Controller, control circuit board and control method based on patch silicon carbide power tube

Abstract

The invention discloses a controller based on patch silicon carbide power tubes, a control circuit board and a control method. The controller comprises a plurality of patch silicon carbide power tubes, the control circuit board, an insulation pad and a shell. A pin of each patch silicon carbide power tube in the plurality of patch silicon carbide power tubes is welded on the control circuit board by adopting over-reflow soldering, and a welding point arranged on a heat dissipation surface of each patch silicon carbide power tube is welded with the control circuit board; one end of the insulating pad is attached to the bottom in the shell, and the other end of the insulating pad is coated with heat-conducting silicone grease; the control circuit board is arranged in the shell, and the heat dissipation face of each patch silicon carbide power tube abuts against the end, coated with the heat conduction silicone grease, of the insulation pad. The SMD silicon carbide power tube is adopted, so that the installation process of the controller becomes simple, the installation cost is low, and the temperature of the wafer of the SMD silicon carbide power tube can be monitored more accurately.

Description

Technical Field

[0001] The present invention relates to the field of compressor control technology, and in particular to a controller, a control circuit board and a control method based on a surface-mount silicon carbide power tube. Background Art

[0002] At present, the silicon carbide power tube in the air-conditioning compressor controller of new energy vehicles adopts conventional plug-in silicon carbide power tubes. The process of installing conventional plug-in silicon carbide power tubes on the PCB board of the compressor controller is as follows: 1. Apply thermal grease evenly on the bottom shell of the controller; 2. Attach the ceramic substrate and insulation pad to the thermal grease; 3. Apply thermal grease on the ceramic substrate; 4. Bend the pins of the plug-in silicon carbide power tube; 5. Fix the plug-in silicon carbide power tube to the ceramic substrate and the bottom shell with screws; 6. Solder the pins of the plug-in silicon carbide power tube on the PCB board. Therefore, the installation process of conventional plug-in silicon carbide power tubes is complicated and the installation cost is high, and bending the pins of conventional plug-in silicon carbide power tubes will affect the pin stress of the device. In addition, only the pins of the plug-in silicon carbide power tube are soldered on the PCB board. When the PCB board detects the temperature of the plug-in silicon carbide power tube, it can only monitor its pin temperature, but the pin temperature cannot accurately reflect the temperature of its wafer body, which will lead to inaccurate temperature sampling and inaccurate over-temperature protection setting point. Summary of the invention

[0003] The embodiments of the present invention provide a controller, a control circuit board and a control method based on a surface-mount silicon carbide power tube, aiming to solve the problems in the prior art of using conventional plug-in silicon carbide power tubes in compressor controllers, such as complex installation process and high installation cost, bending the pins of the conventional plug-in silicon carbide power tubes will affect the pin stress of the device, and it is difficult to accurately detect the temperature of the conventional plug-in silicon carbide power tube wafer body.

[0004] In the first aspect, an embodiment of the present invention provides a controller based on SMD silicon carbide power tubes, which is applied to a compressor, and comprises: a plurality of SMD silicon carbide power tubes, a control circuit board, an insulating pad and a shell; the pins of each of the plurality of SMD silicon carbide power tubes are soldered to the control circuit board by reflow soldering, and the welding points arranged on the heat dissipation surface of each SMD silicon carbide power tube are welded to the control circuit board; one end of the insulating pad is attached to the bottom inside the shell, and the other end of the insulating pad is coated with thermal grease; the control circuit board is arranged in the shell, and the heat dissipation surface of each SMD silicon carbide power tube is abutted against one end of the insulating pad coated with the thermal grease; wherein the control circuit board is electrically connected to the motor in the compressor through a three-phase connector.

[0005] In a second aspect, an embodiment of the present invention further provides a control circuit board, which is applied to the controller based on the SMD silicon carbide power tube described in the first aspect above, and the control circuit board includes an MCU control chip, a three-phase inverter circuit, a temperature sampling circuit and a current sampling circuit; The pins of several SMD silicon carbide power tubes in the controller based on SMD silicon carbide power tubes are welded on the PCB board corresponding to the three-phase inverter circuit; the temperature sampling resistor in the temperature sampling circuit is located on the PCB board near the heat dissipation surface of any one of the several SMD silicon carbide power tubes, and the current sampling resistor in the current sampling circuit is located on the PCB board near the pins of the several SMD silicon carbide power tubes; The MCU control chip is electrically connected to the three-phase inverter circuit, the temperature sampling circuit and the current sampling circuit; the current sampling circuit is electrically connected to the three-phase inverter circuit; the three-phase inverter circuit is electrically connected to the motor in the compressor through a three-phase connector; The MCU control chip is used to control the plurality of SMD silicon carbide power tubes to convert the high-voltage direct current flowing into the three-phase inverter circuit into three-phase alternating current to drive the motor to work; The MCU control chip is also used to obtain the heat dissipation surface temperature of the plurality of SMD silicon carbide power tubes according to the sampled voltage value output by the temperature sampling circuit, and to obtain the three-phase voltage value corresponding to the three-phase alternating current according to the three-phase current signal sampled by the current sampling circuit; The MCU control chip is also used to control the on and off of the plurality of SMD silicon carbide power tubes according to the heat dissipation surface temperature, the three-phase voltage value and a preset protection strategy.

[0006] In a third aspect, an embodiment of the present invention further provides a control method based on a SMD silicon carbide power tube, which is applied to the MCU control chip on the control circuit board described in the second aspect above, wherein the control circuit board also includes a three-phase inverter circuit, a temperature sampling circuit, and a current sampling circuit, and the control method includes: In response to a start-up instruction, a plurality of SMD silicon carbide power tubes in the three-phase inverter circuit are controlled to convert the high-voltage direct current flowing into the three-phase inverter circuit into three-phase alternating current for driving the motor to work; Obtain the heat dissipation surface temperature of the plurality of SMD silicon carbide power tubes according to the sampled voltage value output by the temperature sampling circuit, and obtain the three-phase voltage value corresponding to the three-phase alternating current according to the three-phase current signal sampled by the current sampling circuit; The on and off of the plurality of SMD silicon carbide power tubes are controlled according to the heat dissipation surface temperature, the three-phase voltage value and a preset protection strategy.

[0007] The embodiment of the present invention provides a controller, a control circuit board and a control method based on a SMD silicon carbide power tube, wherein the controller includes a plurality of SMD silicon carbide power tubes, a control circuit board, an insulating pad and a housing; the pins of each SMD silicon carbide power tube in the plurality of SMD silicon carbide power tubes are soldered to the control circuit board by reflow soldering, and the welding points arranged on the heat dissipation surface of each SMD silicon carbide power tube are soldered to the control circuit board; one end of the insulating pad is attached to the bottom of the housing, and the other end of the insulating pad is coated with thermal conductive silicone grease; the control circuit board is arranged in the housing, and the heat dissipation surface of each SMD silicon carbide power tube is abutted against one end of the insulating pad coated with thermal conductive silicone grease. The present invention adopts SMD silicon carbide power tubes, so that the installation process of the controller becomes simple, the installation cost is low, and the temperature of the SMD silicon carbide power tube wafer can be monitored more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0009] Figure 1 An exploded diagram of a controller based on a SMD silicon carbide power tube provided by an embodiment of the present invention; Figure 2 A front view of a controller based on a SMD silicon carbide power tube provided by an embodiment of the present invention; Figure 3 A schematic diagram of the layout of a controller based on a SMD silicon carbide power tube provided by an embodiment of the present invention; Figure 4 A schematic diagram of the positional relationship of a SMD silicon carbide power tube, a temperature sampling resistor, and a current sampling resistor provided in one embodiment of the present invention; Figure 5 A schematic block diagram of a control circuit board provided in accordance with an embodiment of the present invention; Figure 6 A schematic flow chart of a control method based on a SMD silicon carbide power tube provided in one embodiment of the present invention; in: 1. SMD silicon carbide power tube; 2. Control circuit board; 3. Insulation pad; 4. Shell; 41. Base plate; 411. Mounting cavity; 42. Cover plate; 5. Three-phase connector; 6. High-voltage connector; 7. Input common-mode inductor; 8. Bus capacitor; 9. Low-voltage connector; 10. Transformer; 11. Temperature sampling resistor; 12. Current sampling resistor; 100. MCU control chip; 200. Three-phase inverter circuit; 300. Temperature sampling circuit; 400. Current sampling circuit. DETAILED DESCRIPTION

[0010] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0011] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0012] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0013] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0014] See also Figures 1 to 6 , Figure 1 An exploded diagram of a controller based on a SMD silicon carbide power tube provided by an embodiment of the present invention; Figure 2 A front view of a controller based on a SMD silicon carbide power tube provided by an embodiment of the present invention; Figure 3 A schematic diagram of the layout of a controller based on a SMD silicon carbide power tube provided by an embodiment of the present invention; Figure 4 A schematic diagram of the positional relationship of a SMD silicon carbide power tube, a temperature sampling resistor, and a current sampling resistor provided in one embodiment of the present invention; Figure 5 A schematic block diagram of a control circuit board provided in accordance with an embodiment of the present invention; Figure 6 The following is a flow chart of a control method based on a SMD silicon carbide power tube according to an embodiment of the present invention. Figure 3 It can also be understood as a layout diagram of controller-related devices based on SMD silicon carbide power tubes behind hidden PCB boards and cover plates to reflect the positional relationship of related devices in the controller.

[0015] See also Figures 1 to 3The controller based on SMD silicon carbide power tube provided by the embodiment of the present invention is applied to a compressor, and comprises: a plurality of SMD silicon carbide power tubes 1, a control circuit board 2, an insulating pad 3 and a shell 4; the pins of each SMD silicon carbide power tube 1 in the plurality of SMD silicon carbide power tubes 1 are soldered to the control circuit board 2 by reflow soldering, and the soldering points arranged on the heat dissipation surface of each SMD silicon carbide power tube 1 are soldered to the control circuit board 2; one end of the insulating pad 3 is attached to the bottom of the shell 4, and the other end of the insulating pad 3 is coated with thermal conductive silicone grease; the control circuit board 2 is arranged in the shell 4, and the heat dissipation surface of each SMD silicon carbide power tube 1 is abutted against one end of the insulating pad 3 coated with the thermal conductive silicone grease; wherein the control circuit board 2 is electrically connected to the motor in the compressor through a three-phase connector 5.

[0016] More specifically, the shell 4 includes a base plate 41 and a cover plate 42; the base plate 41 is provided with an installation cavity 411, the insulating pad 3 is located in the installation cavity 411 and is attached to the base plate 41, the control circuit board 2 is located in the installation cavity 411 and is detachably connected to the base plate 41; the cover plate 42 covers the control circuit board 2, and the cover plate 42 is detachably connected to the base plate 41.

[0017] In this embodiment, see Figures 1 to 3 The controller based on the SMD silicon carbide power tube provided in the embodiment of the present invention is mainly used in the compressor of the air conditioner of new energy vehicles, and is composed of a plurality of SMD silicon carbide power tubes 1, a control circuit board 2, an insulating pad 3 and a shell 4. In a specific application process, the installation process of the controller is as follows: first, the pins of each SMD silicon carbide power tube 1 are welded to the corresponding preset pads in the control circuit board 2 by using a reflow soldering process, and the welding points set on the heat dissipation surface of each SMD silicon carbide power tube 1 are welded to the corresponding preset pads in the control circuit board 2; then, the insulating pad 3 is attached to the side of the bottom plate 41 in the shell 4 close to the installation cavity 411, and thermal conductive silicone grease is applied to the side of the insulating pad 3 away from the bottom plate 41; then, the control circuit board 2 with the SMD silicon carbide power tube 1 welded thereon is installed in the installation cavity 411 of the bottom plate 41, and the heat dissipation surface of the SMD silicon carbide power tube 1 welded on the control circuit board 2 is abutted against the insulating pad 3, and the control circuit board 2 is connected to the bottom plate 41 by fasteners; finally, the cover plate 42 is installed on the bottom plate 41 by fasteners, so that the cover plate 42 and the bottom plate 41 enclose the control circuit board 2 in the installation cavity 411. After the controller is fully installed, the control circuit board 2 inside it is electrically connected to the motor in the compressor through the three-phase connector 5, and the motor is driven to work through the control circuit board 2.

[0018] The silicon carbide power tube in the controller provided by the embodiment of the present invention adopts a patch silicon carbide power tube 1, and there is no need to use screw holes and ceramic substrates to fix the silicon carbide power tube, and there is no need to bend the pins of the silicon carbide power tube, which reduces the installation steps of the controller. The installation process of the controller is simple, which greatly improves the production efficiency of the product and has low installation cost. At the same time, the device has no pin stress problem, which improves the reliability of the device and also improves the reliability of the entire controller. The heat dissipation surface of the patch silicon carbide power tube 1 in the controller is in contact with the insulating pad 3, and the heat generated by the patch silicon carbide power tube 1 is conducted to the bottom plate 41 of the housing 4 through the insulating pad 3 for heat dissipation. The body of the patch silicon carbide power tube 1 is close to the bottom plate 41 of the housing 4, and the thermal resistance between the patch silicon carbide and the bottom plate 41 is small, and the heat conduction effect is better, which is conducive to the heat dissipation of the body of the patch silicon carbide power tube 1, and can improve the application power of silicon carbide in actual circuits. In addition, welding points are arranged on the heat dissipation surface of the SMD silicon carbide power tube 1 in the controller. Since the welding points on the heat dissipation surface of the SMD silicon carbide power tube 1 are welded to the control circuit board 2, the control circuit board 2 can monitor the heat dissipation surface temperature of the SMD silicon carbide power tube 1 in real time. The heat dissipation surface temperature of the SMD silicon carbide power tube 1 is closer to its wafer temperature, so the controller can monitor the temperature of the SMD silicon carbide power tube 1 wafer more accurately.

[0019] See also Figures 1 to 5The embodiment of the present invention further provides a control circuit board 2, which is applied to the controller based on the SMD silicon carbide power tube described in any of the above embodiments, and the control circuit board 2 includes an MCU control chip 100, a three-phase inverter circuit 200, a temperature sampling circuit 300 and a current sampling circuit 400; the pins of several SMD silicon carbide power tubes 1 in the controller based on the SMD silicon carbide power tube are soldered on the PCB board corresponding to the three-phase inverter circuit 200; the temperature sampling resistor 11 in the temperature sampling circuit 300 is located on the PCB board near the heat dissipation surface of any one of the several SMD silicon carbide power tubes 1, and the current sampling resistor 12 in the current sampling circuit 400 is located on the PCB board near the pins of the several SMD silicon carbide power tubes 1; the MCU control chip 100 and the three-phase inverter circuit 200, the temperature sampling circuit 300 The MCU control chip 100 is electrically connected to the current sampling circuit 400, and the current sampling circuit 400 is electrically connected to the three-phase inverter circuit 200; the three-phase inverter circuit 200 is electrically connected to the motor in the compressor through a three-phase connector 5; wherein the MCU control chip 100 is used to control the plurality of SMD silicon carbide power tubes 1 to convert the high-voltage direct current flowing into the three-phase inverter circuit 200 into a three-phase alternating current that drives the motor to work; the MCU control chip 100 is also used to obtain the heat dissipation surface temperature of the plurality of SMD silicon carbide power tubes 1 according to the sampled voltage value output by the temperature sampling circuit 300, and obtain the three-phase voltage value corresponding to the three-phase alternating current according to the three-phase current signal sampled by the current sampling circuit 400; the MCU control chip 100 is also used to control the on and off of the plurality of SMD silicon carbide power tubes 1 according to the heat dissipation surface temperature, the three-phase voltage value and a preset protection strategy.

[0020] In this embodiment, the control circuit board 2 includes an MCU control chip 100, a three-phase inverter circuit 200, a temperature sampling circuit 300 and a current sampling circuit 400. Among them, the pins of several SMD silicon carbide power tubes 1 are welded on the PCB board corresponding to the three-phase inverter circuit 200, that is, the pins of several SMD silicon carbide power tubes 1 are welded on the corresponding preset pads in the PCB board, and the electrical connection between several SMD silicon carbide power tubes 1 is realized through the preset circuit on the PCB board, so that several SMD silicon carbide power tubes 1 are electrically connected to form a three-phase inverter circuit 200. The input end of the three-phase inverter circuit 200 is connected to high-voltage direct current, and the on-off of several SMD silicon carbide power tubes 1 is controlled by the MCU control chip 100. Based on the on-off between several SMD silicon carbide power tubes 1, the high-voltage direct current is converted into three-phase alternating current, and the three-phase alternating current is transmitted to the motor in the compressor through the output end of the three-phase inverter circuit 200 and the three-phase connector 5, thereby driving the motor to work.

[0021] Second, see Figure 4 The soldering points set on the heat dissipation surface of the pins of the SMD silicon carbide power tube 1 are soldered to the corresponding preset soldering pads in the corresponding PCB board (see Figure 4 In the A area in the figure), the temperature sampling resistor 11 in the temperature sampling circuit 300 is arranged on the PCB board near the heat dissipation surface of any one of the SMD silicon carbide power tubes 1. The resistance of the temperature sampling resistor 11 changes with the temperature. The temperature sampling circuit 300 is used to output the corresponding sampling voltage value according to the resistance change of the temperature sampling resistor 11, so that the MCU control chip 100 can monitor the heat dissipation surface temperature of the SMD silicon carbide power tubes 1 in real time according to the sampling voltage value output by the temperature sampling circuit 300, and the heat dissipation surface temperature is closer to the wafer temperature of the SMD silicon carbide power tube 1, so that over-temperature protection can be performed more accurately. In addition, the current sampling resistor 12 in the current sampling circuit 400 is arranged on the PCB board near the pin side of the SMD silicon carbide power tubes 1, so that the connection line between the current sampling resistor 12 and the body of the SMD silicon carbide power tube 1 is short, and the current sampling is more anti-interference. Among them, the current sampling circuit 400 includes three current sampling resistors 12, and the three current sampling resistors 12 respectively sample each phase current in the three-phase alternating current output by the three-phase inverter circuit 200. The current sampling circuit 400 is used to filter and amplify the sampling signals of each current sampling resistor 12 to obtain the three-phase current signal in the three-phase alternating current and transmit it to the MCU control chip 100, so that the MCU control chip 100 obtains the three-phase voltage value corresponding to the three-phase alternating current according to the three-phase current signal. The MCU control chip 100 can control the on and off of several SMD silicon carbide power tubes 1 according to the heat dissipation surface temperature, the three-phase voltage value and the preset protection strategy, so as to realize over-temperature and over-current protection for several SMD silicon carbide power tubes 1.

[0022] In one embodiment, see Figure 3 The control circuit board 2 also includes a high-voltage connector 6 and a high-voltage filter circuit; the high-voltage connector 6 is electrically connected to the three-phase inverter circuit 200 through the high-voltage filter circuit.

[0023] Further, see Figure 3 The high-voltage filter circuit includes an input common-mode inductor 7 and a bus capacitor 8; the high-voltage connector 6 is electrically connected to the bus capacitor 8 through the input common-mode inductor 7, and the bus capacitor 8 is electrically connected to the three-phase inverter circuit 200.

[0024] In this embodiment, the high-voltage connector 6 is used to connect high-voltage direct current, and the input common-mode inductor 7 and bus capacitor 8 in the high-voltage filter circuit are both used to filter the high-voltage direct current. The high-voltage filter circuit transmits the filtered high-voltage direct current to the input end of the three-phase inverter circuit 200.

[0025] In one embodiment, see Figure 3 The control circuit board 2 also includes a low-voltage connector 9 and a transformer 10; the low-voltage connector 9 is connected to the transformer 10, and the transformer 10 is electrically connected to the MCU control chip 100, the temperature sampling circuit 300 and the current sampling circuit 400.

[0026] In this embodiment, the low-voltage connector 9 is used to connect to the low-voltage direct current, and the transformer 10 is used to convert the low-voltage direct current into the required working power supply to power the MCU control chip 100, the temperature sampling circuit 300 and the current sampling circuit 400 through the working power supply.

[0027] The control circuit board 2 provided in the embodiment of the present invention can more accurately monitor the wafer temperature of the SMD silicon carbide power tube 1 and the three-phase current signal in the three-phase alternating current output by the three-phase inverter circuit 200 by welding the heat dissipation surface of the pin welding of several SMD silicon carbide power tubes 1 to the PCB board, and by reasonably setting the positions of the temperature sampling resistor 11 in the temperature sampling circuit 300 and the current sampling resistor 12 in the current sampling circuit 400 on the PCB board, so as to achieve better control effect of over-temperature and over-current protection of several SMD silicon carbide power tubes 1.

[0028] See also Figure 6 An embodiment of the present invention further provides a control method based on a SMD silicon carbide power tube, which is applied to the MCU control chip on the control circuit board described in any of the aforementioned embodiments. The control circuit board also includes a three-phase inverter circuit, a temperature sampling circuit and a current sampling circuit. The control method based on the SMD silicon carbide power tube provided by the embodiment of the present invention includes steps S11~S13.

[0029] S11. In response to a start-up instruction, control a plurality of silicon carbide power transistors in the three-phase inverter circuit to convert the high-voltage direct current flowing into the three-phase inverter circuit into three-phase alternating current that drives the motor to work.

[0030] In this embodiment, the MCU control chip responds to the start-up instruction to control the on and off of several SMD silicon carbide power tubes in the three-phase inverter circuit, and converts the high-voltage direct current flowing into the input end of the three-phase inverter circuit into three-phase alternating current based on the on and off between the several SMD silicon carbide power tubes, and transmits the three-phase alternating current to the motor in the compressor through the output end of the three-phase inverter circuit and the three-phase connector, thereby driving the motor to work.

[0031] S12. Obtain the heat dissipation surface temperature of the plurality of SMD silicon carbide power tubes according to the sampled voltage value output by the temperature sampling circuit, and obtain the three-phase voltage value corresponding to the three-phase alternating current according to the three-phase current signal sampled by the current sampling circuit.

[0032] In this embodiment, after the MCU control chip controls the three-phase inverter circuit to output the three-phase alternating current that drives the motor, the MCU control chip receives the sampled voltage value output by the temperature sampling circuit in real time, and obtains the heat dissipation surface temperature of several SMD silicon carbide power tubes according to the sampled voltage value. At the same time, the MCU control chip receives the three-phase current signal in the three-phase alternating current output by the three-phase inverter circuit obtained by sampling the current sampling circuit in real time, and converts the three-phase current signal into the corresponding three-phase voltage value. Among them, the three-phase voltage value includes the U-phase voltage value, the V-phase voltage value and the W-phase voltage value.

[0033] In one embodiment, obtaining the heat dissipation surface temperatures of the plurality of SMD silicon carbide power tubes according to the sampled voltage value output by the temperature sampling circuit includes: Calculating the resistance value of the temperature sampling resistor in the temperature sampling circuit according to the sampling voltage value output by the temperature sampling circuit; The heat dissipation surface temperature is obtained according to the resistance value and a preset temperature curve value table.

[0034] In this embodiment, the temperature sampling resistor in the temperature sampling circuit is arranged on the PCB board near the heat dissipation surface of any one of the several SMD silicon carbide power tubes. The resistance of the temperature sampling resistor changes with the temperature, and the temperature sampling circuit can output the corresponding sampling voltage value according to the change of the resistance of the temperature sampling resistor. The MCU control chip receives the sampling voltage value output by the temperature sampling circuit, and calculates the resistance of the temperature sampling resistor in the temperature sampling circuit according to the sampling voltage value. Then, the resistance value is matched with the preset temperature curve value table to determine the resistance temperature corresponding to the resistance value, and the resistance temperature is the heat dissipation surface temperature of several SMD silicon carbide power tubes. Among them, the temperature curve value can be obtained according to the specification of the temperature sampling resistor.

[0035] S13, controlling the on and off of the plurality of SMD silicon carbide power tubes according to the heat dissipation surface temperature, the three-phase voltage value and a preset protection strategy.

[0036] In this embodiment, the MCU control chip controls the on and off of several SMD silicon carbide power tubes according to the heat dissipation surface temperature, the three-phase voltage value and the preset protection strategy to achieve over-temperature and over-current protection for several SMD silicon carbide power tubes.

[0037] In one embodiment, step S13 includes: If it is determined that the heat dissipation surface temperature is greater than or equal to a preset over-temperature protection value, or if it is determined that any one of the three-phase voltage values ​​is greater than or equal to a preset voltage threshold, the plurality of SMD silicon carbide power tubes are controlled to be disconnected.

[0038] In this embodiment, if the MCU control chip determines that the temperature of the heat dissipation surface is greater than or equal to the preset over-temperature protection value, or determines that any one of the three-phase voltage values ​​(i.e., the U-phase voltage value, the V-phase voltage value, and the W-phase voltage value) is greater than or equal to the preset voltage threshold, the drive of several SMD silicon carbide power tubes is stopped, that is, each of the several SMD silicon carbide power tubes is switched to the disconnected state, so that the motor stops working, and the shutdown protection is realized, and the over-temperature and over-current protection of several SMD silicon carbide power tubes is realized. Among them, the over-temperature protection value and the voltage threshold can be set according to the specification of the SMD silicon carbide power tube.

[0039] In one embodiment, after the method of controlling the plurality of SMD silicon carbide power tubes to disconnect if it is determined that the heat dissipation surface temperature is greater than or equal to a preset over-temperature protection value, or if it is determined that any one of the three-phase voltage values ​​is greater than or equal to a preset voltage threshold, further comprises: Get the current heat dissipation surface temperature and the current three-phase voltage value; If it is determined that the current heat dissipation surface temperature is lower than the over-temperature protection value, and it is determined that each phase voltage value in the current three-phase voltage value is lower than the voltage threshold, then the process returns to the step of controlling several SMD silicon carbide power tubes in the three-phase inverter circuit to convert the high-voltage direct current flowing into the three-phase inverter circuit into three-phase alternating current to drive the motor.

[0040] In this embodiment, after over-temperature or over-current protection, the MCU control chip obtains the current heat dissipation surface temperature and the current three-phase voltage value in real time. The current heat dissipation surface temperature represents the heat dissipation surface temperature of several SMD silicon carbide power tubes at the current moment, and the current three-phase voltage value represents the three-phase voltage value corresponding to the three-phase alternating current at the current moment. Among them, the step of obtaining the current heat dissipation surface temperature and the current three-phase voltage value is similar to step S12, and will not be repeated here. If the MCU control chip determines that the current heat dissipation surface temperature is less than the over-temperature protection value, and determines that each phase voltage value in the current three-phase voltage value is less than the voltage threshold, it means that the heat dissipation surface temperature of several SMD silicon carbide power tubes is within the safe temperature range, and the current of each phase of the three-phase alternating current is within the safe current range, the MCU control chip resumes the drive of several SMD silicon carbide power tubes, so that the three-phase inverter circuit re-outputs three-phase alternating current, and the motor resumes normal operation.

[0041] The present invention discloses a control method based on a SMD silicon carbide power tube, which is applied to the MCU control chip on the control circuit board described in any of the aforementioned embodiments, and can more accurately monitor the wafer temperature of the SMD silicon carbide power tube and the three-phase current signal in the three-phase alternating current output by the three-phase inverter circuit, thereby achieving better control effect on over-temperature and over-current protection of several SMD silicon carbide power tubes.

[0042] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A controller based on SMD silicon carbide power tube, applied to compressor, characterized in that: include: Several SMD silicon carbide power tubes, control circuit boards, insulation pads and housings; The pins of each of the several SMD silicon carbide power tubes are soldered to the control circuit board by reflow soldering, and the welding points arranged on the heat dissipation surface of each SMD silicon carbide power tube are welded to the control circuit board; one end of the insulating pad is attached to the bottom inside the shell, and the other end of the insulating pad is coated with thermal grease; the control circuit board is arranged in the shell, and the heat dissipation surface of each SMD silicon carbide power tube is abutted against one end of the insulating pad coated with the thermal grease; wherein the control circuit board is electrically connected to the motor in the compressor through a three-phase connector.

2. The controller based on SMD silicon carbide power tube according to claim 1, characterized in that: The housing comprises a bottom plate and a cover plate; the bottom plate is provided with a mounting cavity, the insulating pad is located in the mounting cavity and attached to the bottom plate, and the control circuit board is located in the mounting cavity and is detachably connected to the bottom plate; The cover plate covers the control circuit board, and the cover plate is detachably connected to the bottom plate.

3. A control circuit board, applied to a controller based on a SMD silicon carbide power tube as described in any one of claims 1-2, characterized in that: The control circuit board includes an MCU control chip, a three-phase inverter circuit, a temperature sampling circuit and a current sampling circuit; The pins of several SMD silicon carbide power tubes in the controller based on SMD silicon carbide power tubes are welded on the PCB board corresponding to the three-phase inverter circuit; the temperature sampling resistor in the temperature sampling circuit is located on the PCB board near the heat dissipation surface of any one of the several SMD silicon carbide power tubes, and the current sampling resistor in the current sampling circuit is located on the PCB board near the pins of the several SMD silicon carbide power tubes; The MCU control chip is electrically connected to the three-phase inverter circuit, the temperature sampling circuit and the current sampling circuit; the current sampling circuit is electrically connected to the three-phase inverter circuit; the three-phase inverter circuit is electrically connected to the motor in the compressor through a three-phase connector; The MCU control chip is used to control the plurality of SMD silicon carbide power tubes to convert the high-voltage direct current flowing into the three-phase inverter circuit into three-phase alternating current to drive the motor to work; The MCU control chip is also used to obtain the heat dissipation surface temperature of the plurality of SMD silicon carbide power tubes according to the sampled voltage value output by the temperature sampling circuit, and to obtain the three-phase voltage value corresponding to the three-phase alternating current according to the three-phase current signal sampled by the current sampling circuit; The MCU control chip is also used to control the on and off of the plurality of SMD silicon carbide power tubes according to the heat dissipation surface temperature, the three-phase voltage value and a preset protection strategy.

4. The control circuit board according to claim 3, characterized in that: It also includes a high-voltage connector and a high-voltage filter circuit; the high-voltage connector is electrically connected to the three-phase inverter circuit through the high-voltage filter circuit.

5. The control circuit board according to claim 4, characterized in that: The high-voltage filter circuit includes an input common-mode inductor and a bus capacitor; the high-voltage connector is electrically connected to the bus capacitor via the input common-mode inductor, and the bus capacitor is electrically connected to the three-phase inverter circuit.

6. The control circuit board according to claim 3, characterized in that: It also includes a low-voltage connector and a transformer; the low-voltage connector is connected to the transformer, and the transformer is electrically connected to the MCU control chip, the temperature sampling circuit and the current sampling circuit.

7. A control method based on a SMD silicon carbide power tube, applied to an MCU control chip on a control circuit board as described in any one of claims 3-6, wherein the control circuit board also includes a three-phase inverter circuit, a temperature sampling circuit and a current sampling circuit, characterized in that: include: In response to a start-up instruction, a plurality of SMD silicon carbide power tubes in the three-phase inverter circuit are controlled to convert the high-voltage direct current flowing into the three-phase inverter circuit into three-phase alternating current for driving the motor to work; Obtain the heat dissipation surface temperature of the plurality of SMD silicon carbide power tubes according to the sampled voltage value output by the temperature sampling circuit, and obtain the three-phase voltage value corresponding to the three-phase alternating current according to the three-phase current signal sampled by the current sampling circuit; The on and off of the plurality of SMD silicon carbide power tubes are controlled according to the heat dissipation surface temperature, the three-phase voltage value and a preset protection strategy.

8. The control method based on SMD silicon carbide power tube according to claim 7, characterized in that: The step of obtaining the heat dissipation surface temperatures of the plurality of SMD silicon carbide power tubes according to the sampled voltage value output by the temperature sampling circuit comprises: Calculating the resistance value of the temperature sampling resistor in the temperature sampling circuit according to the sampling voltage value output by the temperature sampling circuit; The heat dissipation surface temperature is obtained according to the resistance value and a preset temperature curve value table.

9. The control method based on SMD silicon carbide power tube according to claim 7, characterized in that: The controlling the on and off of the plurality of SMD silicon carbide power tubes according to the heat dissipation surface temperature, the three-phase voltage value and a preset protection strategy includes: If it is determined that the heat dissipation surface temperature is greater than or equal to a preset over-temperature protection value, or if it is determined that any one of the three-phase voltage values ​​is greater than or equal to a preset voltage threshold, the plurality of SMD silicon carbide power tubes are controlled to be disconnected.

10. The control method based on SMD silicon carbide power tube according to claim 9, characterized in that: After the method of controlling the plurality of SMD silicon carbide power tubes to disconnect if it is determined that the heat dissipation surface temperature is greater than or equal to a preset over-temperature protection value, or if it is determined that any one of the three-phase voltage values ​​is greater than or equal to a preset voltage threshold, further includes: Get the current heat dissipation surface temperature and the current three-phase voltage value; If it is determined that the current heat dissipation surface temperature is lower than the over-temperature protection value, and it is determined that each phase voltage value in the current three-phase voltage value is lower than the voltage threshold, then the process returns to the step of controlling several SMD silicon carbide power tubes in the three-phase inverter circuit to convert the high-voltage direct current flowing into the three-phase inverter circuit into three-phase alternating current to drive the motor.

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