Main circuit arrangement of a three-phase ac motor drive system controller

Abstract

The application discloses a main loop arrangement structure of a three-phase alternating current motor driving system controller, and the structure comprises a power module with positive and negative busbars and a supporting capacitor, wherein the positive and negative busbars of the power module and the positive and negative busbars of the supporting capacitor are connected by bolts and inserts to form an inverter main loop, the positive and negative busbars of the power module extend to the bolt and insert positions along a mounting plane, the positive and negative busbars of the supporting capacitor extend horizontally to the power module and are then vertically bent to the mounting plane, and then extend to the bolt and insert positions along the mounting plane, the positive and negative busbars of the power module and the positive and negative busbars of the supporting capacitor are arranged in the same direction at the bolt and insert positions, and the positive and negative busbars of the power module and the positive and negative busbars of the supporting capacitor are connected by the bolts and inserts at the bolt and insert positions. The structure reduces the surge voltage caused by the stray inductance, avoids the danger of the power module being broken down, ensures the switching characteristics of the power module, and improves the reliability of the motor driving control.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of motor control technology, in particular to a main loop arrangement structure of a three-phase AC motor drive system controller. BACKGROUND

[0002] In a three-phase AC motor drive system, high-frequency carrier wave is used to drive the power module at high speed, and the surge voltage proportional to the stray inductance of the drive main loop is loaded on the power module. The surge voltage V1 is calculated as formula (1):

[0003]

[0004] Among them,

[0005] Then

[0006] In the formula, L is the stray inductance, φ is the magnetic flux, I is the current, B is the magnetic induction intensity, a is the length of the main loop connection terminal busbar, w is the width of the main loop connection terminal busbar, h is the spacing of the laminated busbar, and μ0 is the vacuum permeability.

[0007] It can be seen that reducing the stray inductance to the greatest extent can reduce the surge voltage V1. When the surge voltage V1 is too large, it may cause the power module to be damaged by breakdown. Therefore, how to reduce the stray inductance of the drive main loop is an important research topic.

[0008] As shown in Figure 1 and Figure 2 , the main loop of the controller is usually composed of a power module and a support capacitor. The power module and the support capacitor are connected together by a busbar through a bolt. The positive busbar 11 and the negative busbar 12 of the power module 1 are connected together with the positive busbar 21 and the negative busbar 22 of the support capacitor 2 through the bolt 3 and the insert 4. However, in this structure, the stray inductance of the bolt area A is large because the bolt area A is the connection part of the bolt, and the positive and negative busbars cannot be used in a laminated manner. At the same time, the area B on both sides of the bolt area A is also large in stray inductance because the area B cannot be used in a laminated manner to reduce the inductance in consideration of the assembly space and the insulation distance of the positive and negative busbars. Figure 1 and Figure 2 As shown in and

[0009] In the main circuit, the stray inductance of the bolt area A and the areas B on both sides seriously affects the switching characteristics of the power module and reduces the reliability of the motor drive control. SUMMARY

[0010] The technical problem to be solved by the present application is to provide a main circuit arrangement structure of a three-phase alternating current motor drive system controller, which reduces the surge voltage caused by the stray inductance, avoids the risk of breakdown of the power module, ensures the switching characteristics of the power module, and improves the reliability of the motor drive control.

[0011] To solve the above technical problems, the main circuit arrangement structure of the three-phase alternating current motor drive system controller comprises a power module with positive and negative busbars and a support capacitor with positive and negative busbars, wherein the positive busbar of the power module and the positive busbar of the support capacitor and the negative busbar of the power module and the negative busbar of the support capacitor are connected by bolts and inserts to form an inverter main circuit, the positive and negative busbars of the power module extend to the bolt and insert positions along the installation plane, the positive and negative busbars of the support capacitor extend horizontally towards the power module and then vertically bend to the positive and negative busbar installation planes, and then extend to the bolt and insert positions along the installation plane, the positive and negative busbars of the power module and the positive and negative busbars of the support capacitor are arranged in the same direction in the bolt and insert positions, so that the current directions of the positive busbar of the power module and the positive busbar of the support capacitor are opposite at the connection, the current directions of the negative busbar of the power module and the negative busbar of the support capacitor are opposite at the connection, the area of the current loop is minimum at this time, and the positive and negative busbars of the power module and the positive and negative busbars of the support capacitor are connected by bolts and inserts at the bolt and insert positions.

[0012] Further, the positive and negative busbars of the support capacitor are bent to form at least parallel planes in the same direction as the positive and negative busbars of the power module.

[0013] Further, the positive and negative busbars of the support capacitor are bent to form a first horizontal plane, a vertical plane and a second horizontal plane, and the positive and negative busbars of the second horizontal plane are connected in the same direction and in parallel with the positive and negative busbars of the power module by bolts and inserts.

[0014] Further, the bolt and insert positions are adjacent to the first horizontal plane and the vertical plane, and the bolt and insert and the first horizontal plane and the vertical plane of the connected busbar form opposite current directions, and the area of the current loop is minimum at this time.

[0015] Further, the current loop area at the connection of the positive busbar of the power module and the positive busbar of the support capacitor is minimum, and the current loop area at the connection of the negative busbar of the power module and the negative busbar of the support capacitor is minimum.

[0016] Because the main circuit layout structure of the three-phase AC motor drive system controller of this invention adopts the above-mentioned technical solution, namely, this structure includes a power module with positive and negative busbars and a support capacitor with positive and negative busbars, wherein the positive busbar of the power module and the positive busbar of the support capacitor, and the negative busbar of the power module and the negative busbar of the support capacitor are respectively connected by bolts and inserts to form the inverter main circuit. The positive and negative busbars of the power module extend along the mounting plane to the bolt and insert positions, and the positive and negative busbars of the support capacitor extend horizontally towards the power module and then bend vertically to the mounting plane, and then extend along the mounting plane to the bolt and insert positions. The positive and negative busbars of the power module and the positive and negative busbars of the support capacitor are arranged in the same direction at the bolt and insert positions, and are respectively connected by bolts and inserts at the bolt and insert positions. This structure reduces surge voltage caused by stray inductance, avoids the risk of power module breakdown, ensures the switching characteristics of the power module, and improves the reliability of motor drive control. Attached Figure Description

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments:

[0018] Figure 1 and Figure 2 A schematic diagram of the main circuit layout of a traditional controller;

[0019] Figure 3 This is a schematic diagram of the main circuit layout structure of the three-phase AC motor drive system controller of the present invention;

[0020] Figure 4 This diagram illustrates the arrangement of bolts and inserts on the positive and negative busbars of the supporting capacitor in this structure.

[0021] Figure 5 This is a schematic diagram of the extended and bent structure of the positive and negative busbars of the power module in this structure;

[0022] Figure 6 This diagram illustrates the arrangement of bolts and inserts on the positive and negative busbars of the power module in this structure.

[0023] Figure 7 This is a schematic diagram showing the positive and negative busbars arranged vertically for the power modules and supporting capacitors in this structure.

[0024] Figure 8 This is a schematic diagram of the positive and negative busbar connection terminals in this structure, which consist of bolts and inserts.

[0025] Figure 9 This diagram illustrates the connection of the positive and negative busbars in this structure using bolts and inserts. Detailed Implementation

[0026] Implementation, for example Figure 3As shown, the main loop arrangement structure of the three-phase AC motor drive system controller of the application comprises a power module 1 with positive and negative busbars and a support capacitor 2 with positive and negative busbars, wherein the positive busbar 11 of the power module 1 and the positive busbar 21 of the support capacitor 2 and the negative busbar 12 of the power module 1 and the negative busbar 22 of the support capacitor 2 are connected by bolts 3 and inserts 4 to form an inverter main loop, respectively, the positive and negative busbars 11 and 12 of the power module 1 extend along the mounting plane to the positions of the bolts 3 and inserts 4, the positive and negative busbars 21 and 22 of the support capacitor 2 extend horizontally towards the power module 1 and then vertically bend to the positive and negative busbar mounting planes, and then extend along the mounting plane to the positions of the bolts 3 and inserts 4, the positive and negative busbars 11 and 12 of the power module 1 and the positive and negative busbars 21 and 22 of the support capacitor 2 are arranged in the same direction in a stacked manner at the positions of the bolts 3 and inserts 4, so that the current directions of the positive busbar 11 of the power module 1 and the positive busbar 21 of the support capacitor 2 at the connection are opposite, and the current directions of the negative busbar 12 of the power module 1 and the negative busbar 22 of the support capacitor 2 at the connection are opposite, at this time, the area of the current loop is the smallest, and the positive and negative busbars 11 and 12 of the power module 1 and the positive and negative busbars 21 and 22 of the support capacitor 2 are connected by the bolts 3 and inserts 4 at the positions of the bolts 3 and inserts 4, respectively.

[0027] Preferably, the positive and negative busbars 21 and 22 of the support capacitor 2 are bent to form parallel planes in the same direction as the positive and negative busbars 11 and 12 of the power module 1.

[0028] Preferably, the positive and negative busbars 21 and 22 of the support capacitor 2 are bent to form a first horizontal plane 23, a vertical plane 24, and a second horizontal plane 25, and the positive and negative busbars 21 and 22 of the second horizontal plane 25 are connected in the same direction as the positive and negative busbars 11 and 12 of the power module 1 by the bolts 3 and inserts 4.

[0029] Preferably, the positions of the bolts 3 and inserts 4 are adjacent to the first horizontal plane 23 and the vertical plane 24, and the bolts 3 and inserts 4 form opposite current directions with the first horizontal plane 23 and the vertical plane 24 of the connected busbars, at this time, the area of the current loop is the smallest.

[0030] Preferably, the area of the current loop at the connection of the positive busbar 11 of the power module 1 and the positive busbar 21 of the support capacitor 2 is the smallest, and the area of the current loop at the connection of the negative busbar 12 of the power module 1 and the negative busbar 22 of the support capacitor 2 is the smallest.

[0031] In the above structure, the positive and negative busbars of the supporting capacitor are extended and bent to form a connection surface in the same direction as the positive and negative busbars of the power module. However, there are many variations depending on the position of the power module and the supporting capacitor in the controller. It is not limited to the extension and bending of the positive and negative busbars of the supporting capacitor. Similarly, the positive and negative busbars of the power module can also be extended and bent. Finally, the positive and negative busbars of the power module and the supporting capacitor are arranged in the same direction at the bolt and insert positions and then connected by bolts and inserts.

[0032] like Figure 4 As shown, when bolt 3 and insert 4 are set on the top surface of supporting capacitor 2, the positive and negative busbars 21 and 22 of supporting capacitor 2 extend towards power module 1 to form a first horizontal surface 23, then bend vertically to form a vertical surface 24, and then bend vertically again to form a second horizontal surface 25. The positive and negative busbars 11 and 12 of power module 1 extend horizontally to the position of bolt 3 and insert 4. At the position of bolt 3 and insert 4, the positive and negative busbars 11 and 12 of power module 1 are connected to the positive and negative busbars 21 and 22 of supporting capacitor 2 through bolt 3 and insert 4, so that the current direction of positive busbars 11 and 21 of power module 1 and supporting capacitor 2 is opposite, and the current direction of negative busbars 12 and 22 of power module 1 and supporting capacitor 2 is opposite.

[0033] like Figure 5 As shown, the positive and negative busbars 21 and 22 of the supporting capacitor 2 extend outward along the mounting plane to the positions of bolt 3 and insert 4. The positive and negative busbars 11 and 12 of the power module 1 are bent at least twice, forming a bent shape of the first horizontal plane 13, the vertical plane 14 and the second horizontal plane 15. The power module 1 is connected to the positive and negative busbars of the supporting capacitor 2 on the second horizontal plane 15. The positive and negative busbars 21 and 22 extending from the supporting capacitor 2 are stacked with the positive and negative busbars 11 and 12 of the power module 1 on the second horizontal plane 15, thereby reducing stray inductance by having opposite currents in the positive and negative busbars.

[0034] like Figure 6 As shown, when bolt 3 and insert 4 are installed on power module 1, the positive and negative busbars 21 and 22 of supporting capacitor 2 extend towards power module 1 to the position of bolt 3 and insert 4. The positive and negative busbars 11 and 12 of power module 1 extend horizontally to form a first horizontal surface 13, then bend to form a vertical surface 14, and then bend again to the position of bolt 3 and insert 4 to form a second horizontal surface 15. At the position of bolt 3 and insert 4, the positive and negative busbars 11 and 12 of power module 1 are connected to the positive and negative busbars 21 and 22 of supporting capacitor 2 through bolt 3 and insert 4, so that the current directions of the positive busbars 11 and 21 of power module 1 and supporting capacitor 2 are opposite, and the current directions of the negative busbars 12 and 22 of power module 1 and supporting capacitor 2 are opposite.

[0035] like Figure 7As shown, when the power module 1 and the support capacitor 2 are arranged up and down, the positive and negative busbars 11, 12 of the power module 1 extend horizontally to the positions of the bolts 3 and the inserts 4, the positive and negative busbars 21, 22 of the support capacitor 2 vertically extend from the top surface to form a vertical surface 24, and then are bent to the positions of the bolts 3 and the inserts 4 to form a second horizontal surface 25. At the positions of the bolts 3 and the inserts 4, the positive and negative busbars 11, 12 of the power module 1 are connected with the positive and negative busbars 21, 22 of the support capacitor 2 through the bolts 3 and the inserts 4, so that the current directions of the positive busbars 11, 21 of the power module 1 and the support capacitor 2 are opposite, and the current directions of the negative busbars 12, 22 of the power module 1 and the support capacitor 2 are opposite.

[0036] As shown, the positive and negative busbars between the power module and the support capacitor are connected together through two groups of bolts and inserts, respectively. The current flows from the busbars of the capacitor to the busbars of the power module. The current directions of the busbars at the connection are opposite, the loop area through which the current flows is minimum, that is, S in formula 2 is minimum, and then according to formula 2, the stray inductance L is minimum. Figures 3 to 7

[0037] The structure adjusts the paths and assembly directions of the positive and negative busbars of the power module and the support capacitor, so that the current directions are opposite, the loop area through which the current flows is minimum, that is, S in formula 2 is minimum, and then according to formula 2, the stray inductance L is minimum, so as to reduce the stray inductance of the main loop connected by the power module and the support capacitor. Figure 8 and Figure 9 As shown, the positive and negative busbars of the power module and the positive and negative busbars of the support capacitor are connected through the bolts 3 and the inserts 4. The connection joint surface is parallel to the mounting plane of the power module. The first end part 5 is the connection part of the positive and negative busbars 11, 12 of the power module, and the second end part 6 is the connection part of the positive and negative busbars 21, 22 of the support capacitor. According to the specific mounting position of the power module and the support capacitor, the first end part 5 can also be the connection part of the positive and negative busbars of the support capacitor, and the second end part 6 is the connection part of the positive and negative busbars of the power module. When the current flows from the first end part 5 to the second end part 6, the current direction is as shown. Figure 9 ​The positive busbar 21 of the second end portion 6 is connected with the positive busbar 11 of the first end portion 5, and the negative busbar 22 of the second end portion 6 is connected with the negative busbar 12 of the first end portion 5, to form a three-phase AC inverter main circuit, wherein the positive and negative busbars 21, 22 of the second end portion 6 are bent at least once, part of which is along the vertical direction, and part of which is along the horizontal direction, and the positive and negative busbars 21, 22 of the second end portion 6 are connected with the positive and negative busbars 11, 12 of the first end portion 5 in the horizontal direction; meanwhile, the positive busbar 21 of the second end portion 6 and the negative busbar 12 of the first end portion 5 need to maintain an insulation distance, the part of the positive and negative busbars that is bent and ensures the insulation of the positive and negative busbars is region B, the bolt connection part on the horizontal joint surface is region A, and the bent part of the positive and negative busbars is region C, the negative busbar 12 of the first end portion 5 is connected with the negative busbar 22 of the second end portion 6 through a bolt 3 and an insert 4, the bolt 3 and the insert 4 are close to the negative busbar 12, wherein the current I1 and the current I2 flow through the negative busbar 12, the current I1' flows through the negative busbar 22, the current I2', I3 and I4 flow through the bent part of the negative busbar 22, the current I3' flows through the insert 4, and the current I4' flows through the positive busbar 21, and the specific current directions are shown in Figure 4 ; wherein the current directions of I1 and I1' are opposite, at this time, the loop area through which the current flows is minimum, thereby reducing the stray inductance of region A, the current directions of I2 and I2x' are opposite, I2x' is the component of I2' in the horizontal direction, at this time, the loop area through which the current flows is minimum, thereby reducing the stray inductance of region C, the current directions of I3' and I2z' and I3 are opposite, I2z' is the component of I2' in the vertical direction, at this time, the loop area through which the current flows is minimum, thereby reducing the stray inductance of region B, and the current directions of I4 and I4' are opposite, at this time, the loop area through which the current flows is minimum, thereby reducing the stray inductance of the laminated region of the positive and negative busbars 21, 22 of the second end portion 6; in addition, the principle of reducing the stray inductance of the positive busbar 11 of the first end portion 5 and the positive busbar 21 of the second end portion 6 is the same as that of reducing the stray inductance of the negative busbar 12 of the first end portion 5 and the negative busbar 22 of the second end portion 6. In summary, the structure can solve the problem of excessive stray inductance at the connection between the power module and the supporting capacitor, reduce the stray inductance of region A, region B and region C, thereby reducing the stray inductance of the whole main circuit, reducing the surge voltage caused by the stray inductance, avoiding the danger of breakdown of the power module, ensuring the switching characteristics of the power module, and improving the reliability of motor drive control.

Claims

1. A main circuit layout structure for a three-phase AC motor drive system controller, comprising a power module with positive and negative busbars and a supporting capacitor with positive and negative busbars, wherein the positive busbar of the power module and the positive busbar of the supporting capacitor, and the negative busbar of the power module and the negative busbar of the supporting capacitor, are respectively connected by bolts and inserts to form an inverter main circuit, characterized in that: The positive and negative busbars of the power module extend along the mounting plane to the bolt and insert positions. The positive and negative busbars of the supporting capacitor extend horizontally towards the power module and then bend vertically to the mounting plane of the positive and negative busbars, and then extend along the mounting plane to the bolt and insert positions. The positive and negative busbars of the power module and the positive and negative busbars of the supporting capacitor are stacked in the same direction at the bolt and insert positions, so that the current directions of the positive busbar of the power module and the positive busbar of the supporting capacitor are opposite at the connection point, and the current directions of the negative busbar of the power module and the negative busbar of the supporting capacitor are opposite at the connection point. At this time, the area of ​​the current flowing through the loop is minimized. The positive and negative busbars of the power module and the positive and negative busbars of the supporting capacitor are connected at the bolt and insert positions respectively by bolts and inserts. The positive and negative busbars of the supporting capacitor are bent to form a first horizontal plane, a vertical plane, and a second horizontal plane. The positive and negative busbars of the second horizontal plane are connected to the positive and negative busbars of the power module in the same direction and parallel by bolts and inserts. The bolts and inserts are located near the first horizontal and vertical planes, and the bolts and inserts form opposite current directions with the first horizontal and vertical planes of the connected busbars. At this time, the area of ​​the current flowing through the loop is minimized. The current flow loop area at the connection point between the positive busbar of the power module and the positive busbar of the supporting capacitor is minimized, and the current flow loop area at the connection point between the negative busbar of the power module and the negative busbar of the supporting capacitor is minimized.

2. The main circuit layout structure of the three-phase AC motor drive system controller according to claim 1, characterized in that: The positive and negative busbars of the supporting capacitor are bent to form at least a parallel surface in the same direction as the positive and negative busbars of the power module.

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