IGBT power module signal transmission circuit

Abstract

The utility model relates to the technical field of power modules, in particular to an IGBT power module signal transmission circuit, which comprises a main control chip, an isolation circuit, a push-pull circuit, an IGBT power module and a protection circuit, the main control chip, the isolation circuit, the push-pull circuit and the IGBT power module are electrically connected in sequence, an input end of the isolation circuit is connected with a PWM signal output by the main control chip, and an output end of the protection circuit is connected with the IGBT power module. The protection circuit comprises a sampling circuit and an analog-to-digital conversion chip which are electrically connected. An output port of the analog-to-digital conversion chip is connected with an input port of the main control chip. According to the utility model, the isolation circuit isolates a front-stage circuit and a rear-stage circuit, so that the stability and the reliability are improved, the push-pull circuit can accelerate the switching speed and improve the working efficiency and the response speed, the working data of the IGBT power module are obtained through the sampling circuit and the analog-to-digital conversion chip, and when the IGBT power module goes wrong, the main control chip timely turns off the IGBT power module, so that the IGBT power module is protected. The fault risk is reduced.

Description

Technical Field

[0001] This utility model relates to the field of power module technology, and more specifically, to the signal transmission circuit of IGBT power module. Background Technology

[0002] In the field of power module technology, IGBT power modules are widely used in various power electronic devices, such as drive systems for new energy vehicles, variable frequency speed control devices for industrial motors, and uninterruptible power supplies, due to their excellent performance, such as high voltage, high current handling capability and low conduction loss.

[0003] However, signal transmission faces numerous challenges in the practical application of IGBT power modules. On the one hand, a potential difference exists between the main control chip and the IGBT power module. If the signal transmission circuit does not implement proper isolation measures, high voltage can be introduced into the low voltage system, damaging low-voltage devices such as the main control chip, reducing system stability and reliability, affecting normal equipment operation, and even causing safety accidents. On the other hand, the switching speed of the IGBT power module is crucial to the system's performance and efficiency. A slow switching speed increases switching losses, wastes energy, and may prevent the equipment's response speed from meeting actual needs. Furthermore, due to the complex operating environment, IGBT power modules are susceptible to abnormal conditions such as overvoltage and overcurrent. The lack of effective protection mechanisms can lead to module damage, increasing equipment maintenance costs and downtime. Utility Model Content

[0004] The purpose of this invention is to provide a signal transmission circuit for an IGBT power module to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] The IGBT power module signal transmission circuit includes a main control chip, an isolation circuit, a push-pull circuit, an IGBT power module, and a protection circuit. The main control chip, the isolation circuit, the push-pull circuit, and the IGBT power module are electrically connected in sequence. The input terminal of the isolation circuit is connected to the PWM signal output by the main control chip. The push-pull circuit is used to improve the switching speed of the IGBT power module. The protection circuit includes a sampling circuit and an analog-to-digital converter chip that are electrically connected. The sampling circuit is used to acquire the analog voltage data of the IGBT power module, and the analog-to-digital converter chip is used to convert the analog voltage data into digital voltage data. The output port of the analog-to-digital converter chip is connected to the input port of the main control chip.

[0007] Preferably, the isolation circuit includes a transistor Q1, a power supply VCC, an optocoupler U1, and a resistor R1. The transistor Q1 is an NPN transistor. The base of the transistor Q1 is connected to the output port of the main control chip, the collector of the transistor Q1 is connected to the negative terminal of the optocoupler U1, the emitter of the transistor Q1 is grounded, the positive terminal of the optocoupler U1 is connected to the power supply VCC, the first end of the resistor R1 is connected to the power supply VCC, the second end of the resistor R1 is connected to the collector of the optocoupler U1, and the emitter of the optocoupler U1 is grounded.

[0008] Preferably, the push-pull circuit includes a resistor R2, a transistor Q2, a transistor Q3, a resistor R3, a diode D1, and a resistor R4. Transistor Q2 is an NPN transistor, and transistor Q3 is a PNP transistor. The first terminal of resistor R2 is connected to the second terminal of resistor R1. The bases of transistors Q2 and Q3 are both connected to the second terminal of resistor R2. The collector of transistor Q2 is connected to the power supply VCC, and the emitter of transistor Q2 is connected to the emitter of transistor Q3. The collector of transistor Q3 is grounded. The first terminal of resistor R3 is connected to the emitter of transistor Q2, and the second terminal of resistor R3 is connected to the gate of the IGBT power module. The anode of diode D1 is connected to the gate of the IGBT power module, and the cathode of diode D1 is connected to the first terminal of resistor R3. The first terminal of resistor R4 is connected to the second terminal of resistor R3, and the second terminal of resistor R4 is connected to the emitter of the IGBT power module.

[0009] Preferably, the sampling circuit includes resistors R5 and R6 and a voltage follower U2. Resistor R5 is connected in series in the circuit at one end of the collector of the IGBT power module, the second end of resistor R5 is connected to the collector of the IGBT power module, the first end of resistor R6 is grounded, the second end of resistor R6 is connected to the second end of resistor R5, the non-inverting input of voltage follower U2 is connected to the second end of resistor R5, the inverting input of voltage follower U2 is connected to the output of voltage follower U2, and the output of voltage follower U2 is connected to the analog-to-digital converter chip.

[0010] Compared with the prior art, the beneficial effects of this utility model are:

[0011] This invention uses an isolation circuit to convert the electrical signal output by the main control chip into an optical signal for transmission, and then converts it back into an electrical signal for input to subsequent circuits. This isolation between the preceding and following stages improves the stability and reliability of the entire system. The push-pull circuit accelerates the switching speed of the IGBT power module, improving its working efficiency and response speed. Furthermore, by using a sampling circuit and an analog-to-digital converter chip to acquire the working data of the IGBT power module, the main control chip can promptly shut down the IGBT power module when a problem occurs, reducing the risk of IGBT power module failure. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of the utility model;

[0013] Figure 2 This is a schematic diagram showing the connection of the isolation circuit, push-pull circuit, and IGBT power module in the utility model.

[0014] Figure 3 This is a schematic diagram of the protection circuit in the utility model.

[0015] Figure 4 This is a schematic diagram of the connection of the protection circuit in the utility model;

[0016] In the picture:

[0017] 1. Main control chip;

[0018] 2. Isolation circuit;

[0019] 3. Push-pull circuit;

[0020] 4. IGBT power module;

[0021] 5. Protection circuit; 50. Sampling circuit; 51. Analog-to-digital converter chip. Detailed Implementation

[0022] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0023] Please see Figures 1-4 The present invention provides the following technical solution:

[0024] The IGBT power module signal transmission circuit includes a main control chip 1, an isolation circuit 2, a push-pull circuit 3, an IGBT power module 4, and a protection circuit 5. The main control chip 1, isolation circuit 2, push-pull circuit 3, and IGBT power module 4 are electrically connected in sequence. The input terminal of the isolation circuit 2 is connected to the PWM signal output from the main control chip 1. The push-pull circuit 3 is used to improve the switching speed of the IGBT power module 4. The protection circuit 5 includes a sampling circuit 50 and an analog-to-digital converter chip 51 electrically connected. The sampling circuit 50 is used to acquire the analog voltage data of the IGBT power module 4, and the analog-to-digital converter chip 51 is used to convert the analog voltage data into digital voltage data. The output port of the analog-to-digital converter chip 51 is connected to the input port of the main control chip 1. The main control chip 1, as the control core, generates the PWM signal according to a preset program. The frequency and duty cycle of the PWM signal determine the switching speed of the IGBT power module 4. The on and off times control the output power of the IGBT power module 4. The isolation circuit 2 effectively isolates the weak current system where the main control chip 1 is located from the strong current system where the IGBT power module 4 is located, preventing the strong current from entering the weak current system and causing damage to low-voltage devices such as the main control chip 1, thus ensuring stable operation. The push-pull circuit 3 can quickly charge and discharge the gate of the IGBT power module 4 after receiving the output signal of the isolation circuit 2, significantly improving the switching speed of the IGBT power module 4. The sampling circuit 50 acquires the analog voltage data of the collector of the IGBT power module 4, and the analog-to-digital converter chip 51 converts it into digital voltage data, reflecting the voltage change of the IGBT power module 4 and whether there is overvoltage, etc., which is convenient for the main control chip 1 to analyze and process, so that the main control chip 1 can detect the abnormal situation of the IGBT power module 4 in time and take corresponding measures.

[0025] In this embodiment, please refer to Figure 2 The isolation circuit 2 includes a transistor Q1, a power supply VCC, an optocoupler U1, and a resistor R1. The transistor Q1 is an NPN transistor. The base of transistor Q1 is connected to the output port of the main control chip 1, the collector of transistor Q1 is connected to the negative terminal of optocoupler U1, and the emitter of transistor Q1 is grounded. The positive terminal of optocoupler U1 is connected to the power supply VCC. The first end of resistor R1 is connected to the power supply VCC, the second end of resistor R1 is connected to the collector of optocoupler U1, and the emitter of optocoupler U1 is grounded. When the main control chip 1 outputs a PWM signal, the base of transistor Q1 receives a high level and conducts. At this time, the LED in optocoupler U1 works, and the phototransistor in optocoupler U1 conducts. The isolation circuit 2 outputs a high level. When the base of transistor Q1 receives a low level, it is cut off. At this time, the LED in optocoupler U1 does not work, and the phototransistor in optocoupler U1 is cut off. The isolation circuit 2 outputs a low level, realizing electrical isolation between the preceding and following stages.

[0026] Specifically, please refer to Figure 2The push-pull circuit 3 includes resistor R2, transistor Q2, transistor Q3, resistor R3, diode D1, and resistor R4. Transistor Q2 is an NPN transistor, and transistor Q3 is a PNP transistor. The first terminal of resistor R2 is connected to the second terminal of resistor R1. The bases of transistors Q2 and Q3 are both connected to the second terminal of resistor R2. The collector of transistor Q2 is connected to the power supply VCC, and the emitter of transistor Q2 is connected to the emitter of transistor Q3. The collector of transistor Q3 is grounded. The first terminal of resistor R3 is connected to the emitter of transistor Q2, and the second terminal of resistor R3 is connected to the gate of IGBT power module 4. The anode of diode D1 is connected to the gate of IGBT power module 4, and the cathode of diode D1 is connected to the first terminal of resistor R3. The first terminal of resistor R4 is connected to the second terminal of resistor R3, and the second terminal of resistor R4 is connected to the emitter of IGBT power module 4. When the output signal of isolation circuit 2 is high, transistor Q2 is turned on, and transistor Q3 is turned off. The source VCC provides a high-level drive signal to the gate of the IGBT power module 4 through transistor Q2 and resistor R3, enabling the IGBT power module 4 to conduct quickly. Diode D1 is in reverse cutoff during this process, which does not affect normal signal transmission and circuit operation. It mainly plays a protective role, preventing abnormal voltage at the gate of the IGBT power module 4 from damaging the circuit. Resistor R4 acts as a voltage divider to ensure the stability of the gate drive signal of the IGBT power module 4, and also limits the current to avoid excessive current damaging the gate of the IGBT power module 4. When the output signal of isolation circuit 2 is low, transistor Q2 is cut off and transistor Q3 is turned on. The charge on the gate of the IGBT power module 4 is quickly discharged through transistor Q3 and resistor R4, enabling the IGBT power module 4 to turn off quickly. Push-pull circuit 3 greatly accelerates the switching speed of IGBT power module 4.

[0027] In addition, please see Figure 4The sampling circuit 50 includes resistors R5 and R6, and a voltage follower U2. Resistor R5 is connected in series in the circuit at one end of the collector of the IGBT power module 4, and the second end of resistor R5 is connected to the collector of the IGBT power module 4. The first end of resistor R6 is grounded, and the second end of resistor R6 is connected to the second end of resistor R5. The non-inverting input of voltage follower U2 is connected to the second end of resistor R5, and the inverting input of voltage follower U2 is connected to the output of voltage follower U2. The output of voltage follower U2 is connected to analog-to-digital converter chip 51. Resistors R5 and R6 form a voltage divider circuit. The voltage at the collector of the IGBT power module 4 is usually high, and direct measurement may exceed the measurement range of analog-to-digital converter chip 51. Through the voltage divider circuit, the voltage can be adjusted to the range of analog-to-digital converter chip 51. Within the appropriate range that the replacement chip 51 can handle, the non-inverting input of the voltage follower U2 is connected to the divided signal, and its inverting input is connected to the output. This connection method makes the output voltage of the voltage follower U2 equal to the input voltage, and it has extremely high input impedance and low output impedance. The high input impedance ensures that the voltage follower U2 has minimal impact on the voltage divider circuit after being connected to the circuit, ensuring that the voltage divider circuit can work stably. The low output impedance allows the voltage follower U2 to stably transmit the divided analog voltage signal to the analog-to-digital converter chip 51. The analog-to-digital converter chip 51 converts the received analog voltage signal into a digital signal and transmits it to the main control chip 1. The main control chip 1 judges the working status of the IGBT power module 4 based on these digital signals. Upper and lower thresholds can be set in the program of the main control chip 1, and it can judge whether there are abnormal conditions such as overvoltage or overcurrent. Once an abnormality is detected, the main control chip 1 will take timely measures, such as shutting down the IGBT power module 4, to protect the entire circuit system.

[0028] Finally, it should be noted that the process algorithm and program involved in the operation of the main control chip 1 connecting to the analog-to-digital converter chip 51 to transmit signals in this embodiment are not within the protection scope of this utility model, and the process algorithm and program involved can be obtained by those skilled in the art through conventional technology. Therefore, it is only used for those skilled in the art to understand the electronic circuit connection relationship of the display circuit in this embodiment.

[0029] In use, the IGBT power module signal transmission circuit of this utility model outputs a PWM signal from the main control chip 1. This signal is input to the isolation circuit 2. The transistor Q1, optocoupler U1, and other components in the isolation circuit 2 work together to convert the electrical signal into an optical signal for transmission, achieving isolation between the front and rear circuits, preventing high voltage from entering the low voltage system, and ensuring system stability. The isolated signal enters the push-pull circuit 3. The transistors Q2 and Q3 in the push-pull circuit 3 cooperate to quickly charge and discharge the gate of the IGBT power module 4, improving its switching speed, working efficiency, and response speed. At the same time, the resistors R5 and R6 in the sampling circuit 50 form a voltage divider circuit to obtain the analog voltage data of the collector of the IGBT power module 4. The voltage follower U2 stably transmits this data to the analog-to-digital converter chip 51. The analog-to-digital converter chip 51 converts the analog data into digital data and transmits it to the main control chip 1. The main control chip 1 monitors the working status of the IGBT power module 4 based on this data. Once an abnormality is detected, the IGBT power module 4 is shut down in time to reduce the risk of failure.

[0030] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. An IGBT power module signal transmission circuit, characterized in that: The system includes a main control chip (1), an isolation circuit (2), a push-pull circuit (3), an IGBT power module (4), and a protection circuit (5). The main control chip (1), the isolation circuit (2), the push-pull circuit (3), and the IGBT power module (4) are electrically connected in sequence. The input terminal of the isolation circuit (2) is connected to the PWM signal output by the main control chip (1). The push-pull circuit (3) is used to improve the switching speed of the IGBT power module (4). The protection circuit (5) includes a sampling circuit (50) and an analog-to-digital converter chip (51) that are electrically connected. The sampling circuit (50) is used to acquire the analog voltage data of the IGBT power module (4). The analog-to-digital converter chip (51) is used to convert the analog voltage data into digital voltage data. The output port of the analog-to-digital converter chip (51) is connected to the input port of the main control chip (1).

2. The IGBT power module signal transmission circuit according to claim 1, characterized in that: The isolation circuit (2) includes a transistor Q1, a power supply VCC, an optocoupler U1, and a resistor R1. The transistor Q1 is an NPN transistor. The base of the transistor Q1 is connected to the output port of the main control chip (1). The collector of the transistor Q1 is connected to the negative terminal of the optocoupler U1. The emitter of the transistor Q1 is grounded. The positive terminal of the optocoupler U1 is connected to the power supply VCC. The first end of the resistor R1 is connected to the power supply VCC. The second end of the resistor R1 is connected to the collector of the optocoupler U1. The emitter of the optocoupler U1 is grounded.

3. The IGBT power module signal transmission circuit according to claim 2, characterized in that: The push-pull circuit (3) includes a resistor R2, a transistor Q2, a transistor Q3, a resistor R3, a diode D1, and a resistor R4. Transistor Q2 is an NPN transistor, and transistor Q3 is a PNP transistor. The first end of resistor R2 is connected to the second end of resistor R1. The bases of transistors Q2 and Q3 are both connected to the second end of resistor R2. The collector of transistor Q2 is connected to the power supply VCC. The emitter of transistor Q2 is connected to the emitter of transistor Q3. The collector of transistor Q3 is grounded. The first end of resistor R3 is connected to the emitter of transistor Q2. The second end of resistor R3 is connected to the gate of the IGBT power module (4). The anode of diode D1 is connected to the gate of the IGBT power module (4). The cathode of diode D1 is connected to the first end of resistor R3. The first end of resistor R4 is connected to the second end of resistor R3. The second end of resistor R4 is connected to the emitter of the IGBT power module (4).

4. The IGBT power module signal transmission circuit according to claim 1, characterized in that: The sampling circuit (50) includes resistors R5 and R6 and voltage follower U2. Resistor R5 is connected in series in the line of one end of the collector of the IGBT power module (4). The second end of resistor R5 is connected to the collector of the IGBT power module (4). The first end of resistor R6 is grounded. The second end of resistor R6 is connected to the second end of resistor R5. The non-inverting input of voltage follower U2 is connected to the second end of resistor R5. The inverting input of voltage follower U2 is connected to the output of voltage follower U2. The output of voltage follower U2 is connected to the analog-to-digital converter chip (51).

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