Modular switch unit

Abstract

The invention relates to a modular switching unit of a high-voltage direct-current power converter, comprising a base module (18) with a first switching device (2), a second switching device (3), a first capacitor (4) and a second capacitor (5), wherein the first switching device (2), the second switching device (3), the first capacitor (4) and the second capacitor (5) are mounted on a chassis (15), characterized in that the base module (18) is adapted to receive at least three different busbar sets, each busbar set comprising a plurality of busbars for interconnecting the first switching device (2), the second switching device (3), the first capacitor (4) and the second capacitor (5) to form one of two parallel half-bridge circuits between a first unit terminal and a second unit terminal, two series half-bridge circuits between the first unit terminal and the second unit terminal (200) and a full-bridge circuit between the first unit terminal and the second unit terminal.

Description

Technical Field

[0001] This invention relates to modular switching units. Specifically, the switching unit includes a base module, which can be constructed by connecting the terminals of the base module in different ways via pre-formed busbars to achieve different unit module types. The invention also relates to a system including the modular switching unit and corresponding busbars. Finally, the invention relates to a method for manufacturing modular switching units. Background Technology

[0002] Multilevel modular converters (MMCs) are known from existing technologies. MMCs are a standard approach in the power converter industry for implementing high-voltage direct current (HVDC) converters for power transmission. They are also widely used in medium-voltage (MV) drive applications—including distribution applications such as static var compensators (STATCOMs).

[0003] Multilevel modular converters consist of multiple units connected in series to form phase arms; depending on the application, one or two units may be used for each phase. Traditional multilevel modular converter units are half-bridges or full-bridges; half-bridge units block voltage in one direction, while full-bridge units block voltage in both directions. Multilevel modular converter units typically include insulated-gate bipolar transistors (IGBTs).

[0004] Within a family of converter manufacturers, there may be a range of overall converter currents and voltage ratings to accommodate a wide range of applications. If many units are placed in series to achieve the required voltage rating, accommodating different ratings is intuitive; however, the converter's rated current typically falls within the range of the individual unit's rated current. Therefore, to generate a range of converter rated currents, either a range of different unit designs are needed, each with a different rated current, or the unit's rated current is not fully utilized in low-current converter designs, resulting in higher cost per kilowatt.

[0005] Traditional multilevel modular converter unit designs are available in the public domain. Many are described in the following literature:

[0006] K. Sharifabadi, L. Harnefors, H.H. Nee, S. Norrga, and R. Teodorescu, “Design, Control, and Application of Modular Multilevel Converters for HVDC Transmission Systems,” John Wiley & Sons / IEE, 2016.

[0007] M. Merlin's slides 16-18, "High Voltage Direct Current Activities at Imperial College London," 2015.

[0008] Alstom Power Grids / GE Power Grids Reference: C. Barker, HVDC Plenary Session, IEEE EPEC 2011.

[0009] C. Bartzsch, H. Huang, T. Westerweller, and M. Davies, “Enhanced High Voltage Direct Current (HVDCPLUS) and Enhanced Static Var Compensator (SVCPLUS): Reliable and Cost-effective Power Transmission Solutions with Modular Multilevel Converters,” 2011.

[0010] The problem with the aforementioned existing technology is that the cell design is highly optimized for a specific topology and rated current. For example, optimization for a specific rated current affects the selection of the insulated gate bipolar transistor (IGBT) / diode module, cell capacitor, and bypass switch. The rated current is typically given as a share of a predetermined current value. For example, a full-rated cell can carry the entire predetermined current. A half-rated cell can only carry half of the predetermined current. While theoretically a half-rated cell could halve the size, the availability of components makes this impossible, for example, when the IGBT module is only available where it is suitable for a full-rated cell. Even if half-rated cell components are available, each half-rated cell still requires the same amount of control components (i.e., cell controller, current / voltage sensor, cell power supply, etc.) as a full-rated cell, and thus requires mechanical components of similar cost and size. Due to the different sizes, the rack support structure for multiple cells will also differ. Therefore, a half-rated cell will be significantly more expensive and larger than half the size of a full-rated cell, resulting in a more expensive (€ / kW) and lower power density (kW / m²) multilevel modular converter. 3 Furthermore, semi-rated units will require separate design, resulting in associated engineering costs.

[0011] This lack of flexibility is also evident if a full-bridge unit is required. Unless half-rated unit components are available, a half-rated full-bridge unit will similarly require a separate design, resulting in associated engineering costs. Summary of the Invention

[0012] Therefore, the problem to be solved is to find a low-cost, high-power-density switching unit that can be used in different topologies and rated currents. This objective is achieved by the features of the independent claims. The dependent claims contain advantageous embodiments of the invention.

[0013] In particular, this invention describes a universal unit design that uses the same basic mechanical design for a full-rated unit or two half-rated units in series, wherein the latter produces the same cost per unit rated power and power density cost as the full-rated unit. These can share a common master design, thereby simplifying the design process and resulting in a lower-cost system.

[0014] This invention specifically addresses this issue through a modular switching unit of a high-voltage DC power converter, comprising a base module. This base module includes a first switching device, a second switching device, a first capacitor, and a second capacitor. These components—namely, the first switching device, the second switching device, the first capacitor, and the second capacitor—are all mounted on a chassis. In this manner, the base module allows for different interconnections of the components to achieve different designs. The first and second switching devices preferably comprise insulated-gate bipolar transistors.

[0015] The basic module is adapted to receive at least three different bus groups, each bus group including multiple buses for interconnecting a first switching device, a second switching device, a first capacitor, and a second capacitor. Each bus group allows for different designs of the basic module. Specifically, one bus group allows for the formation of two parallel half-bridge circuits between the first unit terminals and the second unit terminals. Furthermore, another bus group allows for the formation of two series half-bridge circuits between the first unit terminals and the second unit terminals. Yet another bus group allows for the formation of a full-bridge circuit between the first unit terminals and the second unit terminals. Thus, each bus group interconnects the aforementioned components of the basic module in a different manner. Therefore, the basic module can be used for different unit types, particularly for different rated currents and topologies. Consequently, this modular switching unit is inexpensive and allows for high power density.

[0016] Therefore, this invention provides a universal unit design that uses the same basic mechanical design, namely, a base module, for a full-rated unit or two half-rated units in series, wherein the latter produces the same cost per unit rated power and power density cost as the full-rated unit. These unit types share a common master design, thereby simplifying the design process and resulting in a lower-cost system.

[0017] Preferably, the first switching device has a first AC voltage terminal, a first negative DC terminal, a first positive DC terminal, a first switch between the first AC voltage terminal and the first negative DC terminal, and a second switch between the first AC voltage terminal and the first positive DC terminal. In this manner, the first switching device is specifically configured as a half-bridge module. Further, the second switching device preferably has a second AC voltage terminal, a second negative DC terminal, a second positive DC terminal, a third switch between the second AC voltage terminal and the second negative DC terminal, and a fourth switch between the second AC voltage terminal and the second positive DC terminal. Again, the second switching device is specifically configured as a half-bridge module. The base module is adapted to receive each bus group such that the buses in each bus group interconnect all terminals of the first and second switching devices, as well as the first and second capacitors. In this manner, specifically, the first AC voltage terminal, the first negative DC terminal, the first positive DC terminal, the second AC voltage terminal, the second negative DC terminal, the second positive DC terminal, the first capacitor, and the second capacitor are interconnected. The buses are provided such that they form one of two parallel half-bridge circuits, two series half-bridge circuits, and a full-bridge circuit. Therefore, in cases where different circuits must be provided, only the busbars must be different. Thus, a single basic module can be used to implement a wide variety of power converters.

[0018] In a preferred embodiment, at least the first negative DC terminal is electrically connected to the chassis. The chassis is preferably used as a chassis ground. Depending on the unit design defined by the busbar group, a second positive DC terminal or a second negative DC terminal is also preferably connected to the chassis. Preferably, all switching devices share the same chassis ground, such that, particularly in modular switching units, only a single chassis ground potential exists.

[0019] More preferably, the first and second switches of the first switching device, and the third and fourth switches of the second switching device, all comprise electronic switches. The electronic switches specifically include insulated-gate bipolar transistors (IGBTs) and diodes wired in parallel with each other. Instead of IGBTs, other electronic switches can be used, such as integrated gate-commutated thyristors (IGCTs), gate-turn-off thyristors (GTOs), metal-oxide-semiconductor field-effect transistors (MOSFETs), high electron mobility transistors (HEMTs), or bipolar junction transistors (BJTs). All these components can be combined in different ways—i.e., via different bus groups—to realize different modular switching units and thus power converters.

[0020] The modular switching unit preferably includes a single control device. This control device is suitable for switching the first and second switches of the first switching device and the third and fourth switches of the second switching device. In this way, the power input to the modular switching unit can be optimally converted, and the converted power is output. Thus, it is preferable that the single control device performs overall control of all switches.

[0021] More preferably, the first switching device includes a first sub-switching device and a second sub-switching device. In this case, the first and second switching devices are not half-bridge modules (e.g., half-bridge insulated-gate bipolar transistors), but single switching modules (e.g., insulated-gate bipolar transistors). Preferably, the first sub-switching device includes a first AC voltage terminal, a first negative DC terminal, and a first switch. Preferably, the second sub-switching device includes a first AC voltage terminal, a first positive DC terminal, and a second switch. Therefore, the interconnection of the first switching elements can still be done via a busbar, wherein the two sub-switching devices must be connected separately. Similarly, the second switching device preferably includes a third sub-switching device and a fourth sub-switching device. The third sub-switching device has a second AC voltage terminal, a second negative DC terminal, and a third switch. On the other hand, the fourth sub-switching device has a second AC voltage terminal, a second positive DC terminal, and a fourth switch. Therefore, the second switching device also includes two sub-switching devices, which will be connected separately via a busbar.

[0022] A further preferred embodiment is the provision of a heat sink. This heat sink is specifically provided for cooling more than one switching device. Preferably, the first switching device, the second switching device, the first capacitor, and the second capacitor are provided with a common heat sink. Therefore, the power density of the unit is increased, and the cost of providing the unit is reduced.

[0023] Modular switching units, in particular, have a bypass switch disposed between the first unit terminal and the second unit terminal. The bypass switch is adapted to bypass the switching unit by shorting the first and second unit terminals. In the case of establishing a converter with the modular switching unit as described above, the bypass switch allows, for example, the corresponding switching unit to be unused in the event of a switch unit failure. Therefore, a failure of one switching unit does not necessarily lead to a failure of the entire converter. In an alternative embodiment, the bypass switch is omitted, and the components of the switching unit are adapted to short-circuit the first and second unit terminals in the event of a component failure.

[0024] In another advantageous embodiment, the first switching device, the second switching device, the first capacitor, and the second capacitor can all be electrically connected from the same side via a busbar assembly. Therefore, the busbar assembly only needs to be arranged on one side of the base module to interconnect all components. Thus, different unit designs, particularly the unit design described above, can be provided in a simplified manner.

[0025] The present invention also relates to a system comprising the modular switching unit as described above, and at least two of a first bus group, a second bus group, and a third bus group. Therefore, the system can be configured to provide different unit designs. Preferably, a converter can be built from several of these systems. In this system, a first capacitor is disposed between a first capacitor terminal and a second capacitor terminal, and a second capacitor is disposed between a third capacitor terminal and a fourth capacitor terminal. All these capacitor terminals can be connected via buses in the bus groups to connect the switching device to the capacitors. Different designs can be provided using different bus groups, wherein these different bus groups are now described:

[0026] The first busbar group includes a first busbar, a second busbar, and a third busbar. The first busbar electrically connects a first negative DC terminal and a second negative DC terminal, as well as a second capacitor terminal and a fourth capacitor terminal. The second busbar electrically connects a first positive DC terminal and a second positive DC terminal, as well as a first capacitor terminal and a third capacitor terminal. Finally, a first AC voltage terminal and a second AC voltage terminal are electrically connected via the third busbar. In this unit design, the first busbar is the second unit terminal, and the third busbar is the first unit terminal. Therefore, the first busbar group preferably defines a fully rated half-bridge unit. This means that the switching devices are half-rated and connected in parallel via the first busbar group. Thus, the unit design is a half-bridge, and each switching device specifically carries half of the current flowing through each unit.

[0027] In an additional or alternative embodiment, the second busbar group includes a fourth busbar, a fifth busbar, a sixth busbar, a seventh busbar, and an eighth busbar. The fourth busbar is electrically connected to a first AC voltage terminal. The fifth busbar is electrically connected to a first positive DC terminal and a first capacitor terminal. A second negative DC terminal and a fourth capacitor terminal are electrically connected via the sixth busbar. The seventh busbar is electrically connected to the first negative DC terminal and the second positive DC terminal, and to a second capacitor terminal and a third capacitor terminal. Finally, the eighth busbar is electrically connected to a second AC voltage terminal. According to this unit design, the fourth busbar is a first unit terminal, and the eighth busbar is a second unit terminal. This unit design provides a half-rated dual unit. This means that two switching devices are connected in series, enabling the unit to function as two half-rated units.

[0028] In another additional or alternative embodiment, the third bus group includes the second bus, the fourth bus, the eighth bus, and the ninth bus as described above. The ninth bus is electrically connected to the first negative DC terminal and the second negative DC terminal, as well as the second capacitor terminal and the fourth capacitor terminal. This unit design achieves a half-rated full bridge. Therefore, the switching devices are connected such that they form a full bridge. In particular, as described above, each switching device is a half-bridge module, such that these half-bridge modules are combined through the third bus group to form a full bridge.

[0029] Therefore, from the same basic module—that is, from the same switching devices and capacitors—at least three different unit designs can be produced simply by combining the basic module with one of the first bus group, the second bus group, and the third bus group. This allows for increased flexibility in providing different unit types and / or converters.

[0030] Advantageously, the buses in each bus group are laminated buses. By providing laminated buses, the space required for interconnecting switching devices and capacitors is reduced. Furthermore, electrical performance is enhanced, for example, stray inductance is reduced.

[0031] Each busbar group includes a busbar defining a first unit terminal and a second unit terminal, the first and second unit terminals being arranged for electrical connection of the switching unit to other components, particularly to other switching units of the power converter. Therefore, in order to establish the converter, each unit is connected via a corresponding busbar forming the unit terminal.

[0032] The present invention also relates to a high-voltage direct current power converter. The converter includes a three-phase voltage input terminal, and for each phase of the three-phase voltage input terminal, provides a plurality of switching units as described above. These switching units are connected in series. Therefore, the power converter can be configured with the flexible and low-cost switching units as described above, wherein the switching units, in particular, have high energy density.

[0033] Finally, this invention relates to a method of manufacturing a modular switching unit. The method includes the following steps: on one hand, providing a base module by mounting a first switching device, a second switching device, a first capacitor, and a second capacitor on a chassis. This base module is adapted to receive different bus groups to achieve different unit designs. Therefore, at least two different bus groups are provided. Each group includes multiple buses for interconnecting the first switching device, the second switching device, the first capacitor, and the second capacitor. The buses in each bus group are adapted to form one of two parallel half-bridge circuits between the first unit terminals and the second unit terminals, two series half-bridge circuits between the first unit terminals and the second unit terminals, and a full-bridge circuit between the first unit terminals and the second unit terminals. Thus, by interconnecting the elements of the base module in different ways, each bus group allows for another unit design. As a final step, one of the bus groups is mounted on the base element. By mounting the corresponding bus groups on the base element, a switching unit having one of the designs listed above is provided. Since any of these bus groups can be mounted on the base module, this is a simple and flexible way to provide different types of switching units. Attached Figure Description

[0034] Further implementation methods and advantages will become clear from the following description of the accompanying drawings. In the drawings:

[0035] Figure 1 This is a schematic diagram of a high-voltage direct current power converter according to one embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of the output voltage of one phase of a high-voltage DC power converter according to this embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of the half-bridge switching unit of a high-voltage DC power converter according to this embodiment of the present invention.

[0038] Figure 4 This is a schematic diagram of the full-bridge switching unit of a high-voltage DC power converter according to this embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of a switching unit according to an embodiment of the present invention.

[0040] Figure 6 This is a schematic diagram of the basic module of the switching unit according to this embodiment of the present invention.

[0041] Figure 7 This is a schematic diagram of a first alternative to the switching unit according to this embodiment of the present invention.

[0042] Figure 8This is a schematic wiring diagram of a first alternative to the switching unit according to this embodiment of the present invention.

[0043] Figure 9 This is a schematic diagram of a second alternative to the switching unit according to this embodiment of the present invention.

[0044] Figure 10 This is a schematic wiring diagram of a second alternative to the switching unit according to this embodiment of the present invention.

[0045] Figure 11 This is a schematic diagram of a third alternative to the switching unit according to this embodiment of the present invention.

[0046] Figure 12 This is a schematic wiring diagram of a third alternative to the switching unit according to this embodiment of the present invention.

[0047] Figure 13 This is a schematic diagram of a switching unit according to another embodiment of the present invention, and

[0048] Figure 14 This is a schematic wiring diagram of the switching unit in another alternative solution. Detailed Implementation

[0049] Figure 1 This is a schematic diagram of a high-voltage direct current converter 20, specifically used for power transmission. The high-voltage direct current power converter 20 includes three-phase voltage input terminals 600 and is adapted to output DC voltage. For each phase of the three-phase voltage input terminals 600, multiple switching units 1 are connected in series. For example... Figure 2 As shown, the phase output voltage 300 can therefore be divided into multiple unit voltages 400 of these individual switching units 1. By performing corresponding switching by the switching units 1, the phase output voltage 300 can be converted into a DC voltage.

[0050] Figure 3 and Figure 4 Different unit types of switch unit 1 are shown. All switch units 1 are disposed between the first unit terminal 100 and the second unit terminal 200. Figure 3 The image shows a half-bridge, while Figure 4 A full bridge is shown. A half bridge can only block current in one direction, while a full bridge can block current in both directions. Therefore, Figure 3 The half-bridge design shown uses only a single first switching device 2 as the switching unit 1. On the other hand, according to Figure 4 The shown full-bridge design switching unit 1 has a first switching device 2 and a second switching device 3. In this embodiment, both the first switching device 2 and the second switching device 3 are half-bridge elements. Therefore, the two half-bridge elements of the first switching device 2 and the second switching device 3 are combined together to form... Figure 4 The entire bridge in the middle.

[0051] Therefore, each of the switching devices 2 and 3 has two insulated-gate bipolar transistors 80 and two diodes 90. One insulated-gate bipolar transistor 80 and one diode 90 are connected in parallel, and the two sets of parallel insulated-gate bipolar transistors 80 and diodes 90 are connected in series. In this way, the aforementioned half-bridge element is formed.

[0052] Each switching unit 1 also includes at least a first capacitor 4. The first capacitor 4 is connected in parallel with the switching devices 2 and 3. Therefore, each switching unit 1 divides the phase output voltage 300 into several unit voltages 400 between the first unit terminal 100 and the second unit terminal 200 of the corresponding switching unit 1, so that the switching unit 1 can be used to convert the phase output voltage 300 into a DC voltage.

[0053] A bypass switch 19 can be provided to allow current to bypass the switching unit 1 in the event of a unit failure, thereby maintaining the operation of the converter 20. This can be achieved using a combination of thyristors, mechanical contactors, or fast-acting pyrotechnic devices. If the semiconductor switches used in the unit do not short-circuit, the bypass switch 19 may not be necessary, for example, in the case of specially designed press-fit insulated-gate bipolar transistors or integrated gate-commutated thyristors (IGCTs).

[0054] Figure 5 This is a schematic diagram of a switching unit 1 according to an embodiment of the present invention. The switching unit 1 includes, as shown below... Figure 3 and Figure 4 The first switching device 2 and the second switching device 3, as well as the first capacitor 4 and the second capacitor 5, are shown. Figure 5 The diagram shows a first switching device 2, a second switching device 3, a first capacitor 4, and a second capacitor 5 mounted on a common chassis 15. The two switching devices 2 and 3 also share the same heat sink 17, so that switching unit 1 has only a single inlet 17a and outlet 17b for coolant. Switching unit 1 also has a shared control device 16, which specifically drives the insulated-gate bipolar transistors 80 of switching devices 2 and 3. Therefore, switching unit 1 has a higher energy density compared to two single units with only one switching device. Furthermore, since all components are mounted on the same chassis 15, chassis 15 serves as a common chassis ground.

[0055] Switching unit 1 does not have a fixed unit design. Instead, switching unit 1 can be constructed with different unit designs, providing flexibility in providing converters 20 with different requirements. To allow for different unit designs, switching unit 1 has a base module 18, which includes a first switching device 2, a second switching device 3, a first capacitor 4, and a second capacitor 5. Base module 18 is also adapted to receive different bus groups. Each bus group connects the components of base module 18 in a different manner to achieve different unit designs.

[0056] Preferably, all the busbars in the busbar group contact the components of the base module 18 from the same side. Therefore, the installation of the busbar group and the electrical connections of the first switching device 2, the second switching device 3, the first capacitor 4, and the second capacitor 5 are simplified.

[0057] For electrical contact with the busbar group, the first switching device 2 has a first AC voltage terminal 21, a first negative DC terminal 22, and a first positive DC terminal 23. The first switch is disposed between the first AC voltage terminal 21 and the first negative DC terminal 22, while the second switch is disposed between the first AC voltage terminal 21 and the first positive DC terminal 23. The two switches are composed of the aforementioned insulated-gate bipolar transistor 80 and diode 90 connected in parallel.

[0058] Similarly, the second switching device 3 has a second AC voltage terminal 31, a second negative DC terminal 32, and a second positive DC terminal 33. A third switch is disposed between the second AC voltage terminal 31 and the second negative DC terminal 32, while a fourth switch is disposed between the second AC voltage terminal 31 and the second positive DC terminal 33. Likewise, these two switches—the third and fourth switches—are composed of the aforementioned parallel insulated-gate bipolar transistor 80 and diode 90.

[0059] The first capacitor 4 is disposed between the first capacitor terminal 41 and the second capacitor terminal 42, while the second capacitor 5 is disposed between the third capacitor terminal 51 and the fourth capacitor terminal 52. Preferably, all of the above terminals are located on the same side of the switching unit 1 to ensure that the switching unit 1 can be electrically contacted from one side via the busbar group.

[0060] Starting from this basic design, the switching unit 1 can be configured with different unit designs. In particular, the two switching devices 3 and 4 can be connected in parallel to increase the rated current or form a full bridge. The switching devices 3 and 4 can also be placed in series to form a dual-switching unit consisting of two conventional switching units. Three different designs are shown below, all implemented using the same basic module 18 through different bus groups.

[0061] exist Figure 7 and Figure 8The image shows two parallel half-bridge circuits between the first unit terminal 100 and the second unit terminal 200. Figure 7 The design of switch unit 1 is schematically shown, while Figure 8 A schematic wiring diagram is shown. Figure 9 and Figure 10 The image shows two series half-bridge circuits between the first unit terminal 100 and the second unit terminal 200. Figure 9 The design of switch unit 1 is schematically shown, while Figure 10 A schematic wiring diagram is shown. Finally, the full-bridge circuit between the first unit terminal 100 and the second unit terminal 200 is... Figure 11 and Figure 12 As shown in the image. Figure 11 The design of switch unit 1 is schematically shown, while Figure 12 A schematic wiring diagram is shown.

[0062] According to Figure 7 and Figure 8 In the design, the first bus group, including the first bus 6, the second bus 7 and the third bus 8, is used to interconnect the first AC voltage terminal 21, the first negative DC terminal 22, the first positive DC terminal 23, the second AC voltage terminal 31, the second negative DC terminal 32, the second positive DC terminal 33, the first capacitor terminal 41, the second capacitor terminal 42, the third capacitor terminal 51 and the fourth capacitor terminal 52.

[0063] The first negative DC terminal 22 and the second negative DC terminal 32, as well as the second capacitor terminal 42 and the fourth capacitor terminal 52, are electrically connected via the first busbar 6. The first positive DC terminal 23 and the second positive DC terminal 33, as well as the first capacitor terminal 41 and the third capacitor terminal 51, are electrically connected via the second busbar 7. The third busbar 8 electrically connects the first AC voltage terminal 21 and the second AC voltage terminal 31. In this design, the first busbar 6 is the second unit terminal 200, and the third busbar 8 is the first unit terminal 100.

[0064] Specifically, such as Figure 8 As shown, the first switching device 2, the second switching device 3, the first capacitor 4, and the second capacitor 5 are connected in parallel. Therefore, because the parallel connection of the components doubles the current that the switching unit can carry, the switching unit 1 is a fully rated half-bridge. A common chassis ground is provided through the chassis 15 at the first negative DC terminal 22 and the second negative terminal 23, which are identical in this design.

[0065] The same basic module 18 can be configured with Figure 9 and Figure 10The different second bus groups shown form a half-rated dual unit. The second bus groups include a fourth bus 9, a fifth bus 10, a sixth bus 11, a seventh bus 12, and an eighth bus 13, which interconnect a first AC voltage terminal 21, a first negative DC terminal 22, a first positive DC terminal 23, a second AC voltage terminal 31, a second negative DC terminal 32, a second positive DC terminal 33, a first capacitor terminal 41, a second capacitor terminal 42, a third capacitor terminal 51, and a fourth capacitor terminal 52.

[0066] The first AC voltage terminal 21 is electrically connected to the fourth bus 9. The first positive DC terminal 23 and the first capacitor terminal 41 are electrically connected via the fifth bus 10. The second negative DC terminal 32 and the fourth capacitor terminal 52 are electrically connected via the sixth bus 11. The seventh bus 12 electrically connects the first negative DC terminal 22 and the second positive DC terminal 33, as well as the second capacitor terminal 42 and the third capacitor terminal 51. Finally, the second AC voltage terminal 31 is electrically connected to the eighth bus 13. In this unit design, the fourth bus 9 is the first unit terminal 100, and the eighth bus 13 is the second unit terminal 200. Therefore, the first switching device 2 and the first capacitor 4 form a half-rated half-bridge, which is connected in series with another half-rated half-bridge formed by the second switching device 3 and the second capacitor 5. In particular, the two half-rated half-bridges are formed as mirror images of each other, so that they can share the same power supply and controller. A common chassis ground is provided by the chassis 15 at the first negative DC terminal 22 and the second positive DC terminal, which are identical in this design.

[0067] exist Figure 9 and Figure 10 In the design, the unit output voltage is double the unit voltage of 500, which is twice the unit voltage of 400. Therefore, using the same components, one fully rated half-bridge or two half-rated half-bridges can be provided. Thus, based on the corresponding requirements of converter 20, the same base module 18 can be provided as different unit topologies.

[0068] In addition, Figure 9 and Figure 10 In the design, there are two options for the bypass switch 19. Either bypass switch can be used for each of the two half-bridges, with the two bypass switches connected in series and their midpoint also connected to the midpoint between the two half-bridges; or a single bypass switch can be used for the entire switching unit 1. If two bypass switches are used, each bypass switch requires the same rated voltage as in the case of a single switching unit 1. However, using a single bypass switch for the entire switching unit 1 requires a higher rated voltage because bypass switch 19 must carry twice the unit voltage 400, or 500.

[0069] at last, Figure 11 and Figure 12 A half-rated full-bridge design is illustrated. In this design, two switching devices 2 and 3, forming a half-bridge module, are combined to establish a full bridge. To achieve this design, a third busbar group includes the aforementioned second busbar 7, fourth busbar 9, eighth busbar 13, and an additional ninth busbar 14. The ninth busbar 14 electrically connects the first negative DC terminal 22 and the second negative DC terminal 32, as well as the second capacitor terminal 42 and the fourth capacitor terminal 52. The chassis 15 provides a common chassis ground at the first negative DC terminal 22 and the second negative DC terminal 32.

[0070] The buses in each bus group are advantageously laminated buses. This particularly helps to reduce stray inductance between the insulated gate bipolar transistor 80 and capacitors 4 and 5, ensuring optimal switching of the switching unit 1.

[0071] Therefore, in addition to the full-rated half-bridge and the dual half-rated half-bridge, the base module 18 can also be provided with another bus group to form a half-rated full-bridge. In this way, a variety of different unit options can be provided by a single base module 18.

[0072] Figure 13 It shows the relationship with Figure 7 The switching unit 1 shown has the same unit design, but uses different first switching devices 2 and second switching devices 3. In the above embodiment, the first switching device 2 and the second switching device 3 are described as a half-bridge module. Figure 13 As shown, another setup using a single switch module can also be adopted.

[0073] Therefore, the first switching device 2 includes a first sub-switching device 2a and a second sub-switching device 2b. The first sub-switching device 2a has a first AC voltage terminal 21, a first negative DC terminal 22, and a first switch disposed between the first AC voltage terminal 21 and the first negative DC terminal 22. The second sub-switching device 2b also has a first AC voltage terminal 21 and further includes a first positive DC terminal 23 and a second switch disposed between the first AC voltage terminal 21 and the first positive DC terminal 23. Similarly, the second switching device 3 includes a third sub-switching device 3a and a fourth sub-switching device 3b. The third sub-switching device 3a has a second AC voltage terminal 31, a second negative DC terminal 32, and a third switch disposed between the second AC voltage terminal 31 and the second negative DC terminal 32. The fourth sub-switching device 3b has a second AC voltage terminal 31, a second positive DC terminal 33, and a fourth switch disposed between the second AC voltage terminal 31 and the second positive DC terminal 33. Therefore, the sub-switching devices 2a, 2b, 3a, and 3b must be in contact with the first busbar 6, the second busbar 7, and the third busbar 8 respectively, wherein the unit design maintains contact with... Figure 7The same as shown. The arrangement of these switching devices 2 and 3—that is, the use of sub-switching devices 2a, 2b, 3a, and 3b—can be applied to any other unit design, particularly to… Figure 9 and Figure 11 The design shown.

[0074] at last, Figure 14 Another design option for switching devices 2 and 3 is shown. In this design option, switching devices 2 and 3 are provided as multi-level bridge arms with three levels. To achieve this design, an additional diode 90 is included in each switching device 2 and 3.

[0075] In summary, the switching unit 1 described above can be used for different purposes, and all switching units 1 share the same basic components. Therefore, the same hardware can always be used to provide various different switching units 1 for the converter 20. The cost of the switching unit 1 is low because only one set of control components (e.g., control unit 16 and heat sink 17) must be provided. The switching unit 1 enables maximum component reuse and design reuse. Furthermore, a compact unit design is provided, particularly in the case of a dual-unit configuration including two half-rated half-bridges. Reliability is improved due to the reduced number of components, coolant, and electrical connections.

[0076] Figure Labels

[0077] 1. Switching unit 100. First unit terminal.

[0078] 2 First switching device 200 Second unit terminal

[0079] 21 First AC voltage terminal 300 phase output voltage

[0080] 22 First negative DC terminal 400 unit voltage

[0081] 23 First positive DC terminal 500 dual-unit voltage

[0082] 3. Second switching device 600 Three-phase voltage input terminal

[0083] 31 Second AC voltage terminal

[0084] 32 Second negative DC terminal

[0085] 33 Second positive DC terminal

[0086] 4 First capacitor

[0087] 41 First capacitor terminal

[0088] 42 Second capacitor terminal

[0089] 5 Second capacitor

[0090] 51 Third capacitor terminal

[0091] 52 Fourth capacitor terminal

[0092] 6 First busbar

[0093] 7 Second busbar

[0094] 8 Third busbar

[0095] 9. Fourth busbar

[0096] 10 Fifth busbar

[0097] 11. Sixth busbar

[0098] 12 Seventh busbar

[0099] 13 Eighth busbar

[0100] 14 Ninth busbar

[0101] 15 Chassis

[0102] 16. Control device

[0103] 17 Radiator

[0104] 17a Entrance

[0105] 17b Export

[0106] 18 Basic Modules

[0107] 19 Bypass switch

[0108] 20 Converter devices

[0109] 80 Insulated Gate Bipolar Transistor

[0110] 90 diode

Claims

1. A modular switching unit (1) for a high-voltage DC power converter (20), comprising a base module (18), the base module having: • First switching device (2). • Second switching device (3). • First capacitor (4), and • Second capacitor (5) in, The first switching device (2), the second switching device (3), the first capacitor (4), and the second capacitor (5) are mounted on the chassis (15). The basic module (18) is characterized in that it is adapted to receive at least three different bus groups, each bus group comprising multiple buses (6, 7, 8, 9, 10, 11, 12, 13, 14), for interconnecting the first switching device (2), the second switching device (3), the first capacitor (4), and the second capacitor (5) to form one of the following by mounting one of the at least three different bus groups on the basic module: • Two parallel half-bridge circuits between the first unit terminal (100) and the second unit terminal (200), and • Two series half-bridge circuits between the first unit terminal (100) and the second unit terminal (200), and • A full-bridge circuit between the first unit terminal (100) and the second unit terminal (200).

2. The modular switching unit (1) according to claim 1, characterized in that, • The first switching device (2) has a first AC voltage terminal (21), a first negative DC terminal (22), a first positive DC terminal (23), a first switch located between the first AC voltage terminal (21) and the first negative DC terminal (22), and a second switch located between the first AC voltage terminal (21) and the first positive DC terminal (23). • The second switching device (3) has a second AC voltage terminal (31), a second negative DC terminal (32), a second positive DC terminal (33), a third switch located between the second AC voltage terminal (31) and the second negative DC terminal (32), and a fourth switch located between the second AC voltage terminal (31) and the second positive DC terminal (33), and • The base module (18) is adapted to receive each bus group such that the buses (6, 7, 8, 9, 10, 11, 12, 13, 14) in the corresponding bus group interconnect the first AC voltage terminal (21), the first negative DC terminal (22), the first positive DC terminal (23), the second AC voltage terminal (31), the second negative DC terminal (32), the second positive DC terminal (33), the first capacitor (4) and the second capacitor (5) to form one of the two parallel half-bridge circuits, the two series half-bridge circuits and the full-bridge circuit.

3. The modular switching unit (1) according to claim 2, characterized in that, At least the first negative DC terminal (22) is electrically connected to the chassis (15), wherein the chassis (15) is used as chassis ground.

4. The modular switching unit (1) according to claim 2 or 3, characterized in that, The first switch and the second switch of the first switching device (2) and the third switch and the fourth switch of the second switching device (3) all include electronic switches.

5. The modular switching unit (1) according to claim 2 or 3, characterized in that, A single control device (16) is adapted to switch the first switch and the second switch of the first switching device (2) and the third switch and the fourth switch of the second switching device (3).

6. The modular switching unit (1) according to claim 2 or 3, characterized in that... , • The first switching device (2) includes a first sub-switching device (2a) and a second sub-switching device (2b). The first sub-switching device (2a) includes the first AC voltage terminal (21), the first negative DC terminal (22), and the first switch, and The second sub-switch device (2b) includes the first AC voltage terminal (21), the first positive DC terminal (23), and the second switch, and • The second switching device (3) includes a third sub-switching device (3a) and a fourth sub-switching device (3b). The third sub-switch device (3a) includes a second AC voltage terminal (31), a second negative DC terminal (32), and a third switch, and The fourth sub-switch device (3b) includes a second AC voltage terminal (31), a second positive DC terminal (33), and a fourth switch.

7. The modular switching unit (1) according to any one of claims 1-3, characterized in that, The first switching device (2), the second switching device (3), the first capacitor (4) and the second capacitor (5) are provided with a common heat sink (17).

8. The modular switching unit (1) according to any one of claims 1-3, characterized in that, A bypass switch (19) is provided between the first unit terminal (100) and the second unit terminal (200), wherein the bypass switch (19) is adapted to bypass the modular switch unit (1).

9. The modular switching unit (1) according to any one of claims 1-3, characterized in that, The first switching device (2), the second switching device (3), the first capacitor (4) and the second capacitor (5) can all be electrically connected from the same side via the busbar group.

10. The modular switching unit (1) according to claim 4, characterized in that, The electronic switch is an insulated gate bipolar transistor (80) and a diode (90) connected in parallel with each other.

11. A system for a high-voltage direct current power converter (20), the system comprising a modular switching unit (1) according to claim 6 and at least two bus groups selected from a first bus group, a second bus group, and a third bus group. in, The first capacitor (4) is disposed between the first capacitor terminal (41) and the second capacitor terminal (42), and the second capacitor (5) is disposed between the third capacitor terminal (51) and the fourth capacitor terminal (52), wherein: • The first busbar group includes the first busbar (6), the second busbar (7), and the third busbar (8), wherein: The first negative DC terminal (22) and the second negative DC terminal (32) are electrically connected to the second capacitor terminal (42) and the fourth capacitor terminal (52) via the first busbar (6). The first positive DC terminal (23) and the second positive DC terminal (33) are electrically connected to the first capacitor terminal (41) and the third capacitor terminal (51) via the second bus (7), and The first AC voltage terminal (21) and the second AC voltage terminal (31) are electrically connected via the third busbar (8). The first busbar (6) is the second unit terminal (200), and the third busbar (8) is the first unit terminal (100). and / or • The second busbar group includes the fourth busbar (9), the fifth busbar (10), the sixth busbar (11), the seventh busbar (12), and the eighth busbar (13), wherein: The first AC voltage terminal (21) is electrically connected to the fourth busbar (9). The first positive DC terminal (23) and the first capacitor terminal (41) are electrically connected via the fifth bus (10). The second negative DC terminal (32) and the fourth capacitor terminal (52) are electrically connected via the sixth bus (11). The first negative DC terminal (22) and the second positive DC terminal (33) are electrically connected to the second capacitor terminal (42) and the third capacitor terminal (51) via the seventh bus (12). The second AC voltage terminal (31) is electrically connected to the eighth bus (13). The fourth busbar (9) is the first unit terminal (100), and the eighth busbar (13) is the second unit terminal (200). and / or • The third busbar group includes the second busbar (7), the fourth busbar (9), the eighth busbar (13), and the ninth busbar (14), wherein: The first negative DC terminal (22) and the second negative DC terminal (32) are electrically connected to the second capacitor terminal (42) and the fourth capacitor terminal (52) via the ninth bus (14).

12. The system according to claim 11, characterized in that, The buses in each bus group (6, 7, 8, 9, 10, 11, 12, 13, 14) are all laminated buses.

13. The system according to claim 11, characterized in that, Each bus group includes a bus (6, 7, 8, 9, 10, 11, 12, 13, 14) defining the first unit terminal (100) and the second unit terminal (200), the first unit terminal (100) and the second unit terminal (200) being arranged for electrically connecting the modular switching unit (1) to other components of the power converter (20).

14. The system according to claim 13, characterized in that, The first unit terminal (100) and the second unit terminal (200) are arranged to electrically connect the modular switching unit (1) to other modular switching units (1) of the power converter (20).

15. A high-voltage DC power converter (20) comprising a three-phase voltage input terminal (600), and for each phase of said three-phase voltage input terminal (600), comprising a plurality of modular switching units (1) according to any one of claims 1 to 10, wherein, The modular switch unit (1) is connected in series.

16. A method for manufacturing a modular switching unit (1), characterized in that, Includes the following steps: • A base module (18) is provided by mounting a first switching device (2), a second switching device (3), a first capacitor (4), and a second capacitor (5) on a chassis (15). • Provide at least two different busbar groups, each busbar group comprising a plurality of buses (6, 7, 8, 9, 10, 11, 12, 13, 14) for interconnecting the first switching device (2), the second switching device (3), the first capacitor (4), and the second capacitor (5), wherein the buses (6, 7, 8, 9, 10, 11, 12, 13, 14) in each busbar group are adapted to form one of the following: Two parallel half-bridge circuits between the first unit terminal (100) and the second unit terminal (200), and Two series half-bridge circuits between the first unit terminal (100) and the second unit terminal (200), and The full-bridge circuit between the first unit terminal (100) and the second unit terminal (200), and • Install one of the bus groups on the base module (18).

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