A SiC-IGBT hybrid power module steady-state current distribution ratio modulation circuit

Abstract

This utility model relates to the field of motor controller technology, specifically a steady-state current distribution ratio modulation circuit for a SiC-IGBT hybrid power module. The circuit includes a hybrid power module, a PWM push-pull circuit, a current sampling and junction temperature estimation module, an MCU chip, and a drive power switching circuit. The hybrid power module is connected to the PWM push-pull circuit and the current sampling and junction temperature estimation module. The current sampling and junction temperature estimation module is connected to the MCU chip. The MCU chip is connected to the drive power switching circuit. The drive power switching circuit is connected to the PWM push-pull circuit. This utility model achieves current distribution between the SiC wafer and the IGBT wafer through the SiC drive power switching circuit and the IGBT drive power switching circuit, controlling the current carried by the SiC wafer, thereby adjusting the junction temperature of the SiC wafer and the IGBT wafer. This avoids the problem of the power module overheating and being damaged due to excessive current carried by the SiC wafer.

Description

Technical Field

[0001] This utility model relates to the field of motor controller technology, specifically a steady-state current distribution ratio modulation circuit for a SiC-IGBT hybrid power module. Background Technology

[0002] The motor controller is a key component of electric vehicles and a decisive factor in the vehicle's power performance. It obtains the vehicle's requirements from the overall vehicle controller and electrical energy from the power battery pack. After modulation by its own inverter, it obtains the current and voltage needed to control the motor and supplies it to the motor, ensuring that the motor's speed and torque meet the vehicle's requirements.

[0003] Motor controllers often use hybrid power modules of SiC and IGBT as output devices. SiC power modules can improve the power level of the motor controller and reduce its losses, thereby improving the efficiency of the motor controller and thus increasing the driving range.

[0004] Because SiC wafers are expensive to produce, the cost of hybrid power modules using SiC and IGBTs is reduced by decreasing the amount of SiC wafers used. However, using too few SiC wafers can cause excessive current sharing by the SiC wafers, which can damage the entire power module.

[0005] In view of this, we propose a steady-state current distribution ratio modulation circuit for SiC-IGBT hybrid power modules. Utility Model Content

[0006] The purpose of this invention is to provide a steady-state current distribution ratio modulation circuit for a SiC-IGBT hybrid power module, so as to solve the problem of excessive current sharing by the SiC wafer leading to overheating and damage to the power module mentioned in the background art.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A steady-state current distribution ratio modulation circuit for a SiC-IGBT hybrid power module includes a hybrid power module, a PWM push-pull circuit, a current sampling and junction temperature estimation module, an MCU chip, and a drive power switching circuit. The hybrid power module is connected to the PWM push-pull circuit. The PWM push-pull circuit drives the hybrid power module by receiving and amplifying a PWM signal. The hybrid power module has a SiC wafer and an IGBT wafer. The PWM push-pull circuit amplifies the PWM signal to drive the hybrid power module, which in turn drives the SiC wafer and IGBT wafer on the hybrid power module. The SiC wafer and IGBT wafer work complementaryly to ensure stable circuit operation. Simultaneously, the hybrid use of SiC and IGBT wafers reduces the SiC wafer usage in the SiC power module, thereby reducing production costs. The hybrid power module is connected to the current sampling and junction temperature estimation module. The current sampling and junction temperature estimation module controls the current flowing through the hybrid power module. The power module's current is sampled in real time, and the junction temperature of the SiC wafer and IGBT wafer is estimated based on the current magnitude. This current sampling and junction temperature estimation module is connected to the MCU chip, transmitting the estimated junction temperature results to the MCU chip. The MCU chip is connected to the drive power switching circuit, which is also connected to a PWM push-pull circuit block. This drive power switching circuit is used to adjust the junction temperature of the SiC and IGBT wafers. The MCU chip controls the drive power switching circuit based on the junction temperature estimation results from the current sampling and junction temperature estimation module, changing the power supply magnitude and thus altering the equivalent series resistance of the SiC and IGBT wafers. This changes the current flowing through the SiC and IGBT wafers, thereby controlling their junction temperature and preventing overheating and damage to the power module caused by excessive current on the SiC wafer.

[0009] Preferably, the current sampling circuit and junction temperature estimation module include a current sampling circuit and a junction temperature estimation unit; the current sampling circuit is connected to the hybrid power module and the junction temperature estimation unit respectively, and the current sampling circuit is used to sample the current flowing through the hybrid power module in real time; the current sampling circuit samples the current flowing through the hybrid power module in real time, which facilitates real-time monitoring of the current in the circuit, and at the same time, the current sampling circuit transmits the sampled current data to the junction temperature estimation unit;

[0010] The junction temperature estimation unit is connected to both the current sampling circuit and the MCU chip. This unit is used to estimate the junction temperature of the SiC wafer and IGBT wafer in real time. It receives real-time sampling data from the current sampling circuit and performs calculations to estimate the junction temperature of the SiC and IGBT wafers. This prevents the junction temperature from being too high or too low, which could affect the circuit's control of the motor and consequently the vehicle's operation. The estimated junction temperature is then transmitted to the MCU chip. The MCU chip controls the drive power switching circuit based on the estimated junction temperature, adjusting the power supply to ensure the junction temperature of the SiC and IGBT wafers remains stable, thereby improving the circuit's output stability.

[0011] Preferably, the current sampling circuit adopts a current Hall sampling scheme. Current Hall sampling has the advantages of high accuracy, wide measurement range and fast response. Current Hall sampling is a technology that uses the Hall effect principle to measure current. It mainly consists of a Hall element, a magnetic core and electronic circuits. When current passes through the magnetic core, a magnetic field is generated around it. The magnetic field acts on the Hall element and generates a Hall voltage. By measuring the Hall voltage, the magnitude of the current passing through the magnetic core can be calculated.

[0012] Preferably, the drive power switching circuit comprises: a primary winding, a feedback winding, a multiplexer, and a drive power supply; a feedback winding is provided on the lower side of the primary winding, and the primary winding and the feedback winding form a transformer to improve the stability of the drive power switching circuit; the multiplexer is connected to the MCU chip, and a drive power supply is provided on one side of the multiplexer, and the multiplexer is connected to the drive power supply; the drive power supply is connected to the PWM push-pull circuit, and the drive power supply is divided into drive power supply 1 and drive power supply 2, which are respectively connected to the multiplexer, and both drive power supply 1 and drive power supply 2 are connected to the PWM push-pull circuit. The multiplexer controls the switching circuit by receiving the output signal from the MCU chip, thereby controlling whether drive power supply 1 or drive power supply 2 is connected to the PWM push-pull circuit. By controlling the connection of different drive power supplies to the PWM push-pull circuit, the resistance of the SiC wafer is controlled, the current through the SiC wafer is adjusted, and the junction temperature of the SiC wafer is changed.

[0013] Preferably, the drive power switching circuit includes a SiC drive power switching circuit and an IGBT drive power switching circuit; both the SiC drive power switching circuit and the IGBT drive power switching circuit are connected to the MCU chip and the PWM push-pull circuit; the SiC drive power switching circuit adjusts the junction temperature of the SiC wafer by switching the drive power connection; the IGBT drive power switching circuit adjusts the junction temperature of the IGBT wafer by switching the drive power connection; the drive power switching circuit, through the SiC drive power switching circuit and the IGBT drive power switching circuit, ensures the junction temperature of the SiC wafer and the IGBT wafer, thereby ensuring the stable output of the circuit, and through the independent operation of the two circuits... The improved control enhances the range of junction temperature regulation, further improving the stability of circuit output power and ensuring stable motor operation. When the SiC wafer junction temperature is too high or too low, the MCU chip first switches its own drive power supply through the SiC drive power switching circuit. When the switch cannot meet the regulation of the SiC wafer junction temperature, the MCU chip activates the IGBT drive power switching circuit to switch its own drive power supply, thereby adjusting the resistance ratio of the SiC wafer and the IGBT wafer. This changes the current flowing through the SiC wafer and the IGBT wafer, thus regulating the SiC wafer junction temperature and preventing the SiC wafer from overheating due to excessive current, which could lead to overheating and damage to the power module.

[0014] Preferably, the driving power supply adopts a Flyback circuit. The Flyback circuit has the characteristics of simplicity, high efficiency and isolated output. It is a commonly used circuit topology in switching power supplies. Its main function is to convert the input DC voltage into an isolated, high-frequency AC voltage, and then step it down or step it up through a transformer to finally output the required DC voltage.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows: This utility model uses the equivalent series resistance of the SiC wafer and the IGBT wafer respectively through the SiC drive power switching circuit and the IGBT drive power switching circuit to achieve current distribution between the SiC wafer and the IGBT wafer, control the current carried by the SiC wafer, and thus adjust the junction temperature of the SiC wafer and the IGBT wafer, avoiding the problem of the power module being damaged due to excessive current carried by the SiC wafer. Attached Figure Description

[0016] Figure 1 This is the overall diagram of the modulation circuit of this utility model.

[0017] In the picture:

[0018] 1. Hybrid power module; 11. SiC wafer; 12. IGBT wafer;

[0019] 2. PWM push-pull circuit;

[0020] 3. Current sampling and junction temperature estimation module; 31. Current sampling circuit; 32. Junction temperature estimation unit;

[0021] 4. MCU chip;

[0022] 5. Drive power supply switching circuit; 51. Primary winding; 52. Feedback winding; 53. Multiplexer; 54. Drive power supply; 541. Drive power supply No. 1; 542. Drive power supply No. 2; 55. SiC drive power supply switching circuit; 56. IGBT drive power supply switching circuit. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "several" means two or more, unless otherwise explicitly specified.

[0025] Motor controllers often use hybrid power modules of SiC and IGBT as output devices. SiC power modules can improve the power level of the motor controller and reduce its losses, thereby improving the efficiency of the motor controller and thus increasing the driving range.

[0026] During the production of SiC power modules, the manufacturing process of SiC wafers is difficult. Dislocations, microtubes, and uneven doping and thickness during epitaxial growth in SiC wafers can lead to a decline in electrical performance, resulting in a low yield rate and high production cost of SiC wafers. In order to reduce the cost of hybrid power modules of SiC and IGBTs, the use of SiC wafers is reduced to lower production costs. However, if there are too few SiC wafers, the current shared by the SiC wafers will be too large, which will cause the entire current area of ​​the power module to be affected, resulting in damage to the entire power module.

[0027] like Figure 1As shown, a steady-state current distribution ratio modulation circuit for a SiC-IGBT hybrid power module includes a hybrid power module 1, a PWM push-pull circuit 2, a current sampling and junction temperature estimation module 3, an MCU chip 4, and a drive power switching circuit 5. The hybrid power module 1 is connected to the PWM push-pull circuit 2, which drives the hybrid power module 1 by receiving and amplifying PWM signals. The hybrid power module 1 has a SiC wafer 11 and an IGBT wafer 12. The hybrid power module 1 is connected to the current sampling and junction temperature estimation module 3. The current sampling and junction temperature estimation module 3 is connected to the MCU chip 4. The MCU chip 4 is connected to the drive power switching circuit 5. The drive power switching circuit 5 is connected to the PWM push-pull circuit 2 and is used to adjust the junction temperature of the SiC wafer 11 and the IGBT wafer 12.

[0028] Specifically, the PWM push-pull circuit 2 amplifies the PWM signal to drive the hybrid power module 1, which in turn drives the SiC wafer and IGBT wafer on the hybrid power module. The SiC wafer and IGBT wafer work complementaryly to ensure stable circuit operation. Simultaneously, the mixed use of SiC wafer 11 and IGBT wafer 12 reduces the SiC wafer 11 used by the power module, thereby reducing production costs. The current sampling and junction temperature estimation module 3 samples the current flowing through the hybrid power module 1 in real time and estimates the junction temperature of the SiC wafer 11 and IGBT wafer 12 based on the current magnitude. The current sampling and junction temperature estimation module 3 transmits the estimated junction temperature results of SiC wafer 11 and IGBT wafer 12 to MCU chip 4. MCU chip 4 controls the drive power switching circuit 5 according to the junction temperature results estimated by the current sampling and junction temperature estimation module 3, changes the power supply level, and thus changes the equivalent series resistance of SiC wafer 11 and IGBT wafer 12, thereby changing the current flowing through SiC wafer 11 and IGBT wafer 12, thereby controlling the junction temperature of SiC wafer 11 and IGBT wafer 12, and thus avoiding the problem of power module overheating and damage caused by excessive current on SiC wafer 11.

[0029] Preferably, the drive power switching circuit 5 is symmetrically arranged on both sides of the MCU chip 4, which makes the circuit simple and clear, facilitates wiring, reduces wiring distance, improves response speed, and reduces resource consumption.

[0030] In this embodiment, the current sampling circuit and junction temperature estimation module 3 includes a current sampling circuit 31 and a junction temperature estimation unit 32. The current sampling circuit 31 is connected to the hybrid power module 1 and the junction temperature estimation unit 32, respectively, and is used to sample the current flowing through the hybrid power module 1 in real time. The junction temperature estimation unit 32 is connected to the current sampling circuit 31 and the MCU chip 4, respectively, and is used to estimate the junction temperature of the SiC wafer 11 and the IGBT wafer 12 in real time.

[0031] Specifically, the current sampling circuit 31 samples the current flowing through the hybrid power module 1 in real time, facilitating real-time monitoring of the current in the circuit. Simultaneously, the current sampling circuit 31 transmits the sampled current data to the junction temperature estimation unit 32. The junction temperature estimation unit 32 receives the real-time sampling data from the current sampling circuit 31 and calculates the data to estimate the junction temperature of the SiC wafer 11 and the IGBT wafer 12. This prevents the junction temperature of the SiC wafer 11 and IGBT wafer 12 from being too high or too low, which could affect the circuit's control of the motor and consequently the vehicle's operation. The junction temperature estimation unit 32 transmits the estimated junction temperature to the MCU chip 4. The MCU chip 4 controls the drive power switching circuit 5 based on the estimated junction temperature, adjusting the drive power supply to ensure the junction temperature of the SiC wafer 11 and IGBT wafer 12 remains stable, thereby improving the circuit's output stability.

[0032] In this embodiment, the current sampling circuit 31 adopts a current Hall sampling scheme;

[0033] Specifically, current Hall sampling has the advantages of high precision, wide measurement range and fast response. Current Hall sampling is a technology that uses the Hall effect principle to measure current. It mainly consists of a Hall element, a magnetic core and electronic circuitry. When current passes through the magnetic core, a magnetic field is generated around it. The magnetic field acts on the Hall element and generates a Hall voltage. By measuring the Hall voltage, the magnitude of the current passing through the magnetic core can be calculated.

[0034] In this embodiment, the drive power switching circuit 5 comprises: a primary winding 51, a feedback winding 52, a multiplexer 53, and a drive power supply 54; the feedback winding 52 is provided on the lower side of the primary winding 51; the multiplexer 53 is connected to the MCU chip 4, and the drive power supply 54 is provided on one side of the multiplexer 53, and the multiplexer 53 is connected to the drive power supply 54; the drive power supply 54 is connected to the PWM push-pull circuit 2, and the drive power supply 54 is divided into a first drive power supply 541 and a second drive power supply 542, the first drive power supply 541 and the second drive power supply 542 are respectively connected to the multiplexer 53, and both the first drive power supply 541 and the second drive power supply 542 are connected to the PWM push-pull circuit 2;

[0035] Specifically, the primary winding 51 and the feedback winding 52 form a transformer to improve the stability of the drive power switching circuit 5. The multiplexer 53 controls the switching circuit by receiving the output signal of the MCU chip 4, thereby controlling whether drive power supply 1 541 or drive power supply 2 542 is connected to the circuit. By controlling the connection of different drive power supplies 54 to the circuit, the resistance of the SiC wafer 11 is controlled, thereby adjusting the current through the SiC wafer 11 and changing the junction temperature of the SiC wafer 11.

[0036] Preferably, the voltages of drive power supply 541 and drive power supply 542 are different. In this invention, it is assumed that the voltage of drive power supply 541 is greater than the voltage of drive power supply 542.

[0037] In this embodiment, the drive power switching circuit 5 includes a SiC drive power switching circuit 55 and an IGBT drive power switching circuit 56; both the SiC drive power switching circuit 55 and the IGBT drive power switching circuit 56 are connected to the MCU chip 4 and the PWM push-pull circuit 2; the SiC drive power switching circuit 55 achieves the adjustment of the junction temperature of the SiC wafer 11 by switching the drive power 54; the IGBT drive power switching circuit 56 achieves the adjustment of the junction temperature of the IGBT wafer 12 by switching the drive power 54.

[0038] Specifically, the drive power switching circuit 5, through the SiC drive power switching circuit 55 and the IGBT drive power switching circuit 56, ensures the junction temperature of the SiC wafer 11 and the IGBT wafer 12, thereby ensuring stable circuit output. The independent control of the two circuits improves the control range of the junction temperature, further enhancing the stability of the circuit's output power and ensuring stable motor operation. When the junction temperature of the SiC wafer 11 is too high or too low, it first switches its own drive power supply 54 through the SiC drive power switching circuit 55. When the power supply is insufficient to regulate the junction temperature of SiC wafer 11, MCU chip 4 activates IGBT drive power switching circuit 56 to switch its own drive power supply 54, thereby adjusting the resistance ratio of SiC wafer 11 and IGBT wafer 12. This changes the current flowing through SiC wafer 11 and IGBT wafer 12, thus regulating the junction temperature of SiC wafer 11. This ensures the stability of the junction temperature of SiC wafer 11 and prevents SiC wafer 11 from overheating due to excessive current, which could lead to overheating and damage to the power module.

[0039] Preferably, when adjusting the junction temperature of SiC wafer 11, the IGBT drive power switching circuit 56 is initially kept fixed, and only the drive power supply 54 in the SiC drive power switching circuit 55 is switched. When the drive power supply 54 switched by the SiC drive power switching circuit 55 cannot meet the adjustment of the junction temperature of SiC wafer 11, the drive power supply 54 in the IGBT drive power switching circuit 56 is switched, thereby adjusting the resistance distribution ratio of SiC wafer 11 and IGBT wafer 12, changing the current, and thus completing the adjustment of the junction temperature of SiC wafer 11, avoiding excessive current and temperature rise of SiC wafer 11. The reverse is true when it is necessary to adjust IGBT wafer 12.

[0040] The current adjustment formulas for SiC wafer 11 and IGBT wafer 12 are as follows:

[0041]

[0042] Where: Iall is the total circuit current;

[0043] ISiC represents the current in SiC wafer 11; ResrSiC represents the resistance in SiC wafer 11.

[0044] Iigbt represents the current across the IGBT wafer; Resrigbt represents the resistance across the IGBT wafer.

[0045] When the SiC drive power switching circuit 55 switches from drive power supply 1 541 to drive power supply 2 542, the voltage of the drive circuit where SiC wafer 11 is located decreases. According to its output characteristic curve, its on-resistance increases, and the impedance of the circuit where SiC wafer 11 is located increases, while the impedance of the circuit where IGBT wafer 12 is located remains unchanged. Since the total current remains unchanged, the equivalent resistance of SiC wafer 11 increases, which in turn reduces the current allocated to SiC wafer 11, thereby reducing the junction temperature of SiC wafer 11 and preventing SiC wafer 11 from being subjected to excessive current and temperature rise.

[0046] In this embodiment, the driving power supply 54 adopts a Flyback circuit;

[0047] Specifically, the Flyback circuit is characterized by its simplicity, high efficiency, and isolated output. It is a commonly used circuit topology in switching power supplies. Its main function is to convert the input DC voltage into an isolated, high-frequency AC voltage, which is then stepped down or stepped up by a transformer to finally output the required DC voltage.

[0048] Preferably, the isolated output of the Flyback circuit achieves electrical isolation, thereby giving the drive power supply 54 better safety and reliability, and effectively preventing faults in the circuit from affecting other parts.

[0049] Figure 1 The present invention provides a general diagram of the modulation circuit. The PWM push-pull circuit 2 amplifies the PWM signal to drive the hybrid power module 1. The current sampling and junction temperature estimation module 3 samples the current flowing through the hybrid power module 1 and estimates the junction temperatures of the SiC wafer 11 and the IGBT wafer 12. The current sampling and junction temperature estimation module 3 outputs the estimated junction temperature results to the MCU chip 4. The MCU chip 4 controls the drive power switching circuit 5 to switch the drive power supply 54 according to the estimation results. When the junction temperature of the SiC wafer 11 needs to be adjusted, the SiC drive power switching circuit 55 is adjusted. When the junction temperature of the IGBT wafer 12 needs to be adjusted, the IGBT drive power switching circuit 56 is adjusted. After the drive power supply 54 is switched, the equivalent series resistance changes, thereby realigning the current flowing into the SiC wafer 11 and the IGBT wafer 12 to ensure the stability of the current carried by the SiC wafer 11, thus realizing the adjustment of the junction temperature of the SiC wafer 11 and the IGBT wafer 12.

[0050] In the use of the SiC-IGBT hybrid power module steady-state current distribution ratio modulation circuit of this utility model, the modulation circuit is first powered on at low voltage, and the MCU chip 4 enters standby mode. Then, a drive command is sent, and the MCU chip 4 enters the drive state. The MCU chip 4 outputs according to the current magnitude. At this time, the SiC drive power switching circuit 55 and the IGBT drive power switching circuit 56 are both connected to their respective No. 1 drive power supply 541. The current sampling and junction temperature estimation module 3 collects the current magnitude and estimates the junction temperature of the SiC wafer 11 and the IGBT wafer 12. The current sampling and junction temperature estimation module 3 transmits the estimation result to the MCU chip 4. The MCU chip 4 compares the estimated junction temperature with the set junction temperature. Assuming the set junction temperature is X, when it finds that the estimated junction temperature of the SiC wafer 11 is greater than +5℃, the MCU chip 4 issues a command. The signal to the SiC drive power switching circuit 55 is sent to the multiplexer 53, which disconnects drive power supply 1 541 and connects drive power supply 2 542. At this time, the impedance of the circuit containing SiC wafer 11 increases, the current through SiC wafer 11 decreases, and the junction temperature of SiC wafer 11 decreases. When the junction temperature of SiC wafer 11 is less than X-5℃, the signal is sent to the multiplexer 53. Conversely, drive power supply 2 542 is disconnected and drive power supply 1 541 is connected. The impedance of the circuit containing SiC wafer 11 decreases, the current through SiC wafer 11 increases, and the junction temperature of SiC wafer 11 increases. If the SiC drive power switching circuit 55 cannot meet the junction temperature regulation by switching drive power supply 54, the MCU chip 4 controls the IGBT drive power switching circuit 56 to switch its own drive power supply 54 and adjust the resistance distribution ratio to meet the junction temperature regulation of SiC wafer 11.

[0051] The junction temperature regulation principle of IGBT wafer 12 is the same as above.

[0052] 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. A steady-state current distribution ratio modulation circuit for a SiC-IGBT hybrid power module, characterized in that: Includes a hybrid power module (1), a PWM push-pull circuit (2), a current sampling and junction temperature estimation module (3), an MCU chip (4), and a drive power switching circuit (5). The hybrid power module (1) is connected to the PWM push-pull circuit (2); The PWM push-pull circuit (2) drives the hybrid power module (1) by receiving and amplifying the PWM signal. The hybrid power module (1) is provided with a SiC wafer (11) and an IGBT wafer (12); the hybrid power module (1) is connected to the current sampling and junction temperature estimation module (3); The current sampling and junction temperature estimation module (3) is connected to the MCU chip (4); The MCU chip (4) is connected to the drive power switching circuit (5); The drive power switching circuit (5) is connected to the PWM push-pull circuit (2). The drive power switching circuit (5) is used to adjust the steady-state current distribution of the SiC wafer (11) and the IGBT wafer (12) and thus adjust the junction temperature.

2. The modulation circuit according to claim 1, characterized in that: The current sampling and junction temperature estimation module (3) includes a current sampling circuit (31) and a junction temperature estimation unit (32). The current sampling circuit (31) is connected to the hybrid power module (1) and the junction temperature estimation unit (32) respectively. The current sampling circuit (31) is used to sample the current flowing through the hybrid power module (1) in real time. The junction temperature estimation unit (32) is connected to the current sampling circuit (31) and the MCU chip (4) respectively. The junction temperature estimation unit (32) is used to estimate the junction temperature of the SiC wafer (11) and the IGBT wafer (12) in real time.

3. The modulation circuit according to claim 2, characterized in that: The current sampling circuit (31) adopts a current Hall sampling scheme.

4. The modulation circuit according to claim 1, characterized in that: The drive power switching circuit (5) comprises: a primary winding (51), a feedback winding (52), a multiplexer (53), and a drive power supply (54); A feedback winding (52) is provided on the lower side of the primary winding (51). The multiplexer (53) is connected to the MCU chip (4). A drive power supply (54) is provided on one side of the multiplexer (53), and the multiplexer (53) is connected to the drive power supply (54). The driving power supply (54) is connected to the PWM push-pull circuit (2). The driving power supply (54) is divided into a No. 1 driving power supply (541) and a No. 2 driving power supply (542). The No. 1 driving power supply (541) and the No. 2 driving power supply (542) are respectively connected to the multiplexer (53). The No. 1 driving power supply (541) and the No. 2 driving power supply (542) are both connected to the PWM push-pull circuit (2).

5. The modulation circuit according to claim 4, characterized in that: The drive power switching circuit (5) includes a SiC drive power switching circuit (55) and an IGBT drive power switching circuit (56). The SiC drive power switching circuit (55) and the IGBT drive power switching circuit (56) are both connected to the MCU chip (4) and the PWM push-pull circuit (2); The SiC drive power switching circuit (55) adjusts the junction temperature of the SiC wafer (11) by switching the drive power (54); The IGBT drive power switching circuit (56) adjusts the junction temperature of the IGBT wafer (12) by switching the drive power supply (54).

6. The modulation circuit according to claim 4, characterized in that: The drive power supply (54) adopts a Flyback circuit.

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