CN213072474U

CN213072474U - Power assembly and wind power converter

Info

Publication number: CN213072474U
Application number: CN202022376375.1U
Authority: CN
Inventors: 符松格; 袁小峰
Original assignee: Xinjiang Goldwind Science and Technology Co Ltd
Current assignee: Jinfeng Technology Co ltd
Priority date: 2020-10-22
Filing date: 2020-10-22
Publication date: 2021-04-27
Anticipated expiration: 2030-10-22

Abstract

The utility model provides a power component and wind power converter, this power component include direct current capacitance pond, direct current connection row and a plurality of bridge arm, wherein, direct current capacitance pond includes at least one direct current capacitance array, and each direct current capacitance array includes a plurality of direct current electric capacity arrange one row of electric capacity binding post between two adjacent rows of direct current electric capacity in the direct current capacitance array, direct current connection row includes first coupling part and second coupling part, first coupling part is used for connecting one row of electric capacity binding post, the second coupling part is used for connecting a plurality of bridge arms. The utility model discloses among the above-mentioned power component and the wind power converter of exemplary embodiment, through the split type structural style of the capacitance pool that adopts low stray inductance to make each bridge arm have good effect of flow equalizing.

Description

Power assembly and wind power converter

Technical Field

The utility model relates to a direct current transmission technical field, more specifically say, relate to a power component and a wind power converter that has this power component.

Background

Currently, npc (Neutral Point clamp) type or anpc (active Neutral Point clamp) type three-level topologies can utilize an IGBT device with low blocking voltage to realize the improvement of the dc bus voltage, so as to improve the ac output voltage and enlarge the system power level, and thus, the three-level topologies are widely applied to wind power converters.

When the output current capability of a single NPC or ANPC bridge arm cannot meet the requirement of the wind power converter, the output current is generally improved by the direct hard parallel connection of the NPC or ANPC bridge arm in the conventional scheme.

Due to the multi-parallel structure of the NPC or ANPC bridge arm, the number of power assembly units, direct current capacitors and the area of a water cooling plate are increased, so that the weight of a power assembly is improved, and the convenience of installation and maintenance is reduced.

In addition, in order to ensure the parallel current sharing effect of the plurality of NPC or ANPC bridge arms, for example, in the current conversion process, it needs to be ensured that the stray inductances from the DC + of the DC capacitor to the positive pole loop of the IGBT are symmetrically consistent, and the NPs of the DC capacitor flow into the negative pole of the IGBT symmetrically consistent. However, due to the structure of the separation of the dc capacitor and the IGBT module, the dc capacitor and the IGBT module need to be lapped with the dc link bar, and at this time, the current path may be affected by the lapping point and become asymmetric. Meanwhile, for a parallel circuit of a plurality of NPC or ANPC bridge arms, after a structure that a double-phase module is matched with a split-type capacitance pool is adopted, extra stray inductance can be generated at the connecting position of the parallel circuit, so that the voltage stress is prominent, and the switching loss is increased.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a power component and wind power converter can obtain the circuit return path and the low stray inductance of symmetry to, based on the matching nature design of direct current run-on and direct current capacitor bank, can make each parallelly connected bridge arm have good effect of flow equalizing.

An aspect of the exemplary embodiments of the present invention provides a power assembly, the power assembly includes a dc capacitor pool, a dc link bank and a plurality of bridge arms, wherein, the dc capacitor pool includes at least one dc capacitor array, and each dc capacitor array includes a plurality of dc capacitors arrange one row of capacitance connecting terminal between two adjacent rows of dc capacitors in the dc capacitor array, the dc link bank includes first connecting portion and second connecting portion, first connecting portion is used for connecting one row of capacitance connecting terminal, the second connecting portion is used for connecting a plurality of bridge arms.

Optionally, the first connection portion of the dc link may include a plurality of capacitor connection terminals, the plurality of capacitor connection terminals are linearly arranged, each capacitor connection terminal of the plurality of capacitor connection terminals is connected to a corresponding capacitor connection terminal of the one row of capacitor connection terminals, the second connection portion of the dc link includes a plurality of bridge arm connection terminals, and the plurality of bridge arm connection terminals are linearly arranged.

Alternatively, the plurality of capacitor connection terminals may be divided into a plurality of first terminal groups, the plurality of bridge arm connection terminals may be divided into a plurality of second terminal groups, and/or the plurality of first terminal groups and the plurality of second terminal groups may be arranged in a one-to-one correspondence so that the lengths of commutation paths from the dc capacitor battery to the plurality of bridge arms and from the plurality of bridge arms to the dc capacitor battery are the same.

Alternatively, each first terminal group may include a first capacitor direct-current positive terminal, a first capacitor neutral point terminal, and a first capacitor direct-current negative terminal, which are sequentially arranged, and each second terminal group may include a first bridge arm direct-current positive terminal, a first bridge arm neutral point terminal, and a first bridge arm direct-current negative terminal, which are sequentially arranged.

Optionally, the dc capacitor array may include a first dc capacitor bank and a second dc capacitor bank alternately arranged, wherein the first dc capacitor bank may include a plurality of dc capacitors, each two dc capacitors are divided into a first capacitor bank to form a plurality of first capacitor banks, each first capacitor bank may include a second capacitor dc negative terminal, a second capacitor neutral terminal, a third capacitor neutral terminal, and a second capacitor dc positive terminal arranged in sequence, the second dc capacitor bank may include a plurality of dc capacitors, each two dc capacitors may be divided into a second capacitor bank to form a plurality of second capacitor banks, and each second capacitor bank may include a second capacitor neutral terminal, a second capacitor dc positive terminal, a second capacitor dc negative terminal, and a third capacitor dc neutral terminal arranged in sequence.

Optionally, the capacitor connection terminals on two sides of any one row of dc capacitors in each row of dc capacitors of the dc capacitor array are symmetrically disposed, and two capacitor connection terminals corresponding to two positions in the capacitor connection terminals on two sides of any one row of dc capacitors have opposite polarities.

Optionally, the first bridge arm neutral point terminal may include a first neutral point terminal and a second neutral point terminal, each bridge arm includes an upper bridge arm, a lower bridge arm, and an ac arm, wherein a second bridge arm dc positive terminal and a third neutral point terminal are led out from the upper bridge arm, the first bridge arm dc positive terminal and the first neutral point terminal are respectively connected to the dc connection row, the second bridge arm dc negative terminal and the fourth neutral point terminal are led out from the lower bridge arm, the first bridge arm dc negative terminal and the second neutral point terminal are respectively connected to the dc connection row, and the ac output terminal is led out from the ac arm.

Alternatively, the upper bridge arm may include a first switching tube and a second switching tube, a second bridge arm direct-current positive terminal is led out from a first end of the first switching tube, a second end of the first switching tube is connected to a first end of the second switching tube, a third neutral point sub-terminal is led out from a second end of the second switching tube, wherein the lower bridge arm may include a third switching tube and a fourth switching tube, a first end of the third switching tube is connected to a second end of the second switching tube, a fourth neutral point sub-terminal is led out from a first end of the third switching tube, a second end of the third switching tube is connected to a first end of the fourth switching tube, and a first bridge arm direct-current negative terminal is led out from a second end of the fourth switching tube, wherein the alternating-current arm may include a fifth switching tube and a sixth switching tube, a first end of the fifth switching tube is connected to a second end of the first switching tube, and a second end of the fifth switching tube is connected to a first end of the sixth switching tube, and the second end of the sixth switching tube is connected to the first end of the fourth switching tube, and an alternating current output terminal is led out from the first end of the sixth switching tube.

Optionally, the plurality of bridge arms are arranged on two sides of the heat sink, which face away from each other, wherein the bridge arms arranged on the same side of the heat sink share one dc connection row, the first connection portion of the one dc connection row is connected to one row of capacitance connection terminals arranged between any two adjacent rows of dc capacitances in the dc capacitance array, and/or each bridge arm is an NPC type bridge arm or an ANPC type bridge arm.

In another aspect of the exemplary embodiments of the present invention, a wind power converter is provided, which includes the above power module.

The utility model discloses among the above-mentioned power component and the wind power converter of exemplary embodiment, through the split type structural style of the capacitance pool that adopts low stray inductance to make each bridge arm have good effect of flow equalizing.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:

fig. 1 shows a schematic layout of a dc capacitive cell according to an exemplary embodiment of the present invention;

fig. 2 shows a front view of a dc link bank according to an exemplary embodiment of the present invention;

fig. 3 shows a side view of a dc link bank according to an exemplary embodiment of the present invention;

fig. 4 shows a top view of a dc link bank according to an exemplary embodiment of the present invention;

fig. 5 shows an electrically simplified schematic diagram of a dc link bank according to an exemplary embodiment of the present invention;

fig. 6 shows a schematic diagram of an NPC circuit topology according to an exemplary embodiment of the present invention;

fig. 7 shows an ANPC circuit topology according to an exemplary embodiment of the present invention;

FIG. 8 shows an ANPC bridge arm splice schematic according to an exemplary embodiment of the present invention;

fig. 9 shows an ANPC bridge arm structure schematic according to an exemplary embodiment of the present invention;

fig. 10 shows an ANPC bridge arm four parallel electrical schematic according to an exemplary embodiment of the present invention;

fig. 11 shows an ANPC bridge arm commutation loop schematic according to an exemplary embodiment of the present invention;

fig. 12 shows a schematic diagram of a three-level dc capacitor bank according to an exemplary embodiment of the present invention;

fig. 13 shows a schematic diagram of a symmetrical structure of a dc circuit according to an exemplary embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention provides a power assembly, which has a split structure of a capacitor pool with low stray inductance and a symmetrical circuit path based on matching design of a dc link and a dc capacitor pool, so that each parallel bridge arm has a good current equalizing effect.

In a preferred embodiment, the power assembly in exemplary embodiments of the present invention may include, but is not limited to, a parallel configuration of NPC-type bridge arms or ANPC-type bridge arms. According to the utility model discloses power component of exemplary embodiment includes: dc capacitor cell 100, dc link bank 200, and a plurality of bridge arms.

The arrangement of the dc capacitor cells 100 and the dc link bank 200 will now be described with reference to fig. 1.

Fig. 1 shows a schematic layout of a dc capacitive cell according to an exemplary embodiment of the present invention.

As shown in fig. 1, the dc capacitor battery 100 includes at least one dc capacitor array, each dc capacitor array includes a plurality of dc capacitors 10, and a row of capacitor terminals is disposed between two adjacent rows of dc capacitors in the dc capacitor array.

Here, the two adjacent rows of dc capacitors may include two adjacent rows of dc capacitors or two adjacent columns of dc capacitors in the dc capacitor array.

In the example shown in fig. 1, a row of capacitor connecting terminals is disposed between two adjacent rows of dc capacitors in the dc capacitor array as an example, but it should be understood that the present invention is not limited to this, and a row of capacitor connecting terminals may be disposed between two adjacent rows of dc capacitors in the dc capacitor array.

In a preferred example, the capacitor terminals disposed on both sides of any one row of dc capacitors in each row of dc capacitors of the dc capacitor array are symmetrically disposed, that is, two capacitor terminals disposed on both sides of any one row of dc capacitors are opposite in polarity.

The specific structure of the dc link bank 200 will be described with reference to fig. 2 to 5.

Fig. 2 shows a front view of a dc link bank according to an exemplary embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a dc link bank 200, where the dc link bank 200 includes a first connection portion 1 and a second connection portion 2, and the dc link bank 200 functions to connect a plurality of bridge arms and the dc capacitor cells 100.

Fig. 3 shows a side view of a dc link bank according to an exemplary embodiment of the present invention.

The first connecting part 1 of the dc connecting bank 200 is used to connect a row of capacitor terminals arranged between two adjacent rows of dc capacitors in the dc capacitor array, and the second connecting part 2 of the dc connecting bank 200 is used to connect a plurality of bridge arms.

As shown in fig. 3, the bottom terminal of the dc link bank 200 is a connection terminal for connection to each arm, and the top terminal of the dc link bank 200 is a connection terminal for connection to the dc capacitor cell 100.

As an example, the first connection portion 1 of the dc link bank 200 may include a plurality of capacitor connection terminals arranged in a straight line. For example, the plurality of capacitor connection terminals may be divided into a plurality of first terminal groups 11, in which case the plurality of first terminal groups 11 are arranged in a straight line.

The second connection part 2 of the dc link bank 200 may include a plurality of bridge arm connection terminals arranged in a straight line. For example, the plurality of bridge arm connection terminals may be divided into a plurality of second terminal groups 22, in which case the plurality of second terminal groups 22 are arranged in a straight line.

In one example, the plurality of first terminal sets 11 and the plurality of second terminal sets 22 are arranged in a one-to-one correspondence, the plurality of capacitor connection terminals and the plurality of bridge arm connection terminals are arranged in parallel, and each first terminal set 11 of the plurality of first terminal sets 11 is arranged in correspondence with a corresponding one of the plurality of second terminal sets 22 (as shown in fig. 4), so that the lengths of the commutation paths from the dc capacitor battery 100 to the plurality of bridge arms and from the plurality of bridge arms to the dc capacitor battery are the same.

In the exemplary embodiment of the present invention, each first terminal set 11 may include a first capacitor direct current positive terminal (DC +), a first capacitor neutral point terminal (NP), and a first capacitor direct current negative terminal (DC-), which are sequentially arranged, and each second terminal set 22 may include a first bridge arm direct current positive terminal (DC +), a first bridge arm neutral point terminal (NP), and a first bridge arm direct current negative terminal (DC-), which are sequentially arranged. As an example, the first leg neutral terminal (NP) may include a first neutral sub-terminal (NP1) and a second neutral sub-terminal (NP 2).

Fig. 4 shows a top view of a dc link bank according to an exemplary embodiment of the present invention.

As shown in fig. 4, each first terminal group 11 of the first connection portion 1 of the dc link bank 200 includes +, NP, and-arranged in sequence (in sequence from left to right), and each terminal of each first terminal group 11 is correspondingly connected to 3 capacitance terminals of a row of capacitance terminals on the dc capacitance battery 100. That is, the arrangement order of the capacitor connection terminals in each row of the capacitor connection terminals on the dc capacitor cell 100 coincides with the arrangement order of the capacitor connection terminals of the first connection portion 1 of the dc connection bank 200.

Each second terminal group 22 of the second connection part 2 of the dc link bank 200 includes, arranged in sequence (in sequence from left to right), NP1, NP2, and-each terminal of each second terminal group 22 is connected to a connection terminal on one bridge arm correspondingly.

Fig. 5 shows an electrically simplified schematic diagram of a dc link bank according to an exemplary embodiment of the present invention.

As shown in fig. 5, the current paths between the plurality of capacitance connection terminals and the plurality of arm connection terminals are shown by dotted lines. In this example, taking the parallel structure of 4 ANPC type bridge arms as an example, during the operation of the 4 ANPC type bridge arms, current flows from DC + of the DC capacitor cell to DC + of the bridge arms (as shown by a dotted line a in the figure), and at this time, the current paths of the 4 ANPC type bridge arms are equal in length. The current then commutates from NP of the dc capacitor cell to NP1 of the arm (as shown by the dashed line b), at which time the current paths of the 4-way ANPC arm are equally long. In the commutation process, the current flowing from the DC + of the direct current capacitor battery to the DC + of the bridge arm is gradually reduced, the current flowing from the NP of the direct current capacitor battery to the NP1 of the bridge arm is gradually increased, the change trends are opposite due to the same current direction, the back electromotive forces generated by stray inductances on two different current paths are equal in magnitude and opposite in direction according to the Lenz law, and therefore extra voltage stress generated in the commutation process is offset.

When current flows from NP2 of the arm to NP of the DC capacitor pool (as shown by the dashed line c), the current paths of the 4-way ANPC arm are equal in length, and the current flows to DC flowing from DC of the arm to the DC capacitor pool (as shown by the dashed line d), and the current paths of the 4-way ANPC arm are equal in length. In the commutation process, the current flowing from the NP2 of the bridge arm to the NP of the direct current capacitor pool is gradually reduced, the current flowing from the DC-of the bridge arm to the DC-of the direct current capacitor pool is gradually increased, the change trends are opposite due to the same current direction, the back electromotive forces generated by stray inductances on two different current paths are equal in magnitude and opposite in direction according to the Lenz's law, and therefore extra voltage stress generated in the commutation process is offset.

In the working process of the ANPC, the shortest current paths among the 4 parallel ANPC bridge arms can be always ensured to be equal in length, so that the static current equalizing effect on the direct-current connecting row is ensured. In the current conversion process, the current path difference between the ANPC type bridge arm current conversion paths is very small, so that the dynamic current equalizing effect on the direct current connecting bar is ensured.

In a preferred example, the dc capacitor array may include a first dc capacitor bank a and a second dc capacitor bank B alternately arranged, the first dc capacitor bank a may include a plurality of dc capacitors, each two dc capacitors are divided into a first capacitor group 33 to form a plurality of first capacitor groups 33, and the second dc capacitor bank B may include a plurality of dc capacitors, each two dc capacitors are divided into a second capacitor group 44 to form a plurality of second capacitor groups 44.

As an example, each first capacitance group 33 may include a second capacitance dc negative terminal (-), a second capacitance neutral point terminal (NP), a third capacitance neutral point terminal (NP), and a second capacitance dc positive terminal (+) arranged in sequence. Each second capacitor bank 44 may include a second capacitor neutral point terminal (NP), a second capacitor dc positive terminal (+), a second capacitor dc negative terminal (-), and a third capacitor neutral point terminal (NP) sequentially arranged.

An example of the arrangement of the dc capacitor cells 100 and the dc link bank 200 will be described with reference to the example shown in fig. 1. It should be understood that the number of dc capacitors 10 included in the dc capacitor battery 100 listed in fig. 1 is only an example, and can be adjusted by those skilled in the art according to actual needs.

As shown in the electrical schematic diagram of the dc capacitor cell 100 shown in fig. 1, in this example, the dc capacitor cell 100 employs a dc capacitor array with 6 rows and 7 columns, the connection position of the dc link 200 and the dc capacitor cell 100 is located between two columns of dc capacitors in the vertical direction, two dc capacitors in the first column from left to right (the first dc capacitor row) form a dc bus support topology, and are arranged in the order of-, NP, and + to form the first capacitor group 33. The dc capacitors in the second row (second dc capacitor row) from left to right form a dc bus supporting topology in pairs, and are arranged in order of NP, +, -, NP to form a second capacitor group 44. The first dc capacitor bank a and the second dc capacitor bank B are alternately arranged from left to right, that is, the dc capacitors in the third column, the fifth column and the seventh column from left to right have the same arrangement and combination manner as the first column, and the dc capacitors in the fourth column and the sixth column from left to right have the same arrangement and combination manner as the second column.

By adopting the arrangement and combination mode of the direct current capacitors, the current paths of the upper and lower groups of direct current capacitors can be overlapped with each other, and the voltage stress in the current conversion process is counteracted. At present, different output phases of the power module can be formed, when the upper half bus is discharged, the lower half bus is charged, namely a discharging current path from + to NP and a charging current path from NP to minus can be formed, and because the direct current capacitor always follows the combination form of minus NP, + or NP, +, -and NP in the arrangement and combination mode, the charging current path and the discharging current path can form a loop which is mutually overlapped on the whole direct current capacitor battery, thereby reducing the commutation stray inductance.

In the above example where the adjacent dc connection rows are symmetrically arranged, two capacitor connection terminals corresponding to the two adjacent rows of capacitor connection terminals have opposite polarities. As shown in fig. 1, the capacitance terminals corresponding to the positions may refer to two circled terminal sets in the figure, the terminal sequence in one of the two terminal sets may be DC +, NP, DC-, and the terminal sequence in the other of the two terminal sets may be DC-, NP, DC +. The symmetrical design of the split type connection structure of the ANPC four parallel connection capacitor pools is realized, the parallel flow equalizing effect is guaranteed, and the voltage stress is reduced based on the low stray inductance design of the split type connection structure of the four parallel connection capacitor pools.

In one example, the IGBT power modules are configured on both sides of the heat sink, and a single power module (as shown in fig. 7) forms a two-phase output topology. Because the two surfaces of the radiator are arranged in a left-right mirror image manner, the two adjacent rows of capacitance connecting terminals also present bilaterally symmetrical terminals, and the terminals of the two adjacent rows of capacitance connecting terminals are rotated by 180 degrees in a mirror image manner, as shown in fig. 1, the terminals of one row of capacitance connecting terminals are sequentially at terminal connection positions of 4 groups of ANPC type bridge arms including DC-, NP and DC +, and the terminals of the other row of capacitance connecting terminals are sequentially at terminal connection positions of 4 groups of ANPC type bridge arms including DC +, NP and DC-from top to bottom.

In the DC + to NP commutation process as described above, the commutation path between the single-phase power module and the DC capacitor pool is as indicated by the dashed line in fig. 1, and it can be seen that there are 3 groups of the nearest DC + to NP capacitors corresponding to the commutation process. Similarly, in the NP-to-DC commutation process described above, the commutation path between the single-phase power module and the DC capacitor pool is shown by the dotted line in fig. 1, and it can be seen that there are 3 sets of the nearest NP-to-DC capacitors corresponding to the commutation process.

It can be analyzed from fig. 1 that, at a group of capacitor terminals in a row of capacitor terminals, there are 3 groups of the closest dc capacitors for commutation as shown in the above figure. Therefore, the commutation paths of the direct current capacitor batteries between the parallel connection of the ANPC type bridge arms can be basically consistent. It should be understood that there are 3 sets of the most recent dc capacitors listed for commutation in the above example, but the present invention is not limited thereto, and the number of dc capacitors participating in commutation may be adjusted as needed.

The utility model discloses in the exemplary embodiment, because direct current run-on and direct current capacitor cell all adopt circuit design to offset the stray inductance that commutates to keep the symmetry in the route of commuting unanimous, consequently can realize the good effect of flow equalizing between a plurality of ANPC type bridge arms.

In exemplary embodiments of the present invention, each bridge arm may include, but is not limited to, an npc (Neutral Point clamp) type bridge arm or an anpc (active Neutral Point clamp) type bridge arm.

Fig. 6 shows a schematic diagram of an NPC circuit topology according to an exemplary embodiment of the present invention.

Fig. 6 shows a NPC three-level circuit topology, referred to as neutral point clamped three-level, typically midpoint clamped by diodes.

In the present example, the DC side uses two sets of DC capacitors C1 and C2 in series to form three potentials, DC + (for connection to the positive pole of the DC bus), NP (neutral point), and DC- (for connection to the negative pole of the DC bus). The four IGBT modules of T1, T2, T3 and T4 (including switching tubes and corresponding freewheeling diodes) are connected in series between DC + and DC-, and the AC (alternating current voltage) output terminal is located in the middle of the IGBT modules of T2 and T3. The NP potential is connected between T1 and T2 through a D5 freewheeling diode (point a in the upper panel), and the NP potential is connected between T3 and T4 through a D6 freewheeling diode (point B in the upper panel). Since D5 clamps the potential at Point a to NP when T2 is turned on and D6 clamps the potential at Point B to NP when T3 is turned on, the NPC topology is also referred to as a diode-clamped topology and may be represented by dnpc (diode Neutral Point clamp).

In the exemplary embodiment of the present invention, the connection manner between the plurality of bridge arms and the dc link is described with reference to fig. 7 to 9 by taking each bridge arm as an ANPC type bridge arm as an example.

Fig. 7 shows an ANPC circuit topology according to an exemplary embodiment of the present invention.

Fig. 7 shows an ANPC three-level circuit topology, referred to as neutral point clamped three-level, typically midpoint clamped by IGBT.

In the example, two groups of direct current capacitors C1 and C2 are adopted on the direct current side to be connected in series to form three potentials of DC +, NP and DC-. The four IGBT modules (including switching tubes and corresponding free-wheeling diodes) of T1, T2, T3 and T4 are connected in series between DC + and DC-, and the AC output terminal is located in the middle of the IGBTs of T2 and T3. The NP potential is connected between T1 and T2 (point a in the upper panel) through a freewheeling diode at T5, D5, and the NP potential is connected between T3 and T4 (point B in the upper panel) through a freewheeling diode at T6, D6. When T2 and T5 are turned on, the potential at point a is clamped to NP, and when T3 and T6 are turned on, the potential at point B is clamped to NP, so this NPC topology is also referred to as an active clamp ANPC topology.

In an example, each leg can include an upper leg, a lower leg, and an ac leg.

For example, a second arm direct-current positive terminal and a third neutral point terminal are led out from the upper arm, and are respectively connected to a first arm direct-current positive terminal and a first neutral point terminal of the direct-current connection bank, a second arm direct-current negative terminal and a fourth neutral point terminal are led out from the lower arm, and are respectively connected to a first arm direct-current negative terminal and a second neutral point terminal of the direct-current connection bank, and alternating-current output terminals are led out from the alternating-current arms, and are used for outputting alternating-current voltage.

As an example, the upper arm i may include a first switch tube T1 and a second switch tube T2 (and corresponding freewheeling diodes D1 and D2), a second arm DC positive terminal DC + is led out from a first end of the first switch tube T1, a second end of the first switch tube T1 is connected to a first end of the second switch tube T2, and a third neutral point terminal NP1 is led out from a second end of the second switch tube T2. A first terminal of the freewheeling diode D1 is connected to the first terminal of the first switch transistor T1, a second terminal of the freewheeling diode D1 is connected to the second terminal of the first switch transistor T1, a control terminal of the first switch transistor T1 receives a control signal, a first terminal of the freewheeling diode D2 is connected to the first terminal of the second switch transistor T2, a second terminal of the freewheeling diode D2 is connected to the second terminal of the second switch transistor T2, and a control terminal of the second switch transistor T2 receives the control signal.

The lower bridge arm II can comprise a third switching tube T3 and a fourth switching tube T4 (and corresponding freewheeling diodes D3 and D4 respectively), a first end of the third switching tube T3 is connected to a second end of the second switching tube T2, a fourth neutral point sub-terminal NP2 is led out from the first end of the third switching tube T3, a second end of the third switching tube T3 is connected to a first end of a fourth switching tube T4, and a first bridge arm direct current negative terminal DC is led out from the second end of the fourth switching tube T4. A first terminal of the freewheeling diode D3 is connected to the first terminal of the third switching transistor T3, a second terminal of the freewheeling diode D3 is connected to the second terminal of the third switching transistor T3, the control terminal of the third switching transistor T3 receives a control signal, a first terminal of the freewheeling diode D4 is connected to the first terminal of the fourth switching transistor T4, a second terminal of the freewheeling diode D4 is connected to the second terminal of the fourth switching transistor T4, and the control terminal of the fourth switching transistor T4 receives the control signal.

The alternating current arm iii comprises a fifth switching tube T5 and a sixth switching tube T6 (and respective freewheeling diodes D5 and D6), wherein a first end of the fifth switching tube T5 is connected to a second end of the first switching tube T1, a second end of the fifth switching tube T5 is connected to a first end of the sixth switching tube T6, a second end of the sixth switching tube T6 is connected to a first end of the fourth switching tube T4, and an alternating current output terminal AC is led out from the first end of the sixth switching tube T6. A first terminal of the freewheeling diode D5 is connected to the first terminal of the fifth switching tube T5, a second terminal of the freewheeling diode D5 is connected to the second terminal of the fifth switching tube T5, a control terminal of the fifth switching tube T5 receives the control signal, a first terminal of the freewheeling diode D6 is connected to the first terminal of the sixth switching tube T6, a second terminal of the freewheeling diode D6 is connected to the second terminal of the sixth switching tube T6, and a control terminal of the sixth switching tube T6 receives the control signal.

By way of example, each of the switching tubes may include, but is not limited to, an IGBT (insulated gate bipolar transistor) power module assembly, that is, a functional unit composed of an IGBT module, a driving board, and a heat sink, and has a complete independent structural form.

Fig. 8 shows an ANPC bridge arm splice schematic according to an exemplary embodiment of the present invention.

At present, no complete DNPC and ANPC bridge arm packaged IGBT module exists, and the capacity of a high-power wind power generation converter is generally more than 2MW, so that a DNPC and ANPC topological structure applied to a three-level converter generally adopts a plurality of half-bridge IGBT modules or single-tube IGBT modules to be spliced to form DNPC and ANPC bridge arms, and a plurality of DNPC and ANPC bridge arms are directly and hard connected in parallel to form single-phase output of the converter, wherein the structure is shown in fig. 8.

FIG. 9 shows an ANPC bridge arm structure schematic diagram according to an exemplary embodiment of the present invention

As shown in fig. 9, a schematic diagram of splicing an ANPC three-level bridge arm is shown, where the three-level bridge arm is formed by three IGBT modules packaged by two double-tube econdual, and corresponds to an upper bridge arm I, a lower bridge arm II, and an ac arm III, respectively. The IGBT modules of the double-tube EconoDUAL of the upper bridge arm I of the structural part form switches T1, D1, T5 and D5 of an ANPC bridge arm, the IGBT modules of the double-tube EconoDUAL of the lower bridge arm II of the structural part form switches T2, D2, T3 and D3 of the ANPC bridge arm, and the IGBT modules of the double-tube EconoDUAL of the alternating current arm III of the structural part form switches T4, D4, T6 and D6 of the ANPC bridge arm.

According to the structural scheme formed by the electrical topology, the + stage of the double-tube IGBT module I is connected to DC +, the-pole of the double-tube IGBT module I is connected to NP, the AC output end (shown as point A in figure 7) of the double-tube IGBT module I is connected to the + pole of the double-tube IGBT module III, the + pole of the double-tube IGBT module III is connected to the AC output end of the double-tube IGBT module I, the-pole of the double-tube IGBT module III is connected to the AC output end (shown as point B in figure 7) of the double-tube IGBT module II, the AC output end of the double-tube IGBT module III is connected to AC total output of the ANPC topology, the + pole of the double-tube IGBT module II is connected to NP, the-pole of the double-tube IGBT module II is connected to DC-, and.

In one example, three double-tube IGBT modules may be in a delta-symmetrical structure, and thus their physical combination connection adopts a common delta-structure, with structure part I and structure part II connected side by side to a dc terminal, and structure part III connected to an ac terminal.

For example, in the example shown in fig. 9, 5 is the IGBT module of the structural part I, 4 is the IGBT module of the structural part II, and 2 is the IGBT module of the structural part III, and three IGBT modules are in a delta distribution structure. The IGBT module comprises a structure part I, a structure part II, a structure part III, an AC output end, a connecting copper bar and a connecting structure part 1, wherein the structure part III is an AC output end of the IGBT module, the connecting copper bar is 3, the AC output end of the IGBT module of the structure part II and the negative level of the structure part III are respectively connected, and the connecting copper bar is 10, the AC output end of the IGBT module of the structure part I and the. 9 is the positive level of the IGBT module of the structural part I, connected to the DC + busbar, 8 is the negative level of the IGBT module of the structural part I, connected to the NP busbar, 7 is the positive level of the IGBT module of the structural part II, connected to the NP busbar, and 6 is the negative level of the IGBT module of the structural part II, connected to the DC-busbar. The direct current connecting row is marked with marks of + and NP and is correspondingly connected to the terminal of the IGBT module, and the direct current connecting row corresponds to 4 ANPC bridge arms connected in parallel.

Fig. 10 shows an ANPC bridge arm four parallel electrical schematic according to an exemplary embodiment of the present invention.

Fig. 10 is an electrical schematic diagram of four parallel ANPC bridge arms, in which DC terminals DC +, NP, and DC-of the four ANPC bridge arms are respectively connected in parallel, and AC terminals AC of the four ANPC bridge arms are connected in parallel. Meanwhile, points a of the four ANPC bridge arms are also connected together in parallel, as shown by the dotted lines in the above figure, and points B of the four ANPC bridge arms are also connected together in parallel, as shown by the dotted and dashed lines in the above figure.

Fig. 11 shows an ANPC bridge arm commutation loop schematic according to an exemplary embodiment of the present invention.

Fig. 11 is a schematic diagram of a commutation loop of an ANPC three-level circuit, in the commutation process numbered (i), current flows in the direction of flowing out of an AC terminal, when a T1 switch tube and a T2 switch tube are simultaneously turned on, the current flows according to a dotted line path, when a T1 switch tube is turned off, the current flows according to a dot-dash line path, gate-level interlocks of the T1 switch tube and the T3 switch tube are turned on, a T2 switch tube is in a normally-on state, and the current is switched between the dotted line and the dot-dash line. The dotted line current flows from the NP potential and the output is at zero level, and the dotted line current flows from the DC + potential and the output is at positive level. And the commutation path numbered third is consistent with the commutation path numbered first in analysis method, and the output is respectively zero level and positive level, which is not described herein again.

In the commutation process of number (II), the current flows out of the AC terminal, when the T4 switch tube is turned on, the current flows through the dotted path, and at this time, the current flows out of D3 and D4. When the T4 switch is turned off, the T6 switch is turned on, the potential at point B is clamped to the potential at point NP, the current flows out from the T6 switch through the D3, and the current flows through the dotted-line path. The dash-dot line current flows out of the NP potential, outputs zero level, the dashed line current flows out of the DC-potential, and the output is negative level. The commutation path numbered r is identical to the commutation path numbered r in analysis method, and outputs are a zero level and a negative level, respectively, which is not described herein again.

The commutation process forms PWM output switching pulses of an ANPC three-level bridge arm, and the ANPC bridge arm can output three states of a positive level, a zero level and a negative level. The ANPC can always maintain the small loop commutation path switching from the outer tube (T1, T4 or D1, D4) to the inner tube (T2, T3 or D2, D3).

Fig. 12 shows a schematic diagram of a three-level dc capacitor bank according to an exemplary embodiment of the present invention.

The three-level direct-current capacitor adopts a structural form that two groups of capacitors are connected in series, an upper half bus and a lower half bus of the direct-current bus are respectively formed, and DC +, NP and DC-potentials are independently supported.

By adopting the structure form that the direct current capacitance pool and the IGBT power assembly are separated, all direct current capacitors of a three-phase bridge arm form the independent direct current capacitance pool, the IGBT module, the radiator and a single-phase bridge arm formed by driving form a single IGBT power assembly module, and the IGBT power assembly module and the direct current capacitance pool adopt the structure form that the direct current capacitance pool and the IGBT power assembly module can be physically separated, so that the disassembly and the maintenance are convenient, the reduction of the maintenance weight is realized, the reduction of the maintenance cost is considered, and in addition, the direct current capacitance pool and the IGBT power assembly module can be independently maintained.

It can be analytically derived from the commutation loop shown in fig. 11 that the direct current flows from the DC + stage of the DC capacitor cell to the positive pole of the IGBT of the structural part I and switches the current path to flow from the NP stage of the DC capacitor cell to the negative pole of the IGBT of the structural part I. In order to ensure the parallel current sharing effect of the plurality of ANPC bridge arms, in this process, it needs to be ensured that the stray inductances of the positive loops from the DC + of the DC capacitor pool to the IGBTs of the structural part I are symmetrically consistent, and the negative poles of the IGBTs from the NP level of the DC capacitor flowing into the structural part I are symmetrically consistent (other current conversion processes are similar), as shown in fig. 13, under the plurality of parallel current paths of the ANPC bridge arms.

The utility model discloses in the exemplary embodiment, through the structural style of the split type double-phase power component in capacitance pond that proposes to through the dc link bar of rational design, guaranteed the circuit loop route and the low stray inductance of symmetry, through the matching nature design of dc capacitance pond and link bar, guarantee from the complete unanimity of the current conversion route of capacitance pond to IGBT module simultaneously, guaranteed the good effect of flow equalizing of the four parallelly connected bridge arms of ANPC.

It should be understood that the above description has been presented by taking an ANPC four-parallel bridge arm as an example, but the present invention is not limited thereto, and is applicable to a parallel structure of a plurality of ANPC bridge arms, such as three-parallel or five-parallel.

According to an exemplary embodiment of the present invention, there is also provided a wind power converter, including at least one of the above-mentioned power components.

According to the utility model discloses power component and wind-powered electricity generation converter of exemplary embodiment has realized the effect of flow equalizing through the circuit design that DC capacitance pond adopted split type structure and symmetry.

While the present application has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present application as defined by the following claims.

Claims

1. A power module, characterized in that it comprises a DC capacitor bank, a DC link bank and a plurality of bridge arms,

wherein the DC capacitor pool comprises at least one DC capacitor array, each DC capacitor array comprises a plurality of DC capacitors, a row of capacitor connecting terminals are arranged between two adjacent rows of DC capacitors in the DC capacitor array,

the direct current connection row comprises a first connection part and a second connection part, the first connection part is used for connecting the row of the capacitor wiring terminals, and the second connection part is used for connecting the plurality of bridge arms.

2. The power module of claim 1, wherein the first connection portion of the DC connection bank includes a plurality of capacitor connection terminals arranged in a line, each capacitor connection terminal of the plurality of capacitor connection terminals connected to a corresponding one of the capacitor connection terminals of the bank,

the second connecting part of the direct current connecting row comprises a plurality of bridge arm connecting terminals which are linearly arranged.

3. The power assembly according to claim 2, wherein the plurality of capacitance connection terminals are divided into a plurality of first terminal groups, the plurality of bridge arm connection terminals are divided into a plurality of second terminal groups, and/or the plurality of first terminal groups are arranged in one-to-one correspondence with the plurality of second terminal groups so that the lengths of commutation paths from the dc capacitor battery to the plurality of bridge arms and from the plurality of bridge arms to the dc capacitor battery are the same.

4. The power assembly of claim 3, wherein each first terminal set comprises a first positive capacitive DC terminal, a first neutral capacitive terminal, and a first negative capacitive DC terminal arranged in sequence,

each second terminal group comprises a first bridge arm direct current positive terminal, a first bridge arm neutral point terminal and a first bridge arm direct current negative terminal which are sequentially arranged.

5. The power assembly of claim 4, wherein the DC capacitor array comprises first and second alternating DC capacitor banks,

wherein the first direct current capacitor bank comprises a plurality of direct current capacitors, every two direct current capacitors are divided into a first capacitor group to form a plurality of first capacitor groups, each first capacitor group comprises a second capacitor direct current negative terminal, a second capacitor neutral point terminal, a third capacitor neutral point terminal and a second capacitor direct current positive terminal which are sequentially arranged,

the second direct current capacitor bank comprises a plurality of direct current capacitors, every two direct current capacitors are divided into a second capacitor group to form a plurality of second capacitor groups, and each second capacitor group comprises a second capacitor neutral point terminal, a second capacitor direct current positive terminal, a second capacitor direct current negative terminal and a third capacitor neutral point terminal which are sequentially arranged.

6. The power assembly according to claim 5, wherein the capacitor terminals arranged on both sides of any one row of the DC capacitors in the DC capacitor array are symmetrically arranged, and two capacitor terminals arranged on both sides of the any one row of the DC capacitors are opposite in polarity.

7. The power assembly of claim 4, wherein the first leg neutral terminals comprise a first neutral terminal and a second neutral terminal, each leg comprising an upper leg, a lower leg, and an AC leg,

wherein a second bridge arm direct current positive terminal and a third neutral point terminal are led out from the upper bridge arm and are respectively connected to a first bridge arm direct current positive terminal and a first neutral point terminal of the direct current connection row,

a second bridge arm direct-current negative terminal and a fourth neutral point terminal are led out from the lower bridge arm and are respectively connected to the first bridge arm direct-current negative terminal and the second neutral point terminal of the direct-current connecting row,

an AC output terminal is led out from the AC arm.

8. The power assembly of claim 7, wherein the upper leg includes a first switch tube and a second switch tube,

a second bridge arm direct-current positive terminal is led out from the first end of the first switching tube, the second end of the first switching tube is connected to the first end of the second switching tube, a third neutral point terminal is led out from the second end of the second switching tube,

wherein the lower bridge arm comprises a third switching tube and a fourth switching tube,

the first end of the third switching tube is connected to the second end of the second switching tube, a fourth neutral point sub-terminal is led out from the first end of the third switching tube, the second end of the third switching tube is connected to the first end of the fourth switching tube, a first bridge arm direct current negative terminal is led out from the second end of the fourth switching tube,

wherein the alternating current arm comprises a fifth switching tube and a sixth switching tube,

the first end of the fifth switching tube is connected to the second end of the first switching tube, the second end of the fifth switching tube is connected to the first end of the sixth switching tube, the second end of the sixth switching tube is connected to the first end of the fourth switching tube, and an alternating current output terminal is led out from the first end of the sixth switching tube.

9. The power assembly of claim 1, wherein the plurality of bridge arms are arranged on two sides of the heat sink facing away from each other, wherein the bridge arms arranged on the same side of the heat sink share one DC connection row, the first connection portion of the one DC connection row connects one row of capacitance terminals arranged between any two adjacent rows of DC capacitances in the DC capacitance array,

and/or each bridge arm is an NPC type bridge arm or an ANPC type bridge arm.

10. Wind power converter, characterized in that it comprises a power module according to any one of claims 1-9.