Converter power module structure and converter

Abstract

The utility model relates to the technical field of converters, in particular to a converter power module structure and a converter. The converter power module structure comprises a capacitor assembly and a power assembly. The capacitor assembly comprises a thin-film capacitor, a capacitor support and a capacitor laminated busbar, the thin-film capacitor is installed on the capacitor support, and the thin-film capacitor is connected with the capacitor laminated busbar; the power assembly comprises a liquid cooling plate, an IGBT module, a power module laminated busbar and a module switching busbar, the IGBT module is arranged on the liquid cooling plate, the IGBT module is connected with the power module laminated busbar, and the module switching busbar and the power module laminated busbar are connected with the capacitor laminated busbar. The capacitor assembly and the power assembly are integrally arranged, so that a commutation loop of the power assembly is shortened, the turn-off overvoltage of a power device is reduced, the cost is reduced, the structure is more compact, the power density is further improved, the safe working area of the converter is expanded, and long-term safe and stable operation of the converter is facilitated.

Description

Technical Field

[0001] The utility model relates to the technical field of converters, and in particular to a converter power module structure and a converter. Background Art

[0002] Converters are widely used in power systems, wind power generation, solar photovoltaics and other fields. They realize bidirectional energy flow in occasions such as peak shaving and valley filling of power grids and energy recycling, actively support the voltage frequency of the power grid, and improve the quality of electric energy. As the requirements for volume and efficiency of converters increase, their electrical structures gradually apply more efficient three-level topologies, and the switching frequency also increases accordingly. The use of high switching frequency and multiple power devices brings problems such as high switching loss and high voltage stress. Therefore, converters have more stringent requirements on the stray inductance parameters of the electrical circuit of the power device module. In order to eliminate the switching loss and shutdown overvoltage problems caused by stray inductance, the stray inductance parameters of the main circuit of the power module are optimized as much as possible.

[0003] At present, the existing stacked busbar power device layout is unreasonable, the thickness of the positive, negative and neutral copper foil inside the busbar is too thick, the stacking area is small, and the height of the crimping terminal of the power device is too high. The suppression effect of stray inductance is not ideal, and the installation process is complicated, which is not conducive to mass production. In addition, due to manufacturing and assembly errors, the gravity of the busbar itself and capacitors, the power devices are subjected to stress. If these factors are not taken into account in the power device layout and stacked busbar design stage, it is likely to cause the power devices to be subjected to excessive stress, especially for three-level converters, whose busbars are generally large and have a large number of capacitors, which increases this risk. Utility Model Content

[0004] The utility model aims at the deficiencies in the prior art and provides a converter power module structure, which solves the problems of unreasonable layout of existing stacked busbar components, unsatisfactory stray inductance suppression effect and complicated installation process, and provides a converter power module structure and a converter.

[0005] The technical solution of the utility model to solve the above technical problems is as follows:

[0006] In the first aspect, the utility model provides a converter power module structure, including a capacitor assembly and a power assembly; the capacitor assembly includes a film capacitor, a capacitor bracket and a capacitor stacked busbar, wherein the film capacitor is installed on the capacitor bracket, and the film capacitor is connected to the capacitor stacked busbar; the power assembly includes a liquid cooling plate, an IGBT module, a power module stacked busbar and a module transfer busbar, the IGBT module is arranged on the liquid cooling plate, the IGBT module is connected to the power module stacked busbar and the module transfer busbar, and the power module stacked busbar is connected to the capacitor stacked busbar.

[0007] Compared with the prior art, the utility model has the following technical effects:

[0008] By dividing the structure of the converter power module into a capacitor component and a power component, the functions of the converter power module are clearly distinguished, which is convenient for installation and maintenance. Due to the obvious functional distinction, it is more conducive to the expansion of power; in the capacitor component, since the film capacitor is installed on the capacitor bracket and the film capacitor is connected to the capacitor stacking busbar, the number of film capacitor components of power units with different powers can be flexibly configured by replacing the capacitor bracket, which enhances the flexible configuration of film capacitors in power units with different power requirements. The IGBT module in the power component is installed on the liquid cooling plate. Since the IGBT module generates high heat when in the working state, the components of the IGBT module are in contact with the liquid cooling plate by fitting with the liquid cooling plate, which accelerates the heat dissipation of the components. Further, the IGBT module is arranged on both sides of the liquid cooling plate; on the one hand, it can optimize the spatial layout of the power module, and the various structures and components are more compact, which is conducive to reducing the overall volume of the power module and improving the power density per unit volume; on the other hand, the heat exchange capacity of the liquid cooling plate can be fully utilized to ensure that the various structures or components of the power component work at a suitable temperature, which is conducive to extending the service life.

[0009] Due to the increased integration of capacitor components and power components, the commutation circuit of the power components can be shortened, which greatly reduces the IGBT turn-off overvoltage and eliminates the du / dt absorption circuit. This reduces costs while making the structure more compact, further improves the power density, and expands the safe operating area of ​​the converter, which is beneficial to the long-term safe and stable operation of the converter.

[0010] On the basis of the above technical solution, the following improvements can be made to the above technical solution:

[0011] Furthermore, it comprises two groups of thin film capacitors, and the two groups of thin film capacitors are connected in parallel.

[0012] The beneficial effects of adopting the above further technical solution are as follows: by setting up film capacitors, the DC voltage can be stabilized and the voltage fluctuation on the DC side can be reduced; and when two groups of film capacitors are connected in parallel, the capacitance values ​​will be added, thereby increasing the overall capacitance value of the circuit, which helps to filter out ripple and noise in the DC voltage and improve the stability of the circuit. The number of film capacitors can be determined according to actual needs. For example, a 710kW power inverter uses 16 film capacitors, and a 630kW power inverter uses 14 film capacitors. The film capacitors are installed on the capacitor bracket in two groups arranged longitudinally; during installation, the film capacitors and the insulating paper at the bottom of the capacitors are installed on the capacitor bracket and pre-tightened by the positioning cover.

[0013] Furthermore, the capacitor stacked busbar adopts a three-layer busbar structure, which includes a capacitor positive busbar, a capacitor N busbar and a capacitor negative busbar. Four insulating layers are added in the middle and outside of the three-layer busbar structure.

[0014] The beneficial effect of adopting the above-mentioned further technical solution is as follows: the capacitor stacked busbar is insulated and stacked, and the capacitor stacked busbar includes a capacitor positive busbar, an N busbar (capacitor zero busbar) and a capacitor negative busbar. The capacitor stacked busbars are stacked and distributed in parallel, with superimposed routing and fewer loops, which is beneficial to reducing the distributed inductance of the line and improving the current carrying capacity of the capacitor stacked busbar.

[0015] Furthermore, the thickness of the capacitor positive busbar is 1 mm, the thickness of the capacitor N busbar is 1.5 mm, and the thickness of the capacitor negative busbar is 1 mm; the thickness of the insulating layer is 0.5 mm.

[0016] Furthermore, the IGBT module comprises a gate plate and an IGBT element. The IGBT element is arranged on the liquid cooling plate through the gate plate. The IGBT element is electrically connected to the gate plate and the module transfer busbar respectively and integrated into one.

[0017] The beneficial effects of adopting the above further technical solution are as follows: the IGBT module has a high degree of integration, which shortens the commutation circuit of the power component, and the optimization of the positive and negative paths of the stacked busbar can effectively reduce the stray inductance, greatly reduce the shutdown overvoltage of the power device, and eliminate the du / dt absorption circuit.

[0018] Furthermore, the module transfer busbar is divided into two layers of busbar structure, namely P busbar and Q busbar, and three insulation layers are added in the middle and outside of the two layers of busbar structure.

[0019] The beneficial effects of adopting the above further technical solution are: placing an insulating layer between the P busbar and the Q busbar to ensure electrical isolation between the two layers of busbars; adding an insulating layer to the outside of each of the two layers of busbars to provide additional electrical isolation and environmental protection.

[0020] Furthermore, the thickness of the P busbar is 1 mm, the thickness of the Q busbar is 1 mm, and the thickness of the insulation layer is 0.5 mm.

[0021] Furthermore, the power module stacked busbar is divided into a three-layer busbar structure, namely a power positive busbar, a power N-pole busbar and a power negative busbar, and a total of four insulating layers are added in the middle and outside of the three-layer busbar structure.

[0022] The beneficial effect of adopting the above further technical solution is that an insulating layer is placed between each layer of the three-layer busbar structure to ensure electrical isolation. In addition, an additional insulating layer may be added to the outside of the entire structure to provide additional protection and safety.

[0023] Furthermore, the thickness of the power positive busbar is 1 mm, the thickness of the power N busbar is 1.5 mm, and the thickness of the power negative busbar is 1 mm; the thickness of the insulation layer is 0.5 mm.

[0024] In a second aspect, the utility model provides a converter, comprising the converter power module structure of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The overall structure of the utility model is shown in FIG. Figure 1 ;

[0026] Figure 2 The overall structure of the utility model is shown in FIG. Figure 2 ;

[0027] Figure 3 It is an axial schematic diagram of the overall structure of the utility model;

[0028] Figure 4 This is a schematic diagram of the structure of the capacitor bracket of the utility model;

[0029] Figure 5 This is a schematic diagram of the capacitor stacked busbar structure of the utility model.

[0030] In the accompanying drawings, the component names represented by the reference numerals are listed as follows:

[0031] 1. First capacitor bracket; 2. Second capacitor bracket; 3. IGBT module; 4. Capacitor stacking busbar; 5. Power module stacking busbar; 6. Module transfer busbar; 7. Liquid cooling plate; 8. First film capacitor. DETAILED DESCRIPTION

[0032] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0033] Reference Figure 1-Figure 5 , a converter power module structure, including a capacitor component and a power component; the capacitor component includes a film capacitor, a capacitor bracket and a capacitor stacked busbar 4, wherein the film capacitor is mounted on the capacitor bracket, and the film capacitor is connected to the capacitor stacked busbar 4; the power component includes a liquid cooling plate 7, an IGBT module 3, a power module stacked busbar 5 and a module transfer busbar 6, and the IGBT module 3 is arranged on the liquid cooling plate 7. Specifically, the IGBT module 3 is arranged on both sides of the liquid cooling plate 7, the IGBT module 3 is respectively connected to the power module stacked busbar 5 and the module transfer busbar 6, and the power module stacked busbar 5 is connected to the capacitor stacked busbar 4.

[0034] By dividing the structure of the converter power module into a capacitor component and a power component, the functions of the converter power module are clearly distinguished, which is convenient for installation and maintenance. Since the functions are clearly distinguished, it is more conducive to the expansion of power; in the capacitor component, since the film capacitor is installed on the capacitor bracket, and the film capacitor is connected to the capacitor stacking busbar 4, the number of film capacitor components of power units with different powers can be flexibly configured by replacing the capacitor bracket, which enhances the flexible configuration of film capacitors in power units with different power requirements. In the power component, the IGBT module 3 is installed on both sides of the liquid cooling plate 7. Since the IGBT module 3 generates high heat when in working state, by fitting with the liquid cooling plate 7, the components of the IGBT module 3 are in contact with the liquid cooling plate 7, which accelerates the heat dissipation of the components. At the same time, the IGBT module 3 is installed on the two surfaces of the liquid cooling plate 7, which makes full use of the heat dissipation effect of the liquid cooling plate 7 and saves space.

[0035] The power components (such as IGBT modules 3, etc.) are integrated, which means that more functional units can be integrated in the same or smaller volume, which effectively reduces the weight of the busbar material used for the stacked busbar, and the total weight of all stacked busbars of the equipment does not exceed 30kg; at the same time, due to the improvement of the integration of the power components, the connection between the power components is tighter, thereby shortening the length of the commutation loop. The stacked busbar is an important part of connecting the power components. The optimization of its path can significantly reduce the stray inductance and improve the stability and efficiency of the system. The reduction of stray inductance means that when the power device is turned off, the induced voltage generated by the inductor will also be reduced accordingly, which helps to protect the power device from damage caused by excessive voltage and prolong its service life. Due to the improvement of integration and the shortening of the commutation loop, the structure is more compact while reducing costs, and the power density is further improved, which is conducive to reducing the user's footprint.

[0036] In this embodiment, two groups of thin film capacitors may be included, namely a first thin film capacitor 8 and a second thin film capacitor, and the two groups of thin film capacitors are connected in parallel. By setting up thin film capacitors, the DC voltage can be stabilized and the voltage fluctuation on the DC side can be reduced; and when the two groups of thin film capacitors are connected in parallel, the capacitance values ​​will be added together, thereby increasing the overall capacitance value of the circuit, helping to filter out ripples and noise in the DC voltage and improving the stability of the circuit. The number of thin film capacitors can be determined according to actual needs. For example, a 710kW power inverter uses 16 thin film capacitors, and a 630kW power inverter uses 14 thin film capacitors. Reference Figure 4 , the film capacitors are installed on the capacitor bracket in two groups arranged vertically. When installing, install the film capacitors and the bottom of the capacitor on the capacitor bracket and pre-tighten them through the positioning cover. For details, refer to Figure 3 The first film capacitor 8 is installed on the first capacitor bracket 1, and the second film capacitor is installed on the second capacitor bracket 2.

[0037] In this embodiment, the capacitor stacked busbar 4 is insulated and stacked, and the capacitor stacked busbar 4 includes a capacitor positive busbar, a capacitor N busbar (capacitor zero busbar) and a capacitor negative busbar. The capacitor positive busbar, the N busbar (capacitor zero busbar) and the capacitor negative busbar pass through an insulating layer. The capacitor stacked busbar 4 is stacked and distributed in parallel, with superimposed routing and fewer loops, which is beneficial to reducing the line distributed inductance and improving the current carrying capacity of the capacitor stacked busbar 4. Figure 2 The connection points of the middle capacitor stacked busbar 4 are marked with "+N" and "N-", which represent the polarity of the film capacitor connected to it. The film capacitor itself has no "+" or "-" polarity and can be installed upside down.

[0038] The capacitor stacked busbar 4 has a three-layer busbar structure and four insulating layers, and the insulating layer thickness is 0.5mm, which is used to isolate the contact problem of each busbar. Among them, the thickness of the capacitor positive busbar is 1mm, the thickness of the capacitor N busbar (capacitor zero busbar) is 1.5mm, and the thickness of the capacitor negative busbar is 1mm.

[0039] The three-layer busbar structure is equipped with 8 wiring terminals, namely the positive busbar incoming terminal, the negative busbar incoming terminal, 2 positive busbar voltage sampling terminals, 2 negative busbar sampling terminals, and 2 N busbar sampling terminals. Figure 5 The capacitor stacked busbar 4 conductive hole groups are arranged with positive electrode holes, N-level holes, N-level holes, and negative electrode holes, respectively, and arranged in sequence, ensuring that the current can flow along a predetermined path while avoiding direct contact between different potentials, thereby ensuring the safety of the system.

[0040] In one embodiment, the positive busbar of the capacitor is provided with a positive busbar incoming line terminal, two positive busbar voltage sampling terminals and a positive hole position. The positive busbar incoming line terminal is used to connect the positive pole of the power supply, and the positive busbar voltage sampling terminal is close to the positive busbar incoming line terminal, and is used to monitor the voltage on the positive busbar; the positive hole position is used for internal connection of the positive busbar. The negative busbar of the capacitor is provided with two N busbar sampling terminals and N-level holes, and the N busbar sampling terminal is used to collect the voltage or current on the neutral point busbar (capacitor N busbar); the N-level hole position is used for internal connection of the N busbar. The negative busbar of the capacitor is provided with a negative busbar incoming line terminal, two negative busbar voltage sampling terminals and a negative hole position. The negative busbar incoming line terminal is opposite to the positive busbar incoming line terminal, and is used to connect the negative pole of the power supply; the negative busbar sampling terminal is usually close to the negative busbar incoming line terminal, and is used to monitor the voltage or current on the negative busbar; the negative hole position is used for internal connection of the negative busbar.

[0041] In one embodiment, the IGBT module 3 includes a gate plate and an IGBT element, the IGBT element is arranged on the liquid cooling plate 7 through the gate plate, and the IGBT element is electrically connected to the gate plate and the module transfer busbar 6 respectively, and the electrical connection between the gate plate and the IGBT element can be established through fasteners (such as bolts and screws), and the electrical connection between the module transfer busbar 6 and the IGBT element can be established through fasteners. It is worth noting that the gate plate is also called the IGBT drive plate, which is a power semiconductor device, widely used in various power equipment such as frequency converters and inverters, and is used to control high voltage and high current switches.

[0042] In this embodiment, the IGBT modules 3 are mirror-imaged on both sides of the liquid cooling plate 7. The number of IGBT modules 3 is 12, with 6 on each side of the liquid cooling plate 7, forming a structure of 2 rows and 3 columns. The liquid cooling plate 7 is mainly used to cool the IGBT module and other surrounding components; the IGBT modules 3 are mirror-imaged on both sides of the liquid cooling plate 7, which, on the one hand, improves the utilization rate of the liquid cooling plate 7 and reduces the weight of the IGBT modules 3; on the other hand, within the same area, increases the power density and reduces the manufacturing cost of the IGBT module.

[0043] In one embodiment, the IGBT module 3 has a heat dissipation substrate on one side close to the liquid cooling plate 7, and the heat dissipation substrate is connected to the liquid cooling plate 7. The heat dissipated by the IGBT module 3 is heat exchanged with the liquid cooling plate 7 through the heat dissipation substrate at the bottom. Optionally, the heat dissipation substrate of the IGBT module 3 is in contact with the liquid cooling plate 7 using a heat conductive material.

[0044] In this embodiment, the IGBT module 3 is electrically connected to the module transfer busbar 6 to achieve efficient transmission and distribution of electric energy; wherein the module transfer busbar 6 is divided into two layers of busbar structure, namely, the P busbar and the Q busbar, the P busbar is a conductive busbar connecting the positive pole of the power supply and the IGBT module, and the Q busbar is mainly used to connect the neutral point (or the neutral potential point) and the IGBT module 3, the P busbar structure thickness is 1mm, the Q busbar structure thickness is 1mm, and three layers of insulation layers are added on the outside, and the insulation layer thickness is 0.5mm, which is used to isolate the contact problem of each busbar. The module transfer busbar 2 is connected in parallel to the DC side of the IGBT, and the three IGBT modules 3 are electrically connected to form a complete three-level structure.

[0045] In this embodiment, the power module stacked busbar 5 is divided into a three-layer busbar structure, namely a power positive busbar, a power N busbar and a power negative busbar. The thickness of the power positive busbar is 1 mm, the thickness of the power N busbar is 1.5 mm, and the thickness of the power negative busbar is 1 mm. Four insulating layers are added in the middle and outside of the three-layer busbar structure. The thickness of the insulating layer is 0.5 mm, which is used to isolate the contact problems of each busbar.

[0046] Specifically, the power module stacked busbar 5 is provided with a plurality of positive pole mounting holes, N-level mounting holes and negative pole mounting holes for mounting the IGBT module 3; the positive pole mounting holes and the negative pole mounting holes are respectively paired with the N-level mounting holes and arranged in a horizontal array, corresponding to three-phase current input.

[0047] Another embodiment of the present invention provides a converter, including the above converter power module structure. The converter provided in this embodiment makes the converter more stable during operation.

[0048] The above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A converter power module structure, characterized in that: It comprises a capacitor assembly and a power assembly; the capacitor assembly comprises a film capacitor, a capacitor bracket and a capacitor stacked busbar, wherein the film capacitor is mounted on the capacitor bracket and the film capacitor is connected to the capacitor stacked busbar; the power assembly comprises a liquid cooling plate, an IGBT module, a power module stacked busbar and a module transfer busbar, and the IGBT module is arranged on both sides of the liquid cooling plate; the IGBT module is connected to the power module stacked busbar and the module transfer busbar, and the power module stacked busbar is connected to the capacitor stacked busbar.

2. A converter power module structure according to claim 1, characterized in that: The invention comprises two groups of film capacitors, which are connected in parallel.

3. The converter power module structure according to claim 1, characterized in that: The capacitor stacked busbar adopts a three-layer busbar structure, which includes a capacitor positive busbar, a capacitor N busbar and a capacitor negative busbar. A total of four insulating layers are added in the middle and outside of the three-layer busbar structure.

4. A converter power module structure according to claim 3, characterized in that: The thickness of the capacitor positive busbar is 1 mm, the thickness of the capacitor N busbar is 1.5 mm, and the thickness of the capacitor negative busbar is 1 mm; the thickness of the insulating layer is 0.5 mm.

5. The converter power module structure according to claim 1, characterized in that: The IGBT module comprises a gate plate and an IGBT element. The IGBT element is arranged on a liquid cooling plate through the gate plate. The IGBT element is electrically connected to the gate plate and the module transfer busbar respectively.

6. The converter power module structure according to claim 1, characterized in that: The module transfer busbar is divided into two layers of busbar structure, namely P busbar and Q busbar, and three insulation layers are added in the middle and outside of the two-layer busbar structure.

7. A converter power module structure according to claim 6, characterized in that: The thickness of the P busbar is 1 mm, the thickness of the Q busbar is 1 mm, and the thickness of the insulation layer is 0.5 mm.

8. The converter power module structure according to claim 1, characterized in that: The power module stacked busbar is divided into a three-layer busbar structure, which includes a power positive busbar, a power N busbar and a power negative busbar. Four insulating layers are added in the middle and outside of the three-layer busbar structure.

9. The converter power module structure according to claim 8, characterized in that: The thickness of the power positive busbar is 1 mm, the thickness of the power N busbar is 1.5 mm, and the thickness of the power negative busbar is 1 mm; the thickness of the insulation layer is 0.5 mm.

10. A converter, characterized in that: The invention comprises a converter power module structure as described in any one of claims 1 to 9.

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