Multi-transformer DC / DC circuit and current equalization system

Abstract

This application discloses a multi-transformer DC-DC circuit and system, related to the field of electronic power technology. The circuit includes two LLC circuits, each including a primary circuit, a secondary circuit, and m transformers, each including two primary windings and one secondary winding, where the first primary winding of the i-th transformer of the first LLC circuit is connected in series with the first primary winding of the i-th transformer of the second LLC circuit and connected to the corresponding primary circuit, and the second primary winding of the i-th transformer of the first LLC circuit is connected in series with the second primary winding of the i-th transformer of the second LLC circuit and connected to the corresponding primary circuit, and the secondary winding of each transformer is connected to the corresponding secondary circuit. This application naturally achieves power balance between the two power units, i.e., naturally achieves uniform flow, simplifies the control method, and improves circuit reliability.

Description

[Technical Field]

[0001] [Technical field] The present application relates to the field of electronic power technology, and more particularly to a multi-transformer DC / DC circuit and current equalization system. [Background technology]

[0002] [Background technology] Recently, electric vehicles have shown good prospects due to their environmental advantages compared to traditional vehicles. Although electric vehicles are powered by on-board power sources, the batteries have low energy storage capacity per unit weight, so users have no choice but to charge them frequently to operate them normally. Summary of the Invention [Means for solving the problem]

[0003] [DISCLOSURE OF THE INVENTION] The inventors have found that current charging technology cannot meet users' demands for charging speeds for electric vehicles.

[0004] Faster charging speeds mean higher charging power, leading to ever-increasing power requirements for charging modules in commercially available charging inlets. Traditional circuit designs typically meet higher power requirements through series / parallel circuit topology configurations. For example, Figure 1A illustrates a traditional parallel-connected topology of two LLC full-bridge circuits. However, due to the tolerances inherent in LLC parameters such as inductors and resonant capacitors, achieving uniform current flow when the two LLC circuits are operating requires separately detecting the output currents of the two LLCs and separately controlling the switching frequencies of the two LLCs. However, this results in mismatched switching frequencies.

[0005] 1B shows a traditional topology in which the primary circuits of two LLCs are connected in series and the secondary circuits are connected in parallel. The series-connected primary circuits allow the two LLC full-bridge circuits to operate at the same frequency, and the series-connected primary circuits ensure that the DC currents of the primary circuits are consistent. However, due to differences in the resonant parameters of the two LLC circuits, the power of the two LLC full-bridge circuits must be roughly balanced, meaning that the currents must be roughly balanced.

[0006] In order to solve at least one of the problems existing in the above-mentioned prior art, the present application provides a method for generating a power supply voltage from a power supply to a power supply, the method comprising: Each transformer includes two primary windings and a secondary winding disposed between the two primary windings; However, the two LLC circuits include a first LLC circuit and the second LLC circuit, a first primary winding of the ith transformer of the first LLC circuit and a first primary winding of the ith transformer of the second LLC circuit are connected in series and connected to the corresponding primary circuits, a second primary winding of the ith transformer of the first LLC circuit and a second primary winding of the ith transformer of the second LLC circuit are connected in series and connected to the corresponding primary circuits, a secondary winding of each transformer is connected to the corresponding secondary circuit, and 1≦i≦m, where i and m are all positive integers.

[0007] In one embodiment, the primary circuit includes a full bridge circuit, m=1, However, the primary circuit of the first LLC circuit includes a first transistor, a second transistor, a third transistor, and a fourth transistor, and the series circuit of the first transistor and the second transistor and the series circuit of the third transistor and the fourth transistor are connected in parallel; the primary circuit of the second LLC circuit includes a fifth transistor, a sixth transistor, a seventh transistor, and an eighth transistor, and the series circuit of the fifth transistor and the sixth transistor and the series circuit of the seventh transistor and the eighth transistor are connected in parallel; a first primary winding of a transformer of the first LLC circuit and a set of a resonant capacitor and a resonant inductance are connected in series and connected between a first transistor and a second transistor, and a first primary winding of a transformer of the second LLC circuit is connected between a third transistor and a fourth transistor; The second primary winding of the transformer of the first LLC circuit is connected between the seventh transistor and the eighth transistor, and the second primary winding of the transformer of the second LLC circuit and a set of a resonant capacitor and a resonant inductance are connected in series and connected between the fifth transistor and the sixth transistor.

[0008] In one embodiment, the secondary circuit includes a full-wave rectifier circuit; the secondary circuit of the first LLC circuit includes a first diode, a second diode, a third diode, and a fourth diode, and a series circuit of the first diode and the second diode and a series circuit of the third diode and the fourth diode are connected in parallel; the secondary circuit of the second LLC circuit includes a fifth diode, a sixth diode, a seventh diode, and an eighth diode, and a series circuit of the fifth diode and the sixth diode and a series circuit of the seventh diode and the eighth diode are connected in parallel; one end of a secondary winding of the transformer of the first LLC circuit is connected between the first diode and the second diode, and the other end is connected between the third diode and the fourth diode; One end of the secondary winding of the transformer of the second LLC circuit is connected between the fifth diode and the sixth diode, and the other end is connected between the seventh diode and the eighth diode.

[0009] In one embodiment, the secondary circuit includes a synchronous rectification circuit; a secondary circuit of the first LLC circuit includes a ninth transistor, a tenth transistor, an eleventh transistor, and a twelfth transistor, and a series circuit of the ninth transistor and the tenth transistor and a series circuit of the eleventh transistor and the twelfth transistor are connected in parallel; a secondary circuit of the second LLC circuit includes a thirteenth transistor, a fourteenth transistor, a fifteenth transistor, and a sixteenth transistor, and a series circuit of the thirteenth transistor and the fourteenth transistor and a series circuit of the fifteenth transistor and the sixteenth transistor are connected in parallel; one end of a secondary winding of the transformer of the first LLC circuit is connected between the ninth transistor and the tenth transistor, and the other end is connected between the eleventh transistor and the twelfth transistor; One end of the secondary winding of the transformer of the second LLC circuit is connected between the thirteenth transistor and the fourteenth transistor, and the other end is connected between the fifteenth transistor and the sixteenth transistor.

[0010] In one embodiment, the primary circuit includes a three-phase bridge circuit, m=3; However, the primary circuit of the first LLC circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor, and the series circuit of the first transistor and the second transistor, the series circuit of the third transistor and the fourth transistor, and the series circuit of the fifth transistor and the sixth transistor are connected in parallel; a primary circuit of the second LLC circuit includes a seventh transistor, an eighth transistor, a ninth transistor, a tenth transistor, an eleventh transistor, and a twelfth transistor, and the series circuit of the seventh transistor and the eighth transistor, the series circuit of the ninth transistor and the tenth transistor, and the series circuit of the eleventh transistor and the twelfth transistor are connected in parallel; a second primary winding of a first transformer of the first LLC circuit is connected between a first transistor and a second transistor, a first primary winding of a first transformer of the second LLC circuit is connected between a seventh transistor and an eighth transistor, and a first primary winding of a first transformer of the first LLC circuit is connected in series with a pair of a resonant capacitor and a resonant inductance and is connected to a second primary winding of a first transformer of a second LLC circuit via another pair of a resonant capacitor and a resonant inductance; a second primary winding of a second transformer of the first LLC circuit is connected between a third transistor and a fourth transistor, a first primary winding of a second transformer of the second LLC circuit is connected between a ninth transistor and a tenth transistor, and a first primary winding of a second transformer of the first LLC circuit is connected in series with a pair of a resonant capacitor and a resonant inductance and is connected to a second primary winding of a second transformer of a second LLC circuit via another pair of a resonant capacitor and a resonant inductance; The second primary winding of the third transformer of the first LLC circuit is connected between the fifth transistor and the sixth transistor, the first primary winding of the third transformer of the second LLC circuit is connected between the eleventh transistor and the twelfth transistor, and the first primary winding of the third transformer of the first LLC circuit is connected in series with a set of a resonant capacitor and a resonant inductance and is connected to the second primary winding of the third transformer of the second LLC circuit via another set of a resonant capacitor and a resonant inductance.

[0011] In one embodiment, the secondary circuit includes a full-wave rectifier circuit; the secondary circuit of the first LLC circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode, and the series circuit of the first diode and the second diode, the series circuit of the third diode and the fourth diode, and the series circuit of the fifth diode and the sixth diode are connected in parallel; the secondary circuit of the second LLC circuit includes a seventh diode, an eighth diode, a ninth diode, a tenth diode, an eleventh diode, and a twelfth diode, and the series circuit of the seventh diode and the eighth diode, the series circuit of the ninth diode and the tenth diode, and the series circuit of the eleventh diode and the twelfth diode are connected in parallel; a first end of a secondary winding of a first transformer in the first LLC circuit is connected between a first diode and a second diode, a first end of a secondary winding of a second transformer in the first LLC circuit is connected between a third diode and a fourth diode, a first end of a secondary winding of a third transformer in the first LLC circuit is connected between a fifth diode and a sixth diode, a second end of the secondary winding of the first transformer in the first LLC circuit and a second end of the secondary winding of the second transformer in the first LLC circuit are connected to a second end of the secondary winding of the third transformer in the first LLC circuit, A first end of a secondary winding of a first transformer in the second LLC circuit is connected between the seventh and eighth diodes, a first end of a secondary winding of a second transformer in the second LLC circuit is connected between the ninth and tenth diodes, a first end of a secondary winding of a third transformer in the second LLC circuit is connected between the eleventh and twelfth diodes, and a second end of the secondary winding of the first transformer in the second LLC circuit and a second end of the secondary winding of the second transformer in the second LLC circuit are connected to a second end of a secondary winding of a third transformer in the second LLC circuit.

[0012] In one embodiment, the secondary circuit includes a synchronous rectification circuit; the secondary circuit of the first LLC circuit includes a 13th transistor, a 14th transistor, a 15th transistor, a 16th transistor, a 17th transistor, and an 18th transistor, and the series circuit of the 13th transistor and the 14th transistor, the series circuit of the 15th transistor and the 16th transistor, and the series circuit of the 17th transistor and the 18th transistor are connected in parallel; the secondary circuit of the second LLC circuit includes a 19th transistor, a 20th transistor, a 21st transistor, a 22nd transistor, a 23rd transistor, and a 24th transistor, and the series circuit of the 19th transistor and the 20th transistor, the series circuit of the 21st transistor and the 22nd transistor, and the series circuit of the 23rd transistor and the 24th transistor are connected in parallel; a first end of a secondary winding of a first transformer in the first LLC circuit is connected between a thirteenth transistor and a fourteenth transistor, a first end of a secondary winding of a second transformer in the first LLC circuit is connected between a fifteenth transistor and a sixteenth transistor, a first end of a secondary winding of a third transformer in the first LLC circuit is connected between a seventeenth transistor and an eighteenth transistor, a second end of the secondary winding of the first transformer in the first LLC circuit and a second end of the secondary winding of the second transformer in the first LLC circuit are connected to a second end of a secondary winding of a third transformer in the first LLC circuit, A first end of a secondary winding of a first transformer of the second LLC circuit is connected between a 19th transistor and a 20th transistor, a first end of a secondary winding of a second transformer of the second LLC circuit is connected between a 21st transistor and a 22nd transistor, a first end of a secondary winding of a third transformer of the second LLC circuit is connected between a 23rd transistor and a 24th transistor, and a second end of the secondary winding of the first transformer of the second LLC circuit and a second end of the secondary winding of the second transformer of the second LLC circuit are connected to a second end of a secondary winding of a third transformer of the second LLC circuit.

[0013] In one embodiment, the resonant inductance of any of the multi-transformer DC-DC circuits is included in the leakage inductance of the transformer corresponding to the resonant inductance.

[0014] In one embodiment, the primary circuit of the first LLC circuit is connected in parallel with the primary circuit of the second LLC circuit.

[0015] In one embodiment, the primary circuit of the first LLC circuit is connected in series with the primary circuit of the second LLC circuit.

[0016] In one embodiment, the present application further provides a current equalization system using any of the multi-transformer DC / DC circuits described above.

[0017] The multi-transformer DCDC circuit and current equalization system of this application is premised on realizing the function of power parallel connection, and uses extremely simple synchronous control technology to naturally achieve power balance, i.e., uniform flow, between the two power units, thereby simplifying the control method and increasing the reliability of the circuit.

[0018] [Brief description of the drawing] In order to more clearly explain the embodiments of the present application or the technical solutions of the prior art, the drawings used in the embodiments or the prior art will be briefly described below. Of course, the drawings described below are only some of the embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without any inventive efforts. [Brief explanation of the drawings]

[0019] [Figure 1A] 1 is a prior art LLC circuit topology structure; [Figure 1B] 1 is a prior art LLC circuit topology structure; [Figure 2A] 1 is a structural schematic diagram of a transformer according to the present application; [Figure 2B] 1 is a structural schematic diagram of a transformer according to the present application; [Figure 3A] 1 shows the connection relationship between the primary winding and the secondary winding of each transformer according to the present application. [Figure 3B] 1 shows the connection relationship between the primary winding and the secondary winding of each transformer according to the present application. [Figure 4A] FIG. 1 is a schematic diagram illustrating a primary circuit and the connection relationship between the primary circuit and a transformer according to the present application. [Figure 4B] 4B is a schematic diagram of the drive pulses for each transistor in the primary circuit shown in FIG. 4A. [Figure 4C] FIG. 2 is a schematic diagram illustrating a secondary circuit and the connection relationship between the secondary circuit and a transformer according to the present application. [Figure 4D] FIG. 2 is another schematic diagram illustrating a secondary circuit and the connection relationship between the secondary circuit and a transformer according to the present application. [Figure 5A] FIG. 2 is another schematic diagram illustrating a primary circuit and the connection relationship between the primary circuit and a transformer according to the present application. [Figure 5B] 5B is a schematic diagram of the drive pulses for each transistor in the primary circuit shown in FIG. 5A. [Figure 5C] FIG. 2 is another schematic diagram illustrating a secondary circuit and the connection relationship between the secondary circuit and a transformer according to the present application. [Figure 5D] FIG. 2 is another schematic diagram illustrating a secondary circuit and the connection relationship between the secondary circuit and a transformer according to the present application. [Figure 6A] FIG. 4D is a circuit topology diagram including the circuit leakage inductance shown in FIG. 4C. [Figure 6B] FIG. 4E is a circuit topology diagram including the circuit leakage inductance shown in FIG. 4D. [Figure 6C] FIG. 5D is a circuit topology diagram including the circuit leakage inductance shown in FIG. 5C. [Figure 6D] FIG. 5E is a circuit topology diagram including the circuit leakage inductance shown in FIG. 5D. DETAILED DESCRIPTION OF THE INVENTION

[0020] BEST MODE FOR CARRYING OUT THE INVENTION In order to better understand the objectives, technical solutions and advantages of the embodiments of the present application, the embodiments of the present application will be described in more detail below with reference to the drawings. Here, the outline of the embodiments of the present application and the description thereof are for the purpose of interpreting the present application, and the present application is not limited thereto.

[0021] Incidentally, the multi-transformer DC-DC circuit of the present application can be applied to the field of electronic power technology, and can also be used in any field other than the field of electronic power technology, and the present application does not limit the field of application of the multi-transformer DC-DC circuit.

[0022] The present application relates to a multi-transformer DC-DC circuit, which includes two LLC circuits, each of which includes one primary circuit, one secondary circuit, and m transformers; Specifically, referring to the transformer structure shown in Figures 2A and 2B, each transformer includes a primary winding P1, a primary winding P2, and a secondary winding S1, with the secondary winding S1 disposed between the primary winding P1 and the primary winding P2. Figure 2A is a cross-sectional schematic diagram of the transformer, in which the primary winding P1, the secondary winding S1, and the primary winding P2 are wound around a frame F from left to right. The transformers shown in Figures 2A and 2B are characterized by the large distance between the two primary windings, resulting in a relatively low coupling coefficient between them, typically not exceeding 0.95. That is, the coupling coefficient between the two primary windings of the transformer according to the present application is 0.95 or less. Here, the coupling coefficient is defined as follows:

[0023]

number

[0024] where k is the coupling coefficient between the primary winding P1 and the primary winding P2, and L sc is the leakage inductance of the primary winding P1 side measured when the primary winding P2 is short-circuited, and L open is the inductance of the primary winding P1 side measured when the primary winding P2 is open.

[0025] The primary and secondary windings of each transformer in the two LLC circuits are connected in series with the first primary winding of the i-th transformer in the first LLC circuit and the first primary winding of the i-th transformer in the second LLC circuit, and the second primary winding of the i-th transformer in the first LLC circuit and the second primary winding of the i-th transformer in the second LLC circuit are connected in series with the second primary winding of the i-th transformer in the second LLC circuit, and the secondary winding of each transformer is connected to the corresponding secondary circuit, where 1≦i≦m, i and m are all positive integers. The number m of transformers in each LLC circuit is 1 or greater, and may be 1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 13, etc., by way of example only and not limitation.

[0026] For example, FIG. 3A shows the connections assuming one transformer for each LLC circuit, except that the first LLC circuit has only one transformer T 11 The second LLC circuit is provided with one transformer T 21 FIG. 3B shows the connections when three transformers are assumed to be provided for each LLC circuit, except that the first LLC circuit has only transformer T 11 , Trans T 12 and Trans T 13 The second LLC circuit is equipped with a transformer T 21 , Trans T 22 and Trans T 23 Three transformers are provided:

[0027] The primary circuits of two LLC circuits can be connected in parallel by connecting the primary circuits of the first LLC circuit and the second LLC circuit, or in series by connecting the primary circuits of the first LLC circuit and the second LLC circuit with DC input. When using a parallel connection of the primary circuits, the input voltage of the primary circuits can reach 650V-800V, but the current of each primary circuit is reduced by half compared to a series connection with DC input. This facilitates protection of the electronic components in the LLC circuits, prevents damage to the electronic components due to overcurrent, and improves efficiency. However, whether the primary circuits are connected in parallel or in series with DC input, both are applicable to this application, achieving natural, uniform current and synchronized control of the two LLC circuits.

[0028] The connection method of the secondary circuits in two LLC circuits can be the same as the connection method of the primary circuits. That is, when the primary circuits of two LLC circuits are connected in parallel, the secondary circuits of the two LLC circuits output DC and are connected in parallel; when the primary circuits of two LLC circuits input DC and are connected in series, the secondary circuits of the two LLC circuits output DC and are connected in series.

[0029] Meanwhile, the connection relationship between the transformer and the primary and secondary circuits in an LLC circuit varies depending on the type of the primary and secondary circuits, and should be consistent with the circuit characteristics of the primary and secondary circuits. This application provides several specific examples for explanation, and the following describes connection methods in which the primary circuits of two LLC circuits are connected in parallel and the secondary circuits are connected in parallel, but this application is not limited to this. At the same time, for convenience of explanation, the primary circuit of the first LLC circuit is defined as A1, the secondary circuit as B1, and the transformers are sequentially defined as T 11 , T 12 , T 13 ...T 1m The primary circuit of the second LLC circuit is defined as A2, the secondary circuit as B2, and the transformers are designated as T 21 , T 22 , T 23 ...T 2mwhere m is the number of transformers included in each LLC circuit and is a positive integer. The above definition applies to all of the following embodiments.

[0030] Example 1: The primary circuit includes a full-bridge circuit. At this time, each LLC circuit includes one transformer, i.e., m=1, to match the circuit characteristics of a full-bridge circuit.

[0031] 4A illustrates a circuit topology in which two full-bridge LLC circuits are connected in parallel, except that primary circuit A1 includes three parallel circuits: the first parallel circuit includes a capacitor C1, the second parallel circuit includes a series-connected first transistor Q1 and a series-connected second transistor Q2, and the third parallel circuit includes a series-connected third transistor Q3 and a series-connected fourth transistor Q4. Primary circuit A2 is similar in structure to primary circuit A1 and also includes three parallel circuits: the first parallel circuit includes a capacitor C2, the second parallel circuit includes a series-connected fifth transistor Q5 and a series-connected sixth transistor Q6, and the third parallel circuit includes a series-connected seventh transistor Q7 and an series-connected eighth transistor Q8.

[0032] Transformer T 11 The first primary winding P 111 One end of the transformer T 21 The first primary winding P 211 The other end is connected in series to a pair of resonant capacitors C 11 and resonant inductance L 11 and connected in series between the first transistor Q1 and the second transistor Q2, and a transformer T 21 The first primary winding P 211 The other end is connected between the third transistor Q3 and the fourth transistor Q4.

[0033] Similarly, transformer T 11 The second primary winding P 112 One end of the transformer T 21 The second primary winding P212 The other end is connected between the seventh transistor Q7 and the eighth transistor Q8. 21 The second primary winding P 212 The other end of the 21 and resonant inductance L 21 and connected in series between the fifth transistor Q5 and the sixth transistor Q6.

[0034] Figure 4B is a schematic diagram of the driving pulses of each transistor in the primary circuit shown in Figure 4A. Referring to Figure 4B, the first transistor Q1, the fourth transistor Q4, the sixth transistor Q6, and the seventh transistor Q7 are simultaneously turned on, and the second transistor Q2, the third transistor Q3, the fifth transistor Q5, and the eighth transistor Q8 are simultaneously turned on.

[0035] The transformer including two primary windings shown in Example 1 naturally realizes uniform current flow between the two full-bridge LLCs through the series connection between the upper and lower full-bridges, and the two full-bridge circuits have the same control frequency. Under normal operating conditions (except for special conditions such as startup), the control signals of the first transistor Q1, the fourth transistor Q4, the sixth transistor Q6, and the seventh transistor Q7 are the same, and the control signals of the second transistor Q2, the third transistor Q3, the fifth transistor Q5, and the eighth transistor Q8 are the same. These two control signals complement each other and add a certain dead time (the dead time is predetermined). This greatly simplifies the control lines and control algorithm, and avoids the generation of an oscillating frequency (i.e., the frequency difference between the two is variable) and the generation of ripple current and ripple voltage due to the asynchronous control method of the circuit topology shown in Figure 1A.

[0036] When the primary circuit is configured as in Example 1, the secondary circuit can refer to Examples 2 and 3.

[0037] Example 2: The secondary circuit includes a full-wave rectifier circuit made up of diodes. 4C, secondary circuit B1 includes three parallel-connected circuits, the first of which includes a capacitor C3, the second of which includes a series-connected first diode D1 and a series-connected second diode D2, and the third of which includes a series-connected third diode D3 and a series-connected fourth diode D4. Secondary circuit B2 is similar in structure to secondary circuit B1 and also includes three parallel-connected circuits, the first of which includes a capacitor C4, the second of which includes a series-connected fifth diode D5 and a series-connected sixth diode D6, and the third of which includes a series-connected seventh diode D7 and an eighth diode D8.

[0038] Transformer T 11 Secondary winding S 11 One end of the diode D1 is connected between the first diode D1 and the second diode D2, and the other end of the diode D2 is connected between the third diode D3 and the fourth diode D4.

[0039] Similarly, transformer T 21 Secondary winding S 21 One end of the diode D1 is connected between the fifth diode D5 and the sixth diode D6, and the other end of the diode D1 is connected between the seventh diode D7 and the eighth diode D8.

[0040] Example 3: The secondary circuit includes a synchronous rectifier circuit made up of transistors. As shown in FIG. 4D, the secondary circuit B1 includes three parallel-connected circuits, the first of which includes a capacitor C3, and the second of which includes a ninth transistor Q9 and a tenth transistor Q10 connected in series. 10 The third parallel connection circuit is provided with a series-connected eleventh transistor Q 11 and the 12th transistor Q 12 The secondary circuit B2 is similar in structure to the secondary circuit B1 and similarly includes three parallel-connected circuits, the first of which includes a capacitor C4, and the second of which includes a series-connected thirteenth transistor Q 13and the 14th transistor Q 14 The third parallel circuit is provided with a series-connected 15th transistor Q 15 and the 16th transistor Q 16 is provided.

[0041] Transformer T 11 Secondary winding S 11 One end of the ninth transistor Q9 and the tenth transistor Q 10 and the other end is connected to the eleventh transistor Q 11 and the 12th transistor Q 12 is connected between

[0042] Similarly, transformer T 21 Secondary winding S 21 One end of the 13th transistor Q 13 and the 14th transistor Q 14 and the other end is connected between the 15th transistor Q 15 and the 16th transistor Q 16 is connected between

[0043] Example 4: The primary circuit includes a three-phase bridge circuit. At this time, in order to match the circuit characteristics of the three-phase bridge circuit, each LLC circuit is equipped with three transformers, i.e., m=3. The first LLC circuit is equipped with transformer T 11 , Trans T 12 and Trans T 13 The second LLC circuit includes a transformer T 21 , Trans T 22 and Trans T 23 Includes:

[0044] 5A illustrates a circuit topology in which two three-bridge LLC circuits are connected in parallel, except that primary circuit A1 includes four parallel circuits, the first of which includes a capacitor C1, the second of which includes a series-connected first transistor Q1 and a series-connected second transistor Q2, the third of which includes a series-connected third transistor Q3 and a series-connected fourth transistor Q4, and the fourth of which includes a series-connected fifth transistor Q5 and a series-connected sixth transistor Q6. Primary circuit A2 is similar in structure to primary circuit A1 and also includes four parallel circuits, the first of which includes a capacitor C2, the second of which includes a series-connected seventh transistor Q7 and a series-connected eighth transistor Q8, and the third of which includes a series-connected ninth transistor Q9 and a series-connected tenth transistor Q9. 10 The fourth parallel connection circuit is provided with a series-connected eleventh transistor Q 11 and the 12th transistor Q 12 is provided.

[0045] Transformer T 11 The second primary winding P 112 One end of the transistor Q1 is connected between the first transistor Q1 and the second transistor Q2, and the other end of the transistor T 21 The second primary winding P 212 is connected to one end of the primary winding P 212 The other end of the 21 and the resonant inductance L 21 are connected in series to the common node. 21 The first primary winding P 211 One end of the transistor Q7 is connected to the seventh transistor Q7 and the eighth transistor Q8, and the other end of the transistor T 11 The first primary winding P 111 is connected to one end of the primary winding P 111 The other end of the 11 and the resonant inductance L 11 and connected in series to a common node, 212 It is connected to.

[0046] Similarly, transformer T 12 The second primary winding P 122 One end of the transformer T is connected between the first transistor Q3 and the fourth transistor Q4. 22 The second primary winding P 222 is connected to one end of the primary winding P 222 The other end of the 22 and resonant inductance L 22 are connected in series to the common node. 22 The first primary winding P 221 One end of the ninth transistor Q9 and the tenth transistor Q 10 and the other end is connected to transformer T 12 The first primary winding P 121 is connected to one end of the primary winding P 121 The other end of the 12 and resonant inductance L 12 and connected in series to a common node, 222 It is connected to.

[0047] Transformer T 13 The second primary winding P 132 One end of the transistor Q1 is connected between the fifth transistor Q5 and the sixth transistor Q6, and the other end of the transistor T 232 The second primary winding P 232 is connected to one end of the primary winding P 232 The other end of the 23 and the resonant inductance L 23 are connected in series to the common node. 23 The first primary winding P 221 One end of the eleventh transistor Q 11 and the 12th transistor Q 12 and the other end is connected to transformer T 13 The first primary winding P 131 is connected to one end of the primary winding P 131 The other end of the 13 and resonant inductance L 13and connected in series to a common node, 232 It is connected to.

[0048] 5B is a schematic diagram of the driving pulses of each transistor in the primary circuit shown in FIG. 5A. Referring to FIG. 5B, the primary circuit is controlled by three driving signals with a phase difference of 120°. However, the first transistor Q1 and the eighth transistor Q8 in the primary circuit are simultaneously turned on, the second transistor Q2 and the seventh transistor Q7 are simultaneously turned on, and the third transistor Q3 and the tenth transistor Q 10 are simultaneously turned on, the fourth transistor Q4 and the ninth transistor Q9 are simultaneously turned on, and the fifth transistor Q5 and the twelfth transistor Q 12 are simultaneously turned on, and the sixth transistor Q6 and the eleventh transistor Q 11 are simultaneously conducted.

[0049] When the primary circuit is configured as shown in Example 3, the secondary circuit can refer to Examples 5 and 6.

[0050] <<Embodiment 5>> The secondary circuit includes a full-wave rectifier circuit made up of diodes. 5C, secondary circuit B1 includes four parallel-connected circuits, the first of which includes a capacitor C3, the second of which includes a series-connected first diode D1 and a series-connected second diode D2, the third of which includes a series-connected third diode D3 and a series-connected fourth diode D4, and the fourth of which includes a series-connected fifth diode D5 and a series-connected sixth diode D6. Secondary circuit B2 is similar in structure to secondary circuit B1 and similarly includes four parallel-connected circuits, the first of which includes a capacitor C4, the second of which includes a series-connected seventh diode D7 and a series-connected eighth diode D8, and the third of which includes a series-connected ninth diode D9 and a series-connected tenth diode D10. 10 The fourth parallel connection circuit is provided with a series-connected eleventh diode D 11 and the 12th diode D12 is provided.

[0051] Transformer T 11 Secondary winding S 11 One end of the transformer T is connected between the first diode D1 and the second diode D2, and the other end of the transformer T is connected to the first shared node. 12 Secondary winding S 12 One end of the transformer T is connected between the third diode D3 and the fourth diode D4, and the other end is connected to the first shared node. 13 Secondary winding S 13 One end of the secondary winding S is connected between the fifth diode D5 and the sixth diode D6, and the other end is connected to the first shared node. 11 , secondary winding S 12 and the secondary winding S 13 However, one end of each of these is connected to the same shared node.

[0052] Similarly, transformer T 21 Secondary winding S 21 One end of the transformer T is connected between the seventh diode D7 and the eighth diode D8, and the other end is connected to the second shared node. 22 Secondary winding S 22 One end of the ninth diode D9 and the tenth diode D 10 and the other end is connected to the second shared node. 23 Secondary winding S 23 One end of the 11th diode D 11 and the 12th diode D 12 and the other end is connected to the second shared node. 21 , secondary winding S 22 and the secondary winding S 23 However, one end of each of these is connected to the same shared node and communicates with each other.

[0053] Incidentally, the first shared node and the second shared node are different nodes. Example 6: The secondary circuit includes a synchronous rectifier circuit made up of transistors.

[0054] As shown in FIG. 5D, the secondary circuit B1 includes four parallel-connected circuits, the first of which includes a capacitor C3, and the second of which includes a series-connected thirteenth transistor Q 13 and the 14th transistor Q 14 The third parallel circuit is provided with a series-connected 15th transistor Q 15 and the 16th transistor Q 16 The fourth parallel connection circuit is provided with a seventeenth transistor Q 17 and the 18th transistor Q 18 The secondary circuit B2 is similar in structure to the secondary circuit B1 and also includes four parallel-connected circuits, the first of which includes a capacitor C4, and the second of which includes a series-connected 19th transistor Q 19 and the 20th transistor Q 20 The third parallel connection circuit is provided with a 21st transistor Q 21 and the 22nd transistor Q 22 The fourth parallel connection circuit is provided with a 23rd transistor Q 23 and the 24th transistor Q 24 is provided.

[0055] Transformer T 11 Secondary winding S 11 One end of the 13th transistor Q 13 and the 14th transistor Q 14 and the other end is connected to the first shared node. 12 Secondary winding S 12 One end of the 15th transistor Q 15 and the 16th transistor Q 16 and the other end is connected to the first shared node. 13 Secondary winding S 13 One end of the 17th transistor Q 17 and the 18th transistor Q 18 and the other end is connected to the first shared node.11 , secondary winding S 12 and the secondary winding S 13 However, one end of each of these is connected to the same shared node and communicates with each other.

[0056] Similarly, transformer T 21 Secondary winding S 21 One end of the 19th transistor Q 19 and the 20th transistor Q 20 and the other end is connected to the second shared node. 22 Secondary winding S 22 One end of the 21st transistor Q 21 and the 22nd transistor Q 22 and the other end is connected to the second shared node. 23 Secondary winding S 23 One end of the 23rd transistor Q 23 and the 24th transistor Q 24 and the other end is connected to the second shared node. 21 , secondary winding S 22 and the secondary winding S 23 However, one end of each of these is connected to the same shared node, so that they are in communication with each other.

[0057] Incidentally, the first shared node and the second shared node are different nodes. The above-mentioned Examples 1 to 6 respectively exemplify a number of different primary circuits, secondary circuits, and the connection relationships between them and transformers, but compared with the full-wave rectifier circuits of Examples 2 and 5, the synchronous rectifier circuits of Examples 3 and 6 can achieve bidirectional circuit operation. In addition to the above-mentioned examples, those skilled in the art can connect the structure in which the primary circuits of the transformers of the present application are connected in series to other types of circuits based on the principles of the present application, provided that the circuit characteristics are satisfied, but the present application is not limited thereto.

[0058] In one embodiment, the leakage inductance of the transformer is used as the resonant inductance, i.e., any resonant inductance mentioned in the above embodiment may be included in the leakage inductance of the transformer corresponding to the resonant inductance. If the leakage inductance of the transformer is of an appropriate size, the leakage inductance can function as an inductance, and in this case, there is no need to provide a separate resonant inductance in the circuit.

[0059] Specifically, as described above, the transformer used in the present application includes two primary windings and one secondary winding. The secondary winding is located between the two primary windings, and the distance between the two primary windings is large, reducing the coupling coefficient between the two primary windings. From the definition of coupling coefficient, a low coupling coefficient means a large leakage inductance of the transformer. Therefore, in this embodiment, to simplify the circuit, the present application adjusts the leakage inductance of the transformer to an appropriate size to replace the resonant inductance in the circuit, thereby allowing the resonant inductance to be included. If the leakage inductance of the transformer is not large, an inductance can be connected in series external to the transformer, and the series-connected inductance and the transformer leakage inductance can jointly function as the resonant inductance. Specifically, referring to FIGS. 6A to 6D, FIG. 6A is a circuit topology diagram including the circuit leakage inductance shown in FIG. 4C, FIG. 6B is a circuit topology diagram including the circuit leakage inductance shown in FIG. 4D, FIG. 6C is a circuit topology diagram including the circuit leakage inductance shown in FIG. 5C, and FIG. 6D is a circuit topology diagram including the circuit leakage inductance shown in FIG. 5D.

[0060] In one embodiment, the present application provides a current equalization system, which uses any multi-transformer DC-DC circuit according to the present application. Other circuit structures of the current equalization system may vary according to requirements, and the present application does not specifically limit other circuit structures of the current equalization system.

[0061] The multi-transformer DCDC circuit and current equalization system of the present application is premised on realizing the function of parallel connection of power, and uses extremely simple synchronous control technology to simultaneously and naturally achieve power balance between the two power units, that is, to naturally achieve uniform flow, thereby simplifying the control method and increasing the reliability of the circuit.

[0062] The above specific examples have explained in detail the objectives, technical solutions and beneficial effects of the present application, but these are merely specific examples of the present application, and the protection scope of the present application is not limited thereto. It should be understood that all amendments, equivalent replacements, improvements, etc. made within the scope that does not deviate from the spirit and principles of the present application fall within the protection scope of the present application.

Claims

1. A multi-transformer DC / DC circuit, two LLC circuits, each LLC circuit including one primary circuit, one secondary circuit, and m transformers; Each of the transformers includes two primary windings and a secondary winding disposed between the two primary windings, the two LLC circuits include a first LLC circuit and a second LLC circuit, a first primary winding of an i-th transformer of the first LLC circuit and a first primary winding of an i-th transformer of the second LLC circuit are connected in series and connected to corresponding primary circuits, a second primary winding of an i-th transformer of the first LLC circuit and a second primary winding of an i-th transformer of the second LLC circuit are connected in series and connected to corresponding primary circuits, a secondary winding of each transformer is connected to a corresponding secondary circuit, 1≦i≦m, where i and m are both positive integers.

2. the primary circuit includes a full bridge circuit, m is 1, However, the primary circuit of the first LLC circuit includes a first transistor, a second transistor, a third transistor, and a fourth transistor, and the series circuit of the first transistor and the second transistor and the series circuit of the third transistor and the fourth transistor are connected in parallel; the primary circuit of the second LLC circuit includes a fifth transistor, a sixth transistor, a seventh transistor, and an eighth transistor, and the series circuit of the fifth transistor and the sixth transistor and the series circuit of the seventh transistor and the eighth transistor are connected in parallel; a first primary winding of a transformer of the first LLC circuit is connected in series with a pair of a resonant capacitor and a resonant inductance and is connected between a first transistor and a second transistor, and a first primary winding of a transformer of the second LLC circuit is connected between a third transistor and a fourth transistor; 2. The multi-transformer DC-DC circuit of claim 1, wherein a second primary winding of the transformer of the first LLC circuit is connected between the seventh transistor and the eighth transistor, and a second primary winding of the transformer of the second LLC circuit is connected in series with a pair of a resonant capacitor and a resonant inductance and connected between the fifth transistor and the sixth transistor.

3. the secondary circuit includes a full-wave rectifier circuit; the secondary circuit of the first LLC circuit includes a first diode, a second diode, a third diode, and a fourth diode, and a series circuit of the first diode and the second diode and a series circuit of the third diode and the fourth diode are connected in parallel; the secondary circuit of the second LLC circuit includes a fifth diode, a sixth diode, a seventh diode, and an eighth diode, and a series circuit of the fifth diode and the sixth diode and a series circuit of the seventh diode and the eighth diode are connected in parallel; one end of a secondary winding of the transformer of the first LLC circuit is connected between the first diode and the second diode, and the other end is connected between the third diode and the fourth diode; 3. The multi-transformer DC-DC circuit according to claim 2, wherein one end of a secondary winding of the transformer of the second LLC circuit is connected between the fifth diode and the sixth diode, and the other end is connected between the seventh diode and the eighth diode.

4. the secondary circuit includes a synchronous rectification circuit; a secondary circuit of the first LLC circuit includes a ninth transistor, a tenth transistor, an eleventh transistor, and a twelfth transistor, and a series circuit of the ninth transistor and the tenth transistor and a series circuit of the eleventh transistor and the twelfth transistor are connected in parallel; a secondary circuit of the second LLC circuit includes a thirteenth transistor, a fourteenth transistor, a fifteenth transistor, and a sixteenth transistor, and a series circuit of the thirteenth transistor and the fourteenth transistor and a series circuit of the fifteenth transistor and the sixteenth transistor are connected in parallel; one end of a secondary winding of the transformer of the first LLC circuit is connected between the ninth transistor and the tenth transistor, and the other end is connected between the eleventh transistor and the twelfth transistor; 3. The multi-transformer DC-DC circuit according to claim 2, wherein one end of a secondary winding of the transformer of the second LLC circuit is connected between the thirteenth transistor and the fourteenth transistor, and the other end is connected between the fifteenth transistor and the sixteenth transistor.

5. the primary circuit includes a three-phase bridge circuit, m is 3; a primary circuit of the first LLC circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor, and a series circuit of the first transistor and the second transistor, a series circuit of the third transistor and the fourth transistor, and a series circuit of the fifth transistor and the sixth transistor are connected in parallel; a primary circuit of the second LLC circuit includes a seventh transistor, an eighth transistor, a ninth transistor, a tenth transistor, an eleventh transistor, and a twelfth transistor, and the series circuit of the seventh transistor and the eighth transistor, the series circuit of the ninth transistor and the tenth transistor, and the series circuit of the eleventh transistor and the twelfth transistor are connected in parallel; a second primary winding of a first transformer of the first LLC circuit is connected between a first transistor and a second transistor, a first primary winding of a first transformer of the second LLC circuit is connected between a seventh transistor and an eighth transistor, and a first primary winding of a first transformer of the first LLC circuit is connected in series with a pair of a resonant capacitor and a resonant inductance and is connected to a second primary winding of a first transformer of a second LLC circuit via another pair of a resonant capacitor and a resonant inductance; a second primary winding of a second transformer of the first LLC circuit is connected between a third transistor and a fourth transistor, a first primary winding of a second transformer of the second LLC circuit is connected between a ninth transistor and a tenth transistor, and a first primary winding of a second transformer of the first LLC circuit is connected in series with a pair of a resonant capacitor and a resonant inductance and is connected to a second primary winding of a second transformer of a second LLC circuit via another pair of a resonant capacitor and a resonant inductance; 2. The multi-transformer DC-DC circuit according to claim 1, wherein the second primary winding of the third transformer of the first LLC circuit is connected between the fifth transistor and the sixth transistor, the first primary winding of the third transformer of the second LLC circuit is connected between the eleventh transistor and the twelfth transistor, and the first primary winding of the third transformer of the first LLC circuit is connected in series with a pair of a resonant capacitor and a resonant inductance and is connected to the second primary winding of the third transformer of the second LLC circuit via another pair of a resonant capacitor and a resonant inductance.

6. the secondary circuit includes a full-wave rectifier circuit; the secondary circuit of the first LLC circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode, and the series circuit of the first diode and the second diode, the series circuit of the third diode and the fourth diode, and the series circuit of the fifth diode and the sixth diode are connected in parallel; the secondary circuit of the second LLC circuit includes a seventh diode, an eighth diode, a ninth diode, a tenth diode, an eleventh diode, and a twelfth diode, and the series circuit of the seventh diode and the eighth diode, the series circuit of the ninth diode and the tenth diode, and the series circuit of the eleventh diode and the twelfth diode are connected in parallel; a first end of a secondary winding of a first transformer in the first LLC circuit is connected between a first diode and a second diode, a first end of a secondary winding of a second transformer in the first LLC circuit is connected between a third diode and a fourth diode, a first end of a secondary winding of a third transformer in the first LLC circuit is connected between a fifth diode and a sixth diode, a second end of the secondary winding of the first transformer in the first LLC circuit and a second end of the secondary winding of the second transformer in the first LLC circuit are connected to a second end of the secondary winding of the third transformer in the first LLC circuit, 6. The multi-transformer DC-DC circuit according to claim 5, wherein a first end of a secondary winding of a first transformer of the second LLC circuit is connected between seventh and eighth diodes, a first end of a secondary winding of a second transformer of the second LLC circuit is connected between ninth and tenth diodes, a first end of a secondary winding of a third transformer of the second LLC circuit is connected between eleventh and twelfth diodes, and a second end of the secondary winding of the first transformer of the second LLC circuit and a second end of the secondary winding of the second transformer of the second LLC circuit are connected to a second end of a secondary winding of a third transformer of the second LLC circuit.

7. the secondary circuit includes a synchronous rectification circuit; the secondary circuit of the first LLC circuit includes a 13th transistor, a 14th transistor, a 15th transistor, a 16th transistor, a 17th transistor, and an 18th transistor, and the series circuit of the 13th transistor and the 14th transistor, the series circuit of the 15th transistor and the 16th transistor, and the series circuit of the 17th transistor and the 18th transistor are connected in parallel; the secondary circuit of the second LLC circuit includes a 19th transistor, a 20th transistor, a 21st transistor, a 22nd transistor, a 23rd transistor, and a 24th transistor, and the series circuit of the 19th transistor and the 20th transistor, the series circuit of the 21st transistor and the 22nd transistor, and the series circuit of the 23rd transistor and the 24th transistor are connected in parallel; a first end of a secondary winding of a first transformer in the first LLC circuit is connected between a thirteenth transistor and a fourteenth transistor, a first end of a secondary winding of a second transformer in the first LLC circuit is connected between a fifteenth transistor and a sixteenth transistor, a first end of a secondary winding of a third transformer in the first LLC circuit is connected between a seventeenth transistor and an eighteenth transistor, a second end of the secondary winding of the first transformer in the first LLC circuit and a second end of the secondary winding of the second transformer in the first LLC circuit are connected to a second end of a secondary winding of a third transformer in the first LLC circuit, 6. The multi-transformer DC-DC circuit of claim 5, wherein a first end of a secondary winding of a first transformer of the second LLC circuit is connected between a 19th transistor and a 20th transistor, a first end of a secondary winding of a second transformer of the second LLC circuit is connected between a 21st transistor and a 22nd transistor, a first end of a secondary winding of a third transformer of the second LLC circuit is connected between a 23rd transistor and a 24th transistor, and a second end of the secondary winding of the first transformer of the second LLC circuit and a second end of the secondary winding of the second transformer of the second LLC circuit are connected to a second end of a secondary winding of a third transformer of the second LLC circuit.

8. The multi-transformer DC-DC circuit according to any one of claims 2 to 7, characterized in that any resonant inductance of the multi-transformer DC-DC circuit is included in the leakage inductance of the transformer corresponding to that resonant inductance.

9. 8. The multi-transformer DC-DC circuit according to claim 1, wherein the primary circuit of the first LLC circuit is connected in parallel with the primary circuit of the second LLC circuit.

10. 8. The multi-transformer DC-DC circuit according to claim 1, wherein the primary circuit of the first LLC circuit is connected in series with the primary circuit of the second LLC circuit.

11. A current equalization system comprising a multi-transformer DC / DC circuit according to any one of claims 1 to 10.

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