Multiphase LLC resonant converter

Abstract

A multiphase LLC resonant converter comprises a resonant cavity, a switching circuit and a rectifying circuit. The resonant cavity comprises a resonant circuit and a transformer. The resonant circuit comprises a plurality of resonant inductors, and the resonant inductors are connected in a delta connection mode. The switching circuit is disposed on the primary side of the transformer and has a half-bridge structure. The rectifier circuit is disposed on the secondary side of the transformer and has a full-bridge structure. The multiphase LLC resonant converter provided by the utility model can reduce magnetic core loss and has good current balance capability.

Description

TECHNICAL FIELD

[0001] The present utility model relates to a kind of resonant converters, and more specifically, to a kind of multi-phase LLC resonant converters. BACKGROUND

[0002] The common multi-phase LLC resonant converter architecture nowadays is half-bridge half-bridge architecture and full-bridge full-bridge architecture. In low-voltage large-current applications, the half-bridge half-bridge architecture has a large proportion of coil loss on the primary side and the secondary side of the transformer, and the full-bridge full-bridge architecture has a large proportion of core loss of the transformer. Therefore, how to find a balance point between coil loss and core loss is an important issue in the technical field. In addition, the current multi-phase LLC resonant converter architecture may not be able to reduce core loss, and when there is an error in the passive components, it is also unable to balance the current. SUMMARY

[0003] The present utility model relates to a kind of multi-phase LLC resonant converters, which can reduce core loss and have good current balancing capability.

[0004] The multi-phase LLC resonant converter of the utility model embodiment includes a resonant cavity, a switching circuit, and a rectifier circuit. The resonant cavity includes a resonant circuit and a transformer. The resonant circuit includes a plurality of resonant inductors, and the resonant inductors are connected in a delta configuration. The switching circuit is configured on the primary side of the transformer and has a half-bridge structure. The rectifier circuit is configured on the secondary side of the transformer and has a full-bridge structure.

[0005] In the embodiment of the utility model, the resonant circuit further includes a plurality of resonant capacitors, and the plurality of resonant inductors and the plurality of resonant capacitors are connected in a delta configuration.

[0006] In the embodiment of the utility model, the switching circuit includes a plurality of switching components, and the gate-source voltage signals of the plurality of switching components are complementary to each other.

[0007] In the embodiment of the utility model, there is a dead time between the complementary gate-source voltage signals.

[0008] In the embodiment of the utility model, the size of the dead time depends on the parasitic capacitance values of the switching components on the primary side and the secondary side and the magnetizing inductance value of the transformer.

[0009] In the embodiment of the utility model, the gate source voltage signal includes first voltage signal, second voltage signal, third voltage signal, fourth voltage signal, fifth voltage signal and sixth voltage signal, wherein the phase difference of first voltage signal and fourth voltage signal is 180 degrees, the phase difference of second voltage signal and fifth voltage signal is 180 degrees, and the phase difference of third voltage signal and sixth voltage signal is 180 degrees.

[0010] In the embodiment of the utility model, the phase difference between first voltage signal, second voltage signal and third voltage signal is 120 degrees, and the phase difference between fourth voltage signal, fifth voltage signal and sixth voltage signal is 120 degrees.

[0011] In the embodiment of the utility model, the multiple switch assemblies are connected in star connection.

[0012] In the embodiment of the utility model, the rectifier circuit includes multiple switch assembly groups, and each switch assembly group is coupled between first voltage and second voltage and controlled by multiple control signals.

[0013] In the embodiment of the utility model, when the drain source voltage signal of the switch assembly in the switch assembly group is less than the reference voltage, the multiple control signals control the switch assembly in the switch assembly group to be turned on.

[0014] In the embodiment of the utility model, the magnetic core of the resonant inductor and the magnetic core of the transformer are integrated to form an integrated magnetic core structure, and the integrated magnetic core structure includes a first cover plate, a second cover plate and an intermediate layer plate, and wherein the first core column, the second core column and the third core column of the resonant inductor are located between the first cover plate and the intermediate layer plate, and the first core column, the second core column and the third core column of the transformer are located between the intermediate layer plate and the second cover plate.

[0015] In the embodiment of the utility model, each core column of the first core column, the second core column and the third core column of the resonant inductor has an air gap.

[0016] In the embodiment of the utility model, the air gap of the second core column is smaller than the air gap of the first core column and the air gap of the third core column.

[0017] In the embodiment of the utility model, the air gap of the first core column is equal to the air gap of the third core column.

[0018] In the embodiment of the utility model, the air gap exists in the middle of each core column.

[0019] In the embodiment of the utility model, the first core column, the second core column and the third core column of the resonant inductance are not coupled with each other.

[0020] In the embodiment of the utility model, the coils on the first core column, the second core column and the third core column of the resonant inductance are wound in the same direction.

[0021] In the embodiment of the utility model, there is an air gap in each of the first core column, the second core column and the third core column of the transformer.

[0022] In the embodiment of the utility model, the air gap of the second core column is smaller than the air gap of the first core column and the air gap of the third core column.

[0023] In the embodiment of the utility model, the air gap of the first core column is equal to the air gap of the third core column.

[0024] In the embodiment of the utility model, the air gap exists in the middle of each of the core columns.

[0025] In the embodiment of the utility model, the first core column, the second core column and the third core column of the transformer are not coupled with each other.

[0026] In the embodiment of the utility model, the primary side coil and the secondary side coil on the first core column, the second core column and the third core column of the transformer are wound in the same direction.

[0027] In the embodiment of the utility model, the primary side coil and the secondary side coil on the first core column, the second core column and the third core column of the transformer are symmetrically wound based on the reference axis.

[0028] In the embodiment of the utility model, the primary side coil and the secondary side coil on the first core column, the second core column and the third core column of the transformer are alternately wound.

[0029] In the embodiment of the utility model, the coils on the first core column, the second core column and the third core column of the resonant inductance are wound in the same direction as the primary side coil and the secondary side coil on the first core column, the second core column and the third core column of the transformer.

[0030] In the embodiment of the utility model, the air gap of the first core column, the second core column and the third core column of the resonant inductance is greater than the air gap of the first core column, the second core column and the third core column of the transformer.

[0031] To make the above-mentioned features and advantages of this utility model more apparent and understandable, specific embodiments are described below, and detailed descriptions are provided in conjunction with the accompanying drawings. Attached Figure Description

[0032] Figure 1 A schematic block diagram of a multiphase LLC resonant converter according to an embodiment of the present invention is shown.

[0033] Figure 2 A schematic diagram of the circuit structure of a multiphase LLC resonant converter according to an embodiment of the present invention is shown.

[0034] Figure 3 Show Figure 2 A schematic diagram of the waveforms of each current in the multiphase LLC resonant converter of the embodiment;

[0035] Figure 4 A schematic diagram of the circuit structure of a multiphase LLC resonant converter according to another embodiment of the present invention is shown.

[0036] Figure 5 This diagram shows the structure of the switching circuit according to an embodiment of the present invention.

[0037] Figure 6 Show Figure 5 A schematic diagram of the gate-source voltage signal waveform in the embodiment;

[0038] Figure 7 Show Figure 5 A schematic diagram of the waveforms of the first voltage signal and the fourth voltage signal in the embodiment;

[0039] Figure 8 Show Figure 5 A schematic diagram of the drain-source voltage signal and magnetizing current waveforms in the embodiment;

[0040] Figure 9 This diagram shows the structural schematic of the rectifier circuit according to an embodiment of the present invention;

[0041] Figure 10 Show Figure 9 A schematic diagram of the drain-source voltage signal in the embodiment;

[0042] Figure 11A A three-dimensional schematic diagram of the magnetic core structure of the resonant inductor and transformer according to an embodiment of the present invention is shown.

[0043] Figure 11B Show Figure 11A A three-dimensional schematic diagram of the magnetic core structure and its coil in the embodiment;

[0044] Figure 12A yes Figure 11A A side view of the magnetic core structure in the embodiment;

[0045] Figure 12B is Figure 11B A side view schematic diagram of a magnetic core structure and its coils of an embodiment;

[0046] Figure 13 shows Figure 11B and Figure 12B A winding schematic diagram of a primary side coil and a secondary side coil of a transformer of an embodiment;

[0047] Figure 14 shows that there is Figure 11A and Figure 12A A structure schematic diagram of a resonant inductance and an air gap in a core column of a transformer of an embodiment.

[0048] Explanation of reference signs

[0049] 100, 200A, 200B: multiphase LLC resonant converter

[0050] 110, 210, 310: switching circuit

[0051] 120, 220A, 220B, 320: resonant cavity

[0052] 122: resonant circuit

[0053] 124, Tr1, Tr2, Tr3: transformer

[0054] 130, 230, 330: rectifying circuit

[0055] 212, SW11-SW16, SW21-SW24: switching component

[0056] 332: switching component group

[0057] 801, 802, 803A, 803B, 1001: signal waveform

[0058] 400: integrated magnetic core structure

[0059] 410: first cover plate

[0060] 420: second cover plate

[0061] 430: intermediate layer plate

[0062] 441, 451: first core column

[0063] 442, 452: second core column

[0064] 443, 453: third core column

[0065] 1301, 1302, 1303: coil group

[0066] C: reference axis

[0067] Cr, Cr1, Cr2, Cr3: resonance capacitance

[0068] GND: second voltage

[0069] GP41, GP42, GP43, GP51, GP52, GP53: air gap

[0070] ILm: magnetizing current

[0071] Iph1-Iph3: three-phase current

[0072] Ipri: primary-side current

[0073] Isec: secondary-side current

[0074] Lm: magnetizing inductance

[0075] Lr, Lr1, Lr2, Lr3: resonance inductance

[0076] P: primary-side coil

[0077] S: secondary-side coil

[0078] td: dead time

[0079] Vds: drain-source voltage signal

[0080] Vgs1-Vgs6: gate-source voltage signal

[0081] Vin: input voltage

[0082] Vo: first voltage

[0083] Vout: output voltage

[0084] Vs1-Vs4: control signal

[0085] X, Y, Z: direction DETAILED DESCRIPTION

[0086] The following embodiments are provided to illustrate the present application in detail, but the present application is not limited to the embodiments provided, and the embodiments provided can be appropriately combined. The terms "coupling / coupled" or "connecting / connected" used in the specification (including claims) of the present application can refer to any direct or indirect connection. For example, "the first device is coupled to the second device" should be interpreted as "the first device is directly connected to the second device" or "the first device is indirectly connected to the second device through other devices or connection means". In addition, the term "signal" can refer to current, voltage, charge, temperature, data, electromagnetic wave, or any one or more signals.

[0087] Figure 1 A schematic block diagram of a multiphase LLC resonant converter according to an embodiment of the present application is shown. Please refer to Figure 1 The multiphase LLC resonant converter 100 includes a switching circuit 110, a resonant tank 120, and a rectifier circuit 130. The resonant tank 120 includes a resonant circuit 122 and a transformer 124. The switching circuit 110 is configured at a primary side of the transformer 124, and the rectifier circuit 130 is configured at a secondary side of the transformer 124. The switching circuit 110 has a half-bridge structure, and the rectifier circuit 130 has a full-bridge structure.

[0088] The resonant circuit 122 includes a plurality of resonant inductors Lr and a plurality of resonant capacitors Cr. In an embodiment ( Figure 2 ), the resonant inductors Lr are connected in a delta connection. In another embodiment ( Figure 4 ), the resonant inductors Lr and the resonant capacitors Cr are connected in a delta connection.

[0089] In the present embodiment, the multiphase LLC resonant converter 100, for example, is a three-phase LLC resonant converter, and is used as a DC / DC power converter to convert a direct current input voltage Vin into a direct current output voltage Vout.

[0090] The multiphase LLC resonant converter 100 can be applied to at least a circuit architecture of a charging pile, an energy storage system, and an artificial intelligence server.

[0091] The present application is not limited to the application level of the multiphase LLC resonant converter 100.

[0092] In the present embodiment, since the switching circuit 110 has a half-bridge structure and the rectifier circuit 130 has a full-bridge structure, in the application of low voltage and large current, the multiphase LLC resonant converter 100 can solve the problem of large coil loss at the primary side and the secondary side of the transformer in the half-bridge half-bridge architecture, and solve the problem of large core loss of the transformer in the full-bridge full-bridge architecture, so as to balance the coil loss and the core loss.

[0093] In addition, in the embodiment, the resonant inductor Lr is connected in a delta connection, or the resonant inductor Lr and the resonant capacitor Cr are connected in a delta connection, cooperating with the half-bridge full-bridge architecture, so that the multi-phase LLC resonant converter 100 has good current balance capability when there is an error in the passive components (such as the resonant inductor Lr or the resonant capacitor Cr), in addition to reducing the core loss.

[0094] The following describes various different embodiments of the circuit structure of the multi-phase LLC resonant converter. The utility model is not limited to the provided embodiments.

[0095] Figure 2 A circuit structure schematic diagram of the multi-phase LLC resonant converter of the embodiment of the utility model is shown. Figure 3 A circuit structure schematic diagram of the multi-phase LLC resonant converter of the embodiment of the utility model is shown. Figure 2 A waveform schematic diagram of each current in the multi-phase LLC resonant converter of the embodiment is shown. Please refer to Figure 2 A waveform schematic diagram of each current in the multi-phase LLC resonant converter of the embodiment is shown. Please refer to Figure 3 The multi-phase LLC resonant converter 200A includes a switching circuit 210, a resonant cavity 220A, and a rectifier circuit 230. The resonant cavity 220A includes a resonant circuit and transformers Tr1-Tr3. The resonant circuit includes a plurality of resonant inductors Lr1-Lr3 and a plurality of resonant capacitors Cr1-Cr3. The resonant inductors Lr1-Lr3 are connected in a delta connection.

[0096] The switching circuit 210 includes a plurality of switching components 212 connected in a star connection. Each switching component 212 can be a metal oxide transistor, having a parasitic diode and a parasitic capacitor. The switching circuit 210, as a power switch, has a half-bridge architecture, and can be used to generate a square wave with a bias of Vin / 2, and output three-phase currents Iph1-Iph3 as shown in Figure 3 In addition, in the embodiment, the resonant inductor Lr is connected in a delta connection, or the resonant inductor Lr and the resonant capacitor Cr are connected in a delta connection, cooperating with the half-bridge full-bridge architecture, so that the multi-phase LLC resonant converter 100 has good current balance capability when there is an error in the passive components (such as the resonant inductor Lr or the resonant capacitor Cr), in addition to reducing the core loss. Figure 3

[0097] A circuit structure schematic diagram of the multi-phase LLC resonant converter of another embodiment of the utility model is shown. Please refer to Figure 4 A circuit structure schematic diagram of the multi-phase LLC resonant converter of another embodiment of the utility model is shown. Please refer to Figure 2 The circuit structure of the multi-phase LLC resonant converter 200B is similar to that of the multi-phase LLC resonant converter 200A, but in the embodiment, the resonant capacitors Cr1-Cr3 and the resonant inductors Lr1-Lr3 are connected in a delta connection. In addition, the waveforms of each current in the multi-phase LLC resonant converter 200B are also similar to those shown in Figure 4 Figure 4 Figure 2 Figure 4 The circuit structure of the multi-phase LLC resonant converter 200B is similar to that of the multi-phase LLC resonant converter 200A, but in the embodiment, the resonant capacitors Cr1-Cr3 and the resonant inductors Lr1-Lr3 are connected in a delta connection. In addition, the waveforms of each current in the multi-phase LLC resonant converter 200B are also similar to those shown in Figure 3 .​​​

[0098] The following describes the switch control of the primary side. Figure 5 A structure diagram of a switch circuit of an embodiment of the utility model is shown. Figure 6 A structure diagram of a switch circuit of an embodiment of the utility model is shown. Figure 5 A waveform diagram of the gate-source voltage signal of the embodiment is shown. Please refer to Figure 5 A waveform diagram of the gate-source voltage signal of the embodiment is shown. Please refer to Figure 6 The switch circuit 310 has a half-bridge structure and is arranged at the primary side of the resonant cavity 320. The switch circuit 310 comprises a plurality of switch components SW11-SW16. The switch components SW11-SW16 are connected in a star connection. Each of the switch components SW11-SW16 can be a metal oxide transistor, having a parasitic diode and a parasitic capacitor.

[0099] The gate-source voltage signals Vgs1-Vgs6 of the switch components SW11-SW16 are complementary to each other. For example, the phase difference between the first voltage signal Vgs1 and the fourth voltage signal Vgs4 is 180 degrees, the phase difference between the second voltage signal Vgs2 and the fifth voltage signal Vgs5 is 180 degrees, and the phase difference between the third voltage signal Vgs3 and the sixth voltage signal Vgs6 is 180 degrees, indicating that the gate-source voltage signals Vgs1-Vgs6 are complementary to each other.

[0100] In addition, the phase difference between the first voltage signal Vgs1, the second voltage signal Vgs2 and the third voltage signal Vgs3 is 120 degrees. The phase difference between the fourth voltage signal Vgs4, the fifth voltage signal Vgs5 and the sixth voltage signal Vgs6 is 120 degrees.

[0101] In the embodiment, there is a dead time td between the complementary gate-source voltage signals, as shown in Figure 7 to prevent the switch components SW11, SW14, the switch components SW12, SW15 or the switch components SW13, SW16 from being simultaneously turned on. Figure 7 A waveform diagram of the gate-source voltage signal of the embodiment is shown. Please refer to Figure 5 A waveform diagram of the gate-source voltage signal of the embodiment is shown. Please refer to Figure 7 A waveform diagram of the gate-source voltage signal of the embodiment is shown. Please refer to Figure 7 A waveform diagram of the gate-source voltage signal of the embodiment is shown. Please refer to

[0102] Figure 8 A waveform diagram of the gate-source voltage signal of the embodiment is shown. Please refer to Figure 5 A waveform diagram of the gate-source voltage signal of the embodiment is shown. Please refer to Figure 7 A waveform diagram of the gate-source voltage signal of the embodiment is shown. Please refer to Figure 8In the embodiment, the size of the dead time td depends on the parasitic capacitance values of the switching components on the primary side and the secondary side and the magnetizing inductance value of the transformer.

[0103] For example, in Figure 8 , the signal waveform 801 shows the current change of the magnetizing inductance ILm with a smaller magnetizing inductance value, and the signal waveform 802 shows the current change of the magnetizing inductance ILm with a larger magnetizing inductance value.

[0104] When the magnetizing inductance is small, the drain-source voltage signal Vds of the switching components SW11-SW16 on the primary side can be discharged to 0 volts quickly, as shown in the signal waveform 803B, and thus the dead time td is small. The signal waveform 803B is an enlarged schematic view of the signal waveform 803A when the magnetizing inductance is small. The signal waveform 803B indicates that the switching components SW11-SW16 have a zero-voltage switching function.

[0105] On the other hand, when the magnetizing inductance is large, a longer dead time td is needed to discharge the drain-source voltage signal Vds to 0 volts, as shown in the signal waveform 803B. Therefore, the dead time td is set to be large corresponding to the large magnetizing inductance, so that the switching components SW11-SW16 also have a zero-voltage switching function.

[0106] The following describes the switching control on the secondary side. Figure 9 A structure schematic view of the rectifier circuit of the embodiment of the utility model is shown. Figure 10 A structure schematic view of the rectifier circuit of the embodiment of the utility model is shown. Figure 9 A waveform schematic view of the drain-source voltage signal of the embodiment is shown. Please refer to Figure 9 and Figure 10 The rectifier circuit 330 has a full-bridge structure and is arranged on the secondary side of the resonant cavity 320. The rectifier circuit 310 includes a plurality of switching component groups 332. Each switching component group 332 is coupled between a first voltage Vo and a second voltage GND and is controlled by a plurality of control signals Vs1-Vs4. The first voltage Vo is, for example, the direct-current output power voltage Vout of the multi-phase LLC resonant converter 100, and the second voltage GND is, for example, a ground voltage, but the utility model is not limited thereto.

[0107] Each switching component group 332 includes switching components SW21-SW24. Each switching component SW21-SW24 can be a metal oxide transistor and has a parasitic diode and a parasitic capacitance. The switching components SW21-SW24 are respectively controlled by the control signals Vs1-Vs4. A driver (not shown) for controlling the switching components SW21-SW24 can output the control signals Vs1-Vs4 according to the drain-source voltage signal Vds to determine whether to turn on the switching components SW21-SW24.

[0108] For example, when the drain-source voltage signal Vds drops below 0 volts, as shown in signal waveform 1001, the driver detects a negative voltage. At this time, the driver outputs control signals Vs1 to Vs4 to control the switching components SW21 to SW24 to turn on. That is, when the drain-source voltage signal Vds of the switching components SW21 to SW24 in the switching component group 332 is less than the reference voltage, the control signals Vs1 to Vs4 control the switching components SW21 to SW24 in the switching component group 332 to turn on. In this example, the reference voltage is set to 0 volts, but this invention is not limited thereto.

[0109] The following explains the core structure of resonant inductors and transformers. Figure 11A This is a three-dimensional schematic diagram showing the magnetic core structure of the resonant inductor and transformer according to an embodiment of the present invention. Figure 11B Show Figure 11A A three-dimensional schematic diagram of the magnetic core structure and its coil in the embodiment.

[0110] Figure 12A yes Figure 11A A side view of the magnetic core structure in the embodiment. Figure 12B yes Figure 11B A side view of the magnetic core structure and its coil in the embodiment.

[0111] Please refer to Figures 11A to 12B ,by Figure 1 Taking a resonant inductor Lr and a transformer 124 as an example, the magnetic core of the resonant inductor Lr and the magnetic core of the transformer 124 are integrated to form an integrated magnetic core structure 400. The integrated magnetic core structure 400 includes a first cover plate 410, a second cover plate 420, and an intermediate layer plate 430. The first core post 441, the second core post 442, and the third core post 443 of the resonant inductor Lr are located between the first cover plate 410 and the intermediate layer plate 430, and are not coupled to each other. The first core post 451, the second core post 452, and the third core post 453 of the transformer 124 are located between the intermediate layer plate 430 and the second cover plate 420, and are not coupled to each other. The core posts of the resonant inductor Lr and the core posts of the transformer 124 are also not coupled to each other.

[0112] In this embodiment, the lower cover of the first core post 441, the second core post 442, and the third core post 443 of the resonant inductor Lr is an intermediate layer plate 430, and the upper cover of the first core post 451, the second core post 452, and the third core post 453 of the transformer 124 is an intermediate layer plate 430. That is, the lower cover of the resonant inductor Lr and the upper cover of the transformer 124 are both intermediate layer plates 430, so the two are integrated together to form an integrated magnetic core structure 400. Compared with a non-integrated magnetic core structure, the lower cover of the resonant inductor and the upper cover of the transformer are two different covers. The design of the integrated magnetic core structure 400 can not only reduce the volume of the resonant inductor Lr and the transformer 124, but also reduce the loss of magnetic components.

[0113] On the other hand, the coils on the first core column 441, the second core column 442 and the third core column 443 of the resonant inductor Lr are wound in the same direction, for example, all clockwise or all counterclockwise. The primary side coils and the secondary side coils on the first core column 451, the second core column 452 and the third core column 453 of the transformer 124 are wound in the same direction. Moreover, the coils of the resonant inductor Lr and the primary side coils and the secondary side coils of the transformer 124 are also wound in the same direction.

[0114] Figure 13 The winding schematic diagram of the primary side coils and the secondary side coils of the transformer of the embodiment is shown in Figure 11B and Figure 12B The winding schematic diagram of the primary side coils and the secondary side coils of the transformer of the embodiment is shown in Figure 13 , the primary side coils and the secondary side coils of the transformer 124 are marked as P and S respectively, the primary side coils P and the secondary side coils S are symmetrically wound with reference to the reference axis C. Moreover, the primary side coils P and the secondary side coils S are alternately wound on the upper and lower sides of the reference axis C.

[0115] In the three-phase architecture, the circuit is easy to cause the unevenness of the current of each phase due to the inconsistent size of the stray components on the line, so the winding of the transformer coils adopts the symmetric winding method shown in Figure 13 , and the primary side coils P and the secondary side coils S are arranged in an alternating manner, so that the loss caused by the alternating resistance is small.

[0116] Figure 14 The structure schematic diagram of the air gap in the core column of the resonant inductor and the transformer of the embodiment is shown in Figure 11A and Figure 12A The structure schematic diagram of the air gap in the core column of the resonant inductor and the transformer of the embodiment is shown in Figure 14 , the middle of the first core column 441, the second core column 442 and the third core column 443 of the resonant inductor Lr respectively exists the air gap GP41, GP42, GP43; the middle of the first core column 451, the second core column 452 and the third core column 453 of the transformer 124 respectively exists the air gap GP51, GP52, GP53. The position of the above-mentioned air gap is not limited to the utility model.

[0117] In the embodiment, since the magnetic flux path generated by the second core column 442 of the resonant inductor Lr is longer, in order to ensure the inductance on each core column is consistent, the air gap GP42 of the second core column 442 is designed to be smaller than the air gap GP41 of the first core column 441 and the air gap GP43 of the third core column 443, and the air gap GP41 of the first core column 441 and the air gap GP43 of the third core column 443 are designed to be equal, that is, GP42<GP43=GP41. The air gap size relationship of each core column of the transformer 124 can also be designed in a similar manner, that is, GP52<GP53=GP51.

[0118] In addition, in the embodiment, since the air gap is located at the middle position of each core column, the coil near the air gap can use a Litz wire coil to reduce the AC loss caused by the air gap to the coil.

[0119] On the other hand, in the embodiment, since the effective cross-sectional area of the resonant inductor Lr is the same as that of the transformer 124, and the inductance of the resonant inductor Lr is smaller than that of the transformer 124, the air gaps of the first core column 441, the second core column 442 and the third core column 443 of the resonant inductor Lr can be designed to be larger than the air gaps of the first core column 451, the second core column 452 and the third core column 453 of the transformer 124.

[0120] In summary, in the embodiment of the utility model, since the switching circuit has a half-bridge structure and the rectifier circuit has a full-bridge structure, in the application of low voltage and large current, the multi-phase LLC resonant converter can solve the problem of large coil loss on the primary side and the secondary side of the transformer in the half-bridge half-bridge structure, and solve the problem of large magnetic core loss in the full-bridge full-bridge structure, so as to balance the coil loss and the magnetic core loss. In addition, the resonant inductor and the resonant capacitor are connected in a delta connection, which cooperates with the half-bridge full-bridge structure to reduce the magnetic core loss, and when there is an error in the passive component, the multi-phase LLC resonant converter also has good current balance capability.

[0121] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the utility model, but not to limit them; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the utility model.

Claims

1. A multiphase LLC resonant converter, characterized in that, include: A resonant cavity includes a resonant circuit and a transformer, wherein the resonant circuit includes multiple resonant inductors, and the multiple resonant inductors are connected in a delta configuration. A switching circuit, configured on the primary side of the transformer, and having a half-bridge structure; and The rectifier circuit is configured on the secondary side of the transformer and has a full-bridge structure.

2. The multiphase LLC resonant converter according to claim 1, characterized in that, The resonant circuit also includes multiple resonant capacitors, and the multiple resonant inductors and the multiple resonant capacitors are connected in a delta configuration.

3. The multiphase LLC resonant converter according to claim 1, characterized in that, The switching circuit includes multiple switching components, and the gate-source voltage signals of the multiple switching components are complementary to each other.

4. The multiphase LLC resonant converter according to claim 3, characterized in that, There is a dead time between the complementary gate-source voltage signals.

5. The multiphase LLC resonant converter according to claim 4, characterized in that, The magnitude of the dead time depends on the parasitic capacitance values ​​of the switching components on the primary and secondary sides and the magnetizing inductance value of the transformer.

6. The multiphase LLC resonant converter according to claim 3, characterized in that, The gate-source voltage signal includes a first voltage signal, a second voltage signal, a third voltage signal, a fourth voltage signal, a fifth voltage signal, and a sixth voltage signal, wherein the phase difference between the first voltage signal and the fourth voltage signal is 180 degrees, the phase difference between the second voltage signal and the fifth voltage signal is 180 degrees, and the phase difference between the third voltage signal and the sixth voltage signal is 180 degrees.

7. The multiphase LLC resonant converter according to claim 6, characterized in that, The phase difference between the first voltage signal, the second voltage signal, and the third voltage signal is 120 degrees, and the phase difference between the fourth voltage signal, the fifth voltage signal, and the sixth voltage signal is 120 degrees.

8. The multiphase LLC resonant converter according to claim 3, characterized in that, The plurality of switch assemblies are connected in a star configuration.

9. The multiphase LLC resonant converter according to claim 1, characterized in that, The rectifier circuit includes multiple switch component groups, and each of the switch component groups is coupled between a first voltage and a second voltage and is controlled by multiple control signals.

10. The multiphase LLC resonant converter according to claim 9, characterized in that, When the drain-source voltage signal of the switch component in the switch component group is less than the reference voltage, the plurality of control signals control the switch component in the switch component group to turn on.

11. The multiphase LLC resonant converter according to claim 1, characterized in that, The magnetic core of the resonant inductor is integrated with the magnetic core of the transformer to form an integrated magnetic core structure, and the integrated magnetic core structure includes a first cover plate, a second cover plate, and an intermediate layer plate. The first, second, and third cores of the resonant inductor are located between the first cover plate and the intermediate layer plate, and the first, second, and third cores of the transformer are located between the intermediate layer plate and the second cover plate.

12. The multiphase LLC resonant converter according to claim 11, characterized in that, Each of the first, second, and third core posts of the resonant inductor has an air gap.

13. The multiphase LLC resonant converter according to claim 12, characterized in that, The air gap of the second core column is smaller than the air gap of the first core column and the air gap of the third core column.

14. The multiphase LLC resonant converter according to claim 12, characterized in that, The air gap of the first core post is equal to the air gap of the third core post.

15. The multiphase LLC resonant converter according to claim 12, characterized in that, The air gap exists in the middle of each of the core posts.

16. The multiphase LLC resonant converter according to claim 11, characterized in that, The first, second, and third cores of the resonant inductor are not coupled to each other.

17. The multiphase LLC resonant converter according to claim 11, characterized in that, The coils on the first, second, and third cores of the resonant inductor are wound in the same direction.

18. The multiphase LLC resonant converter according to claim 11, characterized in that, Each of the first, second, and third core columns of the transformer has an air gap.

19. The multiphase LLC resonant converter according to claim 18, characterized in that, The air gap of the second core column is smaller than the air gap of the first core column and the air gap of the third core column.

20. The multiphase LLC resonant converter according to claim 18, characterized in that, The air gap of the first core post is equal to the air gap of the third core post.

21. The multiphase LLC resonant converter according to claim 18, characterized in that, The air gap exists in the middle of each of the core posts.

22. The multiphase LLC resonant converter according to claim 11, characterized in that, The first core, the second core, and the third core of the transformer are not coupled to each other.

23. The multiphase LLC resonant converter according to claim 11, characterized in that, The primary and secondary coils on the first, second, and third core posts of the transformer are wound in the same direction.

24. The multiphase LLC resonant converter according to claim 11, characterized in that, The primary and secondary coils on the first, second, and third core columns of the transformer are symmetrically wound with reference to a reference axis.

25. The multiphase LLC resonant converter according to claim 11, characterized in that, The primary and secondary coils on the first, second, and third core posts of the transformer are wound alternately.

26. The multiphase LLC resonant converter according to claim 11, characterized in that, The coils on the first, second, and third core posts of the resonant inductor are wound in the same direction as the primary and secondary coils on the first, second, and third core posts of the transformer.

27. The multiphase LLC resonant converter according to claim 11, characterized in that, The air gap of the first, second, and third cores of the resonant inductor is greater than the air gap of the first, second, and third cores of the transformer.

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