Power conversion device

Abstract

The application provides a power conversion device, which comprises a first capacitor, a second capacitor and a power module. The first capacitor and the second capacitor are connected in series. The power module is electrically connected to the first capacitor and the second capacitor, and comprises a circuit board, an absorption capacitor, a primary side switching circuit, a magnetic assembly and a secondary side circuit. The absorption capacitor, the primary side switching circuit, the magnetic assembly and the secondary side circuit are arranged on the circuit board. The primary side winding and the secondary side winding of the magnetic assembly are electrically connected to the primary side switching circuit and the secondary side circuit respectively. The capacitance of the first capacitor and the second capacitor is greater than the capacitance of the absorption capacitor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronic devices, and in particular to a power conversion device. BACKGROUND

[0002] In a data center using a high-power rack, a 48V DC bus is generally used. A primary converter module with a transformer can directly convert the 48V voltage into a low voltage used by a processor such as a CPU or a GPU. Such a primary converter module has a high efficiency. In some applications such as CPU flip-chip mounting or CPU package, the primary converter module must also meet the extreme requirements of high power density and low module height (such as less than 3 mm). However, due to the height of the capacitor in the converter module, the height of the overall converter module is difficult to meet the requirement of low module height.

[0003] Therefore, how to develop a power conversion device that can improve the above-mentioned prior art is a current urgent need. SUMMARY

[0004] The purpose of the present application is to provide a power conversion device, which separates at least part of the capacitor from the power module to reduce the height of the power conversion device, while improving the power density of the power module.

[0005] To achieve the above-mentioned purpose, the present application provides a power conversion device, comprising a first capacitor, a second capacitor and a power module. The first capacitor and the second capacitor are connected in series. The power module is electrically connected to the first capacitor and the second capacitor, and comprises a circuit board, an absorption capacitor, a primary side switching circuit, a magnetic assembly and a secondary side circuit. The absorption capacitor, the primary side switching circuit, the magnetic assembly and the secondary side circuit are arranged on the circuit board, and the primary side winding and the secondary side winding of the magnetic assembly are respectively electrically connected to the primary side switching circuit and the secondary side circuit. The capacitance of the first capacitor and the second capacitor is greater than the capacitance of the absorption capacitor.

[0006] To achieve the above-mentioned purpose, the present application further provides a power conversion device, comprising a first capacitor, a second capacitor, a primary side switching circuit and a power module. The first capacitor and the second capacitor are connected in series. The primary side switching circuit is connected in parallel with the first capacitor and the second capacitor. The power module is electrically connected to the first capacitor, the second capacitor and the primary side switching circuit, and comprises a circuit board, a magnetic assembly and a secondary side circuit. The magnetic assembly and the secondary side circuit are arranged on the circuit board, and the primary side winding and the secondary side winding of the magnetic assembly are respectively electrically connected to the primary side switching circuit and the secondary side circuit. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 FIG. 1 is a circuit structure schematic diagram of a power conversion device according to a first preferred embodiment of the present application.

[0008] Figure 2 FIG. 2 shows a circuit structure schematic diagram of a power conversion device according to a second preferred embodiment of the present application.Figure 1 Driving timing of each switch and rectifier component.

[0009] Figure 3 A perspective view of the power conversion device according to the first preferred embodiment of the present application.

[0010] Figure 4 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 3 A side view of the power conversion device according to the first preferred embodiment of the present application.

[0011] Figure 5 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 6 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 3 A perspective view of the power conversion device according to the first preferred embodiment of the present application.

[0012] Figure 7 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 1 A perspective view of the power conversion device according to the first preferred embodiment of the present application.

[0013] Figure 8 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 7 A perspective view of the power conversion device according to the first preferred embodiment of the present application.

[0014] Figure 9 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 10 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 1 A perspective view of the power conversion device according to the first preferred embodiment of the present application.

[0015] Figure 11 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 12 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 7 A perspective view of the power conversion device according to the first preferred embodiment of the present application.

[0016] Figure 13 A perspective view of the power conversion device according to the first preferred embodiment of the present application.

[0017] Figure 14 A perspective view of the power conversion device according to the first preferred embodiment of the present application.

[0018] Figure 15 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 16 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 14 A perspective view of the power conversion device according to the first preferred embodiment of the present application.

[0019] Figure 17 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 18 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 13 A perspective view of the power conversion device according to the first preferred embodiment of the present application.

[0020] Figure 19 A perspective view of the power conversion device according to the first preferred embodiment of the present application. Figure 20Fig. 1 is a schematic diagram of a magnetic core assembly of a magnetic assembly according to a preferred embodiment of the present application.

[0021] Figure 21 and Figure 22 Fig. 2 is a schematic diagram of the magnetic core assembly of the magnetic assembly of Fig. 1 with a first magnetic cover removed.

[0022] Legend:

[0023] 1: power conversion device

[0024] Vin+: positive input

[0025] Vin-: negative input

[0026] Vin: input voltage

[0027] Vo+: positive output

[0028] Vo-: negative output

[0029] Vo: output voltage

[0030] C1: first capacitor

[0031] C2: second capacitor

[0032] 10: power module

[0033] b: first capacitor midpoint

[0034] a: second end of first capacitor

[0035] c: second end of second capacitor

[0036] C3: snubber capacitor

[0037] 11: primary side switching circuit

[0038] Q1: first switch

[0039] Q2: second switch

[0040] M: switching midpoint

[0041] 12: magnetic assembly

[0042] Np: primary winding

[0043] Ns1: first secondary winding

[0044] Ns2: second secondary winding

[0045] 13: secondary side circuit

[0046] A: first end

[0047] B: second end

[0048] C: third end

[0049] S1, S3: first rectifying component

[0050] S2, S4: second rectifying component

[0051] VQ1, VQ2, VS1, VS2, VS3, VS4: drive signal

[0052] VNp: across voltage

[0053] D: duty cycle

[0054] 14: circuit board

[0055] 141: first face

[0056] 142: second face

[0057] 100: carrier board

[0058] Co: output capacitor

[0059] 15: drive circuit

[0060] 16: pin

[0061] 1a: power conversion device

[0062] 10a: power module

[0063] C31: first absorption capacitor

[0064] C32: second absorption capacitor

[0065] N: second capacitor midpoint

[0066] 2: power conversion device

[0067] C4: first capacitor

[0068] C5: second capacitor

[0069] 21: primary side switching circuit

[0070] 20: power module

[0071] e: capacitor midpoint

[0072] Q3: first switch

[0073] Q4: second switch

[0074] d: switch midpoint

[0075] D: first end

[0076] E: second end

[0077] 24: circuit board

[0078] 241: first surface

[0079] 242: second surface

[0080] 26: pin

[0081] 200: carrier board

[0082] 120: magnetic core assembly

[0083] 121: first magnetic cover

[0084] 122: second magnetic cover

[0085] 123: first magnetic column

[0086] 124: second magnetic column

[0087] 125: third magnetic column

[0088] 126: fourth magnetic column

[0089] 127: communication area

[0090] D1, D2: diode

[0091] 120a: magnetic core assembly

[0092] 121a: first magnetic cover

[0093] 122a: second magnetic cover

[0094] 123a: first magnetic column

[0095] 124a: second magnetic column

[0096] 125a: third magnetic column DETAILED DESCRIPTION

[0097] Some typical embodiments embodying features and advantages of the present application are described in detail in the following description. It should be appreciated that the present application can be embodied in various ways without departing from the spirit or central characteristics thereof, and that the description and drawings are to be considered illustrative only and not restrictive.

[0098] Figure 1 The circuit structure schematic diagram of the power conversion device of the first preferred embodiment of the present application is shown in FIG. 1. As shown in the figure, the power conversion device comprises a carrier board 200, a circuit board 24, a magnetic core assembly 120, a first magnetic cover 121, a second magnetic cover 122, a first magnetic column 123, a second magnetic column 124, a third magnetic column 125, a fourth magnetic column 126, a communication area 127, a first diode D1, a second diode D2, a first pin 26, and a second pin 26. Figure 1As shown, the power conversion device 1 receives an input voltage Vin via a positive input terminal Vin+ and a negative input terminal Vin-, and outputs an output voltage Vo via a positive output terminal Vo+ and a negative output terminal Vo-. The power conversion device 1 comprises a first capacitor C1, a second capacitor C2, and a power module 10, wherein the first capacitor C1 and the second capacitor C2 are configured to divide the input voltage Vin. The first capacitor C1 and the second capacitor C2 are connected in series, a first end of the first capacitor C1 and a first end of the second capacitor C2 are electrically connected to a first capacitor midpoint b, a second end a of the first capacitor C1 is electrically connected to the positive input terminal Vin+, and a second end c of the second capacitor C2 is electrically connected to the negative input terminal Vin-.

[0099] The power module 10 comprises a snubber capacitor C3, a primary side switching circuit 11, a magnetic assembly 12, and a secondary side circuit 13, and has a first end A, a second end B, and a third end C. The first end A, the second end B, and the third end C of the power module 10 are electrically connected to the second end a of the first capacitor C1, the first capacitor midpoint b, and the second end c of the second capacitor C2, respectively. Two ends of the snubber capacitor C3 are electrically connected to the first end A and the third end C of the power module 10, respectively, and two ends of the primary side switching circuit 11 are electrically connected to the first end A and the third end C of the power module 10, respectively, i.e., the snubber capacitor C3 and the primary side switching circuit 11 are connected in parallel. The primary side switching circuit 11 comprises a first switch Q1 and a second switch Q2 connected in series, and has a switching midpoint M between the first switch Q1 and the second switch Q2. The snubber capacitor C3 can absorb voltage stress when the first switch Q1 and the second switch Q2 are turned on and turned off.

[0100] In this embodiment, the magnetic assembly 12 comprises a primary side winding Np, a first secondary side winding Ns1, and a second secondary side winding Ns2. Two ends of the primary side winding Np are electrically connected to the switching midpoint M and the second end B of the power module 10, respectively. The primary side winding Np is electromagnetically coupled to the first secondary side winding Ns1 and the second secondary side winding Ns2. The first secondary side winding Ns1 and the second secondary side winding Ns2 each have a first end and a second end. The second end of the first secondary side winding Ns1, the first end of the second secondary side winding Ns2, and the first end of the primary side winding Np are the same-named ends. The second end of the first secondary side winding Ns1 and the second end of the second secondary side winding Ns2 are the different-named ends, and are electrically connected to each other to form a center tap point, wherein the center tap point is electrically connected to the positive output terminal Vo+.

[0101] In some embodiments, the secondary circuit 13 includes a first rectifier component and a second rectifier component. The first rectifier component is electrically connected between a first terminal of the first secondary winding Ns1 and the negative output terminal Vo+, and includes two first rectifier components S1 and S3 connected in parallel. The second rectifier component is electrically connected between a first terminal of the second secondary winding Ns2 and the negative output terminal Vo-, and includes two first rectifier components S2 and S4 connected in parallel. These rectifier components S1, S2, S3, and S4 may be, for example, but not limited to, MOSFETs or diodes. The first terminals of the first rectifier components S1 and S3 are electrically connected to the first terminals of the second rectifier components S2 and S4, wherein the first terminals of the first rectifier components S1 and S3 and the first terminals of the second rectifier components S2 and S4 are the same electrode, for example, the source electrode. The second ends (e.g., drains) of the first rectifier components S1 and S3 are electrically connected to the first end of the first secondary winding Ns1, and the second ends (e.g., drains) of the second rectifier components S2 and S4 are electrically connected to the first end of the second secondary winding Ns2. Therefore, the first rectifier components S1 and S3, the second rectifier components S2 and S4, the first secondary winding Ns1 and the second secondary winding Ns2 can form a closed loop.

[0102] Figure 1 The driving timing of each switch and rectifier component is as follows: Figure 2 As shown. The drive signal VQ1 received by the first switch Q1 and the drive signal VQ2 received by the second switch Q2 are 180 degrees out of phase, and the duty cycles of drive signals VQ1 and VQ2 are approximately equal (in Figure 2 In this context, the symbol D represents the duty cycle of drive signals VQ1 and VQ2. Furthermore, the drive signals VS1 and VS3 received by the first rectifier components S1 and S3 are complementary to drive signal VQ2, and the drive signals VS2 and VS4 received by the second rectifier components S2 and S4 are complementary to drive signal VQ1. The bridging voltage VNp across the primary winding Np is a three-level alternating voltage, meaning it has three voltage levels: +Vin / 2, 0, and -Vin / 2. In some embodiments, when the duty cycle of drive signals VQ1 and VQ2 is close to or equal to 50%, the bridging voltage VNp is a two-level alternating voltage, meaning it has two voltage levels: +Vin / 2 and -Vin / 2.

[0103] Figure 3 This is a three-dimensional structural diagram of the power conversion device according to a first preferred embodiment of the present invention. Figure 4 for Figure 3 Side view of the power conversion device. Figure 5 and Figure 6 for Figure 3 A three-dimensional structural diagram of the power module from different perspectives. (See attached diagram.) Figure 3 ,Figure 5 and Figure 6 As shown, the power module 10 also includes a circuit board 14, on which the absorption capacitor C3, primary-side switching circuit 11, magnetic component 12, and secondary-side circuit 13 of the power module 10 are all disposed. The power conversion device 1 also includes a carrier board 100, on which the first capacitor C1, the second capacitor C2, and the power module 10 are all disposed. The first capacitor C1 and the second capacitor C2 are electrically connected to the power module 10 via the carrier board 100 (in... Figure 1 (The corresponding dashed lines indicate the portions electrically connected via the carrier board 100). Since the capacitance values ​​of the first capacitor C1 and the second capacitor C2 are both greater than those of the absorption capacitor C3, and their volumes are also larger, a larger package is generally chosen to account for cost and area. Placing the first capacitor C1 and the second capacitor C2 on the circuit board 14 would significantly increase the overall height of the power conversion device 1. Therefore, separating the first capacitor C1 and the second capacitor C2 from the power module 10 can effectively reduce the overall height of the power conversion device 1 (e.g., ...). Figure 4 (As shown), this can simultaneously increase the power density of the power module 10. In some embodiments, the first capacitor C1 and the second capacitor C2 can each be composed of multiple capacitors connected in parallel.

[0104] In some embodiments, such as Figure 5 and Figure 6 As shown, on the first side 141 of the circuit board 14, the absorption capacitor C3, the first and second switches Q1 and Q2, the rectifier components S3 and S4, and the magnetic component 12 are arranged in sequence, and the output capacitor Co is adjacent to the rectifier component S4 and the magnetic component 12. On the second side 142 of the circuit board 14, the rectifier components S1 and S2 are disposed between the first terminal A, the second terminal B, and the third terminal C and the magnetic component 12, the negative output terminal Vo- is adjacent to one side of the rectifier components S1 and S2 and the magnetic component 12, and the positive output terminal Vo+ is adjacent to the other side of the magnetic component 12. In some embodiments, the power module 10 further includes a drive circuit 15 and a plurality of pins 16 disposed on the second side 142 of the circuit board 14. The drive circuit 15 is adjacent to the rectifier components S1 and S2, and the plurality of pins 16 are disposed on both sides of the drive circuit 15, wherein the pins 16 are configured for control detection signals. The placement of the various components in the power module 10 shown in this invention on the circuit board 14 is merely an example and is not actually limited.

[0105] In the foregoing embodiments, the absorption capacitor C3 is composed of a single capacitor; however, its number is not limited in practice and depends on the capacitance value of the capacitors used. The following example illustrates the case where the absorption capacitor C3 is composed of two capacitors. Figure 7 for Figure 1 The circuit structure diagram of the power conversion device variation shown is illustrated.Figure 7 As shown, in this variant, in the power conversion device 1a, Figure 1 the similar components of the power conversion device 1a are denoted by the same reference numerals, and thus will not be described again. Compared with the power conversion device 1, Figure 1 the power conversion device 1a, Figure 7 the absorption capacitor of the power module 10a of the power conversion device 1a comprises a first absorption capacitor C31 and a second absorption capacitor C32 connected in series. The first absorption capacitor C31 and the second absorption capacitor C32 have a second capacitor midpoint N therebetween, wherein the second capacitor midpoint N is electrically connected to the second end B of the power module 10a. The perspective structure of the power conversion device 1a of this variant is shown in Figure 8 .

[0106] In addition, in the foregoing embodiments, the power conversion device only comprises one power module, but in fact the number of power modules is not limited. For example, in some embodiments, as shown in Figure 9 , the power conversion device 1 in the first preferred embodiment can comprise a plurality of power modules 10. The plurality of first ends A of the plurality of power modules 10 are electrically connected to each other, the plurality of second ends B of the plurality of power modules 10 are electrically connected to each other, and the plurality of third ends C of the plurality of power modules 10 are electrically connected to each other. The perspective structure of the power conversion device 1 comprising the plurality of power modules 10 is shown in Figure 10 , wherein the corresponding first ends A, second ends B or third ends C are electrically connected to each other via the carrier board 100, and in Figure 9 , for the sake of simplicity of the drawing, the connection lines thereof are not shown.

[0107] Of course, as shown in Figure 11 , the power conversion device 1a can also comprise a plurality of power modules 10a. Similarly, the plurality of first ends A of the plurality of power modules 10a are electrically connected to each other, the plurality of second ends B of the plurality of power modules 10a are electrically connected to each other, and the plurality of third ends C of the plurality of power modules 10a are electrically connected to each other. The perspective structure of the power conversion device 1a comprising the plurality of power modules 10a is shown in Figure 12 , wherein the corresponding first ends A, second ends B or third ends C are electrically connected to each other via the carrier board 100, and in Figure 11 , for the sake of simplicity of the drawing, the connection lines thereof are not shown.

[0108] Figure 13 The circuit structure schematic diagram of the power conversion device of the second preferred embodiment of the present application is shown in Figure 13As shown, the power conversion device 2 receives an input voltage Vin via a positive input terminal Vin+ and a negative input terminal Vin-, and outputs an output voltage Vo via a positive output terminal Vo+ and a negative output terminal Vo-. The power conversion device 2 includes a first capacitor C4, a second capacitor C5, a primary side switching circuit 21, and a power module 20. The first capacitor C4 and the second capacitor C5 are connected in series, a first end of the first capacitor C4 and a first end of the second capacitor C5 are electrically connected to a capacitor midpoint e, a second end of the first capacitor C4 is electrically connected to the positive input terminal Vin+, and a second end of the second capacitor C5 is electrically connected to the negative input terminal Vin-. The primary side switching circuit 21 includes a first switch Q3 and a second switch Q4 connected in series between the positive input terminal Vin+ and the negative input terminal Vin-, and has a switching midpoint d between the first switch Q3 and the second switch Q4. The first capacitor C4 and the second capacitor C5 are configured to divide the input voltage Vin and absorb voltage stress when the first switch Q3 and the second switch Q4 are turned on and turned off.

[0109] The power module 20 is electrically connected to the first capacitor C4, the second capacitor C5, and the primary side switching circuit 21, and includes a magnetic assembly 12 and a secondary side circuit 13, and has a first end D and a second end E. The detailed structure of the magnetic assembly 12 and the secondary side circuit 13 is the same as that in the power module 10, and thus is not described again here. In this embodiment, the first end D of the power module 20 is electrically connected to the switching midpoint d and a first end of a primary winding Np of the magnetic assembly 12, and the second end E of the power module 20 is electrically connected to the capacitor midpoint e and a second end of the primary winding Np of the magnetic assembly 12. Figure 1

[0110] Figure 14 A perspective structural schematic diagram of a power conversion device according to a second preferred embodiment of the present application is shown in Figure 15 Figure 16 A perspective structural schematic diagram of a power module in the power conversion device according to the second preferred embodiment of the present application is shown in Figure 14 Figure 14 Figure 15 Figure 16 As shown in FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, and 100, the power module 20 further includes a circuit board 24, and the magnetic assembly 12 and the secondary side circuit 13 of the power module 20 are disposed on the circuit board 24. The power conversion device 2 further includes a carrier board 200, and the first capacitor C4, the second capacitor C5, the primary side switching circuit 21, and the power module 20 are disposed on the carrier board 200. The first capacitor C4, the second capacitor C5, and the primary side switching circuit 21 are electrically connected to the power module 20 via the carrier board 200 (the parts electrically connected via the carrier board 200 are represented by dashed lines in FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, and 100). By separating the first capacitor C4 and the second capacitor C5 from the power module 20, the overall height of the power conversion device 2 can be effectively reduced, and the power density of the power module 20 can be improved. Figure 13

[0111] In some embodiments, as shown in​​​​​​Figure 15 and Figure 16 As shown, on the first side 241 of the circuit board 24, rectifier components S3 and S4 and magnetic component 12 are arranged adjacent to each other, and the output capacitor Co is arranged adjacent to rectifier components S4 and magnetic component 12. On the second side 242 of the circuit board 24, rectifier components S1 and S2 are disposed between the first terminal D and the second terminal E and the magnetic component 12, the negative output terminal Vo- is arranged adjacent to one side of rectifier components S1 and S2 and magnetic component 12, and the positive output terminal Vo+ is arranged adjacent to the other side of magnetic component 12. In some embodiments, the power module 20 further includes a plurality of pins 26 disposed on the second side 242 of the circuit board 24, the plurality of pins 26 being disposed on both sides of the first terminal D and the second terminal E, wherein the pins 26 are configured to control detection signals. The arrangement positions of the various components on the circuit board 24 in the power module 20 shown in this invention are only for illustration and are not actually limited.

[0112] In addition, Figures 13 to 16 In the illustrated embodiment, the power conversion device 2 includes only one power module 20; however, in practice, the number of power modules 20 is not limited. For example, in some embodiments, such as Figure 17 As shown, the power conversion device 2 may include multiple power modules 20. Multiple first terminals D of the multiple power modules 20 are electrically connected to each other, and multiple second terminals E of the multiple power modules 20 are electrically connected to each other. The three-dimensional structure of the power conversion device 2 including multiple power modules 20 is shown below. Figure 18 As shown, the corresponding first terminal D or second terminal E are electrically connected to each other via the carrier plate 200, and in Figure 17 For the sake of simplicity, the connecting lines in the accompanying drawings are not shown.

[0113] In another embodiment, such as Figure 14 and Figure 18 The power conversion device shown also includes another circuit board (not shown). The first capacitor C4, the second capacitor C5, and the primary-side switching circuit 21 can all be mounted on this other circuit board, and then mounted together with the power module on the carrier board 200. The first capacitor C4, the second capacitor C5, and the primary-side switching circuit 21 are electrically connected to the power module 20 via the other circuit board and the carrier board 200, which can effectively reduce the overall height of the power conversion device and increase the power density of the power module.

[0114] Figure 19 This is an exploded structural diagram of the magnetic core assembly of the magnetic component according to a preferred embodiment of the present invention. Figure 20 This is a schematic diagram of the magnetic assembly of a preferred embodiment of the present invention when the first magnetic cover is removed. Figure 19 and Figure 20As shown, the magnetic assembly 12 comprises a magnetic core assembly 120, a primary winding Np, a first secondary winding Ns1 and a second secondary winding Ns2. The magnetic core assembly 120 comprises a first magnetic cover 121, a second magnetic cover 122, a first magnetic leg 123, a second magnetic leg 124, a third magnetic leg 125 and a fourth magnetic leg 126. The first magnetic leg 123 and the third magnetic leg 125 are oppositely arranged between the first magnetic cover 121 and the second magnetic cover 122, the second magnetic leg 124 and the fourth magnetic leg 126 are oppositely arranged between the first magnetic cover 121 and the second magnetic cover 122, and the first magnetic leg 123 and the third magnetic leg 125 are located between the second magnetic leg 124 and the fourth magnetic leg 126. The magnetic resistances of the second magnetic leg 124 and the fourth magnetic leg 126 are greater than those of the first magnetic leg 123 and the third magnetic leg 125 respectively, and the first magnetic leg 123, the second magnetic leg 124, the third magnetic leg 125 and the fourth magnetic leg 126 jointly define a communication region 127. Figure 20 In the magnetic assembly 12 shown in FIG. 1, the first magnetic cover 121 is not shown, so that the changes of the number, position and winding mode of the magnetic legs can be clearly shown.

[0115] In addition, the primary winding Np is wound on the first magnetic leg 123 and the third magnetic leg 125 through the communication region 127, and the magnetic flux directions of the first magnetic leg 123 and the third magnetic leg 125 are opposite. The first end of the first secondary winding Ns1 is threaded between the first magnetic leg 123 and the second magnetic leg 124, the second end of the first secondary winding Ns1 is threaded between the third magnetic leg 125 and the fourth magnetic leg 126, the first end of the second secondary winding Ns2 is threaded between the first magnetic leg 123 and the fourth magnetic leg 126, and the second end of the second secondary winding Ns2 is threaded between the second magnetic leg 124 and the third magnetic leg 125.

[0116] As can be seen from the above, since the magnetic resistances of the second magnetic leg 124 and the fourth magnetic leg 126 of the magnetic core assembly 120 of the embodiment are greater than those of the first magnetic leg 123 and the third magnetic leg 125 respectively, and the windings are arranged in a cross manner, the magnetic assembly 12 has the advantages of small alternating current ripple of the current flowing through the primary winding Np, the first secondary winding Ns1 and the second secondary winding Ns2, and strong current saturation resistance of the magnetic core.

[0117] In some embodiments, the second magnetic post 124 and the fourth magnetic post 126 include air gaps, while the first magnetic post 123 and the third magnetic post 125 may not include air gaps. However, this is not a limitation. In other embodiments, the first magnetic post 123 and the third magnetic post 125 may also include air gaps, provided that the lengths of the air gaps in the second magnetic post 124 and the fourth magnetic post 126 are greater than the lengths of the air gaps in the first magnetic post 123 and the third magnetic post 125, respectively. Furthermore, the air gap of each magnetic post may be located in the upper region of the corresponding magnetic post and adjacent to the first magnetic cover 121, but this is not a limitation. The air gap of each magnetic post may also be located in the lower region of the corresponding magnetic post and adjacent to the second magnetic cover 122, or the air gap of each magnetic post may be located in the middle region of the corresponding magnetic post.

[0118] In some embodiments, the primary winding Np is wound alternately around the first magnetic post 123 and the third magnetic post 125 in a figure-eight pattern via the connecting region 127, such that the magnetic flux directions on the first magnetic post 123 and the third magnetic post 125 are opposite. To further illustrate, the primary winding Np enters between the first magnetic post 123 and the fourth magnetic post 126, passes through the connecting region 127, exits between the second magnetic post 124 and the third magnetic post 125, and wraps around the third magnetic post 125. Then, it enters between the third magnetic post 125 and the fourth magnetic post 126, passes through the connecting region 127, and finally exits between the first magnetic post 123 and the second magnetic post 124. Therefore, the first end of the primary winding Np passes between the first magnetic post 123 and the fourth magnetic post 126, and the second end of the primary winding Np passes between the first magnetic post 123 and the second magnetic post 124, with the first and second ends of the primary winding Np located on the same side of the core assembly 120. Of course, in other embodiments, the winding method of the primary winding Np can also be changed to partially winding the primary winding Np onto the first magnetic post 123, and then the remaining portion of the primary winding Np is wound onto the third magnetic post 125 via the connecting region 127.

[0119] For example Figure 1 and Figure 7 As shown, the first rectifier component restricts the current direction of the first secondary winding Ns1, and the second rectifier component restricts the current direction of the second secondary winding Ns2, so that the current direction of the current flowing through the first secondary winding Ns1 and the current direction of the current flowing through the second secondary winding Ns2 are the same, both flowing from the first end of the corresponding secondary winding to the second end of the corresponding secondary winding. Figure 20 In the diagram, diodes D1 and D2 represent the first rectifier component and the second rectifier component, respectively. The arrows on the first secondary winding Ns1 and the second secondary winding Ns2 indicate the direction of the current. The current flows into the second secondary winding from the first end and out from the second end.

[0120] The first voltage across the first end and the second end of the first secondary winding Ns1 is 180 degrees out of phase with the second voltage across the first end and the second end of the second secondary winding Ns2. The current flowing through the first secondary winding Ns1 and the current flowing through the second secondary winding Ns2 generate alternating magnetic fluxes on the first magnetic column 123 and the third magnetic column 125 respectively, wherein the directions of the alternating magnetic fluxes on the first magnetic column 123 and the third magnetic column 125 are opposite, and the alternating magnetic fluxes on the first magnetic column 123 and the third magnetic column 125 are approximately equal, and each of the alternating magnetic fluxes is the alternating magnetic flux generated by the current flowing through the first secondary winding Ns1 minus the alternating magnetic flux generated by the current flowing through the second secondary winding Ns2. Moreover, the alternating magnetic flux generated by the first secondary winding Ns1 and the alternating magnetic flux generated by the second secondary winding Ns2 are approximately equally distributed to the second magnetic column 124 and the fourth magnetic column 126 by phase superposition, and the directions of the alternating magnetic fluxes on the second magnetic column 124 and the fourth magnetic column 126 are opposite. Furthermore, the direct current flowing through the first secondary winding Ns1 and the direct current flowing through the second secondary winding Ns2 generate direct magnetic fluxes on the first magnetic column 123, and the direct magnetic fluxes on the first magnetic column 123 are approximately equal. Moreover, the direct current flowing through the first secondary winding Ns1 and the direct current flowing through the second secondary winding Ns2 generate direct magnetic fluxes on the third magnetic column 125, and the direct magnetic fluxes on the third magnetic column 125 are approximately equal. Since the primary capacitor has the function of blocking direct current, the direct current flowing through the first secondary winding Ns1 and the direct current flowing through the second secondary winding Ns2 are approximately equal by the capacitor, so that the direct magnetic fluxes on the first magnetic column 123 and the third magnetic column 125 are approximately equal to zero. Moreover, the direct magnetic fluxes generated by the direct current flowing through the first secondary winding Ns1 and the direct current flowing through the second secondary winding Ns2 are in the same direction and are connected in series across the second magnetic column 124 and the fourth magnetic column 126, and the air gaps of the second magnetic column 124 and the fourth magnetic column 126 are used to prevent the saturation of the second magnetic column 124 and the fourth magnetic column 126. By using the primary capacitor, the direct current flowing through the first secondary winding Ns1 and the direct current flowing through the second secondary winding Ns2 are approximately equal. In some embodiments, the primary capacitor is a first capacitor and a second capacitor. In some embodiments, in addition to the first current equalization means relying on the primary capacitor to achieve the direct current flowing through the first secondary winding Ns1 and the direct current flowing through the second secondary winding Ns2 being approximately equal, a second current equalization means, i.e. adding a direct-current blocking capacitor (not shown) connected in series with the primary winding Np1, can also be used to achieve the direct current flowing through the first secondary winding Ns1 and the direct current flowing through the second secondary winding Ns2 being approximately equal. Furthermore, a third current equalization means, i.e. adding a current equalization circuit (not shown), can also be used to achieve the direct current flowing through the first secondary winding Ns1 and the direct current flowing through the second secondary winding Ns2 being approximately equal.The three current sharing methods can be used in the power conversion device.

[0121] In addition, in the embodiment, the AC magnetic flux of the first magnetic column 123 is large, but the air gap and the magnetic resistance are small, and the air gap and the magnetic resistance of the second magnetic column 124 relative to the first magnetic column 123 are large, but the AC magnetic flux of the second magnetic column 124 is small, so that the AC current ripple of the first secondary winding Ns1 is small, and the equivalent inductance of the first secondary winding Ns1 is large. Similarly, although the AC magnetic flux of the third magnetic column 125 is large, but the air gap and the magnetic resistance are small, and the air gap and the magnetic resistance of the fourth magnetic column 126 relative to the third magnetic column 125 are large, but the AC magnetic flux of the fourth magnetic column 126 is small, so that the AC current ripple of the second secondary winding Ns2 is small, and the equivalent inductance of the second secondary winding Ns2 is large. Correspondingly, the primary winding Np coupled with the first secondary winding Ns1 and the second secondary winding Ns2 also obtains the benefit of current ripple reduction, and the current ripple of the switching bridge arm flowing through the primary side switching circuit is also reduced, thereby reducing the switching loss. Therefore, the magnetic assembly of the present application has the advantages of small AC current ripple and strong current saturation resistance of the magnetic core.

[0122] In addition, for the structure of the magnetic core assembly 120, the materials of the entire magnetic core assembly 120 can be the same, such as ferrite material or iron powder material. In other embodiments, the materials of the first magnetic column 123 and the third magnetic column 125 or the materials of the second magnetic column 124 and the fourth magnetic column 126 are different from the materials of the remaining part of the magnetic core assembly 120, for example, the materials of the first magnetic column 123 and the third magnetic column 125 are ferrite material, the materials of the second magnetic column 124 and the fourth magnetic column 126 are distributed air gap iron powder material, and the materials of the first magnetic cover 121 and the second magnetic cover 122 can be ferrite material or iron powder material, thereby reducing the magnetic core loss of the magnetic core assembly 120 and increasing the equivalent inductance of the first secondary winding Ns1 and the second secondary winding Ns2. In some embodiments, the sum of the cross-sectional areas of the second magnetic column 124 and the fourth magnetic column 126 is greater than the sum of the cross-sectional areas of the first magnetic column 123 and the third magnetic column 125. Furthermore, the cross-sectional area of the second magnetic column 124 is approximately equal to the cross-sectional area of the fourth magnetic column 126, with an error within ±20%; the cross-sectional area of the first magnetic column 123 is approximately equal to the cross-sectional area of the third magnetic column 125, with an error within ±20%, wherein the error within ±20% means that the difference between the cross-sectional areas of the two magnetic columns is within ±20% of the cross-sectional area of one of the two magnetic columns.

[0123] Figure 21 The exploded structural diagram of the magnetic core assembly of the magnetic assembly of another preferred embodiment of the present application, Figure 22 The structural diagram of the magnetic assembly of another preferred embodiment of the present application when the first magnetic cover is removed. Figure 21 and Figure 22As shown, in this embodiment, the magnetic assembly 12 comprises a magnetic core assembly 120a, a primary winding Np, a first secondary winding Ns1 and a second secondary winding Ns2. The magnetic core assembly 120a comprises a first magnetic cover 121a, a second magnetic cover 122a, a first magnetic leg 123a, a second magnetic leg 124a and a third magnetic leg 125a. The first magnetic leg 123a, the second magnetic leg 124a and the third magnetic leg 125a are located between the first magnetic cover 121a and the second magnetic cover 122a, wherein the first magnetic leg 123a and the third magnetic leg 125a are oppositely arranged, and the second magnetic leg 124a is located between the first magnetic leg 123a and the third magnetic leg 125a. In some embodiments, the second magnetic leg 124a comprises an air gap, and the first magnetic leg 123a and the third magnetic leg 125a can not comprise an air gap, however, the disclosure is not limited thereto, in other embodiments, the first magnetic leg 123a and the third magnetic leg 125a can also comprise an air gap, but the length of the air gap of the second magnetic leg 124a is greater than the length of the air gap of the first magnetic leg 123a and the length of the air gap of the third magnetic leg 125a. Figure 22 In the magnetic core assembly 120a of FIG. 1, the first magnetic cover 121a is not shown, so that the changes in the number, position and winding mode of the magnetic legs can be clearly shown. In addition, Figure 22 In FIG. 1, diodes D1 and D2 represent the first rectifying assembly and the second rectifying assembly, respectively.

[0124] The first secondary winding Ns1 is wound between the first magnetic leg 123a and the second magnetic leg 124a, and the second secondary winding Ns2 is wound between the second magnetic leg 124a and the third magnetic leg 125a. The first rectifying assembly limits the current direction of the first secondary winding Ns1, and the second rectifying assembly limits the current direction of the second secondary winding Ns2, so that the current direction of the current flowing through the first secondary winding Ns1 and the current direction of the current flowing through the second secondary winding Ns2 are the same, both from the first end of the corresponding secondary winding to the second end of the corresponding secondary winding.

[0125] The first voltage across the first end and the second end of the first secondary winding Ns1 is 180 degrees out of phase with the second voltage across the first end and the second end of the second secondary winding Ns2. The alternating current magnetic flux generated by the first secondary winding Ns1 is applied to the first magnetic leg 123a, and the alternating current magnetic flux generated by the second secondary winding Ns2 is applied to the third magnetic leg 125a, and the alternating current magnetic flux generated by the first secondary winding Ns1 and the alternating current magnetic flux generated by the second secondary winding Ns2 are subtracted in phase and applied to the second magnetic leg 124a. In addition, the direct current component (hereinafter referred to as direct current) of the current flowing through the first secondary winding Ns1 and the direct current component (hereinafter referred to as direct current) of the current flowing through the second secondary winding Ns2 superimpose the direct current magnetic flux generated on the second magnetic leg 124a.

[0126] The primary winding Np of the magnetic core assembly 12 is wound on the first magnetic leg 123a and the third magnetic leg 125a in an alternating manner via the communication region in a ∞-shaped manner, such that the magnetic flux directions on the first magnetic leg 123a and the third magnetic leg 125a are opposite. Further, the primary winding Np is wound on the first magnetic leg 123a and the third magnetic leg 125a from the outside of the magnetic core assembly 12 (the first magnetic leg 123a) and the magnetic core assembly 12 (the third magnetic leg 125a) respectively.

[0127] In addition, the material of the entire magnetic core assembly 120a can be the same, such as ferrite material or iron powder material. In other embodiments, the material of the first magnetic leg 123a and the third magnetic leg 125a or the material of the second magnetic leg 124a is different from the material of the remaining part of the magnetic core assembly 120a. For example, the material of the first magnetic leg 123a and the third magnetic leg 125a is ferrite material, the material of the second magnetic leg 124a is iron powder material with distributed air gap, and the material of the first magnetic cover 121a and the second magnetic cover 122a can be ferrite material or iron powder material. In this way, the magnetic core loss of the magnetic core assembly 120a is low, and the equivalent inductance of the first secondary winding Ns1 and the second secondary winding Ns2 is large.

[0128] Any of the first capacitor, the second capacitor and the absorption capacitor disclosed in the present application can be realized by connecting a plurality of capacitors in parallel.

[0129] In summary, the present application provides a power conversion device, by externally disposing at least part of the capacitors outside the power module, to reduce the height of the power conversion device, while improving the power density of the power module.

[0130] It should be noted that the above merely describes the preferred embodiments of the present application, and the present application is not limited to the described embodiments, and the scope of the present application is determined by the appended claims. The present application can be modified by those skilled in the art without departing from the scope of the appended claims.

Claims

1. A power conversion device, comprising: a first capacitor and a second capacitor connected in series; and a power module electrically connected to the first capacitor and the second capacitor, and comprising a circuit board, an absorption capacitor, a primary side switching circuit, a magnetic assembly, and a secondary side circuit, wherein the absorption capacitor, the primary side switching circuit, the magnetic assembly, and the secondary side circuit are disposed on the circuit board, primary side windings and secondary side windings of the magnetic assembly are electrically connected to the primary side switching circuit and the secondary side circuit respectively, wherein the first capacitor and the second capacitor have capacitances greater than a capacitance of the absorption capacitor; wherein the first capacitor and the second capacitor are external to the power module.

2. The power conversion device of claim 1, further comprising a carrier board, wherein the first capacitor and the second capacitor and the power module are disposed on the carrier board, and the power module is electrically connected to the first capacitor and the second capacitor via the carrier board.

3. The power conversion device of claim 1, wherein the primary side switching circuit comprises two switches connected in series, and the two switches have a switching midpoint therebetween, the primary side switching circuit, the absorption capacitor, and the first capacitor and the second capacitor connected in series form a half-bridge circuit.

4. The power conversion device of claim 3, wherein the power module has a first end, a second end, and a third end, the primary side switching circuit is coupled between the first end and the third end and connected in parallel with the absorption capacitor, two ends of the primary side windings of the magnetic assembly are electrically connected to the switching midpoint and the second end respectively, a first end of the first capacitor and a first end of the second capacitor are electrically connected to a first capacitor midpoint, the first capacitor midpoint is electrically connected to the second end of the power module, a second end of the first capacitor is electrically connected to the first end of the power module, and a second end of the second capacitor is electrically connected to the third end of the power module.

5. The power conversion device of claim 4, wherein the absorption capacitor comprises a first absorption capacitor and a second absorption capacitor connected in series, and the first absorption capacitor and the second absorption capacitor have a second capacitor midpoint therebetween, the second capacitor midpoint is electrically connected to the second end of the power module.

6. The power conversion device of claim 4 or 5, wherein the power conversion device comprises a plurality of the power modules, a plurality of the first ends of the plurality of power modules are electrically connected to each other, a plurality of the second ends of the plurality of power modules are electrically connected to each other, and a plurality of the third ends of the plurality of power modules are electrically connected to each other.

7. The power conversion device of claim 1, wherein the secondary winding of the magnetic assembly has two first ends and a second end, the secondary circuit includes a first rectifying component and a second rectifying component, the first rectifying component is electrically connected between one of the first ends and a negative output terminal of the power conversion device, the second rectifying component is electrically connected between the other of the first ends and the negative output terminal, the second end is electrically connected to a positive output terminal of the power conversion device, and the first rectifying component and the second rectifying component each include at least one rectifying component.

8. The power conversion device of claim 7, wherein the secondary circuit further includes an output capacitor coupled between the positive output terminal and the negative output terminal.

9. The power conversion device of claim 1, wherein the magnetic assembly includes: at least one magnetic core assembly including: a first magnetic cover and a second magnetic cover; and a first magnetic leg, a second magnetic leg, a third magnetic leg, and a fourth magnetic leg, wherein the first magnetic leg and the third magnetic leg are oppositely disposed between the first magnetic cover and the second magnetic cover, the second magnetic leg and the fourth magnetic leg are oppositely disposed between the first magnetic cover and the second magnetic cover, the first magnetic leg and the third magnetic leg are located between the second magnetic leg and the fourth magnetic leg, the second magnetic leg and the fourth magnetic leg have a magnetic reluctance greater than the first magnetic leg and the third magnetic leg, respectively, and the first magnetic leg, the second magnetic leg, the third magnetic leg, and the fourth magnetic leg collectively define a communication region therebetween; a primary winding wound on the first magnetic leg and the third magnetic leg via the communication region, wherein the magnetic flux directions on the first magnetic leg and the third magnetic leg are opposite; and a first secondary winding and a second secondary winding, wherein a first end of the first secondary winding is threaded between the first magnetic leg and the second magnetic leg, a second end of the first secondary winding is threaded between the third magnetic leg and the fourth magnetic leg, a first end of the second secondary winding is threaded between the first magnetic leg and the fourth magnetic leg, a second end of the second secondary winding is threaded between the second magnetic leg and the third magnetic leg, and a portion of the first secondary winding and a portion of the second secondary winding are located within the communication region.

10. The power conversion device of claim 9, wherein the primary winding is wound on the first magnetic leg and the third magnetic leg via the communication region in an alternating manner presenting a ∞-shaped pattern.

11. The power conversion device of claim 9, wherein a length of an air gap of the second magnetic leg and a length of an air gap of the fourth magnetic leg are greater than a length of an air gap of the first magnetic leg and a length of an air gap of the third magnetic leg, respectively.

12. The power conversion device of claim 9, wherein the second magnetic leg and the fourth magnetic leg are made of a distributed air gap ferrite powder material, and the first magnetic leg and the third magnetic leg are made of a ferrite material.

13. The power conversion device of claim 1, wherein the magnetic assembly includes: at least one magnetic core assembly including: a first magnetic cover and a second magnetic cover; and a first magnetic leg, a second magnetic leg, a third magnetic leg, and a fourth magnetic leg, wherein the first magnetic leg and the third magnetic leg are oppositely disposed between the first magnetic cover and the second magnetic cover, the second magnetic leg and the fourth magnetic leg are oppositely disposed between the first magnetic cover and the second magnetic cover, the first magnetic leg and the third magnetic leg are located between the second magnetic leg and the fourth magnetic leg, the second magnetic leg and the fourth magnetic leg have a magnetic reluctance greater than the first magnetic leg and the third magnetic leg, respectively, and the first magnetic leg, the second magnetic leg, the third magnetic leg, and the fourth magnetic leg collectively define a communication region therebetween; a primary winding wound on the first magnetic leg and the third magnetic leg via the communication region, wherein the magnetic flux directions on the first magnetic leg and the third magnetic leg are opposite; and a first secondary winding and a second secondary winding, wherein a first end of the first secondary winding is threaded between the first magnetic leg and the second magnetic leg, a second end of the first secondary winding is threaded between the third magnetic leg and the fourth magnetic leg, a first end of the second secondary winding is threaded between the first magnetic leg and the fourth magnetic leg, a second end of the second secondary winding is threaded between the second magnetic leg and the third magnetic leg, and a portion of the first secondary winding and a portion of the second secondary winding are located within the communication region. ​ ​ ​ ​ ​ ​ a first magnetic cover and a second magnetic cover; and a first magnetic column, a second magnetic column and a third magnetic column disposed between the first magnetic cover and the second magnetic cover, wherein the second magnetic column is located between the first magnetic column and the third magnetic column; a primary winding wound on the first magnetic column and the third magnetic column; and a first secondary winding and a second secondary winding wound on the first magnetic column and the third magnetic column, respectively.

14. The power conversion device of claim 13, wherein the primary winding is wound on the first magnetic column and the third magnetic column in a manner presenting an ∞ shape.

15. The power conversion device of claim 13, wherein a length of an air gap of the second magnetic column is greater than a length of an air gap of the first magnetic column and a length of an air gap of the third magnetic column.

16. The power conversion device of claim 13, wherein a material constituting the second magnetic column is a distributed air gap iron powder material, and a material constituting the first magnetic column and the third magnetic column is a ferrite material.

17. A power conversion device, comprising: a first capacitor and a second capacitor connected in series; a primary side switching circuit connected in parallel with the first capacitor and the second capacitor; and a power module electrically connected to the first capacitor, the second capacitor and the primary side switching circuit, and comprising a circuit board, a magnetic assembly and a secondary side circuit, wherein the magnetic assembly and the secondary side circuit are disposed on the circuit board, and primary side windings and secondary side windings of the magnetic assembly are electrically connected to the primary side switching circuit and the secondary side circuit, respectively; wherein the first capacitor and the second capacitor are external to the power module.

18. The power conversion device of claim 17, further comprising a carrier board, wherein the first capacitor and the second capacitor, the primary side switching circuit and the power module are disposed on the carrier board, and the power module is electrically connected to the first capacitor, the second capacitor and the primary side switching circuit via the carrier board.

19. The power conversion device of claim 17, further comprising a carrier board and another circuit board, wherein the first capacitor and the second capacitor and the primary side switching circuit are disposed on the other circuit board, and the other circuit board and the power module are disposed on the carrier board.

20. The power conversion device of claim 17, wherein the primary side switching circuit comprises two switches connected in series, and the two switches have a switching midpoint therebetween, and the primary side switching circuit and the first capacitor and the second capacitor connected in series form a half-bridge circuit.

21. The power conversion device of claim 20, wherein the power module has a first end and a second end, two ends of the primary side windings of the magnetic assembly are electrically connected to the first end and the second end, respectively, a first end of the first capacitor and a first end of the second capacitor are electrically connected to a capacitor midpoint, and the switching midpoint and the capacitor midpoint are electrically connected to the first end and the second end of the power module, respectively.

22. The power conversion device of claim 21, wherein the power conversion device comprises a plurality of the power supply modules, a plurality of the first terminals of the plurality of power supply modules are electrically connected to each other, and a plurality of the second terminals of the plurality of power supply modules are electrically connected to each other.

23. The power conversion device of claim 17, wherein the secondary winding of the magnetic assembly has two first terminals and a second terminal, the secondary circuit comprises a first rectifying assembly and a second rectifying assembly, the first rectifying assembly is electrically connected between one of the first terminals and a negative output terminal of the power conversion device, the second rectifying assembly is electrically connected between the other of the first terminals and the negative output terminal, the second terminal is electrically connected to a positive output terminal of the power conversion device, and the first rectifying assembly and the second rectifying assembly each comprises at least one rectifying assembly.

24. The power conversion device of claim 23, wherein the secondary circuit further comprises an output capacitor coupled between the positive output terminal and the negative output terminal.

25. The power conversion device of claim 17, wherein the magnetic assembly comprises: at least one magnetic core assembly comprising: a first magnetic cover and a second magnetic cover; and a first magnetic leg, a second magnetic leg, a third magnetic leg, and a fourth magnetic leg, wherein the first magnetic leg and the third magnetic leg are oppositely disposed between the first magnetic cover and the second magnetic cover, the second magnetic leg and the fourth magnetic leg are oppositely disposed between the first magnetic cover and the second magnetic cover, the first magnetic leg and the third magnetic leg are located between the second magnetic leg and the fourth magnetic leg, the second magnetic leg and the fourth magnetic leg have a larger magnetic reluctance than the first magnetic leg and the third magnetic leg, respectively, and the first magnetic leg, the second magnetic leg, the third magnetic leg, and the fourth magnetic leg collectively define a communication region therebetween; a primary winding wound on the first magnetic leg and the third magnetic leg via the communication region, wherein the magnetic flux directions on the first magnetic leg and the third magnetic leg are opposite; and a first secondary winding and a second secondary winding, wherein a first terminal of the first secondary winding is threaded between the first magnetic leg and the second magnetic leg, a second terminal of the first secondary winding is threaded between the third magnetic leg and the fourth magnetic leg, a first terminal of the second secondary winding is threaded between the first magnetic leg and the fourth magnetic leg, a second terminal of the second secondary winding is threaded between the second magnetic leg and the third magnetic leg, and a portion of the first secondary winding and a portion of the second secondary winding are located within the communication region.

26. The power conversion device of claim 25, wherein the primary winding is wound on the first magnetic leg and the third magnetic leg via the communication region in an alternating manner presenting a ∞-shaped pattern.

27. The power conversion device of claim 25, wherein a length of an air gap of the second magnetic leg and a length of an air gap of the fourth magnetic leg are greater than a length of an air gap of the first magnetic leg and a length of an air gap of the third magnetic leg, respectively. ​ ​ ​ ​ ​ 28. The power conversion device of claim 25, wherein the second magnetic leg and the fourth magnetic leg are made of a distributed air gap ferrite powder material, and the first magnetic leg and the third magnetic leg are made of a ferrite material.

29. The power conversion device of claim 17, wherein the magnetic assembly comprises: at least one magnetic core assembly comprising: a first magnetic leg, a second magnetic leg, and a third magnetic leg disposed between the first magnetic leg and the second magnetic leg, wherein the second magnetic leg is positioned between the first magnetic leg and the third magnetic leg; a primary winding wound around the first magnetic leg and the third magnetic leg; and a first secondary winding and a second secondary winding wound around the first magnetic leg and the third magnetic leg, respectively.

30. The power conversion device of claim 29, wherein the primary winding is wound around the first magnetic leg and the third magnetic leg in a shape that presents an ∞.

31. The power conversion device of claim 29, wherein a length of an air gap of the second magnetic leg is greater than a length of an air gap of the first magnetic leg and a length of an air gap of the third magnetic leg.

32. The power conversion device of claim 29, wherein the second magnetic leg is made of a distributed air gap ferrite powder material, and the first magnetic leg and the third magnetic leg are made of a ferrite material. ​ ​ ​ ​ ​

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