Driving circuit with silicon carbide modules connected in parallel

Abstract

The invention discloses a driving circuit with silicon carbide modules connected in parallel. The driving circuit comprises a microcontroller MCU used for outputting a PWM control signal; the first driving chip and the second driving chip are respectively used for receiving the same path of PWM signals output by the MCU; the first isolation driving power supply and the second isolation driving power supply respectively supply power to the first driving chip and the second driving chip; the first silicon carbide module and the second silicon carbide module are respectively connected with the first driving chip and the second driving chip; a first driving resistor is arranged between the first driving chip and the first silicon carbide module, and a second driving resistor is arranged between the second driving chip and the second silicon carbide module. The first driving resistor and the second driving resistor are used for adjusting the switching speed so as to achieve synchronous switching-on and switching-off. According to the invention, dynamic current sharing of the two silicon carbide modules is ensured.

Description

Technical Field

[0001] This invention relates to the field of drive circuit technology, and more specifically to a drive circuit for parallel silicon carbide modules. Background Technology

[0002] In recent years, the electric vehicle industry has flourished. Consumers' demands for vehicle range and performance are constantly increasing, prompting automakers to seek more efficient motor drive solutions. Traditional silicon-based devices are gradually showing limitations in handling high-power, high-frequency requirements. Silicon carbide devices, with their significant advantages such as higher voltage withstand capability, smaller size, faster switching speed, and lower losses, have become a key force driving innovation in motor drive technology.

[0003] In applications requiring higher drive power, a single silicon carbide module is insufficient to meet the output current demand. In such cases, parallel use of silicon carbide modules becomes an effective solution. However, parallel use of silicon carbide modules presents several challenges, such as: inconsistent drive signal delays, drive voltage fluctuations, and gate crosstalk, which exacerbate dynamic current imbalances, leading to incomplete device conduction or false triggering; asynchronous drive signals; differences in threshold voltage (Vth); inconsistent input capacitance (Ciss); asymmetric parasitic parameters; differences in switching transient current spikes, causing uneven voltage stress and EMI issues; and asymmetrical layout leading to differences in power loop inductance (Lp) and gate loop inductance (Lg), among others. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a driving circuit for parallel silicon carbide modules, which solves the crosstalk problem between the two driving signals in the parallel driving of silicon carbide modules.

[0005] Technical Solution: The present invention provides a parallel drive circuit for silicon carbide modules, comprising: a microcontroller (MCU) for outputting PWM control signals; a first drive chip and a second drive chip, each receiving the same PWM signal output by the MCU; a first isolated drive power supply and a second isolated drive power supply for supplying power to the first drive chip and the second drive chip, respectively; a first silicon carbide module and a second silicon carbide module, respectively connected to the first drive chip and the second drive chip; wherein a first drive resistor is provided between the first drive chip and the first silicon carbide module, and a second drive resistor is provided between the second drive chip and the second silicon carbide module, both used to adjust the switching speed to achieve synchronous turn-on and turn-off.

[0006] Furthermore, the first driver chip and the second driver chip are respectively connected to the short-circuit detection circuit, both of which are used to control the corresponding silicon carbide module to shut down when a short-circuit fault is detected.

[0007] Furthermore, the short-circuit detection circuit includes a diode and resistor network connected to the drain-source of the silicon carbide module and connected to the DESAT pin of the driver chip.

[0008] Furthermore, the first silicon carbide module and the second silicon carbide module are respectively connected to temperature detection circuits, both of which are used to detect the module temperature and determine the current sharing status.

[0009] Furthermore, the temperature detection circuit includes an NTC thermistor inside the silicon carbide module, which is connected to the AIP pin of the driver chip.

[0010] Furthermore, the first and second isolated drive power supplies are push-pull switching power supplies, which convert the low-voltage side power supply into a high-voltage side isolated +15V and -4V drive power supply.

[0011] Furthermore, the first silicon carbide module and the second silicon carbide module are connected in parallel to form any one phase upper or lower bridge in the three-phase six-bridge topology of the motor controller.

[0012] Furthermore, the resistance values ​​of the first driving resistor and the second driving resistor are determined by a double-pulse test to match the switching speed.

[0013] The motor controller described in this invention consists of a drive circuit composed of silicon carbide modules connected in parallel.

[0014] Beneficial Effects: Compared with the prior art, the present invention has the following significant advantages: The two drive chips of the present invention share a single PWM signal, ensuring signal consistency. Simultaneously, the use of separate drive chips and power supplies ensures that the first and second silicon carbide modules do not interfere with each other, guaranteeing dynamic current sharing between the two silicon carbide modules. The two drive chips are equipped with separate short-circuit detection circuits and active clamping circuits, providing more timely and accurate protection in case of silicon carbide module failure. Furthermore, the temperature of both silicon carbide modules is collected, and the degree of current sharing between the two modules can be determined through temperature analysis, preventing thermal failure of the silicon carbide modules. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This invention relates to temperature detection; Figure 3 This invention relates to short-circuit detection; Figure 4 This is the isolated drive power supply of the present invention. Detailed Implementation

[0016] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0017] like Figure 1-3As shown, this embodiment of the invention provides a drive circuit for parallel silicon carbide modules, including: a microcontroller (MCU), The system comprises a first driver chip, a first isolated driver power supply, a first silicon carbide module, a second driver chip, a second isolated driver power supply, and a second silicon carbide module. An MCU is connected to the first and second driver chips to provide PWM (Pulse Width Modulation) signals. The first isolated driver power supply is connected to the first driver chip, the first driver chip is connected to the first silicon carbide module, the second isolated driver power supply is connected to the second driver chip, and the second driver chip is connected to the second silicon carbide module.

[0018] The MCU simultaneously provides PWM control signals to both the first and second driver chips, ensuring the synchronization of the control signals and guaranteeing current sharing between the silicon carbide modules. The driver chips convert the control signals into drive signals, enhancing the driving capability and simultaneously achieving isolation between high and low voltage. A first isolated drive power supply powers the first driver chip, and a second isolated drive power supply powers the second driver module. This independent driver chip and independent power supply mode completely isolates the drive circuits of the first and second silicon carbide modules, resolving crosstalk issues during turn-on and turn-off. Simultaneously, the isolated power supplies isolate the low-voltage side from the high-voltage side, ensuring the safety of the low-voltage side. The first driver chip and the first silicon carbide module are connected via a first drive resistor. Adjusting the resistance values ​​of the first and second drive resistors allows adjustment of the turn-on and turn-off speeds of the first and second silicon carbide modules. This ensures synchronous turn-on or turn-off of the first and second silicon carbide modules, avoiding current sharing problems caused by inconsistent turn-on and turn-off speeds. The resistance values ​​of the first and second drive resistors can be determined by a dual-pulse test. The silicon carbide module is connected to the DESAT (defense and protection) pin of the driver chip via D1, D2, and R1 to form a short-circuit detection circuit. When a short-circuit fault occurs in the silicon carbide module, the drain-source voltage of the silicon carbide module increases, the DESAT (defense and protection) pin is pulled high, and the driver chip detects the short-circuit fault and controls the silicon carbide module to shut down safely.

[0019] The internal NTC of the silicon carbide module is connected to the AIP (Analog Input / Output) pin of the driver chip, forming a silicon carbide module temperature detection circuit with R4. The two driver chips can detect the temperature of the two silicon carbide modules respectively, and the temperature readings can determine the current sharing between the two modules, preventing thermal failure of the silicon carbide modules. The first isolation power supply converts the low-voltage side power supply to the high-voltage side power supply, providing +15V and -4V drive power to the driver chips, while ensuring isolation between the low-voltage and high-voltage sides, guaranteeing the safety of the low-voltage side.

[0020] like Figure 4As shown, the isolated driver power supply includes a power chip, a transformer, MOSFETs Q1 and Q2, diodes D1 and D2, capacitors C1 and C2, and resistors R1 and R2. LV1 provides power to the low-voltage side. The isolated driver power supply converts the low-voltage 15V power supply to the high-voltage +15V and -4V power supplies, which power the driver chip. The isolated driver power supply uses a push-pull switching power supply architecture, but the power supply architecture is not limited to this one.

[0021] This invention employs independent driver chips and power supplies to drive the first and second silicon carbide modules in parallel, ensuring current sharing among the modules and resolving the issue of poor consistency in existing silicon carbide modules. The independent driver chips and power supplies completely isolate the drive circuits of the first and second silicon carbide modules, eliminating mutual interference between the drive signals of the parallel silicon carbide modules. Simultaneously, each silicon carbide module has independent short-circuit detection and temperature detection circuits, providing more timely protection for the parallel modules and preventing damage. The turn-on and turn-off speeds of the first and second silicon carbide modules can be controlled by adjusting the drive resistors, avoiding current sharing problems caused by inconsistent turn-on and turn-off speeds.

Claims

1. A drive circuit for parallel connection of silicon carbide modules, characterized in that, include: The microcontroller (MCU) is used to output PWM control signals; the first driver chip and the second driver chip respectively receive the same PWM signal output by the MCU. The first isolated drive power supply and the second isolated drive power supply provide power to the first drive chip and the second drive chip, respectively. The first silicon carbide module and the second silicon carbide module are respectively connected to the first driver chip and the second driver chip; wherein, a first driving resistor is provided between the first driver chip and the first silicon carbide module, and a second driving resistor is provided between the second driver chip and the second silicon carbide module, both of which are used to adjust the switching speed to achieve synchronous turn-on and turn-off.

2. The driving circuit for parallel connection of silicon carbide modules according to claim 1, characterized in that, The first driver chip and the second driver chip are respectively connected to the short-circuit detection circuit, and are both used to control the corresponding silicon carbide module to shut down when a short-circuit fault is detected.

3. The driving circuit for parallel connection of silicon carbide modules according to claim 2, characterized in that, The short-circuit detection circuit includes a diode and resistor network connected to the drain-source of the silicon carbide module and connected to the DESAT pin of the driver chip.

4. The driving circuit for parallel connection of silicon carbide modules according to claim 1, characterized in that, The first silicon carbide module and the second silicon carbide module are each connected to a temperature detection circuit, which is used to detect the module temperature and determine the current sharing status.

5. The driving circuit for parallel connection of silicon carbide modules according to claim 4, characterized in that, The temperature detection circuit includes an NTC thermistor inside the silicon carbide module, which is connected to the AIP pin of the driver chip.

6. The driving circuit for parallel connection of silicon carbide modules according to claim 1, characterized in that, The first and second isolated drive power supplies are push-pull switching power supplies that convert the low-voltage side power supply into +15V and -4V drive power supplies with high-voltage side isolation.

7. The driving circuit for parallel connection of silicon carbide modules according to claim 1, characterized in that, The first silicon carbide module and the second silicon carbide module are connected in parallel to form any one phase upper or lower bridge in the three-phase six-bridge topology of the motor controller.

8. The driving circuit for parallel connection of silicon carbide modules according to claim 1, characterized in that, The resistance values ​​of the first and second driving resistors are determined by a double-pulse test to match the switching speed.

9. A motor controller, characterized in that, It consists of a drive circuit composed of silicon carbide modules connected in parallel as described in any one of claims 1-8.

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