Vehicle, power assembly system of vehicle and overheating protection method of power assembly system

Abstract

The invention discloses a vehicle, a power assembly system of the vehicle and an overheating protection method of the power assembly system. A powertrain system of a vehicle includes at least one powertrain and a master controller. Each power system comprises a sub-controller and a permanent magnet synchronous motor, the sub-controller sends an effective speed limiting request when the power system enters a first state and the temperature rise condition of the permanent magnet synchronous motor and / or the sub-controller meets the temperature rise condition, and the first state is that the temperature of the permanent magnet synchronous motor and / or the sub-controller is larger than or equal to a first temperature threshold value; the permanent magnet synchronous motor enters torque limiting operation and does not stop rotating; the total controller determines the target speed of the vehicle according to the maximum allowable rotating speed under the condition that the effective speed limiting request is received, the vehicle is controlled to slow down to the target speed, the second state is that the permanent magnet synchronous motor is in a field weakening control mode, and the temperature rise condition of the permanent magnet synchronous motor and / or the sub-controller meets the temperature rise condition. The problem that the power device of the power system is damaged by over-temperature can be avoided.

Description

Technical Field

[0001] This application belongs to the field of vehicle technology, and in particular relates to a vehicle, a vehicle powertrain system, and an overheat protection method thereof. Background Technology

[0002] The safe operation of a vehicle's powertrain is crucial for its safety and stability. Overheating of the powertrain can damage power components, making overheat protection necessary. Current technologies typically involve reducing the torque of the powertrain motor when its temperature exceeds a certain threshold; however, this method is insufficient for effective overheat protection. Summary of the Invention

[0003] The embodiments of this application provide a vehicle, a powertrain system of the vehicle, and an overheat protection method thereof, which can at least to some extent avoid the problem that after a permanent magnet synchronous motor enters the field weakening control mode, the field weakening current rises, causing the temperature of the power devices in the power system to rise and thus damaging the power devices, thereby ensuring the safe operation of the power system.

[0004] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0005] The first aspect of this application provides a powertrain system for a vehicle, comprising:

[0006] At least one power system, each power system including a sub-controller and a permanent magnet synchronous motor, the sub-controller being configured to: after the power system enters a first state, when the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets a preset temperature rise condition, send an effective speed limit request, wherein the first state is when the temperature of the permanent magnet synchronous motor and / or the sub-controller is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor enters a torque-limited operation state and the permanent magnet synchronous motor has not stopped rotating;

[0007] A main controller, communicatively connected to the sub-controllers, is configured to: upon receiving the valid speed limit request, acquire the maximum permissible speed of the permanent magnet synchronous motor in a second state, determine the target vehicle speed based on the maximum permissible speed, and control the vehicle to decelerate to the target vehicle speed. The second state is when the permanent magnet synchronous motor is in a field weakening control mode, and the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the temperature rise condition.

[0008] Optionally, the main controller is further configured to: receive a speed limit request carrying a signal value sent by the sub-controller, and determine whether the speed limit request is a valid speed limit request based on the signal value.

[0009] Optionally, when obtaining the maximum permissible speed of the permanent magnet synchronous motor in the second state, the main controller is further configured to:

[0010] Receive the maximum permissible speed of the permanent magnet synchronous motor in the second state sent by the sub-controller; or

[0011] In the second state, the back electromotive force generated by the permanent magnet synchronous motor at a reference speed is obtained, and the maximum allowable speed is determined based on the back electromotive force.

[0012] Optionally, the sub-controller is further configured to:

[0013] In the second state, the back electromotive force generated by the permanent magnet synchronous motor at a reference speed is obtained, and the maximum allowable speed is determined based on the back electromotive force.

[0014] Optionally, the vehicle further includes a power battery, and the maximum permissible rotational speed is determined based on the following:

[0015] Obtain the voltage of the power battery and determine the product between the voltage of the power battery and the reference speed of the permanent magnet synchronous motor;

[0016] The maximum permissible rotational speed is determined based on the ratio between the product and the back electromotive force.

[0017] Optionally, the preset temperature rise conditions include:

[0018] The permanent magnet synchronous motor and / or the sub-controller have a first temperature at a first moment that is greater than a second temperature at a second moment, the temperature difference between the first temperature and the second temperature is greater than or equal to a preset temperature difference threshold, the first moment is later than the second moment, and the second moment is the moment when the power system enters the first state; or

[0019] The temperature of the permanent magnet synchronous motor and / or the sub-controller is greater than or equal to a second temperature threshold, wherein the second temperature threshold is greater than the first temperature threshold.

[0020] A second aspect of this application provides an overheat protection method for a vehicle's powertrain system. The powertrain system includes a main controller and at least one power system, each power system including a sub-controller and a permanent magnet synchronous motor. The method is executed on the main controller and includes:

[0021] Upon receiving the effective speed limit request, the maximum permissible speed of the permanent magnet synchronous motor in the second state is obtained; wherein, the effective speed limit request is sent by the sub-controller after the power system enters the first state, when the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets a preset temperature rise condition, the first state is when the temperature of the permanent magnet synchronous motor and / or the sub-controller is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor enters a torque-limited operation state and the permanent magnet synchronous motor has not stopped rotating, and the second state is when the permanent magnet synchronous motor is in a field-weakening control mode and the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the temperature rise condition;

[0022] The target vehicle speed is determined based on the maximum permissible rotational speed.

[0023] Control the vehicle to decelerate to the target speed.

[0024] Optionally, the vehicle further includes a human-machine interface module and vehicle lights, and when controlling the vehicle to decelerate to the target speed, the method further includes:

[0025] The human-computer interaction module outputs alarm prompts; and / or

[0026] Control the vehicle lights to flash as a warning.

[0027] A third aspect of this application provides an overheat protection device for a vehicle's powertrain system. The powertrain system includes a main controller and at least one power system, each power system including a sub-controller and a permanent magnet synchronous motor. The device is disposed on the main controller and includes:

[0028] The acquisition unit is used to acquire the maximum permissible speed of the permanent magnet synchronous motor in the second state upon receiving the effective speed limit request; wherein the effective speed limit request is sent by the sub-controller after the power system enters the first state, when the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets a preset temperature rise condition, the first state is when the temperature of the permanent magnet synchronous motor and / or the sub-controller is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor enters torque-limited operation and the permanent magnet synchronous motor has not stopped rotating, and the second state is when the permanent magnet synchronous motor is in a field-weakening control mode and the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the temperature rise condition;

[0029] A determining unit is configured to determine the target vehicle speed based on the maximum permissible rotational speed;

[0030] The control unit is used to control the vehicle to decelerate to the target speed.

[0031] A fourth aspect of this application provides an overheat protection method for a vehicle's powertrain system. The powertrain system includes a main controller and at least one power system, each power system including a sub-controller and a permanent magnet synchronous motor. The method is executed on the sub-controller and includes:

[0032] After the power system enters the first state, when the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the preset temperature rise condition, a valid speed limit request is sent so that the main controller, upon receiving the valid speed limit request, obtains the maximum allowable speed of the permanent magnet synchronous motor in the second state, determines the target speed of the vehicle based on the maximum allowable speed, and controls the vehicle to decelerate to the target speed.

[0033] The first state is when the temperature of the permanent magnet synchronous motor and / or the sub-controller is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor enters a torque-limited operation and the permanent magnet synchronous motor does not stop rotating, and the second state is when the permanent magnet synchronous motor is in a field-weakening control mode and the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the temperature rise condition.

[0034] Optionally, the method further includes:

[0035] After the power system enters the first state, if the speed of the permanent magnet synchronous motor is greater than or equal to the preset field weakening control mode speed, then the permanent magnet synchronous motor is controlled to enter the field weakening control mode.

[0036] A fifth aspect of this application provides an overheat protection device for a vehicle's powertrain system. The powertrain system includes a main controller and at least one power system, each power system including a sub-controller and a permanent magnet synchronous motor. The device is disposed on the sub-controller and includes:

[0037] The sending unit is configured to send a valid speed limit request after the power system enters the first state, when the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the preset temperature rise conditions, so that the main controller can obtain the maximum allowable speed of the permanent magnet synchronous motor in the second state upon receiving the valid speed limit request, determine the target speed of the vehicle based on the maximum allowable speed, and control the vehicle to decelerate to the target speed.

[0038] The first state is when the temperature of the permanent magnet synchronous motor and / or the sub-controller is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor enters a torque-limited operation and the permanent magnet synchronous motor does not stop rotating, and the second state is when the permanent magnet synchronous motor is in a field-weakening control mode and the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the temperature rise condition.

[0039] A sixth aspect of this application provides a vehicle including a powertrain system as described in any of the first aspects.

[0040] Optionally, the at least one power system includes: a front-drive motor system, a rear-drive motor system, and a generator system;

[0041] The vehicle also includes: front wheels, rear wheels, and an engine. The front wheels are connected to the permanent magnet synchronous motor of the front drive motor system, the rear wheels are connected to the permanent magnet synchronous motor of the rear drive motor system, and the engine is connected to the permanent magnet synchronous motor of the generator system.

[0042] A seventh aspect of this application provides an electronic device, one or more processors, and one or more memories, wherein at least one piece of program code is stored in the one or more memories, and the at least one piece of program code is loaded and executed by the one or more processors to perform the operation performed by any method described in the second aspect, or to perform the operation performed by any method described in the fourth aspect.

[0043] An eighth aspect of this application provides a computer-readable storage medium storing at least one computer program instruction, which is loaded and executed by a processor to perform the operation as described in any of the methods in the second aspect or any of the methods in the fourth aspect.

[0044] The embodiments of the present invention provide one or more technical solutions that achieve at least the following technical effects or advantages:

[0045] The powertrain system of a vehicle according to an embodiment of this application includes: at least one powertrain system and a main controller. Each powertrain system includes a sub-controller and a permanent magnet synchronous motor. The sub-controller is configured to: after the powertrain system enters a first state, when the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets a preset temperature rise condition, send a valid speed limit request. The first state is when the temperature of the permanent magnet synchronous motor and / or the sub-controller is greater than or equal to a preset first temperature threshold, and the permanent magnet synchronous motor enters a torque-limited operation state without stopping rotation. The main controller is communicatively connected to the sub-controller. The main controller is configured to: upon receiving a valid speed limit request, obtain the maximum permissible speed of the permanent magnet synchronous motor in a second state, determine the target vehicle speed based on the maximum permissible speed, and control the vehicle to decelerate to the target vehicle speed. The second state is when the permanent magnet synchronous motor is in a field-weakening control mode, and the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the temperature rise condition.

[0046] Therefore, in this embodiment of the application, when the permanent magnet synchronous motor of the power system enters the torque-limited operation but has not stopped rotating, and then enters the field-weakening control mode, the vehicle is controlled to decelerate when the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the temperature rise condition. This avoids the problem that the field-weakening current rises after the permanent magnet synchronous motor enters the field-weakening control mode, which would cause the temperature of the power devices in the power system to rise and thus damage the power devices, thereby ensuring the safe operation of the power system.

[0047] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0048] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0049] Figure 1 A structural block diagram of the powertrain system of a vehicle according to an embodiment of this application is shown;

[0050] Figure 2 A flowchart illustrating an overheat protection method for a vehicle's powertrain system according to an embodiment of this application is shown.

[0051] Figure 3 A structural block diagram of an overheat protection device for a vehicle's powertrain system, according to an embodiment of this application, is shown.

[0052] Figure 4Another flowchart of an overheat protection method for a vehicle powertrain system according to an embodiment of this application is shown;

[0053] Figure 5 Another structural block diagram of an overheat protection device for a vehicle's powertrain system, according to an embodiment of this application, is shown.

[0054] Figure 6 Another flowchart of an overheat protection method for a powertrain system according to an embodiment of this application is shown;

[0055] Figure 7 A schematic diagram of the communication architecture of a vehicle according to an embodiment of this application is shown;

[0056] Figure 8 A schematic diagram of the structure of a computer system suitable for implementing the electronic device of the present application is shown.

[0057] 100-Powertrain system; 10-Power system; 11-Sub-controller; 12-Permanent magnet synchronous motor; 13-Front drive motor system; 14-Rear drive motor system; 15-Generator system; 20-Main controller; 30-Power battery system; 40-Engine system; 50-User reminder interface; 60-Follow-the-car reminder window. Detailed Implementation

[0058] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0059] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0060] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different models and / or processor devices and / or microcontroller devices.

[0061] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0062] It should also be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such uses of these terms can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described.

[0063] With the advancement of new energy vehicle development and product technology, new energy four-wheel drive models have emerged. Four-wheel drive vehicles have improved in terms of handling and stability, but they also place higher demands on the safety and reliability of the powertrain system. Overheating of the powertrain system may damage power devices, so it is necessary to implement overheat protection for the powertrain system.

[0064] The powertrain system of a new energy four-wheel drive vehicle mainly includes a main controller and at least one power system. The power system can be at least one of a front drive motor and its sub-controller, a rear drive motor and its sub-controller, and a generator and its sub-controller. In related technologies, when the temperature of the power system exceeds a temperature threshold, the motors in the power system are typically controlled to reduce torque, thereby providing overheat protection for the power system. For example, when the temperature of the front drive motor is greater than or equal to the temperature threshold, the torque of the front drive motor is limited to zero; similarly, when the temperature of the rear drive motor is greater than or equal to the temperature threshold, the torque of the rear drive motor is limited to zero; and again, when the temperature of the generator is greater than or equal to the temperature threshold, the torque of the generator is limited to zero.

[0065] However, the relevant technologies cannot effectively protect the powertrain from overheating because: currently, the motors in powertrains typically use permanent magnet synchronous motors (PMSMs). When the temperature of the powertrain exceeds or equals a temperature threshold, the PMSM enters reduced torque operation, for example, the torque drops to zero. However, since the PMSM is mechanically connected to the wheels or engine, even if the torque of the PMSM drops to zero, the wheels and engine are still running (rotating), driving the PMSM to rotate. The motor speed increases with vehicle speed. After exceeding a certain speed, the powertrain enters a field weakening control mode. The stronger the field weakening control, the greater the field weakening current, which causes the temperature of power devices (such as the coils of the PMSM and the transistors of the sub-controller) to continue to rise, leading to the burnout of power devices and affecting vehicle operating safety.

[0066] In view of this, the present application provides a powertrain system for a vehicle that can, to a certain extent, avoid the problem that the weakening current rises after the permanent magnet synchronous motor enters the field weakening control mode, causing the temperature of the power devices in the power system to rise and thus damaging the power devices, thereby ensuring the safe operation of the power system.

[0067] The powertrain system of the vehicle according to an embodiment of this application will now be described with reference to the accompanying drawings.

[0068] Figure 1 A structural block diagram of a vehicle powertrain system 100 according to an embodiment of this application is shown.

[0069] The first aspect of this application provides a powertrain system 100 for a vehicle, including at least one powertrain system 10 and a main controller 20. Each of the power systems 10 includes a sub-controller 11 and a permanent magnet synchronous motor 12. The sub-controller 11 is configured to send an effective speed limit request after the power system 10 enters a first state, when the temperature rise of the permanent magnet synchronous motor 12 and / or the sub-controller 11 meets a preset temperature rise condition. The first state is when the temperature of the permanent magnet synchronous motor 12 and / or the sub-controller 11 is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor 12 enters a torque-limited operation state, and the permanent magnet synchronous motor 12 has not stopped rotating. The main controller 20 is communicatively connected to the sub-controller 11. The main controller 20 is configured to: upon receiving the effective speed limit request, obtain the maximum allowable speed of the permanent magnet synchronous motor 12 in a second state, determine the target vehicle speed based on the maximum allowable speed, and control the vehicle to decelerate to the target vehicle speed. The second state is when the permanent magnet synchronous motor 12 is in a weak field control mode, and the temperature rise of the permanent magnet synchronous motor 12 and / or the sub-controller 11 meets the temperature rise condition.

[0070] In some embodiments, the main controller 20 may be a vehicle controller, such as a VCU.

[0071] In some embodiments, the at least one power system 10 includes: a front drive motor system 13, a rear drive motor system 14, and a generator system 15.

[0072] When the temperature of the permanent magnet synchronous motor 12 and / or the sub-controller 11 of the power system 10 is greater than or equal to a first temperature threshold, the sub-controller 11 will control the permanent magnet synchronous motor 12 to limit torque, for example, reduce the torque to 0, thereby preventing the temperature of the power system 10 from continuing to rise and thus damaging the components. The first temperature threshold can be set according to the actual needs of the vehicle application, for example, it can be 100 degrees Celsius, 105 degrees Celsius, 110 degrees Celsius, etc., and is not limited here.

[0073] In a vehicle, the front-drive or rear-drive motor is mechanically connected to the wheels, and the generator is mechanically connected to the engine. The wheels can continue to run even after the torque of the front-drive or rear-drive motor has been limited, and the engine can continue to run even after the torque of the generator has been limited. Therefore, the front-drive or rear-drive motor will continue to rotate under the drive of the wheels, and the generator may also continue to rotate under the drive of the engine. Consequently, even after the torque of the permanent magnet synchronous motor 12 in each power system 10 is reduced to zero, it can still be driven to rotate, thereby generating a back electromotive force. Furthermore, the output power of the motor's sub-controller 11 is not zero. After the permanent magnet synchronous motor 12 exceeds a certain speed, the system performs field weakening control. The greater the intensity of the field weakening control, the greater the field weakening current, which causes the temperature of the power devices to rise continuously, potentially leading to the burnout of the power devices and posing a risk of vehicle fire.

[0074] It should be noted that the field weakening control principle of the permanent magnet synchronous motor 12 is a control strategy that weakens the air gap magnetic field by adjusting the direct-axis current when the motor speed exceeds the base speed. As the motor speed increases, the back electromotive force increases linearly with the speed. Without control, this will exceed the inverter's DC bus voltage limit, preventing further speed increases. The core of field weakening control is to inject a negative direct-axis current (-id) to generate an armature reaction magnetic field opposite to the direction of the permanent magnet magnetic field, thereby reducing the equivalent air gap flux linkage. In terms of control implementation, the voltage limit constraint condition must be met, i.e., the magnitude of the stator voltage vector must not exceed the inverter's maximum output voltage. By establishing a control algorithm based on the voltage limit ellipse and the current limit circle, the distribution of the direct-axis current and quadrature-axis current is dynamically adjusted in the high-speed region, enabling the motor to continue operating under voltage constraints.

[0075] Therefore, field weakening control requires additional current for control. Increased current will increase the power losses of the power devices of the permanent magnet synchronous motor 12 and / or the sub-controller 11, thereby causing the motor and sub-controller 11 to overheat. Based on this, the embodiments of this application calibrate the temperature rise conditions. After the power system 10 enters the first state, when the temperature rise of the permanent magnet synchronous motor 12 and / or the sub-controller 11 meets the preset temperature rise conditions, an effective speed limit request is sent to the main controller 20. After receiving the effective speed limit request, the main controller 20 decelerates the vehicle, thereby reducing the speed of the permanent magnet synchronous motor 12 and thus reducing the current of the permanent magnet synchronous motor 12, thereby providing overheat protection for the permanent magnet synchronous motor 12 and the sub-controller 11.

[0076] In some embodiments, the main controller 20 is further configured to: receive a speed limit request carrying a signal value sent by the sub-controller 11, and determine whether the speed limit request is a valid speed limit request based on the signal value.

[0077] It is understandable that the sub-controller 11 can periodically send speed limit requests to the main controller 20, thereby enabling the main controller 20 to know whether the communication status with the sub-controller 11 is normal. However, each speed limit request sent by the sub-controller 11 is not necessarily valid. The validity of the speed limit request can be characterized by the signal value carried in the speed limit request. For example, when the signal value = 1, the speed limit request is a valid speed limit request; when the signal value = 0, the speed limit request is an invalid speed limit request. In this embodiment, after the power system 10 enters the first state, the sub-controller 11 sends a valid speed limit request when the temperature rise of the permanent magnet synchronous motor 12 and / or the sub-controller 11 meets the preset temperature rise condition; the sub-controller 11 sends an invalid speed limit request in other situations.

[0078] In some embodiments, when obtaining the maximum permissible speed of the permanent magnet synchronous motor 12 in the second state, the total controller 20 is further configured to:

[0079] Receive the maximum permissible speed of the permanent magnet synchronous motor 12 in the second state sent by the sub-controller 11; or

[0080] The back electromotive force generated by the permanent magnet synchronous motor 12 at a reference speed in the second state is obtained, and the maximum allowable speed is determined based on the back electromotive force.

[0081] It should be noted that the maximum permissible speed of the permanent magnet synchronous motor 12 in the second state can refer to the maximum speed at which the permanent magnet synchronous motor 12 will not cause the temperature to continue to rise in the second state.

[0082] In other words, the sub-controller 11 can independently determine the maximum permissible speed of the permanent magnet synchronous motor 12 and then send it to the main controller 20; the main controller 20 can also determine the maximum permissible speed by acquiring the back electromotive force generated by the permanent magnet synchronous motor 12 at a reference speed and based on the back electromotive force. The specific method can be determined according to actual needs and is not limited here.

[0083] In some embodiments, the sub-controller 11 is further configured to:

[0084] The back electromotive force generated by the permanent magnet synchronous motor 12 at a reference speed in the second state is obtained, and the maximum allowable speed is determined based on the back electromotive force.

[0085] In some embodiments, the vehicle further includes a power battery, and the maximum permissible rotational speed is determined based on the following:

[0086] Obtain the voltage of the power battery and determine the product between the voltage of the power battery and the reference speed of the permanent magnet synchronous motor 12;

[0087] The maximum permissible rotational speed is determined based on the ratio between the product and the back electromotive force.

[0088] For example, the reference speed can refer to the speed at which the permanent magnet synchronous motor 12 and / or the sub-controller 11 meet preset temperature rise conditions after the power system 10 enters the first state, or it can be the speed used to test the back electromotive force during calibration. No limitation is made here. For example, the value of the reference speed can be 2000, 3000, 4000, 5000, etc., without limitation.

[0089] For ease of understanding, the following formula describes how to determine the maximum permissible speed:

[0090] Nmax = V × nref / Eref;

[0091] Where Nmax represents the maximum permissible speed, V represents the voltage of the power battery, nref represents the reference speed, and Eref represents the back electromotive force generated by the permanent magnet synchronous motor 12 at the reference speed.

[0092] Understandably, in the field-weakening control mode of the permanent magnet synchronous motor 12, the relationship between back electromotive force (EMF) and speed can be expressed as follows: below the base speed, the back EMF increases linearly with increasing speed, and its magnitude is determined by both the permanent magnet flux linkage and the speed, following the formula E = ke × ω, where ke is the back EMF constant and ω represents the angular velocity. When the speed exceeds the base speed and enters the field-weakening region, the air gap magnetic field is actively weakened by applying a negative direct-axis current (-id), causing the equivalent flux linkage ψ = ψf - Ld × id to decrease. At this time, the growth trend of the back EMF is suppressed. Although it still increases with increasing speed, the rate of increase slows down significantly, and its expression is modified to E ≈ (ψf - Ld × id) × ω. By adjusting id in real time, the back EMF can be controlled within the inverter voltage limit range. Therefore, the back EMF can be determined by referring to the speed.

[0093] In some embodiments, the preset temperature rise conditions include:

[0094] The permanent magnet synchronous motor 12 and / or the sub-controller 11 have a first temperature at a first moment that is greater than a second temperature at a second moment, the temperature difference between the first temperature and the second temperature is greater than or equal to a preset temperature difference threshold, the first moment is later than the second moment, and the second moment is the moment when the power system 10 enters the first state; or

[0095] The temperature of the permanent magnet synchronous motor 12 and / or the sub-controller 11 is greater than or equal to a second temperature threshold, wherein the second temperature threshold is greater than the first temperature threshold.

[0096] For example, at the second moment when the power system 10 enters the first state, the temperature of the permanent magnet synchronous motor 12 and / or the sub-controller 11 is 100 degrees Celsius. After a period of time, such as after 1 minute, 5 minutes, or 10 minutes, the temperature of the permanent magnet synchronous motor 12 and / or the sub-controller 11 at the first moment is 120 degrees, 130 degrees, 140 degrees, 150 degrees, etc. The temperature difference between the two moments exceeds the preset temperature difference threshold, such as 10 degrees, 15 degrees, 20 degrees, etc., thereby satisfying the preset temperature rise condition.

[0097] For example, after the power system 10 enters the first state, the temperature of the power system 10 continues to be detected. When the temperature of the permanent magnet synchronous motor 12 and / or the sub-controller 11 is greater than or equal to the second temperature threshold, such as 120 degrees, 130 degrees, 140 degrees, or 150 degrees, the preset temperature rise condition is met.

[0098] Understandably, the relationship between vehicle speed and the rotational speed of the permanent magnet synchronous motor 12 is mainly determined by the mechanical connection method and reduction ratio of the transmission system. For electric vehicle drive systems using a fixed reduction ratio, the motor speed and vehicle speed have a linear proportional relationship, expressed mathematically as v = (2πr·ω_m·i_0) / (60×3.6), where r is the wheel rolling radius (in meters) and i_0 is the total reduction ratio of the transmission system (including the gearbox ratio and the final drive ratio). This formula shows that when the transmission ratio is fixed, the vehicle speed is directly proportional to the motor speed. Therefore, given the maximum permissible speed of the motor, the target speed of the vehicle can be determined based on the proportional relationship, thereby controlling the vehicle to decelerate to that target speed.

[0099] Figure 2 A flowchart of an overheat protection method for a vehicle powertrain system 100 according to an embodiment of this application is shown.

[0100] A second aspect of this application provides an overheat protection method for a vehicle powertrain system 100, the powertrain system 100 including a main controller 20 and at least one powertrain system 10, each powertrain system 10 including a sub-controller 11 and a permanent magnet synchronous motor 12, the method being executed on the main controller 20, the method comprising:

[0101] Step S101. Upon receiving the effective speed limit request, obtain the maximum permissible speed of the permanent magnet synchronous motor 12 in the second state; wherein, the effective speed limit request is sent by the sub-controller 11 after the power system 10 enters the first state, when the temperature rise of the permanent magnet synchronous motor 12 and / or the sub-controller 11 meets a preset temperature rise condition, the first state is when the temperature of the permanent magnet synchronous motor 12 and / or the sub-controller 11 is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor 12 enters a torque-limited operation state and the permanent magnet synchronous motor 12 has not stopped rotating, and the second state is when the permanent magnet synchronous motor 12 is in a field-weakening control mode, and the temperature rise of the permanent magnet synchronous motor 12 and / or the sub-controller 11 meets the temperature rise condition;

[0102] Step S102. Determine the target vehicle speed based on the maximum permissible rotational speed;

[0103] Step S103. Control the vehicle to decelerate to the target speed.

[0104] In some embodiments, obtaining the maximum permissible speed of the permanent magnet synchronous motor 12 in the second state includes:

[0105] Receive the maximum permissible speed of the permanent magnet synchronous motor 12 in the second state sent by the sub-controller 11; or

[0106] The back electromotive force generated by the permanent magnet synchronous motor 12 at a reference speed in the second state is obtained, and the maximum allowable speed is determined based on the back electromotive force.

[0107] In some embodiments, the vehicle further includes a human-machine interface module and vehicle lights, and when controlling the vehicle to decelerate to the target speed, the method further includes:

[0108] The human-computer interaction module outputs alarm prompts; and / or

[0109] Control the vehicle lights to flash as a warning.

[0110] In some embodiments, the human-machine interaction module includes, but is not limited to: a user prompt interface, a following reminder window 60, indicator lights, a voice module, etc., which output alarm prompt information in one or more ways to remind the user that there is an abnormality in the vehicle and to pay attention to safety, such as reminding the driver of the current speed limit value through the instrument panel pop-up, reminding the user to go to the store for maintenance, etc.

[0111] In some embodiments, controlling the vehicle lights to flash as a warning may involve controlling the taillights to flash, thereby alerting surrounding personnel that there is an abnormality with the vehicle and requesting them to maintain a safe distance or take evasive action.

[0112] Figure 3 A structural block diagram of an overheat protection device for a vehicle powertrain system 100 according to an embodiment of this application is shown.

[0113] A third aspect of this application provides an overheat protection device 200 for a vehicle powertrain system 100. The powertrain system 100 includes a main controller 20 and at least one powertrain system 10. Each powertrain system 10 includes a sub-controller 11 and a permanent magnet synchronous motor 12. The device is disposed on the main controller 20. The device 200 includes:

[0114] The acquisition unit 201 is used to acquire the maximum permissible speed of the permanent magnet synchronous motor 12 in the second state when the effective speed limit request is received; wherein, the effective speed limit request is sent by the sub-controller 11 after the power system 10 enters the first state, when the temperature rise of the permanent magnet synchronous motor 12 and / or the sub-controller 11 meets a preset temperature rise condition, the first state is when the temperature of the permanent magnet synchronous motor 12 and / or the sub-controller 11 is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor 12 enters a torque-limited operation state and the permanent magnet synchronous motor 12 has not stopped rotating, and the second state is when the permanent magnet synchronous motor 12 is in a field-weakening control mode and the temperature rise of the permanent magnet synchronous motor 12 and / or the sub-controller 11 meets the temperature rise condition;

[0115] Determining unit 202 is used to determine the target vehicle speed based on the maximum permissible rotational speed;

[0116] Control unit 203 is used to control the vehicle to decelerate to the target speed.

[0117] In some embodiments, when obtaining the maximum permissible speed of the permanent magnet synchronous motor 12 in the second state, the obtaining unit 201 is specifically used for:

[0118] Receive the maximum permissible speed of the permanent magnet synchronous motor 12 in the second state sent by the sub-controller 11; or

[0119] The back electromotive force generated by the permanent magnet synchronous motor 12 at a reference speed in the second state is obtained, and the maximum allowable speed is determined based on the back electromotive force.

[0120] In some embodiments, the vehicle further includes a human-machine interface module and vehicle lights, and when controlling the vehicle to decelerate to the target speed, the device 200 is further configured to:

[0121] The human-computer interaction module outputs alarm prompts; and / or

[0122] Control the vehicle lights to flash as a warning.

[0123] Figure 4 Another flowchart of an overheat protection method for a vehicle powertrain system 100 according to an embodiment of this application is shown.

[0124] A fourth aspect of this application provides an overheat protection method for a vehicle powertrain system 100. The powertrain system 100 includes a main controller 20 and at least one powertrain system 10. Each powertrain system 10 includes a sub-controller 11 and a permanent magnet synchronous motor 12. The method is executed on the sub-controller 11 and includes, but is not limited to:

[0125] Step S301. After the power system 10 enters the first state, when the temperature rise of the permanent magnet synchronous motor 12 and / or the sub-controller 11 meets the preset temperature rise condition, a valid speed limit request is sent so that the main controller 20, upon receiving the valid speed limit request, obtains the maximum allowable speed of the permanent magnet synchronous motor 12 in the second state, determines the target speed of the vehicle based on the maximum allowable speed, and controls the vehicle to decelerate to the target speed.

[0126] The first state is when the temperature of the permanent magnet synchronous motor 12 and / or the sub-controller 11 is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor 12 enters a torque-limited operation state and the permanent magnet synchronous motor 12 does not stop rotating, and the second state is when the permanent magnet synchronous motor 12 is in a field-weakening control mode and the temperature rise of the permanent magnet synchronous motor 12 and / or the sub-controller 11 meets the temperature rise condition.

[0127] Step S302. In some embodiments, the method further includes:

[0128] After the power system 10 enters the first state, if the speed of the permanent magnet synchronous motor 12 is greater than or equal to the preset field weakening control mode speed, then the permanent magnet synchronous motor 12 is controlled to enter the field weakening control mode.

[0129] Figure 5 Another structural block diagram of an overheat protection device for a vehicle powertrain system 100 according to an embodiment of this application is shown.

[0130] A fifth aspect of this application provides an overheat protection device 600 for a vehicle powertrain system 100. The powertrain system 100 includes a main controller 20 and at least one powertrain system 10. Each powertrain system 10 includes a sub-controller 11 and a permanent magnet synchronous motor 12. The device 600 is disposed on the sub-controller 11 and includes:

[0131] The sending unit 601 is configured to send a valid speed limit request after the power system 10 enters the first state, when the temperature rise of the permanent magnet synchronous motor 12 and / or the sub-controller 11 meets the preset temperature rise conditions, so that the main controller 20, upon receiving the valid speed limit request, obtains the maximum allowable speed of the permanent magnet synchronous motor 12 in the second state, determines the target speed of the vehicle based on the maximum allowable speed, and controls the vehicle to decelerate to the target speed;

[0132] The first state is when the temperature of the permanent magnet synchronous motor 12 and / or the sub-controller 11 is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor 12 enters a torque-limited operation state and the permanent magnet synchronous motor 12 does not stop rotating, and the second state is when the permanent magnet synchronous motor 12 is in a field-weakening control mode and the temperature rise of the permanent magnet synchronous motor 12 and / or the sub-controller 11 meets the temperature rise condition.

[0133] In some embodiments, the device 600 further includes:

[0134] The field weakening control unit 602 is used to control the permanent magnet synchronous motor 12 to enter the field weakening control mode after the power system 10 enters the first state if the speed of the permanent magnet synchronous motor 12 is greater than or equal to the preset field weakening control mode speed.

[0135] Figure 6 Another flowchart of an overheat protection method for a powertrain system 100 according to an embodiment of this application is shown.

[0136] like Figure 6 As shown, after the vehicle is powered on and awakened, if the voltage VBAT of the high-voltage power battery system 30 is greater than 9V, the sub-control MCUs of each power system 10 are initialized, and VBAT is sampled again. If 9V < VBAT < 16V, the temperature of the power system 10 is sampled to confirm the validity of the temperature of the power system 10. If the temperature of the power system 10 is greater than or equal to the first temperature threshold A, the power system 10 enters torque-limited operation with zero torque. If the speed of the power system 10 is greater than or equal to the field-weakening control speed, the power system 10 enters the field-weakening control mode. If the temperature of the power system 10 continues to rise and is greater than or equal to the second temperature threshold (A+10), the power system 10 sends a speed-limiting request to the main controller 20 or sends a speed-limiting request and the maximum allowable speed at the same time, and can also send a fault alarm request. After the main controller 20 decelerates the vehicle speed, if the temperature of the power battery decreases by a preset difference based on the first temperature threshold, such as A-10, the power system 10 returns to normal operation.

[0137] Figure 7A schematic diagram of the communication architecture of a vehicle according to an embodiment of this application is shown.

[0138] A sixth aspect of this application provides a vehicle including a powertrain system 100 as described in any of the first aspects.

[0139] In some embodiments, the at least one power system 10 includes: a front drive motor system 13, a rear drive motor system 14, and a generator system 15; the vehicle also includes: front wheels, rear wheels, and an engine, the front wheels being connected to the permanent magnet synchronous motor 12 of the front drive motor system 13, the rear wheels being connected to the permanent magnet synchronous motor 12 of the rear drive motor system 14, and the engine being connected to the permanent magnet synchronous motor 12 of the generator system 15.

[0140] In some embodiments, the vehicle further includes: a power battery system 30, an engine system 40, a user reminder interface 50, and a following vehicle reminder window 60.

[0141] like Figure 7 As shown, the main controller 20 is connected to each power system 10, power battery system 30, and engine system 40 via the first bus (CAN1H) and the second bus (CAN2L), and is also connected to the user reminder interface 50 and the following vehicle reminder window 60 via the first bus (CAN1H) and the second bus (CAN2L). Signal transmission and interaction are performed through the CAN2H and CAN2L buses. The power battery system 30 is used for energy supply and storage for the three high-voltage power units: the front drive motor system 13, the rear drive motor system 14, and the generator system 15. During vehicle operation, the main controller 20 completes the energy distribution of the entire vehicle according to the driver's driving needs and sends torque demand commands to the front drive motor system 13 and the rear drive motor system 14. In this architecture, the front drive motor system 13 and the rear drive motor system 14 are permanent magnet synchronous motor systems 12.

[0142] Figure 8 A schematic diagram of the structure of a computer system suitable for implementing the electronic device of the present application is shown.

[0143] A seventh aspect of this application provides an electronic device, one or more processors, and one or more memories, wherein at least one piece of program code is stored in the one or more memories, and the at least one piece of program code is loaded and executed by the one or more processors to perform the operation performed by any method described in the second aspect, or to perform the operation performed by any method described in the fourth aspect.

[0144] like Figure 8As shown, the electronic device 400 is manifested in the form of a general-purpose computing device. The components of the electronic device 400 may include, but are not limited to: at least one processing unit 410, at least one storage unit 420, and a bus 430 connecting different system components (including storage unit 420 and processing unit 410).

[0145] The storage unit stores program code, which can be executed by the processing unit 410, causing the processing unit 410 to perform the steps described in the "Embodiment Method" section above according to various exemplary embodiments of this application.

[0146] Storage unit 420 may include readable media in the form of volatile storage units, such as random access memory (RAM) 421 and / or cache 422, and may further include read-only memory (ROM) 423.

[0147] Storage unit 420 may also include a program / utility 424 having a set (at least one) of program modules 425, such program modules 425 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.

[0148] Bus 430 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the various bus structures.

[0149] Electronic device 400 can also communicate with one or more external devices 500 (e.g., keyboard, pointing device, Bluetooth device, etc.), one or more devices that enable a user to interact with electronic device 400, and / or any device that enables electronic device 400 to communicate with one or more other computing devices (e.g., router, modem, etc.). This communication can be performed through I / O (input / output) interface 450, which can also be connected to display unit 440 to display the communication content. Furthermore, electronic device 400 can communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public network, such as the Internet) via network adapter 460. As shown, network adapter 460 communicates with other modules of electronic device 400 via bus 430. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 400, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0150] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored as one or more instructions or codes on or transmitted via a computer-readable medium. Other examples and embodiments are within the scope and spirit of this invention and the appended claims. For example, due to the nature of software, the functions described above can be implemented using software executed by a processor, hardware, firmware, hardwired, or any combination thereof. Furthermore, the functional units can be integrated into a single processing unit, or each unit can exist physically separately, or two or more units can be integrated into a single unit.

[0151] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between units or modules may be electrical or other forms.

[0152] The units described as separate components may or may not be physically separate. Similarly, the components of the control device may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0153] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0154] An eighth aspect of this application provides a computer-readable storage medium storing at least one computer program instruction, which is loaded and executed by a processor to perform the operation as described in any of the methods in the first aspect or any of the methods in the second aspect.

[0155] Computer-readable storage media may be portable compact disc read-only memory (CD-ROM) and include program code, and may run on a terminal device, such as a personal computer. However, the computer-readable storage medium of this application is not limited thereto. In this application, the readable storage medium may be any tangible medium that contains or stores a program that may be used by or in conjunction with an instruction execution system, apparatus, or device.

[0156] A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.

[0157] Program code for performing the operations of this application can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's device, as a standalone software package, partially on the user's computing device and partially on a process computing device, or entirely on a process computing device or server. In cases involving process computing devices, the process computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0158] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A powertrain system for a vehicle, characterized in that, include: At least one power system, each power system including a sub-controller and a permanent magnet synchronous motor, the sub-controller being configured to: after the power system enters a first state, when the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets a preset temperature rise condition, send an effective speed limit request, wherein the first state is when the temperature of the permanent magnet synchronous motor and / or the sub-controller is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor enters a torque-limited operation state and the permanent magnet synchronous motor has not stopped rotating; A main controller, communicatively connected to the sub-controllers, is configured to: upon receiving the valid speed limit request, acquire the maximum permissible speed of the permanent magnet synchronous motor in a second state, determine the target vehicle speed based on the maximum permissible speed, and control the vehicle to decelerate to the target vehicle speed. The second state is when the permanent magnet synchronous motor is in a field weakening control mode, and the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the temperature rise condition.

2. The powertrain system of the vehicle according to claim 1, characterized in that, The main controller is further configured to: receive a speed limit request carrying a signal value sent by the sub-controller, and determine whether the speed limit request is a valid speed limit request based on the signal value.

3. The powertrain system of the vehicle according to claim 1, characterized in that, When obtaining the maximum permissible speed of the permanent magnet synchronous motor in the second state, the main controller is further configured as follows: Receive the maximum permissible speed of the permanent magnet synchronous motor in the second state sent by the sub-controller; or In the second state, the back electromotive force generated by the permanent magnet synchronous motor at a reference speed is obtained, and the maximum allowable speed is determined based on the back electromotive force.

4. The powertrain system of the vehicle according to claim 1, characterized in that, The sub-controller is also configured to: In the second state, the back electromotive force generated by the permanent magnet synchronous motor at a reference speed is obtained, and the maximum allowable speed is determined based on the back electromotive force.

5. The powertrain system of the vehicle according to claim 3 or 4, characterized in that, The vehicle also includes a power battery, and the maximum permissible speed is determined based on the following method: Obtain the voltage of the power battery and determine the product between the voltage of the power battery and the reference speed of the permanent magnet synchronous motor; The maximum permissible rotational speed is determined based on the ratio between the product and the back electromotive force.

6. The powertrain system according to claim 1, characterized in that, The preset temperature rise conditions include: The permanent magnet synchronous motor and / or the sub-controller have a first temperature at a first moment that is greater than a second temperature at a second moment, the temperature difference between the first temperature and the second temperature is greater than or equal to a preset temperature difference threshold, the first moment is later than the second moment, and the second moment is the moment when the power system enters the first state; or The temperature of the permanent magnet synchronous motor and / or the sub-controller is greater than or equal to a second temperature threshold, wherein the second temperature threshold is greater than the first temperature threshold.

7. A method for overheat protection of a vehicle's powertrain system, characterized in that, The powertrain system includes a main controller and at least one power system, each power system including a sub-controller and a permanent magnet synchronous motor, the method being executed on the main controller, the method comprising: Upon receiving the effective speed limit request, the maximum permissible speed of the permanent magnet synchronous motor in the second state is obtained; wherein, the effective speed limit request is sent by the sub-controller after the power system enters the first state, when the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets a preset temperature rise condition, the first state is when the temperature of the permanent magnet synchronous motor and / or the sub-controller is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor enters a torque-limited operation state and the permanent magnet synchronous motor has not stopped rotating, and the second state is when the permanent magnet synchronous motor is in a field-weakening control mode and the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the temperature rise condition; The target vehicle speed is determined based on the maximum permissible rotational speed. Control the vehicle to decelerate to the target speed.

8. The method according to claim 7, characterized in that, The vehicle also includes a human-machine interface module and vehicle lights. When controlling the vehicle to decelerate to the target speed, the method further includes: The human-computer interaction module outputs alarm prompts; and / or Control the vehicle lights to flash as a warning.

9. A method for overheat protection of a vehicle's powertrain system, characterized in that, The powertrain system includes a main controller and at least one power system, each power system including a sub-controller and a permanent magnet synchronous motor, the method being executed on the sub-controller, the method including: After the power system enters the first state, when the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the preset temperature rise condition, a valid speed limit request is sent so that the main controller, upon receiving the valid speed limit request, obtains the maximum allowable speed of the permanent magnet synchronous motor in the second state, determines the target speed of the vehicle based on the maximum allowable speed, and controls the vehicle to decelerate to the target speed. The first state is when the temperature of the permanent magnet synchronous motor and / or the sub-controller is greater than or equal to a preset first temperature threshold, the permanent magnet synchronous motor enters a torque-limited operation and the permanent magnet synchronous motor does not stop rotating, and the second state is when the permanent magnet synchronous motor is in a field-weakening control mode and the temperature rise of the permanent magnet synchronous motor and / or the sub-controller meets the temperature rise condition.

10. The method according to claim 9, characterized in that, The method further includes: After the power system enters the first state, if the speed of the permanent magnet synchronous motor is greater than or equal to the preset field weakening control mode speed, then the permanent magnet synchronous motor is controlled to enter the field weakening control mode.

11. A vehicle, characterized in that, Includes the powertrain system of the vehicle as described in any one of claims 1-7.

12. The vehicle according to claim 11, characterized in that, The at least one power system includes: a front-drive motor system, a rear-drive motor system, and a generator system; The vehicle also includes: front wheels, rear wheels, and an engine. The front wheels are connected to the permanent magnet synchronous motor of the front drive motor system, the rear wheels are connected to the permanent magnet synchronous motor of the rear drive motor system, and the engine is connected to the permanent magnet synchronous motor of the generator system.

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