CN109004854B - A power module structure and converter - Google Patents

Abstract

The present invention provides a power module structure and a converter, wherein each DC/DC power module is distributed on both sides of the DC/AC power module; or each DC/AC power module is distributed on both sides of the DC/DC power module; Each DC/AC power module and each DC/DC power module are provided with a positive terminal and a negative terminal; each DC/AC power module and the positive terminal of each DC/DC power module are connected through a positive busbar, and each DC/AC power The module is connected to the negative terminal of each DC/DC power module through the negative busbar. Make the entire commutation loop present a symmetrical structure, no matter if the DC/DC power module or the DC/AC power module is operated alone, their commutation paths are the same, which reduces the stray inductance, avoids the current oscillation of the DC bus, and reduces the The temperature rise of the bus capacitor provides a guarantee for the stable and reliable operation of the centralized virtual synchronization set.

Description

A power module structure and converter

technical field

The invention belongs to the technical field of virtual synchronous machines, and particularly relates to a power module structure and a converter.

Background technique

Large-capacity centralized virtual synchronous machines are generally required to be above the MW level, the primary side AC input is AC35kV or 10kV voltage, and the secondary side output DC voltage is connected to the battery system. Based on the current battery manufacturing level, the maximum voltage of the battery system is generally below DC1000V. The AC side of the virtual synchronous machine is directly connected to the grid or connected to the grid through an isolation transformer, and the DC side is connected to two or more battery packs. The converter generally adopts a topology of more than 2 levels to meet the application requirements, such as 1-level DC/AC power module + 1-level DC/DC power module.

Both DC/AC power modules and DC/DC power modules are composed of IGBTs and other devices. As the core component of the converter, IGBT power modules are widely used in various fields. The existing IGBT power modules usually adopt an integrated design to dissipate heat. IGBT, supporting capacitor, DC busbar, gate drive board, pulse distribution board, temperature relay and other components are integrated together to form an independent functional unit structure, which can complete current conversion functions such as rectification, inverter or chopper. , and can be installed and removed from the converter as a separate component. The existing DC/DC power module and DC/AC power module do not have a specific placement structure. In the existing design, the DC/DC power module and the DC/AC power module often use an asymmetric structure, which is caused by the asymmetry of the topology. The commutation paths of the power modules are inconsistent. During the operation of the converter, the DC bus current will oscillate, resulting in inconsistent temperature rise of the bus capacitors, reducing the service life of the virtual synchronous machine, and in severe cases, causing the temperature of the DC bus capacitors. Above 90°C, exceeding the allowable temperature range of the capacitor, resulting in thermal damage to the bus capacitor.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a power module structure and a converter, which are used to solve the problem that the unreasonable structural arrangement of the power module causes the DC bus to oscillate in the prior art.

In order to achieve the above object, the present invention provides a power module structure, including at least two DC/DC power modules and at least two DC/AC power modules, each DC/AC power module is centrally arranged side by side, and each DC/DC power module Distributed on both sides of the DC/AC power module; or, each DC/DC power module is centrally arranged side by side, and each DC/AC power module is distributed on both sides of the DC/DC power module; A positive terminal and a negative terminal are arranged on the DC power modules; the positive terminals of each DC/AC power module and each DC/DC power module are connected through a positive busbar, and each DC/AC power module is connected to the negative terminal of each DC/DC power module. The terminals are connected through the negative busbar.

As a further limitation on the positive electrode busbar and the negative electrode busbar, the positive electrode busbar and the negative electrode busbar are arranged overlappingly.

Further, the positive terminal and negative terminal of each DC/DC power module are arranged in the same manner; the positive terminal and negative terminal of each DC/AC power module are arranged in the same manner; the positive terminal and negative terminal of the DC/DC power module are arranged in the same manner. The arrangement is opposite to that of the positive terminal and negative terminal of the DC/AC power module. The positive terminal is connected to the fixed terminal; the negative terminal is provided with the negative terminal corresponding to the negative terminal position of each DC/DC power module and DC/AC power module.

Further, groove structures are symmetrically opened on both sides of the positive electrode busbar and the negative electrode busbar.

Further, the trough structure is oval.

The present invention also provides a converter, including a power module structure, the power module structure includes at least two DC/DC power modules and at least two DC/AC power modules, and the DC/AC power modules are centrally arranged side by side, The DC/DC power modules are distributed on both sides of the DC/AC power module; or, the DC/DC power modules are centrally arranged side by side, and the DC/AC power modules are distributed on both sides of the DC/DC power module; A positive terminal and a negative terminal are provided on the power module and each DC/DC power module; the positive terminal of each DC/AC power module and each DC/DC power module are connected through a positive busbar, and each DC/AC power module is connected to each DC/DC power module. The negative terminal of the /DC power module is connected via the negative busbar.

As a further limitation on the positive electrode busbar and the negative electrode busbar, the positive electrode busbar and the negative electrode busbar are arranged overlappingly.

Further, the positive terminal and negative terminal of each DC/DC power module are arranged in the same manner; the positive terminal and negative terminal of each DC/AC power module are arranged in the same manner; the positive terminal and negative terminal of the DC/DC power module are arranged in the same manner. The arrangement is opposite to that of the positive terminal and negative terminal of the DC/AC power module. The positive terminal is connected to the fixed terminal; the negative terminal is provided with the negative terminal corresponding to the negative terminal position of each DC/DC power module and DC/AC power module.

Further, groove structures are symmetrically opened on both sides of the positive electrode busbar and the negative electrode busbar.

Further, the trough structure is oval.

The beneficial effects of the present invention are:

The power module structure of the present invention distributes each DC/DC power module on both sides of the DC/AC power module; or each DC/AC power module is distributed on both sides of the DC/DC power module; each DC/AC power module is connected to Each DC/DC power module is provided with a positive terminal and a negative terminal; each DC/AC power module is connected to the positive terminal of each DC/DC power module through a positive busbar, and each DC/AC power module is connected to each DC/DC The negative terminal of the power module is connected via the negative busbar. Make the entire commutation loop present a symmetrical structure, no matter whether the DC/DC power module or the DC/AC power module is operated alone, their commutation paths are consistent, which reduces the stray inductance, avoids the current oscillation of the DC bus, and reduces the The temperature rise of the bus capacitor provides a guarantee for the stable and reliable operation of the centralized virtual synchronization set.

Description of drawings

Figure 1 is a schematic diagram of a centralized virtual synchronous machine 2-level topology DC/DC+DC/AC;

Figure 2 is a schematic diagram of the layout structure of the power module and the DC busbar;

FIG. 3 is a schematic diagram of the structure corresponding to the positive and negative electrode overlapping busbars, the positive electrode busbar and the negative electrode busbar in order from top to bottom.

Detailed ways

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings:

The invention provides a converter, the converter includes a power module structure, the power module structure includes at least two DC/DC power modules and at least two DC/AC power modules, and the DC/AC power modules are centrally arranged side by side, The DC/DC power modules are distributed on both sides of the DC/AC power module; or, the DC/DC power modules are centrally arranged side by side, and the DC/AC power modules are distributed on both sides of the DC/DC power module; A positive terminal and a negative terminal are provided on the power module and each DC/DC power module; the positive terminal of each DC/AC power module and each DC/DC power module are connected through a positive busbar, and each DC/AC power module is connected to each DC/DC power module. The negative terminal of the /DC power module is connected via the negative busbar.

Further, in this embodiment, the positive terminal and negative terminal of each DC/DC power module are arranged in the same manner; the positive terminal and negative terminal of each DC/AC power module are arranged in the same manner; the positive terminal of the DC/DC power module is arranged in the same manner; The arrangement of terminals and negative terminals is opposite to that of the positive terminals and negative terminals of the DC/AC power module; on the positive busbar, there is a location corresponding to the positive terminal of each DC/DC power module and DC/AC power module. The corresponding positive pole is connected to the fixed terminal; the negative pole busbar is provided with a negative pole connected to the fixed terminal corresponding to the position of the negative terminal of each DC/DC power module and DC/AC power module. Slot structures are symmetrically opened on both sides of the positive electrode busbar and the negative electrode busbar, and the positive electrode busbar and the negative electrode busbar in this embodiment are in a stacked arrangement structure.

Specifically, as shown in FIG. 1 , the centralized virtual synchronous machine includes a two-pole topology structure of DC/DC power module+DC/AC power module. DC/DC power modules and DC/AC power modules can have multiple inputs, as shown in Figure 2, including three DC/AC power modules and two DC/DC power modules, and the three DC/AC power modules are placed in sequence in In the middle position, the DC/DC1 and DC/DC2 power modules are placed on both sides of the DC/AC power module, and the entire circulation loop presents a symmetrical structure. The commutation paths are the same for both DC/AC power modules. In order to meet the expansion requirements, for example, when expanding a 2-channel DC/DC power module into a 4-channel DC/DC power module, only one DC/DC power module needs to be added on each side of the DC/DC power module.

The positive pole of the DC/DC power module in the power module structure and the positive pole of the DC/AC power module are both connected to the positive pole of the DC busbar, and the negative pole of the DC/DC power module and the negative pole of the DC/AC power module are both connected to the DC busbar. The negative busbar of the DC/AC power module is connected, the positive pole of the DC/AC power module is above the power module, and the negative pole is below the power module. The positive pole of the DC/DC power module is below the power module, and the negative pole is above the power module. The staggered arrangement of the positive and negative poles of the DC/DC power module and the DC/AC power module makes the inflowing current of the busbar capacitor on the side closer to the busbar subject to a certain resistance, so that the current flowing from the DC capacitor busbar first passes through the stack. The wider area on the layer busbar flows into the center of each DC/DC power module, and then flows to the input end of each DC/DC power module, so that the current flowing in the DC busbar of each DC/DC power module is basically the same, effective It improves the current sharing characteristics between the DC/DC power modules, reduces the stray inductance to a minimum, ensures the consistency of the bus capacitor current of each power module, and avoids the oscillation of the DC bus current.

As shown in Figure 3, the positive and negative busbars are placed through insulating layers, which are strictly symmetrical, and the thickness of the insulating material of the positive and negative busbars is both 2mm.

In order to balance the currents on the positive and negative busbars flowing into the DC bus capacitor busbars, there are symmetrical oval slotted structures on the positive and negative busbars. When there is no slot around the mounting holes of the positive and negative busbars, the positive current and the negative current are staggered when viewed from the up and down direction of the laminated busbar; and the current flowing from the DC bus capacitor busbar will vary according to the The principle of low impedance goes directly to the closer path. Therefore, the current flowing into the positive and negative bus capacitors is inconsistent, resulting in uneven current flowing through each DC/DC power module, inconsistent impedance, and causing bus current resonance. After the positive and negative busbars are slotted, both the positive and negative currents are shunted by the oval slot. Viewed from the upper and lower directions of the laminated busbar, the shunted positive and negative currents overlap, thereby reducing stray inductance. . Moreover, the current paths flowing into the positive and negative poles of the DC/DC power modules are basically the same, so that the positive and negative currents of each DC/DC power module are consistent, and the stray inductance of the busbar is reduced to the greatest extent. Therefore, the laminated busbar design of this embodiment not only has the characteristics of strong anti-interference ability, good reliability, and space saving, but also greatly reduces the stray inductance. The slotted structure in this embodiment is an ellipse, which is a preferred way, and as another embodiment, it can also be designed as a circle.

In this embodiment, the DC/AC power module is placed in the middle position, and the DC/DC power module is placed on both sides of the DC/AC power module. The AC power module is placed on both sides of the DC/DC power module. Since it is only a structural change, its related working principle is basically the same as the above description. Therefore, the related working principle of placing the DC/DC power module in the middle position is here. No longer.

The high-voltage DC/AC power module in this embodiment can be changed from an MMC topology to a bidirectional full-bridge power module, and the DC/DC power module can be changed from a bidirectional LLC converter to an LC resonant converter, etc.

The gist of the present invention is that the DC/DC power modules are symmetrically placed on both sides of the DC/AC power module, or the DC/AC power modules are symmetrically arranged on both sides of the DC/DC power module. The stray inductance can effectively suppress the busbar capacitance oscillation; further, the stray inductance is reduced to a greater extent through the design of the laminated busbar, which ensures the stable and reliable operation of the virtual synchronous generator.

The specific embodiments are given above, but the present invention is not limited to the above-described embodiments. The basic idea of the present invention lies in the above-mentioned basic scheme. For those of ordinary skill in the art, according to the teachings of the present invention, it does not require creative work to design various deformed models, formulas, and parameters. Changes, modifications, substitutions and deformations made to the embodiments without departing from the principle and spirit of the present invention still fall within the protection scope of the present invention.

Claims (6)

1. A power module structure is characterized by comprising at least two DC/DC power modules and at least two DC/AC power modules, wherein the DC/AC power modules are arranged in a centralized and parallel mode and are distributed on two sides of the DC/AC power modules; or the DC/DC power modules are arranged in a centralized and parallel mode, and the DC/AC power modules are distributed on two sides of the DC/DC power modules; positive terminals and negative terminals are arranged on each DC/AC power module and each DC/DC power module; each DC/AC power module is connected with the positive terminal of each DC/DC power module through a positive busbar, and each DC/AC power module is connected with the negative terminal of each DC/DC power module through a negative busbar;

the positive busbar and the negative busbar are arranged in an overlapping manner;

the positive terminal and the negative terminal of each DC/DC power module are arranged in the same mode; the positive terminal and the negative terminal of each DC/AC power module are arranged in the same mode; the arrangement mode of the positive terminal and the negative terminal of the DC/DC power module is opposite to that of the positive terminal and the negative terminal of the DC/AC power module; the positive electrode busbar is provided with positive electrode connecting fixed ends corresponding to the positions of positive electrode terminals of the DC/DC power modules and the DC/AC power modules; and the negative electrode busbar is provided with a negative electrode connecting fixed end corresponding to the positions of the negative electrode terminals of the DC/DC power modules and the DC/AC power modules.

2. The power module structure of claim 1, wherein the positive busbar and the negative busbar are symmetrically provided with groove structures at two sides.

3. The power module structure of claim 2 wherein the slot-type structure is oval-shaped.

4. The converter is characterized by comprising a power module structure, wherein the power module structure comprises at least two DC/DC power modules and at least two DC/AC power modules, the DC/AC power modules are arranged in a centralized and parallel mode, and the DC/DC power modules are distributed on two sides of the DC/AC power modules; or the DC/DC power modules are arranged in a centralized and parallel mode, and the DC/AC power modules are distributed on two sides of the DC/DC power modules; positive terminals and negative terminals are arranged on each DC/AC power module and each DC/DC power module; each DC/AC power module is connected with the positive terminal of each DC/DC power module through a positive busbar, and each DC/AC power module is connected with the negative terminal of each DC/DC power module through a negative busbar;

the positive busbar and the negative busbar are arranged in an overlapping manner;

the positive terminal and the negative terminal of each DC/DC power module are arranged in the same mode; the positive terminal and the negative terminal of each DC/AC power module are arranged in the same mode; the arrangement mode of the positive terminal and the negative terminal of the DC/DC power module is opposite to that of the positive terminal and the negative terminal of the DC/AC power module; the positive electrode busbar is provided with positive electrode connecting fixed ends corresponding to the positions of positive electrode terminals of the DC/DC power modules and the DC/AC power modules; and the negative electrode busbar is provided with a negative electrode connecting fixed end corresponding to the positions of the negative electrode terminals of the DC/DC power modules and the DC/AC power modules.

5. The converter according to claim 4, wherein the positive busbar and the negative busbar are symmetrically provided with groove-shaped structures at two sides.

6. The current transformer of claim 5, wherein the slot-type structure is oval.

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