Multi-port interconnection module and system

Abstract

The present application belongs to the technical field of power electronics. Disclosed are a multi-port interconnection module and system. The multi-port interconnection module comprises: a coupling transformer, which comprises a plurality of first windings and a plurality of second windings, wherein the first windings and the second windings are distributed on different sides of the coupling transformer; a plurality of first DC-AC converters, wherein alternating-current sides of the plurality of first DC-AC converters are correspondingly connected to the plurality of first windings; and a plurality of second AC-DC converters, wherein alternating-current sides of the plurality of second AC-DC converters are correspondingly connected to the plurality of second windings, and the plurality of second AC-DC converters at least involve two different topological structures.

Description

Multi-port interconnect modules and systems

[0001] Cross-references

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on November 30, 2023, with application number 202311653926.6 and application name “Multi-port Interconnection Module and System”. The entire contents of the application are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of power electronics technology, and in particular to a multi-port interconnection module and system. Background Art

[0004] With the development of power systems, AC / DC hybrid power supply technology is considered to be the development direction. Traditional AC / DC hybrid technology uses a multi-port transformer to connect multiple H-bridge modules to build an AC / DC hybrid module. However, this solution requires more modules when implementing different levels of DC and is more expensive. Summary of the Invention

[0005] An embodiment of the present application provides a multi-port interconnection module, which includes: a coupling transformer, the coupling transformer including multiple first windings and multiple second windings, the first windings and the second windings being distributed on different sides of the coupling transformer; multiple first DC-AC converters, the AC sides of the multiple first DC-AC converters being correspondingly connected to the multiple first windings; and multiple second AC-DC converters, the AC sides of the multiple second AC-DC converters being correspondingly connected to the multiple second windings, the multiple second AC-DC converters including at least two different topological structures.

[0006] An embodiment of the present application also provides a multi-port interconnection system, comprising at least three multi-port interconnection modules as described in the above embodiment; the multi-port interconnection module comprises a plurality of first AC-DC converters, and the plurality of first AC-DC converters are correspondingly connected to the plurality of first DC-AC converters; the AC sides of at least two of the first AC-DC converters in the multi-port interconnection module are connected in series, and the neutral terminals of the AC sides of at least three of the multi-port interconnection modules are connected in parallel for accessing three-phase AC.

[0007] An embodiment of the present application also provides a multi-port interconnection system, comprising at least two multi-port interconnection modules as described in the above embodiment; the multi-port interconnection module comprises a plurality of first AC-DC converters, and the plurality of first AC-DC converters are correspondingly connected to the plurality of first DC-AC converters; the AC sides of at least two of the first AC-DC converters in the multi-port interconnection module are connected in series; and the AC sides of at least two of the multi-port interconnection modules are connected in series for accessing single-phase high-voltage AC. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG1 is a schematic structural diagram of an AC / DC interconnection module according to an embodiment of the present application;

[0009] FIG2 is a topological structure of a second AC-DC converter in an AC-DC interconnection module according to an embodiment of the present application;

[0010] FIG3 is another topology structure of the second AC-DC converter in the AC-DC interconnection module according to an embodiment of the present application;

[0011] FIG4 is a schematic structural diagram of an embodiment of an AC / DC interconnection module according to an embodiment of the present application;

[0012] FIG5 is a schematic diagram of the circuit structure of an embodiment of the AC / DC interconnection module shown in FIG4 ;

[0013] FIG6 is a waveform diagram of the switch tube in the AC / DC interconnection module shown in FIG5 ;

[0014] FIG7 is a structural diagram of an embodiment of an AC / DC interconnection module according to an embodiment of the present application;

[0015] FIG8 is a schematic diagram of the circuit structure of an embodiment of the AC / DC interconnection module shown in FIG7 ;

[0016] FIG9 is a schematic structural diagram of an embodiment of an AC / DC interconnection module according to an embodiment of the present application;

[0017] FIG10 is a schematic diagram of the circuit structure of an embodiment of the AC / DC interconnection module shown in FIG9 ;

[0018] FIG11 is a schematic structural diagram of an embodiment of an AC / DC interconnection module according to an embodiment of the present application;

[0019] FIG12 is a schematic diagram of the circuit structure of an embodiment of the AC / DC interconnection module shown in FIG11 ;

[0020] FIG13 is a schematic structural diagram of an embodiment of an AC / DC interconnection system according to an embodiment of the present application;

[0021] FIG14 is a structural diagram of another embodiment of the AC / DC interconnection system involved in the embodiment of the present application.

[0022] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0023] It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0024] With the development of the Energy Internet, AC / DC fusion interconnection has become a critical issue. This requires connecting electrical energy of different voltage levels and forms, and different ports must adopt either isolated or non-isolated structures depending on the situation. For example, in household or industrial scenarios, both AC power (such as motors and household appliances) and DC power (such as electric vehicles) are required. Therefore, it is necessary to design a circuit structure that can integrate AC and DC. This circuit structure can input AC or DC power and output DC and AC power of different voltage levels.

[0025] At present, the relevant technology generally adopts the common bus method to realize the above-mentioned circuit structure, that is, to construct an AC bus or a DC bus, and each port is connected using a different topology. For example: in a circuit structure, an AC bus is used to provide AC power, multiple transformers are connected in parallel on the AC bus, and rectifiers (such as H-bridge rectifiers) are connected to some transformers to convert AC power into DC power output. It is also possible to output different levels of DC power by connecting multiple rectifiers in series or in parallel; rectifiers and inverters are connected in series on some transformers to output AC power, and it is also possible to support the input of different levels of AC power by connecting multiple inverters (such as H-bridge inverters) in series or in parallel. In this way, only one type of AC power needs to be input in the entire circuit structure, and different levels of AC and DC power can be output, realizing AC / DC fusion.

[0026] However, the aforementioned circuit structure, which uses busbars and multiple transformers for connection, suffers from large size, high cost, multiple conversion steps, and low conversion efficiency. Therefore, a circuit structure that is compatible with AC and DC power at multiple voltage levels is needed to reduce size, cost, conversion steps, and improve conversion efficiency.

[0027] In the related art, a multi-port transformer is used to connect multiple H-bridge modules to construct an AC / DC hybrid module. Although this circuit structure does not require a busbar and multiple transformers, it can reduce the volume and reduce the conversion links. However, when achieving different levels of DC output, the H-bridge modules need to be connected in series or connected to different levels of DC modules to output different levels of DC voltage. This requires more modules and is more expensive.

[0028] To this end, an embodiment of the present application provides a multi-port interconnection module, including: a coupling transformer, the coupling transformer including multiple first windings and multiple second windings, the first windings and the second windings are distributed on different sides of the coupling transformer; multiple first DC-AC converters, the AC sides of the multiple first DC-AC converters are correspondingly connected to the multiple first windings; multiple second AC-DC converters, the AC sides of the multiple second AC-DC converters are correspondingly connected to the multiple second windings, and the multiple second AC-DC converters include at least two different topological structures.

[0029] The coupling transformer is a multi-port transformer with multiple primary and secondary windings. In this embodiment, when the first winding is the primary winding, the second winding is the secondary winding; when the first winding is the secondary winding, the second winding is the primary winding. As shown in Figure 1, the winding on the left side of the coupling transformer is the first winding, and the winding on the right side of the coupling transformer is the second winding.

[0030] For example, the coupling transformer is a high-frequency transformer, which is a power transformer with an operating frequency exceeding the medium frequency (10kHz). High-frequency transformers can be divided into several grades based on the operating frequency: 10kHz-50kHz, 50kHz-100kHz, 100kHz-500kHz, 500kHz-1MHz, and above 10MHz.

[0031] Exemplary topologies include a three-level topology, a full-wave rectifier topology, a half-bridge rectifier topology, a full-bridge rectifier topology, and a voltage doubler rectifier topology. In this embodiment, the second winding of the coupling transformer is connected to at least two different topologies to achieve different levels of DC voltage. In practical applications, the second winding of the coupling transformer can also be connected to three or more different topologies.

[0032] The embodiment of the present application discloses a multi-port interconnection module, which couples and connects multiple first DC-AC converters and multiple second AC-DC converters through a coupling transformer to form a multi-port DC-DC interconnection module. The second AC-DC converter includes two different topological structures. Therefore, the multi-port interconnection module in the embodiment of the present application can output different levels of DC power. Compared with connecting multiple H-bridge modules with a multi-port transformer and connecting multiple H-bridge modules in series to output different levels of DC voltage, the embodiment of the present application requires fewer modules to achieve different levels of DC output, has a simple structure, and is relatively low in cost. In addition, the embodiment of the present application uses a coupling transformer to connect multiple first DC-AC converters and multiple second AC-DC converters to achieve electrical isolation of multiple conversion modules.

[0033] In one embodiment, the two different topologies include: a single-phase three-level topology and a center-tapped full-wave rectifier topology.

[0034] The single-phase three-level topology can be an I-type three-level topology as shown in FIG2 , or a T-type three-level topology or an active neutral point clamped (ANPC) three-level topology; the center-tapped full-wave rectifier topology is shown in FIG3 .

[0035] In this embodiment, when the input voltage is the same, the voltage output by the single-phase three-level topology is approximately twice that of the center-tapped full-wave rectifier topology. When the input voltage is different, the difference between the voltage output by the single-phase three-level topology and the voltage output by the center-tapped full-wave rectifier topology varies. In this embodiment, the difference between the output voltages of the two topologies (single-phase three-level topology and center-tapped full-wave rectifier topology) can be changed by varying the input voltage to output DC voltages of different levels.

[0036] Exemplarily, the second winding of the coupling transformer is connected to three or more second AC-DC converters of three or more topological structures. In this case, the multi-port interconnection module can output three or more DC voltages of different levels.

[0037] In one embodiment, the first DC-AC converter adopts a single-phase three-level topology. In this embodiment, the single-phase three-level topology used as the first DC-AC converter has a higher output voltage than that of an H-bridge module. When the same level of DC input is used, a higher level of AC output can be achieved without cascading multiple H-bridge modules, thereby reducing the number of modules and the size.

[0038] Exemplarily, the single-phase three-level topology may be an I-type three-level topology, a T-type three-level topology, and an active neutral point clamped (ANPC) three-level topology.

[0039] In one embodiment, the multi-port interconnection module further includes: a first capacitor, a first inductor, a second capacitor, and a second inductor; the first DC-AC converter is connected to the first winding via the first capacitor and the first inductor; and the second AC-DC converter is connected to the second winding via the second capacitor and the second inductor.

[0040] As shown in FIG4 , a multi-port interconnection module including three first windings and two second windings is taken as an example for description.

[0041] Since the voltage waveform output by the three-level topology and the center-tapped full-wave rectifier topology is a square wave, which has a large loss when converted between transformers, the multi-port interconnection module can convert the waveform of the input coupling transformer from a square wave to a sine wave by connecting capacitors and inductors, thereby reducing the loss of voltage conversion between coupling transformers.

[0042] Taking the first DC-AC converter of the multi-port interconnection module in Figure 4 as an I-type three-level topology structure, and the second AC-DC converter including an I-type three-level topology structure and a center-tapped full-wave rectifier topology structure as an example, its connection structure schematic diagram is shown in Figure 5, wherein the first inductor L1 is connected to the midpoint position of the four switching tubes in the I-type three-level topology structure of the first DC-AC converter and the first winding, and the first capacitor C1 is connected to the first winding and the midpoint position of the clamping diode in the I-type three-level topology structure and the first winding.

[0043] When the second AC-DC converter topology is an I-type three-level topology, the second inductor L2 is connected to the midpoint of the four switching tubes in the I-type three-level topology of the second AC-DC converter and the second winding, and the second capacitor C2 is connected to the midpoint of the clamping diode in the I-type three-level topology of the second AC-DC converter and the second winding.

[0044] When the second AC-DC converter topology is a center-tapped full-wave rectifier topology, the second inductor L2 and the second capacitor C2 are connected in series, one end of which is connected to the center tap of the second winding, and the other end is connected to the two output terminals.

[0045] In one embodiment, the two different topologies in the multi-port interconnect module include a single-phase three-level topology and a center-tapped full-wave rectifier topology, and the first DC-AC converter utilizes a single-phase three-level topology. In this case, the single-phase three-level topology and the center-tapped full-wave rectifier topology in the multi-port interconnect module are controlled using synchronized 50% duty cycle pulses.

[0046] In this embodiment, the second AC-DC converter in the multi-port interconnect module includes at least two different topologies: a single-phase three-level topology and a center-tapped full-wave rectifier topology. Furthermore, when the first DC-AC converter adopts a single-phase three-level topology, each converter can be controlled using synchronized 50% duty cycle pulses to achieve soft switching, resulting in a simple control method.

[0047] For example, the pulses of the switches that are symmetrical relative to the midpoint of the four switches in the single-phase three-level topology are complementary. As shown in FIG5 , the first DC-AC converters are all I-type three-level topologies, and the control methods used are the same. The drive wave generation methods of the three first DC-AC converters in the figure are exactly the same. Taking the first first DC-AC converter as an example, the four switches are named S1, S2, S3, and S4 from top to bottom. The pulses of the four switches in the first first DC-AC converter are shown in FIG6 . The control pulses of S1 and S2 are the same, the control pulses of S3 and S4 are the same, and the control pulses of S1 and S4 are complementary.

[0048] As an example, the pulses of two switching transistors in a center-tapped full-wave rectifier topology are complementary. As shown in Figure 5 , the second AC-DC converter uses a center-tapped full-wave rectifier topology, with the switches designated S9 and S10 from top to bottom. The pulses of the switching transistors in the second AC-DC converter are shown in Figure 6 . The control pulses of S9 and S10 complement each other.

[0049] For example, the pulses of the switches connected to the same terminals of the coupling transformer in the single-phase three-level topology and the center-tapped full-wave rectifier topology are identical. Referring to FIG5 , the first DC-AC converters are all I-type three-level topologies and employ the same control method. The three first DC-AC converters in the figure have identical drive and wave generation methods. Taking the first DC-AC converter as an example, the four switches are named S1, S2, S3, and S4 from top to bottom. Similarly, the switches of the first second AC-DC converter are named S5, S6, S7, and S8 from top to bottom, and the switches of the second second AC-DC converter are named S9 and S10 from top to bottom.

[0050] Since S1 and S2, S5 and S6, and S9 are connected to one like-named terminal of the coupling transformer, and S3 and S4, S7 and S8, and S10 are connected to the other like-named terminal of the coupling transformer, as shown in Figure 6, the pulses of S1 and S2, S5 and S6, and S9 are identical, turning on or off simultaneously; while the pulses of S3 and S4, S7 and S8, and S10 are identical, turning on or off simultaneously. In Figure 6, there is a certain dead time between S9 and S10, and the duty cycles are misaligned because of the set dead time. In reality, the duty cycle of each switch is close to 50%. The dead time is exaggerated in Figure 6 to clarify the corresponding relationship.

[0051] Since the Insulated-Gate Bipolar Transistor (IGBT) is not an ideal switching device, its turn-on time and turn-off time are not strictly consistent. If there is voltage at both ends, it will cause the DC power supply to short-circuit and damage the bridge arm power device, which is called "bridge arm shoot-through". This situation will cause unnecessary additional losses in the device during the conduction process and even cause thermal runaway, which may result in damage to the device. Therefore, in order to ensure the reliable operation of the device, bridge arm shoot-through should be avoided, and "dead time" is generated. This means that one of the IGBTs must be turned off first, and then the other IGBT must be turned on at the end of the dead time. In this way, the shoot-through phenomenon caused by the asymmetry of the turn-on time and turn-off time can be avoided.

[0052] Before the switch tube in the multi-port interconnect module is turned on, the parasitic capacitance of the switch tube is precharged. During the turn-on process, the voltage in the circuit drops to zero, and the current then slowly rises to the on-state value. Therefore, the turn-on loss is approximately zero, and the voltage of the device junction capacitance is also zero, solving the capacitive turn-on problem. At the same time, the diode reverse recovery process has ended at the time of turn-on, so the diode reverse recovery problem does not exist. During the turn-off process of the switch tube, the current in the circuit first drops to zero, and the voltage then slowly rises to the off-state value. Therefore, the turn-off loss is approximately zero. Since the current of the switch tube device has dropped to zero before it is turned off, the inductive turn-off problem is solved, thus achieving soft switching.

[0053] Soft switching is the opposite of hard switching. By introducing resonance before and after the switching process, the voltage drops to zero before the switch turns on and the current drops to zero before the switch turns off. This eliminates the overlap of voltage and current during the switching process, reducing their rate of change, thereby significantly reducing or even eliminating switching losses. Simultaneously, the resonance process limits the rate of change of voltage and current during the switching process, significantly reducing switching noise.

[0054] It is worth noting that in the accompanying drawings, the switching tube of the first DC-AC converter is represented by an IGBT, and the switching tube of the second AC-DC converter is represented by a MOS tube. However, it can be understood that the switching tube can be a triode, a back cathode field effect transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET) and a bipolar junction transistor (BJT), etc. The switching tube of the first DC-AC converter and the switching tube of the second AC-DC converter can be selected according to actual needs.

[0055] In one embodiment, the multi-port interconnection module further includes: a plurality of first AC-DC converters, wherein the plurality of first AC-DC converters are correspondingly connected to the plurality of first DC-AC converters.

[0056] As shown in FIG7 , the first winding side of the coupling transformer in the multi-port interconnection module in this embodiment is further connected to a plurality of first AC-DC converters. The plurality of first AC-DC converters are correspondingly connected to the plurality of first DC-AC converters. The DC sides of the first AC-DC converters are connected to the DC sides of the first DC-AC converters, thereby enabling interconnection of multiple ACs and different levels of DC.

[0057] In one embodiment, the number of first AC-DC converters may be less than the number of first DC-AC converters, that is, the first winding side of the multi-port interconnection module can realize both AC input and DC input.

[0058] In one embodiment, the first AC-DC converter is a single-phase three-level full-bridge rectifier, and the input end of the single-phase three-level full-bridge rectifier includes a neutral terminal and a live terminal; the neutral terminals of at least three first AC-DC converters among the multiple first AC-DC converters are connected in parallel, and the multiple first AC-DC converters are used to access three-phase alternating current.

[0059] In another embodiment, the first AC-DC converter is a single-phase three-level full-bridge rectifier, and the input end of the single-phase three-level full-bridge rectifier includes a neutral terminal and a live terminal; at least two of the multiple first AC-DC converters are connected in series, and the multiple first AC-DC converters are used to access single-phase high-voltage alternating current.

[0060] The multi-port interconnection module provided in this embodiment can be slightly modified to form different circuit structures to meet different working requirements according to different application scenarios. As shown in Figure 9, three first AC-DC converters among the multiple first AC-DC converters can be connected in series to achieve the interconnection of a single-phase high-voltage AC with multiple DCs. As shown in Figure 11, the neutral terminals N of three first AC-DC converters among the multiple first AC-DC converters can be connected in parallel to achieve the interconnection of a three-phase AC with multiple DCs.

[0061] The following describes in detail the circuit structure of the multi-port interconnection module in different scenarios in the embodiments of the present application, taking a multi-port interconnection module including three first AC-DC converters and two second AC-DC converters as an example. The second AC-DC converter in the multi-port interconnection module includes at least two AC-DC converters with different topologies: a single-phase three-level topology and a center-tapped full-wave rectifier topology; the first DC-AC converter adopts a single-phase three-level topology, and the second AC-DC converter adopts a single-phase three-level full-bridge rectifier.

[0062] Illustratively, the multi-port interconnection module provided in this embodiment can realize the interconnection of three ACs and at least two DCs.

[0063] As shown in FIG8 , three single-phase alternating currents can be input to the first winding side of the coupling transformer through the first DC-AC converter and the first AC-DC converter connected in series, and two different levels of direct current can be output to the second winding side of the coupling transformer through the second AC-DC converter. The multi-port interconnection module provided in this embodiment realizes the interconnection of three single-phase alternating currents and at least two different levels of direct current.

[0064] Illustratively, the multi-port interconnection module provided in this embodiment can also realize the interconnection between a high-voltage single-phase alternating current and at least two direct currents.

[0065] As shown in FIG10 , by connecting three first AC-DC converters in series, that is, connecting the neutral terminal N of the first first AC-DC converter to the live terminal L of the second first AC-DC converter, and connecting the neutral terminal N of the second first AC-DC converter to the live terminal L of the third first AC-DC converter, the input terminals on the first winding side of the coupling transformer only include the live terminal L of the first first AC-DC converter and the neutral terminal N of the third first AC-DC converter. This allows a high-voltage single-phase AC input to be input to the second winding side of the coupling transformer; and two DC currents can be output on the second winding side of the coupling transformer via the second AC-DC converter. Therefore, by connecting the three first AC-DC converters in series in the multi-port interconnection module provided in this embodiment, interconnection between a high-voltage single-phase AC current and at least two DC currents of different levels can be achieved.

[0066] Illustratively, the multi-port interconnection module provided in this embodiment can also realize the interconnection between a three-phase alternating current and at least two direct currents.

[0067] As shown in FIG12 , by connecting the neutral terminals N of the three first AC-DC converters in parallel, for example, the input terminals on the first winding side of the coupling transformer include only the live terminals L of the three first AC-DC converters and the neutral terminal N of the third first AC-DC converter. This allows three-phase AC to be input to the first winding side of the coupling transformer, and two DCs to be output on the second winding side of the coupling transformer via the second AC-DC converter. Therefore, by connecting the neutral terminals N of the three first AC-DC converters in parallel in the multi-port interconnection module provided in this embodiment, interconnection between one three-phase AC and at least two DCs can be achieved.

[0068] In the embodiment of the present application, at least five modules are coupled together by a co-coupled transformer, wherein the three modules on the left side adopt a three-level architecture, which can reduce the number of modules when cascading, or connect an inverter to build a single-phase or three-phase topology; one of the low-voltage side modules on the right side adopts a three-level half-bridge to output a higher voltage level DC, and the other module adopts a full-wave bidirectional rectifier to output a lower level DC, which can reduce the loss at low voltage output. This topological isolation adopts a high-frequency isolation form and uses a simple control mode to achieve soft switching, which has the advantage of high efficiency. The energy flow of the multi-port power module needs to be controlled, and AC / DC voltage decoupling and energy control are achieved through different mode controls.

[0069] In one embodiment, the first DC-AC converter is a bidirectional inverter, and the second AC-DC converter is a bidirectional rectifier. Thus, in the multi-port interconnect module of this embodiment, energy on the first winding side of the coupling transformer can be transferred to the second winding side of the coupling transformer, and energy on the second winding side of the coupling transformer can be transferred to the first winding side of the coupling transformer, thereby enabling bidirectional energy flow.

[0070] Exemplarily, when the multi-port interconnection module further includes a plurality of first AC-DC converters, in order to achieve bidirectional flow of energy, the first AC-DC converters are also bidirectional rectifiers.

[0071] In one embodiment, each winding of the coupling transformer has the same number of turns. Assuming that the coupling transformer has three first windings and two second windings, the turns ratio of the first winding to the second winding is 1:1:1:1:1.

[0072] In other examples, the multiple first windings have the same number of turns, while the multiple second windings have different numbers of turns, and the number of turns of the first windings differs from the number of turns of the second windings. Assuming the coupling transformer has three first windings and two second windings, the turns ratio of the first and second windings can be N:N:N:X:Y. In this case, the first DC-AC converter connected to the first winding transmits pulses with the same duty cycle, i.e., a 50% duty cycle. However, the control pulses of the multiple second AC-DC converters connected to the second windings differ, requiring the corresponding modulation wave generation algorithm to calculate the duty cycle of the control pulses.

[0073] Exemplarily, each of the second AC-DC converters of the multi-port interconnection module can be directly connected to a load or a DC power source.

[0074] Exemplarily, the second AC-DC converters of the multi-port interconnection module may be connected in series and then connected to a load or a DC power source to increase the output DC voltage or the input DC voltage.

[0075] An embodiment of the present application also provides a multi-port interconnection system, comprising: at least two multi-port interconnection modules as described in the above embodiment; the multi-port interconnection module includes multiple first AC-DC converters, and the multiple first AC-DC converters are correspondingly connected to the multiple first DC-AC converters; the AC sides of at least two first AC-DC converters in the multi-port interconnection module are connected in series; the AC sides of at least two multi-port interconnection modules are connected in series, and the AC sides of at least two multi-port interconnection modules are used to access single-phase high-voltage AC.

[0076] In this embodiment, a multi-port interconnection module including three first AC-DC converters, three first DC-AC converters, and two second AC-DC converters is used as an example for description:

[0077] The coupling transformer of the multi-port interconnect module includes three first windings and two second windings. The three first windings are connected to the three first DC-AC converters, and the first windings are connected to the AC side of the first DC-AC converters, and the DC side of the first DC-AC converters is connected to the DC side of the first AC-DC converter. The two second windings are connected to the two second AC-DC converters, and the second windings are connected to the AC side of the second AC-DC converters.

[0078] The three first AC-DC converters in the multi-port interconnection module are connected in series. That is, the neutral terminal of the first first AC-DC converter is connected to the live terminal of the second first AC-DC converter, and the neutral terminal of the second first AC-DC converter is connected to the live terminal of the third first AC-DC converter. In this way, the input terminals on the first winding side of the coupling transformer only include the live terminal of the first first AC-DC converter and the neutral terminal of the third first AC-DC converter.

[0079] Referring to Figure 13, the first winding sides of the three multi-port interconnected modules in the multi-port interconnected system are also connected in series, that is, the neutral terminal of the first multi-port interconnected module is connected to the live terminal of the second multi-port interconnected module, and the neutral terminal of the second multi-port interconnected module is connected to the live terminal of the third multi-port interconnected module. In this way, the input terminal of the first winding side of the multi-port interconnected system in the embodiment of the present application only includes the live terminal of the first multi-port interconnected module and the neutral terminal of the third multi-port interconnected module. The AC sides of these three multi-port interconnected modules are used to connect to single-phase high-voltage AC. The multi-port interconnected system can realize the interconnection of a single-phase high-voltage AC and multiple DCs.

[0080] Exemplarily, the second AC-DC converter of the multi-port interconnection module in the multi-port interconnection system can be directly connected to the load or the DC input, or the second AC-DC converters can be connected in series and then connected to the load or the DC input.

[0081] Exemplarily, the second AC-DC converter of the multi-port interconnected modules in the multi-port interconnected system includes at least a single-phase three-level topology and a center-tapped full-wave rectifier topology. Multiple modules in the multi-port interconnected system with single-phase three-level topologies can be connected in parallel and then connected to a load or a DC input. Multiple modules in the multi-port interconnected system with center-tapped full-wave rectifier topologies can be connected in parallel and then connected to a load or a DC input.

[0082] An embodiment of the present application also provides a multi-port interconnection system, comprising: at least three multi-port interconnection modules as described in the above embodiment; the multi-port interconnection module includes multiple first AC-DC converters, and the multiple first AC-DC converters are correspondingly connected to the multiple first DC-AC converters; the AC sides of at least two first AC-DC converters in the multi-port interconnection module are connected in series; the neutral terminals of the AC sides of at least three multi-port interconnection modules are connected in parallel, and the AC sides of at least three multi-port interconnection modules are used to access three-phase AC.

[0083] In this embodiment, a multi-port interconnection module including three first AC-DC converters, three first DC-AC converters, and two second AC-DC converters is used as an example for description:

[0084] The coupling transformer of the multi-port interconnect module includes three first windings and two second windings. The three first windings are connected to the three first DC-AC converters, and the first windings are connected to the AC side of the first DC-AC converters, and the DC side of the first DC-AC converters is connected to the DC side of the first AC-DC converter. The two second windings are connected to the two second AC-DC converters, and the second windings are connected to the AC side of the second AC-DC converters.

[0085] The three first AC-DC converters in the multi-port interconnection module are connected in series. That is, the neutral terminal of the first first AC-DC converter is connected to the live terminal of the second first AC-DC converter, and the neutral terminal of the second first AC-DC converter is connected to the live terminal of the third first AC-DC converter. In this way, the input terminals on the first winding side of the coupling transformer only include the live terminal of the first first AC-DC converter and the neutral terminal of the third first AC-DC converter.

[0086] As shown in Figure 14, the neutral terminals on the first winding side of three multi-port interconnected modules in a multi-port interconnected system are connected in parallel. Thus, in this embodiment of the present application, the input terminals on the first winding side of the multi-port interconnected system only include the live terminal of the first multi-port interconnected module, the live terminal of the second multi-port interconnected module, the live terminal of the third multi-port interconnected module, and the parallel-connected neutral terminal. The three live terminals and the parallel-connected neutral terminal on the first winding side of the multi-port interconnected system can be used to connect to a three-phase AC. This multi-port interconnected system can interconnect a three-phase AC with multiple DCs.

[0087] Exemplarily, the second AC-DC converter of the multi-port interconnection module in the multi-port interconnection system can be directly connected to the load or the DC input, or the second AC-DC converters can be connected in series and then connected to the load or the DC input.

[0088] Exemplarily, the second AC-DC converter of the multi-port interconnected modules in the multi-port interconnected system includes at least a single-phase three-level topology and a center-tapped full-wave rectifier topology. Multiple modules in the multi-port interconnected system with single-phase three-level topologies can be connected in parallel and then connected to a load or a DC input. Multiple modules in the multi-port interconnected system with center-tapped full-wave rectifier topologies can be connected in parallel and then connected to a load or a DC input.

[0089] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or system comprising the element.

[0090] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a number of instructions for enabling a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0091] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A multi-port interconnection module, the multi-port interconnection module comprising: A coupling transformer, the coupling transformer comprising a plurality of first windings and a plurality of second windings, wherein the first windings and the second windings are distributed on different sides of the coupling transformer; A plurality of first DC-AC converters, wherein the AC sides of the plurality of first DC-AC converters are connected correspondingly to the plurality of first windings; A plurality of second AC-DC converters, wherein the AC sides of the plurality of second AC-DC converters are correspondingly connected to the plurality of second windings, and the plurality of second AC-DC converters include at least two different topological structures.

2. The multi-port interconnect module according to claim 1, wherein: The two different topological structures include: a single-phase three-level topological structure and a center-tapped full-wave rectification topological structure.

3. The multi-port interconnect module according to claim 1 or 2, wherein: The first DC-AC converter adopts a single-phase three-level topology structure.

4. The multi-port interconnect module according to claim 2, wherein: The first DC-AC converter adopts a single-phase three-level topology; The single-phase three-level topology structure and the center-tapped full-wave rectification topology structure in the multi-port interconnection module are controlled by synchronous pulses with a duty cycle of 50%.

5. The multi-port interconnect module according to claim 4, wherein: The pulses of the switch tubes that are symmetrical relative to the midpoints of the four switch tubes in the single-phase three-level topology are complementary.

6. The multi-port interconnect module according to claim 4, wherein: The pulses of the two switching tubes in the center-tapped full-wave rectifier topology are complementary.

7. The multi-port interconnection module according to any one of claims 4 to 6, wherein: The pulses of the switch tubes connected to the same-named ends of the coupling transformer in the single-phase three-level topology structure and the center-tapped full-wave rectification topology structure are the same.

8. The multi-port interconnect module according to claim 1, wherein: The multi-port interconnection module also includes: a plurality of first AC-DC converters, and the plurality of first AC-DC converters are correspondingly connected to the plurality of first DC-AC converters.

9. The multi-port interconnect module according to claim 8, wherein: The first AC-DC converter is a single-phase three-level full-bridge rectifier, and the input end of the single-phase three-level full-bridge rectifier includes a neutral terminal and a live terminal; Neutral terminals of at least three of the plurality of first AC-DC converters are connected in parallel, and the plurality of first AC-DC converters are used to access three-phase alternating current.

10. The multi-port interconnect module according to claim 8, wherein: The first AC-DC converter is a single-phase three-level full-bridge rectifier, and the input end of the single-phase three-level full-bridge rectifier includes a neutral terminal and a live terminal; At least two of the plurality of first AC-DC converters are connected in series, and the plurality of first AC-DC converters are used to access single-phase high-voltage alternating current.

11. The multi-port interconnection module according to any one of claims 1 to 10, wherein: The number of turns of each winding of the coupling transformer is the same.

12. The multi-port interconnection module according to any one of claims 1 to 10, wherein: The plurality of first windings have the same number of turns, the plurality of second windings have different numbers of turns, and the number of turns of the first winding is different from the number of turns of the second winding.

13. A multi-port interconnection system, comprising: At least two multi-port interconnect modules according to any one of claims 1 to 12; The multi-port interconnection module includes a plurality of first AC-DC converters, and the plurality of first AC-DC converters are correspondingly connected to the plurality of first DC-AC converters; The AC sides of at least two of the first AC-DC converters in the multi-port interconnect module are connected in series; The AC sides of at least two of the multi-port interconnect modules are connected in series, and the AC sides of at least two of the multi-port interconnect modules are used to access single-phase high-voltage AC.

14. A multi-port interconnection system, comprising: At least three multi-port interconnect modules according to any one of claims 1 to 12; The multi-port interconnection module includes a plurality of first AC-DC converters, and the plurality of first AC-DC converters are correspondingly connected to the plurality of first DC-AC converters; The AC sides of at least two of the first AC-DC converters in the multi-port interconnect module are connected in series; The neutral terminals of the AC sides of at least three of the multi-port interconnect modules are connected in parallel, and the AC sides of at least three of the multi-port interconnect modules are used to access three-phase AC.

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