NVH suppression device and method for electric vehicle equipped with automatic transmission

Abstract

The present invention discloses an NVH suppression device and method for an electric vehicle equipped with an automatic transmission, wherein the suppression device comprises a drive motor, an automatic transmission, a lubricating hydraulic system, an MCU controller, a TCU controller, a vehicle controller, a CAN bus, a threshold judgment unit and a high-frequency NVH suppression solution unit; the drive motor is connected to the automatic transmission, and the lubricating hydraulic system lubricates the automatic transmission; the MCU controller and the TCU controller are respectively connected to the drive motor and the lubricating hydraulic system; the MCU controller and the TCU controller are respectively connected to the CAN through the threshold judgment unit; the vehicle controller is connected to the CAN bus; the high-frequency NVH suppression solution unit input end is connected to the CAN bus and the threshold judgment unit, and the output end is respectively connected to the MCU controller and the TCU controller. The present invention has a simple structure, can improve the service quality of electric vehicles, avoid the occurrence of high-frequency electromagnetic noise, and greatly optimizes the driving environment of the driver.

Description

Technical Field

[0001] The invention relates to an NVH suppression device and method for an electric vehicle equipped with an automatic transmission. Background Art

[0002] Due to the pursuit of high power density, high torque density, lightweight and miniaturization of drive motors, the electromagnetic noise problem is more prominent, resulting in the largest contribution to the overall noise sound pressure level of the motor. At present, under most steady-state conditions, the NVH characteristics of electric vehicles have achieved good results, and drivers can hardly feel the poor driving comfort. Relevant studies have shown that high-frequency electromagnetic noise contributes the most to the overall noise sound pressure level of the motor, and this type of electromagnetic noise will increase significantly with the increase of load. Especially under certain harsh working conditions and the driver's greater driving demand, the motor will produce more serious high-frequency noise, which is subjectively felt as "buzzing" high-frequency electromagnetic noise. The engine also has a corresponding noise aggravation effect when accelerating sharply. Being in this environment for a long time will cause the driver to have physiological reactions such as irritability and headache, which seriously affects driving safety. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a low-cost NVH suppression device and method that can reduce the high-frequency electromagnetic noise of the motor and improve the service environment of the electric vehicle and enhance the driving safety of the driver.

[0004] The technical solution adopted by the present invention is: an NVH suppression device for an electric vehicle equipped with an automatic transmission, comprising a drive motor, an automatic transmission, a lubricating hydraulic system, an MCU controller, a TCU controller, a vehicle controller, a CAN bus, a threshold judgment unit and a high-frequency NVH suppression solution unit; the drive motor is connected to the automatic transmission, and the lubricating hydraulic system lubricates the automatic transmission; the MCU controller and the TCU controller are respectively connected to the drive motor and the lubricating hydraulic system; the input end of the high-frequency NVH suppression solution unit, the MCU controller, and the TCU controller are respectively connected to the CAN through the threshold judgment unit; the vehicle controller is connected to the CAN bus; and the output end of the high-frequency NVH suppression solution unit is respectively connected to the MCU controller and the TCU controller.

[0005] A method for suppressing NVH of an electric vehicle equipped with an automatic transmission using the above-mentioned NVH suppression device of an electric vehicle equipped with an automatic transmission comprises the following steps:

[0006] 1) The vehicle controller provides the actual vehicle speed signal at the current moment, the target vehicle speed signal at the next moment, the automatic transmission lubrication flow signal at the current moment, and the automatic transmission lubrication flow signal at the next moment to the CAN bus;

[0007] 2) The threshold judgment unit performs a threshold judgment on the difference between the actual motor speed at the current moment and the target motor speed at the next moment. If the difference between the target motor speed at the next moment and the actual motor speed at the current moment is greater than the target threshold, proceed to the next step; otherwise, return to step 1);

[0008] 3) Turn on the high-frequency NVH suppression solver to intercept the motor target speed signal and automatic transmission lubrication flow signal sent by the vehicle controller at the next moment. The solver corrects the intercepted signal value and sends it to the MCU controller and TCU controller; until the difference between the motor target speed at the next moment and the actual motor speed at the current moment is less than the target threshold, turn off the high-frequency NVH suppression solver, and restore the motor target speed signal and automatic transmission lubrication flow signal directly sent by the vehicle controller at the next moment.

[0009] In the above-mentioned NVH suppression method for electric vehicles equipped with automatic transmissions, the judgment formula of the threshold judgment unit is as follows:

[0010]

[0011] In the formula, v m+1 represents the vehicle speed signal at the m+1th moment, i.e., the target vehicle speed signal at the next moment; v m represents the vehicle speed signal at the mth moment, that is, the actual vehicle speed signal at the current moment; n0 represents the target threshold, a constant; 1000v m+1 i / (120πr) is the motor target speed at the next moment; 1000v m i / (120πr) is the actual motor speed at the current moment; i represents the automatic transmission ratio, and r is the wheel radius;

[0012] Among them, the motor target speed at the next moment is 1000v m+1 i / (120πr) is based on the target vehicle speed signal v at the next moment m+1 The target vehicle speed signal v at the next moment is m+1 It is determined by the driver's accelerator pedal opening: v m+1 =abv max , v max Represents the maximum speed of the vehicle; a represents the driver's accelerator pedal opening, and b represents the conversion correction coefficient between vehicle speed and accelerator pedal opening; the greater the driver's accelerator pedal opening, the higher the vehicle speed and the higher the motor speed.

[0013] In the above-mentioned NVH suppression method for electric vehicles equipped with automatic transmissions, the high-frequency NVH suppression solution unit generates a correction signal n for the motor target speed at the next moment. t m+1 The calculation formula is:

[0014]

[0015] Where n t m+1 is the correction signal of the motor target speed at the next moment; K is the maximum speed of the motor, a constant; x is the correction coefficient, which is an integer in the range of [1, (120πrK) / (1000v m+1 i-1000v m i)];

[0016] The high-frequency NVH suppression solver generates a correction signal Q for the automatic transmission lubrication flow at the next moment. m+1 The calculation formula is:

[0017]

[0018] In the formula, Q m+1 Q is the correction signal of the automatic transmission lubrication flow at the next moment; m is the lubrication flow signal of the automatic transmission at the current moment; Q1 is the minimum lubrication flow of the automatic transmission; p is the flow correction coefficient and p>1.

[0019] Compared with the prior art, the beneficial effect of the present invention is that the present invention uses the difference between the motor target speed at the next moment and the actual motor speed at the current moment as the judgment condition for the sudden acceleration of the whole vehicle, and corrects the motor target speed signal and the automatic transmission lubrication flow signal at the next moment at the expense of part of the power, and then sends them to the MCU controller and the TCU controller. That is, the whole vehicle performs intermediate intervention during sudden acceleration, and reduces the load resistance of the motor and the whole vehicle during the acceleration process to the greatest extent by reducing the motor's target speed signal and the automatic transmission lubrication flow signal, so as to improve the NVH characteristics of the electric vehicle during the dynamic acceleration process. The present invention has a simple structure, can improve the service quality of electric vehicles, avoid the occurrence of high-frequency electromagnetic noise, and better optimize the driving environment of the driver. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of the NVH suppression device of an electric vehicle equipped with an automatic transmission according to the present invention.

[0021] Figure 2 The figure is a flow chart of the NVH suppression method of an electric vehicle equipped with an automatic transmission according to the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings.

[0023] like Figure 1As shown, the NVH suppression device of an electric vehicle equipped with an automatic transmission of the present invention comprises a drive motor 9, an automatic transmission 8, a lubricating hydraulic system 7, an MCU controller 10, a TCU controller 6, a vehicle controller 1, a CAN bus 2, a threshold judgment unit 3, a threshold judgment unit 5 and a high-frequency NVH suppression solution unit 4. The drive motor 9 is connected to the automatic transmission 8, and the automatic transmission 8 is connected to the lubricating hydraulic system 7; the lubricating hydraulic system 7 lubricates the automatic transmission 8. The MCU controller 10 and the TCU controller 6 are respectively connected to the drive motor 9 and the lubricating hydraulic system 7; the input end of the high-frequency NVH suppression solution unit 4, the MCU controller 10, and the TCU controller 6 are respectively connected to the CAN bus 2 through the threshold judgment unit 3. The vehicle controller 1 is connected to the CAN bus 2; the output end of the high-frequency NVH suppression solution unit 4 is respectively connected to the MCU controller 10 and the TCU controller 6.

[0024] When the driver accelerates suddenly, the motor target speed will increase rapidly due to the excessive opening of the accelerator pedal, resulting in a large difference between the motor target speed and the actual speed. In order to quickly keep up with the motor target speed to meet the rapid acceleration requirements, the vehicle will cause its acceleration resistance to increase sharply, which will lead to a significant increase in the motor output power and the motor output drive torque, and produce excessive motor torque response impact, which will cause a significant increase in the load on the motor body and cause a large high-frequency electromagnetic noise. That is, the difference between the actual motor speed at the current moment and the motor target speed at the next moment has an impact on the NVH of electric vehicles.

[0025] A method for suppressing NVH of an electric vehicle equipped with an automatic transmission comprises the following steps:

[0026] 1) The vehicle controller provides the actual vehicle speed signal at the current moment, the target vehicle speed signal at the next moment, the automatic transmission lubrication flow signal at the current moment, and the automatic transmission lubrication flow signal at the next moment to the CAN bus;

[0027] 2) The threshold judgment unit performs a threshold judgment on the difference between the actual motor speed at the current moment and the target motor speed at the next moment. If the difference between the target motor speed at the next moment and the actual motor speed at the current moment is greater than the target threshold, proceed to the next step; otherwise, return to step 1);

[0028] The judgment formula of the threshold judgment unit is as follows:

[0029]

[0030] In the formula, v m+1 represents the vehicle speed signal at the m+1th moment, i.e., the target vehicle speed signal at the next moment; v mrepresents the vehicle speed signal at the mth moment, that is, the actual vehicle speed signal at the current moment; n0 represents the target threshold, a constant; 1000v m+1 i / (120πr) is the motor target speed at the next moment; 1000v m i / (120πr) is the actual motor speed at the current moment; i represents the automatic transmission ratio, and r is the wheel radius.

[0031] Among them, the motor target speed at the next moment is 1000v m+1 i / (120πr) is based on the target vehicle speed signal v at the next moment m+1 The target vehicle speed signal v at the next moment is m+1 It is determined by the driver's accelerator pedal opening: v m+1 =abv max , v max represents the maximum vehicle speed; a represents the driver's accelerator pedal opening, and b represents the conversion correction coefficient between vehicle speed and accelerator pedal opening. The greater the driver's accelerator pedal opening, the higher the vehicle speed and the higher the motor speed.

[0032] 3) Turn on the high-frequency NVH suppression solver to intercept the motor target speed signal and automatic transmission lubrication flow signal sent by the vehicle controller at the next moment. The solver corrects the intercepted signal value and sends it to the MCU controller and TCU controller; until the difference between the motor target speed at the next moment and the actual motor speed at the current moment is less than the target threshold, turn off the high-frequency NVH suppression solver, and restore the motor target speed signal and automatic transmission lubrication flow signal directly sent by the vehicle controller at the next moment.

[0033] The high-frequency NVH suppression solver generates a correction signal n for the motor target speed at the next moment. t m+1 The calculation formula is:

[0034]

[0035] Where n t m+1 is the correction signal of the motor target speed at the next moment; K is the maximum speed of the motor, a constant; x is the correction coefficient, which is an integer in the range of [1, (120πrK) / (1000v m+1 i-1000v m i)];

[0036] The high-frequency NVH suppression solver generates a correction signal Q for the automatic transmission lubrication flow at the next moment. m+1 The calculation formula is:

[0037]

[0038] In the formula, Q m+1 Q is the correction signal of the automatic transmission lubrication flow at the next moment; m is the lubrication flow signal of the automatic transmission at the current moment; Q1 is the minimum lubrication flow of the automatic transmission; p is the flow correction coefficient and p>1.

Claims

1. A method for suppressing NVH of an electric vehicle equipped with an automatic transmission, which is implemented by using an NVH suppression device for an electric vehicle equipped with an automatic transmission. The NVH suppression device for an electric vehicle equipped with an automatic transmission is characterized by: It includes a drive motor, an automatic transmission, a lubricating hydraulic system, an MCU controller, a TCU controller, a vehicle controller, a CAN bus, a threshold judgment unit and a high-frequency NVH suppression solution unit; the drive motor is connected to the automatic transmission, and the lubricating hydraulic system lubricates the automatic transmission; the MCU controller and the TCU controller are respectively connected to the drive motor and the lubricating hydraulic system; the input end of the high-frequency NVH suppression solution unit, the MCU controller, and the TCU controller are respectively connected to the CAN through the threshold judgment unit; the vehicle controller is connected to the CAN bus; the output end of the high-frequency NVH suppression solution unit is respectively connected to the MCU controller and the TCU controller; The following steps are involved: 1) The vehicle controller provides the actual vehicle speed signal at the current moment, the target vehicle speed signal at the next moment, the automatic transmission lubrication flow signal at the current moment, and the automatic transmission lubrication flow signal at the next moment to the CAN bus; 2) The threshold judgment unit performs a threshold judgment on the difference between the current motor actual speed and the next motor target speed. If the difference between the next motor target speed and the current motor actual speed is greater than the target threshold, proceed to the next step; otherwise, return to step 1); The judgment formula of the threshold judgment unit is as follows: ； In the formula, Representative m+ The vehicle speed signal at one moment is the target vehicle speed signal at the next moment; Representative m The vehicle speed signal at a certain moment, that is, the actual vehicle speed signal at the current moment; represents the target threshold, a constant; is the motor target speed at the next moment; is the actual motor speed at the current moment; i represents the automatic transmission ratio, and r is the wheel radius; Among them, the motor target speed at the next moment is According to the target vehicle speed signal at the next moment The target speed signal at the next moment is It is determined by the driver's accelerator pedal opening: , Represents the maximum speed of the vehicle; a Represents the driver's accelerator pedal opening, b Represents the conversion correction coefficient between vehicle speed and accelerator pedal opening. The greater the driver's accelerator pedal opening, the higher the vehicle speed and the higher the motor speed. 3) Turn on the high-frequency NVH suppression solver, intercept the motor target speed signal and automatic transmission lubrication flow signal sent by the vehicle controller at the next moment, and the solver corrects the intercepted signal value and sends it to the MCU controller and TCU controller; until the difference between the motor target speed at the next moment and the actual motor speed at the current moment is less than the target threshold, turn off the high-frequency NVH suppression solver, and restore the motor target speed signal and automatic transmission lubrication flow signal directly sent by the vehicle controller at the next moment; The high-frequency NVH suppression solver generates a correction signal for the motor target speed at the next moment. The calculation formula is: ； In the formula, is the correction signal of the motor target speed at the next moment; K is the maximum speed of the motor, a constant; x is the correction coefficient, which is an integer and has a range of: ; The high-frequency NVH suppression solver generates a correction signal for the automatic transmission lubrication flow at the next moment. The calculation formula is: ； In the formula, A correction signal for the lubrication flow of the automatic transmission at the next moment; It is the lubrication flow signal of the automatic transmission at the current moment; is the minimum lubrication flow rate of the automatic transmission; p is the flow correction coefficient and p>1.

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