CN110266193B

CN110266193B - Structure suitable for high-power boost LLC resonant converter

Info

Publication number: CN110266193B
Application number: CN201910577600.7A
Authority: CN
Inventors: 谢奕婷; 王乃增; 周昂扬; 杨旭
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2019-06-28
Filing date: 2019-06-28
Publication date: 2020-05-22
Anticipated expiration: 2039-06-28
Also published as: CN110266193A

Abstract

The invention discloses a structure suitable for a high-power boost LLC resonant converter, which comprises an inversion side, a rectification side, a transformer and a radiator, wherein the inversion side and the rectification side are connected with the transformer and are arranged above the radiator; a driving plate is inserted into the top of the inversion side, and a minimum system plate is inserted into the driving plate; two half-bridge modules, two resonant inductors and an inverter side PCB are respectively arranged on the inverter side, and a positive bus copper sheet, a negative bus copper sheet and a pair of resonant capacitor groups are respectively arranged above the inverter side PCB; the two resonant inductors are connected to the inverting side wiring terminal of the transformer through litz wires; the rectifying side comprises four diode modules, a rectifying side PCB is connected above the four diode modules, a filter capacitor group formed by connecting five capacitors in parallel is arranged on the rectifying side PCB, and the four diode modules and the filter capacitor group are connected with a transformer through the rectifying side PCB. On the premise of ensuring heat dissipation and electromagnetic compatibility, higher power density is realized.

Description

Structure suitable for high-power boost LLC resonant converter

Technical Field

The invention belongs to the field of structural design of power electronic converters, and particularly relates to a structure suitable for a high-power boost LLC resonant converter.

Background

The rapid development of power electronics technology places higher demands on the power density and efficiency of the converter. The LLC resonant converter can realize zero-voltage switching-on of a primary side switching tube and zero-current switching-off of a secondary side rectifying tube, and the excellent soft switching characteristic can greatly reduce the switching loss and improve the efficiency; the high-frequency design of the switch can be realized, so that the power density is improved; meanwhile, the LLC resonant converter has the advantages of wide input voltage range and small switching stress, and the LLC resonant converter becomes a topology commonly used at present.

A high power boost LLC converter is a practical application class of LLC converters. In the structural design process of this type of converter, the following problems mainly exist: firstly, generally, high power means that the sizes of active devices (switching tubes and diodes) and passive devices (inductors, capacitors and transformers) of the converter are increased correspondingly, and the arrangement of the devices is difficult, so that the power density of the converter is influenced; secondly, the resonant current of the high-power boost LLC converter is large, and heat dissipation of heating elements in the converter, such as a switching device, a resonant inductor and a transformer, is more difficult; thirdly, the high-power main circuit containing the high-speed action switching tube is easy to cause electromagnetic interference to the control loop, influence the stability of control and simultaneously cause electromagnetic pollution to the outside.

Therefore, in order to realize a high-power boost LLC resonant converter with high power density, a reasonable structural design is needed in many aspects such as comprehensive device model selection, heat dissipation, electromagnetic compatibility, and the like.

Disclosure of Invention

In order to solve the above-mentioned defects in the prior art, an object of the present invention is to provide a high-power boost LLC resonant converter structure, which can achieve a higher power density on the premise of ensuring heat dissipation and electromagnetic compatibility.

The invention is realized by the following technical scheme.

A structure suitable for a high-power boost LLC resonant converter comprises an inversion side, a rectification side, a transformer and a radiator, wherein the inversion side and the rectification side are connected with the transformer and are arranged above the radiator; a driving plate is inserted into the top of the inversion side, and a minimum system plate is inserted into the driving plate;

the inverter side is provided with two half-bridge modules and two resonant inductors respectively, and further comprises an inverter side PCB on the two half-bridge modules and the two resonant inductors, wherein a positive bus copper sheet, a negative bus copper sheet and a pair of resonant capacitor groups, which are connected with the positive electrodes and the negative electrodes of the two half-bridge modules, are arranged above the inverter side PCB respectively; a pair of input filter capacitor sets is connected between the positive bus copper sheet and the negative bus copper sheet, and litz wires are arranged below the PCB on the inversion side; the two resonant inductors are connected to a first inversion side wiring terminal of the transformer through litz wires;

the rectifying side comprises four diode modules, a rectifying side PCB is connected above the four diode modules, a filter capacitor group formed by connecting five capacitors in parallel is arranged on the rectifying side PCB, and the four diode modules and the filter capacitor group are connected with a transformer through the rectifying side PCB.

With respect to the above technical solutions, the present invention has a further preferable solution:

further, two half-bridge modules are distributed on the left side of the inversion side in parallel, two resonance inductors are distributed on the right side of the inversion side in the front and back direction, and the two half-bridge modules and the two resonance inductors are fastened on the radiator through screws.

Furthermore, the positive pole of the first half-bridge module and the positive pole of the second half-bridge module on the two half-bridge modules are connected through a positive bus copper sheet, and the negative pole of the first half-bridge module and the negative pole of the second half-bridge module are connected through a negative bus copper sheet.

Furthermore, the first half-bridge module is connected with the resonance capacitor bank on the PCB at the inversion side through the middle point of the first half-bridge module and then connected to the second inversion side wiring end of the transformer.

Furthermore, the second half-bridge module is connected with a connecting terminal of a litz wire through the midpoint of the second half-bridge module, is connected with two series resonance inductors through the litz wire and is then connected to a first inversion side connecting terminal of the transformer.

Furthermore, the litz wire is attached to the PCB on the inversion side.

Further, the driving board is arranged right above the half-bridge module and connected to the half-bridge module through a contact pin.

Further, the minimum system board is connected to the driving board through pins and is staggered with a space formed vertically upward by the half-bridge module.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

1) the invention adopts a reasonable device model selection method and a compact layout mode to integrate the high-power boost LLC resonant converter in a cuboid structure, thereby realizing high power density and being beneficial to modular combination;

2) the primary half-bridge module, the secondary rectifier diode module, the transformer and the inductor in the converter are tightly attached to a radiator, so that the radiating requirement of the converter under the heavy-current working condition is met;

3) by reducing the areas of the driving loop and the main power loop to the maximum extent, staggering the vertical space of the DSP minimum system board and the half-bridge module and the like, the electromagnetic interference of the main power loop of the circuit to the control loop is reduced, the parasitic parameters in the loop are reduced, the good operation of the control loop is ensured, and the electromagnetic sensitivity of the two loops is reduced.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention:

fig. 1 is a high power boost LLC resonant converter topology in accordance with the present invention;

FIG. 2 is a top plan view of the overall structure of the present invention;

FIG. 3(a) is a front view of the inversion side;

FIG. 3(b) is a cross-sectional view A-A of the inversion side;

FIG. 4(a) is a front view of the rectifying side;

fig. 4(b) is a plan view of the rectifying side.

In the figure: 101. an inverter side, 102, a rectifier side, 103, a transformer, 104, a heat sink, 105, a drive board, 106, a minimum system board, 1, a first half-bridge module, 2, a second half-bridge module, 3, a gasket, 4, a negative bus copper sheet, 5, a screw, 6, a pin, 7, a first resonant capacitor bank, 8, a second resonant capacitor bank, 9, a first resonant inductor, 10, a second resonant inductor, 11, an inverter side PCB board, 12, a first inverter side terminal, 13, a second inverter side terminal, 14, a positive bus copper sheet, 15, a first input filter capacitor bank, 16, a second input filter capacitor bank, 17, a positive electrode of the first half-bridge module, 18, a negative electrode of the first half-bridge module, 19, a midpoint of the first half-bridge module, 20, a positive electrode of the second half-bridge module, 21, a negative electrode of the second half-bridge module, 22, a midpoint of the second half-bridge module, 23. litz wire, 24 litz wire connection terminals, 25, first diode module, 26, second diode module, 27, third diode module, 28, fourth diode module, 29, filter capacitor bank, 30, rectifying side PCB board, 31, first rectifying side connection terminals, 32, second rectifying side connection terminals, 33, first output connection terminals, 34, second output connection terminals.

Detailed Description

The present invention will now be described in detail with reference to the drawings and specific embodiments, wherein the exemplary embodiments and descriptions of the present invention are provided to explain the present invention without limiting the invention thereto.

Fig. 1 is a high power boost LLC resonant converter topology to which the present invention relates. And the inversion side and the rectification side of the LLC resonant converter are connected through a transformer. The inverter side is provided with an input filter capacitor C_iSwitching tubes S1-S4 and resonant inductor L_rResonant capacitor C_rThe rectification side comprises rectifier diodes D1-D4 and an output filter capacitor C_oAnd (4) forming. The switching tubes S1-S4 actually adopt two half-

bridge modules

1 and 2, and the rectifier diodes D1-D4 actually adopt four diode modules 25-28.

Fig. 2 shows a top view of the whole structure of the present invention, in which three main parts of the LLC resonant converter can be seen: an inverter side 101, a rectifier side 102 and a transformer 103. Considering the application of high power, the inversion side 101 and the rectification side 102 are designed into two separate parts which are arranged in parallel in the width direction, a transformer 103 is arranged on one side of the inversion side 101 and one side of the rectification side 102, the inversion side 101 and the rectification side 102 are connected with the transformer 103, and the sum of the widths of the inversion side 101 and the rectification side 102 corresponds to the length of the transformer 103. The overall layout of the inverter side 101, the rectifier side 102 and the transformer 103 is rectangular in plan view, and the heights of the three are the same. The inverter side 101 and the rectifier side 102 are connected to the transformer 103 and integrally disposed above the heat sink 104, as shown in fig. 3(a), and the length and width are determined according to the overall length and width of the inverter side 101, the rectifier side 102, and the transformer 103. The whole resonant converter is a cuboid module. A drive board 105 is inserted on the top of the inverter side 101, and a minimum system board 106 is provided on the top of the inverter side 101 and the rectifier side 102. A minimal system board 106 is inserted on the drive board 105.

As shown in fig. 3(a) and 3(b), a front view and a sectional view a-a of the inverter side 101 are shown. Two half-bridge modules, first, second half-

bridge module

1, 2 distribute in contravariant side 101 left side by side promptly, two resonance inductances, first,

second resonance inductance

9, 10 distribute in contravariant side 101 right side around promptly, first, second half-

bridge module

1, 2 and first,

second resonance inductance

9, 10 pass through the screw fastening on radiator 104, guarantee its heat dissipation. The top parts of the first half-bridge module 1 and the second half-bridge module 2 and the first resonant inductor 9 and the second resonant inductor 10 are provided with an inversion side PCB board 11, a negative bus copper sheet 4 and a positive bus copper sheet 14 are respectively arranged above the inversion side PCB board 11, and the negative bus copper sheet 4 and the positive bus copper sheet 14 are connected with the positive electrode and the negative electrode of the first half-bridge module 1 and the second half-bridge module 2. A pair of resonance capacitor groups, namely a first resonance capacitor group 7 and a second resonance capacitor group 8, are arranged above the inversion side PCB 11, and the first resonance capacitor group 7 and the second resonance capacitor group 8 are symmetrically distributed along the middle part of the inversion side PCB 11; litz wires 23 are provided under the inverter-side PCB 11.

As shown in fig. 3(b), the positive electrode 17 of the first half-bridge module and the positive electrode 20 of the second half-bridge module on the two half-

bridge modules

1 and 2 are connected through the positive bus copper sheet 14, the negative electrode 18 of the first half-bridge module and the negative electrode 21 of the second half-bridge module are connected through the negative bus copper sheet 4, and the first input filter capacitor bank 15 and the second input filter capacitor bank 16 are welded between the positive bus copper sheet 14 and the negative bus copper sheet 4 for reducing the switching high-frequency oscillation of the half-bridge modules. The positive electrode 17 of the first half-bridge module and the negative electrode 18 of the first half-bridge module are padded with gaskets for being staggered with the PCB 11 on the inversion side in the vertical direction, the negative bus copper sheet 4 and the positive bus copper sheet 14 are connected with the first half-bridge module 1 and the second half-bridge module 2 through screws 5, and the driving plate 105 is connected with the first half-bridge module 1 and the second half-bridge module 2 through a contact pin 6.

The first half-bridge module 1 is connected to the first and second

resonant capacitor banks

7 and 8 on the inverter-side PCB 11 through the midpoint 19 of the first half-bridge module, and then connected to the second inverter-side terminal 13 of the transformer 103. The second half-bridge module 2 is connected with a litz wire connecting terminal 24 through a midpoint 22 of the second half-bridge module, connected with two first and

second resonance inductors

9 and 10 connected in series through a litz wire 23, and then connected to an inverting side terminal 12 of the first transformer. The litz wire 23 is attached to the inverter side PCB 11 to reduce the power loop area and improve the electromagnetic compatibility.

The spacer 3 is used for vertically shifting the

copper sheets

14 and 4 of the positive and negative bus bars and the reverse side PCB 11. The driving board 105 is disposed right above the first and second half-

bridge modules

1 and 2, and connected to the first and second half-

bridge modules

1 and 2 through the pin 6 to provide driving signals thereto, so as to reduce the area of the driving circuit, reduce parasitic parameters of the driving circuit, avoid gate oscillation, and reduce electromagnetic sensitivity.

The minimum system board 106 is connected to the driver board via pin 6, and is offset from the space formed vertically above the first and second half-

bridge modules

1 and 2 to reduce electromagnetic interference of the main power loop with the minimum system board 106.

As shown in fig. 4(a) and 4(b), the rectification side 102 is a front view and a plan view. The four diode modules, i.e., the first, second, third, and

fourth diode modules

25, 26, 27, and 28 are screwed to the heat sink 104 and screwed to the rectification side PCB board 30. The filter capacitor bank 29 with five capacitors connected in parallel is arranged on the left side of the four diode modules, the height of the filter capacitor bank needs to be noted in the capacitor model selection stage, and the position of a minimum system board 106 is reserved in the layout process. The first and second rectifying-

side connection terminals

31 and 32 are connected to the rectifying-side PCB board 30 by screws. The ac power output from the transformer 103 to the first and second rectifying-

side terminals

31 and 32 is rectified by the four

diode modules

25, 26, 27 and 28, filtered by the output filter capacitor bank 29, converted into dc power, and finally connected to the load through the first and

second output terminals

33 and 34.

The invention divides the whole structure into four parts: the structure is different from that of most LLC converters, wherein the inversion side, the rectification side and the transformer are designed on the same PCB. In the invention, the inverter side and the rectifier side are designed into two discrete parts which are arranged in parallel in the width direction in consideration of the application occasion of high power. The sum of the widths of the inversion side and the rectification side is close to the length of the transformer, the top view of the overall layout is rectangular, and the heights of the inversion side and the rectification side are close to each other. The radiator is placed at the bottom, and the length and the width are determined according to the integral layout of the first three. The whole resonant converter is a cuboid module.

Furthermore, the inversion side is composed of two half-bridge modules and a driving board thereof, a DSP minimum system board, an input filter capacitor, a resonance inductor and a resonance capacitor. The half-bridge module and the resonant inductor need to be tightly attached to a radiator for heat dissipation, and therefore are arranged below the PCB on the inversion side. The positive end and the negative end of two half-bridge modules are connected through the copper sheet, and the input filter capacitor welds between two copper sheets for reduce the switch high frequency oscillation of half-bridge module. The driving board of the half-bridge module is connected with the two half-bridge modules through pins and arranged right above the half-bridge modules, so that the area of a driving loop is reduced, parasitic parameters of the driving loop are reduced, grid oscillation is avoided, and electromagnetic sensitivity is reduced. The DSP minimum system board is externally connected above the driving board through a contact pin, but is staggered with a space formed vertically upwards by the half-bridge module, and electromagnetic interference of the main power loop on the DSP minimum system board is reduced. The high-power boost LLC resonant converter has large resonant current, so that the capacitor size meeting the current requirement is large, and the capacitor cannot be well integrated in a circuit, therefore, small capacitors with proper height are selected to be connected in parallel, the total volume of the capacitors is reduced, and the capacitors are arranged above a PCB. The height of the resonant inductor magnetic core is selected to be not higher than the distance between the PCB and the radiator, and under the principle, if the maximum inductance value cannot reach the designed resonant inductance value, the mode of connecting a plurality of inductors in series is changed. The resonant inductor is connected with a litz wire and is tightly attached to the PCB, so that the area of the main power loop is minimum.

Furthermore, the rectifying side is composed of four diode modules and an output filter capacitor. The diode module needs to be tightly attached to the radiator for heat dissipation and arranged below the PCB. The output filter capacitor consists of highly suitable capacitors connected in parallel, and care is taken to leave the minimum system board position.

By adopting the structural arrangement mode, the invention can realize higher power density on the premise of ensuring heat dissipation and electromagnetic compatibility.

The present invention is not limited to the above-mentioned embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.

Claims

1. The structure is suitable for a high-power boost LLC resonant converter and is characterized by comprising an inversion side (101), a rectification side (102), a transformer (103) and a radiator (104), wherein the inversion side (101) and the rectification side (102) are connected with the transformer (103), and the inversion side (101), the rectification side (102) and the transformer (103) are arranged above the radiator (104) together; a driving plate (105) is inserted into the top of the inversion side (101), and a minimum system plate (106) is inserted into the driving plate (105);

the inverter side (101) is respectively provided with two half-bridge modules (1, 2) and two resonant inductors (9, 10), and further comprises an inverter side PCB (11) on the two half-bridge modules (1, 2) and the two resonant inductors (9, 10), a positive bus copper sheet (14) and a negative bus copper sheet (4) which are respectively connected with the positive and negative electrodes of the two half-bridge modules (1, 2) are arranged above the inverter side PCB (11), and a pair of resonant capacitor groups (7, 8) is also arranged above the inverter side PCB (11); a pair of input filter capacitor sets (15, 16) is connected between the positive bus copper sheet (14) and the negative bus copper sheet (4), and litz wires (23) are arranged below the inversion side PCB (11); the two resonant inductors (9, 10) are connected to a first inverter side terminal (12) of the transformer through a litz wire (23);

the rectifying side (102) comprises four diode modules (25), (26), (27) and (28), a rectifying side PCB (30) is connected above the four diode modules, a filter capacitor group (29) which is distributed with the four diode modules in a staggered mode and is formed by connecting five capacitors in parallel is arranged on the rectifying side PCB (30), and the four diode modules and the filter capacitor group (29) are connected with a transformer (103) through the rectifying side PCB (30).

2. The structure of claim 1, wherein the two half-bridge modules (1, 2) are arranged in parallel on the left side of the inverter side (101), the two resonant inductors (9, 10) are arranged in front and behind on the right side of the inverter side (101), and the two half-bridge modules (1, 2) and the two resonant inductors (9, 10) are fastened to the heat sink (104) by screws.

3. The structure suitable for the high-power boost LLC resonant converter according to claim 1, characterized in that the positive pole (17) of the first half-bridge module and the positive pole (20) of the second half-bridge module on the two half-bridge modules (1, 2) are connected by a positive bus copper sheet (14), and the negative pole (18) of the first half-bridge module and the negative pole (21) of the second half-bridge module are connected by a negative bus copper sheet (4).

4. A structure suitable for high power boost LLC resonant converter as claimed in claim 3, characterized in that the first half-bridge module (1) is connected via its midpoint (19) to the resonant capacitor bank (7, 8) on the inverter side PCB (11) and then to the second inverter side terminal (13) of the transformer (103).

5. A structure suitable for high power boost LLC resonant converter as claimed in claim 3, characterized in that the second half-bridge module (2) is connected via its midpoint (22) to the connection terminal (24) of the litz wire (23), via the litz wire (23) to the two series-connected resonant inductors (9, 10) and then to the first inverter-side connection (12) of the transformer.

6. The structure of claim 1, wherein the litz wire (23) is attached to an inverter-side PCB (11).

7. A structure suitable for high power boost LLC resonant converter as claimed in claim 1, characterized in that the driver board (105) is placed directly above the two half-bridge modules (1, 2) and connected to the two half-bridge modules (1, 2) via pins (6).

8. A structure suitable for high power boost LLC resonant converter as claimed in claim 1, characterized in that the minimum system board (106) is connected to the driving board (105) via pins (6) offset from the space formed vertically upwards by the two half-bridge modules (1, 2).