Multi-port interconnection module and system

Abstract

The invention discloses a multi-port interconnection module and system, and belongs to the technical field of power electronics, the multi-port interconnection module comprises a coupling transformer, the coupling transformer comprises a plurality of first windings and a plurality of second windings, and 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 correspondingly connected with the plurality of first windings; and a plurality of second AC-DC converters, the AC sides of the plurality of second AC-DC converters are correspondingly connected with the plurality of second windings, and the plurality of second AC-DC converters at least comprise two different topological structures. The multi-port interconnection module and system provided by the embodiment of the invention can solve the problems that the number of modules is large and the cost is high when different levels of direct current are realized in the prior art.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and particularly to a multi-port interconnection module and system. Background Art

[0002] With the development of power systems, AC-DC hybrid power supply technology is considered to be the development direction. The traditional AC-DC hybrid technology uses a multi-port transformer to connect multiple H-bridge modules to construct an AC-DC hybrid module. However, this solution requires a large number of modules and high costs when implementing different levels of DC. Summary of the Invention

[0003] The main purpose of this application is to provide a multi-port interconnection module and system, aiming to solve the problems of a large number of modules and high costs in the related technology when implementing different levels of DC.

[0004] To achieve the above object, an embodiment of this application provides a multi-port interconnection module, which includes:

[0005] A coupling transformer, which includes a plurality of first windings and a plurality of second windings, and the first windings and the second windings are distributed on different sides of the coupling transformer;

[0006] A plurality of first DC-AC converters, and the AC sides of the plurality of first DC-AC converters are correspondingly connected to the plurality of first windings;

[0007] A plurality of second AC-DC converters, and 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.

[0008] An embodiment of this application also provides a multi-port interconnection system, which includes at least three multi-port interconnection modules as described in the above embodiment;

[0009] 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;

[0010] The AC sides of at least two of the first AC-DC converters in the multi-port interconnection module are connected in series,

[0011] The neutral terminals of the AC sides of at least three multi-port interconnection modules are connected in parallel for accessing three-phase AC.

[0012] An embodiment of this application also provides a multi-port interconnection system, which includes at least two multi-port interconnection modules as described in the above embodiment;

[0013] 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;

[0014] In the multi-port interconnection module, the AC sides of at least two of the first AC-DC converters are connected in series;

[0015] The AC sides of at least two of the multi-port interconnection modules are connected in series for accessing single-phase high-voltage AC.

[0016] The embodiment of the present application discloses a multi-port interconnection module. A plurality of first DC-AC converters and a plurality of second AC-DC converters are coupled and connected through a coupling transformer to form a multi-port DC-DC interconnection module. Moreover, the second AC-DC converter includes two different topological structures. Therefore, the multi-port interconnection module in the embodiment of the present application can realize direct currents of different levels. Compared with a multi-port transformer connecting multiple H-bridge modules and connecting multiple H-bridge modules in series to realize direct currents of different levels, the number of modules required in the embodiment of the present application for realizing different levels of direct current is less, the structure is simple, and the cost is low. And in the embodiment of the present application, a coupling transformer is used to connect a plurality of first DC-AC converters and a plurality of second AC-DC converters, realizing electrical isolation of each converter. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of an embodiment of the AC-DC interconnection module related to the solution of the embodiment of the present application;

[0018] Figure 2 is a topological structure of the second AC-DC converter in the AC-DC interconnection module related to the solution of the embodiment of the present application;

[0019] Figure 3 is another topological structure of the second AC-DC converter in the AC-DC interconnection module related to the solution of the embodiment of the present application;

[0020] Figure 4 is a schematic structural diagram of an embodiment of the AC-DC interconnection module related to the solution of the embodiment of the present application;

[0021] Figure 5 is Figure 4 a schematic circuit structure diagram of an embodiment of the shown AC-DC interconnection module;

[0022] Figure 6 is Figure 5 a waveform diagram of the switching tube in the shown AC-DC interconnection module;

[0023] Figure 7 is a schematic structural diagram of an embodiment of the AC-DC interconnection module related to the solution of the embodiment of the present application;

[0024] Figure 8 is Figure 7 A schematic circuit diagram of an embodiment of the AC-DC interconnected module shown;

[0025] Figure 9 A schematic structural diagram of an embodiment of the AC-DC interconnected module involved in the embodiment solution of the present application;

[0026] Figure 10 is Figure 9 A schematic circuit diagram of an embodiment of the AC-DC interconnected module shown;

[0027] Figure 11 A schematic structural diagram of an embodiment of the AC-DC interconnected module involved in the embodiment solution of the present application;

[0028] Figure 12 is Figure 11 A schematic circuit diagram of an embodiment of the AC-DC interconnected module shown;

[0029] Figure 13 A schematic structural diagram of an embodiment of the AC-DC interconnected system involved in the embodiment solution of the present application;

[0030] Figure 14 A schematic structural diagram of another embodiment of the AC-DC interconnected system involved in the embodiment solution of the present application.

[0031] The realization of the purpose of the present application, functional features and advantages will be further described with reference to the embodiments and the accompanying drawings. Specific Embodiments

[0032] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] With the development of the energy Internet, the integration and interconnection of AC and DC have become a very crucial issue, and it is necessary to connect electric energies of different voltage levels and forms, and different ports need to adopt isolation or non-isolation structures according to the situation. For example, in household or industrial scenarios, both alternating current (such as motors, household appliances, etc.) and direct current (such as electric vehicles, etc.) are used. Therefore, it is necessary to design a circuit structure that can integrate AC and DC, so that inputting an alternating current or a direct current into this circuit structure can output direct currents and alternating currents of different voltage levels.

[0034] Currently, the related technologies generally adopt the common bus method to implement the above circuit structure, that is, an AC bus or a DC bus is constructed, and each port is connected by different topologies. For example: in a circuit structure, an AC bus is used to provide alternating current, and multiple transformers are connected in parallel on the AC bus. Rectifiers (such as H-bridge rectifiers) are connected to some of the transformers to convert the alternating current into direct current for output. Different levels of direct current can also be output by connecting multiple rectifiers in series or in parallel; rectifiers and inverters are connected in series to some of the transformers to output alternating current, and different levels of alternating current input can also be supported by connecting multiple inverters (such as H-bridge inverters) in series or in parallel. In this way, only one kind of alternating current needs to be input in the whole circuit structure, and different levels of alternating current and direct current can be output, realizing the integration of AC and DC.

[0035] However, in the above circuit structure, the bus and multiple transformers are used for connection, which has the problems of large volume, high cost, many conversion links, and low conversion efficiency. Therefore, a circuit structure that can be compatible with alternating current and direct current of multiple voltage levels is needed to achieve the purpose of reducing volume, lowering cost, reducing conversion links, and improving conversion efficiency.

[0036] In the related technologies, 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 bus and multiple transformers, it can reduce the volume and the number of conversion links. However, when realizing different levels of DC output, it is necessary to connect the H-bridge modules in series or connect different levels of DC modules to output different levels of DC voltage, which requires a large number of modules and high costs.

[0037] In view of this, in the embodiments of the present application, a multi-port interconnection module is provided, including: a coupling transformer, the coupling transformer includes multiple first windings and multiple second windings, and 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 at least include two different topologies.

[0038] The coupling transformer is a multi-port transformer, and both the primary winding and the secondary winding are multiple. 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. Refer to Figure 1 As shown, the windings on the left side of the coupling transformer are the first windings, and the windings on the right side of the coupling transformer are the second windings.

[0039] Exemplarily, the coupling transformer is a high-frequency transformer, which is a power transformer with a working frequency exceeding the intermediate frequency (10 kHz). According to the working frequency, it can be divided into several grades: 10 kHz - 50 kHz, 50 kHz - 100 kHz, 100 kHz to 500 kHz, 500 kHz to 1 MHz, above 10 MHz.

[0040] Exemplarily, at least two different topological structures, such as: three-level topological structure, full-wave rectifier topological structure, half-bridge rectifier topological structure, full-bridge rectifier topological structure, voltage multiplier rectifier topological structure. In this embodiment, the second winding of the coupling transformer is connected to at least two different topological structures 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 topological structures.

[0041] 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. And 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 direct current. 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, has a simple structure and a lower cost when realizing different levels of DC output. And in the embodiment of the present application, a coupling transformer is used to connect multiple first DC-AC converters and multiple second AC-DC converters, realizing electrical isolation of multiple conversion modules.

[0042] In one embodiment, the two different topological structures include: single-phase three-level topological structure and center-tapped full-wave rectifier topological structure.

[0043] The single-phase three-level topological structure can be Figure 2 the I-type three-level topological structure shown, or the T-type three-level topological structure or the active neutral point clamped (ANPC) three-level topological structure; the center-tapped full-wave rectifier topological structure is as Figure 3 shown.

[0044] 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 voltages are different, the multiple difference between the voltages output by the single-phase three-level topology and the center-tapped full-wave rectifier topology changes. In this embodiment, the multiple difference between the voltages output by the two topologies can be changed by changing the voltages of the two input topologies (the single-phase three-level topology and the center-tapped full-wave rectifier topology) to output DC voltages of different levels.

[0045] Exemplarily, the second winding of the coupling transformer is connected to the second AC-DC converters of three or more topologies. At this time, the multi-port interconnection module can output DC voltages of three or more different levels.

[0046] In one embodiment, the first DC-AC converter adopts a single-phase three-level topology. In this embodiment, the single-phase three-level topology is adopted as the first DC-AC converter. Compared with using an H-bridge module, the single-phase three-level topology outputs a higher voltage. When inputting DC of the same level, a higher-level AC can be output without cascading multiple H-bridge modules, which can reduce the number of modules and the volume.

[0047] Exemplarily, the single-phase three-level topology can be an I-type three-level topology, a T-type three-level topology, and an active neutral point clamped (ANPC) three-level topology.

[0048] 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 through the first capacitor and the first inductor; the second AC-DC converter is connected to the second winding through the second capacitor and the second inductor.

[0049] As Figure 4 shown, taking the multi-port interconnection module including three first windings and two second windings as an example for illustration.

[0050] Since the voltage waveforms output by the three-level topology and the center-tapped full-wave rectifier topology are square waves, and the square wave waveforms have large losses when transformed between transformers, therefore, in the multi-port interconnection module, by connecting capacitors and inductors, the waveform input to the coupling transformer can be converted from a square wave to a sine wave, thereby reducing the losses of voltage transformation between the coupling transformers.

[0051] Taking Figure 4The first DC-AC converter of the multi-port interconnection module is of the I-type three-level topology. Taking the second AC-DC converter including the I-type three-level topology and the center-tapped full-wave rectifier topology as an example, the schematic diagram of its connection structure is as Figure 5 shown. Among them, the first inductor L1 is connected to the midpoint of the four switching tubes in the I-type three-level topology of the first DC-AC converter and the first winding, and the first capacitor C1 is connected to the midpoint of the clamping diodes in the I-type three-level topology and the first winding and the first winding.

[0052] In the case where the topology of the second AC-DC converter is the 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 diodes in the I-type three-level topology of the second AC-DC converter and the second winding.

[0053] In the case where the topology of the second AC-DC converter is the center-tapped full-wave rectifier topology, the second inductor L2 and the second capacitor C2 are connected in series, one end is connected to the center tap of the second winding, and the other end is connected to the two output terminals.

[0054] In one embodiment, the two different topologies in the multi-port interconnection module include: the single-phase three-level topology and the center-tapped full-wave rectifier topology, and the first DC-AC converter adopts the single-phase three-level topology. At this time, the single-phase three-level topology and the center-tapped full-wave rectifier topology in the multi-port interconnection module are controlled by synchronous pulses with a 50% duty cycle.

[0055] In this embodiment, it is given that the second AC-DC converter in the multi-port interconnection module includes at least two different topologies: the single-phase three-level topology and the center-tapped full-wave rectifier topology, and when the first DC-AC converter adopts the single-phase three-level topology, each converter can be controlled by synchronous pulses with a 50% duty cycle to achieve soft switching, and the control method is simple.

[0056] Exemplarily, the pulses of the switching tubes symmetric with respect to the midpoint of the four switching tubes in the single-phase three-level topology are complementary. As Figure 5 shown, all the first DC-AC converters are of the I-type three-level topology and adopt the same control method. The driving waveform 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 switching tubes are named S1, S2, S3, and S4 from top to bottom. The pulses of the four switching tubes in the first first DC-AC converter are shown in Figure 6, 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.

[0057] Exemplarily, the pulses of two switching tubes in a center-tapped full-wave rectifier topology are complementary. As Figure 5 shown, the second second AC-DC converter is a center-tapped full-wave rectifier topology, and its switching tubes are named S9 and S10 from top to bottom. For the pulses of the switching tubes in the second second AC-DC converter, refer to Figure 6 , the control pulses of S9 and S10 are complementary.

[0058] Exemplarily, the pulses of the switching tubes connecting the same-named terminals of the coupling transformer in a single-phase three-level topology and a center-tapped full-wave rectifier topology are the same. Refer to Figure 5 , the first DC-AC converters are all type-I three-level topologies and adopt the same control method. The driving waveform 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 4 switching tubes are named S1, S2, S3, and S4 from top to bottom. Similarly, the switching tubes of the first second AC-DC converter are named S5, S6, S7, and S8 from top to bottom, and the switching tubes of the second second AC-DC converter are named S9 and S10 from top to bottom.

[0059] Since S1 and S2, S5 and S6, and S9 are connected to one of the same-named terminals of the coupling transformer, and S3 and S4, S7 and S8, and S10 are connected to the other same-named terminal of the coupling transformer. Refer to Figure 6 , the pulses of S1 and S2, S5 and S6, and S9 are the same, either turned on simultaneously or turned off simultaneously; the pulses of S3 and S4, S7 and S8, and S10 are the same, either turned on simultaneously or turned off simultaneously. Figure 6 There is a certain dead time between S9 and S10 in , and the duty cycles are not aligned because a certain dead time is set. Actually, the duty cycles of each switching tube are all close to 50%, Figure 6 in , the dead time is amplified to make the corresponding relationship clearer.

[0060] Since the Insulated-Gate Bipolar Transistor (IGBT) is not an ideal switching device, its turn-on time and turn-off time are not strictly the same. If there is voltage across its two ends, it will cause a short circuit of the DC power supply and damage the power device of the bridge arm, which is called "bridge arm shoot-through". This situation will lead to unnecessary additional losses during the conduction process of the device, and even cause out-of-control heating, and the result may be that the device is damaged. Therefore, in order to ensure the reliable operation of the device, bridge arm shoot-through should be avoided, and the "dead time" is generated. This means that one IGBT has to be turned off first, and then the other IGBT is 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.

[0061] Before the switch tube in the above multi-port interconnection module is turned on, the parasitic capacitance of the switch tube is pre-charged. 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 problem of capacitive turn-on. At the same time, when it is turned on, the reverse recovery process of the diode has ended, so the problem of diode reverse recovery 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 turning off, the problem of inductive turn-off is solved, thus realizing soft switching.

[0062] Soft-Switching is relative to Hard-Switching. By introducing resonance before and after the switching process, the voltage can be reduced to zero before the switch is turned on, and the current can be reduced to zero before the switch is turned off, so that the overlap of voltage and current during the switching process can be eliminated, and their change rates can be reduced, thereby greatly reducing or even eliminating the switching loss. At the same time, the resonance process limits the change rates of voltage and current during the switching process, which significantly reduces the switching noise.

[0063] It should be noted that the switch tubes of the first DC-AC converter in the attached drawings are represented by IGBTs, and the switch tubes of the second AC-DC converter are represented by MOS tubes. However, it can be understood that the switch tubes can be triodes, insulated-gate bipolar transistors (IGBTs), metal-oxide-semiconductor field-effect transistors (MOSFETs), bipolar junction transistors (BJTs), etc., and the switch tubes of the first DC-AC converter and the second AC-DC converter can be selected according to actual needs.

[0064] In one embodiment, the multi-port interconnection module further 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.

[0065] Such asFigure 7 As shown in the figure, in this embodiment, a plurality of first AC-DC converters are further connected to the first winding side of the coupling transformer in the multi-port interconnection module. The plurality of first AC-DC converters are correspondingly connected to the plurality of first DC-AC converters. The DC side of the first AC-DC converter is connected to the DC side of the first DC-AC converter, enabling the interconnection of multiple ACs and different levels of DCs.

[0066] In one embodiment, the number of the first AC-DC converters can be less than the number of the first DC-AC converters. That is to say, on the first winding side of the multi-port interconnection module, AC input can be achieved, and DC input can also be achieved.

[0067] In one embodiment, the first AC-DC converter is a single-phase three-level full-bridge rectifier. The input end of the single-phase three-level full-bridge rectifier includes a neutral line terminal and a live line terminal; the neutral line 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.

[0068] In another embodiment, the first AC-DC converter is a single-phase three-level full-bridge rectifier. The input end of the single-phase three-level full-bridge rectifier includes a neutral line terminal and a live line 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.

[0069] The multi-port interconnection module provided in this embodiment can slightly modify the circuit structure of the multi-port interconnection module according to different application scenarios to form different circuit structures to meet different working requirements. As Figure 9 shown, three of the plurality of first AC-DC converters can be connected in series to achieve the interconnection of a single-phase high-voltage AC and multiple DCs. As Figure 11 shown, the neutral line terminals N of three of the plurality of first AC-DC converters can be connected in parallel to achieve the interconnection of a three-phase AC and multiple DCs.

[0070] Taking the multi-port interconnection module including three first AC-DC converters and two second AC-DC converters as an example, the circuit structures of the multi-port interconnection module in different scenarios in the embodiments of the present application will be described in detail. Among them, the second AC-DC converter in the multi-port interconnection module includes at least two AC-DC converters with different topological structures, namely, a single-phase three-level topological structure and a center-tapped full-wave rectification topological structure; the first DC-AC converter adopts a single-phase three-level topological structure, and the first AC-DC converter adopts a single-phase three-level full-bridge rectifier.

[0071] Exemplarily, the multi-port interconnection module provided in this embodiment can achieve the interconnection of three alternating currents and at least two direct currents.

[0072] As Figure 8 shown, three single-phase alternating currents can be input on 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 direct currents with different levels can be output on 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 direct currents with different levels.

[0073] Exemplarily, the multi-port interconnection module provided in this embodiment can also achieve the interconnection of one high-voltage single-phase alternating current and at least two direct currents.

[0074] As Figure 10 shown, by connecting three first AC-DC converters in series, that is, the neutral terminal N of the first first AC-DC converter is connected to the live terminal L of the second first AC-DC converter, and the neutral terminal N of the second first AC-DC converter is connected to the live terminal L 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 L of the first first AC-DC converter and the neutral terminal N of the third first AC-DC converter, and a high-voltage single-phase alternating current can be input on the second winding side of the coupling transformer; two direct currents can be output on the second winding side of the coupling transformer through the second AC-DC converter. Therefore, by connecting three first AC-DC converters in series in the multi-port interconnection module provided in this embodiment, the interconnection of one high-voltage single-phase alternating current and at least two direct currents with different levels can be achieved.

[0075] Exemplarily, the multi-port interconnection module provided in this embodiment can also achieve the interconnection of one three-phase alternating current and at least two direct currents.

[0076] As Figure 12 shown, by connecting the neutral terminals N of three first AC-DC converters in parallel, for example: the input terminals on the first winding side of the coupling transformer only include the live terminals L of the three first AC-DC converters and the neutral terminal N of the third first AC-DC converter, and a three-phase alternating current can be input on the first winding side of the coupling transformer; two direct currents can be output on the second winding side of the coupling transformer through the second AC-DC converter. Therefore, by connecting the neutral terminals N of three first AC-DC converters in parallel in the multi-port interconnection module provided in this embodiment, the interconnection of one three-phase alternating current and at least two direct currents can be achieved.

[0077] In the embodiments of the present application, at least five modules are coupled together through a common coupling transformer. Among them, the three modules on the left adopt a three-level architecture, which can reduce the number of modules during cascading or connect to an inverter to construct a single-phase or three-phase topology; one of the modules on the low-voltage side on the right adopts a three-level half-bridge to output a DC with a higher voltage level, and the other module adopts a full-wave bidirectional rectifier to output a DC with a lower level, which can reduce the loss during low-voltage output. The topology 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 the AC-DC voltage decoupling and energy control are achieved through different mode controls.

[0078] In one embodiment, the first DC-AC converter is a bidirectional inverter, and the second AC-DC converter is a bidirectional rectifier. Thus, the energy on the first winding side of the coupling transformer in the multi-port interconnection module in this embodiment can be transferred to the second winding side of the coupling transformer, and the energy on the second winding side of the coupling transformer can be transferred to the first winding side of the coupling transformer, and the multi-port interconnection module can achieve bidirectional energy flow.

[0079] Exemplarily, when the multi-port interconnection module further includes a plurality of first AC-DC converters, in order to achieve bidirectional energy flow, the first AC-DC converter is also a bidirectional rectifier.

[0080] In one embodiment, the number of turns of each winding of the coupling transformer is the same. Assuming that the first winding of the coupling transformer has three turns and the second winding has two turns, the turn ratio of the first winding to the second winding is 1:1:1:1:1.

[0081] In some other examples, the number of turns of the multiple first windings is the same, the number of turns of the multiple second windings is different, and the number of turns of the first winding is different from that of the second winding. Assuming that the first winding of the coupling transformer has three turns and the second winding has two turns, the turn ratio of the first winding to the second winding can be N:N:N:X:Y. At this time, the first DC-AC converter connected to the first winding sends pulses with the same duty cycle, that is, pulses with a duty cycle of 50%, but the control pulses of the multiple second AC-DC converters connected to the second winding are different, and the duty cycle of the control pulses needs to be calculated through the corresponding modulation wave algorithm.

[0082] Exemplarily, the second AC-DC converter of the multi-port interconnection module can be directly connected to a load or a DC power supply.

[0083] Exemplarily, the second AC-DC converters of the multi-port interconnection module can be connected in series and then connected to a load or a DC power supply to increase the output DC voltage or the input DC voltage.

[0084] The embodiment of the present application further provides a multi-port interconnection system, including: at least two multi-port interconnection modules as described in the above embodiment; 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 a plurality of first DC-AC converters; at least two first AC-DC converters in the multi-port interconnection module are connected in series on the AC side; 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.

[0085] In this embodiment, an example is given where the multi-port interconnection module includes three first AC-DC converters, three first DC-AC converters, and two second AC-DC converters:

[0086] The coupling transformer of the multi-port interconnection module includes three first windings and two second windings. The three first windings are correspondingly connected to the three first DC-AC converters, and the first winding is connected to the AC side of the first DC-AC converter. The DC side of the first DC-AC converter is connected to the DC side of the first AC-DC converter. The two second windings are correspondingly connected to the two second AC-DC converters, and the second winding is connected to the AC side of the second AC-DC converter.

[0087] The three first AC-DC converters in the multi-port interconnection module are connected in series. That is to say, 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.

[0088] See Figure 13 , the first winding sides of the three multi-port interconnection modules in the multi-port interconnection system are also connected in series. That is to say, the neutral terminal of the first multi-port interconnection module is connected to the live terminal of the second multi-port interconnection module, and the neutral terminal of the second multi-port interconnection module is connected to the live terminal of the third multi-port interconnection module. In this way, the input terminals on the first winding side of the multi-port interconnection system in the embodiment of the present application only include the live terminal of the first multi-port interconnection module and the neutral terminal of the third multi-port interconnection module. The AC sides of these three multi-port interconnection modules are used to access single-phase high-voltage AC, and this multi-port interconnection system can realize the interconnection between a single-phase high-voltage AC and multiple DCs.

[0089] Exemplarily, the second AC-DC converter in the multi-port interconnection module of the multi-port interconnection system can be directly connected to a load or a DC input, or the second AC-DC converters are connected in series and then connected to a load or a DC input.

[0090] Exemplarily, the second AC-DC converter of the multi-port interconnection module in the multi-port interconnection system at least includes a single-phase three-level topology and a center-tapped full-wave rectifier topology. The single-phase three-level topologies of multiple multi-port interconnection modules in the multi-port interconnection system can be connected in parallel and then connected to a load or a DC input. The center-tapped full-wave rectifier topologies of multiple multi-port interconnection modules in the multi-port interconnection system can be connected in parallel and then connected to a load or a DC input.

[0091] An embodiment of the present application further provides a multi-port interconnection system, including: at least three multi-port interconnection modules as described in the above embodiment; 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 a plurality of 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 for accessing three-phase alternating current.

[0092] In this embodiment, an example is given where the multi-port interconnection module includes three first AC-DC converters, three first DC-AC converters, and two second AC-DC converters for illustration:

[0093] The coupling transformer of the multi-port interconnection module includes three first windings and two second windings. The three first windings are correspondingly connected to the three first DC-AC converters, and the first winding is connected to the AC side of the first DC-AC converter. The DC side of the first DC-AC converter is connected to the DC side of the first AC-DC converter. The two second windings are correspondingly connected to the two second AC-DC converters, and the second winding is connected to the AC side of the second AC-DC converter.

[0094] The three first AC-DC converters in the multi-port interconnection module are connected in series. That is to say, 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.

[0095] As Figure 14As shown, the neutral terminals on the first winding side of the three multi-port interconnection modules in the multi-port interconnection system are connected in parallel. Thus, in the embodiments of the present application, the input terminals on the first winding side of the multi-port interconnection system only include the live terminals of the first multi-port interconnection module, the live terminals of the second multi-port interconnection module, the live terminals of the third multi-port interconnection module, and the neutral terminal after parallel connection. The three live terminals and the neutral terminal after parallel connection on the first winding side of the multi-port interconnection system can be used to access a three-phase alternating current. This multi-port interconnection system can achieve the interconnection of a three-phase alternating current and multiple direct currents.

[0096] Exemplarily, the second AC-DC converter of the multi-port interconnection module in the multi-port interconnection system can be directly connected to a load or a DC input, or the second AC-DC converters can be connected in series and then connected to a load or a DC input.

[0097] Exemplarily, the second AC-DC converter of the multi-port interconnection module in the multi-port interconnection system at least includes a single-phase three-level topology and a center-tapped full-wave rectifier topology. The single-phase three-level topologies of multiple multi-port interconnection modules in the above multi-port interconnection system can be connected in parallel and then connected to a load or a DC input. The center-tapped full-wave rectifier topologies of multiple multi-port interconnection modules in the above multi-port interconnection system can be connected in parallel and then connected to a load or a DC input.

[0098] It should be noted that in this article, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or system. Without further limitations, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or system including that element.

[0099] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-described embodiment methods can be implemented by means of software plus a necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disc) as described above, and includes several instructions for causing a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in various embodiments of the present application.

[0100] The above are only the preferred embodiments of the present application, and do not limit the patent scope of the present application accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present application.

Claims

1. A multi-port interconnection module, characterized in that, the multi-port interconnection module includes: a coupling transformer, the coupling transformer includes a plurality of first windings and a plurality of second windings, and the first windings and the second windings are distributed on different sides of the coupling transformer; a plurality of first DC-AC converters, the AC sides of the plurality of first DC-AC converters are correspondingly connected to the plurality of first windings; a plurality of second AC-DC converters, 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 topologies.

2. The multi-port interconnection module according to claim 1, characterized in that, the two different topologies include: a single-phase three-level topology and a center-tapped full-wave rectifier topology.

3. The multi-port interconnection module according to claim 1 or 2, characterized in that, the first DC-AC converter adopts a single-phase three-level topology.

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

5. The multi-port interconnection module according to claim 4, characterized in that, the pulses of the switching tubes symmetric with respect to the midpoint position of the four switching tubes in the single-phase three-level topology are complementary.

6. The multi-port interconnection module according to claim 4, characterized in that, 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, characterized in that, the pulses of the switching tubes connecting the same-named terminals of the coupling transformer in the single-phase three-level topology and the center-tapped full-wave rectifier topology are the same.

8. The multi-port interconnection module according to claim 1, characterized in that , the multi-port interconnection module further 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 interconnection module according to claim 8, characterized in that, 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 line terminal and a live line terminal; the neutral line 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 interconnection module according to claim 8, characterized in that, 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 line terminal and a live line 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, characterized in that, 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, characterized in that, the number of turns of the plurality of first windings is the same, the number of turns of the plurality of second windings is different, 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, characterized in that, comprising: at least two multi-port interconnection modules according to any one of the above 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 interconnection module are connected in series; the AC sides of at least two of the multi-port interconnection modules are connected in series, and the AC sides of at least two of the multi-port interconnection modules are used to access single-phase high-voltage alternating current.

14. A multi-port interconnection system, characterized in that, comprising: at least three multi-port interconnection modules according to any one of the above 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 interconnection module are connected in series; the neutral terminals of the AC sides of at least three of the multi-port interconnection modules are connected in parallel, and the AC sides of at least three of the multi-port interconnection modules are used to access three-phase alternating current.

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