阅读说明：本技术 基于大功率igbt并联的高压电气连接方法及结构 (High-voltage electrical connection method and structure based on high-power IGBT parallel connection ) 是由 李守蓉 王雷 李萍 肖轲远 于 2020-12-21 设计创作，主要内容包括：本发明为解决由于功率模块本身或者外部接口限制导致用于IGBT并联时复合母排并联支路存在固有不均衡性问题导致IGBT并联工作出现不同步性技术问题,提供一种基于大功率IGBT并联的高压电气连接方法及结构。一种基于大功率IGBT并联的高压电气连接方法,针对安装有一对并联IGBT组件的复合母排,引入两组外部电阻,每组外部电阻顺次与复合母排以及一个IGBT组件串联,构成一路高压电气连接电路,两路高压电气连接电路并联；调整每组外部电阻的阻值,减少分配在IGBT组件上的电流比例,使得两路高压电气连接电路达到均流。本发明将并联的IGBT的不平衡性转移至线路中,而不是落在IGBT上,有效减少功率模块上复合母排由于空间问题造成设计不同步的难度。(The invention provides a high-voltage electrical connection method and structure based on high-power IGBT parallel connection, aiming at solving the technical problem that the intrinsic imbalance problem of a composite busbar parallel branch is caused when the composite busbar parallel branch is used for IGBT parallel connection due to the limitation of a power module or an external interface, so that the asynchronization of the IGBT parallel operation is caused. A high-voltage electrical connection method based on high-power IGBT parallel connection is characterized in that two groups of external resistors are introduced for a composite bus bar provided with a pair of parallel IGBT components, each group of external resistors are sequentially connected with the composite bus bar and one IGBT component in series to form a high-voltage electrical connection circuit, and the two high-voltage electrical connection circuits are connected in parallel; the resistance value of each group of external resistors is adjusted, the current proportion distributed on the IGBT assembly is reduced, and the two paths of high-voltage electric connection circuits achieve current sharing. The invention transfers the unbalance of the parallel IGBT into the circuit instead of falling on the IGBT, thereby effectively reducing the difficulty of asynchronous design of the composite busbar on the power module caused by space problems.)

1. A high-voltage electrical connection method based on high-power IGBT parallel connection is characterized in that two groups of external resistors are introduced for a composite busbar provided with a pair of parallel IGBT components, and each IGBT component is provided with at least one IGBT tube; each group of external resistors are sequentially connected in series with the composite busbar and one IGBT assembly to form a high-voltage electrical connection circuit, and the two high-voltage electrical connection circuits are connected in parallel; the resistance value of each group of external resistors is adjusted, the current proportion distributed on the IGBT assembly is reduced, and the two paths of high-voltage electric connection circuits achieve current sharing.

2. The high-power IGBT parallel connection-based high-voltage electrical connection method according to claim 1, characterized in that under the condition that two high-voltage electrical connection circuits achieve current sharing, IGBT tubes with consistent parameters are selected.

3. The high-power IGBT parallel connection-based high-voltage electrical connection method as claimed in claim 1, wherein each IGBT assembly is composed of one IGBT tube, or each IGBT assembly is composed of two or more IBGT tubes connected in series.

4. The high-voltage electrical connection method based on the parallel connection of the high-power IGBTs as claimed in any one of claims 1 to 3, wherein the resistance values of the two groups of introduced external resistors are controlled according to the temperature rise during operation, and the temperature rise is controlled within 30K.

5. A high-voltage electrical connection structure based on high-power IGBT parallel connection is used for realizing the high-voltage electrical connection method based on high-power IGBT parallel connection of claim 1, and is characterized by comprising a pair of copper bars and a composite busbar on which a pair of IGBT components are mounted in parallel; each group of IGBT assemblies comprises at least one IGBT tube; the pair of copper bars are symmetrically arranged at one end of the composite busbar.

6. The high-power IGBT parallel connection-based high-voltage electrical connection structure as claimed in claim 5, wherein each group of IGBT assemblies is formed by at least two IGBT tubes connected in series.

7. The high-power IGBT parallel connection-based high-voltage electrical connection structure as claimed in claim 5, wherein each group of IGBT assemblies consists of one IGBT tube.

8. The high-voltage electrical connection structure based on the high-power IGBT parallel connection as claimed in any one of claims 5 to 7, wherein the copper bar is composed of an L-shaped section and a mounting section; the vertical part of the L-shaped section is connected to one end of the horizontal part, a mounting hole connected with the composite busbar is formed in the vertical part, the mounting section is perpendicular to the plane where the L-shaped section is located and is connected to the other end of the horizontal part of the L-shaped section, and a mounting hole is formed in the mounting section.

9. The high-power IGBT parallel high-voltage electrical connection structure as claimed in any one of claims 5 to 7, wherein the resistance value of the copper bar is controlled according to the temperature rise during operation, and the temperature rise is controlled within 30K.

10. The high-power IGBT parallel connection-based high-voltage electrical connection structure as claimed in claim 9, wherein the resistance of the copper bar is controlled by controlling the length of the copper bar, so that the temperature rise of the copper bar is controlled within 30K.

Technical Field

The invention relates to a composite busbar technology of a high-power alternating-current transmission traction auxiliary converter system, in particular to a high-power IGBT parallel connection-based high-voltage electrical connection method and structure.

Background

The composite busbar technology is widely applied to the main circuit connection of a high-power alternating-current transmission traction auxiliary converter system, can reduce stray inductance in an electric main circuit, improves the working reliability of a power device, saves space, and enables the power unit connection to be more compact and concise.

Particularly, in a railway locomotive or motor car traction system, because the output power is high, the required system input current is large, a single IGBT cannot meet the system requirement, and two IGBTs are often required to be connected in parallel to complete the rectification work. When two IGBTs work in parallel, the work synchronism of the parallel IGBTs needs to be considered, and the working of the parallel IGBTs is directly influenced by the synchronism of a composite busbar electrically connected with an IGBT main circuit. Generally, the parallel composite busbar design method is to externally provide an alternating current output terminal and internally connect two parallel IGBTs. The design method is suitable for separating the alternating current output terminal and the direct current terminal of the composite busbar from each other and not installing the composite busbar on the same side, but the cabinet body structure of the converter system often requires that all the connecting terminals of the composite busbar are on the same side due to the requirements of a main circuit and an interface, namely the alternating current terminal and the direct current terminal of the composite busbar are on the same side; and the parallel connection method makes the high synchronism requirement of the IGBT parallel current fall on the composite busbar and the IGBT of the power unit, thereby greatly increasing the parallel connection design requirement of the composite busbar of the power unit and the IGBT parameter matching requirement.

In particular, the prior art has the following disadvantages: as shown in fig. 1 and 2, the high-voltage electrical connection of the parallel IGBTs is completed by a composite busbar of the power module. The high-voltage electrical connector with the IGBTs connected in parallel is designed on a composite bus bar of the power module, the composite bus bar is connected with the two IGBTs, and only one output terminal is arranged. The shunt-wound current-sharing performance of the IGBT is completely determined by the composite busbar. If the parameter matching and the parallel design performance of the composite busbar are poor, the reliability of the parallel operation of the IGBTs is influenced, so that the synchronism of the parallel operation of the IGBTs needs to be considered besides the requirements on temperature rise and installation in the design of the rectifying composite busbar, and the design difficulty and the cost are greatly increased.

Disclosure of Invention

The invention provides a high-voltage electrical connection method and structure based on high-power IGBT parallel connection, aiming at solving the technical problem that the intrinsic imbalance problem of a composite busbar parallel branch is caused when the composite busbar parallel branch is used for IGBT parallel connection due to the limitation of a power module or an external interface, so that the asynchronization of the IGBT parallel operation is caused.

The high-voltage electrical connection method based on the high-power IGBT parallel connection is realized by adopting the following technical scheme: a high-voltage electrical connection method based on high-power IGBT parallel connection is characterized in that two groups of external resistors are introduced aiming at a composite bus bar provided with a pair of parallel IGBT components, and each IGBT component is provided with at least one IGBT tube; each group of external resistors are sequentially connected in series with the composite busbar and one IGBT assembly to form a high-voltage electrical connection circuit, and the two high-voltage electrical connection circuits are connected in parallel; the resistance value of each group of external resistors is adjusted, the current proportion distributed on the IGBT assembly is reduced, and the two paths of high-voltage electric connection circuits achieve current sharing.

Fig. 1 and 3 are electrical schematic diagrams of the conventional scheme and the parallel connection of the IGBTs of the present invention, the synchronization of the parallel connection of the IGBTs has a relationship with the parameters of the line, and the parameters of any line can be composed of resistance and inductance, so that the electrical principles of fig. 1 and 3 can be simplified into a mathematical model, as shown in fig. 4 and 5. It can be seen that the synchronism is related to the resistance and inductance balance of the line, and the composite busbar of the power module is only a part of the whole parallel branch. If because the restriction of structure and interface, two branch road differences of compound female arranging certainly exist, in order to reduce the influence of unbalanced line to IGBT parallel operation, can shift the unbalance to the circuit in, rather than falling on the IGBT. The parallel connection current-sharing performance of the IGBTs is not limited to the design and the work of the power module, the electric connection of the whole current conversion system is considered, and the parallel connection work reliability of the IGBTs is reduced and considered in the electric connection design of the system.

The imbalance of the current of the parallel branch can be represented by the imbalance of the resistance and the inductance, and the current of the parallel branch in a steady state is shown as the formula (1):

the traditional IGBT synchronism parameters are related to the composite busbar of the power unit and parameters of an IGBT device, and the parallel synchronism change can be caused by mismatching of the composite busbar or the IGBT characteristic parameters.

If the more factors influencing the parallel connection in the line are, the larger the parameter value is, the smaller the proportion distributed to the IGBTs is, i.e. when the imbalance of the two parallel branches is calculated, the smaller the proportion of the IGBTs is, as shown in the above formula (2). According to the connecting method, the converter connecting copper bars Rl are arranged in the two IGBT parallel branches as a factor influencing different properties of the parallel IGBTs. Resistance of copper barThe resistivity rho, the length l and the cross section area s of the copper bar are related. The longer the copper bar length is, the larger the cross-sectional area of the current flowing through the copper bar is, the larger the resistance value of the copper bar is, and the smaller the non-uniform current property of the parallel connection is reflected on the IGBT. Certainly, the resistance value of connecting the copper bar is too big, can lead to the copper bar during operation to generate heat more highly, generally controls the copper bar temperature rise within 30K.

The method meets the installation requirement of the composite busbar, meets the convenience of part maintenance, and greatly reduces the difficulty of parallel design of the composite busbar of the power module.

In the above formula I₁、I₂The currents flowing through two (group) IGBTs are respectively, I is the total current, Rl1 and Rl2 are introduced external resistors (such as copper bars and external resistors)Resistance is the embodiment of a mathematical model of the copper bar), Rb1 and Rb2 are respectively the resistance of the composite busbar part connected with the two (group) IGBTs, and RT1 and RT2 are respectively the resistance of the two (group) IGBTs.

The high-voltage electrical connection structure based on the high-power IGBT parallel connection is realized by adopting the following technical scheme: a high-voltage electrical connection structure based on high-power IGBT parallel connection is used for realizing a high-voltage electrical connection method based on high-power IGBT parallel connection and comprises a pair of copper bars and a composite busbar on which a pair of IGBT components are mounted in parallel; each group of IGBT assemblies comprises at least one IGBT tube; the pair of copper bars are symmetrically arranged at one end of the composite busbar.

According to the invention, by introducing the pair of copper bars, the unbalance of the parallel IGBT is transferred to a line (the copper bars and the composite bus bars) instead of falling on the IGBT, so that the difficulty of asynchronous design of the composite bus bars on the power module caused by space problems is effectively reduced.

Drawings

Fig. 1 is a schematic diagram (circuit diagram) of a conventional parallel electrical connection method of IGBTs.

Fig. 2 is a schematic diagram (physical diagram) of a conventional parallel electrical connection method of IGBTs.

FIG. 3 is an electrical schematic of the method of the present invention.

Fig. 4 is a conventional mathematical model of a high voltage electrical connection.

Fig. 5 is a mathematical model of the electrical connection method of the present invention.

Fig. 6 is a schematic diagram of the installation of high voltage electrical connections of parallel IGBT power modules.

Fig. 7 is a schematic diagram of a high-voltage electrical connection method for parallel connection of conventional IGBTs.

FIG. 8 is a schematic diagram of a high voltage electrical connection designed in accordance with the present invention.

1-copper bar and 2-composite bus bar.

Detailed Description

As shown in fig. 6, the invention designs a high-voltage electrical connection structure based on parallel connection of high-power IGBTs, which is composed of a pair of copper bars and a composite busbar on which a pair of IGBT components are mounted in parallel; each group of IGBT assemblies comprises at least one IGBT tube; the pair of copper bars are symmetrically arranged at one end of the composite busbar.

Each group of IGBT assemblies is formed by connecting at least two IGBT tubes in series, or each group of IGBT assemblies is formed by one IGBT tube.

As shown in fig. 8, the copper bar is composed of an L-shaped section and a mounting section; the vertical part of the L-shaped section is connected to one end of the horizontal part, a mounting hole connected with the composite busbar is formed in the vertical part, the mounting section is perpendicular to the plane where the L-shaped section is located and is connected to the other end of the horizontal part of the L-shaped section, and a mounting hole is formed in the mounting section.

The resistance value of the copper bar is controlled according to the temperature rise during operation, and the temperature rise is controlled within 30K.

The temperature rise of the copper bar is controlled by controlling the length of the copper bar, and then the resistance of the copper bar is controlled to a reasonable numerical value.

Fig. 7 shows the connection manner of the copper bar and the composite bus bar when the conventional IGBTs are connected in parallel, and it can be seen from the figure that the asynchronism of the parallel connection of the IGBTs is directly reflected in the current flow direction of the composite bus bar, as shown by the black arrow lines. Fig. 8 shows the connection mode of the copper bar and the composite bus bar when the IGBTs according to the present invention are connected in parallel, and the dotted arrow indicates the current flow direction. It can be seen that the parallel IGBTs are completely symmetrical and synchronous from the beginning of the connection of the copper bars, and the asynchronism of the IGBTs can be distributed on the copper bars and the composite busbar, so that the difficulty of design asynchronism of the composite busbar on the power module due to space problems is reduced.