Cascade multi-level converter sub-module

Abstract

The invention provides a cascaded multilevel converter sub-module. The cascaded multilevel converter sub-module comprises a supporting box, the sub-module circuit assembly is arranged in the supporting box; the air cooling radiator is arranged in the supporting box and is attached to the sub-module circuit assembly; the control board card assembly is connected to the supporting box in a drawable manner and is used for controlling the sub-module circuit assembly to work; the device is small in overall size, high in compactness degree and simple in structure; heat dissipation is achieved by ingeniously arranging the air cooling radiator, compared with water cooling equipment, additional cooling auxiliary equipment is not needed, and the occupied space and maintenance cost is saved. Meanwhile, the drawable control board card assembly facilitates the replacement of the control board, is more convenient to maintain, and is suitable for the converter of a medium-and-small-capacity DC distribution network system.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronic conversion, and in particular relates to a cascaded multi-level converter submodule. Background Art

[0002] With economic development and social progress, the power load has increased rapidly, and the power demand and power quality requirements have continued to grow. Traditional distribution networks and power supply methods are increasingly unable to meet the requirements. Compared with AC distribution networks, DC distribution networks have higher performance in transmission capacity, system controllability and power supply quality. They can effectively reduce line losses, isolate AC and DC faults, support flexible and convenient access to renewable energy, and play an important role in the new power system with new energy as the main body in the future.

[0003] The converter is the core equipment of the DC distribution network. At present, the research and development of DC distribution network converters is still in the exploratory stage, and the high-voltage DC transmission technology is relatively mature. The existing high-voltage converters widely use modular multi-level AC-DC converters, which have been put into practical use. The modular multi-level converter contains 6 symmetrical bridge arms, each of which is usually cascaded by dozens or even hundreds of half-bridge sub-modules or full-bridge sub-modules. The numerous sub-modules are supported by several valve towers, and the modules are highly integrated and inconvenient to maintain; the cooling system usually adopts water cooling, which requires additional equipment such as water cooling pipes and water pumps, which takes up additional space and cost, and is not suitable for small and medium-capacity DC distribution network systems. Summary of the invention

[0004] In order to overcome the problems of large space occupation and inconvenient maintenance in the above-mentioned prior art, the present invention proposes a cascaded multi-level converter submodule, the submodule comprising:

[0005] Support box;

[0006] A submodule circuit assembly is arranged in the support box;

[0007] An air-cooled radiator is disposed in the support box and is attached to the submodule circuit assembly;

[0008] The control board assembly can be connected to the support box in a drawable manner and is used to control the operation of the submodule circuit assembly.

[0009] Preferably, the sub-module circuit component includes a plurality of half-bridge IGBT components connected in parallel, a capacitor component, a voltage-equalizing resistor and a protection circuit connected in parallel on the half-bridge IGBT component, an AC input busbar component connected to the AC output end of the half-bridge IGBT component, and a DC output busbar component connected to the protection circuit.

[0010] Preferably, the support box includes a box body and a partition arranged in the box body, the sub-module circuit assembly is arranged on one side of the partition, the air-cooled radiator is arranged on the other side of the partition, and the box body is provided with an air inlet and an air outlet that cooperate with the air-cooled radiator.

[0011] Preferably, the capacitor assembly and the half-bridge IGBT assembly are sequentially arranged on the partition along the ventilation direction of the air-cooled heat sink, and a plurality of the half-bridge IGBT assemblies are arranged in a row perpendicular to the ventilation direction;

[0012] And / or the voltage grading resistor and the protection circuit are arranged adjacent to each other;

[0013] And / or the AC input busbar assembly and the DC output busbar assembly are arranged at one end of the partition away from the capacitor assembly;

[0014] And / or a laminated busbar is arranged on the partition, and the laminated busbar is located between the capacitor component and the half-bridge IGBT component and is used to connect the two.

[0015] Preferably, the half-bridge IGBT assembly includes a plurality of IGBT devices, and the plurality of IGBT devices are arranged in a V-shape on the partition.

[0016] Preferably, the control board assembly includes a base plate arranged on the box body, a board box slidably connected to the base plate, and a control board arranged in the board box.

[0017] Preferably, a slideway is provided on the base plate, and a sliding buckle is provided on the board box, and the sliding buckle is clamped on the slideway and slides along it.

[0018] Preferably, the air-cooled radiator includes a radiator body attached to the partition and a ventilation duct arranged on the air inlet of the box body.

[0019] Preferably, the air inlet area of ​​the ventilation duct gradually decreases along the air inlet direction to increase the air inlet speed.

[0020] Preferably, the submodule further includes:

[0021] A Hall voltage sensor, disposed on the partition, for measuring the voltage of the submodule circuit assembly;

[0022] A Hall current sensor, disposed on the partition, for measuring the current of the submodule circuit component;

[0023] The power supply component is arranged in the box body and is electrically connected to the control board component, the Hall voltage sensor and the Hall current sensor.

[0024] Compared with the closest prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a cascaded multi-level converter submodule, comprising a support box; a submodule circuit component, which is arranged in the support box; an air-cooled radiator, which is arranged in the support box and fits the submodule circuit component; a control board component, which can be connected to the support box in a drawable manner and is used to control the operation of the submodule circuit component; the submodule has a small overall volume, a high degree of compactness and a simple structure; heat dissipation is achieved by cleverly arranging the air-cooled radiator, and compared with water-cooled equipment, no additional cooling auxiliary equipment is required, saving space and maintenance costs; at the same time, the drawable control board component facilitates the replacement of the control board, and maintenance is more convenient, and is suitable for converters of small and medium-capacity DC distribution network systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A circuit topology diagram of a cascaded multi-level converter submodule provided by the present invention;

[0027] Figure 2 A front view of a cascaded multilevel converter submodule provided by the present invention;

[0028] Figure 3 A back view of a cascaded multilevel converter submodule provided by the present invention;

[0029] Figure 4 The present invention provides a cascade multi-level converter submodule internal view Figure 1 ;

[0030] Figure 5 The present invention provides a cascade multi-level converter submodule internal view Figure 2 ;

[0031] Figure 6 A schematic diagram of the positional relationship between a first fixing plate, a second fixing plate, a supporting plate, a Hall current sensor, and a bypass switch of a cascaded multi-level converter submodule provided by the present invention;

[0032] Figure 7 A schematic diagram of the structure of a control board component of a cascaded multi-level converter submodule provided by the present invention;

[0033] Figure 8 A schematic diagram of the bottom structure of a control board assembly of a cascaded multi-level converter submodule provided by the present invention;

[0034] Fig. 9 A schematic diagram of the structure of a power supply component of a cascaded multi-level converter submodule provided by the present invention;

[0035] Fig.10A schematic diagram of the structure of an air-cooled heat sink for a cascaded multi-level converter submodule provided by the present invention;

[0036] Fig.11 A schematic diagram of the connection of the main internal electrical components of a cascaded multi-level converter submodule provided by the present invention;

[0037] Among them, 1-lifting ring, 2-ventilation duct, 3-upper cover, 4-right cover, 5-front cover, 6-A phase AC input busbar, 7-B phase AC input busbar, 8-C phase AC input busbar, 9-positive DC output busbar, 10-negative DC output busbar, 11-lower cover, 12-rear cover, 13-left cover, 14-frame, 15-capacitor assembly, 16-laminated busbar, 17-control board assembly, 18-bypass switch, 19-power supply assembly, 20-Hall electrode Flow sensor, 21-adapter board, 22-Hall voltage sensor, 23-air-cooled radiator, 24-first fixed plate, 25-second fixed plate, 26-support plate, 27-half-bridge IGBT assembly, 28-voltage equalizing resistor, 29-board box, 30-control board, 31-base plate, 32-handle, 33-sliding buckle, 34-energy power supply, 35-energy power supply box, 36-clip, 37-radiator body, 38-partition, 39-slide, 40-protection circuit. DETAILED DESCRIPTION

[0038] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0039] Embodiment 1:

[0040] The present invention provides a cascaded multi-level converter submodule, such as Figures 1 to 11 As shown, the submodule includes:

[0041] Support box;

[0042] A submodule circuit assembly is arranged in the support box;

[0043] An air-cooled heat sink 23 is disposed in the support box and is attached to the submodule circuit assembly;

[0044] The control board assembly 17 can be connected to the support box in a drawable manner and is used to control the operation of the sub-module circuit assembly.

[0045] The submodule has a small overall size, high compactness and simple structure. Heat dissipation is achieved through the clever arrangement of air-cooled radiators. Compared with water-cooled equipment, it does not require additional cooling auxiliary equipment, saving space and maintenance costs. At the same time, the removable control board assembly facilitates the replacement of the control board and makes maintenance more convenient. It is suitable for converters in small and medium-capacity DC distribution systems.

[0046] like Figure 1 As shown, the sub-module circuit component includes a plurality of half-bridge IGBT components 27 connected in parallel, a capacitor component 15, a voltage-equalizing resistor 28 and a protection circuit 40 connected in parallel on the half-bridge IGBT component 27, and an AC input busbar component connected to the AC output end of the half-bridge IGBT component 27, and a DC output busbar component connected to the protection circuit 40.

[0047] The half-bridge IGBT assembly 27 and the voltage balancing resistor 28 are connected via a busbar and a primary cable. Figure 1 The circuit structure shown is connected;

[0048] like Figure 1 As shown, the AC input busbar assembly includes an A-phase AC input busbar 6, a B-phase AC input busbar 7, and a C-phase AC input busbar 8, corresponding to Figure 1 The A, B, and C input terminals in the DC output busbar assembly include a positive DC output busbar 9 and a negative DC output busbar 10, corresponding to Figure 1 The DC+ and DC- output terminals in the .

[0049] In this embodiment, the half-bridge IGBT assembly 27 includes six IGBT devices, four of which are connected in series, and the other two IGBT devices are connected in series with the aforementioned four IGBT devices according to Figure 1 Connect in parallel in the manner shown;

[0050] The capacitor assembly 15 includes a plurality of capacitors, the number of which is twice the number of the half-bridge IGBT assembly 27, and the plurality of capacitors are divided into three groups, each group of two capacitors is connected in series, and the two capacitors in series are connected in parallel at both ends of the aforementioned four IGBT devices connected in series;

[0051] The protection circuit 40 includes four IGBT devices connected in series and a bypass switch 18. The bypass switch 18 is connected in parallel between the collector of the second IGBT device and the emitter of the third IGBT device, and the bypass switch 18 is connected between the positive DC output busbar 9 and the negative DC output busbar 10. The two ends of the bypass switch 18 are DC+ and DC- output ends.

[0052] The A-phase AC input busbar 6, the B-phase AC input busbar 7, the C-phase AC input busbar 8, the half-bridge IGBT assembly 27, the grading resistor 28, the laminated busbar 16, the positive DC output busbar 9, the negative DC output busbar 10 and the bypass switch 18 constitute the primary electrical connection of the entire converter submodule.

[0053] The support box includes a box body and a partition plate 38 arranged inside the box body. The sub-module circuit assembly is arranged on one side of the partition plate 38, and the air-cooled radiator 23 is arranged on the other side of the partition plate 38. An air inlet and an air outlet that cooperate with the air-cooled radiator 23 are opened on the box body.

[0054] As Figure 2 and Figure 3 shown, in this embodiment, the box body includes a frame 14, and upper cover plate 3, right cover plate 4, front cover plate 5, lower cover plate 11, rear cover plate 12, and left cover plate 13 that respectively cover six faces of the frame 14; the air inlet is opened on the rear cover plate 12, and the air outlet is opened on the front cover plate 5; heat dissipation holes are opened on the left cover plate 13, and lifting rings 1 are arranged at the four corners of the upper cover plate 3, and the lifting rings 1 are used for hoisting the sub-module; a busbar square hole is arranged on the front cover plate 5 for leading out the interfaces of the A-phase AC input busbar 6, B-phase AC input busbar 7, C-phase AC input busbar 8, positive DC output busbar 9, and negative DC output busbar 10.

[0055] In this embodiment, the partition plate 38 serves as the installation base for the sub-module circuit assembly and the air-cooled radiator 23. The partition plate 38 is in a C shape and wraps around the air-cooled radiator 23 for three weeks to achieve stable installation. The partition plate 38, the right cover plate 4, the front cover plate 5, and the rear cover plate 12 form a ventilation path for the radiator. The ventilation duct 2 is fixed on the rear cover plate 12 for radiator ventilation; the half-bridge IGBT assembly 27 and the voltage-sharing resistor 28 are tightly attached to the radiator body 37 through bolts and the partition plate 38. As Figure 6 , Fig.10 and Fig.11 shown, the half-bridge IGBT assemblies of each of the A, B, and C phases are arranged in a "pin" shape on the surface of the radiator body, and the voltage-sharing resistors and the IGBT devices of the protection circuit are arranged adjacent to each other. This arrangement method can reduce the length of the connecting busbars between the IGBTs, reduce the loop stray inductance, and secondly, can reduce the size of the radiator in the length direction, taking into account the arrangement and fixation of other devices, and the heat dissipation surface of the radiator is maximally utilized. In addition, the half-bridge IGBT assembly and the voltage-sharing resistor are in a parallel state in the short side direction of the radiator, and the short side direction of the radiator is used as the air-cooling flow direction, which can not only greatly reduce the wind resistance, but also improve the IGBT heat dissipation effect.

[0056] As Figure 6 shown, first fixing plates 24 and second fixing plates 25 are further arranged at the upper and lower positions of the partition plate 38, and a support plate 26 is arranged in the middle. The adapter board card 21 is fixed on the first fixing plates 24 and the second fixing plates 25;

[0057] As Figure 4 and Figure 5As shown, the support plate 26 and the Hall current sensor 20 are fixed on the partition 38, the control board assembly 17 and the power supply assembly 19 are fixed between the first fixed plate 24 and the support plate 26, and the Hall voltage sensor 22 is fixed between the second fixed plate 25 and the support plate 26.

[0058] like Fig.10 As shown, the capacitor assembly 15 and the half-bridge IGBT assembly 27 are sequentially arranged on the partition 38 along the ventilation direction of the air-cooled heat sink 23, and a plurality of the half-bridge IGBT assemblies 27 are arranged in a row perpendicular to the ventilation direction;

[0059] and / or the voltage balancing resistor 28 and the protection circuit 40 are arranged adjacent to each other;

[0060] and / or the AC input busbar assembly and the DC output busbar assembly are arranged at one end of the partition 38 away from the capacitor assembly 15;

[0061] And / or a laminated busbar 16 is disposed on the partition 38 , and the laminated busbar 16 is located between the capacitor component 15 and the half-bridge IGBT component 27 and is used to connect the two.

[0062] The half-bridge IGBT assembly 27 includes a plurality of IGBT devices, and the plurality of IGBT devices are arranged in a V-shape on the partition 38 .

[0063] like Figure 7 and Figure 8 As shown, the control board assembly 17 includes a base plate 31 arranged on the box body, a board box 29 slidably connected to the base plate 31 , and a control board 30 arranged in the board box 29 .

[0064] In this embodiment, the base plate 31 is supported by the first fixed plate 24 and the support plate 26. The front cover plate 5 is provided with a square hole for the board box. A handle 32 is provided on the outer wall of the board box 29. The board box 29 can be pulled out by the handle 32, which facilitates the disassembly and replacement of the control board 30.

[0065] The base plate 31 is provided with a slideway 39 , and the board box 29 is provided with a sliding buckle 33 . The sliding buckle 33 is clamped on the slideway 39 and slides along the slideway 39 .

[0066] The air-cooled radiator 23 includes a radiator body 37 attached to the partition plate 38 and a ventilation duct 2 arranged on the air inlet of the box.

[0067] The air inlet area of ​​the ventilation duct 2 gradually decreases along the air inlet direction, so as to increase the air inlet velocity.

[0068] The submodule also includes:

[0069] A Hall voltage sensor 22, disposed on the partition 38, for measuring the voltage of the submodule circuit assembly;

[0070] A Hall current sensor 20, disposed on the partition 38, for measuring the current of the submodule circuit assembly;

[0071] The power supply assembly 19 is disposed in the box and is electrically connected to the control board assembly 17 , the Hall voltage sensor 22 and the Hall current sensor 20 through secondary cables.

[0072] like Fig. 9 As shown, the power supply assembly 19 includes an energy extraction power supply box 35, and an energy extraction power supply 34 and a wire clamp 36 disposed in the energy extraction power supply box 35. The wire clamp 36 is used to fix the connection wire harness.

[0073] The half-bridge IGBT component 27 is first connected to the adapter board 21 through a flat cable, and the adapter board 21 is then connected to the control board component 17 through a flat cable. The Hall current sensor 20 and the Hall voltage sensor 22 are connected to the control board component 17 through signal lines.

[0074] The control board assembly 17, the power supply assembly 19, the Hall current sensor 20, the Hall voltage sensor 22, and the adapter board 21 constitute the secondary control and measurement connection of the entire submodule.

[0075] The present invention provides a cascaded three-level converter submodule, which adopts an integrated box-type design, an overall vertical vertical arrangement, a small overall volume and a simple structure. The cooling system adopts an air-cooling method, and the IGBT components of each phase A, B, and C are arranged in a "pin" shape on the surface of the air-cooled radiator. The voltage-equalizing resistor and the IGBT components of the protection circuit are arranged adjacently. This arrangement can reduce the length of the busbar connecting the IGBTs and reduce the circuit noise. Secondly, the length direction of the radiator can be reduced, and the arrangement and fixation of other devices can be taken into account. The heat dissipation surface of the radiator is maximized. In addition, the IGBT components and the voltage-equalizing resistor are in a parallel state in the short side direction of the radiator. The short side direction of the radiator is used as the air-cooling flow direction, which can not only greatly reduce the wind resistance, but also improve the heat dissipation effect of the IGBT. Compared with water-cooling equipment, no additional cooling auxiliary equipment is required, saving space and maintenance costs. The control board card box is designed as a pull-out drawer, which is convenient for board replacement. The technical solution of the present invention effectively utilizes space and has significant advantages such as small submodule volume, high compactness, convenient maintenance, small footprint and low cost.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the application, but these changes, modifications or equivalent substitutions are all within the protection scope of the claims of the present invention.

Claims

1. A cascaded multilevel converter submodule, characterized in that: The submodules include: Support box; A submodule circuit assembly is arranged in the support box; An air-cooled heat sink (23) is disposed in the support box and is fitted to the submodule circuit assembly; A control board card assembly (17) is retractably connected to the support box and is used to control the operation of the submodule circuit assembly.

2. A cascaded multilevel converter submodule according to claim 1, characterized in that: The submodule circuit assembly comprises a plurality of half-bridge IGBT assemblies (27) connected in parallel, a capacitor assembly (15) connected in parallel to the half-bridge IGBT assembly (27), a voltage grading resistor (28) and a protection circuit (40), an AC input busbar assembly connected to the AC output end of the half-bridge IGBT assembly (27), and a DC output busbar assembly connected to the protection circuit (40).

3. A cascaded multilevel converter submodule according to claim 2, characterized in that: The support box comprises a box body and a partition (38) arranged in the box body, the submodule circuit assembly is arranged on one side of the partition (38), the air-cooled radiator (23) is arranged on the other side of the partition (38), and the box body is provided with an air inlet and an air outlet that cooperate with the air-cooled radiator (23).

4. A cascaded multilevel converter submodule according to claim 3, characterized in that: The capacitor assembly (15) and the half-bridge IGBT assembly (27) are arranged in sequence on the partition (38) along the ventilation direction of the air-cooled heat sink (23), and a plurality of the half-bridge IGBT assemblies (27) are arranged in a row perpendicular to the ventilation direction; and / or the voltage balancing resistor (28) and the protection circuit (40) are arranged adjacent to each other; and / or the AC input busbar assembly and the DC output busbar assembly are arranged at one end of the partition (38) away from the capacitor assembly (15); And / or a laminated busbar (16) is arranged on the partition (38), and the laminated busbar (16) is located between the capacitor component (15) and the half-bridge IGBT component (27) and is used to connect the two.

5. The cascaded multilevel converter submodule according to claim 3, characterized in that: The half-bridge IGBT assembly (27) comprises a plurality of IGBT devices, and the plurality of IGBT devices are arranged in a V-shape on the partition (38).

6. The cascaded multilevel converter submodule according to claim 3, characterized in that: The control board assembly (17) comprises a base plate (31) arranged on the box body, a board box (29) slidably connected to the base plate (31), and a control board (30) arranged in the board box (29).

7. The cascaded multilevel converter submodule according to claim 6, characterized in that: The base plate (31) is provided with a slideway (39), the board card box (29) is provided with a sliding buckle (33), and the sliding buckle (33) is clamped on the slideway (39) and slides along the slideway.

8. The cascaded multilevel converter submodule according to claim 3, characterized in that: The air-cooled radiator (23) comprises a radiator body (37) attached to the partition (38) and a ventilation duct (2) arranged on the air inlet of the box.

9. The cascaded multilevel converter submodule according to claim 8, characterized in that: The air inlet area of ​​the ventilation duct (2) gradually decreases along the air inlet direction, so as to increase the air inlet velocity.

10. The cascaded multilevel converter submodule according to claim 3, characterized in that: The submodule also includes: A Hall voltage sensor (22), arranged on the partition (38), for measuring the voltage of the submodule circuit component; A Hall current sensor (20), arranged on the partition (38) and used for measuring the current of the submodule circuit component; The power supply component (19) is arranged in the box and is electrically connected to the control board component (17), the Hall voltage sensor (22) and the Hall current sensor (20).

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