A three-phase LLC transformer current-sharing topology circuit

Abstract

The application discloses a three-phase LLC transformer current sharing topology circuit, which comprises a transformer module, a primary side resonance circuit connected to the primary side of the transformer module, and an inductance current sharing module and a rectifier circuit connected to the secondary side of the transformer module in sequence; the transformer module comprises a first transformer, a second transformer and a third transformer; the inductance current sharing module comprises a first inductance current sharing unit, a second inductance current sharing unit and a third inductance current sharing unit; the first inductance current sharing unit is connected between two secondary side windings of the first transformer and the rectifier circuit, the second inductance current sharing unit is connected between two secondary side windings of the second transformer and the rectifier circuit, and the third inductance current sharing unit is connected between two secondary side windings of the third transformer and the rectifier circuit; through the inductance effect, the phenomenon that the two windings of the transformer secondary side are not current shared due to the asymmetry of self-inductance of the two secondary side windings of the transformer can be prevented.

Description

Technical Field

[0001] This utility model relates to the field of current sharing, and more specifically, to a current sharing topology circuit for a three-phase LLC transformer. Background Technology

[0002] In a three-phase LLC circuit, the primary and secondary sides are connected in a star configuration, and a single transformer has one winding on the primary side and two windings on the secondary side. Due to the winding method, one of the secondary windings of the transformer may have an excessively high self-inductance. In a three-phase LLC circuit, if the self-inductance of the two secondary windings of a single transformer is unbalanced, it will lead to uneven current distribution between the two secondary windings. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a three-phase LLC transformer current sharing topology circuit that can realize current sharing in the secondary winding of the transformer, in view of the above-mentioned defects of the prior art.

[0004] The technical solution adopted by this utility model to solve its technical problem is: to construct a three-phase LLC transformer current sharing topology circuit, including a transformer module, a primary resonant circuit connected to the primary side of the transformer module, and an inductor current sharing module and a rectifier circuit connected sequentially to the secondary side of the transformer module. The transformer module includes a first transformer, a second transformer, and a third transformer; the first transformer, the second transformer, and the third transformer each include two secondary windings; The inductor current sharing module includes a first inductor current sharing unit, a second inductor current sharing unit, and a third inductor current sharing unit; The first inductor current sharing unit is connected between the two secondary windings of the first transformer and the rectifier circuit, the second inductor current sharing unit is connected between the two secondary windings of the second transformer and the rectifier circuit, and the third inductor current sharing unit is connected between the two secondary windings of the third transformer and the rectifier circuit, so as to share the secondary output current of the first transformer, the second transformer and the third transformer.

[0005] In the three-phase LLC transformer current sharing topology circuit described in this utility model, the first transformer includes a first secondary winding and a second secondary winding, the second transformer includes a third secondary winding and a fourth secondary winding, and the third transformer includes a fifth secondary winding and a sixth secondary winding. The rectifier circuit includes a first rectifier unit and a second rectifier unit.

[0006] In the three-phase LLC transformer current sharing topology circuit described in this utility model, the first inductor current sharing unit includes a first common-mode inductor, the second inductor current sharing unit includes a second common-mode inductor, and the third inductor current sharing unit includes a third common-mode inductor.

[0007] In the current-sharing topology of the three-phase LLC transformer described in this utility model, the first end of the first secondary winding is connected to the first end of the first common-mode inductor, the second end of the first common-mode inductor is connected to the first end of the first rectifier unit, the first end of the second secondary winding is connected to the first end of the second rectifier unit, the second end of the second secondary winding is connected to the third end of the first common-mode inductor, the fourth end of the first common-mode inductor is connected to the fourth end of the second common-mode inductor and the fourth end of the third common-mode inductor; the second end of the first secondary winding is connected to the second end of the third secondary winding and the second end of the fifth secondary winding. The first end of the third secondary winding is connected to the first end of the second common mode inductor, the second end of the second common mode inductor is connected to the second end of the first rectifier unit, the first end of the fourth secondary winding is connected to the second end of the second rectifier unit, and the second end of the fourth secondary winding is connected to the third end of the second common mode inductor. The first end of the fifth secondary winding is connected to the first end of the third common-mode inductor, the second end of the third common-mode inductor is connected to the third end of the first rectifier unit, the first end of the sixth secondary winding is connected to the third end of the second rectifier unit, and the second end of the sixth secondary winding is connected to the third end of the third common-mode inductor.

[0008] In the current-sharing topology of the three-phase LLC transformer described in this utility model, the first end of the first secondary winding is connected to the first end of the first rectifier unit, and the second end of the first secondary winding is connected to the first end of the first common-mode inductor; the second end of the first common-mode inductor is connected to the second end of the second common-mode inductor and the second end of the third common-mode inductor; the first end of the second secondary winding is connected to the third end of the first common-mode inductor, and the fourth end of the first common-mode inductor is connected to the first end of the second rectifier unit; the second end of the second secondary winding is connected to the second end of the fourth secondary winding and the second end of the sixth secondary winding. The first end of the third secondary winding is connected to the second end of the first rectifier unit, and the second end of the third secondary winding is connected to the first end of the second common mode inductor; the first end of the fourth secondary winding is connected to the third end of the second common mode inductor, and the fourth end of the second common mode inductor is connected to the second end of the second rectifier unit. The first end of the fifth secondary winding is connected to the third end of the first rectifier unit, and the second end of the fifth secondary winding is connected to the first end of the third common-mode inductor; the first end of the sixth secondary winding is connected to the third end of the third common-mode inductor, and the fourth end of the third common-mode inductor is connected to the third end of the second rectifier unit.

[0009] In the three-phase LLC transformer current sharing topology circuit described in this utility model, the first inductor current sharing unit includes a first differential mode inductor, the second inductor current sharing unit includes a second differential mode inductor, and the third inductor current sharing unit includes a third differential mode inductor.

[0010] In the three-phase LLC transformer current-sharing topology circuit described in this utility model, the first end of the first secondary winding is connected to the first end of the first rectifier unit, and the second end of the first secondary winding is connected to the second end of the third secondary winding and the second end of the fifth secondary winding; the first end of the second secondary winding is connected to the second end of the second rectifier unit via the first differential mode inductor; the second end of the second secondary winding is connected to the second end of the fourth secondary winding and the second end of the sixth secondary winding. The first end of the third secondary winding is connected to the second end of the first rectifier unit, and the first end of the fourth secondary winding is connected to the second end of the second rectifier unit via the second differential mode inductor. The first end of the fifth secondary winding is connected to the third end of the first rectifier unit, and the first end of the sixth secondary winding is connected to the third end of the second rectifier unit via the third differential mode inductor. The self-inductance of the first secondary winding is greater than that of the second secondary winding, the self-inductance of the third secondary winding is greater than that of the fourth secondary winding, and the self-inductance of the fifth secondary winding is greater than that of the sixth secondary winding.

[0011] In the three-phase LLC transformer current sharing topology circuit described in this utility model, the first rectifier unit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode; The anode of the first diode and the cathode of the second diode are connected to the first terminal of the first rectifier unit; the anode of the third diode and the cathode of the fourth diode are connected to the second terminal of the first rectifier unit; and the anode of the fifth diode and the cathode of the sixth diode are connected to the third terminal of the first rectifier unit. The cathodes of the first diode, the third diode, and the fifth diode are connected to the positive output terminal; and the cathodes of the second diode, the fourth diode, and the sixth diode are connected to the negative output terminal.

[0012] In the three-phase LLC transformer current sharing topology circuit described in this utility model, the second rectifier unit includes a seventh diode, an eighth diode, a ninth diode, a tenth diode, an eleventh diode, and a twelfth diode; The anode of the seventh diode and the cathode of the eighth diode are connected to the first terminal of the second rectifier unit; the anode of the ninth diode and the cathode of the tenth diode are connected to the second terminal of the second rectifier unit; and the anode of the eleventh diode and the cathode of the twelfth diode are connected to the third terminal of the second rectifier unit. The cathodes of the seventh diode, the ninth diode, and the eleventh diode are connected to the positive output terminal. The cathodes of the eighth diode, the tenth diode, and the twelfth diode are connected to the negative output terminal.

[0013] In the three-phase LLC transformer current sharing topology circuit described in this utility model, the primary-side resonant circuit includes a first switching network, a second switching network, a third switching network, a first resonant unit, a second resonant unit, and a third resonant unit; The first terminal of the first switch network, the second switch network, and the third switch network are respectively connected to the positive input terminal, and the second terminal is respectively connected to the negative input terminal. The output terminal of the first switching network is connected to the first terminal of the primary winding of the first transformer via the first resonant unit; The output of the second switching network is connected to the first end of the primary winding of the second transformer via the second resonant unit; The output terminal of the third switching network is connected to the first terminal of the primary winding of the third transformer via the third resonant unit; The second end of the primary winding of the first transformer is connected to the second end of the primary winding of the second transformer and the second end of the primary winding of the third transformer.

[0014] This utility model discloses a three-phase LLC transformer current-sharing topology circuit, comprising a transformer module, a primary resonant circuit connected to the primary side of the transformer module, and an inductor current-sharing module and a rectifier circuit sequentially connected to the secondary side of the transformer module. The transformer module includes a first transformer, a second transformer, and a third transformer. The inductor current-sharing module includes a first inductor current-sharing unit, a second inductor current-sharing unit, and a third inductor current-sharing unit. The first inductor current-sharing unit is connected between the two secondary windings of the first transformer and the rectifier circuit; the second inductor current-sharing unit is connected between the two secondary windings of the second transformer and the rectifier circuit; and the third inductor current-sharing unit is connected between the two secondary windings of the third transformer and the rectifier circuit. Through inductance, the uneven current distribution between the two secondary windings of the transformer caused by the asymmetry of self-inductance can be prevented. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a schematic block diagram of a preferred embodiment of the three-phase LLC transformer current sharing topology circuit of this utility model; Figure 2 This is a circuit diagram of the first preferred embodiment of the three-phase LLC transformer current sharing topology circuit of this utility model; Figure 3 This is a circuit diagram of a second preferred embodiment of the three-phase LLC transformer current sharing topology circuit of this utility model; Figure 4 This is a circuit diagram of the third preferred embodiment of the three-phase LLC transformer current sharing topology circuit of this utility model. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0017] Figure 1 This is a schematic block diagram of a preferred embodiment of the three-phase LLC transformer current-sharing topology circuit of this utility model. (See diagram for example.) Figure 1As shown, the three-phase LLC transformer current-sharing topology circuit of this utility model includes a transformer module 200, a primary resonant circuit 100 connected to the primary side of the transformer module 200, and an inductor current-sharing module 300 and a rectifier circuit 400 sequentially connected to the secondary side of the transformer module 200. The transformer module 200 includes a first transformer T1, a second transformer T2, and a third transformer T3. The first transformer T1, the second transformer T2, and the third transformer T3 each include two secondary windings. For example, the first transformer T1 includes a first secondary winding T1_1 and a second secondary winding T1_2, the second transformer T2 includes a third secondary winding T2_1 and a fourth secondary winding T2_2, and the third transformer T3 includes a fifth secondary winding T3_1 and a sixth secondary winding T3_2.

[0018] The inductor current sharing module 300 includes a first inductor current sharing unit 310, a second inductor current sharing unit 320, and a third inductor current sharing unit 330. The first inductor current sharing unit 310 is connected between the two secondary windings of the first transformer T1 and the rectifier circuit 400, the second inductor current sharing unit 320 is connected between the two secondary windings of the second transformer T2 and the rectifier circuit 400, and the third inductor current sharing unit 330 is connected between the two secondary windings of the third transformer T3 and the rectifier circuit 400, so as to share the secondary output current of the first transformer T1, the second transformer T2, and the third transformer T3.

[0019] In a preferred embodiment of the present invention, the first inductor current sharing unit 310, the second inductor current sharing unit 320 and the third inductor current sharing unit 330 may respectively include a common-mode inductor or a differential-mode inductor.

[0020] In a preferred embodiment of this utility model, the primary-side resonant circuit 100 may include a first switching network, a second switching network, a third switching network, a first resonant unit, a second resonant unit, and a third resonant unit; the first terminals of the first switching network, the second switching network, and the third switching network are respectively connected to the positive input terminal, and the second terminals are respectively connected to the negative input terminal; the output terminal of the first switching network is connected to the first terminal of the primary winding of the first transformer T1 via the first resonant unit; the output terminal of the second switching network is connected to the first terminal of the primary winding of the second transformer T2 via the second resonant unit; the output terminal of the third switching network is connected to the first terminal of the primary winding of the third transformer T3 via the third resonant unit; the second terminal of the primary winding of the first transformer T1 is connected to the second terminal of the primary winding of the second transformer T2 and the second terminal of the primary winding of the third transformer T3. The first switching network, the second switching network, and the third switching network may each include a half-bridge and a full-bridge switching transistors. The first resonant unit, the second resonant unit, and the third resonant unit each include a resonant capacitor and a resonant inductor connected in series.

[0021] In this invention, the first switch network, the second switch network, and the third switch network include, but are not limited to, bridge circuits, such as three-level full-bridge or phase-shifted full-bridge. The switching transistors used include, but are not limited to, Si MOS, IGBT, GaN MOS, and SiC MOS.

[0022] In a preferred embodiment of the present invention, the first rectifier unit 210 and the second rectifier unit 220 may include a switching transistor rectifier unit or a diode rectifier unit.

[0023] In the current sharing topology of the three-phase LLC transformer of this utility model, the first inductor current sharing unit is connected between the two secondary windings of the first transformer and the rectifier circuit, the second inductor current sharing unit is connected between the two secondary windings of the second transformer and the rectifier circuit, and the third inductor current sharing unit is connected between the two secondary windings of the third transformer and the rectifier circuit. The inductance can prevent the uneven current distribution between the two secondary windings of the transformer caused by the asymmetry of self-inductance in the two secondary windings of the transformer.

[0024] Figure 2 This is a circuit diagram of a first preferred embodiment of the three-phase LLC transformer current-sharing topology circuit of this utility model. Combined with... Figures 1-2As can be seen, the three-phase LLC transformer current-sharing topology circuit of this utility model includes a transformer module 200, a primary resonant circuit 100 connected to the primary side of the transformer module 200, and an inductor current-sharing module 300 and a rectifier circuit 400 sequentially connected to the secondary side of the transformer module 200; the transformer module 200 includes a first transformer T1, a second transformer T2, and a third transformer T3. The inductor current-sharing module 300 includes a first inductor current-sharing unit 310, a second inductor current-sharing unit 320, and a third inductor current-sharing unit 330. The first transformer T1 includes a first secondary winding T1_1 and a second secondary winding T1_2, the second transformer T2 includes a third secondary winding T2_1 and a fourth secondary winding T2_2, and the third transformer T3 includes a fifth secondary winding T3_1 and a sixth secondary winding T3_2; the rectifier circuit 400 includes a first rectifier unit and a second rectifier unit. The first inductor current sharing unit 310 includes a first common-mode inductor L1, the second inductor current sharing unit 320 includes a second common-mode inductor L2, and the third inductor current sharing unit 330 includes a third common-mode inductor L3.

[0025] like Figure 2 As shown, the first end of the first secondary winding T1_1 is connected to the first end of the first common-mode inductor L1, the second end of the first common-mode inductor L1 is connected to the first end of the first rectifier unit, the first end of the second secondary winding T1_2 is connected to the first end of the second rectifier unit, the second end of the second secondary winding T1_2 is connected to the third end of the first common-mode inductor L1, and the fourth end of the first common-mode inductor L1 is connected to the fourth end of the second common-mode inductor L2 and the fourth end of the third common-mode inductor L3; the second end of the first secondary winding T1_1 is connected to the second end of the third secondary winding T2_1 and the second end of the fifth secondary winding T3_1; the third secondary winding T2_1... The first end of the fourth secondary winding T2_2 is connected to the first end of the second common-mode inductor L2, and the second end of the second common-mode inductor L2 is connected to the second end of the first rectifier unit. The first end of the fourth secondary winding T2_2 is connected to the second end of the second rectifier unit, and the second end of the fourth secondary winding T2_2 is connected to the third end of the second common-mode inductor L2. The first end of the fifth secondary winding T3_1 is connected to the first end of the third common-mode inductor L3, and the second end of the third common-mode inductor L3 is connected to the third end of the first rectifier unit. The first end of the sixth secondary winding T3_2 is connected to the third end of the second rectifier unit, and the second end of the sixth secondary winding T3_2 is connected to the third end of the third common-mode inductor L3.

[0026] Here, the first and third terminals of the first common-mode inductor L1, the second common-mode inductor L2, and the third common-mode inductor L3 are terminals with the same name, and the second and fourth terminals are terminals with different names.

[0027] like Figure 2 As shown, the first rectifier unit includes diodes D_5, D2_5, D2_5, D4_5, D5_5, and D6_5; the anode of diode D_5 and the cathode of diode D2_5 are connected to the first terminal of the first rectifier unit 210, the anode of diode D2_5 and the cathode of diode D4_5 are connected to the second terminal of the first rectifier unit 210, and the anode of diode D5_5 and the cathode of diode D6_5 are connected to the third terminal of the first rectifier unit 210; the cathodes of diodes D_5, D2_5, and D5_5 are connected to the positive output terminal; and the cathodes of diodes D2_5, D4_5, and D6_5 are connected to the negative output terminal. Further as... Figure 2 As shown, the first rectifier unit 210 further includes a first output capacitor and a first output resistor; the first output capacitor and the first output resistor are connected in series between the output positive terminal and the output negative terminal.

[0028] The second rectifier unit 220 includes diodes D7_5, D8_5, D9_5, D10_5, D11_5, and D12_5. The anode of diode D7_5 and the cathode of diode D8_5 are connected to the first terminal of the second rectifier unit 220; the anode of diode D9_5 and the cathode of diode D10_5 are connected to the second terminal of the second rectifier unit 220; and the anode of diode D11_5 and the cathode of diode D12_5 are connected to the third terminal of the second rectifier unit 220. The cathodes of diodes D7_5, D9_5, and D11_5 are connected to the positive output terminal; and the cathodes of diodes D8_5, D10_5, and D12_5 are connected to the negative output terminal. Further as... Figure 2 As shown, the second rectifier unit 220 further includes a second output capacitor and a second output resistor; the second output capacitor and the second output resistor are connected in series between the output positive terminal and the output negative terminal.

[0029] Further as Figure 2As shown, the primary-side resonant circuit 100 includes a first switching network, a second switching network, a third switching network, a first resonant unit, a second resonant unit, and a third resonant unit. The first terminals of the first, second, and third switching networks are respectively connected to the positive input terminal, and their second terminals are respectively connected to the negative input terminal. The output terminal of the first switching network is connected to the first terminal of the primary winding of the first transformer T1 via the first resonant unit; the output terminal of the second switching network is connected to the first terminal of the primary winding of the second transformer T2 via the second resonant unit; the output terminal of the third switching network is connected to the first terminal of the primary winding of the third transformer T3 via the third resonant unit; the second terminal of the primary winding of the first transformer T1 is connected to the second terminal of the primary winding of the second transformer T2 and the second terminal of the primary winding of the third transformer T3. The first, second, and third switching networks each include a switching transistor half-bridge; the first, second, and third resonant units each include a resonant capacitor and a resonant inductor connected in series.

[0030] Figure 3 This is a circuit diagram of a second preferred embodiment of the current sharing topology circuit of the three-phase LLC transformer of this utility model. Figure 3 and Figure 2 The difference is that, Figure 3 The connection method between the secondary winding of the transformer and the common mode inductor is different, so the difference will be explained as follows.

[0031] like Figure 3As shown, the first end of the first secondary winding T1_1 is connected to the first end of the first rectifier unit, and the second end of the first secondary winding T1_1 is connected to the first end of the first common-mode inductor L1; the second end of the first common-mode inductor L1 is connected to the second end of the second common-mode inductor L2 and the second end of the third common-mode inductor L3; the first end of the second secondary winding T1_2 is connected to the third end of the first common-mode inductor L1, and the fourth end of the first common-mode inductor L1 is connected to the first end of the second rectifier unit; the second end of the second secondary winding T1_2 is connected to the second end of the fourth secondary winding T2_2 and the second end of the sixth secondary winding T3_2; the third secondary winding T2_1... The first end of the third secondary winding T2_1 is connected to the second end of the first rectifier unit; the second end of the third secondary winding T2_1 is connected to the first end of the second common-mode inductor L2; the first end of the fourth secondary winding T2_2 is connected to the third end of the second common-mode inductor L2; the fourth end of the second common-mode inductor L2 is connected to the second end of the second rectifier unit; the first end of the fifth secondary winding T3_1 is connected to the third end of the first rectifier unit; the second end of the fifth secondary winding T3_1 is connected to the first end of the third common-mode inductor L3; the first end of the sixth secondary winding T3_2 is connected to the third end of the third common-mode inductor L3; the fourth end of the third common-mode inductor L3 is connected to the third end of the second rectifier unit.

[0032] Figure 4 This is a circuit diagram of the third preferred embodiment of the three-phase LLC transformer current sharing topology circuit of this utility model. Figure 4 and Figure 2 The difference is that, in Figure 4 The transformer uses a differential-mode inductor instead of a common-mode inductor, and the connection method of the differential-mode inductor is different from that of the transformer secondary winding. Therefore, the differences are explained below.

[0033] like Figure 4 As shown, the first transformer T1 includes a first secondary winding T1_1 and a second secondary winding T1_2; the second transformer T2 includes a third secondary winding T2_1 and a fourth secondary winding T2_2; and the third transformer T3 includes a fifth secondary winding T3_1 and a sixth secondary winding T3_2. The rectifier circuit 400 includes a first rectifier unit and a second rectifier unit. The first inductor current sharing unit 310 includes a first differential mode inductor L1; the second inductor current sharing unit 320 includes a second differential mode inductor L2; and the third inductor current sharing unit 330 includes a third differential mode inductor L3.

[0034] like Figure 4As shown, the first end of the first secondary winding T1_1 is connected to the first end of the first rectifier unit, and the second end of the first secondary winding T1_1 is connected to the second end of the third secondary winding T2_1 and the second end of the fifth secondary winding T3_1; the first end of the second secondary winding T1_2 is connected to the second end of the second rectifier unit via the first differential mode inductor L1; the second end of the second secondary winding T1_2 is connected to the second end of the fourth secondary winding T2_2 and the second end of the sixth secondary winding T3_2; the first end of the third secondary winding T2_1 is connected to the second end of the first rectifier unit, and the first end of the fourth secondary winding T2_2 is connected to the second end of the second rectifier unit via the second differential mode inductor L2; the first end of the fifth secondary winding T3_1 is connected to the third end of the first rectifier unit, and the first end of the sixth secondary winding T3_2 is connected to the third end of the second rectifier unit via the third differential mode inductor L3. The self-inductances of the first secondary winding T1_1, the third secondary winding T2_1, and the fifth secondary winding T3_1 are equal, the self-inductances of the second secondary winding T1_2, the fourth secondary winding T2_2, and the sixth secondary winding T3_2 are equal, and the self-inductance of the first secondary winding T1_1, the third secondary winding T2_1, and the fifth secondary winding T3_1 is greater than the self-inductance of the second secondary winding T1_2, the fourth secondary winding T2_2, and the sixth secondary winding T3_2.

[0035] Next we will discuss Figures 2-4 The principle of the three-phase LLC transformer current sharing topology circuit shown is explained below. We will use... Figure 4 Taking the differential-mode inductor as an example, this is the existing connection method. The existing three-phase LLC transformer current-sharing topology uses a series connection on the primary winding and a parallel connection on the secondary winding. The three-phase current can achieve good balance without additional control. However, when the self-inductance of the two secondary windings is asymmetrical (due to the winding method, one of the secondary windings has a larger self-inductance), it will lead to uneven current distribution between the two secondary windings. In principle, analyzing the relationship between transformer turns ratio and voltage, different turns ratios result in different voltages in the output windings. Connecting voltage sources with different voltages in parallel requires additional internal circulating current to achieve voltage equality. The magnitude of this circulating current is related to the series inductance; that is, the larger the leakage inductance of the coil, the better the suppression effect on the current unevenness caused by different turns ratios.

[0036] When the coupling coefficients of the two secondary windings are unequal, the currents in the two secondary windings are unequal. In the existing technology, if the self-inductance of the first secondary winding T1_1 is greater than that of the second secondary winding T1_2, the self-inductance of the third secondary winding T2_1 is greater than that of the fourth secondary winding T2_2, the self-inductance of the fifth secondary winding T3_1 is greater than that of the sixth secondary winding T3_2, and the self-inductances of the first secondary winding T1_1, the third secondary winding T2_1, and the fifth secondary winding T3_1 are roughly equal, and the self-inductances of the second secondary winding T1_2, the fourth secondary winding T2_2, and the sixth secondary winding T3_2 are roughly equal, then the current in the first secondary winding T1_1 is less than the current in the second secondary winding T1_2, the current in the third secondary winding T2_1 is less than the current in the fourth secondary winding T2_2, and the current in the fifth secondary winding T3_1 is less than the current in the sixth secondary winding T3_2.

[0037] At this moment, we are Figure 4 In the preferred embodiment shown, differential mode inductors L1~L3 are added to the winding with smaller self-inductance. The coupling of the differential mode inductors makes the self-inductance of the two corresponding secondary windings tend to be balanced, thereby achieving the current sharing effect.

[0038] against Figures 2-3 The preferred embodiment shown employs a common-mode inductor. When the transformer transfers energy to the secondary side, if the currents of the two windings on the secondary side are different, the common-mode inductor generates high impedance through magnetic coupling, which hinders the flow of common-mode current, thereby achieving a current sharing effect.

[0039] Although this utility model has been described through specific embodiments, those skilled in the art should understand that various modifications and equivalent substitutions can be made to this utility model without departing from its scope. Furthermore, various modifications can be made to this utility model for specific situations or materials without departing from its scope. Therefore, this utility model is not limited to the specific embodiments disclosed, but should include all embodiments falling within the scope of the claims of this utility model.

[0040] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A three-phase LLC transformer current sharing topology circuit, characterized in that, It includes a transformer module, a primary resonant circuit connected to the primary side of the transformer module, and an inductor current sharing module and a rectifier circuit connected in sequence to the secondary side of the transformer module. The transformer module includes a first transformer, a second transformer, and a third transformer; the first transformer, the second transformer, and the third transformer each include two secondary windings; The inductor current sharing module includes a first inductor current sharing unit, a second inductor current sharing unit, and a third inductor current sharing unit; The first inductor current sharing unit is connected between the two secondary windings of the first transformer and the rectifier circuit, the second inductor current sharing unit is connected between the two secondary windings of the second transformer and the rectifier circuit, and the third inductor current sharing unit is connected between the two secondary windings of the third transformer and the rectifier circuit, so as to share the secondary output current of the first transformer, the second transformer and the third transformer.

2. The three-phase LLC transformer current sharing topology circuit according to claim 1, characterized in that, The first transformer includes a first secondary winding and a second secondary winding; the second transformer includes a third secondary winding and a fourth secondary winding; and the third transformer includes a fifth secondary winding and a sixth secondary winding. The rectifier circuit includes a first rectifier unit and a second rectifier unit.

3. The three-phase LLC transformer current sharing topology circuit according to claim 2, characterized in that, The first inductor current sharing unit includes a first common-mode inductor, the second inductor current sharing unit includes a second common-mode inductor, and the third inductor current sharing unit includes a third common-mode inductor.

4. The three-phase LLC transformer current sharing topology circuit according to claim 3, characterized in that, The first end of the first secondary winding is connected to the first end of the first common-mode inductor; the second end of the first common-mode inductor is connected to the first end of the first rectifier unit; the first end of the second secondary winding is connected to the first end of the second rectifier unit; the second end of the second secondary winding is connected to the third end of the first common-mode inductor; the fourth end of the first common-mode inductor is connected to the fourth end of the second common-mode inductor and the fourth end of the third common-mode inductor; the second end of the first secondary winding is connected to the second end of the third secondary winding and the second end of the fifth secondary winding. The first end of the third secondary winding is connected to the first end of the second common mode inductor, the second end of the second common mode inductor is connected to the second end of the first rectifier unit, the first end of the fourth secondary winding is connected to the second end of the second rectifier unit, and the second end of the fourth secondary winding is connected to the third end of the second common mode inductor. The first end of the fifth secondary winding is connected to the first end of the third common-mode inductor, the second end of the third common-mode inductor is connected to the third end of the first rectifier unit, the first end of the sixth secondary winding is connected to the third end of the second rectifier unit, and the second end of the sixth secondary winding is connected to the third end of the third common-mode inductor.

5. The three-phase LLC transformer current sharing topology circuit according to claim 3, characterized in that, The first end of the first secondary winding is connected to the first end of the first rectifier unit, and the second end of the first secondary winding is connected to the first end of the first common-mode inductor; the second end of the first common-mode inductor is connected to the second end of the second common-mode inductor and the second end of the third common-mode inductor; the first end of the second secondary winding is connected to the third end of the first common-mode inductor, and the fourth end of the first common-mode inductor is connected to the first end of the second rectifier unit; the second end of the second secondary winding is connected to the second end of the fourth secondary winding and the second end of the sixth secondary winding. The first end of the third secondary winding is connected to the second end of the first rectifier unit, and the second end of the third secondary winding is connected to the first end of the second common mode inductor; the first end of the fourth secondary winding is connected to the third end of the second common mode inductor, and the fourth end of the second common mode inductor is connected to the second end of the second rectifier unit. The first end of the fifth secondary winding is connected to the third end of the first rectifier unit, and the second end of the fifth secondary winding is connected to the first end of the third common-mode inductor; the first end of the sixth secondary winding is connected to the third end of the third common-mode inductor, and the fourth end of the third common-mode inductor is connected to the third end of the second rectifier unit.

6. The three-phase LLC transformer current sharing topology circuit according to claim 2, characterized in that, The first inductor current sharing unit includes a first differential mode inductor, the second inductor current sharing unit includes a second differential mode inductor, and the third inductor current sharing unit includes a third differential mode inductor.

7. The three-phase LLC transformer current sharing topology circuit according to claim 6, characterized in that, The first end of the first secondary winding is connected to the first end of the first rectifier unit; the second end of the first secondary winding is connected to the second end of the third secondary winding and the second end of the fifth secondary winding; the first end of the second secondary winding is connected to the second end of the second rectifier unit via the first differential mode inductor; the second end of the second secondary winding is connected to the second end of the fourth secondary winding and the second end of the sixth secondary winding. The first end of the third secondary winding is connected to the second end of the first rectifier unit, and the first end of the fourth secondary winding is connected to the second end of the second rectifier unit via the second differential mode inductor. The first end of the fifth secondary winding is connected to the third end of the first rectifier unit, and the first end of the sixth secondary winding is connected to the third end of the second rectifier unit via the third differential mode inductor. The self-inductance of the first secondary winding is greater than that of the second secondary winding, the self-inductance of the third secondary winding is greater than that of the fourth secondary winding, and the self-inductance of the fifth secondary winding is greater than that of the sixth secondary winding.

8. The three-phase LLC transformer current-sharing topology circuit according to any one of claims 4 to 7, characterized in that, The first rectifier unit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode; The anode of the first diode and the cathode of the second diode are connected to the first terminal of the first rectifier unit; the anode of the third diode and the cathode of the fourth diode are connected to the second terminal of the first rectifier unit; and the anode of the fifth diode and the cathode of the sixth diode are connected to the third terminal of the first rectifier unit. The cathodes of the first diode, the third diode, and the fifth diode are connected to the positive output terminal; and the cathodes of the second diode, the fourth diode, and the sixth diode are connected to the negative output terminal.

9. The three-phase LLC transformer current-sharing topology circuit according to any one of claims 4 to 7, characterized in that, The second rectifier unit includes a seventh diode, an eighth diode, a ninth diode, a tenth diode, an eleventh diode, and a twelfth diode; The anode of the seventh diode and the cathode of the eighth diode are connected to the first terminal of the second rectifier unit; the anode of the ninth diode and the cathode of the tenth diode are connected to the second terminal of the second rectifier unit; and the anode of the eleventh diode and the cathode of the twelfth diode are connected to the third terminal of the second rectifier unit. The cathodes of the seventh diode, the ninth diode, and the eleventh diode are connected to the positive output terminal. The cathodes of the eighth diode, the tenth diode, and the twelfth diode are connected to the negative output terminal.

10. The three-phase LLC transformer current-sharing topology circuit according to any one of claims 1 to 7, characterized in that, The primary-side resonant circuit includes a first switching network, a second switching network, a third switching network, a first resonant unit, a second resonant unit, and a third resonant unit; The first terminal of the first switch network, the second switch network, and the third switch network are respectively connected to the positive input terminal, and the second terminal is respectively connected to the negative input terminal. The output terminal of the first switching network is connected to the first terminal of the primary winding of the first transformer via the first resonant unit; The output of the second switching network is connected to the first end of the primary winding of the second transformer via the second resonant unit; The output terminal of the third switching network is connected to the first terminal of the primary winding of the third transformer via the third resonant unit; The second end of the primary winding of the first transformer is connected to the second end of the primary winding of the second transformer and the second end of the primary winding of the third transformer.

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