IGBT Module for Wind Power Inverter with Heat Dissipation System and Its Fault Diagnosis Method

Abstract

The present invention discloses an IGBT module for a wind power frequency converter with a heat dissipation system and a fault diagnosis method thereof, relating to the field of IGBT modules for wind power frequency converters. The heat dissipation system of the IGBT module for the wind power frequency converter includes a thermoelectric refrigeration component and a radiator. The thermoelectric refrigeration component includes an electrically insulating thermal conductive adhesive, a connecting plate, a P-type semiconductor, an N-type semiconductor and a lower connecting plate; the electrically insulating thermal conductive adhesive is applied to the bottom surface of the copper substrate, the connecting plates are fixedly arranged in an orderly manner on the electrically insulating thermal conductive adhesive, the bottom of the connecting plate is provided with a P-type semiconductor and an N-type semiconductor, and they are connected in series through the lower connecting plate and a temperature control switch and connected to a DC power supply; the radiator includes a heat dissipation channel and a blower, and the blower dissipates heat from the bottom surface of the embedded lower connecting plate. Its fault diagnosis system includes an adjustable regulated power supply, a 24V DC power supply, an adjustable PWM module, an oscilloscope and an infrared temperature display. The present invention improves the heat dissipation efficiency, reduces the failure rate; can quickly and accurately locate faults; and also saves the maintenance cost.

Description

Technical Field

[0001] The present invention relates to the field of IGBT modules for wind power inverters, and particularly to an IGBT module for wind power inverters with a heat dissipation system and a fault diagnosis method therefor. Background Technique

[0002] A wind power generation system is a device that converts wind energy into mechanical energy and then converts the mechanical energy into electrical energy. In this system, one end of the inverter is connected to the power grid, and the other end is connected to the rotor of the doubly-fed generator. The excitation control of the doubly-fed generator is achieved through the inverter. An inverter is a power control device that converts the power frequency power supply into electrical energy of another frequency by the on-off action of power semiconductor devices. Since the inverter can dynamically adjust the amplitude, frequency, and phase of the current on the rotor side of the doubly-fed generator according to the change of the speed, the wind power generation system can output stable electrical energy to the power grid.

[0003] During strong winds, due to the dual reasons of the fan usage rate and the temperature, the inverter fails frequently, and the damage of the IGBT in the inverter shows an increasing trend. For example, a fan consists of 7 IGBT modules. Since the specific damaged parts of the IGBT in the fan inverter cannot be determined, the damage of the IGBT is often judged by its appearance. At the same time, the IGBT is expensive. Replacing a large number of IGBTs directly causes a great increase in the operation and maintenance costs in terms of equipment procurement, logistics, and installation. Therefore, it is necessary to improve the existing IGBT module in combination with the actual operating conditions of the wind power inverter and the special driving and modulation principles to meet the heat dissipation requirements of the on-site actual IGBT, and at the same time, the IGBT can be diagnosed for faults in a timely manner. Summary of the Invention

[0004] In order to solve the problems of low heat dissipation efficiency of the IGBT module for wind power inverters and the lack of a fault diagnosis method, the present invention provides an IGBT module for wind power inverters with a heat dissipation system and a fault diagnosis method therefor.

[0005] The present invention is realized by the following technical solutions: An IGBT module for a wind power frequency converter with a heat dissipation system, including an IGBT module, the IGBT module is composed of a chip, a welding layer, a DBC substrate, a welding layer and a copper substrate from top to bottom in sequence; further including a heat dissipation system, the heat dissipation system includes a thermoelectric refrigeration component and a radiator, the thermoelectric refrigeration component includes an electrically insulating thermal conductive adhesive, a connecting plate, a P-type semiconductor, an N-type semiconductor and a lower connecting plate; the electrically insulating thermal conductive adhesive is applied to the bottom surface of the copper substrate, a plurality of connecting plates are provided and are fixedly arranged on the electrically insulating thermal conductive adhesive in an orderly manner, a pair of P-type semiconductor and N-type semiconductor are fixedly connected to the bottom of each connecting plate, and are arranged with the P-type semiconductor on the left side and the N-type semiconductor on the right side, the bottoms of the N-type semiconductor on each connecting plate and the P-type semiconductor on the adjacent connecting plate are connected into one body through the same corresponding lower connecting plate, the bottom of the P-type semiconductor of the connecting plate on the left edge is connected to the lower connecting plate on this side edge, the bottom of the N-type semiconductor of the connecting plate on the right edge is connected to the lower connecting plate on this side edge, the lower connecting plate on the left edge is connected to the negative electrode of the DC power supply, and the lower connecting plate on the right edge is connected in series with the temperature control switch to the positive electrode of the DC power supply; the radiator includes a heat dissipation channel and a fan, two fans are provided and are respectively located at both ends of the heat dissipation channel, the temperature control switch is located inside the heat dissipation channel, and the lower bottom surface of the lower connecting plate is embedded in the heat dissipation channel.

[0006] An IGBT module for a wind power frequency converter with a heat dissipation system designed by the present invention adds a heat dissipation system to the IGBT module, and this heat dissipation system is a rapid heat dissipation system. The IGBT module is composed of a chip, a welding layer, a DBC liner, a welding layer, and a copper substrate from top to bottom in sequence (this is a conventional structure and will not be elaborated in detail). The heat dissipation system includes a thermoelectric refrigeration component and a radiator, and the two work together to achieve rapid heat dissipation of the IGBT. The thermoelectric refrigeration component includes an electrically insulating thermal conductive adhesive, a connecting plate, a P-type semiconductor, an N-type semiconductor, and a lower connecting plate. The electrically insulating thermal conductive adhesive is applied to the bottom surface of the copper substrate, which plays a good heat conduction role and also has electrical insulation characteristics. There are multiple connecting plates, which are arranged and fixed on the electrically insulating thermal conductive adhesive in an orderly manner, so that the IGBT module can be fully contacted with the connecting plates, reducing the contact thermal resistance between the IGBT module and the connecting plates. A pair of P-type semiconductors and N-type semiconductors are fixedly connected to the bottom of each connecting plate. The main purpose is to utilize the thermoelectric refrigeration principle to connect the P-type semiconductors and N-type semiconductors under multiple connecting plates in series to form a cold end and a hot end, and refrigeration can be carried out through different temperature differences between the upper and lower parts. For the P-type semiconductors and N-type semiconductors under each connecting plate, the P-type semiconductor is on the left side and the N-type semiconductor is on the right side. The implementation method of the series connection is as follows: The N-type semiconductor on each connecting plate and the bottom of the P-type semiconductor of the adjacent connecting plate are connected as a whole through the same corresponding lower connecting plate. The bottom of the P-type semiconductor of the connecting plate on the left edge is connected to the lower connecting plate on this side edge, and the bottom of the N-type semiconductor of the connecting plate on the right edge is connected to the lower connecting plate on this side edge. The lower connecting plate on the left edge is connected to the negative pole of the DC power supply, and the lower connecting plate on the right edge is connected in series with the temperature control switch to the positive pole of the DC power supply. In this way, a series circuit is formed. When a certain value of DC voltage is output from the DC power supply and applied to both ends of the P-type semiconductor and the N-type semiconductor, the connecting plate becomes the cold end, and refrigeration is carried out through different temperature differences between the upper and lower parts to reduce the temperature of the IGBT module, and the lower connecting plate becomes the hot end. The radiator includes a heat dissipation channel and a fan. There are two fans, which are respectively located at both ends of the heat dissipation channel, so that air is inhaled from one end and sent out from the other end. The lower bottom surface of the lower connecting plate is embedded in the heat dissipation channel, so that the heat on the lower connecting plate can be discharged in time. The temperature control switch is located inside the heat dissipation channel. The temperature control switch can monitor the air temperature in the heat dissipation channel and control whether to apply voltage to both ends of the semiconductor according to the monitored air temperature.The heat dissipation process of the IGBT module for wind power frequency converters in the present invention is as follows: When the IGBT module operates at a high frequency, a large amount of heat is generated inside it. The heat of the IGBT module is transferred to the connection plate through the electrically insulating thermal conductive adhesive with strong thermal conductivity, and the temperature of the connection plate immediately rises. When the temperature control switch detects that the temperature is higher than the set value, the temperature control switch closes, so that the DC voltage of 8 - 14V output by the DC power supply is applied to both ends of the N-type semiconductor and the P-type semiconductor. The connection plate becomes the cold end, and refrigeration is carried out through the difference in temperature between the upper and lower parts, so as to reduce the temperature of the IGBT module. The lower connection plate becomes the hot end, and its heat is air-cooled by the fan, and the heat is dissipated from the heat dissipation channel in time.

[0007] Preferably, the electrically insulating thermal conductive adhesive is a thermally conductive silica gel with good insulation and thermal conductivity.

[0008] Preferably, the connection plate and the lower connection plate are made of metal plates with good thermal conductivity.

[0009] Since the replacement cost of the IGBT module for wind power frequency converters is high, during the working process, it is also necessary to diagnose the faults of the IGBT module in time. The fault diagnosis method is implemented in the following diagnosis system, and the IGBT module is diagnosed. The diagnosis system includes an adjustable regulated power supply, a 24V DC power supply, an adjustable PWM module, an oscilloscope, and an infrared temperature display. The input end of the adjustable regulated power supply is connected to 220V alternating current, and the output end provides 60V DC power for rectification for the IGBT module. The input end of the 24V DC power supply is connected to 220V alternating current, and the output end provides 24V DC power for the IGBT module drive circuit and the adjustable PWM module. The oscilloscope is used to record the gate drive voltage waveform of the IGBT module, the output AC signal waveform of the IGBT module, and the collector feedback signal waveform. The infrared temperature display is used to record the real-time temperature when the IGBT module is running. The fault diagnosis method includes the following steps:

[0010] 1) The output end of the 24V DC power supply provides 24V DC power for the IGBT module drive circuit and the adjustable PWM module, so that they can work normally;

[0011] 2) The adjustable PWM module generates pulse signals with adjustable frequency and amplitude to provide on or off pulse signals for the IGBT module drive circuit, so as to control the IGBT module to work according to the given signal and output the specified inverter waveform;

[0012] 3) The output end of the adjustable regulated power supply is connected to the positive and negative main terminals of the IGBT module to provide 60V DC power for rectification;

[0013] 4) Under normal power supply conditions, the IGBT module is driven by an adjustable PWM module. When it works normally, the IGBT module will output an AC signal waveform corresponding to the input signal waveform; if the IGBT module is abnormal, it will not output an AC signal waveform or the output AC signal waveform will deviate greatly.

[0014] 5) Based on the gate drive voltage waveform, the output AC signal waveform, and the collector feedback signal waveform of the IGBT module collected on the oscilloscope, it is possible to determine whether the IGBT module is faulty and the location of the fault point, so as to carry out corresponding maintenance.

[0015] 6) Since the IGBT module operates at a high frequency state, its switching damage and power damage are large, and a large amount of heat will be generated inside. The infrared temperature display can record the temperature of the IGBT module during operation in real time, so as to detect whether its heat dissipation performance is good.

[0016] Compared with the prior art, the present invention has the following beneficial effects: An IGBT module for a wind power frequency converter with a heat dissipation system and its fault diagnosis method provided by the present invention: ①Improve the heat dissipation efficiency and reduce the failure rate. Since the high temperature generated during the operation of the IGBT module is the biggest reason for the damage of the IGBT module, by using this heat dissipation system (using the principle of thermoelectric refrigeration), when the heat dissipation system works, the copper substrate of the IGBT module is in direct contact with the cold end (connection plate), and the hot end (lower connection plate) is located inside the radiator, so that the temperature of the IGBT module is significantly reduced, and the heat can be effectively and quickly dissipated, improving the operation reliability of the IGBT module; ②Can quickly and accurately locate faults: The specific damage location inside the IGBT module can be intuitively judged by the waveforms of the drive signal, the collector feedback signal, and the output AC signal, accurately locate the fault point, and greatly reduce the fault handling time; ③Save maintenance costs: In the past, there was no professional equipment for detecting IGBTs in wind farms, and the damage of IGBTs was often judged by appearance, and the specific damage location could not be determined. By using this test method, the damage degree of the IGBT can be judged, and the IGBT with fewer damaged components can be maintained independently, which can not only meet the urgent need for spare parts on site, but also save part of the maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of the heat dissipation system of the IGBT module.

[0018] Figure 2 It is a schematic structural diagram of the fault diagnosis system of the IGBT module.

[0019] The markings in the figure are as follows: 1 - adjustable regulated power supply, 2 - 24V DC power supply, 3 - adjustable PWM module, 4 - IGBT module, 5 - oscilloscope, 6 - infrared temperature display, 7 - DC power supply, 8 - lower connecting plate, 9 - P-type semiconductor, 10 - connecting plate, 11 - N-type semiconductor, 12 - temperature control switch, 13 - electrically insulating thermal conductive adhesive, 14 - fan, 15 - heat dissipation channel. Specific embodiments

[0020] The present invention will be further described below in conjunction with specific embodiments.

[0021] An IGBT module for a wind power frequency converter with a heat dissipation system includes an IGBT module 4, and the IGBT module 4 is composed of a chip, a welding layer, a DBC substrate, a welding layer, and a copper substrate from top to bottom in sequence, as Figure 1 shown: including a heat dissipation system, the heat dissipation system includes a thermoelectric refrigeration component and a radiator, and the thermoelectric refrigeration component includes an electrically insulating thermal conductive adhesive 13, a connecting plate 10, a P-type semiconductor 9, an N-type semiconductor 11, and a lower connecting plate 8; the electrically insulating thermal conductive adhesive 13 is applied to the bottom surface of the copper substrate, there are multiple connecting plates 10, and they are fixedly arranged in an orderly manner on the electrically insulating thermal conductive adhesive 13. A pair of P-type semiconductor 9 and N-type semiconductor 11 are fixedly connected to the bottom of each connecting plate 10, and they are arranged with the P-type semiconductor 9 on the left side and the N-type semiconductor 11 on the right side. The bottoms of the N-type semiconductor 11 on each connecting plate 10 and the P-type semiconductor 9 of the adjacent connecting plate 10 are connected as a whole through the same corresponding lower connecting plate 8. The bottom of the P-type semiconductor 9 of the connecting plate 10 on the left edge is connected to the lower connecting plate 8 on this side edge, and the bottom of the N-type semiconductor 11 of the connecting plate 10 on the right edge is connected to the lower connecting plate 8 on this side edge. The lower connecting plate 8 on the left edge is connected to the negative pole of the DC power supply 7, and the lower connecting plate 8 on the right edge is connected in series with the temperature control switch 12 to the positive pole of the DC power supply 7; the radiator includes a heat dissipation channel 15 and a fan 14. There are two fans 14, which are respectively located at both ends of the heat dissipation channel 15. The temperature control switch 12 is located inside the heat dissipation channel 15, and the lower bottom surface of the lower connecting plate 8 is embedded in the heat dissipation channel 15.

[0022] In this embodiment: the electrically insulating thermal conductive adhesive 13 is a thermally conductive silica gel with good insulation and thermal conductivity; the connecting plate 10 and the lower connecting plate 8 are made of metal plates with good thermal conductivity, and the model of the IGBT module 4 is: FS450R17KE3 / AGDR-71C S.

[0023] The heat dissipation process of the IGBT module for the wind power frequency converter in this embodiment is as follows: When the IGBT module 4 operates in a high-frequency state, a large amount of heat is generated inside it. The heat of the IGBT module 4 is transferred to the connecting plate 10 through the electrically insulating thermal conductive adhesive 13 with strong thermal conductivity, and the temperature of the connecting plate 10 immediately rises. When the temperature control switch 12 detects that the temperature is higher than the set value, the temperature control switch 12 closes, so that the DC voltage of 8 - 14V output by the DC power supply 7 is applied to both ends of the N-type semiconductor 11 and the P-type semiconductor 9. The connecting plate 10 becomes the cold end, and refrigeration is carried out through the difference in upper and lower temperature differences, so that the temperature of the IGBT module 4 is reduced. The lower connecting plate 8 becomes the hot end, and its heat is air-cooled by the blower 14, and the heat is dissipated from the heat dissipation channel 15 in time.

[0024] The fault diagnosis method of the above embodiment is implemented in the following diagnosis system, and the IGBT module 4 is diagnosed. The diagnosis system includes an adjustable regulated power supply 1, a 24V DC power supply 2, an adjustable PWM module 3, an oscilloscope 5 and an infrared temperature display 6. The input end of the adjustable regulated power supply 1 is connected to 220V alternating current, and the output end provides 60V direct current for rectification for the IGBT module 4. The input end of the 24V DC power supply 2 is connected to 220V alternating current, and the output end provides 24V direct current for the IGBT module drive circuit 4 and the adjustable PWM module 3. The oscilloscope 5 is used to record the gate drive voltage waveform of the IGBT module 4, the output AC signal waveform of the IGBT module 4 and the collector feedback signal waveform. The infrared temperature display 6 is used to record the real-time temperature when the IGBT module 4 is running. The fault diagnosis method includes the following steps:

[0025] 1) The output end of the 24V DC power supply 2 provides 24V direct current for the IGBT module drive circuit 4 and the adjustable PWM module 3, so that they can work normally;

[0026] 2) The adjustable PWM module 3 generates a pulse signal with adjustable frequency and amplitude to provide an on or off pulse signal for the IGBT module 4 drive circuit, so as to control the IGBT module 4 to work according to the given signal and output a specified inverter waveform;

[0027] 3) The output end of the adjustable regulated power supply 1 is connected to the positive and negative main terminals of the IGBT module 4 to provide 60V direct current for rectification;

[0028] 4) When the IGBT module 4 is under normal power supply and is driven by the adjustable PWM module 3, when it works normally, the IGBT module 4 will output an AC signal waveform corresponding to the input signal waveform. If the IGBT module 4 is abnormal, it will not output an AC signal waveform or the output AC signal waveform deviates greatly;

[0029] 5) Based on the gate drive voltage waveform, the output AC signal waveform, and the collector feedback signal waveform of the IGBT module 4 collected on the oscilloscope 5, it is possible to determine whether the IGBT module 4 is faulty and the location of the fault point, so as to carry out corresponding maintenance;

[0030] 6) Since the IGBT module 4 operates at a high frequency state, its switching damage and power damage are large, and a large amount of heat will be generated inside. The infrared temperature display 6 can record the temperature of the IGBT module 4 during operation in real time, so as to detect whether its heat dissipation performance is good.

[0031] The scope of protection required by the present invention is not limited to the above specific embodiments. Moreover, for those skilled in the art, the present invention can have various deformations and changes. Any modifications, improvements, and equivalent replacements made within the concept and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A fault diagnosis method for an IGBT module used in a wind power frequency converter with a heat dissipation system, characterized in that: The described fault diagnosis method is implemented in the following diagnosis system and diagnoses the IGBT module (4). The diagnosis system includes an adjustable regulated power supply (1), a 24V DC power supply (2), an adjustable PWM module (3), an oscilloscope (5) and an infrared temperature display (6). The input end of the adjustable regulated power supply (1) is connected to 220V AC, and the output end provides 60V DC for rectification to the IGBT module (4). The input end of the 24V DC power supply (2) is connected to 220V AC, and the output end provides 24V DC for the drive circuit of the IGBT module (4) and the adjustable PWM module (3). The oscilloscope (5) is used to record the gate drive voltage waveform of the IGBT module (4), the output AC signal waveform of the IGBT module (4) and the collector feedback signal waveform. The infrared temperature display (6) is used to record the real-time temperature when the IGBT module (4) is running. The fault diagnosis method includes the following steps: 1) The output end of the 24V DC power supply (2) provides 24V DC for the drive circuit of the IGBT module (4) and the adjustable PWM module (3) to enable them to work normally; 2) The adjustable PWM module (3) generates pulse signals with adjustable frequency and amplitude to provide on or off pulse signals for the drive circuit of the IGBT module (4), so as to control the IGBT module (4) to work according to the given signal and output the specified inverter waveform; 3) The output end of the adjustable regulated power supply (1) is connected to the positive and negative main terminals of the IGBT module (4) to provide 60V DC for rectification; 4) When the power supply of the IGBT module (4) is normal and it is driven by the adjustable PWM module (3), when the IGBT module (4) works normally, it will output an AC signal waveform corresponding to the input signal waveform; if the IGBT module (4) is abnormal, it will not output an AC signal waveform or the output AC signal waveform has a large deviation; 5) According to the gate drive voltage waveform of the IGBT module (4), the output AC signal waveform of the IGBT module (4) and the collector feedback signal waveform collected on the oscilloscope (5), it can be judged whether the IGBT module (4) is faulty and the location of the fault point, so as to carry out corresponding maintenance; 6) Since the IGBT module (4) works in a high-frequency state, its switch damage and power damage are large, and a large amount of heat will be generated inside it. The infrared temperature display (6) can record the temperature when the IGBT module (4) is running in real time, so as to detect whether its heat dissipation performance is good; Among them, the IGBT module (4) is composed of a chip, a welding layer, a DBC liner, a welding layer and a copper substrate from top to bottom in sequence, and further includes a heat dissipation system. The heat dissipation system includes a thermoelectric refrigeration component and a radiator. The thermoelectric refrigeration component includes an electrically insulating thermal conductive adhesive (13), a connecting plate (10), a P-type semiconductor (9), an N-type semiconductor (11) and a lower connecting plate (8); the electrically insulating thermal conductive adhesive (13) is applied on the bottom surface of the copper substrate, multiple connecting plates (10) are provided and are fixedly arranged on the electrically insulating thermal conductive adhesive (13) in an orderly manner. A pair of P-type semiconductor (9) and N-type semiconductor (11) are fixedly connected to the bottom of each connecting plate (10), and are arranged with the P-type semiconductor (9) on the left side and the N-type semiconductor (11) on the right side. The bottoms of the N-type semiconductor (11) on each connecting plate (10) and the P-type semiconductor (9) of the adjacent connecting plate (10) are connected into one body through the same corresponding lower connecting plate (8). The bottom of the P-type semiconductor (9) of the connecting plate (10) on the left edge is connected to the lower connecting plate (8) on this left edge, and the bottom of the N-type semiconductor (11) of the connecting plate (10) on the right edge is connected to the lower connecting plate (8) on this right edge. The lower connecting plate (8) on the left edge is connected to the negative pole of the DC power supply (7), and the lower connecting plate (8) on the right edge is connected in series with the temperature control switch (12) to the positive pole of the DC power supply (7); the radiator includes a heat dissipation channel (15) and a blower (14). Two blowers (14) are provided and are respectively located at both ends of the heat dissipation channel (15). The temperature control switch (12) is located inside the heat dissipation channel (15), and the lower bottom surface of the lower connecting plate (8) is embedded in the heat dissipation channel (15).

2. The fault diagnosis method of the IGBT module for a wind power frequency converter with a heat dissipation system according to claim 1, characterized in that: The electrically insulating thermal conductive adhesive (13) is a thermally conductive silica gel with good insulation and thermal conductivity.

3. The fault diagnosis method of the IGBT module for a wind power frequency converter with a heat dissipation system according to claim 1, characterized in that: The connecting plate (10) and the lower connecting plate (8) are made of metal plates with good thermal conductivity.

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