Low-stress high-margin IGCT-MMC flexible direct current transmission power module

Abstract

The invention discloses a low-stress high-margin IGCT-MMC flexible direct-current transmission power module which comprises a first IGCT device, a second IGCT device, a first diode, a second diode, a third diode, a fourth diode, a first capacitor, a second capacitor, a first resistor, a second resistor, an anode reactor, a direct-current supporting capacitor and a clamping circuit. The clamping circuit comprises a clamping diode, a clamping resistor and a clamping capacitor. According to the invention, the stress of a device switch can be effectively reduced, the safety margin of the power module can be effectively expanded, and the reliability of the power module can be greatly enhanced. The invention can be widely applied to the field of power module circuits.

Description

Technical Field

[0001] The present invention relates to the field of power module circuits, and in particular, to a low-stress and high-margin IGCT-MMC flexible DC transmission power module. Background Art

[0002] Compared with traditional devices (such as IGBTs), IGCTs (Integrated Gate Commutated Thyristors) have shown broad application prospects in the field of flexible DC transmission (VSC-HVDC) due to their significant advantages such as high voltage withstand, low loss, large current, low cost, and high safety. IGCTs can withstand higher voltage and current stresses, and at the same time have lower conduction losses and stronger fault tolerance capabilities, making them highly competitive in large-capacity power transmission scenarios. With the rapid development of flexible DC transmission technology, its engineering applications have gradually shifted from early demonstration projects to large-scale commercial deployments. In this context, the reliability of system operation has become the core concern. Especially when the power grid faces extreme faults (such as DC short circuits, AC asymmetric faults, etc.), how to ensure the continuous and stable operation of the converter equipment and avoid large-scale power outages has become the key research direction. With its fast turn-off ability, high robustness, and easy redundancy design, IGCTs provide key hardware support for improving the fault ride-through ability and uninterrupted operation of flexible DC transmission systems. In the future, combined with intelligent monitoring, advanced control strategies, and new material technologies, IGCTs are expected to further promote the development of flexible DC transmission towards higher reliability and higher efficiency.

[0003] In topologies such as MMC (Modular Multilevel Converter), IGCTs need to switch frequently (from hundreds of Hz to kHz). The rapidly changing di / dt and dv / dt will trigger parasitic parameter oscillations (such as voltage spikes caused by stray inductance), which will exacerbate the dynamic stress of the device. Therefore, how to reduce stress in the power module structure design based on IGCT devices is an important link to exert its electrical advantages. Summary of the Invention

[0004] In view of this, in order to solve the technical problem that the existing flexible DC transmission power module cannot meet the low stress required by the scenario, the present invention proposes a low-stress and high-margin IGCT-MMC flexible DC transmission power module, whose circuit content includes a first IGCT device, a second IGCT device, a first diode, a second diode, a third diode, a fourth diode, a first capacitor, a second capacitor, a first resistor, a second resistor, an anode reactor, a DC support capacitor, a clamping diode, a clamping resistor, and a clamping capacitor, where:

[0005] The clamping diode, the clamping resistor, and the clamping capacitor constitute a clamping circuit;

[0006] The first end of the first IGCT device, the second end of the first diode, the first end of the first capacitor, the first end of the clamping diode, and the first end of the anode reactor are connected;

[0007] The second end of the first IGCT device, the first end of the second diode, the first end of the first resistor, the first end of the second IGCT device, the second end of the third diode, and the first end of the second capacitor are connected;

[0008] The first end of the first diode and the second end of the second diode are connected, and the second end of the first capacitor and the second end of the first resistor are connected;

[0009] The second end of the second IGCT, the first end of the fourth diode, the first end of the second resistor, the first end of the clamping capacitor, and the first end of the DC support capacitor are connected;

[0010] The second end of the clamping diode, the second end of the clamping capacitor, and the first end of the clamping resistor are connected;

[0011] The second end of the anode reactor, the second end of the clamping resistor, and the second end of the DC support capacitor are connected.

[0012] Based on the above solution, the present invention provides a low-stress and high-margin IGCT-MMC flexible DC transmission power module, which adopts the design of a series resistor-capacitor absorption circuit and series diodes. Through the series resistor-capacitor absorption circuit, the turn-off overshoot voltage of the IGCT device and the peak recovery power of the antiparallel diode can be reduced. When the first IGCT device or the second IGCT device turns off, the resistor-capacitor absorption circuit can share part of the current in the commutation valve circuit, thereby reducing the overvoltage generated by the rate of change of current on the stray inductance in the commutation circuit; through the series diodes, when the antiparallel diode reverses and recovers, the series diode design evenly divides the reverse recovery voltage, thereby reducing the reverse recovery peak power. The present invention further broadens the safe operating area of the power module, effectively reduces the switching stress of the power module, improves the operating margin, and enhances the operating reliability. Description of the Drawings

[0013] Figure 1 is the circuit structure diagram of a low-stress and high-margin IGCT-MMC flexible DC transmission power module of the present invention;

[0014] Figure 2 is the internal structure schematic diagram of the power module of the present invention;

[0015] Figure 3 is the assembly schematic diagram of the silicon stack crimping part of the present invention;

[0016] Figure 4 is the assembly schematic diagram of the disc spring part of the present invention.

[0017] Reference numerals: S1, the first IGCT device; S2, the second IGCT device; D1, the first diode; D2, the second diode; D3, the third diode; D4, the fourth diode; R1, the first resistor; R2, the second resistor; C1, the first capacitor; C2, the second capacitor; D CL , the clamping diode; R CL , the clamping resistor; C CL , the clamping capacitor; C DC , the DC support capacitor; L i , the anode reactor; 1, the outer shell part of the box body; 2, the silicon stack crimping part; 3, the anode reactor part; 4, the water pipe part; 5, the DC support capacitor part; 7, the silicon stack bottom plate; 8, the silicon stack pull rod; 9, the silicon stack top plate; 10, the pull rod nut; 11, the disc spring unit; 12-1 to 9, the radiator; 13, the clamping resistor; 14, the clamping diode; 15S1, the first IGCT device; 15S2, the second IGCT device; 16D1, the first diode; 16D2, the second diode; 17R1, the first resistor; 17R2, the second resistor; 18C1, the first capacitor; 18C2, the second capacitor; 19, the disc spring shaft; 20, the brass nut; 21, the disc spring; 22, the retaining ring; 23, the baffle plate. Detailed implementation manners

[0018] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0019] It should be noted that for the convenience of description, only the parts related to the relevant invention are shown in the accompanying drawings. Without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0020] It should be understood that the "system", "device", "unit" and / or "module" used in the present application is a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, they can be replaced by other expressions.

[0021] As shown in this application and the claims, unless the context clearly indicates otherwise, words such as "a", "an", "one", and / or "the" are not specifically singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of the clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements. An element defined by the statement "comprising one..." does not exclude the existence of other identical elements in the process, method, article, or device that includes the element.

[0022] In the description of the embodiments of this application, "a plurality" means two or more than two. The following terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0023] In addition, flowcharts are used in this application to illustrate the operations performed by the systems according to the embodiments of this application. It should be understood that the previous or subsequent operations are not necessarily executed precisely in sequence. On the contrary, the steps can be processed in reverse order or simultaneously. At the same time, other operations can also be added to these processes, or one or several steps can be removed from these processes.

[0024] Refer to Figure 1 , which is a schematic circuit topology diagram of an optional example of the low-stress high-margin IGCT-MMC flexible DC transmission power module proposed by the present invention. The module proposed in this embodiment may include but is not limited to the following structures:

[0025] A first IGCT device, a first fast-recovery diode and a second diode anti-parallel to the first IGCT device, a first capacitor and a first resistor in parallel with the first IGCT device;

[0026] A second IGCT device, a third fast-recovery diode and a fourth diode anti-parallel to the second IGCT device, a second capacitor and a second resistor in parallel with the second IGCT device;

[0027] A clamping circuit, including a clamping diode, a clamping resistor, and a clamping capacitor. The negative terminal of the clamping diode, the first end of the clamping capacitor, and one end of the clamping resistor are connected;

[0028] An anode reactor, one end of which is connected to the first IGCT device and the other end is connected to the clamping resistor;

[0029] A DC support capacitor, one end of which is connected to the clamping resistor and the other end is connected to the second IGCT device.

[0030] In some feasible embodiments, refer toFigure 2 The structure of the low stress and high margin IGCT-MMC flexible DC transmission power module is a box-type structure, which specifically includes the outer shell part of the box and the internal silicon stack crimping part, the anode reactor part, the water pipe part 4, and the DC support capacitor part 5, wherein:

[0031] Reference Figure 3 The silicon stack crimping part includes a silicon stack bottom plate, a silicon stack tie rod, a silicon stack top plate, a tie rod nut, a butterfly spring unit, a heat sink (12-1-4), a clamping resistor, a clamping diode, a first IGCT device, a second IGCT device, a first diode, a second diode, a first resistor, a second resistor, a first capacitor, a second capacitor and an upper tube anti-parallel copper busbar. The silicon stack crimping part is connected to the anode reactor part as a whole through 8 M8 bolts.

[0032] The silicon stack tie rod and the tie rod nut are installed between the silicon stack bottom plate and the top plate, and can move axially along the installation position. The first IGCT device, the second IGCT device and the anti-parallel diodes (the first diode, the second diode, the third diode and the fourth diode) are connected in anti-parallel connection, wherein the first IGCT device and the first diode and the second diode are connected to the heat sink (12-3) and the heat sink (12-9) through the upper tube anti-parallel copper busbar, and the second IGCT device and the third diode and the fourth diode are connected to the heat sink (12-4) and the heat sink (12-7) through the lower tube anti-parallel copper busbar. The clamping resistor is pressed into the silicon stack through the heat sink (12-1) and the heat sink (12-2), and the clamping diode is pressed into the silicon stack through the heat sink (12-2) and the heat sink (12-2). The heat sinks (12-1 to 9) are all made of 6063-T6 alloy aluminum. The silicon stack crimping part uses a silicon stack top plate, a silicon stack tie rod, a tie rod nut and a bottom plate to complete the assembly of the overall silicon stack frame, and a disc spring shaft butterfly spring unit is used to provide the required pressing force inside the silicon stack.

[0033] Reference Figure 4 The butterfly spring unit is installed between the silicon stack top plate and the heat sink (12-1), and the clamping resistor, the clamping diode, the first IGCT device, the second IGCT device, the anti-parallel diodes (the first diode, the second diode, the third diode, the fourth diode) and the heat sink (12-1-9) are given a test pressure pre-tightening force through the butterfly spring shaft, and the required clamping force inside the silicon stack is maintained by adjusting the brass nut.

[0034] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A low-stress and high-margin IGCT-MMC flexible DC transmission power module, characterized in that, It includes a first IGCT device, a second IGCT device, a first diode, a second diode, a third diode, a fourth diode, a first capacitor, a second capacitor, a first resistor, a second resistor, an anode reactor, a DC support capacitor and a clamping circuit, where: The first end of the first IGCT device, the second end of the first diode, the first end of the first capacitor, the first end of the anode reactor and the first end of the clamping circuit are connected; The second end of the first IGCT device, the first end of the second diode, the first end of the first resistor, the first end of the second IGCT device, the second end of the third diode and the first end of the second capacitor are connected; The first end of the first diode is connected to the second end of the second diode, and the second end of the first resistor is connected to the second end of the first capacitor; The second end of the second IGCT device, the first end of the fourth diode, the first end of the second resistor, the first end of the DC support capacitor and the second end of the clamping circuit are connected; The first end of the third diode is connected to the second end of the fourth diode, and the second end of the second capacitor is connected to the second end of the second resistor; The second end of the anode reactor, the second end of the DC support capacitor and the third end of the clamping circuit are connected.

2. The low-stress high-margin IGCT-MMC flexible DC transmission power module according to claim 1, wherein The clamping circuit includes a clamping diode, a clamping resistor and a clamping capacitor, where: The first end of the clamping diode is connected to the first end of the anode reactor; The second end of the clamping diode, the first end of the clamping resistor and the first end of the clamping capacitor are connected; The second end of the clamping capacitor is connected to the first end of the DC support capacitor; The second end of the clamping resistor is connected to the second end of the anode reactor.

3. The low-stress and high-margin IGCT-MMC flexible DC transmission power module according to claim 1, characterized in that, This low-stress and high-margin IGCT-MMC flexible DC transmission power module has a box structure, which is divided into a housing part and an internal silicon stack crimping part, anode reactor part, water pipe part and DC support capacitor part.

4. The low-stress high-margin IGCT-MMC flexible DC transmission power module according to claim 3, wherein, The silicon stack crimping part includes a silicon stack bottom plate, a silicon stack pull rod, a silicon stack top plate, a pull rod nut, a disc spring unit, a radiator, the clamping resistor, the clamping diode, the first IGCT device, the second IGCT device, the first diode, the second diode, the first resistor, the second resistor, the first capacitor, the second capacitor and an upper tube anti-parallel copper bar, where: The silicon stack pull rod and the pull rod nut are installed between the silicon stack bottom plate and the silicon stack top plate; The first IGCT device, the first diode and the second diode are connected above the radiator through the upper tube anti-parallel copper bar; The second IGCT device, the third diode and the fourth diode are connected above the radiator through the lower tube anti-parallel copper bar; Both the clamping resistor and the clamping diode are crimped inside the silicon stack through the radiator.

5. The low-stress high-margin IGCT-MMC flexible DC transmission power module according to claim 4, wherein The disc spring unit is installed between the silicon stack top plate and the radiator, and the disc spring unit applies a pre-tightening force to the clamping resistor, the clamping diode, the first IGCT device, the second IGCT device, the first diode, the second diode, the third diode, the fourth diode and the radiator through a spring shaft.

6. The low-stress high-margin IGCT-MMC flexible DC transmission power module according to claim 5, characterized in that, The disc spring unit maintains the required pressing force inside the silicon stack by adjusting the brass nut.

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