A method for active torsional vibration control of a motor drive process

Abstract

The application discloses a motor driving process active torsional vibration control method, which solves the problem that torsional vibration of a transmission system is difficult to quickly reduce caused by sudden change of motor torque in the motor driving process by reconstructing torque of non-co-phase torque superposition and feedback torque based on a two-degree-of-freedom torsional vibration model to jointly constitute motor output torque. The method comprises the following steps: (1) establishing a two-degree-of-freedom torsional vibration model with motor output shaft angle and wheel angle as generalized coordinates; (2) splitting the motor torque into three different phase difference sub-torques and superimposing to obtain motor reconstructed torque; (3) establishing a transfer function of the motor torque and the wheel speed, and calculating the motor feedback torque through the difference between the required wheel speed and the ideal wheel speed; and (4) calculating the motor output torque. The method weakens the torsional vibration of the transmission system through non-co-phase torque superposition, improves the driving smoothness of the whole vehicle, and improves the response accuracy of the required wheel speed of the driving condition through the feedback torque.

Description

Technical Field

[0001] This invention belongs to the field of automotive torsional vibration control technology, specifically a method for active torsional vibration control during motor drive. Background Technology

[0002] Torsional vibration in the powertrain is one of the main sources of automotive noise. Severe torsional vibration can even lead to driveshaft breakage and damage to torsional dampers. Because there are no hydraulic torque converters or torsional dampers between the motor and the wheels, sudden changes in motor torque during motor drive cause a surge in transmission speed, torque oscillations, and longitudinal impact on the vehicle, making the resulting torsional vibration difficult to dissipate quickly. Torsional vibration control during motor drive aims to optimize motor torque to reduce torque oscillations and longitudinal impact, thereby improving the overall driving smoothness of the vehicle and meeting users' demands for high dynamic performance.

[0003] Some existing patents, such as the invention patent with patent number CN 113511211A, propose a torsional vibration control method based on the electric drive system of an electric vehicle. This method obtains the theoretical motor speed without considering the effect of torsional vibration through a motor model. Then, it calculates the difference between this speed and the actual motor speed and multiplies it by an anti-torsional vibration compensation coefficient to obtain the anti-torsional compensation torque that corrects the target motor torque. This torsional vibration correction is real-time, accurate, and can effectively control torsional vibration, further improving the driving smoothness of the entire vehicle. However, this method calculates the anti-torsional vibration compensation torque based on the difference between the ideal motor speed and the actual motor speed, based on the initial target motor torque. When the sudden change in motor torque is large, the correction amount of the compensation torque is limited, and the torsional vibration phenomenon may be difficult to eliminate quickly, affecting the driver's ride comfort. Summary of the Invention

[0004] This invention aims to solve the problem that sudden changes in motor torque during motor drive make it difficult to quickly reduce torsional vibration in the transmission system. It proposes an active torsional vibration control method for motor drive. This method reconstructs the motor torque into three non-co-phase component torques and superimposes them to weaken the torsional vibration of the transmission system. Then, the motor output torque is adjusted through feedback torque to improve the response accuracy to the wheel speed required by driving conditions.

[0005] To solve the above technical problems, the present invention is implemented using the following technical solution:

[0006] An active torsional vibration control method for motor drive process includes the following steps:

[0007] S1: The motor output shaft rotation angle θ m and wheel turning angle θ w Using generalized coordinates, a two-degree-of-freedom torsional vibration model of the transmission system during the motor drive process is established using formula (1);

[0008]

[0009] In the formula, J m —Equivalent moment of inertia of the motor

[0010] J w —Equivalent moment of inertia of a wheel

[0011] T m Motor torque

[0012] T L — Vehicle running resistance torque

[0013] k H --Equivalent stiffness of the drive shaft

[0014] c H --Equivalent damping of the drive shaft

[0015] i0 — Transmission ratio of the main reducer

[0016] S2: The initial motor torque requirement is corrected and smoothed, then it is split into three component torques with specific phase differences and the three component torques are superimposed to obtain the motor reconfiguration torque;

[0017] S3: Establish the transfer function H(s) of motor torque and wheel rotation angle in the Laplace domain, and calculate the motor feedback torque by combining the motor reconfiguration torque, required wheel speed and feedback coefficient shown in formula (2).

[0018] S4: The motor output torque of the active torsional vibration control method for the motor drive process described above. for

[0019]

[0020] In the preferred technical solution, the motor reconfiguration torque calculation process in step S2 is specifically as follows:

[0021] S21: The initial motor torque is gradually corrected using the first-order inertial element in formula (3);

[0022]

[0023] In the formula, K m , τ m -- Identification parameters of a first-order inertial element

[0024] Initial motor torque requirement

[0025] —Motor corrected torque

[0026] S22: The smoothed motor torque is decomposed into three component torques with specific phase differences and then superimposed. Based on the principle of weakening torsional vibration of the system by superimposing non-in-phase signals, the reconfigured motor torque is obtained. for

[0027]

[0028] In the formula, s1 and s2 are the splitting coefficients.

[0029] Δt1, Δt2 — phase delay factors.

[0030] In the preferred technical solution, the motor feedback torque calculation process in step S3 is specifically as follows:

[0031] S31: The motor output shaft rotation angle θ m Motor output shaft speed Wheel turning angle θ w and wheel speed As a state variable, with motor torque T m As a control variable, wheel speed As the observed variable, the state-space equation is established based on the two-degree-of-freedom torsional vibration model shown in formula (1).

[0032]

[0033] In the formula, U = T m ,

[0034]

[0035]

[0036] C = [0 0 0 1], D = 0

[0037] S32: Based on the Laplace transform, the transfer function H(s) of the motor torque and wheel rotation angle in the Laplace domain is established as follows:

[0038]

[0039] S33: Convert the transfer function H(s) in the Laplace domain to the transfer function L in the time domain based on the inverse Laplace transform. -1 [P(s)], combined with the motor reconfiguration torque shown in formula (4), calculate the ideal wheel speed, and use the difference between the actual wheel speed and the ideal wheel speed as the feedback quantity. Multiply this value by the feedback coefficient to obtain the motor feedback torque.

[0040]

[0041] In the formula, K p —Feedback coefficient

[0042] v - Vehicle speed required for driving conditions

[0043] R – Wheel radius.

[0044] Compared with the prior art, the advantages of the present invention are:

[0045] 1. The active torsional vibration control method for motor drive process described in this invention decomposes the motor torque into three component torques with specific phase differences. By superimposing torques with different phases, the torsional vibration of the transmission system is weakened, and the driving smoothness is improved.

[0046] 2. The active torsional vibration control method for motor drive process described in this invention calculates the ideal wheel speed based on a two-degree-of-freedom torsional vibration model, and obtains the feedback torque by the difference between the actual wheel speed and the ideal wheel speed, thereby improving the response accuracy to the vehicle speed required by driving conditions.

[0047] 3. The active torsional vibration control method for motor drive process described in this invention uses the reconstructed torque of superimposed non-phase torques and the feedback torque based on a two-degree-of-freedom torsional vibration model to jointly constitute the motor output torque. This method has important guiding significance for solving the torsional vibration problem in the pure electric mode of hybrid electric vehicles and the electric drive process of electric vehicles. Attached Figure Description

[0048] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0049] Figure 1 This is a flowchart of an active torsional vibration control method for a motor drive process according to the present invention;

[0050] Figure 2 This is a schematic diagram of a two-degree-of-freedom torsional vibration model of the transmission system in the active torsional vibration control method for motor drive process described in this invention;

[0051] Figure 3 This is a schematic diagram of the motor reconfiguration torque calculation process in the active torsional vibration control method for motor drive process described in this invention. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0053] The invention will now be further described with reference to the accompanying drawings.

[0054] See Figure 1 This invention provides an active torsional vibration control method for motor driving process, specifically including the following steps:

[0055] S1: See Figure 2 With the motor output shaft rotation angle θ m and wheel turning angle θ w Using generalized coordinates, a two-degree-of-freedom torsional vibration model of the transmission system during motor drive is established using formula (1);

[0056]

[0057] In the formula, J m —Equivalent moment of inertia of the motor

[0058] J w —Equivalent moment of inertia of a wheel

[0059] T m Motor torque

[0060] T L — Vehicle running resistance torque

[0061] k H --Equivalent stiffness of the drive shaft

[0062] c H --Equivalent damping of the drive shaft

[0063] i0 — Transmission ratio of the main reducer

[0064] S2: The initial motor torque requirement is corrected and smoothed, then it is split into three component torques with specific phase differences and the three component torques are superimposed to obtain the motor reconfiguration torque;

[0065] S3: Establish the transfer function H(s) of motor torque and wheel rotation angle in the Laplace domain, and calculate the motor feedback torque by combining the motor reconfiguration torque, required wheel speed and feedback coefficient shown in formula (2).

[0066] S4: The motor output torque of the active torsional vibration control method for the motor drive process described above. for

[0067]

[0068] See Figure 3 The specific process for calculating the motor reconfiguration torque in step S2 is as follows:

[0069] S21: The initial motor torque is gradually corrected using the first-order inertial element in formula (2);

[0070]

[0071] In the formula, K m , τ m -- Identification parameters of a first-order inertial element

[0072] Initial motor torque requirement

[0073] —Motor corrected torque

[0074] S22: The smoothed motor torque is decomposed into three component torques with specific phase differences and then superimposed. Based on the principle of weakening torsional vibration of the system by superimposing non-in-phase signals, the reconfigured motor torque is obtained. for

[0075]

[0076] In the formula, s1 and s2 are the splitting coefficients.

[0077] Δt1, Δt2 — phase delay factors.

[0078] The specific process for calculating the motor feedback torque in step S3 is as follows:

[0079] S31: The motor output shaft rotation angle θ m Motor output shaft speed Wheel turning angle θ w and wheel speed As a state variable, with motor torque T m As a control variable, wheel speed As the observed variable, the state-space equation is established based on the two-degree-of-freedom torsional vibration model shown in formula (1).

[0080]

[0081] In the formula, U = T m ,

[0082]

[0083]

[0084] C = [0 0 0 1], D = 0

[0085] S32: Based on the Laplace transform, the transfer function H(s) of the motor torque and wheel rotation angle in the Laplace domain is established as follows:

[0086]

[0087] S33: Convert the transfer function H(s) in the Laplace domain to the transfer function L in the time domain based on the inverse Laplace transform. -1 [P(s)], combined with the motor reconfiguration torque shown in formula (4), calculate the ideal wheel speed. The difference between the required wheel speed under driving conditions and the ideal wheel speed is used as the feedback quantity, multiplied by the feedback coefficient, to obtain the motor feedback torque.

[0088]

[0089] In the formula, K p —Feedback coefficient

[0090] v - Vehicle speed required for driving conditions

[0091] R – Wheel radius.

[0092] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for active torsional vibration control during motor drive, characterized in that, Includes the following steps: S1: Rotation angle of the motor output shaft and wheel angle Using generalized coordinates, a two-degree-of-freedom torsional vibration model of the transmission system during the motor drive process is established using formula (1); （1） In the formula, J m —Equivalent moment of inertia of the motor J w —Equivalent moment of inertia of a wheel T m Motor torque T L — Vehicle running resistance torque k H --Equivalent stiffness of the drive shaft c H --Equivalent damping of the drive shaft i0 — Transmission ratio of the main reducer S2: The initial motor torque requirement is smoothed and then divided into three component torques with specific phase differences. These three component torques are then superimposed to obtain the motor reconfigured torque. ; S3: Establish the transfer function of motor torque and wheel rotation angle in the Laplace domain. The motor feedback torque is calculated by combining the motor reconfiguration torque, the required wheel speed, and the feedback coefficient. ; S4: The motor output torque of the active torsional vibration control method for the motor drive process described above. for （2）。

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