Single-stage AC / DC resonant converter

Abstract

A single-stage AC / DC resonant converter is used for converting a three-phase AC power supply into a DC power supply. The single-stage AC / DC resonant converter comprises a primary side circuit, a resonant circuit and a secondary side circuit. The primary side circuit comprises three groups of primary side switching circuits, and the primary side switching circuits are respectively coupled with one phase of alternating current power supply of the three-phase alternating current power supply. The resonant circuit comprises three groups of transformers, primary side windings of the transformers are respectively coupled with the primary side switching circuits, and secondary side windings of the transformers are coupled with the secondary side circuits.

Description

TECHNICAL FIELD

[0001] The present application relates to a single-stage AC / DC resonant converter. BACKGROUND

[0002] Due to the power supply or battery charging requirements of various electronic devices, AC / DC converters have been indispensable power conversion devices. Conventional AC / DC converters, as shown in FIG. 1, are usually of a two-stage circuit structure. Specifically, the conventional AC / DC converter 100A includes an AC / DC conversion circuit 100B, an intermediate capacitor CI, and a DC / DC conversion circuit 100C. The AC / DC conversion circuit 100B converts a single-phase or three-phase AC power supply into an intermediate power supply and stores the intermediate power supply in the intermediate capacitor CI. The DC / DC conversion circuit 100C takes the intermediate power supply stored in the intermediate capacitor CI as an input source and converts it into an output power supply of a specific voltage level to supply power (or charge) to a load 200 coupled to the back end. Figure 1

[0003] On the other hand, if the input power supply of the AC / DC converter 100A is a three-phase AC power supply, a complete set of conversion circuits must usually be used for power conversion for each phase. Therefore, most three-phase AC / DC converters 100A include three sets of AC / DC conversion circuits 100B, intermediate capacitors CI, and DC / DC conversion circuits 100C. Since the intermediate capacitor CI is generally mainly used to store a large amount of power and needs to occupy a large configuration space, the volume of the AC / DC converter 100A is too large and is not conducive to miniaturization design.

[0004] Therefore, how to design a single-stage AC / DC resonant converter using a single-stage circuit structure to replace the conventional two-stage circuit structure is a major issue that the present inventor desires to research. SUMMARY

[0005] To solve the above problems, the present disclosure provides a single-stage AC / DC resonant converter to overcome the problems of the prior art. Therefore, the single-stage AC / DC resonant converter of the present disclosure is used to convert a three-phase AC power supply into a DC power supply, and the single-stage AC / DC resonant converter includes a primary side circuit, a resonant circuit, and a secondary side circuit. The primary side circuit includes three sets of primary side switching circuits, the primary side switching circuits are respectively coupled to one of the three-phase AC power supplies, and the primary side switching circuits respectively include a rectification circuit and a switching circuit. The rectification circuit includes a rectification bridge arm and a capacitor in parallel with the rectification bridge arm, and the switching circuit is coupled to the capacitor. The resonant circuit includes three sets of transformers, the primary side windings of the transformers are respectively coupled to the switching circuits of the primary side switching circuits, and the secondary side windings of the transformers form a secondary side common connection winding. The secondary side circuit includes a set of secondary side switching circuits, and the secondary side switching circuits are coupled to the secondary side common connection winding.​

[0006] To solve the above problems, the present disclosure provides a single-stage AC-DC resonant converter to overcome the problems of the prior art. Therefore, the single-stage AC-DC resonant converter of the present disclosure is used to convert a three-phase AC power supply into a DC power supply, and the single-stage AC-DC resonant converter includes a primary side circuit, a resonant circuit and a secondary side circuit. The primary side circuit includes three groups of primary side switching circuits, and each of the primary side switching circuits includes a filter circuit and a switching circuit. The filter circuit is coupled to one of the three-phase AC power supply, and the switching circuit is coupled to the filter circuit. The resonant circuit includes three groups of transformers, the primary side windings of the transformers are coupled to the switching circuits of the primary side switching circuits, and the secondary side windings of the transformers form a secondary side common connection winding. The secondary side circuit includes a group of secondary side switching circuits, and the secondary side switching circuits are coupled to the secondary side common connection winding.

[0007] To solve the above problems, the present disclosure provides a single-stage AC-DC resonant converter to overcome the problems of the prior art. Therefore, the single-stage AC-DC resonant converter of the present disclosure is used to convert a three-phase AC power supply into a DC power supply, and the single-stage AC-DC resonant converter includes a primary side circuit, a resonant circuit and a secondary side circuit. The primary side circuit includes three groups of primary side switching circuits, and each of the primary side switching circuits includes a filter circuit and a switching circuit. The filter circuit is coupled to one of the three-phase AC power supply, and the switching circuit is coupled to the filter circuit. The resonant circuit includes three groups of transformers, the primary side windings of the transformers are coupled to the switching circuits of the primary side switching circuits, and the secondary side windings of the transformers form a secondary side common connection winding. The secondary side circuit includes a group of secondary side switching circuits, and the secondary side switching circuits are coupled to the secondary side common connection winding.

[0008] The main purpose and effect of the present disclosure is that, due to the single-stage AC-DC resonant converter of the present disclosure, the single-stage circuit structure is used to replace the conventional two-stage circuit structure, and the three-phase input is converted into an output power supply by using multiple switches for switching. Therefore, the single-stage AC-DC resonant converter of the present disclosure does not need an intermediate energy storage element.

[0009] In order to further understand the technology, means and effects taken by the present application to achieve the predetermined purpose, please refer to the following detailed description and drawings of the present application. It is believed that the purpose, features and characteristics of the present application can be deeply and specifically understood from the drawings. However, the attached drawings are provided for reference and explanation only, and are not intended to limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 for the existing two-stage AC-DC converter;

[0011] Figure 2 for the circuit diagram of the first embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0012] Figure 3 Circuit diagram for a second embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0013] Figure 4 Circuit diagram for a third embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0014] Figure 5 Circuit diagram for a fourth embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0015] Figure 6 Circuit diagram for a fifth embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0016] Figure 7 Circuit diagram for a sixth embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0017] Figure 8 Circuit diagram for a seventh embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0018] Figure 9 Circuit diagram for an eighth embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0019] Figure 10 Circuit diagram for a ninth embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0020] Figure 11 Circuit diagram for a tenth embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0021] Figure 12 Circuit diagram for an eleventh embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0022] Figure 13 Circuit diagram for a twelfth embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0023] Figure 14 Circuit diagram for a thirteenth embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0024] Figure 15 Circuit diagram for a fourteenth embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0025] Figure 16 Circuit diagram for a fifteenth embodiment of the single-stage AC-DC resonant converter of the present disclosure;

[0026] Figure 17 Circuit diagram for a sixteenth embodiment of the single-stage AC-DC resonant converter of the present disclosure; and

[0027] Figure 18 This is a circuit diagram of the seventeenth embodiment of the single-stage AC / DC resonant converter of this disclosure.

[0028] Explanation of reference numerals in the attached figures

[0029] 100A: AC / DC converter

[0030] 100B: AC / DC conversion circuit

[0031] CI: Intermediate capacitor

[0032] 100C: DC / DC converter circuit

[0033] 100: Resonant Converter

[0034] A: Primary side circuit

[0035] 1: Primary-side switching circuit

[0036] 2: Rectifier circuit

[0037] L: Inductance

[0038] Cf: Capacitor

[0039] 22: Rectifier bridge arm

[0040] 222: First rectifier bridge arm

[0041] Qr1: First rectifier switch

[0042] Qr2: Second rectifier switch

[0043] 224: Second rectifier bridge arm

[0044] Qr3: Third rectifier switch

[0045] Qr4: Fourth rectifier switch

[0046] 3: Filtering circuit

[0047] 4: Switching circuit

[0048] L1: First Inductor

[0049] L2: Second Inductor

[0050] 42: First switching bridge arm

[0051] Q1: First switching switch

[0052] Q2: Second switch

[0053] 422: First switch module

[0054] 424: Second Switch Module

[0055] 44: second switching leg

[0056] Q3: third switching switch

[0057] Q4: fourth switching switch

[0058] 442: third switch module

[0059] 444: fourth switch module

[0060] Pgnd1, Pgnd2, Pgnd3: primary side ground terminal

[0061] B: resonance circuit

[0062] Lr1, Lr2: resonance inductor

[0063] Cr1, Cr2: resonance capacitor

[0064] T: transformer

[0065] Wp: primary side winding

[0066] Wp1: first primary side winding

[0067] Wp2: second primary side winding

[0068] Pc: center tap terminal

[0069] Ws: secondary side winding

[0070] WCs: secondary side common connection winding

[0071] C: secondary side circuit

[0072] 5: secondary side switching circuit

[0073] 52: first secondary side leg

[0074] Qs1: first secondary side switch

[0075] Qs2: second secondary side switch

[0076] 54: second secondary side leg

[0077] Qs3: third secondary side switch

[0078] Qs4: fourth secondary side switch

[0079] 56: third secondary side leg

[0080] Qs5: fifth secondary side switch

[0081] Qs6: sixth secondary side switch

[0082] Co: output capacitor

[0083] Sgnd: secondary side ground terminal

[0084] P: node

[0085] P1: first node

[0086] P2: second node

[0087] P3: third node

[0088] Pr1: first rectification node

[0089] Pr2: second rectification node

[0090] Pp1: first primary side node

[0091] Pp2: second primary side node

[0092] Pp3: third primary side node

[0093] Ps1: first secondary side node

[0094] Ps2: second secondary side node

[0095] Ps3: third secondary side node

[0096] 6: controller

[0097] 200: load

[0098] R, Y, B: three-phase AC power source

[0099] Pac: AC power source

[0100] N: neutral terminal

[0101] Pdc: DC power source

[0102] Sc: control signal DETAILED DESCRIPTION

[0103] The technical contents and detailed descriptions of the present application are described as follows in conjunction with the accompanying drawings:

[0104] The single-stage AC-DC resonant converter of the present disclosure is different from Figure 1The existing two-stage AC / DC converter needs an intermediate energy storage element to store energy as a DC power supply, and then converts the DC power supply to an output power supply. Specifically, the single-stage AC / DC resonant converter of the present disclosure is applicable to an unfolded topology for three-phase / single-phase, mainly for the topology application of matrix converters. The matrix converter converts three-phase input to output power supply mainly by using multiple switches for switching. Among them, the matrix converter, like a voltage source and current source frequency converter, will be divided into several stages to process voltage and current conversion, but the DC link has no intermediate energy storage element, so voltage and current conversion can be completed in a single-stage converter. Therefore, the capacitor between the three-phase AC power supply R, Y, B and the output capacitor Co is mainly not used for energy storage, but for filtering. Therefore, the single-stage AC / DC resonant converter can process three-phase AC power supply R, Y, B in a phase-by-phase manner.

[0105] Please refer to Figure 2 The circuit diagram of the first embodiment of the single-stage AC / DC resonant converter of the present disclosure is shown in FIG. 1, and please refer to Figure 1 The single-stage AC / DC resonant converter 100 can use a circuit architecture composed of inductance and capacitance resonant tank (such as but not limited to LC, C LLC, etc.), especially particularly suitable for using dual active bridge (DAB) and series resonant dual active bridge (SR DAB) circuit architecture. That is, the single-stage AC / DC resonant converter 100 of the present disclosure can process three-phase AC power supply R, Y, B in a phase-by-phase manner to convert to a DC power supply Pdc, and the voltage level of the converted DC power supply Pdc can be set by the controller 6 to be adjusted up or down. On the other hand, in order to avoid the circuit structure being too messy, the circuit architecture of the series resonant dual active bridge (SR DAB) is mainly described in the present disclosure, and other circuit architectures can be inferred from the circuit structure shown in the present disclosure, and are not described in detail.

[0106] Please refer to Figure 2, a single-stage AC / DC resonant converter (hereinafter referred to as resonant converter 100) is used to convert a three-phase AC power source R, Y, B into a DC power source Pdc, and the resonant converter 100 includes a primary side circuit A, a resonant circuit B, and a secondary side circuit C. The primary side circuit A includes three sets of primary side switching circuits 1, and each set of primary side switching circuits 1 includes a rectification circuit 2 and a switching circuit 4, respectively. The rectification circuit 2 includes a rectification bridge arm 22 and a capacitor Cf connected in parallel with the rectification bridge arm 22, and the switching circuit 4 is coupled to the capacitor Cf. The capacitor Cf is not an intermediate energy storage element (i.e., not an electrolytic capacitor or the like that can be used to store a large amount of power) as previously described, and thus is not primarily used for energy storage, but rather for filtering.

[0107] The resonant circuit B mainly includes three sets of resonant tanks and three sets of transformers T, and the resonant tanks can be different depending on the circuit architecture of the resonant converter 100. Among them, the circuit architecture of the SR DAB is mainly explained as the object of the present disclosure, that is, the resonant tank includes a primary side resonant tank and a secondary side resonant tank. The primary side resonant tank includes a resonant inductor Lr1 and a resonant capacitor Cr1 connected in series, and the secondary side resonant tank includes a resonant inductor Lr2 and a resonant capacitor Cr2 connected in series. Each transformer T includes a primary side winding Wp and a secondary side winding Ws, and the primary side winding Wp is coupled to the switching circuit 4 of the primary side switching circuit 1 through the primary side resonant tank, respectively. When the circuit architecture of the resonant converter 100 is the circuit architecture of the SR DAB, the secondary side winding Ws and the secondary side resonant tank form a secondary side common connection winding WCs, and when the circuit architecture of the resonant converter 100 does not have a secondary side resonant tank, the secondary side winding Ws forms a secondary side common connection winding WCs. It is worth mentioning that in an embodiment, the turns ratio of the primary side winding Wp and the secondary side winding Ws is shown as n:1, but it is not limited thereto, and it can be any ratio that can be implemented in the resonant converter 100.

[0108] The secondary side circuit C is different from the primary side circuit A, and it only includes a set of secondary side switching circuits 5, and the secondary side switching circuits 5 are coupled to the secondary side common connection winding WCs and the load 200. Among them, the load 200 can be a battery, especially a battery for electric vehicles, but it is not limited thereto. The resonant converter 100 further includes a controller 6, and the controller provides a control signal Sc to control the primary side circuit A and the secondary side circuit C to divide the three-phase AC power source R, Y, B into several stages to process the conversion of voltage and current to convert it into a DC power source Pdc.

[0109] Further, in combination with the above Figure 2The rectifier circuit 2 comprises an inductor L in addition to the rectifier bridge arms 22 and the parallel capacitors Cf, and the inductor L is also used for filtering. The inductor L of each set of primary side switching circuit 1 is coupled to one of the three-phase AC power supply R, Y, B, and the rectifier bridge arms 22 comprise a first rectifier bridge arm 222 and a second rectifier bridge arm 224 in parallel with the capacitors Cf. One of the first rectifier bridge arms 222 is coupled to the inductor L, and the other of the first rectifier bridge arms 222 is coupled to the other end of the AC power supply Pac.

[0110] Specifically, the inductor L is coupled to the first rectifier bridge arm 222. The first rectifier bridge arm 222 can comprise a first rectifier switch Qr1 and a second rectifier switch Qr2 in series, and a first rectification node Pr1 is formed between the first rectifier switch Qr1 and the second rectifier switch Qr2. The second rectifier bridge arm 224 can also comprise a third rectifier switch Qr3 and a fourth rectifier switch Qr4 in series, and a second rectification node Pr2 is formed between the third rectifier switch Qr3 and the fourth rectifier switch Qr4. Thus, the other end of the inductor L is coupled to the first rectification node Pr1, and the second rectification node Pr2 is coupled to the neutral terminal N of the three-phase AC power supply R, Y, B.

[0111] The switching circuit 4 comprises a first switching bridge arm 42 and a second switching bridge arm 44 in parallel with the capacitors Cf. The first switching bridge arm 42 can comprise a first switching switch Q1 and a second switching switch Q2 in series, and a first primary side node Pp1 is formed between the first switching switch Q1 and the second switching switch Q2. The second switching bridge arm 44 can comprise a third switching switch Q3 and a fourth switching switch Q4 in series, and a second primary side node Pp2 is formed between the third switching switch Q3 and the fourth switching switch Q4. One of the first primary side node Pp1 and the second primary side node Pp2 is coupled to the primary side ground terminal Pgnd1, Pgnd2, Pgnd3 (hereinafter referred to as the first primary side node Pp1), and the other of the first primary side node Pp1 and the second primary side node Pp2 is coupled to the primary side winding Wp of the transformer T. The coupled primary side ground terminals Pgnd1, Pgnd2, Pgnd3 of each set of primary side switching circuit 1 are different, so each first primary side node Pp1 is coupled to a different primary side ground terminal Pgnd1, Pgnd2, Pgnd3. The same applies to the coupling relationship of each embodiment described below, which will not be described again.

[0112] Since one end of the primary winding Wp is also coupled to the primary-side ground terminals Pgnd1, Pgnd2, and Pgnd3, the two ends of the primary winding Wp are respectively coupled to the first primary-side node Pp1 and the second primary-side node Pp2. Furthermore, the resonant inductance Lr1 and resonant capacitor Cr1 of the primary-side resonant slot can be coupled between the first primary-side node Pp1 and one end of the primary winding Wp. Figure 2 (This structure is illustrated here), or it can be coupled between the primary winding Wp and the primary ground terminals Pgnd1, Pgnd2, and Pgnd3. In addition, there are many other structures for the primary resonant slot (such as, but not limited to, a single resonant inductor) and feasible coupling methods (such as, but not limited to, the resonant inductor Lr1 and the resonant capacitor Cr1 being respectively configured on both sides of the primary winding Wp), which will not be described in detail here.

[0113] exist Figure 2 On the secondary side, the secondary windings Ws are coupled to the primary windings Wp, and are connected to the same node to form a structure of a secondary common winding WCs. Specifically, the first end of each secondary winding Ws is coupled to the secondary ground terminal Sgnd, and the second end of each secondary winding Ws is coupled to a node P. The secondary-side switching circuit 5 includes a primary-side bridge arm 52, a secondary-side bridge arm 54, and an output capacitor Co, and the primary-side bridge arm 52 and the secondary-side bridge arm 54 are connected in parallel with the output capacitor Co. Furthermore, the load 200 can receive DC power Pdc by coupling to the output capacitor Co. The primary-side bridge arm 52 includes a primary-side switch Qs1 and a secondary-side switch Qs2 connected in series, and the primary-side switch Qs1 and the secondary-side switch Qs2 form a primary-side node Ps1. The second-stage side bridge arm 54 includes a third-stage side switch Qs3 and a fourth-stage side switch Qs4 connected in series, and a second-stage side node Ps2 is formed between the third-stage side switch Qs3 and the fourth-stage side switch Qs4.

[0114] Node P of the secondary winding Ws is coupled to one of the primary winding nodes Ps1 and Ps2 (illustrated here as primary winding node Ps1), and the other of primary winding node Ps1 and Ps2 is coupled to the secondary ground terminal Sgnd. Since one end of the secondary winding Ws is also coupled to the secondary ground terminal Sgnd, the two ends of the secondary winding Ws are coupled to primary winding node Ps1 and secondary winding node Ps2, respectively. Furthermore, the resonant inductance Lr2 and resonant capacitor Cr2 of the secondary resonant slot can be configured similarly to those of the primary resonant slot, and will not be elaborated further here.

[0115] In summary, the controller 6 provides the control signal Sc to the rectifier bridge arm 22 of the resonant converter 100, so that the rectifier bridge arm 22 can perform full-wave rectification, and the rectified power is then converted into a specific level of DC power Pdc through the switching circuit 4, the resonant circuit B and the secondary side circuit C. Moreover, the resonant converter 100 can also provide the function of power factor correction (PFC) through the setting and operation of the controller 6, so as to improve the power conversion efficiency of the resonant converter 100. It is worth mentioning that in an embodiment, the rectifier bridge arm 22 mainly performs rectification on the AC power Pac, so the switching speed of the switches inside the controller 6 (for example, but not limited to, the mains frequency) is slower than the switching speed of the switches inside the switching circuit 4 (for example, but not limited to, 400 kHz ~ 600 kHz). Therefore, the rectifier bridge arm 22 can also be called a slow arm, and the switching bridge arms 42, 44 inside the switching circuit 4 can be called fast arms. The subsequent disclosure is the same, and will not be repeated here.

[0116] In addition, in the resonant converter 100 of the present disclosure, Figure 2 the secondary side windings Ws of the transformer T are directly connected in parallel and commonly coupled to the same node P, and a single set of secondary side switching circuit 5 is coupled through the node P. Therefore, the number of secondary side switches can be reduced (at least 8 switches can be reduced if compared with a three-set conversion architecture), thereby reducing the power loss of the switches and reducing the number of control signal outputs of the controller 6. On the other hand, the switches in the present disclosure are shown as MOSFETs, but are not limited thereto. Any electronic element that can be used as a switch should be included in the scope of the present embodiment (for example, but not limited to, insulated gate bipolar transistors, gallium nitride transistors, etc.).

[0117] Please refer to Figure 3 the circuit diagram of the second embodiment of the single-stage AC / DC resonant converter of the present disclosure, and Figure 2 . Figure 3 the primary side circuit A is exactly the same as Figure 2 , and the structure and coupling method of the primary side winding Wp of the transformer T are also the same as Figure 2 . The difference between the two is that Figure 3 the structure of the secondary side common connection winding WC and the secondary side circuit C is different from Figure 2 . Specifically, Figure 3 the secondary side winding Ws has a delta connection structure. Therefore, the secondary side winding Ws is sequentially coupled end-to-end to form a first node P1, a second node P2 and a third node P3.

[0118] The secondary side switching circuit 5 includes Figure 2The first secondary side bridge leg 52 and the second secondary side bridge leg 54 further include a third secondary side bridge leg 56. The third secondary side bridge leg 56 is parallel to the first secondary side bridge leg 52, and the third secondary side bridge leg 56 includes a fifth secondary side switch Qs5 and a sixth secondary side switch Qs6 connected in series. A third secondary side node Ps3 is formed between the fifth secondary side switch Qs5 and the sixth secondary side switch Qs6, and the first node P1, the second node P2 and the third node P3 are coupled to the first secondary side node Ps1, the second secondary side node Ps2 and the third secondary side node Ps3, respectively. By means of the delta connection structure of the three-phase transformer T, the number of secondary side switches can be reduced. Figure 3 Moreover, since the secondary side winding Ws is wound as a three-phase winding and can be wrapped by a single core to form a three-phase transformer, the size of the three-phase transformer can be reduced (compared to using three transformers in a conventional converter).

[0119] Please refer to Figure 4 for the circuit diagram of the third embodiment of the single-stage AC / DC resonant converter of the present disclosure, and please refer to Figures 2-3 . Figure 4 The primary side circuit A and Figure 2 the structure and the coupling manner of the primary side winding Wp of the transformer T are also the same as Figure 2 , and the structure of the secondary side circuit C is the same as Figure 3 . Figure 4 The difference between Figures 2-3 lies in that the structure of the secondary side common connection winding WC and the secondary side circuit C is different from Figures 2-3 . Specifically, Figure 4 the secondary side winding Ws is a delta connection structure. Therefore, the first end of each secondary side winding is coupled to the first secondary side node Ps1, the second secondary side node Ps2 and the third secondary side node Ps3 of the switching circuit 5, respectively, and the second end of each secondary side winding Ws is similarly coupled to a single node P. Therefore, Figure 2 the effect brought by the circuit architecture of Figure 4 is similar to Figure 3 , which can also reduce the number of secondary side switches, and can also reduce the size of the three-phase transformer.

[0120] Please refer to Figure 5 for the circuit diagram of the fourth embodiment of the single-stage AC / DC resonant converter of the present disclosure, and please refer to Figures 2-4 . Figure 5 The rectifier circuit 2 and Figure 2 are exactly the same, and the difference lies in that the secondary side circuit C includes three groups of secondary side switching circuits 5, and the circuit architecture of the switching circuit 4 is also different from Figure 2They are not the same. Specifically, the switching circuit 4 includes a first switching switch Q1 and a second switching switch Q2. One end of the first switching switch Q1 and the second switching switch Q2 is coupled to one end of the capacitor Cf, and the other end of the capacitor Cf is coupled to the primary side ground terminals Pgnd1, Pgnd2, and Pgnd3.

[0121] On the other hand, the circuit architecture of resonant circuit B is also similar to... Figure 2 They are not the same. Furthermore, Figure 5 The resonant circuit B is shown in the diagram without a primary-side resonant slot, and the secondary side includes a secondary-side resonant slot formed by the resonant inductor Lr2 and the resonant capacitor Cr2. Specifically, the primary winding Wp of each transformer T includes a first primary winding Wp1 and a second primary winding Wp2 connected in series, and a center tap Pc is formed between the first primary winding Wp1 and the second primary winding Wp2. One end of the first primary winding Wp1 is coupled to the other end of the first switching switch Q1, one end of the second primary winding Wp2 is coupled to the other end of the second switching switch Q2, and the center tap Pc of the transformer T is coupled to the primary-side ground terminals Pgnd1, Pgnd2, and Pgnd3.

[0122] exist Figure 5 In the middle, the circuit architecture of the three sets of secondary-side switching circuits 5 are all the same as Figure 2 Similarly, the input terminal of the secondary-side switching circuit 5 is coupled to the secondary-side winding Ws of the transformer T. Specifically, one of the first-side node Ps1 and the second-side node Ps2 of each set of secondary-side switching circuits 5 (here, the first-side node Ps1 is used as an example) is coupled to one end of each set of secondary-side windings Ws, and the other of the first-side node Ps1 and the second-side node Ps2 of each set of secondary-side switching circuits 5 is coupled to the secondary-side ground terminal Sgnd. Since one end of the secondary-side winding Ws is also coupled to the secondary-side ground terminal Sgnd, the two ends of the secondary-side winding Ws are coupled to the first-side node Ps1 and the second-side node Ps2, respectively. Furthermore, the resonant inductance Lr2 and the resonant capacitance Cr2 of the secondary-side resonant slot can be similar to... Figure 2 The configuration of the secondary side resonant slot will not be elaborated here.

[0123] See also Figure 5 The three sets of secondary-side switching circuits 5 are independent of each other, and their output terminals are connected in parallel to jointly power the load 200. Specifically, one end of the output capacitor Co of the three sets of secondary-side switching circuits 5 is jointly coupled to form a positive output terminal, and the other end of the output capacitor Co is jointly coupled to form a negative output terminal. The positive and negative output terminals can be coupled to the load 200 to power it. In summary, because Figure 5The switching circuit 4 of each phase uses only two switches (i.e. the first switching switch Q1 and the second switching switch Q2), so it can reduce the number of switches of the primary side switching circuit 1.

[0124] Please refer to Figure 6 The circuit diagram of the fifth embodiment of the single-stage AC / DC resonant converter of the present disclosure is shown in FIG. 9, and please refer to Figures 2-5 , and refer to Figure 3 , Figure 5 . Figure 6 The circuit architecture is a combination of the partial circuit architectures of Figure 2 , Figure 5 , and the corresponding effects described above can be achieved. Specifically, Figure 6 The primary side circuit A of Figure 5 , and Figure 6 The secondary side circuit C of Figure 2 . Moreover, Figure 6 The circuit structure of the primary side winding Wp is the same as Figure 5 , which is also a center-tapped structure. The secondary side winding Ws is the same as Figure 2 , which is a structure connected to the same node P. The remaining detailed circuit structures and features can be referred to Figure 3 , Figure 5 , which will not be described here.

[0125] Please refer to Figure 7 The circuit diagram of the sixth embodiment of the single-stage AC / DC resonant converter of the present disclosure is shown in FIG. 10, and please refer to Figures 2-6 , and refer to Figure 3 , Figure 5 . Figure 7 Similar to Figure 6 , the circuit architecture is a combination of the partial circuit architectures of Figure 3 , Figure 5 , and the corresponding effects described above can be achieved. Mainly, the secondary side winding Ws is the same as Figure 3 , which is a delta connection structure. The remaining detailed circuit structures and features can be referred to Figure 3 , Figure 5 , which will not be described here.

[0126] Please refer to Figure 8 The circuit diagram of the seventh embodiment of the single-stage AC / DC resonant converter of the present disclosure is shown in FIG. 11, and please refer to Figures 2-7 , and refer to Figures 4-5 . Figure 8 Also similar to Figure 6 , the circuit architecture is a combination of the partial circuit architectures of Figure 4 , Figure 5 , and the corresponding effects described above can be achieved. Mainly, the secondary side winding Ws is the same as Figure 4Y-shaped connection structure. The rest of the detailed circuit structure and features can be combined with reference to Figure 4 、 Figure 5 , which will not be repeated here.

[0127] Please refer to Figure 9 is the circuit diagram of the eighth embodiment of the single-stage AC-DC resonant converter of the present disclosure, and is combined with reference to Figures 2-8 . Figure 9 The main feature of Figure 9 is that the fast arm and the slow arm in the primary side circuit A are integrated together to form a circuit with three sets of bridge arms in parallel. Specifically, Figure 2 The switching circuit 4 includes a first switching bridge arm 42 and a second switching bridge arm 44, and further includes a rectifier bridge arm 22 in parallel to form a circuit with three sets of bridge arms in parallel. Further, the rectifier bridge arm 22 is connected in parallel to a capacitor Cf, and the rectifier bridge arm 22 includes a first rectifier switch Qr1 and a second rectifier switch Qr2 connected in series, and a third primary side node Pp3 is formed between the first rectifier switch Qr1 and the second rectifier switch Qr2. One end of the first rectifier switch Qr1 is connected to one end of the capacitor Cf, one end of the second rectifier switch Qr2 is connected to the other end of the first rectifier switch Qr1 to form the third primary side node Pp3, and the other end of the second rectifier switch Qr2 is connected to the other end of the capacitor Cf.

[0128] In addition, the switching circuit 4 further includes a first inductor L1 and a second inductor L2. One end of the first inductor L1 is connected to one end of the AC power source Pac, and the other end of the first inductor L1 is connected to the first primary side node Pp1. One end of the second inductor L2 is connected to one end of the AC power source Pac, and the other end of the second inductor L2 is connected to the second primary side node Pp2. As Figure 2 the same, one of the first primary side node Pp1 and the second primary side node Pp2 is connected to the primary side winding Wp, and the other is connected to the primary side ground Pgnd1, Pgnd2, Pgnd3. Moreover, the third primary side node Pp3 is connected to the other end of the AC power source Pac. Among them, Figure 9 The circuit structure of Figure 2 is based on the structure of a boost converter circuit, which is similar to a totem pole power factor corrector. That is, the primary side circuit A can mainly boost the AC power source Pac, and it also reduces one set of slow bridge arms. In addition, the rest of the circuit structure and functions are similar to , which will not be repeated here.

[0129] Please refer to Figure 10 is the circuit diagram of the ninth embodiment of the single-stage AC-DC resonant converter of the present disclosure, and is combined with reference to Figures 2-9 , and repeatedly combined with reference to Figure 3 、 Figure 9 . Figure 10 The circuit architecture of Figure 3 ,Figure 9 This is a combination of some circuit architectures, which can achieve the corresponding effects described above. Mainly, the secondary winding Ws is like... Figure 3 It uses a delta-connected structure. For further details on the circuit structure and features, please refer to [reference needed]. Figure 3 , Figure 9 This will not be elaborated upon further here.

[0130] Please see Figure 11 This is a circuit diagram of the tenth embodiment of the single-stage AC / DC resonant converter disclosed herein, with reference to other relevant documents. Figures 2-10 And consulted repeatedly Figure 4 , Figure 9 . Figure 11 The circuit architecture is mainly for Figure 4 , Figure 9 This is a combination of some circuit architectures, which can achieve the corresponding effects described above. Mainly, the secondary winding Ws is like... Figure 4 It features a Y-shaped wiring structure. Further details regarding the circuit structure and its characteristics can be found in the reference book. Figure 4 , Figure 9 This will not be elaborated upon further here.

[0131] Please see Figure 12 This is a circuit diagram of the eleventh embodiment of the single-stage AC / DC resonant converter disclosed herein, with reference to other relevant documents. Figures 2-11 . Figure 12 The main characteristic is that the primary-side circuit A lacks a slow-speed arm, instead employing a bidirectional on / off fast-speed arm. Furthermore, both the resonant circuit B and the secondary-side circuit C are connected to... Figure 2 Same. Specifically, Figure 12 The three primary-side switching circuits 1 each include a filter circuit 3 and a switching circuit 4. The filter circuit 3 is coupled to one phase of the three-phase AC power supply R, Y, and B, Pac, and the switching circuit 4 is coupled to the filter circuit 3 and the primary-side winding Wp. Specifically, the filter circuit 3 includes an inductor L and a capacitor Cf. Similar to... Figure 2 As described, the main function of inductor L and capacitor Cf is filtering, not as intermediate energy storage components (i.e., not as components that can store large amounts of electricity, such as electrolytic capacitors).

[0132] Furthermore, one end of inductor L is coupled to one end of AC power supply Pac, and one end of capacitor Cf is coupled to the other end of inductor L. The other end of capacitor Cf is coupled to the other end of AC power supply Pac, and capacitor Cf is connected in parallel with switching circuit 4. Switching circuit 4 is similar to... Figure 2Also included are the first switching leg 42 and the second switching leg 44, but the switching legs 42, 44 are replaced with switching modules 422-444, and each of the switching modules 422-444 is a bidirectional switch. Thus, when both switches of the bidirectional switch are turned off, the path of the bidirectional switch is completely disconnected. Specifically, the first switching leg 42 includes a first switching module 422 and a second switching module 424 connected in series, and the first switching module 422 and the second switching module 424 each include switches connected in anti-series (i.e., the direction of the junction diode is opposite). Thus, the first switching leg 42 includes more than four switches. One end of the first switching module 422 and the other end of the second switching module 424 are coupled to the filter circuit 3 (specifically, the first switching leg 42 parallel capacitor Cf), and the other end of the first switching module 422 is coupled to one end of the second switching module 424 to form a first primary side node Pp1.

[0133] The second switching leg 44 includes a third switching module 442 and a fourth switching module 444 connected in series, and the third switching module 442 and the fourth switching module 444 each include switches connected in anti-series. Thus, the second switching leg 44 also includes more than four switches. One end of the third switching module 442 and the other end of the fourth switching module 444 are coupled to the filter circuit 3 (specifically, the second switching leg 44 parallel capacitor Cf), and the other end of the third switching module 442 is coupled to one end of the fourth switching module 444 to form a second primary side node Pp2. The coupling relationship between the first primary side node Pp1 and the second primary side node Pp2 is similar to Figure 2 . One of them is coupled to one end of the primary side winding Wp, and the other is coupled to the other end of the primary side winding Wp and the primary side ground Pgnd1, Pgnd2, Pgnd3. The rest of the detailed coupling mode is similar to Figure 2 , which will not be described here.

[0134] It is worth mentioning that in an embodiment, in addition to the implementation of two switches connected in anti-series, there are many different structures but with the same function, so the structure of the switching module 422-444 can be selectively replaced according to actual needs. That is, as long as the bidirectional switch has the function of bidirectional conduction / off, it should be included in the scope of this embodiment. In addition, the circuit structure and coupling relationship not mentioned in Figure 12 are similar to Figure 2 , and can also achieve similar effects, which will not be described here.

[0135] Please refer to Figure 13 for the circuit diagram of the twelfth embodiment of the single-stage AC / DC resonant converter of the present disclosure, and refer to Figures 2-12 , and refer to Figure 3 , Figure 12 .Figure 13 The circuit architecture is mainly for Figure 3 , Figure 12 This is a combination of some circuit architectures, which can achieve the corresponding effects described above. Mainly, the secondary winding Ws is like... Figure 3 It uses a delta-connected structure. For further details on the circuit structure and features, please refer to [reference needed]. Figure 3 , Figure 12 This will not be elaborated upon further here.

[0136] Please see Figure 14 This is a circuit diagram of the thirteenth embodiment of the single-stage AC / DC resonant converter disclosed herein, with reference to other relevant documents. Figures 2-13 And consulted repeatedly Figure 4 , Figure 12 . Figure 14 The circuit architecture is mainly for Figure 4 , Figure 12 This is a combination of some circuit architectures, which can achieve the corresponding effects described above. Mainly, the secondary winding Ws is like... Figure 4 It features a Y-shaped wiring structure. Further details regarding the circuit structure and its characteristics can be found in the reference book. Figure 4 , Figure 12 This will not be elaborated upon further here.

[0137] Please see Figure 15 This is a circuit diagram of the fourteenth embodiment of the single-stage AC / DC resonant converter disclosed herein, with reference to other relevant documents. Figures 2-14 . Figure 15 The secondary side circuit C and Figure 5 Exactly the same, and filter circuit 3 and Figure 12 They are exactly the same, the only difference being the switching circuit 4. Specifically, Figure 15 The switching circuit 4 is similar to Figure 5 However, the first switching switch Q1 and the second switching switch Q2 are replaced by the first switching module 422 and the second switching module 424, respectively. Furthermore, the first switching module 422 and the second switching module 424 are also bidirectional switches, each comprising switches connected in reverse series (i.e., the diodes at the junctions are in opposite directions). Similarly, besides the implementation of two switches connected in reverse series, there are various other implementations with different structures but the same function, which will not be elaborated upon here.

[0138] Furthermore, one end of the first switch module 422 and the second switch module 424 are coupled to the filter circuit 3 (specifically, one end of the capacitor Cf, and the other end of the capacitor Cf is coupled to the primary-side ground terminals Pgnd1, Pgnd2, and Pgnd3), and the other ends of the first switch module 422 and the second switch module 424 are respectively coupled to one end of the first primary-side winding Wp1 and the second primary-side winding Wp2. Other coupling relationships and their achievable effects can be found in the references. Figure 5, Figure 12 This will not be elaborated upon further here.

[0139] Please see Figure 16 , Figure 17 , Figure 18 The circuit diagrams are for the fifteenth to seventeenth embodiments of the single-stage AC / DC resonant converter disclosed herein, and can be further referenced. Figures 2-14 And consulted repeatedly Figures 2-4 , Figure 15 . Figure 16 , Figure 17 , Figure 18 The main circuit architectures are as follows: Figure 2 and Figure 15 , Figure 3 and Figure 15 , Figure 4 and Figure 15 This involves combining parts of the circuit architecture to achieve the corresponding effects described above. Further details regarding the circuit structure and features can be found in the accompanying documentation. Figures 2-4 , Figure 15 This will not be elaborated upon further here.

[0140] However, the above description is only a detailed description and accompanying drawings of preferred embodiments of the present invention. The features of the present invention are not limited thereto and are not intended to limit the present invention. The full scope of the present invention should be determined by the following claims. All embodiments that conform to the spirit of the claims of the present invention and similar variations thereof should be included in the scope of the present invention. Any variations or modifications that can be easily conceived by those skilled in the art within the field of the present invention can be covered by the following claims.

Claims

1. A single-stage AC / DC resonant converter for converting a three-phase AC power supply into a DC power supply, wherein the single-stage AC / DC resonant converter comprises: The primary-side circuit includes three sets of primary-side switching circuits, each set of which is coupled to one phase of the three-phase AC power supply. Each of the three sets of primary-side switching circuits includes: A rectifier circuit, including rectifier bridge arms and capacitors connected in parallel with the rectifier bridge arms; A switching circuit is used to couple the capacitor. The resonant circuit includes three sets of transformers, the primary windings of the three sets of transformers are respectively coupled to the switching circuits of the three primary-side switching circuits, and the secondary windings of the three sets of transformers form a common secondary winding. The secondary side circuit includes a set of secondary side switching circuits, and the secondary side switching circuits are coupled to the secondary side common winding.

2. The single-stage AC / DC resonant converter according to claim 1, wherein the secondary-side switching circuit comprises: The first-stage side bridge arm includes a first-stage side switch and a second-stage side switch connected in series, and a first-stage side node is formed between the first-stage side switch and the second-stage side switch; and The second-stage side bridge arm is connected in parallel with the first-stage side bridge arm, and includes a third-stage side switch and a fourth-stage side switch connected in series, with the third-stage side switch and the fourth-stage side switch forming a second-stage side node; Wherein, the first end of the secondary winding of the three sets of transformers is coupled to the secondary grounding terminal, and the second end of the secondary winding of the three sets of transformers is coupled to a node; the node is coupled to one of the first secondary node and the second secondary node, and the other of the first secondary node and the second secondary node is coupled to the secondary grounding terminal.

3. The single-stage AC / DC resonant converter according to claim 1, wherein the secondary-side switching circuit comprises: The first-stage side arm includes a first-stage side switch and a second-stage side switch connected in series, wherein a first-stage side node is included between the first-stage side switch and the second-stage side switch; A second-stage side bridge arm, connected in parallel to the first-stage side bridge arm, and including a third-stage side switch and a fourth-stage side switch connected in series, wherein a second-stage side node is included between the third-stage side switch and the fourth-stage side switch; and The third-stage side arm is connected in parallel with the first-stage side arm and includes a fifth-stage side switch and a sixth-stage side switch connected in series, wherein a third-stage side node is included between the fifth-stage side switch and the sixth-stage side switch; The first end of the secondary winding of the three sets of transformers is coupled to the first secondary node, the second secondary node and the third secondary node respectively, and the second end of the secondary winding of the three sets of transformers is coupled to the node.

4. The single-stage AC / DC resonant converter according to claim 1, wherein the secondary-side switching circuit comprises: The first-stage side arm includes a first-stage side switch and a second-stage side switch connected in series, and a first-stage side node is formed between the first-stage side switch and the second-stage side switch; The second-stage side bridge arm is connected in parallel to the first-stage side bridge arm, and includes a third-stage side switch and a fourth-stage side switch connected in series, forming a second-stage side node between the third-stage side switch and the fourth-stage side switch; and The third-stage side arm is connected in parallel with the first-stage side arm and includes a fifth-stage side switch and a sixth-stage side switch connected in series, with the fifth-stage side switch and the sixth-stage side switch forming a third-stage side node; The secondary windings of the three sets of transformers are sequentially coupled end to end to form a first node, a second node, and a third node, and the first node, the second node, and the third node are respectively coupled to the first secondary node, the second secondary node, and the third secondary node.

5. The single-stage AC / DC resonant converter according to claim 1, wherein the rectifier circuit further comprises: An inductor, coupled to one end of one phase of the AC power supply; The rectifier bridge arm includes a first rectifier bridge arm and a second rectifier bridge arm connected in parallel with the capacitor, and the first rectifier bridge arm and the second rectifier bridge arm are respectively coupled to the inductor and the other end of one of the phase AC power supplies.

6. The single-stage AC / DC resonant converter according to claim 1, wherein the switching circuit comprises: The first switching switch is coupled to one end of the capacitor, and the other end of the capacitor is coupled to the primary side ground terminal. and The second switching switch is coupled to one end of the capacitor; Each transformer's primary winding includes a first primary winding and a second primary winding connected in series, with a center tap formed between the first primary winding and the second primary winding; one end of the first primary winding is coupled to the other end of the first switching switch, one end of the second primary winding is coupled to the other end of the second switching switch, and the center tap is coupled to the primary grounding terminal.

7. The single-stage AC / DC resonant converter according to claim 1, wherein the switching circuit comprises: The first switching bridge arm is connected in parallel with the capacitor and includes a first switching switch and a second switching switch connected in series, with a first primary side node formed between the first switching switch and the second switching switch. and The second switching bridge arm is connected in parallel with the capacitor and includes a third switching switch and a fourth switching switch connected in series, with the third switching switch and the fourth switching switch forming a second primary side node. Wherein, one of the first primary side node and the second primary side node is coupled to the primary side grounding terminal, and the other of the first primary side node and the second primary side node is coupled to the primary side winding of one of the transformers.

8. The single-stage AC / DC resonant converter according to claim 7, wherein the capacitor is connected in parallel to the rectifier bridge arm, and includes: The first rectifier switch is coupled to one end of the capacitor; and The second rectifier switch has one end coupled to the other end of the first rectifier switch to form a third primary side node, and the other end coupled to the other end of the capacitor; The switching circuit further includes: A first inductor, one end of which is coupled to one end of one phase of the AC power supply, and the other end of which is coupled to the first primary side node; and The second inductor has one end coupled to one end of one phase of the AC power supply, and the other end coupled to the second primary side node; The third primary side node is coupled to the other end of one of the phase AC power supplies.

9. A single-stage AC / DC resonant converter for converting a three-phase AC power supply into a DC power supply, wherein the single-stage AC / DC resonant converter comprises: The primary-side circuit includes three sets of primary-side switching circuits, and each of the three sets of primary-side switching circuits includes: The filter circuit is coupled to one phase of the three-phase AC power supply respectively; A switching circuit, coupled to the filter circuit; The resonant circuit includes three sets of transformers, the primary windings of the three sets of transformers are respectively coupled to the switching circuits of the three primary-side switching circuits, and the secondary windings of the three sets of transformers form a common secondary winding. The secondary side circuit includes a set of secondary side switching circuits, and the secondary side switching circuits are coupled to the secondary side common winding.

10. The single-stage AC / DC resonant converter according to claim 9, wherein the secondary-side switching circuit comprises: The first-stage side bridge arm includes a first-stage side switch and a second-stage side switch connected in series, and a first-stage side node is formed between the first-stage side switch and the second-stage side switch; and The second-stage side bridge arm is connected in parallel with the first-stage side bridge arm, and includes a third-stage side switch and a fourth-stage side switch connected in series. The third-stage side switch and the fourth-stage side switch form a second-stage side node. Wherein, the first end of the secondary winding of the three sets of transformers is coupled to the secondary grounding terminal, and the second end of the secondary winding of the three sets of transformers is coupled to a node; the node is coupled to one of the first secondary node and the second secondary node, and the other of the first secondary node and the second secondary node is coupled to the secondary grounding terminal.

11. The single-stage AC / DC resonant converter according to claim 9, wherein the secondary-side switching circuit comprises: The first-stage side arm includes a first-stage side switch and a second-stage side switch connected in series, wherein a first-stage side node is included between the first-stage side switch and the second-stage side switch; A second-stage side bridge arm, connected in parallel to the first-stage side bridge arm, and including a third-stage side switch and a fourth-stage side switch connected in series, wherein a second-stage side node is included between the third-stage side switch and the fourth-stage side switch; and The third-stage side arm is connected in parallel with the first-stage side arm and includes a fifth-stage side switch and a sixth-stage side switch connected in series, wherein a third-stage side node is included between the fifth-stage side switch and the sixth-stage side switch; The first end of the secondary winding of the three sets of transformers is coupled to the first secondary node, the second secondary node and the third secondary node respectively, and the second end of the secondary winding of the three sets of transformers is coupled to the node.

12. The single-stage AC / DC resonant converter according to claim 9, wherein the secondary-side switching circuit comprises: The first-stage side arm includes a first-stage side switch and a second-stage side switch connected in series, and a first-stage side node is formed between the first-stage side switch and the second-stage side switch; The second-stage side bridge arm is connected in parallel to the first-stage side bridge arm, and includes a third-stage side switch and a fourth-stage side switch connected in series, forming a second-stage side node between the third-stage side switch and the fourth-stage side switch; and The third-stage side arm is connected in parallel with the first-stage side arm and includes a fifth-stage side switch and a sixth-stage side switch connected in series, with the fifth-stage side switch and the sixth-stage side switch forming a third-stage side node; The secondary windings of the three sets of transformers are sequentially coupled end to end to form a first node, a second node, and a third node, and the first node, the second node, and the third node are respectively coupled to the first secondary node, the second secondary node, and the third secondary node.

13. The single-stage AC / DC resonant converter according to claim 9, wherein the filter circuit comprises: An inductor, one end of which is coupled to one end of one phase of the AC power supply; and The capacitor has one end coupled to the other end of the inductor, and the other end coupled to the other end of one phase of the AC power supply. The switching circuit is connected in parallel with the capacitor.

14. The single-stage AC / DC resonant converter according to claim 9, wherein the switching circuit comprises: The first switching bridge arm includes a first switching module and a second switching module connected in series, wherein one end of the first switching module and the other end of the second switching module are coupled to the filter circuit, and the other end of the first switching module is coupled to one end of the second switching module to form a first primary side node. The second switching bridge arm is connected in parallel with the first switching bridge arm and includes a third switch module and a fourth switch module connected in series. One end of the third switch module and the other end of the fourth switch module are coupled to the filter circuit, and the other end of the third switch module is coupled to one end of the fourth switch module to form a second primary side node. Wherein, one of the first primary side node and the second primary side node is coupled to one end of the primary side winding, and the other of the first primary side node and the second primary side node is coupled to the other end of the primary side winding and the primary side grounding terminal.

15. The single-stage AC / DC resonant converter according to claim 9, wherein the switching circuit comprises: The first switching module is coupled to the filter circuit at one end; and The second switching module is coupled to the filter circuit at one end; Each transformer's primary winding includes a first primary winding and a second primary winding connected in series, with a center tap formed between the first primary winding and the second primary winding; one end of the first primary winding is coupled to the other end of the first switching module, one end of the second primary winding is coupled to the other end of the second switching module, and the center tap is coupled to the primary grounding terminal.

16. A single-stage AC / DC resonant converter for converting a three-phase AC power supply into a DC power supply, wherein the single-stage AC / DC resonant converter comprises: The primary side circuit includes three sets of primary side switching circuits, each of which is coupled to one phase of the three-phase AC power supply, and each of the three sets of primary side switching circuits includes a switching circuit. The resonant circuit includes three sets of transformers, the primary windings of the three sets of transformers being respectively coupled to the switching circuits of the three primary-side switching circuits; The secondary side circuit includes three sets of secondary side switching circuits. The input terminals of the three sets of secondary side switching circuits are coupled to the secondary windings of the three transformers, and the output terminals of the three sets of secondary side switching circuits are connected in parallel.

17. The single-stage AC / DC resonant converter according to claim 16, wherein the three sets of secondary-side switching circuits respectively include: The first-stage side bridge arm includes a first-stage side switch and a second-stage side switch connected in series, and a first-stage side node is formed between the first-stage side switch and the second-stage side switch; and The second-stage side bridge arm is connected in parallel with the first-stage side bridge arm, and includes a third-stage side switch and a fourth-stage side switch connected in series, with the third-stage side switch and the fourth-stage side switch forming a second-stage side node; Wherein, one of the first-stage side node and the second-stage side node is coupled to the secondary winding of one of the transformers, and the other of the first-stage side node and the second-stage side node is coupled to the secondary grounding terminal.

18. The single-stage AC / DC resonant converter according to claim 16, wherein the three sets of primary-side switching circuits further include: A rectifier circuit, including rectifier bridge arms and capacitors connected in parallel with the rectifier bridge arms; An inductor, coupled to one end of one phase of the AC power supply; The first switching module is coupled to the capacitor at one end; and The second switching module is coupled to the capacitor at one end; Each transformer's primary winding includes a first primary winding and a second primary winding connected in series, with a center tap formed between the first primary winding and the second primary winding; one end of the first primary winding is coupled to the other end of the first switching module, one end of the second primary winding is coupled to the other end of the second switching module, and the center tap is coupled to the primary grounding terminal.

19. The single-stage AC / DC resonant converter according to claim 16, wherein the three sets of primary-side switching circuits further include: A filter circuit, comprising an inductor and a capacitor, wherein one end of the inductor and the other end of the capacitor are respectively coupled to the two ends of one phase of the AC power supply, and the other end of the inductor is coupled to one end of the capacitor; One end of the capacitor is coupled to the switching circuit, and the other end of the capacitor is coupled to the primary side ground terminal.

20. The single-stage AC / DC resonant converter according to claim 19, wherein the switching circuit comprises: The first switching module is coupled to the capacitor at one end; and The second switching module is coupled to the capacitor at one end; Each transformer's primary winding includes a first primary winding and a second primary winding connected in series, with a center tap formed between the first primary winding and the second primary winding; one end of the first primary winding is coupled to the other end of the first switching module, one end of the second primary winding is coupled to the other end of the second switching module, and the center tap is coupled to the primary grounding terminal.

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