Over-temperature protection circuit of IGBT module

Abstract

The utility model discloses an over-temperature protection circuit of an IGBT module. The circuit comprises a temperature detection module, a temperature comparison module, an optocoupler isolation module, a heat dissipation module and a drive control module. The temperature detection module is used for detecting the working temperature of the IGBT module in real time; the input end of the temperature comparison module is connected with the output end of the temperature detection module, and the temperature comparison module is used for receiving the working voltage, output by the temperature detection module, of the IGBT module, comparing the working voltage with reference voltage and outputting a level signal after comparison; the input end of the heat dissipation module is connected with the output end of the temperature comparison module, and the state of the heat dissipation module is controlled by a level signal output by the temperature comparison module; the input end of the optocoupler isolation module is connected with the output end of the temperature comparison module, the input end of the driving control module is connected with the output end of the optocoupler isolation module, and the output end of the driving control module is connected with the IGBT tube. According to the utility model, the cooling effect of the IGBT module can be improved, and the working efficiency of the IGBT module can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the power electronics technical field especially relates to a kind of over-temperature protection circuit of IGBT module. BACKGROUND

[0002] IGBT module is a kind of composite full-control voltage drive type power semiconductor device, is widely used in various industrial equipment, such as servo motor, frequency converter, variable-frequency household appliance etc. IGBT module has excellent device performance, including control circuit is simple, switching loss is small, on-off speed is fast, and work frequency is higher advantage. However, IGBT module generates a large amount of heat in working process, if not heat dissipation or stop working in time, it can lead to IGBT module overheat damage, affect the normal operation of equipment. Therefore, over-temperature protection of IGBT module is crucial.

[0003] At present, IGBT module over-temperature protection method mainly includes temperature sensor detection method and current detection method. Temperature sensor detection method is to embed temperature sensor in IGBT module to monitor the temperature of IGBT in real time, and temperature sensor can accurately measure the temperature of IGBT, and trigger protection mechanism when temperature exceeds set threshold. Current detection method is to monitor the current of IGBT to indirectly judge its temperature, when IGBT is overloaded, current will increase, thereby causing temperature to rise, therefore, by monitoring the change of current, the temperature state of IGBT can be predicted, and protection measures can be taken when necessary.

[0004] But the above-mentioned two over-temperature protection methods have the problems of slow response speed, low precision, lack of corresponding cooling treatment, and poor over-temperature protection effect, which cannot effectively protect IGBT from over-temperature damage.

[0005] In the process of realizing the utility model, the inventor finds that there are at least the following problems in the prior art:

[0006] The over-temperature protection effect of the current IGBT module over-temperature protection method is poor, and the IGBT cannot be effectively protected from over-temperature. UTILITY MODEL CONTENTS

[0007] The utility model aims at providing an over-temperature protection circuit of IGBT module to solve the technical problem that the over-temperature protection effect of the IGBT module over-temperature protection method in the prior art is poor, and the IGBT cannot be effectively protected from over-temperature. The preferred technical solutions in many technical solutions provided by the utility model can produce many technical effects, which are described in detail below.

[0008] To achieve the above-mentioned purpose, the utility model provides the following technical solutions:

[0009] The utility model provides an overtemperature protection circuit of IGBT module, include: temperature detection module, temperature contrast module, photoelectric coupler isolation module, heat dissipation module and drive control module,

[0010] Temperature detection module is used for real -time detection to the working temperature of IGBT module,

[0011] The input of temperature contrast module is connected with the output of temperature detection module, is used for receiving the working voltage of IGBT module that temperature detection module outputs, and compares the working voltage with reference voltage, and the output level signal is outputted after comparison,

[0012] The input of heat dissipation module is connected with the output of temperature contrast module, and the state of heat dissipation module is controlled by the level signal that temperature contrast module outputs,

[0013] The input of photoelectric coupler isolation module is connected with the output of temperature contrast module, the input of drive control module is connected with the output of photoelectric coupler isolation module, and the output of drive control module is connected with IGBT tube.

[0014] Optionally, the heat dissipation module includes a transistor Q4 and a heat dissipation fan U3; the base of the transistor Q4 is connected with the output of the temperature contrast module, the collector is connected with the heat dissipation fan U3 and a power supply VCC1 respectively, and the emitter is grounded.

[0015] Optionally, the photoelectric coupler isolation module includes a transistor Q3 and a photoelectric coupler U2; the base of the transistor Q3 is connected with the output of the temperature contrast module, the collector is connected with a 5V power supply and a first pin of the photoelectric coupler U2 respectively, and the emitter is grounded; the second pin of the photoelectric coupler U2 is grounded, the third pin is grounded, and the fourth pin is connected with a 15V power supply and the input of the drive control module respectively.

[0016] Optionally, the temperature contrast module includes a comparator U1; the first pin of the comparator U1 is a negative input end and is connected with the output of the temperature detection module, the second pin is grounded, the third pin is a positive input end, is used for receiving the reference voltage input unit input reference voltage, the fourth pin is an output end and is connected with the input of the photoelectric coupler isolation module and the input of the heat dissipation module, the fifth pin is connected with a 5V power supply and is connected with the reference voltage input unit.

[0017] Optionally, the reference voltage input unit comprises resistors R6 and R7; one end of the resistor R6 is connected with the 5V power supply and the fifth pin of the comparator U1, and the other end is connected with one end of the resistor R7 and the third pin of the comparator U1; the other end of the resistor R7 is grounded; the resistor R6 and the resistor R7 constitute a voltage dividing network for determining the reference voltage of the positive input end of the comparator U1.

[0018] Optionally, the calculation formula of the reference voltage in the reference voltage input unit is:

[0019]

[0020] Optionally, the drive control module comprises a drive chip U4; the first pin of the drive chip U4 is connected with the 15V power supply and the output end of the optocoupler isolation module respectively, the second pin is used for receiving a high-side input signal, the third pin is used for receiving a low-side input signal, the fourth pin is grounded, the fifth pin is connected with the gate of the IGBT tube Q2 and is used for determining the gate drive signal of the IGBT tube Q2 according to the high-side input signal, and the seventh pin is connected with the gate of the IGBT tube Q1 and is used for determining the gate drive signal of the IGBT tube Q1 according to the low-side input signal.

[0021] Optionally, the drive control module further comprises a capacitor C2, and the capacitor C2 is connected in series between the sixth pin and the eighth pin of the drive chip U4.

[0022] Optionally, the temperature detection module comprises a thermistor R3 and a resistor R5, and the thermistor R3 is connected with the input end of the temperature comparison module through the resistor R5.

[0023] Optionally, the thermistor R3 is arranged in the IGBT module or close to the IGBT module.

[0024] The above technical solutions of the utility model have the following advantages or beneficial effects:

[0025] The over-temperature protection circuit of the IGBT module in the embodiment comprises a temperature detection module, a temperature comparison module, an optocoupler isolation module, a heat dissipation module and a drive control module. The temperature detection module is used for detecting the temperature of the IGBT module in real time during the working process, and sending the temperature converted into a working voltage to the temperature comparison module. The temperature comparison module compares the working voltage with a reference voltage, confirms whether the working voltage exceeds the reference voltage, and outputs different level signals according to whether the working voltage exceeds the reference voltage. The heat dissipation module and the optocoupler isolation module perform different actions according to the different level signals output by the temperature comparison module.

[0026] If the working voltage exceeds the reference voltage, the heat dissipation module is started, and the optocoupler isolation module outputs a corresponding signal to control the output of the drive control module, so that the drive control module does not output the drive control signal, and the IGBT stops working. After the subsequent temperature comparison module confirms that the working voltage does not exceed the reference voltage, the drive control module is restarted, so that the drive control module outputs the drive control signal, and the IGBT module restarts work. In this embodiment, when the working voltage exceeds the reference voltage, in addition to stopping the IGBT module from working, the heat dissipation module is also started to dissipate heat from the IGBT module, so that the IGBT cools down quickly, accelerates the cooling speed of the IGBT module, facilitates the IGBT module to quickly recover operation, improves the working efficiency, and also improves the service life of the IGBT module. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor. In the drawings:

[0028] Figure 1 is a circuit structure schematic diagram of the embodiment of the present application;

[0029] In the drawings: 100, temperature detection module; 200, temperature comparison module; 300, optocoupler isolation module; 400, heat dissipation module; 500, drive control module. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the present application more clear, the various exemplary embodiments to be described below will be referred to the corresponding drawings, which constitute a part of the exemplary embodiments, and various exemplary embodiments that can be used to realize the present application are described. Unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. It should be understood that they are only examples of processes, methods and devices, etc. consistent with some aspects of the present application as described in the appended claims, and other embodiments can also be used, or modifications can be made to the embodiments listed herein in structure and function, without departing from the scope and essence of the present application.

[0031] In the description of the utility model, it is necessary to understand that the terms "center", "longitudinal", "lateral" and the like indicate the orientation or positional relationship shown based on the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the indicated element must have a specific orientation, structure and operation. The terms "first", "second" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. The term "a plurality of" means two or more. The terms "connected", "connected" should be broadly understood, for example, it can be fixedly connected, detachably connected, integrally connected, mechanically connected, electrically connected, communicatively connected, directly connected, indirectly connected through an intermediate medium, and can be the internal communication of two elements or the interaction relationship of two elements. The term "and / or" includes any and all combinations of one or more related listed items. For ordinary skilled persons in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0032] In order to illustrate the technical scheme of the utility model, the following specific embodiments are used to illustrate, only the part related to the embodiment of the utility model is shown.

[0033] Embodiment:

[0034] As shown in Figure 1 The utility model provides a kind of over-temperature protection circuit of IGBT module, comprising: temperature detection module 100, temperature comparison module 200, opto-isolator module 300, heat dissipation module 400 and drive control module 500;Temperature detection module 100 is used to carry out real-time detection to the working temperature of IGBT module;The input end of temperature comparison module 200 is connected with the output end of temperature detection module 100, is used to receive the working voltage of IGBT module output by temperature detection module, and compares working voltage with reference voltage, and exports level signal after comparison;The input end of heat dissipation module 400 is connected with the output end of temperature comparison module 200, and the state of heat dissipation module 400 is controlled by the level signal exported by temperature comparison module 200;The input end of opto-isolator module 300 is connected with the output end of temperature comparison module 200, the input end of drive control module 500 is connected with the output end of opto-isolator module 300, and the output end of drive control module 500 is connected with IGBT tube;The state of opto-isolator module 300 is controlled by the level signal exported by temperature comparison module 200, and drive module is used to control the output of drive control module 500 according to the output signal of opto-isolator module 300, to switch the state of IGBT tube.

[0035] The over-temperature protection circuit of the IGBT module in the embodiment comprises a temperature detection module 100, a temperature comparison module 200, an optocoupler isolation module 300, a heat dissipation module 400 and a driving control module 500. The temperature detection module 100 is used to detect the working temperature of the IGBT module in real time during the working process, and convert the working temperature into a working voltage and send it to the temperature comparison module 200. The temperature comparison module 200 compares the working voltage with a reference voltage to confirm whether the working voltage exceeds the reference voltage. The temperature comparison module 200 outputs different level signals according to whether the working voltage exceeds the reference voltage.

[0036] If the working voltage exceeds the reference voltage, the heat dissipation module 400 will start, and the optocoupler isolation module 300 will output a corresponding signal to control the output of the driving control module 500, so that the driving control module 500 does not output a driving control signal, and the IGBT tube stops working. After the temperature comparison module 200 confirms that the working voltage does not exceed the reference voltage, the driving control module 500 is restarted to make the driving control module 500 output a driving control signal, so that the IGBT module starts working again. In the embodiment, when the working voltage exceeds the reference voltage, in addition to stopping the IGBT module from working, the heat dissipation module 400 is also started to dissipate heat from the IGBT module, so that the IGBT module cools down quickly, accelerates the cooling speed of the IGBT module, facilitates the IGBT module to quickly recover operation, improves the working efficiency, and also improves the service life of the IGBT module.

[0037] In the following, the specific structure of the over-temperature protection circuit of the IGBT module in the embodiment will be described in detail. Figure 1 The specific structure of the over-temperature protection circuit of the IGBT module in the embodiment will be described in detail.

[0038] The temperature detection module 100 comprises a thermistor R3 and a resistor R5. The thermistor R3 is connected to the input end of the temperature comparison module 200 through the resistor R5. Specifically, the thermistor R3 is an NTC thermistor, and the resistance value of the NTC thermistor decreases with the increase of temperature. The resistance value at normal temperature 25℃ is 10KΩ, and the resistance value at temperature 100℃ is 0.7KΩ. The thermistor R3 is connected to the input end of the temperature comparison module 200 through the resistor R5. The resistor R5 can limit the current to prevent the thermistor R3 from causing excessive current at extreme temperature, and can protect the comparator U1 in the temperature comparison module from being damaged.

[0039] The temperature detection module 100 further comprises a resistor R4 and a diode D1, one end of the resistor R4 is connected with the thermistor R3, the other end of the resistor R4 is connected with one end of the diode D1, and the other end of the diode D1 is grounded. The resistor R4 is used to limit the current through the diode D1, so as to prevent the diode D1 from being damaged due to excessive current. Meanwhile, the diode D1 can also ensure that the input voltage of the comparator U1 in the temperature comparison module will not exceed its safe working range. When the voltage divided by the resistor R4 exceeds the conduction voltage (usually about 0.7V) of the diode D1, the diode D1 is turned on, and the excess voltage is clamped to the ground, so as to protect the comparator U1 from being broken down by the excessive voltage.

[0040] Generally, in order to facilitate the thermistor R3 to better detect the working temperature of the IGBT module, the thermistor R3 is usually arranged inside the IGBT module or arranged outside the IGBT module close to the IGBT module.

[0041] The temperature comparison module 200 comprises a comparator U1, a first pin of the comparator U1 is a negative input end and connected with the output end of the temperature detection module 100, a second pin is grounded, a third pin is a positive input end and used to receive the reference voltage input by the reference voltage input unit, a fourth pin is an output end and connected with the input end of the opto-isolator module 300 and the input end of the heat dissipation module 400, and a fifth pin is connected with a 5V power supply and connected with the reference voltage input unit.

[0042] Specifically, the first pin of the comparator U1 is a negative input end and connected with the output end of the temperature detection module 100, and used to receive the working voltage detected by the temperature detection module 100. Since the thermistor R3 is connected with the negative input end of the temperature comparison module 200 through the resistor R5, the formula of the working voltage input by the temperature detection module 100 is:

[0043]

[0044] R3 is the resistance value of the resistor R3, and R5 is the resistance value of the resistor R5. If the resistance value of the resistor R5 is 78Ω, the resistance value of the resistor R3 is 10KΩ at normal temperature 25℃, then the working voltage V - is 0.039V; the resistance value of the resistor R3 is 0.7KΩ at 100℃, then the working voltage V - is 0.5V.

[0045] The second pin of the comparator U1 is grounded.

[0046] The third pin of the comparator U1 is a positive input end, which is connected with the reference voltage input unit and receives the reference voltage of the reference voltage input unit. The reference voltage input unit comprises resistors R6 and R7. One end of the resistor R6 is connected with the 5V power supply and the fifth pin of the comparator U1, and the other end is connected with one end of the resistor R7 and the third pin of the comparator U1. The other end of the resistor R7 is grounded. The resistors R6 and R7 form a voltage dividing network for determining the reference voltage of the positive input end of the comparator U1. The calculation formula of the reference voltage in the reference voltage input unit is:

[0047]

[0048] The resistor R6 is the resistance value of the resistor R6, and the resistor R7 is the resistance value of the resistor. When the resistance value of the resistor R6 is 9KΩ and the resistance value of the resistor R7 is 1KΩ, the reference voltage Vref is 0.5V.

[0049] The fourth pin of the comparator U1 is an output end, which is connected with the input end of the opto-isolator circuit and the input end of the heat dissipation module 400 respectively, and is used for outputting a level signal to control the opto-isolator circuit and the heat dissipation circuit.

[0050] In addition, the temperature comparison module 200 further comprises a resistor R8, one end of which is connected with the fourth pin of the comparator U4, and the other end of which is connected with the reference voltage input unit. The resistor R8 serves as a positive feedback resistor. When the fourth pin of the comparator U1 outputs a high level, the resistor R8 slightly increases the reference voltage of the reference voltage input unit. When the fourth pin of the comparator U1 outputs a low level, the resistor R8 slightly reduces the reference voltage of the reference voltage input unit. The setting of the resistor R8 enables the comparator U1 to obtain a hysteresis characteristic, so that the comparator U1 does not frequently switch states when the input signal is close to the threshold value, thereby avoiding false triggering caused by noise. The comparator U1 has different threshold voltages at rising and falling edges. According to the characteristics of the comparator and the thermistor, the resistance values of R6, R7, R3, R5 and R8 can be adjusted to realize the comparison between the actual temperature and the threshold temperature.

[0051] It should be noted that when the temperature comparison module 200 compares and obtains that the working voltage of the temperature detection module 100 is less than the reference voltage, a high level (5V) is output. When the temperature comparison module 200 compares and obtains that the working voltage of the temperature detection module 100 is greater than the reference voltage, a low level (0V) is output.

[0052] The heat dissipation module 400 comprises a transistor Q4 and a heat dissipation fan U3. The base of the transistor Q4 is connected with the output end of the temperature comparison module 200, the collector is connected with the heat dissipation fan U3 and the power supply VCC1 respectively, and the emitter is grounded.

[0053] Specifically, the base of the triode Q4 is connected with the output end of the temperature comparison module 200 through the resistor R10. When the temperature comparison module 200 outputs a high level, the triode Q4 is turned on, the input voltage of VCC1 is pulled down to the ground, and the cooling fan U3 is not started. When the temperature comparison module 200 outputs a low level, the triode Q4 is cut off, the input voltage of VCC1 is supplied to the cooling fan U3 through the resistor R13, at this time, the cooling fan is started, and the IGBT module is cooled, so that the IGBT module is quickly cooled. The resistor R10 is a protection resistor for current limiting protection to ensure the normal work of the triode, and the resistor R13 is a protection resistor for current limiting protection.

[0054] The optical coupling isolation module 300 includes the triode Q3 and the optical coupling U2. The base of the triode Q3 is connected with the output end of the temperature comparison module 200, the collector is connected with the 5V power supply and the first pin of the optical coupling U2 respectively, and the emitter is grounded. The second pin of the optical coupling U2 is grounded, the third pin is grounded, and the fourth pin is connected with the 15V power supply and the input end of the drive control module 500 respectively.

[0055] Specifically, the base of the triode Q3 is connected with the output end of the temperature comparison module 200 through the resistor R9, and the collector is connected with the 5V power supply through the resistor R11. The first pin of the optical coupling U2 is connected with the 5V power supply through the resistor R12, and the fourth pin of the optical coupling U2 is connected with the input end of the drive control module 500. The resistors R11 and R12 are protection resistors for current limiting protection.

[0056] The drive control module 500 includes the drive chip U4. The first pin of the drive chip U4 is connected with the 15V power supply and the output end of the optical coupling isolation module 300 respectively, the second pin is used for receiving a high-side input signal, the third pin is used for receiving a low-side input signal, the fourth pin is grounded, the fifth pin is connected with the gate of the IGBT tube Q2, and is used for determining the gate drive signal of the IGBT tube Q2 according to the high-side input signal, and the seventh pin is connected with the gate of the IGBT tube Q1, and is used for determining the gate drive signal of the IGBT tube Q1 according to the low-side input signal.

[0057] Specifically, the first pin of the drive chip U4 is connected with the fourth pin of the optical coupling isolation module 300 through the resistor R15, and is connected with the 15V power supply through the resistor R15 and the resistor R14. The resistors R14 and R15 are protection resistors for current limiting protection.

[0058] The fourth pin and the first pin of the driving chip U4 are connected in series with a capacitor C1, which is used for decoupling and filtering, and can improve the stability of the power supply. The sixth pin and the eighth pin of the driving chip are connected in series with a capacitor C2, which is used for decoupling and filtering, maintaining the stability of the bootstrap voltage, and accelerating the response speed. The first pin and the eighth pin of the driving chip are connected in series with a resistor R16 and a diode D2, which work together to ensure the safety and stability of the circuit. The resistor R16 limits the current to prevent overloading of the diode and the circuit; the diode D2 prevents reverse voltage and overvoltage to protect the power supply and the circuit. In the half-bridge driving circuit, the above structure can effectively charge the bootstrap capacitor and provide the gate drive voltage required by the high-side IGBT tube, ensuring the normal operation of the circuit. The HIN of the driving chip U4 is a high-side input signal, and the output is HO, which is the gate drive signal of the IGBT tube Q1; the LIN of the driving chip U4 is a low-side input signal, and the output is LO, which is the gate drive signal of the IGBT tube Q2.

[0059] Specifically, when the temperature comparison module 200 outputs a high level, the triode Q3 is turned on, the 5V power supply is pulled low to the ground, the light-emitting diode in the optocoupler U2 is not conductive and does not emit light, the phototransistor is also not conductive, the fourth pin of the optocoupler U2 outputs a low level, the 15V power supply delivers voltage to the driving chip U4, which supplies power to the driving chip U4, and the IGBT tube Q1 and the IGBT tube Q2 work normally. When the temperature comparison module 200 outputs a low level, the triode Q3 is cut off, the input of the optocoupler U2 is the 5V power supply, the light-emitting diode in the optocoupler is conductive and emits light, the phototransistor is conductive, the fourth pin of the optocoupler U2 outputs a high level, the 15V power supply is pulled to the ground, the driving chip U4 is not powered, the driving chip U4 does not output a driving signal, and the IGBT tube Q1 and the IGBT tube Q2 stop working.

[0060] It should be noted that the seventh pin of the driving chip U4 is connected to the IGBT tube Q1 through a resistor R1, and the fifth pin of the driving chip U4 is connected to the IGBT tube Q2 through a resistor R2. Among them, the resistor R1 is the driving resistor of the IGBT tube Q1, and the resistor R2 is the driving resistor of the IGBT tube Q2, which is used to adjust the turn-on speed of the IGBT tube.

[0061] The working process of the over-temperature protection circuit of the IGBT module in this embodiment is as follows:

[0062] When the module temperature is lower than the protection temperature, the thermistor R3 collects the temperature inside or outside the IGBT module, and the collected temperature is compared with the preset reference voltage through the comparator U1, when the positive input voltage of the comparator U1 is greater than the negative input voltage, the comparator U1 outputs 5V. The transistor Q3 is turned on, 5V is pulled to the ground, the light emitting diode of the optocoupler U2 is not turned on and emits no light, the photo transistor is not turned on, the fourth pin of the optocoupler U2 outputs low voltage, the 15V power supply is connected to the first pin (VCC) of the driving chip through R14 and R15, the driving chip U4 is powered, and the IGBT Q1 and the IGBT Q2 work normally. The transistor Q4 is turned on, VCC1 is pulled to the ground, the cooling fan U3 is not powered, and the cooling fan U3 is not started.

[0063] When the module temperature reaches the set threshold temperature, the thermistor R3 collects the temperature inside or outside the IGBT module, and the collected temperature is compared with the preset reference voltage through the comparator U1, when the negative input voltage of the comparator U1 is greater than the positive input voltage, the comparator U1 outputs 0V. The transistor Q3 is not turned on, the positive electrode of the light emitting diode of the optocoupler U2 is +5V, the diode is turned on and emits light, the photo transistor is turned on, 15V is pulled to the ground, the driving chip U4 is not powered, no driving signal is output, the IGBT Q1 and the IGBT Q2 stop working. The transistor Q4 is not turned on, VCC1 supplies power to the cooling fan U3 through the resistor R13, the cooling fan U3 is started, and cooling treatment is performed. When the temperature collected by the thermistor R3 is lower than the threshold temperature, the cooling fan U3 stops rotating, the driving chip U4 is powered again, and the IGBT Q1 and the IGBT Q2 return to the working state.

[0064] The embodiment is only one special case, and does not indicate that the utility model is such an implementation mode.

[0065] The above is only a preferred embodiment of the utility model, and those skilled in the art know that various changes or equivalent replacements can be made to the features and embodiments without departing from the spirit and range of the utility model. In addition, the features and embodiments can be modified to adapt to specific conditions and materials under the guidance of the utility model without departing from the spirit and range of the utility model. Therefore, the utility model is not limited by the specific embodiments disclosed here, and all embodiments falling within the scope of the claims of the application belong to the protection range of the utility model.

Claims

1. An over-temperature protection circuit for an IGBT module, characterized in that, include: Temperature detection module, temperature comparison module, optocoupler isolation module, heat dissipation module, and drive control module; The temperature detection module is used to detect the operating temperature of the IGBT module in real time. The input terminal of the temperature comparison module is connected to the output terminal of the temperature detection module, and is used to receive the operating voltage of the IGBT module output by the temperature detection module, compare the operating voltage with the reference voltage, and output a level signal after comparison. The input terminal of the heat dissipation module is connected to the output terminal of the temperature comparison module, and the state of the heat dissipation module is controlled by the level signal output by the temperature comparison module. The input terminal of the optocoupler isolation module is connected to the output terminal of the temperature comparison module, the input terminal of the drive control module is connected to the output terminal of the optocoupler isolation module, and the output terminal of the drive control module is connected to the IGBT transistor.

2. The over-temperature protection circuit for the IGBT module according to claim 1, characterized in that, The heat dissipation module includes a transistor Q4 and a cooling fan U3; the base of the transistor Q4 is connected to the output terminal of the temperature comparison module, the collector is connected to the cooling fan U3 and the power supply VCC1 respectively, and the emitter is grounded.

3. The over-temperature protection circuit for the IGBT module according to claim 1, characterized in that, The optocoupler isolation module includes a transistor Q3 and an optocoupler U2; the base of the transistor Q3 is connected to the output terminal of the temperature comparison module, the collector is connected to the 5V power supply and the first pin of the optocoupler U2, and the emitter is grounded; the second pin of the optocoupler U2 is grounded, the third pin is grounded, and the fourth pin is connected to the 15V power supply and the input terminal of the drive control module.

4. The over-temperature protection circuit for the IGBT module according to claim 1, characterized in that, The temperature comparison module includes a comparator U1; the first pin of the comparator U1 is the negative input terminal and is connected to the output terminal of the temperature detection module; the second pin is grounded; the third pin is the positive input terminal and is used to receive the reference voltage input by the reference voltage input unit; the fourth pin is the output terminal and is connected to the input terminal of the optocoupler isolation module and the input terminal of the heat dissipation module; the fifth pin is connected to the 5V power supply and is connected to the reference voltage input unit.

5. The over-temperature protection circuit for the IGBT module according to claim 4, characterized in that, The reference voltage input unit includes resistors R6 and R7; one end of resistor R6 is connected to the 5V power supply and the fifth pin of comparator U1, and the other end is connected to one end of resistor R7 and the third pin of comparator U1; the other end of resistor R7 is grounded; resistors R6 and R7 form a voltage divider network to determine the reference voltage at the positive input terminal of comparator U1.

6. The over-temperature protection circuit for the IGBT module according to claim 5, characterized in that, The formula for calculating the reference voltage in the reference voltage input unit is as follows:

7. The over-temperature protection circuit for the IGBT module according to claim 1, characterized in that, The drive control module includes a drive chip U4; the first pin of the drive chip U4 is connected to the 15V power supply and the output terminal of the optocoupler isolation module respectively, the second pin is used to receive the high-side input signal, the third pin is used to receive the low-side input signal, the fourth pin is grounded, the fifth pin is connected to the gate of IGBT Q2 and is used to determine the gate drive signal of IGBT Q2 according to the high-side input signal, and the seventh pin is connected to the gate of IGBT Q1 and is used to determine the gate drive signal of IGBT Q1 according to the low-side input signal.

8. The over-temperature protection circuit for the IGBT module according to claim 7, characterized in that, The drive control module also includes a capacitor C2, which is connected in series between the sixth and eighth pins of the drive chip U4.

9. The over-temperature protection circuit for the IGBT module according to any one of claims 1-8, characterized in that, The temperature detection module includes a thermistor R3 and a resistor R5. The thermistor R3 is connected to the input terminal of the temperature comparison module through the resistor R5.

10. The over-temperature protection circuit for the IGBT module according to claim 9, characterized in that, The thermistor R3 is disposed inside or near the IGBT module.

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