A vehicle control method and apparatus

Abstract

The application discloses a kind of vehicle control method and device, belong to vehicle control field.The method includes: whole vehicle controller according to current motor temperature, current motor controller temperature, current battery can be distributed to motor controller power and motor controller input direct current voltage, motor operating speed and motor external characteristic parameter, motor controller three-phase output alternating current, motor controller overload progress, motor controller fault level respectively correspond to calculate the first to seventh maximum output torque of motor controller;Take the minimum value in the first to seventh maximum output torque as request torque limit and send to corresponding motor controller.The application avoids power mutation by multi-dimensional torque limiting method, improves driving smoothness, and effectively prevents motor controller damage.

Description

Technical Field

[0001] This invention belongs to the field of vehicle control, specifically, it relates to a vehicle control method and apparatus. Background Technology

[0002] For complex road conditions such as long uphill and downhill sections, vehicles may operate in high-power output or energy recovery mode for extended periods, which can easily overload or overheat the motor controller and affect vehicle operation.

[0003] In existing control methods, the motor controller and the vehicle controller monitor and calculate the overload progress and temperature of the motor controller separately, and control the output power of the motor during vehicle operation. However, because the vehicle controller and the motor controller operate their protection logic independently, conflicts can easily occur between the two sets of protection logic, leading to drastic fluctuations in the motor's output torque and speed. Specifically, this manifests as frequent fluctuations in vehicle speed and abnormal vehicle vibration during driving.

[0004] Furthermore, existing over-temperature and overload protection strategies typically employ a step-type torque limiting method, but such step-type torque changes can lead to a sudden decrease in vehicle power, resulting in a poor driving experience. Additionally, existing solutions often only provide protection from a single dimension, failing to comprehensively reflect the actual operating state of the motor controller, thus limiting their protection effectiveness. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of existing technologies and proposes a vehicle control method and a self-protection optimization control device for commercial vehicle electronic control. The technical solution adopted by this invention is as follows:

[0006] This invention provides a vehicle control method applied to a vehicle controller, comprising:

[0007] The first maximum output torque is calculated based on the motor temperature and motor operating speed.

[0008] The second maximum output torque is calculated based on the motor controller temperature.

[0009] The third maximum output torque is calculated based on the power that the current battery can allocate to the motor controller and the DC input voltage of the motor controller;

[0010] The fourth maximum output torque is calculated based on the motor's operating speed and external characteristic parameters.

[0011] The fifth maximum output torque is calculated based on the actual three-phase AC current output by the motor controller.

[0012] The sixth maximum output torque is calculated based on the overload progress of the motor controller;

[0013] Calculate the seventh maximum output torque based on the motor controller fault level;

[0014] Select the minimum value from the first to seventh maximum output torques mentioned above as the requested torque limit value;

[0015] Based on the requested torque limit value, a torque control command is sent to the motor controller.

[0016] Furthermore, based on the motor temperature and motor operating speed, the first maximum output torque is calculated, including:

[0017] Obtain the secondary and tertiary over-temperature thresholds of the motor;

[0018] When the motor temperature is less than the difference between the secondary over-temperature threshold and the preset first offset, the maximum torque of the motor is taken as the first maximum output torque.

[0019] When the motor temperature is greater than or equal to the difference between the secondary over-temperature threshold and the preset first offset, but less than the secondary over-temperature threshold, the first maximum output torque is determined according to the first linear increasing relationship. The first maximum output torque increases linearly from half of the peak torque to the maximum torque of the motor.

[0020] When the motor temperature is greater than or equal to the second-level over-temperature threshold and less than the third-level over-temperature threshold, the first maximum output torque is determined according to the second linear decreasing relationship. The first maximum output torque decreases linearly from half of the peak torque to zero.

[0021] Furthermore, based on the motor controller temperature, the second maximum output torque is calculated, including:

[0022] Obtain the secondary and tertiary over-temperature thresholds of the motor controller;

[0023] When the temperature of the motor controller is less than the difference between the secondary over-temperature threshold of the motor controller and the preset second offset, the maximum torque of the motor is taken as the second maximum output torque.

[0024] When the temperature of the motor controller is greater than or equal to the difference between the second-level over-temperature threshold of the motor controller and the preset second offset, but less than the second-level over-temperature threshold of the motor controller, the second maximum output torque is determined according to the third linear increasing relationship. The second maximum output torque increases linearly from half of the peak torque to the maximum torque of the motor.

[0025] When the temperature of the motor controller is greater than or equal to the second-level over-temperature threshold of the motor controller and less than the third-level over-temperature threshold of the motor controller, the second maximum output torque is determined according to the fourth linear decreasing relationship. The second maximum output torque decreases linearly from half of the peak torque to zero.

[0026] Furthermore, based on the power that the current battery can allocate to the motor controller and the DC input voltage of the motor controller, the third maximum output torque is calculated, including:

[0027] The power that the battery can currently allocate to the motor controller is obtained by subtracting the power of auxiliary drive appliances, thermal management appliances, and other appliances from the product of the battery bus voltage and the current maximum output current of the battery.

[0028] The maximum input DC current of the motor controller is determined based on the ratio of the power that can be allocated to the motor controller to the input DC voltage of the motor controller.

[0029] When the actual input DC current of the motor controller is greater than the sum of the maximum input DC current and the first current threshold, the requested torque is reduced according to the fifth linear decreasing relationship until the actual input DC current of the motor controller is equal to the maximum input DC current.

[0030] When the actual input DC current of the motor controller is greater than or equal to the difference between the maximum input DC current and the first current threshold, and less than or equal to the sum of the maximum input DC current and the first current threshold, the current output torque of the motor is taken as the third maximum output torque.

[0031] When the actual input DC current of the motor controller is less than the difference between the maximum input DC current and the first current threshold, the maximum torque of the motor is taken as the third maximum output torque.

[0032] Furthermore, based on the motor's operating speed and external characteristic parameters, the fourth maximum output torque is calculated, including:

[0033] When the motor's operating speed is less than the speed at the weakening magnetic point, the motor is in the constant torque region, and the motor's peak torque is taken as the fourth maximum output torque.

[0034] When the motor's operating speed is greater than or equal to the speed at the weakening magnetic point, the fourth maximum output torque is determined according to the motor's external characteristic curve.

[0035] Furthermore, based on the actual three-phase AC current output by the motor controller, the fifth maximum output torque is calculated, including:

[0036] When a secondary over-temperature fault is triggered in the motor controller and the motor operating speed is greater than or equal to the speed at the field weakening point, the rated output three-phase AC current of the motor controller is obtained.

[0037] When the actual output three-phase AC current of the motor controller is greater than the sum of the rated output three-phase AC current and the second current threshold, the requested torque is reduced according to the sixth linear decreasing relationship until the actual output three-phase AC current of the motor controller is equal to the rated output three-phase AC current.

[0038] When the actual output three-phase AC current of the motor controller is greater than or equal to the difference between the rated output three-phase AC current and the second current threshold, and less than or equal to the sum of the rated output three-phase AC current and the second current threshold, the current output torque of the motor is taken as the fifth maximum output torque.

[0039] When the actual output three-phase AC current of the motor controller is less than the difference between the rated output three-phase AC current and the second current threshold, the maximum torque of the motor is taken as the fifth maximum output torque.

[0040] Furthermore, based on the overload progress of the motor controller, the sixth maximum output torque is calculated, including:

[0041] When the motor controller overload level is greater than or equal to 50%, the sixth maximum output torque is determined according to the seventh linear decreasing relationship. The sixth maximum output torque is:

[0042] ;

[0043] in, This indicates the sixth maximum output torque of the motor controller. This indicates the maximum torque of the motor. Indicates the overload progress of the motor controller;

[0044] When the motor controller overload is less than 50%, the motor's maximum torque is taken as the sixth maximum output torque.

[0045] Furthermore, based on the motor controller fault level, the seventh maximum output torque is calculated, including:

[0046] When the motor controller fault level is Level 1, the maximum torque of the motor is not limited;

[0047] When the motor controller fault level is level two, the maximum torque of the motor is partially limited.

[0048] When the motor controller fault level is three, the maximum torque of the motor will be limited to zero.

[0049] Furthermore, the method of the present invention also includes:

[0050] Obtain vehicle tilt angle and vehicle acceleration information;

[0051] The current road conditions are determined based on the vehicle's tilt angle. The current road conditions include uphill road conditions, downhill road conditions, and ordinary road conditions.

[0052] Determine the vehicle's load status based on vehicle acceleration information;

[0053] Based on the current road conditions and vehicle load status, determine the current operating conditions and adjust the control strategy of the motor controller accordingly.

[0054] The control strategy for adjusting the motor controller based on the current operating conditions includes:

[0055] When operating on an uphill slope, reduce the maximum torque that the vehicle controller can send to the motor controller.

[0056] When operating under normal road conditions, the maximum torque that the vehicle controller can send to the motor controller is equal to the torque request limit value.

[0057] When in downhill condition, if the duration of motor energy recovery exceeds the set value, the motor energy recovery and physical braking will be alternately activated in a cycle.

[0058] Different load conditions correspond to different throttle MAP curves, and the same throttle pedal depth corresponds to different requested torques.

[0059] The present invention also provides a vehicle control device, comprising:

[0060] The acquisition module is used to acquire motor temperature, motor controller temperature, motor operating speed, motor controller input DC voltage, motor controller actual input DC current, motor controller actual output three-phase AC current, motor controller overload progress, and motor controller fault level.

[0061] The calculation module is used to calculate the first maximum output torque based on the motor temperature and motor operating speed, the second maximum output torque based on the motor controller temperature, the third maximum output torque based on the power that the current battery can allocate to the motor controller and the DC input voltage of the motor controller, the fourth maximum output torque based on the motor operating speed and motor external characteristic parameters, the fifth maximum output torque based on the actual three-phase AC current output by the motor controller, the sixth maximum output torque based on the overload progress of the motor controller, and the seventh maximum output torque based on the fault level of the motor controller.

[0062] The selection module is used to select the minimum value from the first maximum output torque to the seventh maximum output torque as the requested torque limit value;

[0063] The control module is used to send torque control commands to the motor controller based on the requested torque limit value.

[0064] The technical effects of this invention are as follows: The vehicle control method of this invention optimizes the step-like protection under abnormal conditions such as over-temperature and overload into a smooth transition through multi-dimensional linear torque limiting, avoiding sudden power changes and improving driving smoothness. It also takes the minimum value from seven constraint dimensions for comprehensive protection, effectively preventing damage to the motor controller. Through the adaptive working condition identification method of slope and acceleration sensors, it realizes accurate identification and strategy switching of nine road condition and load conditions. When going uphill, it reasonably limits torque, and when going downhill, it alternately intervenes in energy recovery and physical braking to prevent system over-temperature and overload. It also matches the throttle MAP curve of different load conditions, which significantly improves driving comfort, handling and system safety. Attached Figure Description

[0065] Figure 1 This is a flowchart of a vehicle control method provided in an embodiment of the present invention. Detailed Implementation

[0066] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. This is to help those skilled in the art to have a more complete, accurate, and in-depth understanding of the inventive concept and technical solutions of the present invention, and to facilitate its implementation. It should be noted that the terms "first," "second," etc., used in this application are only for the convenience of describing the technical solutions and to distinguish components; the corresponding component configurations may be the same or different, and are not intended to limit the scope of this application. To make the technical solutions of the present invention clearer, the present invention will be explained and illustrated through the following embodiments.

[0067] like Figure 1 As shown, this embodiment of the invention provides a vehicle control method, namely, a method for linearly limiting the maximum output torque of a motor controller based on multi-dimensional constraints. The method includes:

[0068] The vehicle controller acquires and writes the maximum available drive or recovery torque of the drive axle. Then, it acquires the motor temperature, motor controller temperature, motor operating speed, motor controller input DC voltage, motor controller actual input DC current, motor controller actual output three-phase AC current, motor controller overload progress, and motor controller fault level.

[0069] Calculate the first maximum output torque based on the motor temperature and motor operating speed;

[0070] Calculate the second maximum output torque based on the motor controller temperature;

[0071] Calculate the third maximum output torque based on the power that the current battery can allocate to the motor controller and the DC input voltage of the motor controller;

[0072] Calculate the fourth maximum output torque based on the motor's operating speed and external characteristic parameters;

[0073] Calculate the fifth maximum output torque based on the actual three-phase AC current output by the motor controller.

[0074] Calculate the sixth maximum output torque based on the overload progress of the motor controller;

[0075] Calculate the seventh maximum output torque based on the motor controller fault level;

[0076] The minimum value among the first, second, third, fourth, fifth, sixth, and seventh maximum output torques is selected as the requested torque limit value; wherein the aforementioned first to seventh maximum output torques must be less than or equal to

[0077] Based on the requested torque limit value, a torque control command is sent to the motor controller.

[0078] Among them, the maximum output torque of the first to seventh parameters must be less than or equal to the maximum available drive or recovery torque of the drive axle.

[0079] Specifically, the method includes steps 201 to 208.

[0080] Step 201: Calculate the first maximum output torque based on the motor temperature and motor operating speed, including:

[0081] Obtain the secondary and tertiary over-temperature thresholds of the motor;

[0082] When the motor temperature is less than the difference between the secondary over-temperature threshold and the preset first offset, the maximum torque of the motor is taken as the first maximum output torque.

[0083] When the motor temperature is greater than or equal to the difference between the secondary over-temperature threshold and the preset first offset, but less than the secondary over-temperature threshold, the first maximum output torque is determined according to the first linear increasing relationship. The first maximum output torque increases linearly from half of the peak torque to the maximum torque of the motor.

[0084] When the motor temperature is greater than or equal to the second-level over-temperature threshold and less than the third-level over-temperature threshold, the first maximum output torque is determined according to the second linear decreasing relationship. The first maximum output torque decreases linearly from half of the peak torque to zero.

[0085] Due to hardware heat dissipation limitations, drive motors have their level 3 and level 2 over-temperature fault thresholds determined through testing. Currently, the commonly used level 3 over-temperature fault protection strategy is shutdown, and the level 2 over-temperature fault protection strategy is limiting the motor's peak torque to 50%. Since the output torque limitation is a step-like change, the actual driving experience is poor, resulting in a sudden drop in vehicle power. To optimize this issue, the level 2 over-temperature fault protection strategy should be changed from step-like torque limitation to linear torque limitation, and linear torque limitation should be applied before and after level 2 over-temperature to make the torque limitation smoother. In this embodiment, the first maximum output torque of the motor controller is calculated based on the current motor temperature, expressed by the following formula:

[0086] ;

[0087] in, This indicates the maximum output torque of the motor controller calculated based on the current motor temperature. This indicates the maximum torque of the motor. This indicates the current motor temperature. This indicates the secondary over-temperature threshold of the motor. This indicates the motor's three-stage over-temperature threshold. For example, if the motor's second-stage over-temperature threshold is 150 degrees Celsius, and the current motor temperature is 146 degrees Celsius, the maximum output torque of the motor controller is 0.9 times the motor's maximum torque.

[0088] Step 202: Calculate the second maximum output torque based on the motor controller temperature, including:

[0089] Obtain the secondary and tertiary over-temperature thresholds of the motor controller;

[0090] When the temperature of the motor controller is less than the difference between the secondary over-temperature threshold of the motor controller and the preset second offset, the maximum torque of the motor is taken as the second maximum output torque.

[0091] When the temperature of the motor controller is greater than or equal to the difference between the second-level over-temperature threshold of the motor controller and the preset second offset, but less than the second-level over-temperature threshold of the motor controller, the second maximum output torque is determined according to the third linear increasing relationship. The second maximum output torque increases linearly from half of the peak torque to the maximum torque of the motor.

[0092] When the temperature of the motor controller is greater than or equal to the second-level over-temperature threshold of the motor controller and less than the third-level over-temperature threshold of the motor controller, the second maximum output torque is determined according to the fourth linear decreasing relationship. The second maximum output torque decreases linearly from half of the peak torque to zero.

[0093] Due to hardware heat dissipation limitations, motor controllers typically have their level 3 and level 2 over-temperature fault thresholds determined through testing. Currently, the commonly used level 3 over-temperature fault protection strategy is shutdown, while the level 2 over-temperature fault protection strategy is limiting the motor's peak torque to 50%. Since the output torque limitation is abrupt, the actual driving experience is poor, resulting in a sudden drop in vehicle power. To optimize this, the level 2 over-temperature fault protection strategy for the motor controller should be changed from abrupt torque limitation to linear torque limitation, and linear torque limitation should be applied both before and after the level 2 over-temperature event to make the torque limitation smoother. In this embodiment, the second maximum output torque of the motor controller is calculated based on the current motor controller temperature, expressed by the following formula:

[0094] ;

[0095] in, This indicates the maximum output torque of the motor controller calculated based on the current motor controller temperature. This indicates the maximum torque of the motor. This indicates the current temperature of the motor controller. This indicates the secondary over-temperature threshold of the motor controller. This indicates the three-level over-temperature threshold of the motor controller.

[0096] For example, if the secondary over-temperature threshold of the motor controller is 100 degrees Celsius, and the current temperature of the motor controller is 91 degrees Celsius, the maximum output torque of the motor controller is 0.95 times the maximum torque of the motor.

[0097] Step 203: Based on the power that the current battery can allocate to the motor controller and the DC input voltage of the motor controller, calculate the third maximum output torque, including:

[0098] The power that the battery can currently allocate to the motor controller is obtained by subtracting the power of auxiliary drive appliances, thermal management appliances, and other appliances from the product of the battery bus voltage and the current maximum output current of the battery.

[0099] The maximum input DC current of the motor controller is determined based on the ratio of the power that can be allocated to the motor controller to the input DC voltage of the motor controller.

[0100] When the actual input DC current of the motor controller is greater than the sum of the maximum input DC current and the first current threshold, the requested torque is reduced according to the fifth linear decreasing relationship until the actual input DC current of the motor controller is equal to the maximum input DC current.

[0101] When the actual input DC current of the motor controller is greater than or equal to the difference between the maximum input DC current and the first current threshold, and less than or equal to the sum of the maximum input DC current and the first current threshold, the current output torque of the motor is taken as the third maximum output torque.

[0102] When the actual input DC current of the motor controller is less than the difference between the maximum input DC current and the first current threshold, the maximum torque of the motor is taken as the third maximum output torque.

[0103] Specifically, after the vehicle's high voltage is applied, the Battery Management System (BMS) will feed back the current maximum output current of the battery to the vehicle controller based on the current state of the battery. The vehicle controller can then calculate the power that the battery can currently allocate to the motor controller, expressed by the following formula:

[0104] ;

[0105] This indicates the power that can be allocated to the motor controller. This indicates the battery's bus voltage. This indicates the current maximum output current of the battery. Indicates the power of the auxiliary drive electrical components. Indicates the power of the thermal management appliance. This indicates the power of other electrical appliances (mounted motors, external DC-DC converters, etc.). For example, if the battery bus voltage is 600V, the current maximum battery output current is 100A, the power of the auxiliary drive appliances is 5kW, the power of the thermal management appliances is 5kW, and the power of other electrical appliances is 0, then the power allocated to the motor controller is 50kW.

[0106] Based on the power allocated to the motor controller and the input DC voltage of the motor controller, the maximum DC current of the motor controller can be calculated, i.e.: ;

[0107] in, This indicates the power that can be allocated to the motor controller. This indicates the input DC voltage of the motor controller. This indicates the maximum input DC current of the motor controller. For example, if the power that can be allocated to the motor controller is 50kW and the input DC voltage of the motor controller is 600V, the maximum input DC current of the motor controller is 83.3A.

[0108] Finally, based on the power that the battery can currently allocate to the motor controller and the DC input voltage of the motor controller, the third maximum output torque of the motor controller is calculated, and expressed by the following formula:

[0109] ;

[0110] in, This indicates the fourth maximum output torque of the motor controller. This indicates the current output torque of the motor. This indicates the maximum input DC current of the motor controller. This represents the actual input DC current of the motor controller. This indicates the maximum torque of the motor. The preset current threshold can be adjusted according to the actual vehicle conditions to increase torque stability.

[0111] The principle is as follows: When the actual input DC current of the motor controller is greater than the maximum input DC current of the motor controller and exceeds a preset threshold, the vehicle controller linearly reduces the requested torque until the actual input DC current of the motor controller is approximately equal to the maximum input DC current of the motor controller; when the actual input DC current of the motor controller fluctuates around the maximum input DC current of the motor controller, the maximum output torque of the motor controller is equal to the current output torque of the motor; when the actual input DC current of the motor controller is less than the maximum input DC current of the motor controller and exceeds a preset threshold, the maximum output torque of the motor controller is the maximum torque of the motor.

[0112] Step 204: Calculate the fourth maximum output torque based on the motor's operating speed and external characteristic parameters, including:

[0113] When the motor's operating speed is less than the speed at the weakening magnetic point, the motor is in the constant torque region, and the motor's peak torque is taken as the fourth maximum output torque.

[0114] When the motor's operating speed is greater than or equal to the speed at the weakening magnetic point, the fourth maximum output torque is determined according to the motor's external characteristic curve.

[0115] The drive motor undergoes calibration on a test bench with the motor controller. The motor's external characteristic curve is calibrated to determine its maximum torque using a fixed stepper speed. When the motor's operating speed is lower than the preset field weakening point speed, the motor is in the constant torque region, and its maximum torque is always the peak torque, which corresponds to the fourth maximum output torque of the motor controller. The maximum torque is equal to the peak torque of the motor. When the motor's operating speed is greater than or equal to the preset field weakening point speed, the motor's maximum torque will be less than the peak torque, and this will be limited according to the motor's external characteristic curve. The fourth maximum output torque of the motor controller... It equals the external characteristic torque of the motor.

[0116] Step 205: Calculate the fifth maximum output torque based on the actual three-phase AC current output by the motor controller, including:

[0117] When a secondary over-temperature fault is triggered in the motor controller and the motor operating speed is greater than or equal to the speed at the field weakening point, the rated output three-phase AC current of the motor controller is obtained.

[0118] When the actual output three-phase AC current of the motor controller is greater than the sum of the rated output three-phase AC current and the second current threshold, the requested torque is reduced according to the sixth linear decreasing relationship until the actual output three-phase AC current of the motor controller is equal to the rated output three-phase AC current.

[0119] When the actual output three-phase AC current of the motor controller is greater than or equal to the difference between the rated output three-phase AC current and the second current threshold, and less than or equal to the sum of the rated output three-phase AC current and the second current threshold, the current output torque of the motor is taken as the fifth maximum output torque.

[0120] When the actual output three-phase AC current of the motor controller is less than the difference between the rated output three-phase AC current and the second current threshold, the maximum torque of the motor is taken as the fifth maximum output torque.

[0121] Since the core losses of a motor controller are the conduction and switching losses of the power devices (IGBTs), with conduction losses accounting for the largest proportion, and the conduction losses of IGBTs being directly proportional to the current, it is necessary to reduce the three-phase AC current of the motor controller when the temperature of the motor controller is too high. When the motor operating speed is greater than or equal to the field weakening point speed, the motor controller will generate a field weakening current to counteract the permanent magnet flux linkage and reduce the back electromotive force. At this time, operating the motor at 50% of its peak torque may not be enough to reduce the three-phase AC current of the motor controller to the rated current or below the rated current of the motor controller. It is necessary to further reduce the motor output torque to reduce the three-phase AC current of the motor controller.

[0122] Therefore, the maximum output torque of the motor controller is calculated based on the three-phase output AC current of the motor controller, including: when the motor controller is triggered by a secondary over-temperature fault, if the motor operating speed is greater than or equal to the preset field weakening point speed, the maximum output torque of the motor controller is calculated using the following formula:

[0123] ;

[0124] in, This indicates the fifth maximum output torque of the motor controller. This indicates the current output torque of the motor. This indicates the rated output three-phase AC current of the motor controller. This indicates the actual output three-phase AC current of the motor controller. This indicates the maximum torque of the motor. The preset current threshold can be adjusted according to the actual vehicle conditions to increase torque stability.

[0125] The principle is as follows: When a secondary over-temperature fault of the motor controller is triggered, if the actual output three-phase AC current of the motor controller is greater than the rated output three-phase AC current of the motor controller and exceeds a preset threshold, the vehicle controller linearly reduces the requested torque until the actual output three-phase AC current of the motor controller is approximately equal to the rated output three-phase AC current of the motor controller. When the actual output three-phase AC current of the motor controller fluctuates around the rated output three-phase AC current of the motor controller, the maximum output torque of the motor controller is equal to the current output torque of the motor. When the actual output three-phase AC current of the motor controller is less than the rated output three-phase AC current of the motor controller and exceeds a preset threshold, the maximum output torque of the motor controller is the maximum torque of the motor.

[0126] Step 206: Calculate the sixth maximum output torque based on the motor controller overload progress, including:

[0127] When the motor controller overload progress is greater than or equal to 50%, the sixth maximum output torque is determined according to the seventh linear decreasing relationship. The sixth maximum output torque Td6 = Tmax - (M - 0.5) × Tmax, where Tmax is the maximum torque of the motor and M is the motor controller overload progress.

[0128] When the motor controller overload is less than 50%, the motor's maximum torque is taken as the sixth maximum output torque.

[0129] The motor controller sends its overload progress information to the motor controller. To ensure a smoother torque limiting during fault protection, the maximum output torque of the motor controller needs to be calculated based on its overload progress. In this embodiment, this is expressed by the following formula:

[0130] ;

[0131] in, This indicates the sixth maximum output torque of the motor controller. This indicates the maximum torque of the motor. This indicates the overload level of the motor controller. For example, if the overload level of the motor controller is 60%, then the maximum output torque of the motor controller is 0.9 times the maximum torque of the motor.

[0132] Step 207: Calculate the seventh maximum output torque based on the motor controller fault level, including:

[0133] When the motor controller fault level is Level 1, the maximum torque of the motor is not limited;

[0134] When the motor controller fault level is level two, the maximum torque of the motor is partially limited.

[0135] When the motor controller fault level is three, the maximum torque of the motor will be limited to zero.

[0136] Specifically, when a motor controller malfunctions, the vehicle controller has a pre-defined mapping table between the motor controller's fault level and its maximum output torque. The maximum output torque of the motor controller is obtained by looking up this table. For example, currently, vehicle motor controllers have Level 1, Level 2, and Level 3 faults. When a motor controller malfunctions, the vehicle controller needs to send instructions according to the fault protection measures defined in the fault code table. A Level 1 motor controller fault typically does not require limiting the maximum output torque of the motor controller; a Level 2 motor controller fault typically requires limiting the maximum output torque of some motor controllers; and a Level 3 motor controller fault typically requires limiting the maximum output torque of the motor controller to 0.

[0137] Step 208: Select the minimum value from the first, second, third, fourth, fifth, sixth, and seventh maximum output torques as the requested torque limit value. Specifically: The vehicle controller compares the above seven maximum output torques and takes the minimum value as the limit value for the requested torque sent by the vehicle controller to the motor controller. Finally, based on the requested torque limit value, a torque control command is sent to the motor controller, which can greatly prevent damage to the motor controller due to overheating, overload, or other problems.

[0138] The methods in steps 201 to 208 optimize the motor over-temperature protection strategy from the traditional step torque limitation to a linear torque limitation, achieving a smooth torque transition and avoiding the problem of poor driving experience caused by a sudden drop in vehicle power. At the same time, the maximum output torque of the motor controller is comprehensively constrained from seven dimensions: motor temperature, motor controller temperature, battery distributable power, motor external characteristic curve, three-phase output AC current, overload progress, and fault level. The minimum value is taken as the final requested torque limit. This can achieve refined protection of the motor under various abnormal conditions such as insufficient battery power, motor or controller over-temperature, and overload, preventing damage to the motor controller due to exceeding the limit in a single dimension.

[0139] The vehicle control method of this invention further includes:

[0140] Obtain vehicle tilt angle and vehicle acceleration information;

[0141] The current road conditions are determined based on the vehicle's tilt angle. The current road conditions include uphill road conditions, downhill road conditions, and ordinary road conditions.

[0142] Determine the vehicle's load status based on vehicle acceleration information;

[0143] Based on the current road conditions and vehicle load status, determine the current operating conditions and adjust the control strategy of the motor controller accordingly.

[0144] The control strategy for adjusting the motor controller based on the current operating conditions includes:

[0145] When operating on an uphill slope, reduce the maximum torque that the vehicle controller can send to the motor controller.

[0146] When operating under normal road conditions, the maximum torque that the vehicle controller can send to the motor controller is equal to the torque request limit value.

[0147] When in downhill condition, if the duration of motor energy recovery exceeds the set value, the motor energy recovery and physical braking will be alternately activated in a cycle.

[0148] Different load conditions correspond to different throttle MAP curves, and the same throttle pedal depth corresponds to different requested torques.

[0149] Specifically, the vehicle tilt angle and acceleration are measured by slope and acceleration sensors and sent to the vehicle controller.

[0150] The vehicle controller determines the current road conditions and vehicle load status based on the vehicle's tilt angle and acceleration. When the vehicle tilt angle is positive and the duration exceeds the programmed judgment time, the vehicle is considered to be on an uphill road; when the vehicle tilt angle is negative and the duration exceeds the programmed judgment time, the vehicle is considered to be on a downhill road; when the vehicle tilt angle fluctuates around 0 degrees, if the peak tilt angle does not exceed the programmed value and the duration exceeds the programmed judgment time, the vehicle is considered to be on a normal road. Based on the vehicle's acceleration information, the vehicle controller can also analyze the current vehicle load status. Ultimately, considering both road conditions and load status, there are nine operating conditions: uphill unloaded, uphill half-loaded, uphill fully loaded, normal road unloaded, normal road half-loaded, normal road fully loaded, downhill unloaded, downhill half-loaded, and downhill fully loaded.

[0151] The vehicle controller adjusts the motor controller's control strategy based on the current operating conditions, namely the current road conditions and vehicle load status. In this embodiment, when the vehicle is uphill, the maximum requested torque of the motor controller is reduced; when the vehicle is on a normal road, the maximum requested torque of the motor controller is equal to the requested torque limit; when the vehicle is downhill, if the duration of motor energy recovery exceeds a set value, the vehicle controller controls the alternating intervention of motor energy recovery and physical braking to prevent the motor or motor controller from overheating or overloading, while also preventing the physical braking system from overheating.

[0152] When the vehicle is in different load states such as unloaded, half-loaded, and fully loaded, the vehicle controller adjusts to the corresponding throttle MAP curve. Under these different throttle MAPs, the same throttle pedal depth corresponds to different maximum power generation request torques of the motor controller.

[0153] During the process, the vehicle controller continuously determines whether the vehicle has performed a power-down operation. If a power-down operation is performed, the vehicle controller restores the motor controller control strategy to the default road condition and vehicle load state before going into sleep mode. If a power-down operation is not performed, the current operating conditions are analyzed and the current motor controller control strategy is executed.

[0154] The aforementioned method uses slope and acceleration sensors to measure the vehicle's tilt angle and acceleration in real time, enabling the vehicle controller to automatically identify three road conditions (uphill, ordinary road, and downhill) and four load states (empty, half-loaded, standard load / overloaded). These are combined to form nine refined operating conditions, and the control strategy is adaptively switched. During uphill operation, the maximum torque demand of the motor controller is actively reduced to match actual power requirements. On ordinary roads, a torque demand limit is applied. During downhill operation, if the energy recovery duration exceeds a set value, the motor's energy recovery and physical braking alternately and cyclically intervene, effectively preventing the motor or motor controller from overheating or overloading due to continuous energy recovery, while also avoiding overheating and failure of the physical braking system. Furthermore, different throttle MAP curves are matched for different load states, so that the same throttle pedal depth corresponds to different maximum torque demands of the motor controller under different loads. This achieves precise matching of pedal response and actual vehicle load, improving driving comfort and handling. The default control strategy is automatically restored before the vehicle is powered off, ensuring the system is in a known safe state upon the next power-on.

[0155] The present invention also provides a vehicle control device, comprising:

[0156] The acquisition module is used to acquire motor temperature, motor controller temperature, motor operating speed, motor controller input DC voltage, motor controller actual input DC current, motor controller actual output three-phase AC current, motor controller overload progress, and motor controller fault level.

[0157] The calculation module is used to calculate the first maximum output torque based on the motor temperature and motor operating speed, the second maximum output torque based on the motor controller temperature, the third maximum output torque based on the power that the current battery can allocate to the motor controller and the DC input voltage of the motor controller, the fourth maximum output torque based on the motor operating speed and motor external characteristic parameters, the fifth maximum output torque based on the actual three-phase AC current output by the motor controller, the sixth maximum output torque based on the overload progress of the motor controller, and the seventh maximum output torque based on the fault level of the motor controller.

[0158] The selection module is used to select the minimum value from the first maximum output torque to the seventh maximum output torque as the requested torque limit value;

[0159] The control module is used to send torque control commands to the motor controller based on the requested torque limit value.

[0160] In summary, this invention optimizes the step-like protection under abnormal conditions such as over-temperature and overload into a smooth transition through a multi-dimensional linear torque limiting method, avoiding sudden power changes and improving driving smoothness. It also provides comprehensive protection by taking the minimum value from seven constraint dimensions, effectively preventing damage to the motor controller. Through an adaptive working condition identification method using slope and acceleration sensors, it achieves accurate identification and strategy switching for nine road condition and load conditions. It reasonably limits torque when going uphill and alternates energy recovery and physical braking when going downhill to prevent system over-temperature and overload. It also matches the throttle MAP curves for different load states, significantly improving driving comfort, handling, and system safety.

[0161] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A vehicle control method, applied to a vehicle controller, characterized in that, include: The first maximum output torque is calculated based on the motor temperature and motor operating speed. The second maximum output torque is calculated based on the motor controller temperature. The third maximum output torque is calculated based on the power that the current battery can allocate to the motor controller and the DC input voltage of the motor controller; The fourth maximum output torque is calculated based on the motor's operating speed and external characteristic parameters. The fifth maximum output torque is calculated based on the actual three-phase AC current output by the motor controller. The sixth maximum output torque is calculated based on the overload progress of the motor controller; Calculate the seventh maximum output torque based on the motor controller fault level; Select the minimum value from the first to seventh maximum output torques mentioned above as the requested torque limit value; Based on the requested torque limit value, a torque control command is sent to the motor controller.

2. The method according to claim 1, characterized in that, The calculation of the first maximum output torque based on the motor temperature and motor operating speed includes: Obtain the secondary and tertiary over-temperature thresholds of the motor; When the motor temperature is less than the difference between the secondary over-temperature threshold and the preset first offset, the maximum torque of the motor is taken as the first maximum output torque. When the motor temperature is greater than or equal to the difference between the secondary over-temperature threshold and the preset first offset, and less than the secondary over-temperature threshold, the first maximum output torque is determined according to the first linear increasing relationship, and the first maximum output torque increases linearly from half of the peak torque to the maximum torque of the motor. When the motor temperature is greater than or equal to the secondary over-temperature threshold and less than the tertiary over-temperature threshold, the first maximum output torque is determined according to the second linear decreasing relationship, and the first maximum output torque decreases linearly from half of the peak torque to zero.

3. The method according to claim 1, characterized in that, The calculation of the second maximum output torque based on the motor controller temperature includes: Obtain the secondary and tertiary over-temperature thresholds of the motor controller; When the temperature of the motor controller is less than the difference between the secondary over-temperature threshold of the motor controller and the preset second offset, the maximum torque of the motor is taken as the second maximum output torque. When the temperature of the motor controller is greater than or equal to the difference between the secondary over-temperature threshold of the motor controller and the preset second offset, and less than the secondary over-temperature threshold of the motor controller, the second maximum output torque is determined according to the third linear increasing relationship, and the second maximum output torque increases linearly from half of the peak torque to the maximum torque of the motor. When the temperature of the motor controller is greater than or equal to the second-level over-temperature threshold of the motor controller and less than the third-level over-temperature threshold of the motor controller, the second maximum output torque is determined according to the fourth linear decreasing relationship, and the second maximum output torque decreases linearly from half of the peak torque to zero.

4. The method according to claim 1, characterized in that, The calculation of the third maximum output torque based on the power currently available to the motor controller from the battery and the DC input voltage of the motor controller includes: The power that the battery can currently allocate to the motor controller is obtained by subtracting the power of auxiliary drive appliances, thermal management appliances, and other appliances from the product of the battery bus voltage and the current maximum output current of the battery. The maximum input DC current of the motor controller is determined based on the ratio of the power that can be allocated to the motor controller to the input DC voltage of the motor controller. When the actual input DC current of the motor controller is greater than the sum of the maximum input DC current and the first current threshold, the requested torque is reduced according to the fifth linear decreasing relationship until the actual input DC current of the motor controller is equal to the maximum input DC current. When the actual input DC current of the motor controller is greater than or equal to the difference between the maximum input DC current and the first current threshold, and less than or equal to the sum of the maximum input DC current and the first current threshold, the current output torque of the motor is taken as the third maximum output torque. When the actual input DC current of the motor controller is less than the difference between the maximum input DC current and the first current threshold, the maximum torque of the motor is taken as the third maximum output torque.

5. The method according to claim 1, characterized in that, The calculation of the fourth maximum output torque based on the motor's operating speed and external characteristic parameters includes: When the operating speed of the motor is less than the speed at the weakening magnetic point, the motor is in the constant torque region, and the peak torque of the motor is taken as the fourth maximum output torque. When the operating speed of the motor is greater than or equal to the speed of the weakening magnetic point, the fourth maximum output torque is determined according to the external characteristic curve of the motor.

6. The method according to claim 1, characterized in that, The calculation of the fifth maximum output torque based on the actual output three-phase AC current of the motor controller includes: When a secondary over-temperature fault is triggered in the motor controller and the motor operating speed is greater than or equal to the speed at the weakening magnetic point, the rated output three-phase AC current of the motor controller is obtained. When the actual output three-phase AC current of the motor controller is greater than the sum of the rated output three-phase AC current and the second current threshold, the requested torque is reduced according to the sixth linear decreasing relationship until the actual output three-phase AC current of the motor controller is equal to the rated output three-phase AC current. When the actual output three-phase AC current of the motor controller is greater than or equal to the difference between the rated output three-phase AC current and the second current threshold, and less than or equal to the sum of the rated output three-phase AC current and the second current threshold, the current output torque of the motor is taken as the fifth maximum output torque. When the actual output three-phase AC current of the motor controller is less than the difference between the rated output three-phase AC current and the second current threshold, the maximum torque of the motor is taken as the fifth maximum output torque.

7. The method according to claim 1, characterized in that, The calculation of the sixth maximum output torque based on the overload progress of the motor controller includes: When the motor controller overload level is greater than or equal to 50%, the sixth maximum output torque is determined according to the seventh linear decreasing relationship, and the sixth maximum output torque is expressed as follows: ； in, This indicates the sixth maximum output torque of the motor controller. This indicates the maximum torque of the motor. Indicates the overload progress of the motor controller; When the overload progress of the motor controller is less than 50%, the maximum torque of the motor is taken as the sixth maximum output torque.

8. The method according to claim 1, characterized in that, The calculation of the seventh maximum output torque based on the motor controller fault level includes: When the motor controller fault level is Level 1, the maximum torque of the motor is not limited; When the motor controller fault level is level two, the maximum torque of the motor is partially limited; When the motor controller has a fault level of three, the maximum torque of the motor will be limited to zero.

9. The method according to any one of claims 1 to 8, characterized in that, Also includes: Obtain vehicle tilt angle and vehicle acceleration information; The current road conditions are determined based on the vehicle tilt angle, including uphill road conditions, downhill road conditions, and ordinary road conditions; The vehicle load status is determined based on the vehicle acceleration information. Based on the current road conditions and the vehicle load status, determine the current operating condition, and adjust the control strategy of the motor controller based on the current operating condition; The control strategy for adjusting the motor controller based on the current operating conditions includes: When operating on an uphill slope, reduce the maximum torque that the vehicle controller can send to the motor controller. When operating under normal road conditions, the maximum power generation request torque that the vehicle controller can send to the motor controller is equal to the requested torque limit value; When in downhill condition, if the duration of motor energy recovery exceeds the set value, the motor energy recovery and physical braking will be alternately activated in a cycle. Different load conditions correspond to different throttle MAP curves, and the same throttle pedal depth corresponds to different requested torques.

10. A vehicle control device, characterized in that, include: The acquisition module is used to acquire motor temperature, motor controller temperature, motor operating speed, motor controller input DC voltage, motor controller actual input DC current, motor controller actual output three-phase AC current, motor controller overload progress, and motor controller fault level. The calculation module is used to calculate a first maximum output torque based on the motor temperature and the motor operating speed, a second maximum output torque based on the motor controller temperature, a third maximum output torque based on the power that the current battery can allocate to the motor controller and the DC input voltage of the motor controller, a fourth maximum output torque based on the motor operating speed and the motor external characteristic parameters, a fifth maximum output torque based on the actual three-phase AC current output by the motor controller, a sixth maximum output torque based on the overload progress of the motor controller, and a seventh maximum output torque based on the fault level of the motor controller. The selection module is used to select the minimum value from the first maximum output torque to the seventh maximum output torque as the requested torque limit value; The control module is used to send torque control commands to the motor controller based on the requested torque limit value.

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