and E type placed on the side) composed of three parts; the primary-secondary coupling magnetic circuit is blocked by the E-type middle column 304, and the transformer leakage inductance is increased to save the external resonant inductor. The external resonant inductor of the LLC topology architecture is saved, which simplifies the transformer structure and process, and ensures the high-efficiency voltage conversion of the transformer.

[0039] At the same time, during the manufacturing process, the leakage inductance value can be adjusted to control the LLC operating frequency by adjusting the height of the middle column 304 of the side E-shaped magnetic core 303; this ensures the original simple winding method, does not require complex processes to adjust the transformer leakage inductance, is convenient for production, and can also ensure high efficiency of transformer voltage conversion.

[0040] Example 2

[0041] like Figure 7 As shown, in this embodiment, the main magnetic core is an EE-type composite magnetic core, including a first E-type magnetic core 401 and a second E-type magnetic core 402. The three ends of the first E-type magnetic core 401 and the second E-type magnetic core 402 are abutted to form a magnetic circuit. The leakage magnetic core is an I-type magnetic core 403. The I-type magnetic core 403 is arranged in the first E-type magnetic core 401 or the second E-type magnetic core 402 to block the magnetic lines of force between the first E-type magnetic core 401 and the second E-type magnetic core 402, thereby increasing or decreasing the leakage inductance of the transformer.

[0042] The cross-sectional area of ​​the main magnetic arms of the first E-type magnetic core 401 and the second E-type magnetic core 402 is larger than that of the two magnetic arms. The main magnetic arms of the first E-type magnetic core 401 and the second E-type magnetic core 402 are respectively inserted into the transformer skeleton 100 at both ends of the hollow cavity 103. The ends of the first E-type magnetic core 401 and the second E-type magnetic core 402 are butt-jointed to form a magnetic circuit. The I-type magnetic core 403 is inserted into the second cavity 104. The I-type magnetic core 403 is separated from the first E-type magnetic core 401 and the second E-type magnetic core 402 to define a gap, and the gap value is D1.

[0043] In this embodiment, the I-shaped core 403 can be arranged such that one end abuts against the first E-shaped core 401 and the other end is separated from the second E-shaped core 402 by a gap; alternatively, both ends of the I-shaped core 403 can be separated from the first E-shaped core 401 and the second E-shaped core 402 by gaps.

[0044] Embodiment 3

[0045] The magnitude of the gap value D1 affects the leakage inductance value of the transformer, thereby affecting the function of the transformer in an actual circuit. The gap value D1 can be preset in actual production for the power value in an actual resonant circuit. In this embodiment, the preferred values of this transformer structure in a resonant circuit are disclosed. The turn ratio of the primary winding and the secondary winding of the transformer is 72:18. In the operating frequency range of 60 - 120 kHz, the D1 value: 0.5 mm < D1 < 1.2 mm, and it is optimal in the power range of 5W - 45W.

[0046] Embodiment 4

[0047] As Figure 8 shown, the embodiment of the present invention further provides a resonant circuit, including a resonant capacitor Cr and any one of the above LLC topology magnetic integrated high-frequency transformers. The resonant capacitor Cr is connected to the primary end of the LLC topology magnetic integrated high-frequency transformer. The primary end of the LLC topology magnetic integrated high-frequency transformer is connected with several MOS transistors, and the secondary end of the LLC topology magnetic integrated high-frequency transformer is connected to a bridge synchronous rectifier.

[0048] The above is only the preferred embodiment of the present invention. Therefore, any equivalent changes or modifications made according to the structures, features, and principles described in the scope of this invention patent application are included in the scope of this invention patent application.

Claims

1. An LLC topology magnetic integrated high frequency transformer, characterized in that: The invention comprises a transformer skeleton (100), a primary winding (201) and a secondary winding (202), two main magnetic cores and a leakage magnetic core; the transformer skeleton (100) is provided with a primary winding slot (101) and a secondary winding slot (102); the primary winding slot (101) is provided with a primary winding (201); the secondary winding slot (102) is provided with a secondary winding (202); a hollow cavity (103) is provided through the transformer skeleton (100); A second cavity (104) is provided on one side of the frame (100), the second cavity (104) is arranged perpendicularly to the hollow cavity (103), and the second cavity (104) is communicated with the hollow cavity (103); the two main magnetic cores include a first main magnetic core and a second main magnetic core, the magnetic arms of the first main magnetic core and the second main magnetic core are respectively arranged in the hollow cavity (103), the magnetic arms of the leakage magnetic core are arranged in the second cavity (104), and the leakage magnetic core divides the magnetic circuits of the first main magnetic core and the second main magnetic core.

2. The LLC topology magnetic integrated high frequency transformer according to claim 1, characterized in that: The primary winding groove (101) and the secondary winding groove (102) are arranged in parallel, the transformer skeleton (100) is provided with a base (105), the base (105) is provided with a primary pin portion (106) and a secondary pin portion (107), and the base (105) is arranged in parallel with the primary winding groove (101) and the secondary winding groove (102).

3. The LLC topology magnetic integrated high frequency transformer according to claim 1, characterized in that: The first main magnetic core is a first U-shaped magnetic core (301), the second main magnetic core is a second U-shaped magnetic core (302), the leakage magnetic core is an E-shaped magnetic core (303), two ends of the first U-shaped magnetic core (301) and the second U-shaped magnetic core (302) are abutted against each other to form a magnetic circuit, and the E-shaped magnetic core (303) is arranged on the side of the magnetic circuit.

4. The LLC topology magnetic integrated high frequency transformer according to claim 3, characterized in that: The magnetic arms at both ends of the E-shaped magnetic core (303) respectively abut against the first U-shaped magnetic core (301) and the second U-shaped magnetic core (302), and the middle column (304) of the E-shaped magnetic core (303) is separated from the first U-shaped magnetic core (301) and the second U-shaped magnetic core (302) to form a gap, and the gap value is D1.

5. The LLC topology magnetic integrated high frequency transformer according to claim 4, characterized in that: The magnetic arms of the first U-shaped magnetic core (301) and the magnetic arms of the second U-shaped magnetic core (302) are respectively located in the hollow cavity (103), and the cross-sectional area of ​​the magnetic arms located in the hollow cavity (103) is larger than that of the magnetic arms located outside the hollow cavity (103), and the middle column (304) of the E-shaped magnetic core (303) is arranged in the second cavity (104).

6. The LLC topology magnetic integrated high frequency transformer according to claim 1, characterized in that: The first main magnetic core is a first E-type magnetic core (401), the second main magnetic core is a second E-type magnetic core (402), the leakage magnetic core is an I-type magnetic core (403), three ends of the first E-type magnetic core (401) and the second E-type magnetic core (402) are abutted to form a magnetic circuit, and the I-type magnetic core (403) is arranged in the first E-type magnetic core (401) or the second E-type magnetic core (402).

7. The LLC topology magnetic integrated high frequency transformer according to claim 6, characterized in that: The main magnetic arms of the first E-shaped magnetic core (401) and the second E-shaped magnetic core (402) are arranged in the hollow cavity (103). The cross-sectional area of the main magnetic arms of the first E-shaped magnetic core (401) and the second E-shaped magnetic core (402) is larger than that of the two side magnetic arms. The I-shaped magnetic core (403) is arranged in the second cavity (104).

8. The LLC topology magnetic integrated high frequency transformer according to claim 7, characterized in that: The I-shaped magnetic core (403) is separated from the first E-shaped magnetic core (401) and the second E-shaped magnetic core (402) to define a gap with a gap value of D1.

9. The LLC topology magnetic integrated high frequency transformer according to claims 4 and 8, characterized in that: The gap value D1 satisfies: 0.5mm < D1 < 1.2mm. The turn ratio of the primary winding (201) and the secondary winding (202) is 72:

18. The operating frequency range of the LLC topology magnetically integrated high-frequency transformer is 60 - 120 kHz.

10. A resonant circuit, characterized in that: It includes a resonant capacitor Cr and any one of the LLC topology magnetically integrated high-frequency transformers as claimed in claims 1 - 8. The resonant capacitor Cr is connected to the primary end of the LLC topology magnetically integrated high-frequency transformer. The primary end of the LLC topology magnetically integrated high-frequency transformer is connected with a plurality of MOS transistors. The secondary end of the LLC topology magnetically integrated high-frequency transformer is connected to a bridge synchronous rectifier.

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