Power module driving method and device, motor controller and automobile

Abstract

The invention discloses a power module driving method and device, a motor controller and an automobile, and the method comprises the steps: determining the required driving current intensity according to the current bus voltage U0 and the current target request output current I0; and according to the required driving current intensity, the gate driving chip is controlled to drive the power module to work with different driving currents. The driving current intensity is divided into a plurality of grades according to working condition requirements, and the driving current is adjusted according to different grades, so that the driving efficiency of the motor controller can be improved, the heating loss of a power module is reduced, the product cooling performance requirement is improved, and the thermal fatigue cycle life is prolonged.

Description

Technical Field

[0001] The present invention belongs to the field of motor control, and in particular relates to a power module driving method, a device, a motor controller and a car. Background Art

[0002] The market share of new energy electric vehicles is increasing. Based on the survey of gate driver chips, the gate driver chips that drive power modules (IGBT / SIC) on the market currently use fixed drive resistors (Ron+Roff), and the drive current cannot be adjusted. At the same time, due to the peak voltage safety value that the power module can withstand under high voltage and high current conditions, the drive current is usually configured to be small, and the size of the (gate) drive current will affect the switching speed of the switch tube in the power module, thereby affecting the switching loss and the working efficiency of the entire motor controller. In addition, the efficiency loss caused by the unadjustable drive current is mostly used for heat generation, and a large amount of heat generation also has a certain damage to the service life of the motor controller. Summary of the invention

[0003] The purpose of the present invention is to provide a power module driving method, device, motor controller and automobile, so as to adjust the driving current according to the working conditions, improve the driving efficiency and reduce the heat loss of the power module.

[0004] In a first aspect, the present invention provides a power module driving method, comprising: The required driving current intensity is determined according to the current bus voltage U0 and the current target requested output current I0.

[0005] According to the required driving current intensity, the gate driver chip is controlled to drive the power module to work with different driving currents.

[0006] Preferably, according to the required driving current intensity, the gate driver chip is controlled to drive the power module to work with different driving currents as follows: If the required driving current intensity is strong driving, the gate driver chip is controlled to drive the gate driver chip with a preset first driving current I d1 Drive the power module to work.

[0007] If the required driving current intensity is medium driving, the gate driver chip is controlled to drive the gate driver chip with a preset second driving current I d2 Drive the power module to work.

[0008] If the required driving current strength is weak driving, the gate driver chip is controlled to drive the gate driver chip with a preset third driving current I d3 Drive the power module to work.

[0009] Wherein, the preset first driving current I d1is the maximum drive current that the gate driver chip can provide, and the preset second drive current I d2 is a moderate driving current that the gate driver chip can provide. The preset third driving current I d3 is the minimum drive current that the gate driver chip can provide, I d1 >I d2 >I d3 .

[0010] Preferably, according to the current bus voltage U0 and the current target requested output current I0, the required driving current intensity is determined as follows: If condition 1a or condition 1b is met, it is determined that the required driving current intensity is weak driving; wherein condition 1a is: U2≤U0≤U1 and 0≤I0≤I1, and condition 1b is: 0<U0<U2 and I2≤I0≤I1.

[0011] If U3≤U0<U2 and I3≤I0<I2, it is determined that the required driving current intensity is medium driving.

[0012] If condition 2a or condition 2b is met, the required driving current intensity is determined to be a strong drive; wherein condition 2a is: 0<U0<U2 and 0≤I0<I3, and condition 2b is: 0<U0<U3 and I3≤I0<I2.

[0013] Among them, I1 represents the preset overcurrent protection current, I2 represents the preset maximum operating current, I3 represents the preset rated operating current, U1 represents the preset overvoltage protection voltage, U2 represents the preset maximum operating voltage, U3 represents the preset rated operating voltage, I1>I2>I3, U1>U2>U3.

[0014] Preferably, the current bus voltage U0 is obtained by detecting a high-voltage voltage divider detection circuit arranged on a driving board; or the current bus voltage U0 is obtained by detecting the output voltage of the battery pack.

[0015] Preferably, the current target requested output current I0 is obtained by: According to the current speed and the current required torque, the preset speed-torque-current table is queried to obtain the current required current I'; wherein the preset speed-torque-current table is a correspondence table of speed, required torque and required current obtained through calibration.

[0016] Determine whether the current cycle is the first cycle after power-on; if so, take the current demand current I' as the current target requested output current I0; otherwise, take the actual output current I collected by the current sensor as back Compare with the current demand current I' and take the actual output current I backThe larger value of the current demand current I' is used as the current target requested output current I0.

[0017] Preferably, the preset overcurrent protection current I1 has a value range of 950A to 1050A, the preset maximum operating current I2 has a value range of 750A to 850A, and the preset rated operating current I3 has a value range of 450A to 550A.

[0018] Preferably, the preset overvoltage protection voltage U1 has a value range of 510V to 550V, the preset maximum operating voltage U2 has a value range of 400V to 500V, and the preset rated operating voltage U3 has a value range of 330V to 360V.

[0019] In a second aspect, the present invention provides a power module driving device, which includes an MCU and a gate driver chip, the MCU is connected to the gate driver chip, the gate driver chip is connected to the power module, and the MCU controls the gate driver chip to drive the power module to work; the MCU is configured to execute the above-mentioned power module driving method.

[0020] In a third aspect, the present invention provides a motor controller, which includes a power module and the power module driving device.

[0021] In a fourth aspect, the present invention provides a vehicle comprising the above-mentioned motor controller.

[0022] The present invention divides the driving current intensity into multiple levels according to the working conditions, and controls the gate driver chip to drive the power module to work with different driving currents according to the different levels (i.e., adjusts the driving current), thereby improving the driving efficiency of the motor controller and reducing the heat loss of the power module.

[0023] Furthermore, the present invention divides the driving current intensity into three levels of strong drive, medium drive and weak drive according to working conditions to adjust the driving current, thereby improving the driving efficiency of the motor controller by more than 0.5%, while greatly reducing the heat loss of the power module, and significantly improving the product cooling performance requirements and thermal fatigue cycle life. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of a power module driving strategy in an embodiment of the present invention.

[0025] Figure 2 FIG. 4 is a flow chart of a power module driving method in an embodiment of the present invention.

[0026] Figure 3 This is a flow chart for obtaining the current target requested output current I0 in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to enable a more detailed understanding of the features and technical contents of the embodiments of the present invention, the implementation of the embodiments of the present invention is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not intended to limit the embodiments of the present invention.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein are only for the purpose of describing the embodiments of the present invention and are not intended to limit the present invention.

[0029] In the following description, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0030] like Figures 1 to 3 As shown, the power module driving method in the embodiment of the present invention is executed by the MCU, which includes: the step of determining the required driving current intensity according to the current bus voltage U0 and the current target requested output current I0; and the step of controlling the gate driver chip to drive the power module to work with different driving currents according to the required driving current intensity. In some embodiments, it specifically includes: Step 1: Obtain the current bus voltage U0 and the current target requested output current I0, and then execute step 2.

[0031] In some embodiments, the current bus voltage U0 is detected by a high-voltage voltage-dividing detection circuit disposed on the driving board.

[0032] In some embodiments, the current bus voltage U0 can also be obtained by detecting the output voltage of the battery pack.

[0033] In some embodiments, the current target requested output current I0 is obtained by the following method (see Figure 3 ): The first step is to query the preset speed-torque-current table according to the current speed and the current required torque to obtain the current required current I', and then execute the second step. Among them, the preset speed-torque-current table is a corresponding relationship table of the speed, required torque and required current obtained by calibration. The calibration method of the speed-torque-current table belongs to the prior art.

[0034] The second step is to determine whether the current cycle is the first cycle after power-on. If so, execute the third step, otherwise execute the fourth step.

[0035] Step 3: Use the current demand current I' as the current target requested output current I0, and then end.

[0036] Step 4: The actual output current I collected by the current sensor back Compare with the current demand current I' and take I back The larger value of I' is used as the current target to request the output current I0, and then it ends.

[0037] Step 2: Determine whether condition 2a or condition 2b is met. If yes, go to step 3; otherwise, go to step 5.

[0038] Among them, condition 2a is: 0<U0<U2 and 0≤I0<I3, and condition 2b is: 0<U0<U3 and I3≤I0<I2. I2 represents the preset maximum operating current, I3 represents the preset rated operating current, U2 represents the preset maximum operating voltage, U3 represents the preset rated operating voltage, I2>I3, U2>U3.

[0039] In some embodiments, the preset maximum operating current I2 has a value range of 750A to 850A, the preset rated operating current I3 has a value range of 450A to 550A, the preset maximum operating voltage U2 has a value range of 400V to 500V, and the preset rated operating voltage U3 has a value range of 330V to 360V. As an example, I2=800A, I3=500A, U2=450A, and U3=350A.

[0040] Step 3: Determine that the required driving current intensity is a strong driving current, and then execute step 4.

[0041] Step 4: Control the gate driver chip to drive the gate driver with a preset first drive current I d1 The driving power module works and then ends. d1 It is the maximum drive current that the gate driver chip can provide.

[0042] When condition 2a or condition 2b is met, the voltage spike generated by the power module is smaller and the margin from the power module voltage protection value is larger. At this time, the maximum driving current is used for driving, and the switching speed of the switch tube in the power module is faster and the loss is minimized, which can significantly improve the working efficiency of the motor controller, while reducing heat loss and reducing the impact of temperature fatigue on device life.

[0043] Step 5: Determine whether U3≤U0<U2 and I3≤I0<I2. If yes, execute step 6; otherwise, execute step 8.

[0044] Step 6: Determine that the required driving current intensity is medium driving, and then execute step 7.

[0045] Step 7: Control the gate driver chip to drive the gate driver with a preset second drive current I d2The driving power module works and then ends. d2 is the moderate drive current that the gate driver chip can provide, I d2 d1 .

[0046] When U3≤U0<U2 and I3≤I0<I2, the voltage spike generated by the power module still has a certain margin from the voltage protection value of the power module. At this time, a moderate driving current is used for driving. The switching speed of the switch tube in the power module is faster and the loss is smaller, which can significantly improve the working efficiency of the motor controller, while reducing heat loss and reducing the impact of temperature fatigue on device life.

[0047] Step 8: Determine whether condition 1a or condition 1b is met. If yes, go to step 9; otherwise, go to step 11.

[0048] Among them, condition 1a is: U2≤U0≤U1 and 0≤I0≤I1, and condition 1b is: 0<U0<U2 and I2≤I0≤I1. I1 represents a preset overcurrent protection current, U1 represents a preset overvoltage protection voltage, I1>I2, U1>U2.

[0049] In some embodiments, the preset overcurrent protection current I1 has a value range of 950A to 1050A, and the preset overvoltage protection voltage U1 has a value range of 510V to 550V. As an example, I1=1000A, U1=520A.

[0050] Step nine: determine that the required driving current intensity is weak driving, and then execute step ten.

[0051] Step 10: Control the gate driver chip to provide a third drive current I d3 The driving power module works and then ends. d3 is the minimum drive current that the gate driver chip can provide, I d3 d2 I d1 ,I d2 ,I d3 The specific value is determined by the selected gate driver chip model.

[0052] When condition 1a or condition 1b is met, the voltage spike generated by the power module is extremely large. At this time, overvoltage and overcurrent damage are more likely to occur. Therefore, the minimum drive current is used for control to ensure safe emergency shutdown and protect the device.

[0053] Step 11: Determine whether the motor controller has entered a safe mode (no longer actively controlling the output), and then end. ​​

[0054] The power module driving device provided by the embodiment of the present invention comprises an MCU and a gate driver chip, wherein the MCU is connected to the gate driver chip, the gate driver chip is connected to the power module, and the MCU controls the gate driver chip to drive the power module to work. The MCU is configured to execute the above-mentioned power module driving method.

[0055] The motor controller provided by the embodiment of the present invention includes a power module and the power module driving device.

[0056] The automobile provided by the embodiment of the present invention includes the above-mentioned motor controller.

[0057] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A power module driving method, characterized in that: include: Determine the required driving current intensity according to the current bus voltage U0 and the current target requested output current I0; According to the required driving current intensity, the gate driver chip is controlled to drive the power module to work with different driving currents.

2. The power module driving method according to claim 1, characterized in that: According to the required driving current intensity, the gate driver chip is controlled to drive the power module to work with different driving currents as follows: If the required driving current intensity is strong driving, the gate driver chip is controlled to drive the gate driver chip with a preset first driving current I d1 Drive the power module to work; If the required driving current intensity is medium driving, the gate driver chip is controlled to drive the gate driver chip with a preset second driving current I d2 Drive the power module to work; If the required driving current strength is weak driving, the gate driver chip is controlled to drive the gate driver chip with a preset third driving current I d3 Drive the power module to work; Wherein, the preset first driving current I d1 is the maximum drive current that the gate driver chip can provide, and the preset second drive current I d2 is a moderate driving current that the gate driver chip can provide. The preset third driving current I d3 is the minimum drive current that the gate driver chip can provide, I d1 > I d2 > I d3 .

3. The power module driving method according to claim 1, characterized in that: According to the current bus voltage U0 and the current target requested output current I0, the required driving current intensity is determined as follows: If condition 1a or condition 1b is met, it is determined that the required driving current intensity is weak driving; wherein condition 1a is: U2≤U0≤U1 and 0≤I0≤I1, and condition 1b is: 0<U0<U2 and I2≤I0≤I1; If U3≤U0<U2 and I3≤I0<I2, it is determined that the required driving current intensity is medium driving; If condition 2a or condition 2b is met, it is determined that the required driving current intensity is strong driving; wherein condition 2a is: 0<U0<U2 and 0≤I0<I3, and condition 2b is: 0<U0<U3 and I3≤I0<I2; Among them, I1 represents the preset overcurrent protection current, I2 represents the preset maximum operating current, I3 represents the preset rated operating current, U1 represents the preset overvoltage protection voltage, U2 represents the preset maximum operating voltage, U3 represents the preset rated operating voltage, I1> I2> I3, U1> U2> U3.

4. The power module driving method according to claim 3, characterized in that: The current bus voltage U0 is detected by a high voltage voltage dividing detection circuit arranged on the driving board; Alternatively, the current bus voltage U0 is obtained by detecting the output voltage of the battery pack.

5. The power module driving method according to claim 3, characterized in that: The current target requested output current I0 is obtained by: According to the current speed and the current required torque, the preset speed-torque-current table is queried to obtain the current required current I'; wherein the preset speed-torque-current table is a corresponding relationship table of the speed, required torque and required current obtained by calibration; Determine whether the current cycle is the first cycle after power-on; if so, take the current demand current I' as the current target requested output current I0; otherwise, take the actual output current I collected by the current sensor as back Compare with the current demand current I' and take I back The larger value of I' is used as the current target requested output current I0.

6. The power module driving method according to any one of claims 3 to 5, characterized in that: The preset overcurrent protection current I1 has a value range of 950A to 1050A, the preset maximum operating current I2 has a value range of 750A to 850A, and the preset rated operating current I3 has a value range of 450A to 550A.

7. The power module driving method according to any one of claims 3 to 5, characterized in that: The preset overvoltage protection voltage U1 has a value range of 510V to 550V, the preset maximum operating voltage U2 has a value range of 400V to 500V, and the preset rated operating voltage U3 has a value range of 330V to 360V.

8. A power module driving device, comprising an MCU and a gate driver chip, wherein the MCU is connected to the gate driver chip, and the gate driver chip is connected to the power module; characterized in that: The MCU is configured to execute the power module driving method according to any one of claims 1 to 7.

9. A motor controller, comprising a power module, characterized in that: It also includes the power module driving device as claimed in claim 8.

10. An automobile, characterized in that: Comprising a motor controller as claimed in claim 9.

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