A method and device for controlling motor torque to zero for a p2 hybrid vehicle

Abstract

The application discloses a motor torque zero-crossing control method and device for a P2 hybrid vehicle, which can include: judging whether the motor torque is in a zero-crossing working condition; if yes, calculating the initial target torque change rate of the motor at the current time, and calculating the average change rate of the actual motor speed; based on the first correction value, correcting the initial target torque change rate of the motor, obtaining the first duration of the state that the first dynamic average change rate of the actual motor speed is greater than the first preset calibration value and less than the second preset calibration value, obtaining the second duration of the state that the second dynamic average change rate of the actual motor speed is greater than the second preset calibration value, and according to specific conditions, releasing the correction of the initial target torque change rate of the motor until the actual motor torque reaches the target torque of the motor at the current time.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control technology, and in particular to a motor torque zero-crossing control method and device for a P2 hybrid vehicle. Background Art

[0002] P2 hybrid vehicles can be driven by the engine, the motor, or both, i.e., pure electric driving mode, pure oil driving mode, or parallel driving mode. In pure electric mode, when the torque returns to the driving state after, for example, starting or downshifting, the motor will experience a torque increase from zero to the driving torque. In pure electric mode, power is transmitted to the wheel end through mechanical gears. Due to reasons such as the mechanical processing of the gears themselves, there will inevitably be gaps. When the direction of the motor torque changes, the torque will cross zero. The speed fluctuation caused by the motor's torque crossing zero will cause the vehicle's transmission system to knock, causing vibration of the motor and the entire vehicle. The entire vehicle will appear to be shaking, and there will also be a large impact noise, affecting the driving experience. At this time, it is necessary to control the torque of the motor to reduce the impact caused by the torque crossing zero.

[0003] In the existing technology, in order to avoid large impact and vibration when the torque passes through zero, the slope of the torque rise of the motor when it passes through zero is generally limited to avoid large torque and torque change rate when the gears are engaged. That is, by calibrating a fixed zero-crossing target torque and the duration of this torque. However, this technology will cause the time when the torque passes through zero to be longer, resulting in a slower torque response, and the control effect must be tested multiple times according to the actual situation to calibrate the target torque size and duration when the torque passes through zero. For different situations, it may not be appropriate to calibrate the same zero-crossing target torque and zero-crossing time. There are many situations that need to be considered, which increases the calibration test time and cost.

[0004] Therefore, a new motor torque zero-crossing control method suitable for P2 hybrid vehicles is needed. Summary of the Invention

[0005] The present invention provides a method and device for controlling the zero-crossing torque of a motor of a P2 hybrid vehicle, so as to overcome at least one technical problem existing in the prior art.

[0006] According to a first aspect of an embodiment of the present invention, a method for controlling zero-crossing torque of a motor of a P2 hybrid vehicle is provided, comprising:

[0007] receiving a target torque request instruction, and determining whether the motor torque is in a zero-crossing condition based on the motor target torque and the motor actual torque corresponding to the target torque request instruction at a current moment, to obtain a first determination result;

[0008] If the first judgment result is yes, calculating the rate of change of the initial target torque of the motor at the current moment, specifically comprising: obtaining the target torque of the motor at a moment before the current moment, where the time difference between the current moment and the previous moment is a predetermined time step; calculating the difference between the target torque of the motor at the current moment and the target torque of the motor at the previous moment to obtain a target torque difference, and dividing the target torque difference by the predetermined time step to obtain the rate of change of the initial target torque of the motor at the current moment;

[0009] Calculating the difference between the actual speed of the motor between all two adjacent moments in a number of moments before the current moment to obtain a number of differences, and calculating an average value of the number of differences to obtain an average rate of change of the actual speed of the motor, wherein the number of moments includes the current moment;

[0010] If the average change rate of the actual speed of the motor is greater than a preset first calibration value and less than a preset second calibration value, a pre-established calibration table is queried based on the throttle at the current moment and the gear position at the current moment to determine a first correction value for correcting the initial target torque change rate of the motor; the initial target torque change rate of the motor is corrected based on the first correction value to obtain a corrected first target torque change rate, and the actual torque of the motor is adjusted based on the corrected first target torque change rate; as time goes by, the average change rate of the actual speed of the motor is dynamically calculated to obtain a first dynamic average change rate of the actual speed of the motor; and a first duration in which the first dynamic average change rate of the actual speed of the motor remains greater than the preset first calibration value and less than the preset second calibration value is obtained;

[0011] If the first dynamic average change rate of the actual speed of the motor becomes greater than the pre-set second calibration value, the pre-established calibration table is queried based on the throttle at the latest moment and the gear position at the latest moment to determine a second correction value for correcting the initial target torque change rate of the motor, and the initial target torque change rate of the motor is corrected based on the second correction value to obtain a corrected second target torque change rate; the actual torque of the motor is adjusted based on the corrected second target torque change rate; as time progresses, the average change rate of the actual speed of the motor is dynamically calculated to obtain a second dynamic average change rate of the actual speed of the motor, and a second duration in which the second dynamic average change rate of the actual speed of the motor remains greater than the pre-set second calibration value is obtained;

[0012] If any one of the following conditions is met, the correction of the rate of change of the initial target torque of the motor is released until the actual torque of the motor reaches the target torque of the motor at the current moment; the conditions include:

[0013] The first duration is greater than a preset correction time threshold;

[0014] The second duration is greater than the preset correction time threshold;

[0015] The first dynamic average change rate or the second dynamic average change rate is less than a preset change rate threshold, and the change rate threshold is a negative number.

[0016] Preferably, the zero-crossing operating condition includes: the motor target torque changes from negative torque or zero torque to positive torque, or the motor target torque changes from positive torque or zero torque to negative torque.

[0017] Preferably, the time step ranges from 0.005s to 0.015s.

[0018] Preferably, for vehicles of the same model, the method for determining the first calibration value or the second calibration value includes:

[0019] First, the motor torque change at the moment when the motor torque passes through zero is simulated according to the simulation method to obtain the initial calibration value;

[0020] Based on the initial calibration value, a specific calibration is performed for a specific vehicle model during actual vehicle testing to calibrate a calibration value suitable for the specific vehicle model.

[0021] Preferably, the motor target torque at the current moment is calculated based on the formula TH0 / (i1×i0), wherein the symbol TH0 represents the wheel-end target torque, the symbol i1 represents the gear ratio, and the symbol i0 represents the final reduction ratio.

[0022] Preferably, the method for determining the preset correction time threshold includes:

[0023] First, the motor torque change at the moment when the motor torque passes through zero is simulated according to the simulation method to obtain the initial correction time threshold;

[0024] Based on the initial correction time threshold, a specific calibration is performed for a specific vehicle model during actual vehicle testing to calibrate a pre-set correction time threshold suitable for the specific vehicle model.

[0025] According to a second aspect of an embodiment of the present invention, there is provided a motor torque zero-crossing control device for a P2 hybrid vehicle, comprising:

[0026] a zero-crossing condition determination module, configured to receive a target torque request instruction, determine whether the motor torque is in a zero-crossing condition based on the motor target torque and the motor actual torque at a current moment corresponding to the target torque request instruction, and obtain a first determination result;

[0027] a motor initial target torque change rate calculation module, configured to calculate the motor initial target torque change rate at the current moment if the first judgment result is yes, specifically comprising: obtaining the motor target torque at a moment before the current moment, where the time difference between the current moment and the previous moment is a predetermined time step; calculating the difference between the motor target torque at the current moment and the motor target torque at the previous moment to obtain a target torque difference; and dividing the target torque difference by the predetermined time step to obtain the motor initial target torque change rate at the current moment;

[0028] an average rate of change calculation module for the actual motor speed, configured to calculate the difference in the actual motor speed between all two adjacent moments in a number of moments before the current moment, obtain a number of differences, calculate an average value of the number of differences, and obtain an average rate of change of the actual motor speed, wherein the number of moments includes the current moment;

[0029] A first duration measurement module is configured to query a pre-established calibration table based on the throttle at the current moment and the gear position at the current moment to determine a first correction value for correcting the initial target torque change rate of the motor if the average change rate of the actual speed of the motor is greater than a pre-set first calibration value and less than a pre-set second calibration value; correct the initial target torque change rate of the motor based on the first correction value to obtain a corrected first target torque change rate, and adjust the actual torque of the motor based on the corrected first target torque change rate; dynamically calculate the average change rate of the actual speed of the motor as time progresses to obtain a first dynamic average change rate of the actual speed of the motor; and obtain a first duration in which the first dynamic average change rate of the actual speed of the motor remains greater than the pre-set first calibration value and less than the pre-set second calibration value;

[0030] A second duration measurement module is configured to query the pre-established calibration table based on the throttle at the latest moment and the gear position at the latest moment to determine a second correction value for correcting the initial target torque change rate of the motor if the first dynamic average change rate of the actual speed of the motor becomes greater than the pre-set second calibration value; correct the initial target torque change rate of the motor based on the second correction value to obtain a corrected second target torque change rate; adjust the actual torque of the motor based on the corrected second target torque change rate; dynamically calculate the average change rate of the actual speed of the motor over time to obtain a second dynamic average change rate of the actual speed of the motor, and obtain a second duration in which the second dynamic average change rate of the actual speed of the motor remains greater than the pre-set second calibration value;

[0031] The motor initial target torque correction removal module is configured to remove the correction of the motor initial target torque change rate until the motor actual torque reaches the motor target torque at the current moment if any one of the following conditions is met:

[0032] The first duration is greater than a preset correction time threshold;

[0033] The second duration is greater than the preset correction time threshold;

[0034] The first dynamic average change rate or the second dynamic average change rate is less than a preset change rate threshold, and the change rate threshold is a negative number.

[0035] One embodiment of the present specification can achieve at least the following beneficial effects: In this solution, the target torque change rate when the torque passes through zero is corrected based on the motor speed change rate, thereby providing a control method for variable target torque and variable torque holding time to address the problem in the prior art that torque zero crossing control cannot adapt to different situations. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 A flowchart of a motor torque zero-crossing control method for a P2 hybrid vehicle provided in an embodiment of this specification;

[0038] Figure 2 The embodiments of this specification provide corresponding Figure 2 A schematic structural diagram of a motor torque zero-crossing control device for a P2 hybrid vehicle;

[0039] Figure 3 This is a schematic diagram of the effect of a motor torque zero-crossing control method for a P2 hybrid vehicle provided in an embodiment of this specification. DETAILED DESCRIPTION

[0040] To make the purpose, technical solutions, and advantages of one or more embodiments of this specification more clear, the technical solutions of one or more embodiments of this specification will be clearly and completely described below in conjunction with the specific embodiments of this specification and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of one or more embodiments of this specification.

[0041] It should be understood that although the terms first, second, third, etc. may be used in this application document to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other.

[0042] Hybrid vehicles are a type of new energy vehicle. Hybrid vehicles use both an engine and an electric motor to drive the vehicle. P2 hybrid vehicles can be driven by the engine, the electric motor, or both, i.e., pure electric driving mode, pure oil driving mode, and parallel driving mode. In pure electric mode, when the torque returns to the driving state after starting or downshifting, the motor will increase its torque from zero to the driving torque. In pure electric mode, power is transmitted to the wheel end through mechanical gears. Due to the mechanical processing of the gears themselves, there will inevitably be gaps. When the motor changes from no power to providing driving force, the tooth surface changes from a gap state to an engaged state. If the force is too great, it will cause a large impact, which will cause vibration of the motor and the entire vehicle. The entire vehicle will show a relatively shaky performance, and will be accompanied by a large impact noise, affecting the driving experience. At this time, it is necessary to control the torque of the motor to reduce the impact caused by the torque passing through zero.

[0043] In the prior art, in order to avoid large shock and vibration when the torque passes through zero, the slope of the torque rise when the motor passes through zero is generally limited to avoid large torque and torque change rate when the gears are engaged. That is, by calibrating a fixed zero-crossing target torque and the duration of this torque. However, this will cause the torque to pass through zero for a longer time, resulting in a slower torque response, and the control effect must be tested multiple times according to the actual situation. The target torque size and duration when the torque passes through zero are calibrated. For different situations, calibrating the same zero-crossing target torque and zero-crossing time may not be appropriate. There are many situations that need to be considered, which increases the calibration test time and cost. Simply giving a fixed torque zero-crossing target torque and torque duration cannot meet the zero-crossing torque control requirements under different conditions. Moreover, for vehicles with different assembly deviations, the control effect of preventing vibration with the same set of target zero-crossing torque calibration may have deviations.

[0044] In order to solve the defects in the existing technology, this solution provides a motor torque zero-crossing control method for a P2 hybrid vehicle. In this solution, the target torque change rate when the torque crosses zero is corrected according to the motor speed change rate, so as to address the problem that the torque zero-crossing control method in the existing technology cannot adapt to different situations.

[0045] Next, a motor torque zero-crossing control method for a P2 hybrid vehicle provided in an embodiment of the specification will be described in detail with reference to the accompanying drawings.

[0046] Figure 1 This is a flow chart of a method for controlling the zero-crossing torque of a motor of a P2 hybrid vehicle provided in an embodiment of this specification. From a program perspective, the execution body of the flow can be a program installed in the vehicle controller VCU.

[0047] like Figure 1 As shown, the process may include the following steps.

[0048] Step 102: Receive a target torque request instruction, and determine whether the motor torque is in a zero-crossing condition based on the motor target torque and the motor actual torque corresponding to the target torque request instruction at the current moment, to obtain a first determination result.

[0049] In the embodiments of this specification, a target torque request instruction is used to represent an instruction received by the vehicle control unit (VCU) program requesting adjustment of the current motor's actual torque. In real-world scenarios, the vehicle's instantaneous torque demand is primarily controlled by the accelerator pedal. Under unrestricted conditions, a corresponding motor torque is output based on a preset relationship between accelerator pedal opening and torque. However, actual operating conditions are complex and subject to numerous limitations. This requires the vehicle's electronic control system (VCU) to adjust the torque demand in real time based on the vehicle's actual conditions. The motor controller then controls the motor's torque output based on the VCU's requirements to drive the vehicle. One of these complex operating conditions is the transition between positive and negative torque, i.e., the motor torque can cross zero. During this transition, due to the limitations of the transmission system's inherent process technology, which prevents tight coordination, a certain amount of gear play during the transmission process can cause gear collisions and impacts during the positive and negative torque transitions. Since the change from the actual motor torque to the target torque corresponding to the target torque request instruction is a dynamic process, in order to minimize the gear collision impact problem that may occur later, it is necessary to determine in this step whether the motor torque will be in a zero-crossing condition after the motor controller receives the target torque request instruction. The specific judgment method is not specifically limited in this step.

[0050] Step 104: If the first judgment result is yes, the rate of change of the initial target torque of the motor at the current moment is calculated, specifically including: obtaining the target torque of the motor at the previous moment before the current moment, where the time difference between the current moment and the previous moment is a predetermined time step; calculating the difference between the target torque of the motor at the current moment and the target torque of the motor at the previous moment to obtain a target torque difference, and dividing the target torque difference by the predetermined time step to obtain the rate of change of the initial target torque of the motor at the current moment.

[0051] In the embodiments of the present specification, in order to clearly illustrate the scheme, the motor target torque at the current moment can be marked as Tem, and the motor target torque at the previous moment relative to the current moment can be marked as TEmPre, and the motor initial target torque change rate at the current moment can be calculated based on the formula (TEm-TEmPre) / Δt. Wherein, the symbol Δt is used to represent the time difference between the current moment and the previous moment of the current moment. The time difference can be a constant value, and its numerical value may be set according to the specific scenario. This embodiment does not impose specific restrictions. The motor initial target torque change rate at the current moment obtained in this step can be used as the basis for adjusting the torque change rate in subsequent steps.

[0052] Step 106: Calculate the difference in actual motor speed between all two adjacent moments in a number of moments before the current moment to obtain a number of differences, calculate the average value of the number of differences, and obtain the average change rate of the actual motor speed, wherein the number of moments includes the current moment.

[0053] In the embodiment of this specification, in order to clearly explain the operation of this step, the current time can be marked as t current , the several moments before the current moment are marked as t current-1 , t current-2 ,…,t current-i , where parameter i represents the number of moments before the current moment; then t current and t current-1 Take these two adjacent moments as an example, the difference in the actual motor speed between the two adjacent moments is expressed in Nm current -Nm current-1 Calculated, where the symbol Nm current Represents the current time t current The actual motor speed under the symbol Nm current-1 Represents the current time t current The previous moment t current-1 Based on this, the average rate of change of the actual motor speed is calculated by the following formula:

[0054]

[0055] The above formula can be simplified to The symbol Nm current-i Represents the current time t current The actual motor speed at the i-th moment before the current moment, and Δt is the time difference between two adjacent moments. It should be noted that in this step, the specific value of parameter i is used to indicate how many moments before the current moment are included in the calculation range of the average rate of change of the motor's actual speed. Its value can be flexibly set according to the specific situation and is not specifically limited in this step. For example, it can be set to an integer between 3 and 10.

[0056] Step 108: If the average change rate of the actual speed of the motor is greater than a preset first calibration value and less than a preset second calibration value, a pre-established calibration table is queried based on the throttle at the current moment and the gear at the current moment to determine a first correction value for correcting the initial target torque change rate of the motor; the initial target torque change rate of the motor is corrected based on the first correction value to obtain a corrected first target torque change rate, and the actual torque of the motor is adjusted based on the corrected first target torque change rate; as time goes by, the average change rate of the actual speed of the motor is dynamically calculated to obtain a first dynamic average change rate of the actual speed of the motor; and a first duration of time in which the first dynamic average change rate of the actual speed of the motor remains greater than the preset first calibration value and less than the preset second calibration value is obtained.

[0057] It is explained in the previous step 104 that the initial target torque change rate of the motor at the current moment can be used as the basis for adjusting the torque change rate in the subsequent steps. This step 108 and the subsequent step 110 will use the initial target torque change rate of the motor at the current moment as the basis for adjusting the torque change rate. In these two steps, two calibration values ​​are required, namely the first calibration value and the second calibration value, wherein the second calibration value is greater than the first calibration value. A possible calibration value obtaining process will be described later. During specific execution, the initial target torque change rate of the motor at the current moment in step 106 can be compared with the first calibration value. If its numerical value is between the first calibration value and the second calibration value, a pre-established calibration table can be queried based on the throttle at the current moment and the gear position at the current moment to determine the first correction value for correcting the initial target torque change rate of the motor. In order to explain this, as Figure 3As shown, the broken line portion labeled 1 can be expressed as adjusting the actual torque of the motor according to the initial target torque change rate of the motor. The broken line portion 2 between the first dotted line and the second dotted line from left to right in this figure can be understood as adjusting the actual torque of the motor according to the first target torque change rate obtained after correcting the initial target torque change rate of the motor based on the first correction value. The slope of the broken line portion 2 is smaller than the slope of the broken line portion 1, thereby reducing the impact of the torque crossing zero by reducing the rising slope of the positive torque or the falling slope of the negative torque.

[0058] At the same time, the previous step 102 explained that the change from the actual torque of the motor to the target torque corresponding to the target torque request instruction is a dynamic process. The average change rate of the actual speed of the motor based on this step is not fixed based on the value calculated in step 106, but is a process that is dynamically updated over time. That is, for a specific moment after the current moment, when calculating the average change rate of the actual speed of the motor corresponding to the specific moment, the calculation method of the average change rate of the actual speed of the motor corresponding to the current moment in step 106 is used to obtain the actual speed of the motor for several moments before the specific moment, and then calculate the average change rate of the actual speed of the motor corresponding to the specific moment. That is, as time goes by, the average change rate of the actual motor speed corresponding to the latest current moment is a dynamically updated process. In this step, the dynamically updated average change rate of the actual motor speed is marked as the first dynamic average change rate. At the same time, the first duration of the state in which the first dynamic average change rate remains greater than the preset first calibration value and less than the preset second calibration value can be counted. Since the initial target torque change rate of the motor is not continuously corrected based on the first correction value in this scheme, the first duration can be used as a basis for when to cancel the correction of the initial target torque change rate of the motor in subsequent steps.

[0059] Step 110: If the first dynamic average change rate of the actual speed of the motor becomes greater than the pre-set second calibration value, the pre-established calibration table is queried based on the throttle at the latest moment and the gear at the latest moment to determine the second correction value for correcting the initial target torque change rate of the motor, and the initial target torque change rate of the motor is corrected based on the second correction value to obtain a corrected second target torque change rate; the actual torque of the motor is adjusted based on the corrected second target torque change rate; as time goes by, the average change rate of the actual speed of the motor is dynamically calculated to obtain the second dynamic average change rate of the actual speed of the motor, and the second duration of the state in which the second dynamic average change rate of the actual speed of the motor remains greater than the pre-set second calibration value is obtained.

[0060] Step 108 explains that the average rate of change of the actual motor speed corresponding to the latest current moment is a dynamically updated process. Therefore, in this step, when the average rate of change of the actual motor speed corresponding to the latest current moment, that is, the first dynamic average rate of change, begins to become greater than the pre-set second calibration value (the second calibration value is greater than the first calibration value in step 106), the pre-established calibration table can be queried based on the throttle at the latest moment and the gear at the latest moment to determine the second correction value for correcting the initial target torque change rate of the motor. To explain this, as shown in FIG. Figure 3 As shown, the broken line portion labeled 1 previously explained that the actual motor torque is adjusted according to the initial target torque change rate of the motor. The broken line portion 3 between the second and third broken lines shown from left to right in this figure can be understood as the second target torque change rate obtained by correcting the initial target torque change rate of the motor based on the second correction value to adjust the actual motor torque. The slope of broken line portion 3 is less than the slope of broken line portion 2, so that in this step, the impact of torque zero crossing is further reduced by reducing the positive torque rising slope or the negative torque falling slope. Because the average change rate of the actual motor speed corresponding to the latest current moment is greater than the first calibration value and less than the second calibration value in this step, in order to distinguish it from the first dynamic average change rate in step 108, in this step, the average change rate of the actual motor speed corresponding to the latest current moment that is greater than the first calibration value and less than the second calibration value is recorded as the second dynamic average change rate. At the same time, the second dynamic average change rate corresponding to the latest current moment is continuously calculated over time, and the second duration of the second dynamic average change rate remaining greater than the second calibration value can be calculated. Similar to step 108 , since the present solution does not continuously correct the motor's initial target torque change rate based on the second correction value, the second duration can be used as a basis for determining when to stop correcting the motor's initial target torque change rate in subsequent steps.

[0061] Two calibration values ​​are required in the above steps 108 and 110, namely the first calibration value and the second calibration value. In an optional scheme, for vehicles of the same model, the method for determining the first calibration value or the second calibration value may include: first, simulating the change of the motor torque at the moment when the motor torque passes through zero according to a simulation method to obtain an initial calibration value; based on the initial calibration value, performing specific calibration for the specific model of the vehicle during actual vehicle testing to calibrate a calibration value suitable for the specific model.

[0062] Similarly, the first correction value and the second correction value for correcting the initial target torque change rate of the motor are described above, and the first correction value and the second correction value can be obtained by querying a pre-prepared calibration table based on the accelerator at the time to be queried and the gear at the time to be queried. The calibration table can also be determined by first determining the initial value according to the simulation method, and then specifically calibrated for different accelerators and gears during real vehicle testing to obtain calibration values suitable for specific vehicle models.

[0063] Step 112: If any of the following conditions are met, the correction of the initial target torque change rate of the motor is removed until the actual motor torque reaches the motor target torque at the current time; the conditions include:

[0064] The first duration is greater than a pre-set correction time threshold;

[0065] The second duration is greater than the pre-set correction time threshold;

[0066] The first dynamic average change rate or the second dynamic average change rate is less than a pre-set change rate threshold, and the change rate threshold is negative.

[0067] As described above, the present scheme does not continuously correct the initial target torque change rate of the motor based on the first correction value or the second correction value. The scheme in step 112 describes under what conditions the correction of the initial target torque change rate of the motor is removed, so that after the correction of the initial target torque change rate of the motor is removed, the actual motor torque reaches the motor target torque at the current time. The determination method of the pre-set correction time threshold in this step can include: first simulating the motor torque change at the motor torque zero-crossing time according to the simulation method to obtain an initial correction time threshold; based on the initial correction time threshold, the specific vehicle model of the vehicle is specifically calibrated during real vehicle testing to calibrate the final pre-set correction time threshold suitable for the specific vehicle model. Similarly, the pre-set change rate threshold can also be determined based on the simulation and real vehicle testing method, which will not be described here.

[0068] As shown in Figure 3 After the correction of the initial target torque change rate of the motor is removed, the motor torque can change as shown by line segment 4 until it reaches the motor target torque corresponding to the current time in step 102.

[0069] It should be understood that in the method described in one or more embodiments of the present specification, the order of some steps can be adjusted according to actual needs, or some steps can be omitted.

[0070] Figure 1The solution in the present invention amends the target torque change rate when the torque crosses zero based on the speed change rate, and provides a control method with variable target torque and variable torque holding time to address the problem that the torque zero crossing control in the existing technology cannot adapt to different situations.

[0071] based on Figure 1 The present specification also provides some specific implementation plans of the method, which are described below.

[0072] The technical solution provided by the present invention can be applied to torque zero-crossing conditions in different situations, so that in an optional solution, the zero-crossing condition may include: the zero-crossing condition includes: the motor target torque changes from negative torque or zero torque to positive torque, or, the motor target torque changes from positive torque or zero torque to negative torque.

[0073] In an optional solution, the time step Δt ranges from 0.005s to 0.015s.

[0074] In an optional solution, the motor target torque at the current moment is calculated based on the formula TH0 / (i1×i0), where the symbol TH0 represents the wheel-end target torque, the symbol i1 represents the gear ratio, and the symbol i0 represents the final reduction ratio.

[0075] Based on the same idea, the embodiments of this specification also provide a device corresponding to the above method. Figure 2 The embodiments of this specification provide corresponding Figure 1 A schematic diagram of a motor torque zero-crossing control device for a P2 hybrid vehicle. Figure 2 As shown, the device may include:

[0076] The zero-crossing condition judgment module 202 is configured to receive a target torque request instruction, and determine whether the motor torque is in a zero-crossing condition based on the motor target torque and the motor actual torque corresponding to the target torque request instruction at the current moment, thereby obtaining a first judgment result.

[0077] The motor initial target torque change rate calculation module 204 is used to calculate the motor initial target torque change rate at the current moment if the first judgment result is yes, specifically including: obtaining the motor target torque at the previous moment before the current moment, where the time difference between the current moment and the previous moment is a predetermined time step; calculating the difference between the motor target torque at the current moment and the motor target torque at the previous moment to obtain a target torque difference, and dividing the target torque difference by the predetermined time step to obtain the motor initial target torque change rate at the current moment.

[0078] The average change rate calculation module 206 of the actual motor speed is used to calculate the difference in the actual motor speed between all two adjacent moments in a number of moments before the current moment, obtain a number of differences, calculate the average value of the number of differences, and obtain the average change rate of the actual motor speed, wherein the number of moments includes the current moment.

[0079] The first duration measurement module 208 is used to query a pre-established calibration table based on the throttle at the current moment and the gear position at the current moment to determine a first correction value for correcting the initial target torque change rate of the motor if the average change rate of the actual speed of the motor is greater than a pre-set first calibration value and less than a pre-set second calibration value; correct the initial target torque change rate of the motor based on the first correction value to obtain a corrected first target torque change rate, and adjust the actual torque of the motor based on the corrected first target torque change rate; dynamically calculate the average change rate of the actual speed of the motor as time goes by to obtain a first dynamic average change rate of the actual speed of the motor; and obtain a first duration in which the first dynamic average change rate of the actual speed of the motor remains greater than the pre-set first calibration value and less than the pre-set second calibration value.

[0080] The second duration measurement module 210 is used to query the pre-established calibration table based on the throttle at the latest moment and the gear at the latest moment to determine a second correction value for correcting the initial target torque change rate of the motor if the first dynamic average change rate of the actual speed of the motor becomes greater than the pre-set second calibration value, correct the initial target torque change rate of the motor based on the second correction value to obtain a corrected second target torque change rate; adjust the actual torque of the motor based on the corrected second target torque change rate; dynamically calculate the average change rate of the actual speed of the motor as time goes by to obtain the second dynamic average change rate of the actual speed of the motor, and obtain a second duration in which the second dynamic average change rate of the actual speed of the motor remains greater than the pre-set second calibration value.

[0081] The motor initial target torque correction removal module 212 is configured to remove the correction of the motor initial target torque change rate until the motor actual torque reaches the motor target torque at the current moment if any of the following conditions is met:

[0082] The first duration is greater than a preset correction time threshold;

[0083] The second duration is greater than the preset correction time threshold;

[0084] The first dynamic average change rate or the second dynamic average change rate is less than a preset change rate threshold, and the change rate threshold is a negative number.

[0085] Those skilled in the art will appreciate that the accompanying drawings are merely schematic diagrams of an embodiment, and the modules or processes in the accompanying drawings are not necessarily required to implement the present invention.

[0086] Those skilled in the art will appreciate that the modules in the devices of the embodiments may be distributed in the devices of the embodiments as described in the embodiments, or may be located in one or more devices different from the embodiments with corresponding changes. The modules of the above embodiments may be combined into one module or further divided into multiple submodules.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the zero-crossing torque of a motor of a P2 hybrid vehicle, characterized in that: include: receiving a target torque request instruction, and determining whether the motor torque is in a zero-crossing condition based on the motor target torque and the motor actual torque corresponding to the target torque request instruction at a current moment, to obtain a first determination result; If the first judgment result is yes, calculating the rate of change of the initial target torque of the motor at the current moment, specifically comprising: obtaining the target torque of the motor at a moment before the current moment, where the time difference between the current moment and the previous moment is a predetermined time step; calculating the difference between the target torque of the motor at the current moment and the target torque of the motor at the previous moment to obtain a target torque difference, and dividing the target torque difference by the predetermined time step to obtain the rate of change of the initial target torque of the motor at the current moment; Calculating the difference between the actual speed of the motor between all two adjacent moments in a number of moments before the current moment to obtain a number of differences, and calculating an average value of the number of differences to obtain an average rate of change of the actual speed of the motor, wherein the number of moments includes the current moment; If the average change rate of the actual speed of the motor is greater than a preset first calibration value and less than a preset second calibration value, a pre-established calibration table is queried based on the throttle at the current moment and the gear position at the current moment to determine a first correction value for correcting the initial target torque change rate of the motor; the initial target torque change rate of the motor is corrected based on the first correction value to obtain a corrected first target torque change rate, and the actual torque of the motor is adjusted based on the corrected first target torque change rate; as time goes by, the average change rate of the actual speed of the motor is dynamically calculated to obtain a first dynamic average change rate of the actual speed of the motor; and a first duration in which the first dynamic average change rate of the actual speed of the motor remains greater than the preset first calibration value and less than the preset second calibration value is obtained; If the first dynamic average change rate of the actual speed of the motor becomes greater than the pre-set second calibration value, the pre-established calibration table is queried based on the throttle at the latest moment and the gear position at the latest moment to determine a second correction value for correcting the initial target torque change rate of the motor, and the initial target torque change rate of the motor is corrected based on the second correction value to obtain a corrected second target torque change rate; the actual torque of the motor is adjusted based on the corrected second target torque change rate; as time progresses, the average change rate of the actual speed of the motor is dynamically calculated to obtain a second dynamic average change rate of the actual speed of the motor, and a second duration in which the second dynamic average change rate of the actual speed of the motor remains greater than the pre-set second calibration value is obtained; If any one of the following conditions is met, the correction of the rate of change of the initial target torque of the motor is released until the actual torque of the motor reaches the target torque of the motor at the current moment; the conditions include: The first duration is greater than a preset correction time threshold; The second duration is greater than the preset correction time threshold; The first dynamic average change rate or the second dynamic average change rate is less than a preset change rate threshold, and the change rate threshold is a negative number.

2. The method according to claim 1, characterized in that The zero-crossing condition includes: the motor target torque changes from negative torque or zero torque to positive torque, or the motor target torque changes from positive torque or zero torque to negative torque.

3. The method according to claim 1, characterized in that The time step size ranges from 0.005s to 0.015s.

4. The method according to claim 1, wherein For vehicles of the same model, a method for determining the first calibration value or the second calibration value includes: First, the motor torque change at the moment when the motor torque passes through zero is simulated according to the simulation method to obtain the initial calibration value; Based on the initial calibration value, a specific calibration is performed for a specific vehicle model during actual vehicle testing to calibrate a calibration value suitable for the specific vehicle model.

5. The method according to claim 1, wherein The motor target torque at the current moment is calculated based on the formula TH0 / (i1×i0), where symbol TH0 represents the wheel end target torque, symbol i1 represents the gear ratio, and symbol i0 represents the final reduction ratio.

6. The method according to claim 1, characterized in that The method for determining the preset correction time threshold includes: First, the motor torque change at the moment when the motor torque passes through zero is simulated according to the simulation method to obtain the initial correction time threshold; Based on the initial correction time threshold, a specific calibration is performed for a specific vehicle model during actual vehicle testing to calibrate a pre-set correction time threshold suitable for the specific vehicle model.

7. A motor torque zero-crossing control device for a P2 hybrid vehicle, characterized in that: include: a zero-crossing condition determination module, configured to receive a target torque request instruction, determine whether the motor torque is in a zero-crossing condition based on the motor target torque and the motor actual torque at a current moment corresponding to the target torque request instruction, and obtain a first determination result; a motor initial target torque change rate calculation module, configured to calculate the motor initial target torque change rate at the current moment if the first judgment result is yes, specifically comprising: obtaining the motor target torque at a moment before the current moment, where the time difference between the current moment and the previous moment is a predetermined time step; calculating the difference between the motor target torque at the current moment and the motor target torque at the previous moment to obtain a target torque difference; and dividing the target torque difference by the predetermined time step to obtain the motor initial target torque change rate at the current moment; an average rate of change calculation module for the actual motor speed, configured to calculate the difference in the actual motor speed between all two adjacent moments in a number of moments before the current moment, obtain a number of differences, calculate an average value of the number of differences, and obtain an average rate of change of the actual motor speed, wherein the number of moments includes the current moment; A first duration measurement module is configured to query a pre-established calibration table based on the throttle at the current moment and the gear position at the current moment to determine a first correction value for correcting the initial target torque change rate of the motor if the average change rate of the actual speed of the motor is greater than a pre-set first calibration value and less than a pre-set second calibration value; correct the initial target torque change rate of the motor based on the first correction value to obtain a corrected first target torque change rate, and adjust the actual torque of the motor based on the corrected first target torque change rate; dynamically calculate the average change rate of the actual speed of the motor as time progresses to obtain a first dynamic average change rate of the actual speed of the motor; and obtain a first duration in which the first dynamic average change rate of the actual speed of the motor remains greater than the pre-set first calibration value and less than the pre-set second calibration value; A second duration measurement module is configured to query the pre-established calibration table based on the throttle at the latest moment and the gear position at the latest moment to determine a second correction value for correcting the initial target torque change rate of the motor if the first dynamic average change rate of the actual speed of the motor becomes greater than the pre-set second calibration value; correct the initial target torque change rate of the motor based on the second correction value to obtain a corrected second target torque change rate; adjust the actual torque of the motor based on the corrected second target torque change rate; dynamically calculate the average change rate of the actual speed of the motor over time to obtain a second dynamic average change rate of the actual speed of the motor, and obtain a second duration in which the second dynamic average change rate of the actual speed of the motor remains greater than the pre-set second calibration value; The motor initial target torque correction removal module is configured to remove the correction of the motor initial target torque change rate until the motor actual torque reaches the motor target torque at the current moment if any one of the following conditions is met: The first duration is greater than a preset correction time threshold; The second duration is greater than the preset correction time threshold; The first dynamic average change rate or the second dynamic average change rate is less than a preset change rate threshold, and the change rate threshold is a negative number.

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