Three-level power module and photovoltaic power generation equipment

Abstract

The utility model discloses a three-level power module and photovoltaic power generation equipment. The three-level power module comprises a direct current end, an alternating current end, a plurality of high-frequency switching devices and at least two low-frequency switching devices, the direct-current end is connected with a direct-current power supply or direct-current equipment. The AC end is connected with an AC power supply or AC equipment. Wherein the first end of the low-frequency switching device is connected with the direct-current end through the corresponding high-frequency switching device, and the second end of the low-frequency switching device is connected with the alternating-current end. The low-frequency switching device is arranged at the alternating current end of the three-level power module, so that the junction temperature of the three-level power module can be reduced, the junction temperature balance is improved, and the overall performance of the three-level power module is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of power modules, and in particular, relates to a three-level power module and a photovoltaic power generation device. Background Art

[0002] At present, under the background of global energy transformation and the increase in the proportion of renewable energy power generation, energy storage will show a trend of rapid development. The main function of the energy storage inverter is to convert AC power into DC power or DC power into AC power, and it is a key component of the battery energy storage system. The power module in the inverter is the bridge for the energy storage system and the power grid to realize the two-way flow of energy, and is the core of the inverter. Compared with other inverters, the biggest difference of the energy storage inverter is that it realizes the two-way conversion of AC and DC, so the requirements for the power module are also different.

[0003] Neutral point clamped three-level (NPC) and active neutral point clamped three-level (ANPC) are the mainstream topologies of photovoltaic energy storage inverters. However, the power device loss of NPC three-level inverters is uneven during operation, and some devices have large losses and serious heat generation, resulting in high chip junction temperature, which greatly limits the increase in inverter capacity and power device switching frequency. Utility Model Content

[0004] The purpose of the present application is to provide a three-level power module and a photovoltaic power generation device, aiming to solve the problem of insufficient performance of traditional power modules.

[0005] A first aspect of an embodiment of the present application provides a three-level power module, comprising: a DC end, the DC end being used to connect to a DC power supply or a DC device; an AC end, the AC end being used to connect to an AC power supply or an AC device; a plurality of high-frequency switching devices and at least two low-frequency switching devices, wherein a first end of the low-frequency switching device is connected to the DC end through the corresponding high-frequency switching device, and a second end of the low-frequency switching device is connected to the AC end.

[0006] In one embodiment, the topology structure of the three-level power module is an active neutral point clamped three-level topology structure, and the inner tube in the active neutral point clamped three-level topology structure is a low-frequency switch device.

[0007] In one embodiment, the plurality of high-frequency switch devices include a first high-frequency switch device, a second high-frequency switch device, a third high-frequency switch device and a fourth high-frequency switch device, and the at least two low-frequency switch devices include a first low-frequency switch device and a second low-frequency switch device; a first end of the first high-frequency switch device is connected to the positive pole of the DC end, a second end of the first high-frequency switch device is connected to the first end of the first low-frequency switch device, a second end of the first low-frequency switch device is connected to the AC end, a first end of the second high-frequency switch device is connected to the neutral point of the DC end, and a second end of the second high-frequency switch device is connected to the first end of the first low-frequency switch device; a first end of the third high-frequency switch device is connected to the negative pole of the DC end, a second end of the third high-frequency switch device is connected to the first end of the second low-frequency switch device, a second end of the second low-frequency switch device is connected to the AC end, a first end of the fourth high-frequency switch device is connected to the neutral point of the DC end, and a second end of the fourth high-frequency switch device is connected to the first end of the second low-frequency switch device.

[0008] In one embodiment, the high-frequency switch device is a SiC switch chip, and the low-frequency switch device is an IGBT switch chip.

[0009] In one embodiment, the three-level power module includes a copper-clad substrate and a heat dissipation layer that are stacked; the DC end, the AC end, the high-frequency switching device and the low-frequency switching device are all arranged on the copper-clad substrate.

[0010] In one embodiment, the copper-clad substrate includes a first conductive layer, a support layer, and a second conductive layer stacked in sequence from top to bottom; the DC end, the AC end, the high-frequency switching device, and the low-frequency switching device are all arranged on the first conductive layer, and the heat dissipation layer is arranged on the lower side of the second conductive layer.

[0011] In one embodiment, the heat dissipation layer includes a pin-type heat sink, and the pin-type heat sink is welded on the lower side of the second conductive layer.

[0012] In one embodiment, the material of the support layer includes one or more of Al2O3, AlN and Si3N4.

[0013] In one embodiment, the three-level power module further includes a shell, the shell covers the DC end, the AC end, the high-frequency switch device and the low-frequency switch device, and the shell is filled with silica gel.

[0014] A second aspect of the embodiments of the present application provides a photovoltaic power generation device, comprising the three-level power module as described above.

[0015] Compared with the prior art, the embodiments of the present application have the following beneficial effects: by setting the low-frequency switching device at the AC end of the three-level power module, the junction temperature of the three-level power module can be reduced, the junction temperature balance can be improved, and the overall performance of the three-level power module can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A circuit diagram of a three-level power module provided in an embodiment of the present application;

[0017] Figure 2 A schematic diagram of the structure of a three-level power module provided in an embodiment of the present application;

[0018] Figure 3 A schematic diagram of the structure of a photovoltaic power generation device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0020] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0021] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0022] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0023] Figure 1 A schematic diagram of the structure of a three-level power module provided in an embodiment of the present application is shown. For the sake of convenience, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0024] The three-level power module includes: a DC terminal 100, an AC terminal 200, a plurality of high-frequency switching devices and at least two low-frequency switching devices.

[0025] The DC terminal 100 is used to connect to a DC power supply or a DC device. The AC terminal 200 is used to connect to an AC power supply or an AC device. The first end of the low-frequency switch device is connected to the DC terminal 100 through the corresponding high-frequency switch device, and the second end of the low-frequency switch device is connected to the AC terminal 200.

[0026] It is understandable that the AC-DC conversion of electric energy can be achieved by controlling the on and off of the high-frequency switching device and the low-frequency switching device. The high-frequency switching device has a lower switching loss, so it can perform high-frequency switching, but relatively speaking, the high-frequency switching device generates a large amount of heat when working. The switch tube connected to the AC end 200 usually does not need to perform high-frequency switching. Therefore, the low-frequency switching device is set at the AC end 200 of the three-level power module. By utilizing the low heat generated by the low-frequency switching device, the junction temperature of the three-level power module can be reduced, the junction temperature balance can be improved, and the overall performance of the three-level power module can be improved.

[0027] In one embodiment, if Figure 1 As shown, the topology of the three-level power module is an active neutral point clamped three-level topology (ANPC), and the low-frequency switching device is an inner tube in the active neutral point clamped three-level topology.

[0028] It should be noted that the active neutral point clamped three-level topology structure further includes an outer tube and a clamping switch tube. In this embodiment, the outer tube and the clamping switch tube are both high-frequency switch devices.

[0029] In one embodiment, if Figure 1As shown, the plurality of high-frequency switch devices include a first high-frequency switch device Q1, a second high-frequency switch device Q5, a third high-frequency switch device Q4, and a fourth high-frequency switch device Q6, and the at least two low-frequency switch devices include a first low-frequency switch device Q2 and a second low-frequency switch device Q3. A first end of the first high-frequency switch device Q1 is connected to the positive electrode of the DC terminal 100, a second end of the first high-frequency switch device Q1 is connected to a first end of the first low-frequency switch device Q2, a second end of the first low-frequency switch device Q2 is connected to the AC terminal 200, a first end of the second high-frequency switch device Q5 is connected to the neutral point of the DC terminal 100, and a second end of the second high-frequency switch device Q5 is connected to a first end of the first low-frequency switch device Q2. The first end of the third high-frequency switch device Q4 is connected to the negative electrode of the DC terminal 100, the second end of the third high-frequency switch device Q4 is connected to the first end of the second low-frequency switch device Q3, the second end of the second low-frequency switch device Q3 is connected to the AC terminal 200, the first end of the fourth high-frequency switch device Q6 is connected to the neutral point of the DC terminal 100, and the second end of the fourth high-frequency switch device Q6 is connected to the first end of the second low-frequency switch device Q3. Specifically, in some embodiments, the high-frequency switch device is a silicon carbide metal oxide semiconductor field effect transistor (SiC MOSFET), and the low-frequency switch device is an insulated gate bipolar transistor (IGBT). By providing corresponding control signals to the controlled end of the high-frequency switch device and the controlled end of the low-frequency switch device, the high-frequency switch device and the low-frequency switch device can be controlled to be turned on and off.

[0030] It should be noted that the various switch tubes in this embodiment form an active neutral point clamped three-level topology structure. Among them, the first low-frequency switch device Q2 and the second low-frequency switch device Q3 are both inner tubes of the active neutral point clamped three-level topology structure, the first high-frequency switch device Q1 and the third high-frequency switch device Q4 are both outer tubes of the active neutral point clamped three-level topology structure, and the second high-frequency switch device Q5 and the fourth high-frequency switch device Q6 are both clamping switch tubes of the active neutral point clamped three-level topology structure.

[0031] In the active neutral point clamped three-level topology, the outer tube and the clamping switch tube need to switch at high frequency, so the use of high-frequency switching devices can reduce switching losses, while the switching frequency of the inner tube is low and the current passing through is also large, so the use of low-frequency switching devices can improve the heating of the three-level power module. At the same time, the number of parallel and series high-frequency switching devices can be configured to meet the actual power transmission needs.

[0032] In one embodiment, the high-frequency switch device is a SiC switch chip, and the low-frequency switch device is an IGBT switch chip.

[0033] It can be understood that the SiC switch chip is a chip of a switch tube with silicon carbide (SiC) as the main material. Specifically, in some embodiments, the SiC switch chip is a chip of a silicon carbide metal oxide semiconductor field effect transistor (SiC MOSFET), and the IGBT switch chip is a chip of an insulated gate bipolar transistor (Insulate-Gate Bipolar Transistor; IGBT).

[0034] In one embodiment, if Figure 2 As shown, the three-level power module includes a stacked copper-clad substrate 300 and a heat dissipation layer 400. The DC terminal 100, the AC terminal 200, the high-frequency switching device 500 and the low-frequency switching device 600 are all arranged on the copper-clad substrate 300. Specifically, in some embodiments, the copper-clad substrate 300 is a direct bond copper (DBC) substrate or an active metal bonding (AMB) substrate.

[0035] In one embodiment, the copper clad substrate 300 includes a first conductive layer 310 , a support layer 320 , and a second conductive layer 330 stacked sequentially from top to bottom.

[0036] The DC terminal 100, the AC terminal 200, the high-frequency switch device 500, and the low-frequency switch device 600 are all disposed on the first conductive layer 310, and the heat dissipation layer 400 is disposed on the lower side of the second conductive layer 330. The first conductive layer 310 is used to transmit electrical signals between the DC terminal 100, the AC terminal 200, each high-frequency switch device 500, and each low-frequency switch device 600.

[0037] It can be understood that, in some embodiments, the first conductive layer 310 specifically includes a plurality of copper foils, and the DC end 100, the AC end 200, each high-frequency switch device 500 and each low-frequency switch device 600 are respectively welded on the corresponding copper foils.

[0038] In some embodiments, the DC terminal 100, the AC terminal 200, each high-frequency switch device 500 and each low-frequency switch device 600 may be connected by welding wires such as aluminum wire, copper wire, aluminum strip, copper strip, etc. For example, Figure 2 As shown, the high frequency switch device 500, the low frequency switch device 600 and the corresponding first conductive layer 310 are connected by a copper wire 700.

[0039] In one embodiment, the heat dissipation layer 400 includes a pin-type heat sink, which is welded on the lower side of the second conductive layer 330 .

[0040] For example, Figure 2As shown, the heat dissipation layer 400 includes a heat dissipation plate 410 and a plurality of heat dissipation pins 420 disposed on the heat dissipation plate 410 . The material of the heat dissipation layer 400 may be copper or other thermally conductive materials.

[0041] In one embodiment, the material of the support layer 320 includes one or more of aluminum oxide (Al 2 O 3 ), aluminum nitride (AlN), and silicon nitride (Si 3 N 4 ).

[0042] It should be noted that when the copper-clad substrate 300 is a direct bond copper (DBC) substrate, the material of the support layer 320 is usually aluminum oxide (Al2O3); when the copper-clad substrate 300 is an active metal welding (AMB) substrate, the material of the support layer 320 is usually aluminum nitride (AlN) or silicon nitride (Si3N4). The specific material of the support layer 320 is selected according to specific needs and processes.

[0043] In one embodiment, the three-level power module further includes at least two fast recovery diode (FRD) chips. The fast recovery diodes correspond to the low-frequency switching devices one by one and are connected in parallel with the corresponding low-frequency switching devices.

[0044] In one embodiment, the three-level power module further includes a housing 800 , which is disposed on the DC terminal 100 , the AC terminal 200 , the high-frequency switch device 500 and the low-frequency switch device 600 , and the housing 800 is filled with silica gel.

[0045] The silica gel covering the surface of the DC terminal 100, the AC terminal 200, the high-frequency switch device 500 and the low-frequency switch device 600 can play a role of fixing and protecting, thereby preventing the devices in the three-level power module from falling or being damaged due to external impact.

[0046] In some embodiments, the three-level power module adopts the Easy 2B packaging form to meet the high power requirement of the three-level power module.

[0047] In one embodiment, the DC terminal 100 and the AC terminal 200 both include a plurality of PIN pins 900, which are soldered to the first conductive layer 310 for connection with an external circuit. Specifically, the PIN pins 900 may be an integrated copper pin, an aluminum pin, or a split fish-mouth pin and a copper cap combination pin.

[0048] Figure 3 The following is a schematic diagram of the structure of a photovoltaic power generation device provided by an embodiment of the present application. For the sake of convenience, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0049] The photovoltaic power generation device 20 includes the three-level power module 10 according to any one of the above embodiments. The photovoltaic power generation device 20 performs bidirectional conversion between AC and DC through the three-level power module 10.

[0050] like Figure 1 As shown, the three-level power module 10 includes: a DC terminal 100, an AC terminal 200, a plurality of high-frequency switching devices and at least two low-frequency switching devices. Specifically, in some embodiments, the high-frequency switching device is a silicon carbide metal oxide semiconductor field effect transistor (SiC MOSFET), and the low-frequency switching device is an insulated gate bipolar transistor (IGBT).

[0051] The DC terminal 100 is used to connect to a DC power supply or a DC device. The AC terminal 200 is used to connect to an AC power supply or an AC device. The first end of the low-frequency switch device is connected to the DC terminal 100 through the corresponding high-frequency switch device, and the second end of the low-frequency switch device is connected to the AC terminal 200.

[0052] It is understandable that the AC-DC conversion of electric energy can be achieved by controlling the on and off of the high-frequency switching device and the low-frequency switching device. The high-frequency switching device has a lower switching loss, so it can perform high-frequency switching, but relatively speaking, the high-frequency switching device generates a large amount of heat when working, and the switch tube connected to the AC end 200 usually does not need to perform high-frequency switching. Therefore, the low-frequency switching device is set at the AC end 200 of the three-level power module 10. By utilizing the low heat generated by the low-frequency switching device, the junction temperature of the three-level power module can be reduced, the junction temperature balance can be improved, and the overall performance of the three-level power module 10 can be improved.

[0053] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0054] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0055] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A three-level power module, characterized in that: include: A DC terminal, which is used to connect to a DC power supply or a DC device; An AC terminal, which is used to connect to an AC power source or an AC device; A plurality of high-frequency switching devices and at least two low-frequency switching devices, wherein a first end of the low-frequency switching device is connected to the DC end through the corresponding high-frequency switching device, and a second end of the low-frequency switching device is connected to the AC end.

2. The three-level power module according to claim 1, characterized in that: The topological structure of the three-level power module is an active neutral point clamped three-level topological structure, and the low-frequency switch device is an inner tube in the active neutral point clamped three-level topological structure.

3. The three-level power module according to claim 1, characterized in that: The plurality of high-frequency switch devices include a first high-frequency switch device, a second high-frequency switch device, a third high-frequency switch device and a fourth high-frequency switch device, and the at least two low-frequency switch devices include a first low-frequency switch device and a second low-frequency switch device; The first end of the first high-frequency switch device is connected to the positive electrode of the DC end, the second end of the first high-frequency switch device is connected to the first end of the first low-frequency switch device, the second end of the first low-frequency switch device is connected to the AC end, the first end of the second high-frequency switch device is connected to the neutral point of the DC end, and the second end of the second high-frequency switch device is connected to the first end of the first low-frequency switch device; The first end of the third high-frequency switching device is connected to the negative pole of the DC end, the second end of the third high-frequency switching device is connected to the first end of the second low-frequency switching device, the second end of the second low-frequency switching device is connected to the AC end, the first end of the fourth high-frequency switching device is connected to the neutral point of the DC end, and the second end of the fourth high-frequency switching device is connected to the first end of the second low-frequency switching device.

4. The three-level power module according to claim 1, characterized in that: The high-frequency switch device is a SiC switch chip, and the low-frequency switch device is an IGBT switch chip.

5. The three-level power module according to any one of claims 1 to 4, characterized in that: The three-level power module comprises a copper-clad substrate and a heat dissipation layer which are stacked; The DC end, the AC end, the high-frequency switching device and the low-frequency switching device are all arranged on the copper-clad substrate.

6. The three-level power module according to claim 5, characterized in that: The copper-clad substrate comprises a first conductive layer, a support layer and a second conductive layer stacked in sequence from top to bottom; The DC end, the AC end, the high-frequency switching device and the low-frequency switching device are all arranged on the first conductive layer, and the heat dissipation layer is arranged at the lower side of the second conductive layer.

7. The three-level power module according to claim 6, characterized in that: The heat dissipation layer includes a pin-type heat sink, and the pin-type heat sink is welded on the lower side of the second conductive layer.

8. The three-level power module according to claim 6, characterized in that: The material of the support layer includes one or more of Al2O3, AlN and Si3N4.

9. The three-level power module according to claim 5, characterized in that: The three-level power module further comprises a shell, wherein the shell covers the DC end, the AC end, the high-frequency switch component and the low-frequency switch component, and the shell is filled with silica gel.

10. A photovoltaic power generation device, characterized in that: It comprises a three-level power module as claimed in any one of claims 1 to 9.

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