Power module service life monitoring device and method, motor controller and vehicle

Abstract

The invention relates to a power module service life monitoring device and method, a motor controller and a vehicle. The power module service life monitoring device comprises an input power supply, a driving power supply unit, a power switch unit, a ripple extraction and amplification unit, a temperature acquisition unit and an MCU controller. The driving power supply unit is used for providing voltage required by driving for the power switch unit; the power switch unit is used for realizing on-off control of the high-voltage circuit; the ripple extraction and amplification unit comprises a ripple extraction element, a signal amplification circuit and a load element; the ripple extraction element is used for extracting a ripple signal from an input power supply; the signal amplification circuit is used for amplifying the ripple signal; the load element is used for converting the amplified ripple signal into a collectable physical signal; the temperature acquisition unit is used for acquiring a temperature signal generated by the load element; and the MCU controller is used for receiving the signal of the temperature acquisition unit and judging whether the power module reaches a life end state or not according to working conditions. The service life of the power module can be accurately estimated.

Description

Technical Field

[0001] This invention relates to the field of motor controller technology, specifically to a power module life monitoring device, method, motor controller, and vehicle. Background Technology

[0002] Current methods for monitoring the lifespan of motor controllers or power modules typically estimate lifespan by monitoring the duration of the Miller plateau and junction temperature of the power module. The advantage of this method is its high real-time performance, which can accurately reflect changes in the power module's own parameters. However, acquiring Miller plateau signals is difficult because the signal duration is short and the oscillation frequency is high, which places high demands on the sampling frequency and bandwidth of the sampling circuit, making its application challenging.

[0003] Therefore, it is necessary to develop a new power module life monitoring device, method, motor controller, and vehicle. Summary of the Invention

[0004] The purpose of this invention is to provide a power module life monitoring device, method, motor controller, and vehicle that can accurately estimate the life of the power module and has a simple circuit.

[0005] In a first aspect, the present invention provides a power module life monitoring device, comprising an input power supply, a drive power supply unit, a power switch unit, a ripple extraction and amplification unit, a temperature acquisition unit, and an MCU controller. The input power supply is used to provide initial power to the entire device; The drive power supply unit is used to convert the initial power supply voltage into a voltage that is adapted to the driving requirements of the power switching unit; The power switching unit is used to control the on / off state of the high-voltage circuit; The ripple extraction and amplification unit includes a ripple extraction element, a signal amplification circuit, and a load element; the ripple extraction element is used to extract ripple signals from the input power supply; the signal amplification circuit is used to amplify the extracted ripple signals; and the load element is used to convert the amplified ripple signals into collectable physical signals. The temperature acquisition unit is used to acquire the temperature signal generated by the load element and the temperature signal of the environment. The MCU controller is used to receive signals from the temperature acquisition unit and, in conjunction with the operating conditions, determine whether the power module has reached the end of its lifespan.

[0006] Optionally, the input power supply is a 12V DC power supply, and a supporting capacitor C1 for filtering is connected in series. The series supporting capacitor C1 filters the input power supply, effectively suppressing noise interference in the power supply, reducing the impact of power supply noise on subsequent drive power supply units, temperature acquisition units, etc., and improving the overall stability of the device.

[0007] Optionally, the drive power supply unit is connected to the output terminal of the input power supply and is used to convert the input power supply voltage into a power supply voltage that is compatible with the drive chip in the power switch unit. The output terminal of the drive power supply unit is connected to the power supply terminal of the drive chip in the power switch unit.

[0008] Optionally, the power switching unit includes a driver chipset, a power transistor group, and an auxiliary component group; the driver chipset and the power transistor group are connected in a one-to-one driving manner; the auxiliary component group includes a driving resistor, a filter capacitor, and a pull-down resistor to ensure the stable switching on and off of the power transistor group; the power transistor group is connected to a high-voltage circuit to realize the on / off control of the high-voltage circuit.

[0009] Optionally, the ripple extraction element includes a coupling capacitor C2; the signal amplification circuit includes an operational amplifier U1, resistors R1, R2, R3, and R6, wherein resistors R1 and R2 are voltage divider resistors providing a reference voltage for operational amplifier U1; resistors R3 and R6 are amplification factor resistors used to adjust the signal amplification factor; the load element includes a load resistor R4. The negative input terminal of operational amplifier U1 is connected to the positive terminal of the input power supply via resistor R3 and coupling capacitor C2, and the negative input terminal of operational amplifier U1 is also connected to the output terminal of operational amplifier U1 via resistor R6; the positive input terminal of operational amplifier U1 is connected to VCC via resistor R1, and the positive input terminal of operational amplifier U1 is also grounded via resistor R2; the output terminal of operational amplifier U1 is grounded via resistor R4. The coupling capacitor C2 is used to efficiently extract the ripple signal of the input power supply; the operational amplifier U1, together with the voltage divider resistor and the amplification resistor, realizes the accurate amplification of the ripple signal; the load resistor R4 converts the amplified ripple into an acquireable physical signal, which greatly improves the detectability and acquisition accuracy of the ripple signal.

[0010] Optionally, the temperature acquisition unit includes NTC resistors R5, R11, R12, and R13; one end of resistor R12 is connected to VCC, and the other end of resistor R12 is grounded via NTC resistor R5; one end of resistor R13 is connected to VCC, and the other end of resistor R13 is grounded via NTC resistor R11; NTC resistor R5 is positioned close to the load element and is used to acquire the temperature of the load element; NTC resistor R11 is used to acquire the ambient temperature signal. Utilizing the temperature sensitivity of the NTC resistors and their close proximity to the load element, the temperature signal of the load element can be acquired accurately and at close range, avoiding attenuation or interference during temperature signal transmission, ensuring the accuracy of temperature acquisition, and providing reliable temperature data for subsequent lifespan assessment.

[0011] Optionally, the MCU controller is connected to the connection point of resistor R12 and NTC resistor R5, and the connection point of resistor R13 and NTC resistor R11, respectively, to receive signals from the temperature acquisition unit.

[0012] Secondly, the power module lifespan monitoring method of the present invention employs the power module lifespan monitoring device as described in the present invention, and the method includes the following steps: After the device is powered on, the input power supply provides power to the drive power supply unit, and the drive power supply unit boosts the voltage to provide power to the power switch unit. The ripple extraction element extracts the ripple signal from the input power supply, amplifies the ripple information through the signal amplification circuit, and outputs it to the load element to drive the load element to generate heat. The temperature acquisition unit continuously acquires the temperature of the load element and transmits the temperature signal to the MCU controller; The MCU controller first determines whether the current operating condition meets the preset conditions, which are that the time for which the motor controller or electric drive operates at peak power is greater than a preset time threshold. If not, it continues to wait and collect the temperature signal of the load element. If it meets the conditions, the MCU controller calculates the temperature difference between the ambient temperature and the collected temperature of the load element and compares the temperature difference with a preset temperature change threshold. If the temperature difference is greater than or equal to the preset temperature change threshold, the threshold voltage Vth state of the power module is determined to have reached the end of its lifespan, i.e., the power module's lifespan has ended; if it has not reached the end of its lifespan, the power module is determined to still be in normal lifespan, and the temperature of the load components will continue to be monitored.

[0013] Thirdly, the motor controller of the present invention includes the power module life monitoring device as described in the present invention.

[0014] Fourthly, the vehicle described in this invention employs a motor controller as described in this invention.

[0015] The beneficial effects of this invention are as follows: Based on the core mechanism of power module lifespan decay, namely, with the increase of usage time and gate switching frequency, the gate threshold voltage Vth drifts, the drive resistor value changes, and thus causes characteristic changes in drive power and input power supply ripple. The ripple signal is separated and amplified by the ripple extraction and amplification unit, and then converted into an acquireable temperature signal by the load element, indirectly reflecting the lifespan status of the power module. By adopting a simple hardware architecture and operating condition-related judgment logic, the lifespan of the power module can be accurately estimated and monitored, effectively avoiding false fault triggering. At the same time, it avoids the hardware design of high-voltage circuits, improves the reliability and safety of the motor controller, replaces traditional manual inspection, and greatly improves the timeliness and accuracy of lifespan monitoring. Attached Figure Description

[0016] Figure 1 This is a circuit diagram of the power module life monitoring device described in the embodiments of this application; Figure 2 This is a flowchart of the power module lifespan monitoring method described in the embodiments of this application; Figure 3 This is a schematic block diagram of the motor controller described in the embodiments of this application; Figure 4 This is a schematic diagram of the vehicle described in the application embodiment. Detailed Implementation

[0017] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0018] See Figure 1 As shown in the illustration, this application discloses a power module lifespan monitoring device, including an input power supply, a drive power supply unit, a power switch unit, a ripple extraction and amplification unit, a temperature acquisition unit, and an MCU controller. The input power supply provides initial power to the entire device. The drive power supply unit converts the initial power supply voltage into a voltage suitable for the drive requirements of the power switch unit. The power switch unit controls the on / off state of the high-voltage circuit. The ripple extraction and amplification unit includes a ripple extraction element, a signal amplification circuit, and a load element; the ripple extraction element extracts ripple signals from the input power supply; the signal amplification circuit amplifies the extracted ripple signals; and the load element converts the amplified ripple signals into collectable physical signals. The temperature acquisition unit acquires temperature signals generated by the load element and ambient temperature signals. The MCU controller receives signals from the temperature acquisition unit and, based on the operating conditions, determines whether the power module has reached the end of its lifespan.

[0019] As the usage time and gate switching frequency of the power module increase, its threshold voltage Vth changes. When the increase in threshold voltage Vth reaches 20% (refer to the AQG-324 Dynamic gate stress test standard), the power module is considered to have reached the end of its lifespan. The change in threshold voltage Vth is reflected in the ripple of the input power supply, which is converted into the temperature change of the load element by the ripple extraction and amplification unit, and then indirectly identified by the MCU controller through the temperature signal.

[0020] In one possible embodiment, the input power supply is a 12V DC power supply, and a supporting capacitor C1 for filtering is connected in series.

[0021] In one possible embodiment, the drive power supply unit is connected to the output terminal of the input power supply to convert the 12V DC voltage of the input power supply into a 15V power supply voltage that is compatible with the drive chip in the power switch unit, and the output terminal of the drive power supply unit is connected to the power supply terminal of the drive chip in the power switch unit.

[0022] In one possible embodiment, the core function of the ripple extraction and amplification unit is to extract and amplify the ripple signal on the 12V input power supply, and drive the load element to heat up through the amplified ripple signal, converting the voltage change of the ripple signal into the temperature change of the resistance, so as to avoid the MCU controller from misjudging due to voltage glitches or oscillations in the ripple signal.

[0023] For example, in the ripple extraction and amplification unit, the ripple extraction element includes a coupling capacitor C2; the signal amplification circuit includes an operational amplifier U1, resistors R1, R2, R3, and R6. Resistors R1 and R2 are voltage divider resistors, providing a reference voltage for the operational amplifier U1; resistors R3 and R6 are amplification factor resistors, used to adjust the signal amplification factor; the load element includes a load resistor R4. The negative input terminal of the operational amplifier U1 is connected to the positive terminal of a 12V DC power supply via resistor R3 and coupling capacitor C2. The negative input terminal of the operational amplifier U1 is also connected to the output terminal of the operational amplifier U1 via resistor R6. The positive input terminal of the operational amplifier U1 is connected to VCC via resistor R1, and is also grounded via resistor R2. The output terminal of the operational amplifier U1 is grounded via resistor R4. In one possible embodiment, the drive power supply unit is connected to the output terminal of the input power supply, used to convert the input power supply voltage into a supply voltage compatible with the drive chip in the power switching unit.

[0024] In one possible embodiment, the power switching unit includes a driver chipset, a power transistor group, and an auxiliary component group; the driver chipset and the power transistor group are connected in a one-to-one driving manner; the auxiliary component group includes a driving resistor, a filter capacitor, and a pull-down resistor to ensure the stable turn-on and turn-off of the power transistor group; the power transistor group is connected to a high-voltage circuit to realize the on / off control of the high-voltage circuit.

[0025] For example, the driver chipset includes driver chip one and driver chip two; the power transistor group includes power transistor M1 and power transistor 2; the auxiliary component group includes drive resistor R7, drive resistor R9, filter capacitor C3, filter capacitor C4, pull-down resistor R10 and pull-down resistor R9, with the following connection relationship: The external control signal TC is connected to the signal input pins of both driver chip 1 and driver chip 2 (serving as the control source for two drives). The output of driver chip 1 is connected to the gate of power transistor M1 via resistor R9. The drain of power transistor M1 is connected to the high-voltage positive terminal HV+; the source of power transistor M1 is connected to the drain of power transistor M2. The gate of power transistor M1 is connected to the source of power transistor M1 via filter capacitor C4, and pull-down resistor R10 is connected in parallel with filter capacitor C4. The output of driver chip 2 is connected to the gate of power transistor M2 via resistor R7. The source of power transistor M2 is connected to the high-voltage negative terminal HV-. The gate of power transistor M2 is also connected to the source of power transistor M1 via filter capacitor C3, and pull-down resistor R8 is connected in parallel with filter capacitor C3. The source of power transistor M1 and the drain of power transistor M2 are directly connected, forming a series structure of "upper transistor (M1) + lower transistor (M2)". Figure 1 The Motor in the diagram connects to the three-phase wires of the motor.

[0026] For example, power transistors M1 and M2 are SiC MOS transistors.

[0027] In one possible embodiment, the temperature acquisition unit includes NTC resistors R5, R11, R12, and R13; one end of resistor R12 is connected to VCC, and the other end of resistor R12 is grounded via NTC resistor R5; one end of resistor R13 is connected to VCC, and the other end of resistor R13 is grounded via NTC resistor R11; NTC resistor R5 is positioned close to the load element and is used to acquire the temperature of the load element; NTC resistor R11 is used to acquire the ambient temperature signal. The NTC resistor reflects temperature changes through its own resistance change: the MCU controller receives the electrical signal from the circuit where the NTC resistor is located, converts the analog electrical signal into a digital signal using the built-in AD conversion module, and then deduces the actual temperature of the acquisition point based on the temperature-resistance curve of the NTC resistor. NTC resistor R11 is used to acquire the ambient temperature signal and is placed in a non-heating area.

[0028] In one possible embodiment, the signal input terminal of the MCU controller is connected to the connection point of resistor R12 and NTC resistor R5, and the connection point of resistor R13 and NTC resistor R11, respectively, to receive temperature acquisition signals. Based on the temperature signal of load resistor R4 detected by NTC resistor R5 and the ambient temperature signal detected by NTC resistor R11, the controller determines whether the power module is in normal lifespan condition in conjunction with the operating conditions.

[0029] like Figure 2 As shown in the embodiments of this application, a power module lifespan monitoring method employs the power module lifespan monitoring device as described in the embodiments of this application, and the method includes the following steps: After the device is powered on, the input power supply provides power to the drive power supply unit, and the drive power supply unit boosts the voltage to provide power to the power switch unit.

[0030] The ripple extraction element extracts the ripple signal from the input power supply, amplifies the ripple information through the signal amplification circuit, and outputs it to the load element to drive the load element to generate heat. The temperature acquisition unit continuously acquires the temperature of the load element and transmits the temperature signal to the MCU controller; The MCU controller first determines whether the current operating condition meets the preset conditions. The preset conditions are that the time for which the motor controller or electric drive operates at peak power is greater than a preset time threshold. If not, it continues to wait and collect the temperature signal of the load element. If it meets the conditions, the MCU controller calculates the temperature difference between the ambient temperature and the collected temperature of the load element and compares the temperature difference with the preset temperature change threshold.

[0031] If the temperature difference is greater than or equal to the preset temperature change threshold, the threshold voltage Vth state of the power module is determined to have reached the end of its lifespan, i.e., the power module's lifespan has ended; if it has not reached the end of its lifespan, the power module is determined to still be in normal lifespan, and the temperature of the load components will continue to be monitored.

[0032] As an example, the monitoring method of this application is described in detail below with reference to the circuit: A method for monitoring the lifespan of a power module includes the following steps: S1: After the device is powered on, the 12V input power supply is filtered by the support capacitor C1 and then supplies power to the drive power supply unit. After the drive power supply unit boosts the voltage, it supplies power to drive chip one and drive chip two. Drive power transistors M1 and M2 are turned on and off according to the preset logic.

[0033] S2: The ripple extraction and amplification unit extracts the ripple signal from the 12V input power supply through the coupling capacitor C2, amplifies it through the operational amplifier U1, and outputs it to the load resistor R4, which drives the load resistor R4 to heat up.

[0034] S3: NTC resistor R5 continuously collects the temperature of load resistor R4 and transmits the temperature signal (MCU_NTC) to the MCU controller.

[0035] S4: The MCU controller first determines whether the current operating condition meets the preset conditions: the motor controller or electric drive runs at peak power for more than 8 seconds; if not, it continues to wait and collect the temperature signal; if it meets the conditions, it proceeds to the next step.

[0036] S5: The MCU controller calculates the temperature difference between the ambient temperature and the temperature of the acquired load resistor R4, and compares this temperature difference with a preset temperature change threshold. S6: If the temperature difference is greater than or equal to the preset temperature change threshold, it is determined that the Vth state of the power module has reached the end of its lifespan, that is, the controller's lifespan has ended; if it has not reached the end of its lifespan, it is determined that the power module is still in the normal lifespan state, and the process returns to step S3 to continue monitoring.

[0037] In this embodiment of the application, the reason for setting the operating condition judgment condition in step S4 is that there is thermal resistance and thermal capacitance between the NTC resistor R5 and the load resistor R4, which causes the temperature change of the NTC resistor to be delayed and slow. By limiting the operating condition of the motor controller or electric drive to run at peak power for more than 8 seconds, the misjudgment caused by the insignificant temperature change of the NTC resistor R5 under low power operating conditions and high power but short duration operating conditions is avoided.

[0038] In this embodiment of the application, the amplification factor of the operational amplifier U1 in step S2 is achieved by adjusting the resistance values ​​of the amplification factor resistors R3 and R6. The adjustment target is to increase the rate of change of the ripple signal and ensure that the temperature change of the load resistor R4 is sufficient to be accurately acquired by the NTC resistor R5.

[0039] like Figure 3 As shown in the embodiments of this application, a motor controller includes a power module life monitoring device as described in the embodiments of this application.

[0040] like Figure 4 As shown in the embodiments of this application, a vehicle employs a motor controller as described in the embodiments of this application.

[0041] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A power module lifespan monitoring device, characterized in that, It includes an input power supply, a drive power supply unit, a power switch unit, a ripple extraction and amplification unit, a temperature acquisition unit, and an MCU controller; The input power supply is used to provide initial power to the entire device; The drive power supply unit is used to convert the initial power supply voltage into a voltage that is adapted to the driving requirements of the power switching unit; The power switching unit is used to control the on / off state of the high-voltage circuit; The ripple extraction and amplification unit includes a ripple extraction element, a signal amplification circuit, and a load element; the ripple extraction element is used to extract ripple signals from the input power supply; the signal amplification circuit is used to amplify the extracted ripple signals; and the load element is used to convert the amplified ripple signals into collectable physical signals. The temperature acquisition unit is used to acquire the temperature signal generated by the load element and the ambient temperature signal. The MCU controller is used to receive signals from the temperature acquisition unit and, in conjunction with the operating conditions, determine whether the power module has reached the end of its lifespan.

2. The power module life monitoring device according to claim 1, characterized in that, The input power supply is a 12V DC power supply, and a supporting capacitor C1 for filtering is connected in series.

3. The power module life monitoring device according to claim 1, characterized in that, The drive power supply unit is connected to the output terminal of the input power supply and is used to convert the input power supply voltage into a power supply voltage that is compatible with the drive chip in the power switch unit. The output terminal of the drive power supply unit is connected to the power supply terminal of the drive chip in the power switch unit.

4. The power module life monitoring device according to claim 1, characterized in that, The power switching unit includes a driver chip group, a power transistor group, and an auxiliary component group; the driver chip group and the power transistor group are connected in a one-to-one driving manner; the auxiliary component group includes a driving resistor, a filter capacitor, and a pull-down resistor, which are used to ensure the stable switching on and off of the power transistor group; the power transistor group is connected to the high-voltage circuit to realize the on / off control of the high-voltage circuit.

5. The power module life monitoring device according to claim 1, characterized in that, The ripple extraction element includes a coupling capacitor C2; the signal amplification circuit includes an operational amplifier U1, resistors R1, R2, R3, and R6, wherein resistors R1 and R2 are voltage divider resistors that provide a reference voltage for the operational amplifier U1; resistors R3 and R6 are amplification factor resistors used to adjust the signal amplification factor; the load element includes a load resistor R4. The negative input terminal of the operational amplifier U1 is connected to the positive terminal of the input power supply via resistor R3 and coupling capacitor C2. The negative input terminal of the operational amplifier U1 is also connected to the output terminal of the operational amplifier U1 via resistor R6. The positive input terminal of the operational amplifier U1 is connected to VCC via resistor R1. The positive input terminal of the operational amplifier U1 is also grounded via resistor R2. The output terminal of the operational amplifier U1 is grounded via resistor R4.

6. The power module life monitoring device according to claim 1, characterized in that, The temperature acquisition unit includes NTC resistors R5, R11, R12, and R13; one end of resistor R12 is connected to VCC, and the other end of resistor R12 is grounded via NTC resistor R5; one end of resistor R13 is connected to VCC, and the other end of resistor R13 is grounded via NTC resistor R11; NTC resistor R5 is positioned close to the load element and is used to acquire the temperature of the load element; NTC resistor R11 is used to acquire the ambient temperature signal.

7. The power module life monitoring device according to claim 6, characterized in that, The MCU controller is connected to the connection points of resistor R12 and NTC resistor R5, and resistor R13 and NTC resistor R11, respectively; and receives signals from the temperature acquisition unit.

8. A method for monitoring the lifespan of a power module, characterized in that, The method of using the power module life monitoring device as described in any one of claims 1 to 7 includes the following steps: After the device is powered on, the input power supply provides power to the drive power supply unit, and the drive power supply unit boosts the voltage to provide power to the power switch unit. The ripple extraction element extracts the ripple signal from the input power supply, amplifies the ripple information through the signal amplification circuit, and outputs it to the load element to drive the load element to generate heat. The temperature acquisition unit continuously acquires the temperature of the load element and transmits the temperature signal to the MCU controller; The MCU controller first determines whether the current operating condition meets the preset conditions, which are that the time for which the motor controller or electric drive operates at peak power is greater than a preset time threshold. If not, it continues to wait and collect the temperature signal of the load element. If it meets the conditions, the MCU controller calculates the temperature difference between the ambient temperature and the collected temperature of the load element and compares the temperature difference with a preset temperature change threshold. If the temperature difference is greater than or equal to the preset temperature change threshold, the threshold voltage Vth state of the power module is determined to have reached the end of its lifespan, i.e., the power module's lifespan has ended; if it has not reached the end of its lifespan, the power module is determined to still be in normal lifespan, and the temperature of the load components will continue to be monitored.

9. A motor controller, characterized in that, Includes the power module life monitoring device as described in any one of claims 1 to 7.

10. A vehicle, characterized in that, The motor controller as described in claim 9 is used.

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