A method for oscillation suppression in hybrid transmission mode switching with active motor response

Abstract

This invention discloses a method for suppressing oscillations during mode switching in a hybrid electric vehicle's active response hybrid transmission, applicable to mode switching when the electric motor engages. This invention improves the FOC motor control strategy through an active response oscillation suppressor. When a power mode switching command is issued, the active response module and torque matching module in the active response oscillation suppressor cooperate to ultimately output a reference torque T. * According to the reference torque T * The invention employs FOC (Focus-Oriented Control) for the motor. By actively responding the motor speed to the clutch drive plate speed, the clutch engagement process is made fast and smooth, thereby reducing system oscillations caused by motor engagement. Simultaneously, after the clutch is fully engaged, the motor quickly switches to torque control to provide more power output to the vehicle, thus making the entire mode switching process smooth and controllable, greatly optimizing the driving and riding experience for passengers.

Description

Technical Field

[0001] This invention discloses a method for oscillation suppression in hybrid transmission mode switching with active motor response, applicable to the field of hybrid power switching technology. Background Technology

[0002] Hybrid electric vehicles (HEVs) are integrated power systems composed of multiple power units. During actual driving, due to the complex and varied driving conditions, the power required for HEV operation also varies considerably. To ensure the vehicle's adaptability to various operating conditions and to guarantee that it always operates within its efficient range, the system switches between different operating modes, and the power source starts or stops depending on the operating mode, achieving different power configurations through various combinations.

[0003] Therefore, the mode transition control problem in hybrid systems is unique to hybrid electric vehicles. During mode transitions, the clutch, engine, and electric motor all participate. Due to the discontinuity of the powertrain characteristics, significant vibrations or torque fluctuations often occur in hybrid systems, sometimes generating large longitudinal shocks that significantly impact the vehicle's forward dynamics. Therefore, ensuring smooth vehicle operation during mode transitions is a crucial objective of hybrid electric vehicle control and has always been a focus of attention, as it involves many complex transient dynamics issues, such as engine starting, electric motor starting, clutch engagement, and brake control. Especially for parallel hybrid electric vehicles, the driving performance during mode transitions is a significant and challenging issue—namely, whether the required power output can be achieved rapidly.

[0004] To address the above issues, numerous scholars both domestically and internationally have conducted extensive research. Examples include: using disturbance observers to facilitate the transition from pure electric mode to hybrid mode, estimating and compensating for disturbances to improve control accuracy, tracking performance, and driving performance; employing efficient mode-switching control methods based on adaptive dual-loop control frameworks to solve the clutch engagement problem in parallel hybrid electric vehicles; utilizing model reference control to coordinate motor torque, engine torque, and clutch torque for smooth transitions; and using multi-model predictive controllers for power management in automatic transmissions for starting cars via dry clutches. However, most research on hybrid electric vehicle mode switching focuses on the transition from pure electric mode to hybrid mode, specifically studying the impact of engine power intervention on system stability and its solutions. Furthermore, the solutions are relatively concentrated on clutch control and vehicle control, lacking solutions to the impact of motor power intervention on system stability. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention proposes a method for oscillation suppression in hybrid transmission mode switching with active motor response. By refining the control down to the motor level, the method solves the oscillation or jerking problem, greatly reducing the burden on the vehicle controller. At the same time, it provides faster response speed, more continuous power output, and a better driving and riding experience for passengers.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0007] A method for suppressing oscillations in a hybrid transmission with active motor response during mode switching includes the following steps:

[0008] Step 1: The vehicle controller sends a power mode switching command to the motor's active response oscillation suppression controller. The power mode switching command includes the mode switching command and the power demand T. ref ;

[0009] Step 2: The active response module of the active response oscillation suppression controller outputs a reference torque T0 to the torque matching module according to the mode switching command, and simultaneously outputs a clutch engagement command. * To the clutch controller;

[0010] Step 3: The torque matching module of the active response oscillation suppression controller matches the power demand T. ref Output reference torque T * ;

[0011] Step 4: Based on the reference torque T * Perform FOC control on the motor.

[0012] Furthermore, the specific method for step two is as follows: Detect the speed ω of the clutch drive plate. c Motor speed ω m With the rotational speed ω of the active disk c The active disk speed ω is used as the reference speed for the active response module. c With motor speed ω m The speed difference Δω is input to the PI controller to obtain the reference torque T1. Simultaneously, the reference torque T1 is delayed to lock its value at this moment, resulting in the reference torque T2. T1, T2, and Δω are input to the judgment program for data analysis, processing, and selection, calculating and outputting the reference torque T0 and the clutch engagement command. * .

[0013] Furthermore, in step two, the judgment procedure analyzes, processes, and selects data. If the speed difference Δω≠0, the reference torque T1 is assigned to the reference torque T0, i.e., T0 = T1, and the clutch engagement command is issued simultaneously. * The value is assigned to 0; if the speed difference Δω = 0, the clutch engagement command is given.* The value is assigned to 1, and the reference torque T2 is assigned to the reference torque T0, i.e., T0 = T2.

[0014] Furthermore, the specific method of step three is as follows: The power demand T of the vehicle controller... ref The bitwise AND operation is performed between the clutch engagement state and the clutch to obtain T. ref * , will T ref * The program analyzes, processes, and selects data from the clutch engagement state and the reference torque T0 output by the active response module, and then calculates and outputs the reference torque T. * .

[0015] Furthermore, the method for data analysis, processing, and selection in step three involves assigning the reference torque T0 to the reference torque T when the clutch engagement state is clutch = 0. * Meanwhile, power demand T ref After the AND operation, it is set to zero, i.e., T. ref * =0, assign the reference torque T0 to T ref * When the clutch is engaged (clutch=1), T will be... ref * Assigned to the reference torque T * .

[0016] Furthermore, the specific method for step four: referencing torque T * The reference current i of the stator dq axis is obtained using the maximum torque-to-current ratio (MPTA). d * i q * The obtained reference current i d * i q * The actual current i of the dq axis in the motor stator q i d The difference is calculated, and after passing through a PI controller, a reference value U for the dq-axis voltage is obtained. q U d The signal is input to SVPWM modulation and finally outputs a specific vector to the converter to perform specific switching actions on the switching transistors and perform FOC control on the motor.

[0017] This invention improves the FOC motor control strategy by adding an active response oscillation suppressor. By actively responding the motor speed to the clutch drive plate speed, the clutch engagement process is made fast and smooth, thereby reducing system oscillations caused by the motor engaging. At the same time, after the clutch is fully engaged, the motor quickly switches to torque control to provide more power output to the vehicle, thus making the entire mode switching process smooth and controllable, greatly optimizing the driving and riding experience of passengers.

[0018] Instruction manual illustrations

[0019] Figure 1 : Overall control block diagram of the method described in this invention;

[0020] Figure 2 : Control block diagram of the active response module of the method described in this invention;

[0021] Figure 3 : Control block diagram of the torque matching module of the method described in this invention;

[0022] Figure 4 MPTA curve of the method described in this invention;

[0023] Figure 5 The system speed tracking performance curve of the method described in this invention;

[0024] Figure 6 The system's fast startup response curve as described in this invention;

[0025] Figure 7 The fast response dq-axis current curve of the system described in this invention;

[0026] Figure 8 The system speed constant torque response curve of the method described in this invention. Detailed Implementation

[0027] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention, based on existing FOC control for permanent magnet synchronous motors and considering the application context of hybrid electric vehicles, proposes a method for suppressing oscillations during hybrid transmission mode switching via active motor response. After the vehicle controller issues a mode switching command, the active response oscillation suppression controller automatically adjusts the motor speed to the target speed, allowing the clutch driving and driven discs to engage quickly at synchronous speed, simplifying the engagement process. Upon engagement, the motor rapidly switches to torque control, outputting the target torque with reference to the power demand from the vehicle controller, thus achieving rapid power output. This method results in faster overall motor response, better clutch engagement, more continuous power output, and effective suppression or even elimination of oscillations during mode transitions.

[0029] like Figure 1 As shown in the diagram, the overall control block diagram of the method of the present invention, a method for suppressing oscillations in a hybrid transmission mode switching system with active motor response, includes the following steps:

[0030] 1) The vehicle controller issues a power mode switching command:

[0031] When the vehicle is in internal combustion engine power output mode, if the onboard battery has sufficient charge or the load suddenly increases, the vehicle controller can issue a power mode switching command to engage the electric motor, switching the vehicle from internal combustion engine power mode to hybrid power mode. The power mode switching command is divided into two parts and transmitted to the electric motor's active response oscillation suppression controller: the mode switching command and the power demand T. ref .

[0032] 2) The active response module operates, outputting a reference torque T0 to the torque matching module, and simultaneously outputting a clutch engagement command. * To the clutch controller:

[0033] Upon receiving a mode switching command, the active response module of the active response oscillation suppression controller begins operation. For example... Figure 2 As shown, the active response module control block diagram of the method of the present invention utilizes a Hall sensor to detect the speed ω of the driving disc when the clutch disengages. c Using this as the reference speed for the active response module, the Hall sensor obtains the motor speed ω. m The rotational speed ω of the active disk will be... c With motor speed ω mThe speed difference Δω is input to the PI controller, and its output is the reference torque T1. Simultaneously, the reference torque T1 is delayed to lock its value at this moment, resulting in reference torque T2. T1, T2, and Δω are input to the judgment program for data analysis, processing, and selection. If the speed difference Δω exists (i.e., Δω ≠ 0), the motor control mode should prioritize speed control. The PI controller output T1 should be the reference torque T0 for the next stage, i.e., T0 = T1, and T0 is sent to the torque matching module. At this time, the clutch driving plate and driven plate have not yet reached synchronous speed. If the clutch engages, it will cause an impact on the entire vehicle and produce a noticeable jerking sensation. Therefore, the clutch engagement command is sent. * =0, and send it to the clutch controller, the clutch engagement state is disengaged, that is, clutch=0.

[0034] If the speed difference Δω = 0, it means that the driving and driven discs of the clutch have reached synchronous speed, and the clutch engagement command is given. * =1, and send it to the clutch controller. The clutch engagement state is engaged, i.e., clutch=1. At the same time, the motor control should quickly switch to torque control mode after the clutch engagement is confirmed. At this time, the task of the active response module is almost completed. In order to make the switching process of the next module smooth, T2 is used as the reference value for the final output, i.e., T0=T2. At this time, the active response module should output T0 to the torque matching module.

[0035] 3) The torque matching module outputs the final reference torque T. * ;

[0036] like Figure 3 As shown, the torque matching module control block diagram of the method of the present invention is based on the power demand T issued by the vehicle controller. ref This serves as the reference torque for the torque matching module. When the speed difference Δω≠0, the motor speed ω needs to be adjusted during the active response phase. m Rapidly increase to the driving disc speed ω of the clutch c Therefore, motor control primarily focuses on speed control. During this stage, the clutch is engaged (clutch=0), i.e., disengaged, and the power demand T from the vehicle controller is transferred. ref T is obtained by performing an AND operation with the clutch engagement state. ref * At this time T ref * =0. T ref * The clutch engagement state (clutch) and the reference torque T0 output by the active response module are input together into the judgment program for data analysis, processing, and selection. During this stage, the clutch state (clutch = 0), and the power demand (T0) is set to zero after calculation. ref *=0, and finally the reference torque T0 output by the active response module will be used as the reference torque T output by the torque matching module. * That is, T * =T0. To ensure a smooth transition, T0 is assigned to T. ref * This prevents sudden torque changes when the clutch engagement command is issued.

[0037] When the speed difference Δω = 0, the clutch engagement command is given. * =1, the clutch engages rapidly. At this time, the reference torque T0 output by the active response module is assigned the value T2. As mentioned above, T2 is the locked value of T1 after a delay, thus achieving a smooth transition between speed control and torque control. After the clutch is fully engaged, the clutch driving plate, driven plate, and motor output shaft can be regarded as a rigid body, and the clutch engagement state changes to engagement, i.e., clutch = 1. At this time, the power demand T from the vehicle controller... ref T is obtained by performing a bitwise AND operation with the clutch engagement state. ref * , T ref * With T ref Equal. T ref * The clutch engagement state (clutch) and the reference torque T0 output by the active response module are input together into the judgment program. At this time, the clutch engagement state (clutch = 1) and T0 is... ref * =T0=T2; further use T ref * The output reference torque T of the motor active response oscillation suppression controller * That is, T *＝ T ref * And the final output reference torque T * The data is transmitted to the FOC control system to achieve complete control of the motor.

[0038] 4) Enter FOC control;

[0039] Reference torque T * The reference current i of the stator dq axis can be obtained using the maximum torque-to-current ratio (MPTA). d * i q * .

[0040] The electromagnetic torque equation of a permanent magnet synchronous motor is:

[0041] T e =1.5pi q [Ψf +i d (L d -L q (1)

[0042] In the formula, p is the extreme logarithm, Ψ f For permanent magnet flux linkage, L d L q These are the d-axis inductance and q-axis inductance, respectively. The current limiting circle and constant current circle during permanent magnet synchronous motor operation are as follows:

[0043] i d 2 +i q 2 ≤I max 2 (2)

[0044]

[0045] By combining equations (1) and (3), we can obtain T. e / i s Take the first-order partial derivative of the expression:

[0046]

[0047] Substituting equations (1), (2), and (3) into equation (4), we get:

[0048] (L d -L q )i d 2 +i d Ψ f -(L d -L q )i q 2 =0 (5)

[0049] By combining equations (1), (2), (3), and (5), we can obtain the equation for the MPTA current operating point curve:

[0050]

[0051] When the motor is a salient pole type, L d =L q i d =0, its MPTA trajectory is:

[0052]

[0053] Figure 4The figure shows the MPTA curve represented on the dq current plane. It can be seen that the optimal current operating point is fixed for a single torque; therefore, MPTA control can achieve the highest torque output from the motor with minimal current consumption. Figure 1 As shown, the obtained reference current i q * i d * The actual current i of the dq axis in the motor stator q i d The difference is calculated, and after passing through a PI controller, a reference value U for the dq-axis voltage is obtained. q U d It enters SVPWM modulation and finally outputs a specific vector to the converter, performing specific switching actions on the switching transistors, thereby realizing FOC control of the motor.

[0054] The proposed method was modeled and simulated using MATLAB / Simulink. To simulate the uncertainty of the clutch speed, a continuously changing target speed was artificially provided during the simulation, and the speed following performance of the system was tested. The results are as follows. Figure 5 As shown, the system load torque increases at 0.5 seconds to verify the adjustment performance under disturbance conditions. It can be seen that the motor speed and target speed are well-matched. Although there is a slight drop at 0.5 seconds due to the increase in load torque, it is quickly corrected within a very short time with minimal overshoot. This indicates that the system's following performance is quite ideal.

[0055] Figure 6 The image shows the system's rapid startup response. The target rotational speed is set to 3000 r / min. Figure 6 -b) As can be seen, the system achieves a rapid speed response in a short period of time. The final speed and torque curves are very smooth. Of course, as the speed of the clutch drive plate changes, the reference speed also changes, and the system's following performance has changed from... Figure 5 Confirmed.

[0056] Figure 7 The dq-axis current curves are shown under fast system response. It can be seen that the decoupling effect of the dq-axis current is quite ideal, especially during the initial startup phase. q Rapid ascent to provide sufficient torque, while i d It rises rapidly in the negative direction to adjust the permanent magnet flux linkage for rapid motor start-up. Once the target speed is reached, i d i q The system stabilizes, allowing the motor to run smoothly.

[0057] To verify the torque response speed and performance after clutch engagement, a torque response test was conducted on the system at a constant speed. The results are as follows: Figure 8As shown. Figure 8 -b) is the motor speed, which is set to a constant 300 r / min here. Figure 8 -a) shows the torque response curve. As can be seen, with a fixed speed, the motor output torque response is very rapid after the reference torque is changed. The rise time is basically controlled at around 0.002 seconds. In actual applications, the time may be slightly longer, but it is sufficient to provide the vehicle with the maximum torque within the allowable time, thereby achieving stronger power output.

[0058] The present invention has been described in detail through examples; however, those skilled in the art should understand that the above examples are merely illustrative and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A method for suppressing oscillations in a hybrid transmission mode switching system with active motor response, characterized in that, Includes the following steps: Step 1: The vehicle controller sends a power mode switching command to the motor's active response oscillation suppression controller. The power mode switching command includes the mode switching command and the power demand T. ref ; Step 2: The active response module of the active response oscillation suppression controller outputs a reference torque T0 to the torque matching module according to the mode switching command, and simultaneously outputs a clutch engagement command. * To the clutch controller; specifically: detect the clutch drive plate speed ω c Motor speed ω m With the active disk rotation speed ω c The active disk speed ω is used as the reference speed for the active response module. c With motor speed ω m The speed difference Δω is input to the PI controller to obtain the reference torque T1. Simultaneously, the reference torque T1 is delayed to lock its value at this moment, resulting in the reference torque T2. T1, T2, and Δω are input to the judgment program for data analysis, processing, and selection, calculating and outputting the reference torque T0 and the clutch engagement command. * ; Step 3: The torque matching module of the active response oscillation suppression controller matches the power demand T. ref Output reference torque T * Specifically, this involves adjusting the power demand T of the vehicle controller. ref The bitwise AND operation is performed between the clutch engagement state and the clutch to obtain T. ref * , will T ref * The program analyzes, processes, and selects data from the clutch engagement state and the reference torque T0 output by the active response module, and then calculates and outputs the reference torque T. * ; Step 4: Based on the reference torque T * Perform FOC control on the motor.

2. The oscillation suppression method for motor-driven active response hybrid transmission mode switching according to claim 1, characterized in that, The method for analyzing, processing, and selecting data in step two involves assigning the reference torque T1 to the reference torque T0 if the speed difference Δω≠0, i.e., T0=T1, and simultaneously issuing the clutch engagement command. * The value is assigned to 0; if the speed difference Δω=0, the clutch engagement command is given. * The value is assigned to 1, and the reference torque T2 is assigned to the reference torque T0, that is, T0=T2.

3. The oscillation suppression method for motor-driven active response hybrid transmission mode switching according to claim 1, characterized in that, The method for data analysis, processing, and selection in step three involves assigning the reference torque T0 to the reference torque T when the clutch engagement state is clutch=0. * Meanwhile, power demand T ref After the AND operation, it is set to zero, i.e., T. ref * =0, assign the reference torque T0 to T ref * When the clutch is engaged (clutch=1), T will... ref * Assigned to the reference torque T * .

4. The oscillation suppression method for motor-driven active response hybrid transmission mode switching according to claim 1, characterized in that, The specific method for step four: reference torque T * The reference current i of the stator dq axis is obtained using the maximum torque-to-current ratio (MPTA). d * i q * The obtained reference current i q * i d * The actual current i of the dq axis in the motor stator q i d The difference is calculated, and after passing through a PI controller, a reference value U for the dq-axis voltage is obtained. q U d The signal is input to SVPWM modulation and finally outputs a specific vector to the converter to perform specific switching actions on the switching transistors and perform FOC control on the motor.

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