Zero-crossing control method and system for motor torque

Abstract

The present invention relates to permanent magnet synchronous motor technology, and provides a method and system for controlling the zero crossing of motor torque. The method determines in real time whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer; when the current state of the vehicle is judged to be a sudden acceleration state or a sudden deceleration state, it is determined whether the motor output torque value of the vehicle is less than or equal to a preset zero crossing threshold; when the motor output torque value is judged to be less than or equal to the zero crossing threshold, the rated value of the output slope of the motor output torque value is reduced. The present invention can actively identify the zero crossing state of the motor torque, thereby entering the torque zero crossing control, so that the main drive gear slowly fits the driven wheel to achieve a smooth transition.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet synchronous motors, and in particular to a zero-crossing control method and system for motor torque. Background Art

[0002] Under the national call for energy conservation and emission reduction, new energy vehicles are vigorously promoted, and automobile electrification is becoming more and more popular. The power of pure electric vehicles is changed from traditional engines to motor drive systems. In automotive motor drive systems, motor torque zero-crossing control is a basic issue that must be considered. When the driver steps on the accelerator pedal suddenly, under unrestricted conditions, the vehicle controller outputs a corresponding torque demand command to the motor drive system according to the accelerator pedal opening, and the motor drive system responds quickly to output the corresponding torque to drive the vehicle to accelerate. When the driver decelerates suddenly, the vehicle controller outputs a corresponding reverse torque command to the motor control system according to the brake pedal, and the motor control system responds quickly to output negative torque to decelerate the vehicle. During the switching process of rapid acceleration and rapid deceleration, due to the limitations of the manufacturing process level of the transmission mechanism, it cannot be closely matched, there is a certain space gap between the gears in the transmission process, and the positive and negative torques continue to switch through the zero point quickly. At this time, the vehicle is prone to shaking, accompanied by the collision sound of the transmission gears, which brings a bad driving experience. In severe cases, it will also cause the gears of the reduction box to collide and break. By improving the manufacturing process, the transmission mechanism can be made to cooperate closely. Due to the limitations of the current manufacturing process, this solution is very difficult, requires huge investment and has little effect. Another solution is for the vehicle controller to slow down the response to the accelerator pedal opening, that is, to increase the filtering time of the response to the accelerator pedal, thereby slowing down the positive and negative torque switching slope. This solution can reduce jitter and noise, but at the same time it also sacrifices the flexibility of the vehicle's accelerator pedal control and reduces the vehicle's acceleration and deceleration dynamic response. Summary of the invention

[0003] In view of the above, the present invention provides a zero-crossing control method and method for motor torque, which aims to solve the above technical problems.

[0004] To achieve the above object, the present invention provides a method for controlling the zero-crossing of a motor torque, the method comprising:

[0005] Based on the preset state observer, it is determined in real time whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state;

[0006] When it is determined that the current state of the vehicle is a rapid acceleration state or a rapid deceleration state, it is determined whether the motor output torque value of the vehicle is less than or equal to a preset zero-crossing threshold;

[0007] When it is determined that the motor output torque value is less than or equal to the zero-crossing threshold, the rated value of the output slope of the motor output torque value is reduced.

[0008] Preferably, after reducing the rated value of the output slope of the motor output torque value, the method further comprises:

[0009] It is determined in real time whether the motor output torque value is greater than a preset zero-crossing threshold value, and when it is determined that the motor output torque value is greater than the zero-crossing threshold value, the output slope is controlled to be restored to the rated value.

[0010] Preferably, the real-time determination of whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer includes:

[0011] When the gear position of the vehicle is the forward gear position, a first change rate of the accelerator pedal signal of the vehicle within a preset time period is calculated, and when the first change rate is greater than or equal to a first preset threshold value, and when the change rate of the brake pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid acceleration state;

[0012] When the vehicle is in reverse gear, the second change rate of the vehicle's accelerator pedal signal within a preset time period is calculated. When the second change rate is greater than or equal to a second preset threshold, and when the change rate of the signal of the vehicle's brake pedal is zero, it is determined that the vehicle's current state is a rapid acceleration state.

[0013] Preferably, the real-time determination of whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer includes:

[0014] When the gear position of the vehicle is the forward gear position, a third change rate of the brake pedal signal of the vehicle within a preset time period is calculated, and when the third change rate is greater than or equal to a third preset threshold value, and when the change rate of the accelerator pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid deceleration state;

[0015] When the vehicle is in the reverse gear, the fourth change rate of the brake pedal signal of the vehicle within a preset time period is calculated. When the fourth change rate is greater than or equal to the fourth preset threshold, and when the change rate of the signal of the accelerator pedal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid deceleration state.

[0016] Preferably, the zero-crossing threshold = rated torque value of the motor of the vehicle*10%.

[0017] To achieve the above object, the present invention further provides a zero-crossing control system for motor torque, the system further comprising:

[0018] The first judgment unit is used to judge in real time whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer;

[0019] The second judgment unit is used to judge whether the motor output torque value of the vehicle is less than or equal to a preset zero-crossing threshold value when the current state of the vehicle is judged to be a rapid acceleration state or a rapid deceleration state;

[0020] The first control unit is used to reduce the rated value of the output slope of the motor output torque value when it is determined that the motor output torque value is less than or equal to the zero-crossing threshold.

[0021] Preferably, the system further comprises:

[0022] The second control unit is configured to determine in real time whether the motor output torque value is greater than a preset zero-crossing threshold value, and when it is determined that the motor output torque value is greater than the zero-crossing threshold value, control the output slope to return to the rated value.

[0023] Preferably, the real-time determination of whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer includes:

[0024] When the gear position of the vehicle is the forward gear position, a first change rate of the accelerator pedal signal of the vehicle within a preset time period is calculated, and when the first change rate is greater than or equal to a first preset threshold value, and when the change rate of the brake pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid acceleration state;

[0025] When the vehicle is in reverse gear, the second change rate of the vehicle's accelerator pedal signal within a preset time period is calculated. When the second change rate is greater than or equal to a second preset threshold, and when the change rate of the signal of the vehicle's brake pedal is zero, it is determined that the vehicle's current state is a rapid acceleration state.

[0026] Preferably, the real-time determination of whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer includes:

[0027] When the gear position of the vehicle is the forward gear position, a third change rate of the brake pedal signal of the vehicle within a preset time period is calculated, and when the third change rate is greater than or equal to a third preset threshold value, and when the change rate of the accelerator pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid deceleration state;

[0028] When the vehicle is in the reverse gear, the fourth change rate of the brake pedal signal of the vehicle within a preset time period is calculated. When the fourth change rate is greater than or equal to the fourth preset threshold, and when the change rate of the signal of the accelerator pedal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid deceleration state.

[0029] Preferably, the zero-crossing threshold = rated torque value of the motor of the vehicle*10%.

[0030] The motor torque zero-crossing control method and system proposed in the present invention optimize and reduce the motor torque zero-crossing rate from the control level, so that the main drive gear actively and slowly fits the driven wheel tooth surface to reduce the impact. The motor controller observes the vehicle running status in real time, predicts the rapid acceleration and acceleration and deceleration commands in advance, actively identifies the motor torque zero-crossing state, actively enters the torque zero-crossing control, and controls the main drive gear to slowly fit the driven wheel to achieve a smooth transition. Then identify the exit torque zero-crossing state, exit the torque zero-crossing control, and quickly respond to the vehicle controller torque command to achieve smooth vehicle acceleration and deceleration switching. Processing from the control level can save huge cost investments such as manufacturing process improvements and equipment replacement; active torque zero-crossing control can solve the problem of untimely vehicle acceleration and deceleration dynamic response caused by traditional control methods. The scheme has strong adaptability. According to different vehicle models, more accurate identification and control can be achieved by changing parameters, improving vehicle comfort, and reducing the failure rate of the transmission mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flowchart of a zero-crossing control method for motor torque provided by the present invention;

[0032] Figure 2 A schematic diagram of a zero-crossing control system structure of a motor torque provided by the present invention;

[0033] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] Figure 1 FIG. 1 is a flow chart of a preferred embodiment of the zero-crossing control method of the motor torque of the present invention. Figure 1 The zero-crossing control method of the motor torque shown in the figure comprises:

[0036] S10: Determine in real time whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer;

[0037] In this embodiment, the motor controller is pre-configured with a state observer, which can detect the current vehicle gear signal, the opening degree of the accelerator pedal and its rate of change, the opening degree of the brake pedal and its rate of change, and can then determine in real time whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state. It should be noted that the state observer in this embodiment refers to a custom mathematical model with a calculated acquired signal.

[0038] In one embodiment, the real-time determination of whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer includes:

[0039] When the gear position of the vehicle is the forward gear position, a first change rate of the accelerator pedal signal of the vehicle within a preset time period is calculated, and when the first change rate is greater than or equal to a first preset threshold value, and when the change rate of the brake pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid acceleration state;

[0040] When the vehicle is in reverse gear, the second change rate of the vehicle's accelerator pedal signal within a preset time period is calculated. When the second change rate is greater than or equal to a second preset threshold, and when the change rate of the signal of the vehicle's brake pedal is zero, it is determined that the vehicle's current state is a rapid acceleration state.

[0041] The preset time period may refer to 0.5 seconds, the first preset threshold may refer to 50% of the throttle opening range, and the second preset threshold may refer to 40%-60% of the throttle opening range.

[0042] Further, when the first change rate is less than a first preset threshold value, and when the change rate of the signal when the brake pedal of the vehicle is zero, it is determined that the vehicle is in a flat state. When the second change rate is less than a second preset threshold value, and when the change rate of the signal when the brake pedal of the vehicle is zero, it is determined that the vehicle is in a flat state. Zero-crossing control does not need to be performed in a flat state.

[0043] In one embodiment, the real-time determination of whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer includes:

[0044] When the gear position of the vehicle is the forward gear position, a third change rate of the brake pedal signal of the vehicle within a preset time period is calculated, and when the third change rate is greater than or equal to a third preset threshold value, and when the change rate of the accelerator pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid deceleration state;

[0045] When the vehicle is in the reverse gear, the fourth change rate of the brake pedal signal of the vehicle within a preset time period is calculated. When the fourth change rate is greater than or equal to the fourth preset threshold, and when the change rate of the signal of the accelerator pedal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid deceleration state.

[0046] The preset time period may refer to 0.5 seconds, the third preset threshold may refer to 50% of the brake opening range, and the fourth preset threshold may refer to 40%-60% of the brake opening range.

[0047] Further, when the third rate of change is less than the third preset threshold value, and when the rate of change of the accelerator pedal signal of the vehicle is zero, it is determined that the vehicle is in a gentle state. When the fourth rate of change is less than the fourth preset threshold value, and when the rate of change of the accelerator pedal signal of the vehicle is zero, it is determined that the vehicle is in a gentle state. Zero-crossing control does not need to be performed in a gentle state.

[0048] S20: When it is determined that the current state of the vehicle is a rapid acceleration state or a rapid deceleration state, determining whether the motor output torque value of the vehicle is less than or equal to a preset zero-crossing threshold;

[0049] In this embodiment, when it is determined that the current state of the vehicle is a rapid acceleration state or a rapid deceleration state, it is determined whether the motor output torque value of the vehicle is less than or equal to a preset zero-crossing threshold value, so as to determine whether the motor is in a zero-crossing state. Further, the zero-crossing threshold value is the motor rated torque value of the vehicle*10%.

[0050] Specifically, when the motor rotates forward (for example, the gear is the forward gear), the motor output torque value is within the range of (0 to the zero-crossing threshold), and the vehicle is in a state of rapid acceleration or rapid deceleration, the motor is judged to be in a zero-crossing state. When the motor rotates reversely (for example, the gear is the reverse gear), the motor output torque value is (0 to the zero-crossing threshold), and the vehicle is in a state of rapid acceleration or rapid deceleration, the motor is judged to be in a zero-crossing state.

[0051] S30: when it is determined that the motor output torque value is less than or equal to the zero-crossing threshold, reducing the rated value of the output slope of the motor output torque value;

[0052] In this embodiment, when the current state of the vehicle is judged to be a rapid acceleration state or a rapid deceleration state, and when the motor output torque value is judged to be less than or equal to the zero-crossing threshold, the motor is judged to be in a zero-crossing state, and the motor torque zero-crossing control mode is entered. At this time, the rated value of the output slope of the motor output torque value can be reduced, so that the main drive gear actively and slowly fits the driven gear tooth surface to reduce the impact. For example, the motor torque output slope is adjusted from 1:1 to 0.5:1.

[0053] In one embodiment, after reducing the rated value of the output slope of the motor output torque value, the method further comprises:

[0054] It is determined in real time whether the motor output torque value is greater than a preset zero-crossing threshold value, and when it is determined that the motor output torque value is greater than the zero-crossing threshold value, the output slope is controlled to be restored to the rated value.

[0055] After adjusting the output slope of the motor output torque value, it is determined in real time whether the motor output torque value is greater than a preset zero-crossing threshold value. When it is determined that the motor output torque value is greater than the zero-crossing threshold value, the output slope is controlled to be restored to the rated value. Exit the motor torque zero-crossing control mode and respond to the motor torque output command normally, for example, adjusting the motor torque output slope from 0.5:1 to 1:1.

[0056] The speed at which the motor torque passes through zero can be optimized and reduced from the control level, allowing the main drive gear to actively and slowly fit the driven gear tooth surface to reduce impact.

[0057] Figure 2 A schematic diagram of a zero-crossing control system structure of a motor torque provided by the present invention. The zero-crossing control system of the motor torque includes:

[0058] The first judgment unit is used to judge in real time whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer;

[0059] The second judgment unit is used to judge whether the motor output torque value of the vehicle is less than or equal to a preset zero-crossing threshold value when the current state of the vehicle is judged to be a rapid acceleration state or a rapid deceleration state;

[0060] The first control unit is used to reduce the rated value of the output slope of the motor output torque value when it is determined that the motor output torque value is less than or equal to the zero-crossing threshold.

[0061] In one embodiment, the system further comprises:

[0062] The second control unit is configured to determine in real time whether the motor output torque value is greater than a preset zero-crossing threshold value, and when it is determined that the motor output torque value is greater than the zero-crossing threshold value, control the output slope to return to the rated value.

[0063] In one embodiment, the real-time determination of whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer includes:

[0064] When the gear position of the vehicle is the forward gear position, a first change rate of the accelerator pedal signal of the vehicle within a preset time period is calculated, and when the first change rate is greater than or equal to a first preset threshold value, and when the change rate of the brake pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid acceleration state;

[0065] When the vehicle is in reverse gear, the second change rate of the vehicle's accelerator pedal signal within a preset time period is calculated. When the second change rate is greater than or equal to a second preset threshold, and when the change rate of the signal of the vehicle's brake pedal is zero, it is determined that the vehicle's current state is a rapid acceleration state.

[0066] In one embodiment, the real-time determination of whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer includes:

[0067] When the gear position of the vehicle is the forward gear position, a third change rate of the brake pedal signal of the vehicle within a preset time period is calculated, and when the third change rate is greater than or equal to a third preset threshold value, and when the change rate of the accelerator pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid deceleration state;

[0068] When the vehicle is in the reverse gear, the fourth change rate of the brake pedal signal of the vehicle within a preset time period is calculated. When the fourth change rate is greater than or equal to the fourth preset threshold, and when the change rate of the signal of the accelerator pedal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid deceleration state.

[0069] In one embodiment, the zero-crossing threshold=rated torque value of the motor of the vehicle*10%.

[0070] The specific implementation of the zero-crossing control system of the motor torque of the present invention is substantially the same as the specific implementation of the zero-crossing control method of the motor torque described above, and will not be described in detail herein.

[0071] It should be noted that the serial numbers of the above-mentioned embodiments of the present invention are only for description and do not represent the advantages and disadvantages of the embodiments. And the terms "including", "comprising" or any other variants thereof in this article are intended to cover non-exclusive inclusion, so that a process, device, article or method including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, device, article or method. In the absence of further restrictions, an element defined by the sentence "including a ..." does not exclude the presence of other identical elements in the process, device, article or method including the element.

[0072] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for controlling zero-crossing of motor torque, characterized in that: The method comprises: Based on the preset state observer, it is determined in real time whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state; When it is determined that the current state of the vehicle is a rapid acceleration state or a rapid deceleration state, it is determined whether the motor output torque value of the vehicle is less than or equal to a preset zero-crossing threshold; When it is determined that the motor output torque value is less than or equal to the zero-crossing threshold, reducing the rated value of the output slope of the motor output torque value; After reducing the rated value of the output slope of the motor output torque value, the method further comprises: Determine in real time whether the motor output torque value is greater than a preset zero-crossing threshold value, and when it is determined that the motor output torque value is greater than the zero-crossing threshold value, control the output slope to return to the rated value; The method of determining in real time whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer includes: When the gear position of the vehicle is the forward gear position, a first change rate of the accelerator pedal signal of the vehicle within a preset time period is calculated, and when the first change rate is greater than or equal to a first preset threshold value, and when the change rate of the brake pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid acceleration state; When the gear position of the vehicle is the reverse gear position, a second change rate of the accelerator pedal signal of the vehicle within a preset time period is calculated, and when the second change rate is greater than or equal to a second preset threshold value, and when the change rate of the brake pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid acceleration state; The method of determining in real time whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer includes: When the gear position of the vehicle is the forward gear position, a third change rate of the brake pedal signal of the vehicle within a preset time period is calculated, and when the third change rate is greater than or equal to a third preset threshold value, and when the change rate of the accelerator pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid deceleration state; When the vehicle is in reverse gear, the fourth change rate of the brake pedal signal of the vehicle within a preset time period is calculated. When the fourth change rate is greater than or equal to a fourth preset threshold value, and when the change rate of the accelerator pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid deceleration state.

2. The method for controlling the zero-crossing torque of a motor according to claim 1, characterized in that: The zero-crossing threshold = the rated torque value of the motor of the vehicle .

3. A motor torque zero-crossing control system using the motor torque zero-crossing control method according to claim 1, characterized in that: The system comprises: The first judgment unit is used to judge in real time whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer; The second judgment unit is used to judge whether the motor output torque value of the vehicle is less than or equal to a preset zero-crossing threshold value when the current state of the vehicle is judged to be a rapid acceleration state or a rapid deceleration state; The first control unit is used to reduce the rated value of the output slope of the motor output torque value when it is determined that the motor output torque value is less than or equal to the zero-crossing threshold.

4. The zero-crossing control system of the motor torque as claimed in claim 3, characterized in that: The system further comprises: The second control unit is configured to determine in real time whether the motor output torque value is greater than a preset zero-crossing threshold value, and when it is determined that the motor output torque value is greater than the zero-crossing threshold value, control the output slope to return to the rated value.

5. The zero-crossing control system of the motor torque as claimed in claim 3 or 4, characterized in that: The method of determining in real time whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer includes: When the gear position of the vehicle is the forward gear position, a first change rate of the accelerator pedal signal of the vehicle within a preset time period is calculated, and when the first change rate is greater than or equal to a first preset threshold value, and when the change rate of the brake pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid acceleration state; When the vehicle is in reverse gear, the second change rate of the vehicle's accelerator pedal signal within a preset time period is calculated. When the second change rate is greater than or equal to a second preset threshold, and when the change rate of the signal of the vehicle's brake pedal is zero, it is determined that the vehicle's current state is a rapid acceleration state.

6. The zero-crossing control system of the motor torque as claimed in claim 5, characterized in that: The method of determining in real time whether the current state of the vehicle is a sudden acceleration state or a sudden deceleration state based on a preset state observer includes: When the gear position of the vehicle is the forward gear position, a third change rate of the brake pedal signal of the vehicle within a preset time period is calculated, and when the third change rate is greater than or equal to a third preset threshold value, and when the change rate of the accelerator pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid deceleration state; When the vehicle is in reverse gear, the fourth change rate of the brake pedal signal of the vehicle within a preset time period is calculated. When the fourth change rate is greater than or equal to a fourth preset threshold value, and when the change rate of the accelerator pedal signal of the vehicle is zero, it is determined that the current state of the vehicle is a rapid deceleration state.

7. The zero-crossing control system of the motor torque as claimed in claim 3, characterized in that: The zero-crossing threshold = the rated torque value of the motor of the vehicle .

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