Vehicle braking control method, device and vehicle braking system

Abstract

The present application relates to the field of vehicle braking, in particular to the field of electric vehicle braking, and specifically to a vehicle braking control method, device and vehicle braking system. A braking force generation scheme for the total required braking force of the vehicle, wherein when the vehicle speed is greater than a first speed, energy recovery braking is performed; when the vehicle speed is less than the first speed and greater than a second speed, motor reverse braking and mechanical braking are performed, and the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed; when the vehicle speed is less than the second speed, mechanical braking is performed, and the braking force is generated by the mechanical braking. The combination of the three braking modes of energy recovery braking, motor reverse braking and mechanical braking is realized to ensure the braking effect, reduce the electric energy consumed at low speeds, and avoid the occurrence of problems such as overheating or failure of the mechanical braking device caused by frequent braking of the vehicle when it is driving downhill for a long time or at high speed.

Description

Technical Field

[0001] The present application relates to the field of vehicle braking, in particular to the field of electric vehicle braking, and specifically to a vehicle braking control method, device and vehicle braking system. Background Art

[0002] In daily life, for example, traffic accidents caused by truck brake failure often occur. The reasons for truck brake failure are usually the following: 1. Severe overloading; 2. Long-term braking when going downhill and frequent braking at high speeds, which causes the brake wheel hub to overheat, resulting in thermal decay of the mechanical brake device; 3. Lack of maintenance of the brake system leads to hydraulic system failure. Therefore, how to avoid traffic accidents caused by overheating of the mechanical brake device and failure of the hydraulic system has become an urgent problem to be solved in the industry. Summary of the invention

[0003] In view of the above problems in the prior art, the purpose of the embodiments of the present application is to provide a vehicle braking control method, device and vehicle braking system, which can provide different braking schemes for the vehicle according to different scenarios, thereby reducing the risk of traffic accidents caused by braking failure.

[0004] To achieve the above-mentioned purpose, the first aspect of the present application provides a vehicle braking control method, including obtaining the vehicle speed, wherein when the vehicle speed is greater than a first speed, energy recovery braking is performed, energy is recovered by generating electricity through a motor, and a battery is charged to generate braking force; when the vehicle speed is less than the first speed and greater than a second speed, motor reverse braking and mechanical braking are performed, the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed, and the electric energy generated by the motor is consumed by a power consumption device; when the vehicle speed is less than the second speed, mechanical braking is performed, and braking force is generated by mechanical braking. The power consumption device may be a resistor, an electrical appliance, etc. in a circuit, and the electrical appliance may be, for example, a cooling device.

[0005] By adopting the above scheme, energy recovery at high speed (greater than the first speed) can ensure the energy recovery effect, so that the vehicle speed can be steadily reduced; and the occurrence of mechanical brake failure caused by overheating of the brake hub due to long-term and frequent mechanical braking can be reduced.

[0006] At medium speed (less than the first speed and greater than the second speed), motor reverse braking and mechanical braking are performed. In this way, motor reverse braking and mechanical braking back up each other, avoiding or suppressing the situation where sufficient braking force cannot be provided when one of them fails.

[0007] Moreover, at medium speeds, the braking force generated by energy recovery braking is small, so it may not provide sufficient braking force. However, the present application uses motor reverse braking in combination with mechanical braking, which can prevent the situation where sufficient braking force cannot be provided compared to the method of using energy recovery braking in combination with mechanical braking.

[0008] In a possible implementation, during the execution of mechanical braking, when the temperature of the mechanical braking device exceeds a predetermined temperature, motor reverse braking is also executed, and the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed.

[0009] By adopting the above solution, when the mechanical brake device overheats, the motor is connected for reverse braking to ensure that the total braking force remains unchanged, thereby avoiding the vehicle being unable to be effectively braked due to a decrease in the braking force provided by the mechanical brake device due to overheating or even brake failure, thereby preventing a traffic accident.

[0010] In addition, at low speed (less than the second speed), the motor reverse braking is only engaged when the mechanical brake device is overheated. Compared with the situation where the reverse braking is always engaged, the motor reverse braking can be avoided as much as possible, thereby reducing energy consumption.

[0011] In a possible implementation, based on the corresponding relationship between the temperature of the mechanical brake device and the friction coefficient of the lining of the mechanical brake device, the temperature of the mechanical brake device is obtained by calculating the friction coefficient, and the friction coefficient is obtained by the following method:

[0012] The total required braking torque is obtained according to the product of vehicle speed, vehicle load and wheel radius;

[0013] The motor torque is obtained according to the motor speed, the motor voltage and the motor external characteristic curve;

[0014] Obtaining a mechanical braking torque according to a difference between the total required braking torque and the motor braking torque;

[0015] The friction coefficient of the lining of the mechanical brake device is obtained according to the mechanical braking torque and the hydraulic pressure, the lining radius of the mechanical brake device, and the lining area of ​​the mechanical brake device.

[0016] By adopting the above solution, the problem that it is difficult to obtain the temperature of the mechanical brake device through measurement due to the difficulty in installing a temperature sensor on the mechanical brake device is solved.

[0017] In a possible implementation, when reverse braking of the motor is performed, the electric energy generated by the motor is used to drive a cooling unit to perform a cooling operation on the motor.

[0018] By adopting the above solution, when the motor is reversely braked, the electric energy in the circuit can be used to drive the cooling unit, thereby realizing energy recycling and heat dissipation of the motor.

[0019] In a possible implementation, the cooling operation includes: when a braking command is received, calculating the thermal power of the motor according to the acquired current of the motor and the current of the motor; and controlling the cooling unit to perform the cooling operation according to the thermal power of the motor.

[0020] By adopting the above solution, the thermal power of the motor is used as a parameter to determine whether the motor is overheated, thereby avoiding the hysteresis problem caused by determining whether the motor is overheated only by detecting the motor temperature, and the temperature of the motor can be controlled more accurately.

[0021] In a possible implementation manner, the cooling operation further includes controlling a cooling unit to perform a cooling operation on the motor according to the acquired temperature of the motor.

[0022] By adopting the above solution, the thermal power and motor temperature of the motor are both used as parameters for judging whether the motor is overheated, thereby avoiding the hysteresis problem caused by judging whether the motor is overheated only by detecting the motor temperature, and the temperature of the motor can be controlled more accurately.

[0023] In a possible implementation, during energy recovery braking, when the total required braking force is greater than the maximum braking force that can be provided by energy recovery, mechanical braking is also performed, and the braking force generated by the mechanical braking is superimposed on the braking force generated by the energy recovery braking.

[0024] By adopting the above solution, on the one hand, the efficiency of energy recovery can be guaranteed, and on the other hand, traffic accidents caused by insufficient braking force when the vehicle is performing energy recovery can be avoided.

[0025] In a possible implementation, during mechanical braking and motor reverse braking, the braking force of the motor reverse braking is initially greater than the braking force of the mechanical braking, and the braking force of the motor reverse braking decreases as the speed decreases, while the braking force of the mechanical braking increases as the speed decreases.

[0026] In a possible implementation, when the battery power is less than a first power, energy recovery braking is performed.

[0027] By adopting the above solution, the occurrence of battery overcharging can be avoided.

[0028] In one possible implementation, the vehicle is an electric truck.

[0029] A second aspect of the present application provides a vehicle braking control device, comprising: a speed acquisition module for acquiring a vehicle speed, and a vehicle braking control module, wherein the vehicle braking control module is used to control the vehicle to perform braking according to the vehicle speed, wherein when the vehicle speed is greater than a first speed, energy recovery braking is performed, energy is recovered by generating electricity through a motor, and a battery is charged to generate braking force; when the vehicle speed is less than the first speed and greater than a second speed, a process including motor reverse braking and mechanical braking is performed, the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed, and the electric energy generated by the motor is consumed by a power consumption device; when the vehicle speed is less than the second speed, at least mechanical braking is performed, and the braking force is generated by the mechanical braking.

[0030] In a possible implementation, during mechanical braking, when the temperature of the mechanical brake device exceeds a predetermined temperature, motor reverse braking is also performed, and the braking force generated by the motor reverse braking and the braking force generated by the mechanical brake are superimposed.

[0031] In a possible implementation, when the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed, the braking force of the motor reverse braking increases as the speed decreases, and the braking force of the mechanical braking decreases as the speed decreases.

[0032] In a possible implementation, based on the corresponding relationship between the temperature of the mechanical brake device and the friction coefficient of the lining of the mechanical brake device, the temperature of the mechanical brake device is obtained by calculating the friction coefficient, and the friction coefficient is obtained by the following method:

[0033] The total required braking torque is obtained according to the product of vehicle speed, vehicle load and wheel radius;

[0034] The motor torque is obtained according to the motor speed, the motor voltage and the motor external characteristic curve;

[0035] Obtaining a mechanical braking torque according to a difference between the total required braking torque and the motor braking torque;

[0036] The friction coefficient of the lining of the mechanical brake device is obtained according to the mechanical braking torque and the hydraulic pressure, the lining radius of the mechanical brake device, and the lining area of ​​the mechanical brake device.

[0037] In a possible implementation, when reverse braking of the motor is performed, the electric energy generated by the motor is used to drive a cooling unit to perform a cooling operation on the motor.

[0038] In a possible implementation, the cooling operation includes:

[0039] When a braking command is received, the motor thermal power is calculated according to the obtained motor current and the motor current;

[0040] The cooling unit is controlled to perform a cooling operation according to the motor thermal power.

[0041] In a possible implementation manner, the cooling operation further includes controlling a cooling unit to perform a cooling operation on the motor according to the acquired temperature of the motor.

[0042] In a possible implementation, during energy recovery braking, when the total required braking force is greater than the maximum braking force that can be provided by energy recovery braking, mechanical braking is also performed, and the braking force generated by the mechanical braking is superimposed on the braking force generated by the energy recovery braking.

[0043] In a possible implementation, when executing mechanical braking and motor reverse braking, the braking force of the motor reverse braking is initially greater than the braking force of the mechanical braking, and the braking force of the motor reverse braking decreases as the speed decreases, while the braking force of the mechanical braking increases as the speed decreases.

[0044] In a possible implementation, when the battery power is less than a first power, energy recovery braking is performed.

[0045] In one possible implementation, the vehicle is an electric truck.

[0046] The advantages and effects of the vehicle braking control device provided in the second aspect of the present application are the same as the vehicle braking control method and its possible implementation methods improved in the first aspect of the present application, and will not be repeated here.

[0047] The third aspect of the present application provides a vehicle braking system, comprising: a motor, a mechanical braking device, a battery, a vehicle braking control device, a vehicle speed acquisition device and a plurality of control switches, wherein the vehicle braking control device is used to control the connection and disconnection of the control switch according to the vehicle speed acquired in real time to adjust the braking scheme, wherein when the vehicle speed is greater than a first speed, energy recovery braking is performed, the vehicle speed control switch is located at a first speed limit, the energy recovery switch is located at a first energy recovery limit, the brake switch is connected, the motor and the battery form a series circuit, the motor generates electricity to recover energy, and charges the battery to generate braking force; when the vehicle speed is less than a first speed, the energy recovery brake is performed, the vehicle speed control switch is located at a first speed limit, the energy recovery switch is located at a first energy recovery limit, the brake switch is connected, the motor and the battery form a series circuit, the motor generates electricity to recover energy, and the battery is charged ... When the first speed is greater than the second speed, the motor reverse braking and mechanical braking are executed, the vehicle speed control switch is located at the second speed limit, the energy recovery switch is located at the second energy recovery limit, the brake switch is disconnected, and the braking force supplement switch is connected, the motor and the battery form a series circuit, the mechanical brake device and the motor form a parallel circuit, the braking force generated by the motor reverse braking and the braking force generated by the mechanical brake are superimposed, and the electric energy generated by the motor is consumed by the power consumption device; when the vehicle speed is less than the second speed, the vehicle speed control switch is located at the third speed limit, the mechanical brake device and the battery form a series circuit, mechanical braking is executed, and the braking force is generated by the mechanical brake.

[0048] In a possible implementation, it also includes a mechanical brake device temperature control switch. When the temperature of the mechanical brake device exceeds a predetermined temperature, the motor reverse braking is also performed. The mechanical brake device temperature control switch is connected, and the mechanical brake device also forms a parallel circuit with the motor. The braking force generated by the motor reverse braking and the braking force generated by the mechanical brake are superimposed.

[0049] In a possible implementation, when the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed, the braking force of the motor reverse braking increases as the speed decreases, and the braking force of the mechanical braking decreases as the speed decreases.

[0050] In a possible implementation, based on the corresponding relationship between the temperature of the mechanical brake device and the friction coefficient of the lining of the mechanical brake device, the temperature of the mechanical brake device is obtained by calculating the friction coefficient, and the friction coefficient is obtained by the following method:

[0051] The total required braking torque is obtained according to the product of vehicle speed, vehicle load and wheel radius;

[0052] The braking torque of the motor is obtained according to the motor speed, the motor voltage and the motor external characteristic curve;

[0053] Obtaining a mechanical braking torque according to a difference between the total required braking torque and the motor braking torque;

[0054] The friction coefficient of the lining of the mechanical brake device is obtained according to the mechanical braking torque and the hydraulic pressure, the lining radius of the mechanical brake device, and the lining area of ​​the mechanical brake device.

[0055] In a possible implementation, a cooling device is further included. When reverse braking of the motor is performed, the motor and the cooling device form a series circuit, and the electric energy generated by the motor is used to drive a cooling unit to perform a cooling operation on the motor.

[0056] In a possible implementation, it also includes: a motor control device, which is used to obtain the current of the motor when a braking command is received, a vehicle braking control device calculates the motor thermal power based on the motor current, and the cooling control device controls the cooling unit to perform cooling operations on the motor based on the motor thermal power.

[0057] In a possible implementation, the device further includes: a temperature sensor for acquiring the temperature of the motor; and a cooling control device for controlling the cooling device to perform a cooling operation on the motor according to the temperature.

[0058] In one possible implementation, when the total required braking force is greater than the maximum braking force that can be provided by energy recovery braking, mechanical braking is also performed, the braking force supplement switch is connected, the motor also forms a parallel circuit with the mechanical braking device, and the braking force generated by the mechanical braking is superimposed on the braking force generated by the energy recovery braking.

[0059] In one possible implementation, when performing motor reverse braking and mechanical braking, the braking force of the motor reverse braking is initially greater than the braking force of the mechanical braking, and the braking force of the motor reverse braking decreases as the speed decreases, while the braking force of the mechanical braking increases as the speed decreases.

[0060] In a possible implementation, it is characterized in that when the battery power is greater than the first power, mechanical braking is performed, the battery power control switch is located at the second power limit, and the battery and the mechanical braking device form a series circuit.

[0061] In one possible implementation, the vehicle is an electric truck.

[0062] The advantages and effects of the vehicle braking system provided in the third aspect of the present application are the same as the vehicle braking control method and its possible implementation methods improved in the first aspect of the present application, and will not be repeated here.

[0063] The fourth aspect of the present application provides a computing device, comprising: a bus; a communication interface connected to the bus; at least one processor connected to the bus; and at least one memory connected to the bus and storing program instructions, wherein when the program instructions are executed by the at least one processor, the at least one processor executes any one of the methods provided in the first aspect and its possible implementation methods.

[0064] A fifth aspect of the present application provides a computer-readable storage medium having program instructions stored thereon, which, when executed by a computer, causes the computer to execute any one of the methods provided in the first aspect and its possible implementations.

[0065] The sixth aspect of the present application provides a computer program, by running the computer can execute any of the methods provided by the first aspect and its possible implementations, or function as any of the devices provided by the second aspect and its possible implementations.

[0066] These and other aspects of the present application will become more apparent from the following description of the embodiment(s). BRIEF DESCRIPTION OF THE DRAWINGS

[0067] The following further illustrates the various features of the present application and the connections between the various features with reference to the accompanying drawings. The accompanying drawings are all exemplary, and some features are not shown in actual proportion. Some drawings may omit features that are conventional in the field involved in the present application and are not necessary for the present application, or additional features that are not necessary for the present application may be shown. The combination of the various features shown in the accompanying drawings is not intended to limit the present application. In addition, throughout this specification, the same figure numerals refer to the same content. The specific description of the drawings is as follows:

[0068] Figure 1 is a schematic structural diagram of a vehicle braking system provided in an embodiment of the present application;

[0069] Figure 2 is a schematic structural diagram of a cooling system for cooling a motor provided in an embodiment of the present application;

[0070] Figure 3 is a flow chart of a vehicle braking control method provided by an embodiment of the present application;

[0071] Figure 4 is a flow chart of a vehicle braking method provided by an embodiment of the present application;

[0072] Figure 5a-5f It is a schematic diagram showing the change of the electric motor force and mechanical braking force over time when the vehicle is braking;

[0073] Figure 6a-6d It is a schematic diagram of the change of the motor force and mechanical braking force over time during the period from the vehicle braking to the vehicle stopping;

[0074] Figure 7 is a flow chart of a motor cooling control method provided by an embodiment of the present application;

[0075] Figure 8a-8g is a schematic diagram of a control circuit of a vehicle braking system provided in an embodiment of the present application;

[0076] Fig. 9 It is a structural schematic diagram of a computing device provided in some embodiments of the present application.

[0077] Description of Reference Numerals

[0078] Brake pedal control switch 1; energy recovery switch 2; speed sensor control switch 3; mechanical brake device overheat switch 4; braking force supplement switch 5; battery power control switch 6; brake switch 7; diode 8; A / D converter 9; sensor 10; speed sensor 11; hydraulic pressure sensor 12; angle sensor 13; load sensor 15; temperature sensor 16; vehicle brake control device 20; calculation module 21; brake force distribution module 22; motor control device 30; mechanical brake control device 40; motor 50; mechanical brake device 60; alarm device 70; cooling control device 80; cooling device 90; vehicle brake system 100; cooling system 110; battery 120; computing device 1500; processor 1510; memory 1520; communication interface 1530; bus 1540. DETAILED DESCRIPTION

[0079] The technical solutions involved in the specific implementation of the present application are described below in conjunction with the drawings in the implementation. Before describing the specific content of the technical solution, the terms used in the present application are briefly explained.

[0080] The words "first, second, third, etc." or module A, module B, module C and other similar terms in the specification and claims are only used to distinguish similar objects and do not represent a specific ordering of the objects. It is understandable that the specific order or sequence can be interchanged where permitted so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0081] The term "comprising" as used in the description and claims should not be interpreted as being limited to what is listed thereafter; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the features, integers, steps or components mentioned, but does not exclude the presence or addition of one or more other features, integers, steps or components and groups thereof. Therefore, the expression "a device comprising means A and B" should not be limited to a device consisting of components A and B only.

[0082] References to "one embodiment" or "an embodiment" in this specification mean that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present application. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing in various places in this specification do not necessarily refer to the same embodiment, but may refer to the same embodiment. In addition, in one or more embodiments, the particular features, structures, or characteristics can be combined in any appropriate manner, as would be apparent to one of ordinary skill in the art from this disclosure.

[0083] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present application. In case of any inconsistency, the meaning described in this specification or the meaning derived from the contents recorded in this specification shall prevail. In addition, the terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0084] Mechanical braking, also known as braking, refers to the use of mechanical devices to stop or reduce the speed of a running locomotive, vehicle, other transportation tools or machinery. Commonly used vehicle mechanical braking methods are divided into: drum brakes and disc brakes. Large trucks generally use drum brakes. Mechanical braking devices usually have a brake motor driving a hydraulic mechanism to drive the brake to generate braking force through friction with the wheel.

[0085] Braking Energy Recovery (BEDR) is commonly used in vehicles or rail transit. It refers to the operation of charging the battery when the reverse electromotive force energy generated by the rotation of the motor is higher than the voltage of the drive motor when the vehicle is coasting or braking.

[0086] Motor reverse braking refers to the operation of quickly braking the motor through the reverse torque on the motor rotor. The reverse torque of motor reverse braking is achieved by changing the direction of the rotating magnetic field (exchanging the wiring of the two-phase stator winding).

[0087] The superimposed regenerative braking system (RBS) works as follows: after the driver steps on the brake pedal, the mechanical brake device coupled to the brake pedal performs the braking operation, and at the same time, the braking force generated by the reverse connection of the motor is superimposed on the mechanical braking force to assist braking.

[0088] The Cooperative Regenerative Braking System (CRBS) works as follows: after the driver steps on the brake pedal, the sensor obtains the current brake pedal depression angle, the control device determines the driver's braking needs based on the angular velocity, and calculates the required braking force of the vehicle based on the brake pedal depression angle and vehicle speed, and then the motor reverse braking is used as the main braking source for braking operation. When the braking force generated by the motor reverse braking is insufficient, mechanical braking is used as compensation for the motor reverse braking.

[0089] The Electronic Stability Program (ESP) works by analyzing and calculating the vehicle's driving status information transmitted from various sensors, and then sending instructions to the vehicle's controllers to maintain the vehicle's dynamic balance.

[0090] Related technology 1:

[0091] At present, hydraulic retarder is used to assist vehicle braking. The hydraulic retarder includes a housing as a stator and a rotor located in the housing. Blades are arranged on both the rotor and the stator. The housing is connected to the rear end or frame of the vehicle transmission device, and the rotor is connected to the transmission shaft of the vehicle through a hollow shaft. During operation, the rotor rotates relative to the housing, and the retarding is generated by liquid damping. By means of the operation of the control valve, pressure is applied to the oil pool so that the working fluid is filled into the working chamber between the rotor and the stator. When the rotor rotates, a torque is applied to the stator through the working fluid, and the counter-torque of the stator becomes the braking torque of the rotor. The magnitude of the torque depends on the volume and pressure of the liquid in the working chamber (depending on the braking strength gear set by the control valve) and the speed of the rotor. The kinetic energy of the vehicle is converted into heat energy through the friction between the rotor and the working fluid and the impact of the rotor on the stator, thereby increasing the temperature of the working fluid. The working fluid is introduced into the heat exchange device for circulation, transferring the heat to the cooling water, and then dissipating it through the engine cooling system.

[0092] The engagement and disengagement between the rotor of the hydraulic retarder and the drive shaft of the vehicle will produce a long time lag. When the vehicle is running but the retarder is not working, the rotor will rotate with the rotating shaft, which will consume a certain amount of power. Its structure is complex and the cost is high. The cost of installing a hydraulic retarder is expensive.

[0093] Related technology 2:

[0094] The braking operation is performed using RBS or CRBS. In RBS, the brake pedal and the mechanical brake mechanism are coupled. During a braking process, as long as the brake pedal is pressed, the mechanical brake device will brake, and the motor reverse braking is only superimposed on the mechanical braking. Therefore, the motor reverse braking is not the main braking source to provide braking force.

[0095] CRBS focuses on energy recovery, and braking is an additional benefit of energy recovery. When the vehicle speed is high, the energy recovered by the motor can generate a large braking force, but when the vehicle speed is low, the braking generated by the energy recovered by the motor is small and cannot meet the braking requirements. In addition, when the mechanical brake device overheats or fails, CRSB cannot provide reliable braking guarantee.

[0096] In view of the above problems of the related art, the present application provides a vehicle braking control method, device and vehicle braking system. According to the vehicle speed and vehicle state, three braking schemes are selected: energy recovery, motor reverse braking and mechanical braking, so that energy recovery is mainly performed when the vehicle brakes at high speed, motor reverse braking and mechanical braking are performed simultaneously when the vehicle brakes at medium speed, and mechanical braking is mainly performed when the vehicle brakes at low speed. Among them, the braking system, braking method and braking device of the present application are applied to the braking of electric vehicles and hybrid vehicles, for example, in the braking of large electric trucks.

[0097] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0098] First Embodiment: Vehicle Braking System

[0099] The first embodiment of the present application relates to a vehicle braking system, which is mainly used in braking of large electric trucks.

[0100] Figure 1 1 is a schematic diagram of a vehicle brake system 100 provided in an embodiment of the present application. The vehicle brake system 100 comprises: a sensor 10, a vehicle brake control device 20, a motor control device 30, a mechanical brake control device 40, a motor 50, a mechanical brake device 60 and an alarm device 70.

[0101] In the embodiment of the present application, the motor 50 is capable of driving a DC motor for driving the vehicle.

[0102] The sensor 10 includes a speed sensor 11 for detecting vehicle speed, a hydraulic pressure sensor 12 for detecting hydraulic pressure of a mechanical brake device, an angle sensor 13 for detecting a brake pedal depression angle, and a load sensor 14 for detecting vehicle load.

[0103] The vehicle braking control device 20 can obtain the data of the sensor 10 and analyze and calculate the data. The vehicle braking control device 20 includes a vehicle braking control module, which may include a calculation module 21 and a braking allocation module 22. The calculation module 21 obtains the data of the sensor 10 and analyzes and calculates the data, so as to formulate a corresponding braking plan and braking force. The analysis of the data by the calculation module 21 includes: obtaining the vehicle speed when braking is required and formulating a braking plan according to the speed. The calculation of the data by the calculation module 21 includes: calculating the angular acceleration by the depression angle of the brake pedal obtained by the brake pedal angle sensor 13; calculating the current total required braking force of the vehicle according to the depression angle and angular acceleration; the real-time electric power of the motor; and calculating the friction coefficient of the mechanical brake device. The braking allocation module 22 is used to allocate the mechanical braking force and / or the electric braking force according to the total required braking force calculated by the calculation module 21 and in combination with the braking plan. Among them, the vehicle braking control device 20 can be implemented by software, hardware, or a combination of software and hardware, and can also be part or all of an electronic device. In some embodiments, the vehicle braking control device 20 can be an ESP electronic stability program, an ESC (Electronic Stability Control) electronic stability control device, a VSC (Vehicle Stability Control) body stability control device, a VSA (Vehicle Stability Assist) body stability assist device, a DSC (Dynamic Stability Control) dynamic stability control device, etc.

[0104] The mechanical brake control device 40 is used to control the operation of the mechanical brake device 60. The motor control device 30 is used to control the operation of the motor 50. The mechanical brake control device 40 and the motor control device 30 receive the braking force command output by the braking force distribution module, and control the motor 50 and the mechanical brake device 60 to perform corresponding braking operations according to the braking force command.

[0105] The warning device 70 is used to warn the user when the mechanical brake device 60 fails or overheats.

[0106] In addition, the vehicle brake system 100 further includes a cooling system 110 for cooling the vehicle. Figure 2 The cooling system 110 will be described.

[0107] Figure 2 1 is a schematic diagram of the structure of a cooling system 110 for cooling a motor provided in an embodiment of the present application.

[0108] The cooling system 110 may include a temperature sensor 15, a cooling control device 80, and a cooling device 90. The temperature sensor 15 is used to obtain the temperature of the motor 50; the cooling control device 80 is connected to the temperature sensor 15, and is used to control the cooling device 90 to cool the motor according to the temperature of the motor 50. The cooling control device 80 is also connected to the motor control device 30, and the motor control device 30 is used to obtain the real-time current of the motor 50. The calculation module 21 calculates the real-time thermal power of the motor 50 according to the real-time current of the motor 50. The cooling control device 80 controls the cooling device 90 to perform a cooling operation according to the real-time temperature of the motor 50 and the real-time thermal power of the motor 50. The cooling device 90 may include a cooling pump driven by electricity.

[0109] In the prior art, there is a certain hysteresis in detecting the motor temperature through the temperature sensor. In this regard, after creative work, the inventors added the operation of reading the motor current in real time to calculate the real-time thermal power of the motor to the traditional temperature adjustment scheme, and provided the real-time thermal power of the motor as an input to the cooling control device. Compared with the prior art, the present application can judge whether the motor is overheated according to the real-time thermal power of the motor, improve the efficiency of the cooling device, and achieve more accurate motor temperature control.

[0110] Combine the following Figure 3 , Figure 4 as well as Figure 7 The working modes of the various components of the vehicle braking system 100 provided in the embodiment of the present application are introduced.

[0111] Figure 3 The working process of the vehicle braking control system provided by the embodiment of the present application is shown.

[0112] When the driver steps on the brake pedal, the brake pedal angle sensor 13 obtains the brake pedal's depression angle, and the speed sensor 11 obtains the vehicle speed.

[0113] The vehicle brake control device 20 performs the following processing according to the acquired vehicle speed and the pedaling angle:

[0114] The braking scheme is determined according to the acquired vehicle speed, the angular acceleration is calculated according to the depression angle of the brake pedal, and the current total required braking force of the vehicle is calculated according to the angular acceleration and angle. The mechanical braking force and the electric braking force are allocated according to the braking scheme and the total required braking force, and the generated mechanical braking force command and the electric braking force command are input into the mechanical brake control device and the motor reverse braking control device.

[0115] The mechanical brake control device 40 and the motor reverse brake control device 50 control the mechanical brake device 60 and the motor 50 to perform braking according to the received mechanical braking force command and the motor braking force command, thereby reducing the vehicle speed.

[0116] During the braking process, as the braking operation proceeds, the vehicle speed will continue to change (generally gradually decrease). Therefore, the vehicle brake control device 20 will continuously adjust the braking scheme and the mechanical braking force and the electric braking force according to the vehicle speed. Figure 3 As shown, the speed sensor 11 continuously obtains the current vehicle speed and feeds back the current vehicle speed to the vehicle brake control device 20. The vehicle brake control device 20 calculates the current vehicle acceleration according to the current vehicle speed, and adjusts the distribution of the braking force in combination with the angle of the brake pedal and the angular acceleration, thereby realizing dynamic adjustment of the braking force.

[0117] The hydraulic pressure sensor 12 will continuously obtain the hydraulic pressure in the current mechanical brake device, and feed back the current hydraulic pressure of the mechanical brake device to the vehicle brake control device 20. Among them, the braking force generated by the mechanical brake device 60 is proportional to the hydraulic pressure in the current mechanical brake device (the parameter is K). After calculation, the vehicle brake control device 20 will update the generated mechanical braking force command again and then input it to the mechanical brake control device, thereby realizing dynamic adjustment of the mechanical braking force. The speed sensor 11 and the hydraulic pressure sensor 12 provide real-time feedback on the vehicle's speed and hydraulic pressure, realizing closed-loop control of the vehicle's braking system, so that the vehicle can execute different braking schemes according to the vehicle speed, thereby improving the reliability of braking.

[0118] Figure 4 The control flow of the vehicle braking control device provided in the embodiment of the present application controlling the vehicle to execute a braking scheme according to the vehicle speed is shown.

[0119] In the embodiments of the present application, "energy recovery and mechanical braking" means that the vehicle simultaneously performs energy recovery braking and mechanical braking; "motor reverse braking superimposed on mechanical braking" means that the vehicle simultaneously performs motor reverse braking and mechanical braking.

[0120] When the vehicle driver steps on the brake pedal, vehicle braking starts, and the vehicle brake control device executes step S20 to read the vehicle speed collected by the speed sensor.

[0121] Step S31: Determine whether the vehicle speed is greater than the first speed v1.

[0122] If the vehicle speed is greater than the first speed v1, step S41 is executed: determining whether the battery power is less than the first power.

[0123] If the battery power is greater than the first power, it is considered that the battery power is sufficient and energy recovery braking cannot be performed. At this time, step S81 is executed: the vehicle braking control device controls the vehicle to perform mechanical braking.

[0124] If the battery power is less than the first power, step S50 is executed: determining whether the total required braking force of the vehicle is less than the maximum braking force that can be provided by the motor.

[0125] If the total required braking force of the vehicle is less than the maximum braking force that the motor can provide, step S60 is executed: the vehicle braking control device controls the vehicle to perform energy recovery braking, recovers energy through the motor to generate electricity, and charges the battery.

[0126] If the total required braking force of the vehicle is greater than the maximum braking force that the motor can provide, step S61 is executed: the vehicle braking control device controls the vehicle to perform energy recovery braking and mechanical braking, and the braking force generated by the mechanical braking is superimposed on the braking force generated by the energy recovery braking.

[0127] If the vehicle speed is less than the first speed v1, step S32 is executed: determining whether the vehicle speed is greater than the second speed v2.

[0128] If the vehicle speed is greater than the second speed v2, step S71 is executed: the vehicle control device controls the vehicle to perform motor reverse braking and mechanical braking. In the case of motor reverse braking, step S72 is executed: the electric energy generated by motor reverse braking is used to drive the cooling device to cool the motor.

[0129] If the vehicle speed is less than the second speed v2, step S83 is executed: the vehicle brake control device controls the vehicle to perform mechanical braking. After step S83 is executed, step S90 is also executed: determining whether the mechanical brake device is overheated.

[0130] If the mechanical brake device is not overheated, then continue to execute step S83, and the vehicle performs mechanical braking until the vehicle stops. If the mechanical brake device is overheated, then execute step S84: the vehicle control device controls the vehicle to perform mechanical braking and motor reverse braking. In the case of motor reverse braking, execute step S85: the electric energy generated by motor reverse braking is used to drive the cooling device to cool the motor, and the vehicle performs motor braking and mechanical braking until the vehicle stops.

[0131] Since the structure of the mechanical brake device is relatively compact, it is difficult to install a temperature sensor on the mechanical brake device. Therefore, the temperature of the mechanical brake device is difficult to be directly obtained by measuring with a mechanical temperature sensor. Based on the corresponding relationship between the temperature of the mechanical brake device and the friction coefficient of the lining of the mechanical brake device, the calculation module of the vehicle brake control device obtains the temperature of the mechanical brake device by calculating the friction coefficient. The friction coefficient is obtained by the following method:

[0132] The vehicle speed is acquired through the speed sensor 11 , the vehicle load is acquired through the load sensor 14 , and the current mechanical brake hydraulic pressure strength is acquired through the hydraulic pressure strength sensor 12 .

[0133] The vehicle brake control device 20 calculates the actual braking torque T according to the following formula:

[0134] T=(m1+m2)·(d v / d t )·R Formula (1)

[0135] Among them, T is the actual braking torque, m1 is the vehicle load, m2 is the vehicle weight, dv / dt is the vehicle acceleration, and R is the wheel radius.

[0136] The actual braking torque includes mechanical braking torque T1 and motor braking torque T2. The motor braking torque T2 is calculated by the motor speed, motor voltage and motor external characteristic curve. The mechanical braking torque T1 can be calculated by the difference between the actual braking torque T and the motor braking torque T2.

[0137] The friction coefficient of the lining of the current mechanical brake device is calculated according to the mechanical braking torque T1 by the following formula:

[0138]

[0139] Wherein, u is the friction coefficient of the lining of the mechanical brake device, P is the hydraulic pressure, r is the radius of the lining of the mechanical brake device, and S is the area of ​​the lining of the mechanical brake device. When the friction coefficient exceeds the first threshold, it can be determined that the temperature of the mechanical brake device exceeds the predetermined temperature and the mechanical brake device is overheated. When the friction coefficient of the lining of the mechanical brake device is less than 0.2-0.3, it can be determined that the temperature of the mechanical brake device exceeds the predetermined temperature and the mechanical brake device is overheated.

[0140] Figure 7 The working process of the cooling system provided by the embodiment of the present application is shown.

[0141] When the driver steps on the brake pedal, the motor control device 30 reads the real-time current of the motor 50 , and the calculation module of the vehicle brake control device calculates the real-time thermal power of the motor according to the real-time current of the motor 50 .

[0142] The motor temperature sensor 15 acquires the motor temperature.

[0143] The cooling control device obtains the real-time thermal power and motor temperature of the motor 50, and determines whether the motor is overheated according to the thermal power and / or temperature of the motor 50. When the motor temperature exceeds the target temperature, or the motor thermal power exceeds the target thermal power, the cooling control device controls the cooling device 90 to cool the motor.

[0144] In the prior art, the temperature of the motor is usually detected by the motor temperature sensor 15, and then the temperature of the motor is fed back to the cooling control device to control the cooling of the motor. However, this process has a certain lag. The real-time current of the motor 50 is obtained by the motor control device 30, and the real-time thermal power of the motor is calculated according to the real-time current by the calculation module, so that the thermal state of the motor can be fed back to the cooling control device 80 more quickly, and then the cooling device is controlled for cooling. In this way, the cooling efficiency of the motor is improved, and the temperature of the motor is controlled more accurately.

[0145] Second Embodiment: Vehicle Braking Control Method

[0146] The second embodiment of the present application relates to a vehicle braking control method. The method realizes vehicle braking by controlling various components of the vehicle braking system of the first embodiment of the present application. The execution subject of the vehicle braking control method is the vehicle braking system provided by the first embodiment of the present application.

[0147] The braking control method of the embodiment of the present application is described below in conjunction with the accompanying drawings. The vehicle braking method of the present embodiment is performed by the vehicle braking system provided in the first embodiment of the present application.

[0148] Figure 4 It is a schematic flow chart of the vehicle braking control method provided in an embodiment of the present application.

[0149] When the vehicle driver steps on the brake pedal, the brake pedal angle sensor obtains the brake pedal's stepping angle, and the speed sensor obtains the vehicle speed. The vehicle starts braking, and the vehicle brake control device executes step S20 to read the vehicle speed.

[0150] Execute step S31: determine whether the vehicle speed is greater than the first speed v1.

[0151] When the vehicle speed is greater than the first speed v1, step S41 is executed: whether the battery power is less than the first power.

[0152] When the battery power is less than the first power, step S50 is executed to determine whether the total required braking force of the vehicle is less than the maximum braking force that the motor can provide. If so, step S60 is executed: the vehicle braking control device controls the vehicle to perform energy recovery braking.

[0153] Figure 5a A schematic diagram showing the variation of the electric brake force over time when the vehicle performs energy recovery braking, wherein the mechanical brake device does not participate in braking, the electric brake force is the total required braking force of the vehicle calculated by the vehicle brake control device, and the electric brake force remains constant over time.

[0154] If the total required braking force of the vehicle is greater than the maximum braking force that the motor can provide, step S61 is executed: the vehicle control device controls the vehicle to perform energy recovery and mechanical braking simultaneously.

[0155] Figure 5b A coordinate diagram showing the changes of the electric braking force and the mechanical braking force over time when the vehicle performs energy recovery braking and mechanical braking at the same time, wherein the electric braking force is greater than the mechanical braking force, and the mechanical braking force is the difference between the braking force required by the vehicle calculated by the vehicle braking control device and the maximum braking force that the motor can provide, and the electric braking force and the mechanical braking force remain constant over time.

[0156] When the battery power is greater than the first power, step S81 is executed: the vehicle brake control device controls the vehicle to perform mechanical braking.

[0157] The total required braking force of the vehicle can be calculated as T by the angle of the brake pedal. The angular acceleration of the brake pedal can be used to determine whether it is an emergency brake. When the angular acceleration is greater than 10 rad / s 2 When the vehicle is in an emergency braking state, the total required braking force may be 1.3 T. The first speed may be 20 to 40 km / h.

[0158] When the vehicle speed is less than the first speed v1, step S32 is executed: determining whether the vehicle speed is greater than the second speed v2.

[0159] If the vehicle speed is greater than the second speed v2, step S71 is executed: the vehicle braking control device controls the vehicle to simultaneously perform motor reverse braking and mechanical braking, and, when performing motor reverse braking, step S72 is executed: the electric energy generated by motor reverse braking is used to drive the vehicle for cooling.

[0160] Figure 5c and 5dThe coordinate diagram of the change of the motor braking force and the mechanical braking force over time when the vehicle performs motor reverse braking and mechanical braking at the same time is shown. When the total required braking force is less than the maximum braking force that the motor can provide ( Figure 5c ), mechanical braking and motor reverse braking are performed simultaneously, and the vehicle brake control device adjusts the mechanical braking force and the electric brake force according to the vehicle speed. The electric brake force is greater than the mechanical braking force at the beginning. As time changes, the vehicle speed gradually decreases, the electric brake force gradually decreases until it exits, and the mechanical braking force gradually increases. When the total required braking force is greater than the maximum braking force that the motor can provide ( Figure 5d ), and the motor reverse braking and mechanical braking are performed simultaneously. The electric braking force is greater than the mechanical braking force at the beginning. As time changes, the vehicle speed gradually decreases, the electric braking force gradually decreases until it exits, and the mechanical braking force gradually increases.

[0161] The second speed may be 10 to 15 km / h. When the motor reverse braking is performed, the electric energy generated by the motor can be used to drive the vehicle for cooling, thereby achieving energy recycling and heat dissipation of the motor.

[0162] If the vehicle speed is less than the second speed v2, step S83 is executed: the vehicle brake control device only controls the vehicle to perform mechanical braking.

[0163] Figure 5e A coordinate diagram showing the change of mechanical braking force over time when the vehicle performs mechanical braking is shown, wherein the mechanical braking force is constant.

[0164] After executing step S83, step S90 is further executed: determining whether the mechanical brake device is overheated.

[0165] When the mechanical brake device is overheated, step S84 is executed: the vehicle brake control device controls the vehicle to perform motor reverse braking on the basis of mechanical braking. Also, when performing motor reverse braking, step S85 is executed: the electric energy generated by motor reverse braking is used to drive the vehicle for cooling.

[0166] Figure 5f The coordinate diagram shows the change of the motor braking force and the mechanical braking force over time when the vehicle performs motor reverse braking and mechanical braking at the same time, the mechanical braking device is overheated and the motor reverse braking is available. At this time, the motor braking force gradually increases and the mechanical braking gradually decreases.

[0167] The above are the braking schemes used for braking vehicles at different speeds. As the vehicle speed decreases, the braking scheme may change. At the same time, in each braking scheme, the proportion of the required mechanical braking force and the electric braking force to the total required braking force may also change accordingly.

[0168] Refer to the following Figure 6a-6d , the changes in braking scheme, mechanical braking force and electric braking force during the process of braking the vehicle from a speed greater than the first speed to a stop of the vehicle are explained in combination with different scenarios.

[0169] Scenario 1: The total required braking force of the vehicle is less than the maximum braking force that the motor can provide, and the mechanical brake device operates normally. Figure 6c The figure shows the change of mechanical braking force and electric braking force over time when the vehicle is braked at a speed greater than the first speed until the vehicle stops completely. The vehicle performs energy recovery braking, mechanical braking plus motor reverse braking and mechanical braking successively from the time the brake pedal is pressed to the time the vehicle stops completely (i.e., during the period of t0-t3). At time t0, the vehicle performs energy recovery braking. As energy recovery proceeds, the vehicle speed decreases continuously until, at time t1, the vehicle speed decreases from greater than the first speed to less than the first speed and greater than the second speed. At this time, the vehicle brake control device controls the vehicle to perform mechanical braking and motor reverse braking, and adjusts the mechanical braking force and electric braking force according to the hydraulic pressure sensor to obtain the hydraulic pressure of the mechanical brake device and the vehicle deceleration calculated according to the vehicle speed. That is, as the vehicle speed decreases, the mechanical braking force gradually increases, and the electric braking force gradually decreases. As the mechanical braking plus motor reverse braking proceeds, the vehicle speed decreases continuously until, at time t2, the vehicle speed is less than the second speed. At this time, the vehicle brake control device controls the vehicle to perform mechanical braking until the vehicle stops (time t3).

[0170] Scenario 2: The total braking force required by the vehicle is less than the maximum braking force that the motor can provide, and the mechanical brake device overheats

[0171] In the following description, for the same processing in Scenario 2 as in Scenario 1, the content of Scenario 1 is cited for description, or only a brief description is given.

[0172] like Figure 6a As shown in the figure, during the period when the vehicle speed decreases from greater than the first speed to the second speed (i.e., the period from t0 to t2), the vehicle adopts the same braking scheme as in scenario 1, i.e., firstly, energy recovery braking is performed and then mechanical braking plus motor reverse braking is performed. After time t2, the vehicle speed is less than the second speed. Due to overheating of the mechanical brake device, the vehicle performs mechanical braking and motor reverse braking after time t2, and the mechanical braking force gradually decreases with time, while the motor braking force gradually increases with time, until the vehicle stops at time t3.

[0173] Scenario 3: The vehicle's total required braking force is greater than the maximum braking force that the motor can provide, and the mechanical brake device operates normally.

[0174] In the following description, for the same processing in Scenario 3 as in Scenario 1, the content of Scenario 1 is cited for description, or only a brief description is given.

[0175] Figure 6d The figure shows the change of mechanical braking force and motor braking force over time when the vehicle is braking at a speed greater than the first speed until the vehicle stops completely. The vehicle successively performs energy recovery plus mechanical braking, mechanical braking plus motor reverse braking, and mechanical braking until the vehicle stops. At time t0, the vehicle speed is greater than the first speed, the total required braking force of the vehicle is greater than the maximum braking force that the motor can provide, the vehicle performs energy recovery plus mechanical braking, and the mechanical braking force is the difference between the required braking force of the vehicle and the maximum braking force that the motor can provide. At time t1, the vehicle speed is less than the first speed and greater than the second speed, and the vehicle performs mechanical braking plus motor reverse braking. At time t2, the vehicle speed is less than the second speed, and the vehicle performs mechanical braking until the vehicle stops.

[0176] Scenario 4: The total braking force required by the vehicle is greater than the maximum braking force that the motor can provide, and the mechanical brake device is overheated

[0177] The difference between scenario 4 and scenario 3 is that the vehicle's mechanical brake device overheats. Figure 6b As shown, during the period when the vehicle speed decreases from greater than the first speed to the second speed (i.e., the period from t0 to t2), the vehicle adopts the same braking scheme as in scenario 3, i.e., first performing energy recovery plus mechanical braking and then performing mechanical braking plus motor reverse braking. After time t2, the vehicle speed is less than the second speed. Due to the overheating of the mechanical brake device, the vehicle performs mechanical braking and motor reverse braking, and the mechanical braking force gradually decreases, while the motor braking force gradually increases, until the vehicle stops at time t4.

[0178] By performing energy recovery braking at high speeds, the energy recovery efficiency can be increased; at medium speeds (less than the first speed and greater than the second speed), the motor is reversed and mechanical braking is superimposed to ensure the braking effect; and at low speeds (less than the second speed), mechanical braking is used to reduce the electric energy consumed by braking, while avoiding the occurrence of overheating or failure of the mechanical brake device caused by frequent braking when the vehicle is driving downhill for a long time or at high speed.

[0179] By using the friction coefficient of the lining of the mechanical brake device to determine whether the mechanical brake device is overheated, the problem that the mechanical brake temperature cannot be measured because the mechanical brake device cannot be equipped with a temperature sensor is solved.

[0180] Third Embodiment: Vehicle Braking System

[0181] The third embodiment of the present application provides a vehicle braking system, which implements the vehicle braking method provided in the second embodiment of the present application by controlling the connection and disconnection of various control switches in the control system, so that the vehicle adopts different braking schemes according to the speed.

[0182] Figure 8a-8g : is a circuit diagram of the vehicle braking system of the present application. Figure 8a-8g As shown, the vehicle braking system provided by the embodiment of the present application includes: a motor 60, a mechanical brake device 60, a cooling device 90, a battery 120, and a plurality of control switches. The control switches include a brake pedal control switch 1, an energy recovery switch 2, a speed sensor control switch 3, a mechanical brake device overheat switch 4, a braking force supplement switch 5, a battery power control switch 6, a brake switch 7, and a diode 8.

[0183] Among them, the brake pedal control switch 1 can control the vehicle to switch between normal driving state and braking state. When the vehicle is in normal driving state, the brake pedal control switch 1 is located at the driving limit (right limit). When the driver steps on the brake pedal to brake, the brake pedal control switch 1 is located at the braking limit (left limit).

[0184] The speed sensor control switch 3 can change the connectivity state according to the vehicle speed. When the vehicle speed is greater than the first speed, the speed sensor switch is located at the first speed limit (upper limit); when the vehicle speed is less than the first speed and greater than the second speed, the speed sensor control switch is located at the second speed limit (middle limit); when the vehicle speed is less than the second speed, the speed sensor control switch is located at the third speed limit (lower limit).

[0185] The battery power control switch 6 can change the connectivity state according to the power level of the vehicle battery. When the battery power is greater than the first power level, the battery power control switch 6 is located at the first power limit (right limit); when the battery power is less than the first power level, the battery power control switch 6 is located at the second power limit (left limit).

[0186] The mechanical brake device overheat switch 4 can change the connection state according to the temperature of the mechanical brake device or the friction coefficient of the lining of the mechanical brake device. According to the corresponding relationship between the friction coefficient of the lining of the mechanical brake device and the temperature of the mechanical brake device, when the friction coefficient of the lining of the mechanical brake device exceeds the first threshold value, it can be judged that the temperature of the mechanical brake device exceeds the predetermined temperature or that the mechanical brake device overheat switch 4 is in the connection state.

[0187] The braking force supplement switch 5 is used for connection when the electric braking force or the mechanical braking force is insufficient.

[0188] The energy recovery switch 2 is used to control whether the motor 50 performs energy recovery. When the motor 50 performs energy recovery, the energy recovery switch 2 is located at the lower limit position.

[0189] The brake switch 7 is used to control whether the vehicle performs mechanical braking or motor reverse braking. When the mechanical braking or motor reverse braking is performed, the brake switch is disconnected.

[0190] The connection and disconnection of the control switch of the brake system are explained below in conjunction with the working mode of the vehicle.

[0191] In the following, “not involved” means that the switch can be located at any limit position or can be connected or disconnected without affecting the connectivity of the circuit.

[0192] 1. The vehicle is driving without braking

[0193] Figure 8a It is the connected state of the circuit when the vehicle is in the unbraked state. Among them, the brake pedal control switch 1 is in the driving limit (right limit), the speed sensor control switch 3 is not involved, the mechanical brake device overheat switch 4 is not involved, the braking force supplement switch 5 is disconnected, the battery power control switch 6 is in the left limit (first power limit), the energy recovery switch 2 is not involved, and the brake switch 7 is connected. At this time, the motor 50 and the vehicle battery 120 form a series circuit, and the cooling device 90 and the motor 50 form a parallel circuit. At this time, the battery 120 supplies power to the motor 50 and the cooling device 90 respectively, and the motor 50 runs under the drive of the battery 120.

[0194] 2. Energy Recovery

[0195] Figure 8b It is the connected state of the circuit when the vehicle is in the energy recovery state. Among them, the brake pedal control switch 1 is located at the brake limit (left limit), the speed sensor control switch 3 is located at the upper limit (first speed limit), the mechanical brake device overheat switch 4 is not involved, the braking force supplement switch 5 is disconnected, the battery power control switch 6 is located at the left limit (first power limit), the energy recovery switch 2 is located at the lower limit, and the brake switch 7 is connected. At this time, the motor 50 and the vehicle battery 120 form a series circuit, and the cooling device 90 and the motor 50 form a parallel circuit. At this time, the battery 120 stops supplying power to the motor 50, and the motor rotor is driven to rotate under the inertia of the vehicle, so that the motor continues to run and the generated electrical energy is provided to the battery 120.

[0196] 3. Energy recovery plus mechanical braking

[0197] Figure 8cIt is the connection state of the circuit when the vehicle performs energy recovery and mechanical braking. Among them, the brake pedal control switch 1 is located at the left limit (brake limit), the speed sensor control switch 3 is located at the upper limit (first speed limit), the mechanical brake device overheat switch 4 is not involved, the braking force supplement switch 5 is connected, the battery power control switch 6 is located at the left limit (first power limit), the energy recovery switch 2 is located at the lower limit, and the brake switch 7 is connected. At this time, the motor 50 and the vehicle battery 120 form a series circuit, the cooling device 90 and the motor 50 form a parallel circuit, and the mechanical brake device 60 and the motor 50 form a parallel circuit. At this time, the motor continues to run under the inertia of the vehicle and generates electrical energy to charge the battery, and the mechanical brake device 60 performs mechanical braking.

[0198] 4. Motor reverse braking plus mechanical braking

[0199] Figure 8d It is the connectivity state of the circuit when the vehicle is executing the braking scheme of motor reverse connection and superimposed mechanical braking. Among them, the brake pedal control switch 1 is located at the left limit (brake limit), the speed sensor control switch 3 is located at the middle limit (second speed limit), the mechanical brake device overheat switch 4 is not involved, the braking force supplement switch 5 is connected, the battery power control switch 6 is located at the left limit (first power limit), the energy recovery switch 2 is located at the upper limit, and the brake switch 7 is disconnected. At this time, the motor 50 forms a series circuit with the vehicle battery 120 and the cooling device 90; the mechanical brake device 60 is connected in parallel with the motor 50 and the cooling device 90. At this time, the vehicle battery 120 drives the motor 50 for reverse braking, the mechanical brake device 60 performs mechanical braking, and the electric energy generated by the motor reverse braking is used to drive the refrigeration device 90 for cooling.

[0200] Figure 8f It is the connection state of the circuit when the vehicle is executing the braking scheme of motor reverse connection superimposed on mechanical braking. Figure 8d The difference is that at this time, the mechanical brake device 60 is overheated and the speed of the vehicle is less than the second speed. Among them, the brake pedal control switch 1 is located at the left limit (brake limit), the speed sensor control switch 3 is located at the lower limit (third speed limit), the mechanical brake device overheat switch 4 is connected, the braking force supplement switch 5 is connected, the battery power control switch 6 is located at the left limit (first power limit), the energy recovery switch 2 is located at the upper limit, and the brake switch 7 is disconnected. At this time, the motor 50 forms a series circuit with the vehicle battery 120 and the cooling device 90; the mechanical brake device 60 forms a parallel circuit with the motor 50 and the cooling device 90. At this time, the battery 120 drives the motor 50 to reverse brake, the mechanical brake device 60 performs mechanical braking, and the electric energy generated by the motor reverse braking is used to drive the refrigeration device 90 for cooling.

[0201] 5. Mechanical brake

[0202] Figure 8e It is the connectivity state of the circuit when the vehicle performs mechanical braking. Among them, the brake pedal control switch 1 is located at the left limit (brake limit), the speed sensor control switch 3 is located at the lower limit (third speed limit), the mechanical brake device overheat switch 4 is disconnected, the braking force supplement switch is not involved, the battery power control switch 6 is located at the left limit (first power limit), and the energy recovery switch 2 and the brake switch 7 are not involved. At this time, the motor 50 and the cooling device 90 are disconnected from the vehicle battery 120, and only the mechanical brake device 60 is connected in series with the vehicle battery 120. At this time, the mechanical brake device 60 performs mechanical braking.

[0203] Figure 8g It is the connected state of the circuit when the vehicle is in the mechanical braking state. Figure 8e The difference is that at this time, the battery power is greater than the first power, and no matter what the vehicle speed is, the battery does not need to be charged. Among them, the brake pedal control switch 1 is located at the left limit (brake limit), the speed sensor control switch 3 can be located at any speed limit (located at the first speed limit in the figure), the braking force supplement switch 5 is connected, the mechanical brake device overheat switch 4 is disconnected, the battery power control switch 6 is located at the right limit (second power limit), and the energy recovery switch 2 and the brake switch 7 are disconnected. At this time, the vehicle battery 120 is disconnected from the motor 50 and the cooling device 90, and the mechanical brake device 60 performs mechanical braking.

[0204] Fourth embodiment: computing device

[0205] Fig. 9 15 is a schematic structural diagram of a computing device 1500 provided in an embodiment of the present application. The computing device 1500 includes: a processor 1510 , a memory 1520 , a communication interface 1530 , and a bus 1540 .

[0206] It should be understood that Fig. 9 The communication interface 1530 in the computing device 1500 shown may be used to communicate with other devices.

[0207] The processor 1510 may be connected to a memory 1520. The memory 1520 may be used to store the program code and data. Therefore, the memory 1520 may be a storage unit inside the processor 1510, or an external storage unit independent of the processor 1510, or a component including a storage unit inside the processor 1510 and an external storage unit independent of the processor 1510.

[0208] Optionally, the computing device 1500 may further include a bus 1540. The memory 1520 and the communication interface 1530 may be connected to the processor 1510 via the bus 1540. The bus 1540 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus 1540 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig. 9 The fact that only one line is used in the diagram does not mean that there is only one bus or only one type of bus.

[0209] It should be understood that in the embodiment of the present application, the processor 1510 can adopt a central processing unit (CPU). The processor can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. Or the processor 1510 uses one or more integrated circuits to execute related programs to implement the technical solutions provided in the embodiments of the present application.

[0210] The memory 1520 may include a read-only memory and a random access memory, and provides instructions and data to the processor 1510. A portion of the processor 1510 may also include a nonvolatile random access memory. For example, the processor 1510 may also store information on the device type.

[0211] When the computing device 1500 is running, the processor 1510 executes the computer-executable instructions in the memory 1520 to perform the operating steps of the above-mentioned braking method.

[0212] It should be understood that the computing device 1500 according to the embodiment of the present application can correspond to the corresponding subjects in the methods according to the embodiments of the present application, and the above-mentioned and other operations and / or functions of each module in the computing device 1500 are respectively for implementing the corresponding processes of each method of the present embodiment, which will not be repeated here for the sake of brevity.

[0213] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0214] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0215] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0216] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0217] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0218] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0219] Fifth embodiment: computer readable storage medium

[0220] An embodiment of the present application also provides a computer-readable storage medium on which a computer program is stored. The program is executed by a processing device to perform a braking method and calculation. The method includes at least one of the solutions described in the above embodiments.

[0221] The computer storage medium of the embodiment of the present application can adopt any combination of one or more computer-readable media. Computer-readable media can be computer-readable signal media or computer-readable storage media. Computer-readable storage media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or devices, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: electrical connections with one or more wires, portable computer disks, hard disks, random access storage devices (RAM), read-only storage devices (ROM), erasable programmable read-only storage devices (EPROM or flash memory), optical fibers, portable compact disk read-only storage devices (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In this document, computer-readable storage media can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it.

[0222] A computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device component.

[0223] The program code embodied on the computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0224] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or service device. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect through the Internet).

[0225] Sixth embodiment: Computer program

[0226] The sixth embodiment of the present application provides a computer program, and a computer can execute the braking method provided in the embodiment of the present application or function as the above-mentioned braking control device by running the program.

[0227] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0228] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0229] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0230] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0231] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0232] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a service device, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory device (ROM), a random access memory device (RAM), a magnetic disk or an optical disk.

[0233] Note that the above are only preferred embodiments of the present application and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present application is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may also include more other equivalent embodiments without departing from the concept of the present invention, all of which belong to the protection scope of the present invention.

Claims

1. A vehicle braking control method, characterized in that: include: Get vehicle speed; When the vehicle speed is greater than the first speed, energy recovery braking is performed to recover energy through the motor and charge the battery; When the vehicle speed is less than the first speed and greater than the second speed, the motor reverse braking and the mechanical braking are performed, the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed, and the electric energy generated by the motor is consumed by the power consumption device; When the vehicle speed is lower than the second speed, the mechanical brake is executed to generate a braking force.

2. The method according to claim 1, characterized in that When mechanical braking is performed, when the temperature of the mechanical braking device exceeds a predetermined temperature, motor reverse braking is also performed, and the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed.

3. The method according to claim 2, characterized in that When the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed, the braking force of the motor reverse braking increases as the speed decreases, and the braking force of the mechanical braking decreases as the speed decreases.

4. The method according to claim 2 or 3, characterized in that: Based on the corresponding relationship between the temperature of the mechanical brake device and the friction coefficient of the lining of the mechanical brake device, the temperature of the mechanical brake device is obtained by calculating the friction coefficient, and the friction coefficient is obtained by the following method: The total required braking torque is obtained according to the product of vehicle speed, vehicle load and wheel radius; The motor torque is obtained according to the motor speed, the motor voltage and the motor external characteristic curve; Obtaining a mechanical braking torque according to a difference between the total required braking torque and the motor braking torque; The friction coefficient of the lining of the mechanical brake device is obtained according to the mechanical braking torque and the hydraulic pressure, the lining radius of the mechanical brake device, and the lining area of ​​the mechanical brake device.

5. The method according to claim 1, characterized in that When the motor reverse braking is performed, the electric energy generated by the motor is used to drive the cooling unit to perform a cooling operation on the motor.

6. The method according to claim 5, characterized in that The cooling operation includes: When a braking command is received, the motor thermal power is calculated according to the obtained current of the motor; The cooling unit is controlled to perform a cooling operation according to the motor thermal power.

7. The method according to claim 6, characterized in that The cooling operation further includes controlling a cooling unit to perform a cooling operation on the motor according to the acquired temperature of the motor.

8. The method according to claim 1, characterized in that When energy recovery braking is performed, when the total required braking force is greater than the maximum braking force that can be provided by energy recovery braking, mechanical braking is also performed, and the braking force generated by the mechanical braking is superimposed on the braking force generated by the energy recovery braking.

9. The method according to claim 1, characterized in that: When performing motor reverse braking and mechanical braking, initially the braking force of the motor reverse braking is greater than the braking force of the mechanical braking, and the braking force of the motor reverse braking decreases as the speed decreases, while the braking force of the mechanical braking increases as the speed decreases.

10. The method according to claim 1, characterized in that When the power level of the battery is less than a first power level, the energy recovery braking is performed.

11. The method according to claim 1, characterized in that: The vehicle is an electric truck.

12. A vehicle brake control device, characterized in that: include: The vehicle speed acquisition module is used to obtain the vehicle speed. The vehicle braking control module is used to control the vehicle to brake according to the vehicle speed, wherein: When the vehicle speed is greater than the first speed, energy recovery braking is performed to recover energy through the motor and charge the battery; When the vehicle speed is less than the first speed and greater than the second speed, the motor reverse braking and the mechanical braking are performed, the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed, and the electric energy generated by the motor is consumed by the power consumption device; When the vehicle speed is lower than the second speed, the mechanical brake is executed to generate a braking force.

13. The vehicle brake control device according to claim 12, characterized in that: When mechanical braking is performed, when the temperature of the mechanical braking device exceeds a predetermined temperature, motor reverse braking is also performed, and the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed.

14. The vehicle brake control device according to claim 13, characterized in that: When the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed, the braking force of the motor reverse braking increases as the speed decreases, and the braking force of the mechanical braking decreases as the speed decreases.

15. The vehicle brake control device according to claim 13 or 14, characterized in that: Based on the corresponding relationship between the temperature of the mechanical brake device and the friction coefficient of the lining of the mechanical brake device, the temperature of the mechanical brake device is obtained by calculating the friction coefficient, and the friction coefficient is obtained by the following method: The total required braking torque is obtained according to the product of vehicle speed, vehicle load and wheel radius; The motor torque is obtained according to the motor speed, the motor voltage and the motor external characteristic curve; Obtaining a mechanical braking torque according to a difference between the total required braking torque and the motor braking torque; The friction coefficient of the lining of the mechanical brake device is obtained according to the mechanical braking torque and the hydraulic pressure, the lining radius of the mechanical brake device, and the lining area of ​​the mechanical brake device.

16. The vehicle brake control device according to claim 12, characterized in that: When the motor reverse braking is performed, the electric energy generated by the motor is used to drive the cooling unit to perform a cooling operation on the motor.

17. The vehicle brake control device according to claim 16, characterized in that: The cooling operation includes: When a braking command is received, the motor thermal power is calculated according to the obtained motor current and the motor current; The cooling unit is controlled to perform a cooling operation according to the motor thermal power.

18. The vehicle brake control device according to claim 17, characterized in that: The cooling operation further includes controlling a cooling unit to perform a cooling operation on the motor according to the acquired temperature of the motor.

19. The vehicle brake control device according to claim 12, characterized in that: When performing energy recovery braking, when the total required braking force is greater than the maximum braking force that can be provided by the energy recovery braking, mechanical braking is also performed, and the braking force generated by the mechanical braking is superimposed on the braking force generated by the energy recovery braking.

20. The vehicle brake control device according to claim 12, characterized in that: When performing motor reverse braking and mechanical braking, initially the braking force of the motor reverse braking is greater than the braking force of the mechanical braking, and the braking force of the motor reverse braking decreases as the speed decreases, while the braking force of the mechanical braking increases as the speed decreases.

21. The vehicle brake control device according to claim 12, characterized in that: When the power level of the battery is less than a first power level, the energy recovery braking is performed.

22. The vehicle brake control device according to claim 12, characterized in that: The vehicle is an electric truck.

23. A vehicle braking system, characterized in that: include: Motor, mechanical brake device, battery, vehicle brake control device, speed acquisition device and multiple control switches, The vehicle brake control device is used to control the connection and disconnection of the control switch according to the vehicle speed obtained in real time by the speed acquisition device, thereby controlling the vehicle brake, wherein: When the vehicle speed is greater than the first speed, energy recovery braking is performed, the vehicle speed control switch is located at the first speed limit, the energy recovery switch is located at the first energy recovery limit, the brake switch is connected, the motor and the battery form a series circuit, the motor generates electricity to recover energy, and the battery is charged; When the vehicle speed is less than the first speed and greater than the second speed, the motor reverse braking and the mechanical braking are performed, the vehicle speed control switch is located at the second speed limit, the energy recovery switch is located at the second energy recovery limit, the brake switch is disconnected, and the braking force supplement switch is connected, the motor and the battery form a series circuit, the mechanical brake device and the motor form a parallel circuit, the braking force generated by the motor reverse braking and the braking force generated by the mechanical brake are superimposed, and the electric energy generated by the motor is consumed by the power consumption device; When the vehicle speed is less than the second speed, mechanical braking is performed, the vehicle speed control switch is located at the third speed limit, the mechanical braking device and the battery form a series circuit, and the braking force is generated by the mechanical braking.

24. The system according to claim 23, characterized in that It also includes a temperature control switch for a mechanical brake device. When mechanical braking is performed, when the temperature of the mechanical brake device exceeds a predetermined temperature, the motor reverse braking is also performed. The temperature control switch for the mechanical brake device is connected, and the mechanical brake device also forms a parallel circuit with the motor. The braking force generated by the motor reverse braking and the braking force generated by the mechanical brake are superimposed.

25. The system according to claim 24, characterized in that When the braking force generated by the motor reverse braking and the braking force generated by the mechanical braking are superimposed, the braking force of the motor reverse braking increases as the speed decreases, and the braking force of the mechanical braking decreases as the speed decreases.

26. The system according to claim 23 or 24, characterized in that Based on the corresponding relationship between the temperature of the mechanical brake device and the friction coefficient of the lining of the mechanical brake device, the temperature of the mechanical brake device is obtained by calculating the friction coefficient, and the friction coefficient is obtained by the following method: The total required braking torque is obtained according to the product of vehicle speed, vehicle load and wheel radius; The braking torque of the motor is obtained according to the motor speed, the motor voltage and the motor external characteristic curve; Obtaining a mechanical braking torque according to a difference between the total required braking torque and the motor braking torque; The friction coefficient of the lining of the mechanical brake device is obtained according to the mechanical braking torque and the hydraulic pressure, the lining radius of the mechanical brake device, and the lining area of ​​the mechanical brake device.

27. The system according to claim 23, characterized in that It also includes a cooling device. When the motor reverse braking is performed, the motor and the cooling device form a series circuit, and the electric energy generated by the motor is used to drive the cooling unit to perform a cooling operation on the motor.

28. The system according to claim 27, characterized in that Also includes: The motor control device is used to obtain the current of the motor when a braking command is received. The vehicle braking control device calculates the motor thermal power based on the motor current. The cooling device controls the cooling unit to perform cooling operation on the motor based on the motor thermal power.

29. The system according to claim 28, characterized in that Also includes: Temperature sensor, used to obtain the temperature of the motor; A cooling control device is used to control the cooling device to perform a cooling operation on the motor according to the temperature.

30. The system of claim 23, wherein: When performing energy recovery braking, when the total required braking force is greater than the maximum braking force that can be provided by the energy recovery braking, mechanical braking is also performed, the braking force supplement switch is connected, and the motor also forms a parallel circuit with the mechanical braking device, and the braking force generated by the mechanical braking is superimposed on the braking force generated by the energy recovery braking.

31. The system according to claim 23, characterized in that When performing motor reverse braking and mechanical braking, initially the braking force of the motor reverse braking is greater than the braking force of the mechanical braking, and the braking force of the motor reverse braking decreases as the speed decreases, while the braking force of the mechanical braking increases as the speed decreases.

32. The system according to claim 23, characterized in that When the battery power is greater than the first power, mechanical braking is performed, the battery power control switch is located at the second power limit, and the battery and the mechanical braking device form a series circuit.

33. The system according to claim 23, characterized in that The vehicle is an electric truck.

34. A computing device, characterized in that include: bus; A communication interface connected to the bus; at least one processor connected to the bus; as well as At least one memory is connected to the bus and stores program instructions, and when the program instructions are executed by the at least one processor, the at least one processor executes the method according to any one of claims 1 to 11.

35. A computer-readable storage medium having program instructions stored thereon, characterized in that: When the program instructions are executed by a computer, the computer is caused to perform the method according to any one of claims 1 to 11.

36. A computer program, characterized in that The method comprises program instructions, which, when executed by a computer, enable the computer to execute the method according to any one of claims 1 to 11.

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