Power module, conversion device and photovoltaic inverter

Abstract

The invention discloses a power module, a conversion device and a photovoltaic inverter, and relates to the technical field of semiconductor power devices, and the power module comprises a ceramic substrate, a power switch tube, a semiconductor diode, a thermistor and a sealing layer. Wherein the power switch tube is arranged on the ceramic substrate and is provided with a plurality of switch pins; the semiconductor diode is arranged on the ceramic substrate, and the anode of the semiconductor diode is electrically connected with one switch pin; the thermistor is arranged on the ceramic substrate and is positioned between the power switch tube and the semiconductor diode; the sealing layer covers the power module. The power module provided by the invention has the effects of reducing the installation difficulty of the power device and reducing related process steps.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor power devices, and in particular to a power module, a conversion device and a photovoltaic inverter. Background Art

[0002] At present, power devices, as core components in power electronics systems, are widely used in new energy vehicles, renewable energy power generation, industrial automation and other fields.

[0003] However, in the related art, since the heat sink on the back of the power device is charged, an insulating gasket is required during installation. Moreover, a large number of power devices are usually required to be installed when the power device is installed and used. Each power device needs to be matched with an insulating gasket or multiple power devices need to be matched with a larger insulating gasket. The large number of power devices and corresponding insulating gaskets will not only increase the cost, but also make the installation of the power device inconvenient. Summary of the invention

[0004] The purpose of the present application is to solve at least one of the technical problems existing in the prior art, and to provide a power module, a conversion device and a photovoltaic inverter, aiming to reduce the difficulty of installing power devices and reduce related process steps.

[0005] In a first aspect, an embodiment of the present application provides a power module, including a ceramic substrate, a power switch tube, a semiconductor diode, a thermistor and a sealing layer; The power switch tube is arranged on the ceramic substrate and has a plurality of switch pins; The semiconductor diode is disposed on the ceramic substrate, and an anode of the semiconductor diode is electrically connected to one of the switch pins; The thermistor is arranged on the ceramic substrate and located between the power switch tube and the semiconductor diode; The sealing layer covers the power module.

[0006] According to the technical solution of the embodiment of the present application, at least the following beneficial effects are achieved: the ceramic substrate has not only good electrical properties but also insulation properties, so the power module is not charged when installed, which can avoid the trouble of installing an additional insulating gasket when the heat sink on the back of the power module is charged, and the ceramic substrate also has a certain heat dissipation performance, which is beneficial to the heat dissipation of the power module; the power switch tube and the semiconductor diode electronic components in the power module are integrated into one, which can reduce the difficulty of installing the power device and reduce the related process steps, and reduce the cost of the power module; the thermistor is arranged on the ceramic substrate and between the power switch tube and the semiconductor diode, so that the thermistor can monitor the temperature of the power switch tube and the semiconductor diode at the same time, thereby improving the practicality of the temperature detection function; when the power module is installed, one side of the power module on which the power element is arranged contacts the heat sink of the peripheral device, that is, the top surface of the power module contacts the heat sink of the peripheral device, thereby ensuring a certain heat dissipation performance of the power module.

[0007] According to some embodiments of the present application, the ceramic substrate adopts a DBC substrate, and the DBC substrate includes a conductive copper layer, a ceramic substrate, and a heat dissipation copper layer stacked in sequence. The anode of the semiconductor diode is electrically connected to one of the switch pins through the conductive copper layer or through a metal flying wire.

[0008] According to some embodiments of the present application, a first pin and a second pin are provided on one side of the power module, the first pin is electrically connected to one end of the thermistor through the conductive copper layer or through a metal flying lead, and the second pin is electrically connected to the other end of the thermistor through the conductive copper layer or the metal flying lead.

[0009] According to some embodiments of the present application, a sixth pin and an eighth pin are further provided on the other side of the power module, the sixth pin is electrically connected to the anode of the semiconductor diode and one of the switch pins through the conductive copper layer or through the metal flying wire, and the eighth pin is electrically connected to the cathode of the semiconductor diode through the conductive copper layer or the metal flying wire.

[0010] According to some embodiments of the present application, a fourth pin and a fifth pin are further provided on one side of the power module, the fourth pin is electrically connected to another switch pin through the conductive copper layer or the metal flying wire, and the fifth pin is electrically connected to the control pin of the power switch tube through the conductive copper layer or the metal flying wire.

[0011] According to some embodiments of the present application, a seventh pin is further provided on the other side of the power module, the seventh pin is electrically connected to another switch pin through the conductive copper layer or the metal flying wire, and the seventh pin is located between the sixth pin and the eighth pin.

[0012] According to some embodiments of the present application, the power switch tube is an IGBT or a MOSFET.

[0013] According to some embodiments of the present application, the semiconductor diode is a silicon-based FRD or a silicon carbide-based diode.

[0014] According to some embodiments of the present application, the sealing layer is made of epoxy resin molding material.

[0015] In a second aspect, an embodiment of the present application provides a conversion device for a photovoltaic inverter, comprising a circuit board, a heat sink and a power module as described in any one of the first aspects above, wherein the power module is mounted on the circuit board by surface mounting or dual in-line packaging, and the heat sink contacts and presses the top of the power module.

[0016] According to the technical solution of the embodiment of the present application, at least the following beneficial effects are achieved: when the conversion device applied to the photovoltaic inverter is actually used, a large number of conversion devices are often required to support the use of the photovoltaic inverter, and a conventional single conversion device includes multiple devices such as a power module, an insulating gasket and a heat sink. In this way, when a large number of conversion devices are installed, not only a large number of power modules need to be installed, but also a large number of insulating gaskets and heat sinks need to be installed. There are many process steps, which makes the installation of the conversion device consume a lot of manpower and material resources; when the power module adopts a ceramic substrate as a circuit substrate, benefiting from the insulation performance of the ceramic substrate, the conversion device is not energized when installed, which can avoid the trouble of installing an additional insulating gasket when the heat sink on the back of the power module is energized, and the ceramic substrate also has a certain heat dissipation performance, which is beneficial to the heat dissipation of the power module; in addition, the power module can be installed on the circuit board by surface mounting or dual in-line packaging. Both installation methods can cancel the insulating gasket. The user can choose the appropriate installation method by himself to enhance the flexibility of the power module.

[0017] According to some embodiments of the present application, thermal grease is applied at the contact point between the heat sink and the power module.

[0018] In a third aspect, an embodiment of the present application provides a photovoltaic inverter, comprising the power module described in any one of the first aspect or the conversion device described in any one of the second aspect.

[0019] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide further understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0021] The present application is further described below with reference to the accompanying drawings and embodiments; Figure 1 is a structural diagram of a power module provided by an embodiment of the present application; Figure 2 is a structural diagram of a power module provided by another embodiment of the present application; Figure 3 is a schematic diagram of the appearance of a power module after packaging provided by another embodiment of the present application; Figure 4 is a circuit diagram of a power module provided by another embodiment of the present application; Figure 5 It is a schematic diagram of a conversion device applied to a photovoltaic inverter provided by an embodiment of the present application.

[0022] Description of the drawings: 100, ceramic substrate; 200, power switch tube; 300, semiconductor diode; 400, thermistor; 500, sealing layer; 110, conductive copper layer; 120, ceramic substrate; 130, heat dissipation copper layer; 600, heat sink; 700, circuit board; 800, power module. DETAILED DESCRIPTION

[0023] This section will describe in detail the specific embodiments of the present application. The preferred embodiments of the present application are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present application, but it cannot be understood as a limitation on the scope of protection of the present application.

[0024] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying 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.

[0025] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features. In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0026] The following is combined with Figure 1-Figure 5 , further elaborating on this application.

[0027] First, as Figure 1 As shown, Figure 1 A power module provided by an embodiment of the present application includes a ceramic substrate 100, a power switch tube 200, a semiconductor diode 300, a thermistor 400 and a sealing layer 500; The power switch tube 200 is disposed on the ceramic substrate 100 and has a plurality of switch pins; The semiconductor diode 300 is disposed on the ceramic substrate 100 , and the anode of the semiconductor diode 300 is electrically connected to a switch pin; The thermistor 400 is disposed on the ceramic substrate 100 and is located between the power switch tube 200 and the semiconductor diode 300; The sealing layer 500 covers the power module.

[0028] In this embodiment, the power module includes a ceramic substrate 100, which is used as a support and is the main structure of the power module. The ceramic substrate 100 includes a ceramic substrate 120 and a metal circuit layer. For electronic packaging, the ceramic substrate 100 plays a key role in connecting the upper and lower parts and connecting the internal and external heat dissipation channels, and also has functions such as electrical interconnection and mechanical support. Ceramics have the advantages of high thermal conductivity, good heat resistance, high mechanical strength, and low thermal expansion coefficient. It is a commonly used substrate material for power semiconductor device packaging. Therefore, the ceramic substrate 100 has insulation performance and conductive performance, wherein the insulation performance refers to the insulation performance between different potential points, and the conductive performance refers to the conductive function of the ceramic substrate 100 as a circuit board. Therefore, using the ceramic substrate 100 as the substrate of the power module can effectively avoid accidental electrical connection between different potential points, thereby preventing electrical short circuit and leakage. In this way, when the power module is installed, there is no need to add an additional insulating gasket outside the power module. In one embodiment, the ceramic substrate 100 may be a conductive material sandwiched between two insulating materials. Specifically, the ceramic substrate 100 may be a DBC (Direct Bond Copper) board or a DPC (Direct Plate Copper) board.

[0029] A power switch tube 200 and a semiconductor diode 300 are arranged on the ceramic substrate 100. The power switch tube 200 and the semiconductor diode 300 are main devices for realizing circuit functions in the power module. For example, when the main function of the power module is power conversion, the power switch tube 200 and the semiconductor diode 300 can be a switch element and a freewheeling element respectively, working together to realize AC-DC, DC-AC conversion or DC-DC conversion, thereby realizing voltage and current regulation; when the main function of the power module is circuit control, the power switch tube 200 and the semiconductor diode 300 can be a high-side switch and a low-side switch respectively, used to adjust the power supply output or control the flow path of energy, etc.; when the main function of the power module is voltage and current When current isolation is performed, the power switch tube 200 and the semiconductor diode 300 can be the light-emitting diode part and the photosensitive element in the optocoupler, respectively, so as to use the optocoupler to isolate the input and output and ensure that there is no direct electrical connection between the two circuits; when the main function of the power module is power amplification, the power switch tube 200 and the semiconductor diode 300 can be the driving transistor and the power transistor, respectively, and the power switch tube 200 is used to drive or control the semiconductor diode 300 to achieve high-efficiency and high-power amplification; specifically, the power switch tube 200 can be an IGBT (insulated gate bipolar transistor) or a MOSFET (metal oxide semiconductor field effect transistor), etc., and the semiconductor diode 300 can be a diode or a thyristor, etc.

[0030] The power switch tube 200 has multiple switch pins, and the anode of the semiconductor diode 300 is electrically connected to a switch pin of the power switch tube 200. In one embodiment, the semiconductor diode 300 and the power switch tube 200 form a function in the power module, and the anode of the semiconductor diode 300 is connected to the drain of the power switch tube 200; in another embodiment, the anode of the semiconductor diode 300 can also be connected to the source of the power switch tube 200. When the anode of the semiconductor diode 300 is connected to different switch pins of the power switch tube 200, the function in the power module can be different. It can be understood that the anode of the semiconductor diode 300 is connected to the drain of the power switch tube 200. When the power switch tube 200 is turned on, the semiconductor diode 300 can provide a low impedance path when the power switch tube 200 is turned on, and the current can pass through the semiconductor diode 300. When the power switch tube 200 is turned off, the semiconductor diode 300 plays a reverse cutoff role to prevent current backflow and protect circuit components from damage. In addition, it can be understood that when the application scenario of the power module is different, the anode of the semiconductor diode 300 is connected to different pins of the power switch tube 200. In addition to the semiconductor diode 300 and the power switch tube 200, the power module may also include more electronic components. In some cases, the anode of the semiconductor diode 300 is connected to the same pin of the power switch tube 200, which can also be used in different application scenarios and play different roles. For example, when the anode of the semiconductor diode 300 is connected to the drain of the power switch tube 200, in the photovoltaic system, the power module is used for battery charging management to ensure that the battery is charged at the optimal voltage and current; in MPPT (Maximum power point In the maximum power point tracking (MPP tracking) control, the maximum power point of the photovoltaic cell can be tracked by adjusting the switch of the power switch tube 200, thereby maximizing the energy output; in the HVAC (Heating, Ventilation and Air Conditioning) system, the power switch tube 200 is used for the switch control of the inverter to adjust the operating speed of the compressor and achieve precise temperature control; in the PFC (Power Factor Correction) circuit, the power switch tube 200 and the semiconductor diode 300 are used to improve the input power factor and reduce the current harmonics to meet the requirements of the grid specification; in the rectifier circuit, the power module enables more efficient energy conversion in the rectification conversion process because the unidirectional conductive characteristics of the diode can reduce energy loss.

[0031] The thermistor 400 is arranged on the ceramic substrate 100 and is located between the power switch tube 200 and the semiconductor diode 300. The thermistor 400 (NTC or PTC type) is used to monitor the temperature of the power switch tube 200 and the semiconductor diode 300. The ceramic substrate 100 has excellent thermal conductivity and electrical insulation, and can quickly conduct the heat generated by the power switch tube 200 and the semiconductor diode 300, and can be detected by the thermistor 400. In this way, the thermistor 400 can quickly and accurately monitor the operating temperature of the power switch tube 200 and the semiconductor diode 300. Because the thermistor 400 is close to the power switch tube 200 and the semiconductor diode 300, it can quickly respond to temperature changes. In different working modes, the heating conditions of the power switch tube 200 and the semiconductor diode 300 may be different. The thermistor 400 is located between the power switch tube 200 and the semiconductor diode 300 to adapt to changes and can effectively monitor the temperature under various conditions. Based on this, the thermistor 400, as a part of the power module, can have different applications. For example, when the temperature of the power switch tube 200 or the semiconductor diode 300 exceeds the safety threshold, the thermistor 400 can trigger the protection circuit, thereby cutting off the power supply or reducing the operating current to prevent the device from being damaged due to overheating; by monitoring the resistance change of the thermistor 400, the temperature distribution of the power module can be understood, and then the size of the heat sink or the speed of the fan can be optimized to improve thermal management; in some applications, the resistance change of the thermistor 400 can be used to compensate for the temperature drift of the power switch tube 200 and the diode. For example, as the temperature increases, the on-state voltage drop of the power switch tube 200 may decrease. The drive current can be adjusted through the signal of the thermistor 400 to maintain the stability of the switching characteristics; the signal of the thermistor 400 can also be input into the microcontroller or the protection circuit. When a temperature abnormality is detected, measures can be taken immediately, such as reducing the operating frequency, limiting the current, or completely shutting down the power supply.

[0032] The sealing layer 500 is used to cover the power module to protect the internal ceramic substrate 100 from the external environment. Furthermore, the sealing layer 500 can also provide electrical insulation to prevent leakage and arcing. The sealing material of the sealing layer 500 can be silicone with good electrical insulation, heat resistance and chemical stability, epoxy resin with good electrical insulation and mechanical strength, and polyurethane with good chemical resistance and flexibility, etc., which can be selected according to actual needs.

[0033] It should be noted that the sealing material of the sealing layer 500 needs to be compatible with the material of the ceramic substrate 100 and will not cause damage to the circuit, and the thermal expansion coefficient of the sealing material of the sealing layer 500 should match the material of the ceramic substrate 100 to prevent stress caused by temperature changes.

[0034] In one embodiment, the power module may only include a power switch tube 200, a semiconductor diode 300, and a thermistor 400. In this way, the structure of the power module is more compact, and the volume and weight are reduced, which is very beneficial for application scenarios with limited space. It can also reduce unnecessary components and reduce manufacturing costs, making the product more competitive in the market. At the same time, since there are fewer components in the module, the thermal management design can be more centralized and simplified, which helps to improve the heat dissipation efficiency. In addition, when the power device in the power module only includes the power switch tube 200 and the semiconductor diode 300, as a power single tube application, a large number of power single tubes need to be used in some scenarios. Therefore, it has a great impact on the reliability of the power single tube. Higher requirements, when the power devices in the power module only include the power switch tube 200 and the semiconductor diode 300, the number of components can be reduced and the potential failure points can be reduced, thereby improving the reliability of the entire power module. In some scenarios, when only a small number of power single tubes are needed, due to the modular design, the power switch tube 200, the semiconductor diode 300 and the thermistor 400 can be replaced as a whole, reducing the replacement cost and simplifying the maintenance process; and, since the power module includes the main basic elements for power conversion and control, namely the power switch tube 200 and the semiconductor diode 300, the power module can be widely used in different power management and motor control scenarios.

[0035] In one embodiment, in addition to the power switch tube 200 and the semiconductor diode 300, the ceramic substrate 100 may also be provided with other electrical components for realizing the function of the power module, for example, circuit protection components such as fuses, sensor components, capacitors, resistors, inductors, and communication interface components, etc. In addition to the power switch tube 200 and the semiconductor diode 300, other components on the ceramic substrate 100 can be conventionally arranged according to actual needs.

[0036] In the power modules provided in some embodiments of the present application, Figure 2 As shown, the ceramic substrate 100 adopts a DBC substrate, which includes a conductive copper layer 110, a ceramic substrate 120, and a heat dissipation copper layer 130 stacked in sequence. The anode of the semiconductor diode 300 and a switch pin of the power switch tube 200 are electrically connected through the conductive copper layer 110 or through a metal flying wire.

[0037] It can be understood that the DBC substrate is a high-performance ceramic substrate 100, in which the copper layer is tightly combined with the ceramic material (which can be aluminum oxide or aluminum nitride) through direct copper coating technology. In this embodiment, the DBC substrate includes a conductive copper layer 110, a ceramic substrate 120, and a heat dissipation copper layer 130 stacked in sequence. The power switch tube 200 and the semiconductor diode 300 are arranged on one side of the conductive copper layer 110. The anode of the semiconductor diode 300 is electrically connected to a switch pin of the power switch tube 200 through the conductive copper layer 110. Since the conductive copper layer 110 has good electrical conductivity, the DBC substrate has high thermal conductivity and good electrical insulation, can effectively conduct the heat generated by the power element and provide good insulation performance, and the DBC substrate has a low thermal resistance, which helps to improve the efficiency and reliability of the power module.

[0038] The semiconductor diode 300 and the power switch tube 200 in the power module need to be connected to the external circuit through pins. When the external circuit is different, the installation position of the semiconductor diode 300 and the power switch tube 200 in the actual power module can be changed to facilitate the connection between the power module and the external circuit. At this time, due to the change of the installation position of the semiconductor diode 300 and the power switch tube 200 in the actual power module, the wiring of the semiconductor diode 300 and the power switch tube 200 to achieve electrical connection through the conductive copper layer 110 may be more complicated or difficult to achieve. Therefore, according to the installation position of the electronic components in the power module, the anode of the semiconductor diode 300 and a switch pin of the power switch tube 200 can also be electrically connected through a metal flying wire.

[0039] In this embodiment, a DBC substrate is used as the ceramic substrate 100 of the power module, so that the ceramic substrate 100 has insulation performance, thereby avoiding the trouble of installing an additional insulating gasket when the heat sink 600 on the back of the power module is charged.

[0040] In the power modules provided in some embodiments of the present application, Figure 3 As shown, Figure 3 It is a schematic diagram of the appearance of the power module after packaging. The numbers in the figure are the pin numbers of the power module. A first pin and a second pin are provided on one side of the power module. The first pin is electrically connected to one end of the thermistor 400 through a conductive copper layer 110 or a metal flying wire, and the second pin is electrically connected to the other end of the thermistor 400 through a conductive copper layer 110 or a metal flying wire.

[0041] It can be understood that the power module, as a power element, needs to be connected to the external circuit through pins. Therefore, a first pin and a second pin are provided on one side of the power module. The first pin is electrically connected to one end of the thermistor 400 through the conductive copper layer 110 or through a metal flying wire, and the second pin is electrically connected to the other end of the thermistor 400 through the conductive copper layer 110 or through a metal flying wire. The first pin and the second pin are pins of the thermistor 400 in the power module for connecting to an external circuit. Through the first pin and the second pin, it can be connected to a measuring circuit in the external circuit, and the resistance change of the thermistor 400 can be converted into an electrical signal, so as to monitor the resistance change of the thermistor 400 in real time, and measure its resistance to infer the temperature of the power module. When the temperature of the power module exceeds a preset safety threshold, the resistance change of the thermistor 400 will cause the current or voltage passing through the first pin and the second pin to change, thereby triggering an external protection circuit, such as shutting down the power switch tube 200 or reducing its operating current to prevent overheating damage.

[0042] In the power modules provided in some embodiments of the present application, Figure 3 As shown, a sixth pin and an eighth pin are also provided on the other side of the power module. The sixth pin is electrically connected to the anode of the semiconductor diode 300 and a switch pin of the power switch tube 200 through the conductive copper layer 110 or through a metal flying wire, and the eighth pin is electrically connected to the cathode of the semiconductor diode 300 through the conductive copper layer 110 or through a metal flying wire.

[0043] It can be understood that the sixth pin is electrically connected to the anode of the semiconductor diode 300 and a switch pin of the power switch tube 200 through the conductive copper layer 110 or through a metal flying wire, and the eighth pin is electrically connected to the cathode of the semiconductor diode 300 through the conductive copper layer 110 or through a metal flying wire. The sixth pin and the eighth pin are respectively connected to the anode and cathode of the semiconductor diode 300, and since the anode of the semiconductor diode 300 is electrically connected to a switch pin of the power switch tube 200, the sixth pin is also connected to a switch pin of the power switch tube 200. Therefore, when the power switch tube 200 is turned on, a conductive path is formed between the sixth pin and the anode of the semiconductor diode 300, allowing current to flow through the load, and the eighth pin can be the common ground point or negative power supply terminal of the power module.

[0044] In the power modules provided in some embodiments of the present application, Figure 3 As shown, a fourth pin and a fifth pin are also provided on one side of the power module. The fourth pin is electrically connected to another switch pin of the power switch tube 200 through the conductive copper layer 110 or through a metal flying wire, and the fifth pin is electrically connected to the control pin of the power switch tube 200 through the conductive copper layer 110 or through a metal flying wire.

[0045] It can be understood that one switch pin of the power switch tube 200 is electrically connected to the fourth pin through the conductive copper layer 110 or through a metal flying wire, another switch pin of the power switch tube 200 is electrically connected to the sixth pin through the conductive copper layer 110 or through a metal flying wire, and the control pin of the power switch tube 200 is electrically connected to the fifth pin through the conductive copper layer 110 or through a metal flying wire. In this way, the power switch tube 200 is connected to the external circuit through the fourth pin, the fifth pin and the sixth pin respectively. The fourth pin can be used as a low-potential connection point of the power switch tube 200, which may be the common ground or negative power supply terminal of the circuit. The fifth pin is used to receive a signal from an external control circuit to control the conduction and cutoff of the power switch tube 200. The sixth pin is also connected to the anode of the semiconductor diode 300, so that the power switch tube 200 and the semiconductor diode 300 can work together in the circuit.

[0046] In the power modules provided in some embodiments of the present application, Figure 3 As shown, a seventh pin is also provided on the other side of the power module. The seventh pin is electrically connected to another switch pin of the power switch tube 200 through the conductive copper layer 110 or through a metal flying wire. The seventh pin is located between the sixth pin and the eighth pin.

[0047] It can be understood that one switch pin of the power module is electrically connected to the sixth pin and the anode of the semiconductor diode 300 through the conductive copper layer 110 or through a metal flying wire, and another switch pin of the power module is electrically connected to the seventh pin through the conductive copper layer 110 or through a metal flying wire. In one embodiment, another switch pin of the power module is also electrically connected to the fourth pin through the conductive copper layer 110 or through a metal flying wire, that is, another switch pin of the power module can be electrically connected to the seventh pin and the fourth pin through the conductive copper layer 110 or through a metal flying wire, the seventh pin can be used as the negative pole of the power input, and the eighth pin can be used as the positive pole of the power input.

[0048] The seventh pin is located between the sixth pin and the eighth pin, that is, in the actual power module, the seventh pin is adjacent to the eighth pin, which is convenient for connecting the positive and negative poles of the external power input, thereby facilitating the wiring when the power module is connected to the external circuit, and the seventh pin is located between the sixth pin and the eighth pin, which helps to achieve better thermal balance on the power module. Since the sixth pin and the eighth pin may be connected to the heating element, the position of the seventh pin can help dissipate heat and reduce thermal gradients. Such a pin layout helps to reduce electromagnetic interference because the current path is shorter and the mutual influence between the pins can be controlled.

[0049] It can be understood that each pin of the power module can be electrically connected to each component in the power module through the conductive copper layer 110 or through the metal flying wire. The conductive copper layer 110 and the metal flying wire provide a flexible connection method, and the circuit can be modified or upgraded without changing the structure of the module itself, so that the circuit layout can be adjusted and optimized according to specific application requirements. The conductive copper layer 110 and the metal flying wire usually have a lower resistance, can effectively transmit large currents, and reduce power losses. For high-power applications, it helps to maintain the efficiency and performance of the module. In addition, the connection between the metal flying wire and the conductive copper layer 110 is more resistant to vibration and shock than traditional welding connections, and therefore has higher reliability in harsh environments, reducing potential failure points caused by poor welding. The use of the conductive copper layer 110 and the metal flying wire can also simplify the manufacturing process, reduce space occupancy, reduce steps in the production process, and achieve a compact module design.

[0050] refer to Figure 4 , Figure 4 is a circuit diagram of a power module provided by another embodiment of the present application, Figure 4 The number in Figure 3 The numbers in correspond to Figure 4 The numbers in the figure are the numbers of the pins connected to the components in the circuit of the power module, and the pin number of the power module, wherein numbers 1 and 2 represent the pins of the thermistor 400 connected to the external circuit, number 4 represents a switch pin of the power switch tube 200 for connecting to the fourth pin, number 5 represents a control pin of the power switch tube 200 for connecting to the fifth pin, number 6 represents an anode pin of the semiconductor diode 300 connected to the fifth pin, number 7 represents another switch pin of the power switch tube 200 for connecting to the seventh pin, number 8 represents a cathode pin of the semiconductor diode 300 for connecting to the eighth pin, T1 represents the power switch tube 200, and D1 represents the semiconductor diode 300.

[0051] In the power module provided in some embodiments of the present application, the power switch tube 200 is an IGBT or a MOSFET.

[0052] In the power module provided in some embodiments of the present application, the semiconductor diode 300 is a silicon-based FRD or a silicon carbide-based diode.

[0053] It is understandable that the power switch tube 200 can be an IGBT or a MOSFET, and the semiconductor diode 300 can be a silicon-based FRD or a silicon carbide-based diode. In this way, the power module can be used in power electronic conversion circuits, motor drive circuits, photovoltaic inverter circuits, and HVAC circuits, etc. IGBT or MOSFET can be used as a switching element to quickly open and close the current to achieve efficient power conversion, and the silicon-based FRD or silicon carbide-based diode is used for rectification or freewheeling to reduce switching losses.

[0054] In the power module provided in some embodiments of the present application, the sealing layer 500 is made of epoxy resin molding material.

[0055] It can be understood that the sealing layer 500 is coated with the ceramic substrate 100 by the sealing material. In the present embodiment, the sealing material used for the sealing layer 500 is an epoxy resin molding material. The epoxy resin has a high thermal decomposition temperature and good thermal stability, as well as good electrical insulation performance. It can withstand high temperatures without deformation or degradation when the power module is working, and remain stable under high voltage and high temperature environments to prevent current leakage. The epoxy resin has good adhesion to a variety of materials (such as ceramics, metals, glass, etc.). When the ceramic substrate 100 of the power module is a DBC substrate, the firmness of the package can be ensured. Therefore, in the present embodiment, the sealing layer 500 is coated with the ceramic substrate 100 by the epoxy resin molding material.

[0056] A second aspect of the present application provides a conversion device applied to a photovoltaic inverter, such as Figure 5 As shown, Figure 5 It is a schematic diagram of a conversion device applied to a photovoltaic inverter provided by an embodiment of the present application, the conversion device includes a circuit board 700, a heat sink 600 and a power module 800 of any one of the above-mentioned first aspects, the power module 800 is installed on the circuit board 700 by surface mounting or dual in-line packaging, and the heat sink 600 contacts the top of the power module 800.

[0057] In this embodiment, the power module 800 can provide two different installation methods, including a surface mount method and a dual in-line package method. The surface mount method and the dual in-line package method are both commonly used installation methods and can meet most installation requirements. Users can choose different power modules 800 according to their own needs.

[0058] It can be understood that in the power module 800 installed in the surface mount method and the dual in-line package method, the components such as the ceramic substrate 100, the sealing layer 500, thermistor 400, the power switch tube 200 and the semiconductor diode 300 are the same, and the difference lies in the packaging method of the power module 800.

[0059] When the power module 800 is installed, for example, when the power module 800 is installed in a circuit as a part of the circuit, the power module 800 can be installed in a surface mount manner, in a dual in-line package manner, or in a TO (Transistor Outline) plug-in manner, etc. The circuit installed in the power module 800 can be a power circuit, a drive circuit, an inverter circuit, a frequency converter circuit, a charging circuit, and a power management circuit, etc.; and the power module 800 tends to generate more heat when it is working, because the power switch tube 200 and the semiconductor diode 300 in the power module 800, such as a transistor, a diode, and an IGBT, will generate a certain amount of power loss during the conduction and switching process, and these losses are mainly manifested in the form of heat, thereby generating more heat. Therefore, when the power module 800 is installed and used, it is usually installed and used together with a heat sink 600, and the heat sink 600 is usually made of a material with good thermal conductivity, which can effectively conduct heat away from the power module 800; However, generally speaking, the semiconductor devices in the power module 800 need to be electrically insulated from the heat sink 600, and the power module 800 generally does not directly contact the heat sink 600 of the external device; but since the substrate layer of the power module 800 in this embodiment is a ceramic substrate 100, the ceramic substrate 100 has provided good insulation performance for the power module 800, and therefore, the power module 800 can directly contact the heat sink 600 of the external device. In this embodiment, the power module 800 has a side on which the power elements are arranged to contact the heat sink 600 of the external device, that is, the heat sink 600 touches the top of the power module 800.

[0060] For example, in one embodiment, the power module 800 is applied to an MPPT circuit and a PFC circuit.

[0061] It can be understood that for photovoltaic and HVAC applications, MPPT circuits and PFC circuits are required for DC-DC conversion or harmonic component control. In photovoltaic and HVAC applications, these functions can be achieved through the power module 800. Further, IGBT or MOSFET, and silicon-based FRD or silicon carbide-based diodes can be used in the power module 800 to achieve these functions. Therefore, in this embodiment, the power module 800 is applied to MPPT and PFC circuits. When the power module 800 is applied to MPPT and PFC circuits, the power switch tube 200 can be an IGBT or MOSFET, and the semiconductor diode 300 can be a silicon-based FRD or a silicon carbide-based diode. Therefore, when the power module 800 is applied to the MPPT circuit and the PFC circuit, the power switch tube 200 of the power module 800 is an IGBT, and the semiconductor diode 300 is a silicon-based FRD, the circuit diagram of the power module 800 can also refer to Figure 4 In the figure, reference numerals 1 and 2 represent pins of thermistor 400 connected to an external circuit, reference numeral 4 represents a source pin of an IGBT, reference numeral 5 represents a gate pin of an IGBT, reference numeral 6 represents a pin for connecting a boost inductor in the circuit, reference numeral 7 represents a pin for connecting a negative electrode of a power supply, reference numeral 8 represents a pin for connecting a positive electrode of a power supply, T1 represents an IGBT, and D1 represents a silicon-based FRD; When the power module 800 is applied to the MPPT circuit and the PFC circuit, the power switch tube 200 is an IGBT, and the semiconductor diode 300 is a silicon-based FRD, the schematic diagram of the packaged appearance of the power module 800 can also be referred to Figure 3 , Figure 3 , numbers 1 and 2 are pins of the thermistor 400, number 3 represents a dummy pin of the power module 800, number 4 represents a source pin of the IGBT, number 5 represents a gate pin of the IGBT, number 6 represents a pin for connecting the MPPT circuit and the boost inductor in the PFC circuit, number 7 represents a pin for connecting the negative pole of the power supply, and number 8 represents a pin for connecting the positive pole of the power supply.

[0062] In the conversion device provided in some embodiments of the present application, thermal grease is applied at the contact point between the heat sink 600 and the power module 800 .

[0063] It is understandable that when the power module 800 is installed in a surface mount manner, in order to improve the heat conduction efficiency between the power module 800 and the heat sink 600, thermal grease can be applied between the power module 800 and the heat sink 600. The thermal grease is a mixture of silicone oil and thermal conductive filler (such as aluminum oxide, aluminum nitride, silicon carbide, etc.), has a high thermal conductivity, and can meet the heat dissipation requirements of the power module 800. The thermal grease also has certain electrical insulation properties, and can provide certain additional electrical insulation properties after removing the insulating gasket between the power module 800 and the heat sink 600.

[0064] A third aspect of the present application provides a photovoltaic inverter, comprising the power module of any one of the first aspect or the conversion device of any one of the second aspect.

[0065] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present application.

Claims

1. A power module, characterized in that: include: Ceramic substrate (100); A power switch tube (200) is arranged on the ceramic substrate (100) and has a plurality of switch pins; A semiconductor diode (300) is disposed on the ceramic substrate (100), wherein an anode of the semiconductor diode (300) is electrically connected to one of the switch pins; A thermistor (400) is disposed on the ceramic substrate (100) and is located between the power switch tube (200) and the semiconductor diode (300); The sealing layer (500) is used for covering the power module.

2. The power module according to claim 1, characterized in that The ceramic substrate (100) is a DBC substrate, comprising a conductive copper layer (110), a ceramic substrate (120), and a heat dissipation copper layer (130) stacked in sequence, and the anode of the semiconductor diode (300) is electrically connected to one of the switch pins through the conductive copper layer (110) or through a metal flying wire.

3. The power module according to claim 2, characterized in that A first pin and a second pin are provided on one side of the power module, the first pin being electrically connected to one end of the thermistor (400) through the conductive copper layer (110) or through a metal flying lead, and the second pin being electrically connected to the other end of the thermistor (400) through the conductive copper layer (110) or through the metal flying lead.

4. The power module according to claim 3, characterized in that A sixth pin and an eighth pin are also provided on the other side of the power module, the sixth pin being electrically connected to the anode of the semiconductor diode (300) and one of the switch pins through the conductive copper layer (110) or through the metal flying lead, and the eighth pin being electrically connected to the cathode of the semiconductor diode (300) through the conductive copper layer (110) or through the metal flying lead.

5. The power module according to claim 4, characterized in that A fourth pin and a fifth pin are also provided on one side of the power module, the fourth pin being electrically connected to another switch pin through the conductive copper layer (110) or the metal flying lead, and the fifth pin being electrically connected to a control pin of the power switch tube (200) through the conductive copper layer (110) or the metal flying lead.

6. The power module according to claim 4, characterized in that A seventh pin is also provided on the other side of the power module. The seventh pin is electrically connected to another switch pin through the conductive copper layer (110) or the metal flying lead. The seventh pin is located between the sixth pin and the eighth pin.

7. The power module according to claim 1, characterized in that The power switch tube (200) is an IGBT or a MOSFET.

8. The power module according to claim 1, characterized in that The semiconductor diode (300) is a silicon-based FRD or a silicon carbide-based diode.

9. The power module according to claim 1, characterized in that The sealing layer (500) is made of epoxy resin molding material.

10. A conversion device applied to a photovoltaic inverter, characterized in that: The invention comprises a circuit board (700), a heat sink (600) and a power module (800) according to any one of claims 1 to 9, wherein the power module (800) is mounted on the circuit board (700) by surface mounting or dual in-line packaging, and the heat sink (600) contacts and presses the top of the power module (800).

11. The conversion device according to claim 10, characterized in that The contact point between the heat sink (600) and the power module (800) is coated with thermal conductive silicone grease.

12. A photovoltaic inverter, characterized in that: A power module comprising any one of claims 1 to 9 or a conversion device comprising any one of claims 10 to 11.

Images