A pure electric vehicle electric braking method, device, equipment and medium

Abstract

The present application relates to the technical field of electric vehicle drive motor control, and provides a pure electric vehicle electric braking method, device, equipment and medium to obtain electric braking torque, current battery state of charge, and allowed charging power; if the current state of charge is a low battery state of charge, the electric braking torque and allowed charging power are input into a pre-constructed first braking current calculation model to obtain a first braking current; if the current state of charge is a high battery state of charge, and the allowed charging power is not zero, the electric braking torque and allowed charging power are input into a pre-constructed second braking current calculation model to obtain a second braking current. The present application redistributes the braking current to the motor under the same electric braking torque; electric braking and energy recovery are performed under a low battery state of charge, and electric braking and energy recovery can still be performed according to the allocated braking current without changing the electric braking torque under a high battery state of charge.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicle drive motor control, and in particular to a method, device, equipment and medium for electric braking of a pure electric vehicle. Background Art

[0002] Faced with increasingly severe energy and environmental challenges, energy-saving and new energy vehicles are becoming a hot topic of research. The development of these vehicles, particularly pure electric vehicles with zero pollution and emissions, is not only of great significance to my country's energy security and environmental protection but also represents a future trend in the automotive sector. Unlike traditional fuel-powered vehicles, the drive motor not only converts electrical energy into mechanical energy to propel the vehicle, but also has the ability to convert mechanical energy into electrical energy for electric braking and charging the power battery – a unique energy recovery feature of pure electric vehicles.

[0003] Currently, energy recovery in pure electric vehicles (BEVs) mostly utilizes a brake torque-based distribution and control method. This method first calculates the total braking torque required based on the vehicle's state and the change in brake pedal opening. The braking torque is then allocated to the drive motor and hydraulic system based on the battery's State of Charge (SOC), the available state of charge remaining in the battery. Chinese patent CN109941245A discloses a braking force distribution method for electric vehicles. This method uses braking intensity, battery SOC, and total braking force required as inputs, and outputs the ratio of regenerative braking force to front wheel braking force via a fuzzy controller. Chinese patent CN110667394A discloses a battery SOC-based braking recovery system, method, and electric vehicle, proposing an energy recovery method for high SOC conditions and power loss. In both of the above existing technologies, the braking strategy is completely formulated by the VCU (Vehicle Control Unit), and the MCU (Microprocessor Unit, Motor Controller) only passively executes torque output. In addition, the torque distribution strategy in the high SOC state of the battery does not perform energy recovery (electric braking), which will cause inconsistent driving feeling to the driver and affect the driving experience. Even in the case of high SOC, when sliding backward on a slope, the electric braking torque is limited and the driver must use the brake pedal to adjust the braking force. There are certain safety operation risks in stopping the car and applying a certain amount of drive before starting. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a pure electric vehicle electric braking method, device, equipment and medium to solve the problems in the prior art of inconsistent torque distribution strategy and safety operation risks under high SOC state.

[0005] To achieve the above-mentioned and other related purposes, the present application provides an electric braking method for a pure electric vehicle, the method comprising:

[0006] Obtain electric braking torque, current battery state of charge, and allowed charging power;

[0007] If the current state of charge is a low battery state of charge, inputting the electric braking torque and the allowed charging power into a pre-established first braking current calculation model to obtain a first braking current, wherein the first braking current is used to control the motor to perform low battery state of charge braking and perform electric braking energy recovery;

[0008] If the current state of charge is a high battery state of charge and the allowable charging power is not zero, the electric braking torque and the allowable charging power are input into a pre-constructed second braking current calculation model to obtain a second braking current, which is used to control the motor to perform high battery state of charge braking and electric braking energy recovery.

[0009] In one embodiment of the present application, the vehicle controller obtains the current braking demand torque according to the vehicle state and the change in the brake pedal opening, and distributes the current braking demand torque according to a preset torque distribution strategy to obtain the electric braking torque.

[0010] In one embodiment of the present application, after obtaining the electric braking torque, the current battery state of charge, and the allowed charging power, the following steps are further included:

[0011] Obtaining a combination of a d-axis current and a q-axis current at a calibrated motor rotational angular velocity, and an output torque corresponding to the combination of the d-axis current and the q-axis current;

[0012] performing difference processing on the combination of the d-axis current and the q-axis current, performing difference processing on the output torque, and determining different combinations of the d-axis current and the q-axis current corresponding to the same output torque;

[0013] An equal torque curve is drawn according to the same output torque and different combinations of d-axis current and q-axis current corresponding to the same output torque. The equal torque curve is used to obtain the first braking current or the second braking current in combination with the electric braking torque.

[0014] In one embodiment of the present application, the first braking current includes a d-axis first braking current and a q-axis first braking current, and the first braking current calculation model is represented by:

[0015] Among them, P em is the calibrated electromagnetic power, ω m To calibrate the motor angular velocity, P cu1 is the copper loss at low battery state of charge, PFe To calibrate the iron loss, P mec is the calibrated mechanical loss and stray loss, P o1 is the energy recovery power at low battery charge state, I L1 is the effective value of the motor phase current at low battery charge state, R is the motor stator resistance, T e is the electric braking torque, p n is the number of motor pole pairs, is the permanent magnet flux of the motor, L d is the motor d-axis inductance, L q is the motor q-axis inductance, i d1 is the first braking current of the d-axis at low battery charge state, i q1 is the first braking current of the q axis at low battery charge state, i d1 and i q1 Based on the electric braking torque, I L1 and pre-built isotorque curves are obtained.

[0016] In one embodiment of the present application, the second braking current includes a d-axis second braking current and a q-axis second braking current, and the second braking current calculation model is represented as follows:

[0017] Among them, P em is the calibrated electromagnetic power, ω m To calibrate the motor angular velocity, P cu2 is the copper loss at high battery state of charge, P Fe To calibrate the iron loss, P mec is the calibrated mechanical loss and stray loss, P o2 is the energy recovery power at high battery state of charge, I L2 is the effective value of the motor phase current at high battery charge state, R is the motor stator resistance, T e is the electric braking torque, p n is the number of motor pole pairs, is the permanent magnet flux of the motor, L d is the motor d-axis inductance, L q is the motor q-axis inductance, i d2 is the d-axis second braking current at high battery state of charge, i q2 is the q-axis second braking current at high battery state of charge, i d2 and i q2 Based on the electric braking torque, I L2 and pre-built isotorque curves are obtained.

[0018] In one embodiment of the present application, after obtaining the electric braking torque, the current battery state of charge, and the allowed charging power, the method further includes:

[0019] If the current state of charge is a high battery state of charge and the allowed charging power is zero, the electric braking torque is input into a pre-built third braking current calculation model to obtain a third braking current, and the third braking current is used to control the motor to perform high battery state of charge braking.

[0020] In one embodiment of the present application, the third braking current includes a d-axis third braking current and a q-axis third braking current, and the representation of the third braking current calculation model includes:

[0021] Among them, P em is the calibrated electromagnetic power, ω m To calibrate the motor angular velocity, P cu3 is the copper loss at high battery state of charge, P Fe To calibrate the iron loss, P mec is the calibrated mechanical loss and stray loss, I L3 is the effective value of the motor phase current at high battery charge state, R is the motor stator resistance, T e is the electric braking torque, p n is the number of motor pole pairs, is the permanent magnet flux of the motor, L d is the motor d-axis inductance, L q is the motor q-axis inductance, i d3 is the d-axis second braking current at high battery state of charge, i q3 is the q-axis third braking current at high battery state of charge, i d3 and i q3 Based on the electric braking torque, I L3 and pre-built isotorque curves are obtained.

[0022] In one embodiment of the present application, an electric brake device for a pure electric vehicle is further provided, the device comprising:

[0023] Data acquisition module, used to obtain electric braking torque, current battery state of charge, and allowed charging power;

[0024] a low battery state of charge braking module, configured to input the electric braking torque and the allowable charging power into a pre-established first braking current calculation model to obtain a first braking current if the current state of charge is a low battery state of charge, wherein the first braking current is used to control the motor to perform low battery state of charge braking and perform electric braking energy recovery;

[0025] A high battery state of charge braking module is used to input the electric braking torque and the allowed charging power into a pre-built second braking current calculation model if the current state of charge is a high battery state of charge and the allowed charging power is not zero, to obtain a second braking current. The second braking current is used to control the motor to perform high battery state of charge braking and perform electric braking energy recovery.

[0026] In one embodiment of the present application, an electronic device is further provided, comprising:

[0027] one or more processors;

[0028] The storage device is used to store one or more programs. When the one or more programs are executed by the one or more processors, the electronic device implements the electric braking method of the pure electric vehicle as described above.

[0029] In one embodiment of the present application, a computer-readable storage medium is further provided, on which a computer program is stored. When the computer program is executed by a processor of a computer, the computer executes the electric braking method of a pure electric vehicle as described above.

[0030] Beneficial effects of the present invention:

[0031] First, the electric braking torque, the current battery state of charge, and the allowed charging power are obtained; if the current state of charge is a low battery state of charge, the electric braking torque and the allowed charging power are input into a pre-constructed first braking current calculation model to obtain a first braking current, which is used to control the motor to perform low battery state of charge braking and perform electric braking energy recovery; if the current state of charge is a high battery state of charge, and the allowed charging power is not zero, the electric braking torque and the allowed charging power are input into a pre-constructed second braking current calculation model to obtain a second braking current, which is used to control the motor to perform high battery state of charge braking and perform electric braking energy recovery. This application obtains the electric braking torque, the current battery state of charge, and the allowed charging power through a motor controller, and redistributes the braking current to the motor under the same electric braking torque; electric braking and energy recovery are performed under a low battery state of charge, and there is no need to change the electric braking torque under a high battery state of charge, and electric braking and energy recovery can still be performed according to the allocated braking current. In a high-charge state, there is no need to change the electric braking torque, which improves the driving experience and does not overcharge the battery. When starting on a hill, you can step on the accelerator pedal to naturally switch from electric braking to forward drive, simplifying the hill start operation and avoiding safety risks.

[0032] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are incorporated into and constitute a part of the specification, illustrating embodiments consistent with the present application and, together with the specification, serving to explain the principles of the present application. Obviously, the drawings described below are merely some embodiments of the present application, and a person of ordinary skill in the art can derive other drawings based on these drawings without inventive effort. In the accompanying drawings:

[0034] Figure 1 1 is a schematic diagram of an implementation environment of an electric braking method for a pure electric vehicle according to an exemplary embodiment of the present application;

[0035] Figure 2 is a flow chart of an electric braking method for a pure electric vehicle shown in an exemplary embodiment of the present application;

[0036] Figure 3 is a schematic diagram of power generation flow shown in an exemplary embodiment of the present application;

[0037] Figure 4 is a schematic diagram of a combination of d-axis current and q-axis current shown in an exemplary embodiment of the present application;

[0038] Figure 5 is a schematic diagram of an equivalent torque curve and braking current distribution shown in an exemplary embodiment of the present application;

[0039] Figure 6 is a current closed-loop control block diagram shown in an exemplary embodiment of the present application;

[0040] Figure 7 is a block diagram of an electric brake device for a pure electric vehicle shown in an exemplary embodiment of the present application;

[0041] Figure 8 A schematic structural diagram of a computer system suitable for an electronic device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0042] The following describes the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the various details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are intended only to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0043] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0044] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring the embodiments of the present invention.

[0045] Figure 1 FIG. 1 is a schematic diagram of an implementation environment of an electric braking method for a pure electric vehicle according to an exemplary embodiment of the present application. Figure 1 As shown, the implementation environment includes a power battery, a BMS (Battery Management System), a vehicle controller, a motor controller, a vehicle speed, and a brake pedal.

[0046] The vehicle controller calculates the current total braking torque requirement based on the vehicle state, speed, and brake pedal opening, and outputs the electric braking torque through the torque distribution strategy, which is Figure 1 The electric braking force in the vehicle. When executing electric braking torque, the motor controller distributes the braking current based on the electric braking torque issued by the vehicle controller, the allowable charging power transmitted by the battery management system, and the state of charge (SOC). It then generates a braking voltage based on the braking current to control the motor for electric braking and electric braking energy recovery.

[0047] For example, the electric braking method of the pure electric vehicle in the embodiment of the present application can be performed by Figure 1 The motor controller in the embodiment implements the following steps: obtaining electric braking torque, current battery state of charge, and allowed charging power; if the current state of charge is a low battery state of charge, inputting the electric braking torque and allowed charging power into a pre-constructed first braking current calculation model to obtain a first braking current, which is used to control the motor to perform low battery state of charge braking and perform electric braking energy recovery; if the current state of charge is a high battery state of charge and the allowed charging power is not zero, inputting the electric braking torque and allowed charging power into a pre-constructed second braking current calculation model to obtain a second braking current, which is used to control the motor to perform high battery state of charge braking and perform electric braking energy recovery.

[0048] In order to solve the problems in the prior art of inconsistent torque distribution strategies and safety operation risks under high SOC conditions, the embodiments of the present application respectively propose a pure electric vehicle electric braking method, a pure electric vehicle electric braking device, an electronic device, and a computer-readable storage medium. These embodiments will be described in detail below.

[0049] See also Figure 2 , Figure 2 This is a flow chart of an exemplary embodiment of the present application showing a method for electric braking of a pure electric vehicle. This method can be applied to Figure 1 It should be understood that the method can also be applied to other exemplary implementation environments and specifically executed by devices in other implementation environments, and this embodiment does not limit the implementation environment to which the method is applicable.

[0050] like Figure 2 As shown, in an exemplary embodiment, the electric braking method of a pure electric vehicle includes at least steps S210 to S230, which are described in detail as follows:

[0051] In step S210 , the electric braking torque, the current battery state of charge, and the allowed charging power are obtained.

[0052] Exemplarily, the vehicle controller receives a brake pedal signal and distributes electric braking torque to the motor controller. After receiving the electric braking torque, the motor controller adopts a corresponding current distribution strategy according to the SOC state and the allowed charging power.

[0053] In one embodiment of the present application, the vehicle controller obtains the current braking demand torque according to the vehicle state and the change in the brake pedal opening, and distributes the current braking demand torque according to a preset torque distribution strategy to obtain the electric braking torque.

[0054] In step S220, if the current state of charge is a low battery state of charge, the electric braking torque and the allowed charging power are input into a pre-constructed first braking current calculation model to obtain a first braking current, which is used to control the motor to perform low battery state of charge braking and perform electric braking energy recovery.

[0055] In one embodiment of the present application, the first braking current includes a d-axis first braking current and a q-axis first braking current, and the representation of the first braking current calculation model includes:

[0056] Among them, P em is the calibrated electromagnetic power, ω m To calibrate the motor angular velocity, P cu1 is the copper loss at low battery state of charge, P Fe To calibrate the iron loss, Pmec is the calibrated mechanical loss and stray loss, P o1 is the energy recovery power at low battery charge state, I L1 is the effective value of the motor phase current at low battery charge state, R is the motor stator resistance, T e is the electric braking torque, p n is the number of motor pole pairs, is the permanent magnet flux of the motor, L d is the motor d-axis inductance, L q is the motor q-axis inductance, i d1 is the first braking current of the d-axis at low battery charge state, i q1 is the first braking current of the q axis at low battery charge state, i d1 and i q1 Based on the electric braking torque, I l1 and pre-built isotorque curves are obtained.

[0057] It should be noted that, see Figure 3 , Figure 3 FIG. 1 is a schematic diagram of power generation flow shown in an exemplary embodiment of the present application. Figure 3 and P in the first braking current calculation model em =T e ω m =P cu1 +P Fe +P mec +P o1 It can be seen that when the electromagnetic power is constant, the copper loss P cu1 Increase, P o1 The smaller it is, the embodiment of the present application is based on this phenomenon so that the motor controller adjusts the output power by reasonably allocating the current operating point.

[0058] In step S230, if the current state of charge is a high battery state of charge and the allowable charging power is not zero, the electric braking torque and the allowable charging power are input into a pre-constructed second braking current calculation model to obtain a second braking current, which is used to control the motor to perform high battery state of charge braking and electric braking energy recovery.

[0059] In one embodiment of the present application, the second braking current includes a d-axis second braking current and a q-axis second braking current, and the second braking current calculation model is represented as follows:

[0060] Among them, P em is the calibrated electromagnetic power, ω m To calibrate the motor angular velocity, P cu2 is the copper loss at high battery state of charge, PFe To calibrate the iron loss, P mec is the calibrated mechanical loss and stray loss, P o2 is the energy recovery power at high battery state of charge, I L2 is the effective value of the motor phase current at high battery charge state, R is the motor stator resistance, T e is the electric braking torque, p n is the number of motor pole pairs, is the permanent magnet flux of the motor, L d is the motor d-axis inductance, L q is the motor q-axis inductance, i d2 is the d-axis second braking current at high battery state of charge, i q2 is the q-axis second braking current at high battery state of charge, i d2 and i q2 Based on the electric braking torque, I L2 and pre-built isotorque curves are obtained.

[0061] As can be seen from steps S210 to S230 above, the solution proposed in this embodiment uses the motor controller to obtain the electric braking torque, the current battery state of charge, and the allowed charging power, and redistributes the braking current to the motor while maintaining the same electric braking torque. Electric braking and energy recovery are performed at low battery states of charge, while at high battery states of charge, electric braking and energy recovery can still be performed based on the allocated braking current without changing the electric braking torque. This eliminates the need to change the electric braking torque at high battery states, improving the driving experience and preventing battery overcharge. Furthermore, when starting on a hill, the accelerator pedal can be pressed to automatically switch from electric braking to forward drive, simplifying hill starts and avoiding safety risks.

[0062] In one embodiment of the present application, Figure 2 Before obtaining the electric braking torque, the current battery state of charge, and the allowed charging power in step S210, the following steps are also included:

[0063] Obtaining a combination of a d-axis current and a q-axis current at a calibrated motor rotational angular velocity, and an output torque corresponding to the combination of the d-axis current and the q-axis current;

[0064] performing difference processing on the combination of the d-axis current and the q-axis current, performing difference processing on the output torque, and determining different combinations of the d-axis current and the q-axis current corresponding to the same output torque;

[0065] An equal torque curve is drawn according to the same output torque and different combinations of d-axis current and q-axis current corresponding to the same output torque. The equal torque curve is used to obtain the first braking current or the second braking current in combination with the electric braking torque.

[0066] For example, the d-axis current and q-axis current combination under the calibrated motor rotational angular velocity can be a current combination sent by the measurement and control computer to the motor controller at a fixed speed. Figure 4 , Figure 4 FIG is a schematic diagram showing a combination of d-axis current and q-axis current according to an exemplary embodiment of the present application. Figure 4 It can be seen that different combinations of d-axis current and q-axis current will form different effective values of the motor phase current.

[0067] In one embodiment of the present application, the first braking current calculation model and the second braking current calculation model It can be seen that the same electric braking torque will correspond to different combinations of d-axis current and q-axis current. Figure 5 , Figure 5 Schematic diagram of an equivalent torque curve and braking current distribution shown in an exemplary embodiment of the present application. Figure 5 In the figure, T1, T2, and T3 are equal torque lines. Any current combination point (i d 、i q ) can output the same torque. When in the low SOC state, the MCU distributes the current operating point to the minimum current point on each equal torque curve (such as point A in the figure) according to the different electric braking torques issued by the VCU, so as to minimize copper loss and recover more energy. In the high SOC state, the VCU adopts the same braking torque distribution strategy, and the motor controller MCU receives the same electric braking torque. It adjusts the current operating point to the corresponding current operating point according to the charging power allowed by the BMS (such as point B in the figure). If the allowed charging power of the BMS is zero, the current operating point is distributed to the maximum current point that the motor controller can withstand (such as point C in the figure), so that the energy is lost to the motor end.

[0068] In one embodiment of the present application, Figure 2 After obtaining the electric braking torque, the current battery state of charge, and the allowed charging power in step S210, the following steps are included:

[0069] If the current state of charge is a high battery state of charge and the allowed charging power is zero, the electric braking torque is input into a pre-built third braking current calculation model to obtain a third braking current, and the third braking current is used to control the motor to perform high battery state of charge braking.

[0070] In one embodiment of the present application, the third braking current includes a d-axis third braking current and a q-axis third braking current, and the representation of the third braking current calculation model includes:

[0071] Among them, P emis the calibrated electromagnetic power, ω m To calibrate the motor angular velocity, P cu3 is the copper loss at high battery state of charge, P Fe To calibrate the iron loss, P mec is the calibrated mechanical loss and stray loss, I L3 is the effective value of the motor phase current at high battery charge state, R is the motor stator resistance, T e is the electric braking torque, p n is the number of motor pole pairs, is the permanent magnet flux of the motor, L d is the motor d-axis inductance, L q is the motor q-axis inductance, i d3 is the d-axis second braking current at high battery state of charge, i q3 is the q-axis third braking current at high battery state of charge, i d3 and i q3 Based on the electric braking torque, I L3 and pre-built isotorque curves are obtained.

[0072] In one embodiment of the present application, when the vehicle controller issues different electric braking torques, the motor controller adjusts the braking current in the corresponding model according to the current SOC and the maximum allowed charging power. After the motor controller obtains the braking current, it determines the braking voltage based on the braking current and transmits the braking voltage to the motor to output the corresponding torque, completing the current closed-loop control. Figure 6 , Figure 6 is a current closed-loop control block diagram illustrating an exemplary embodiment of the present application. Figure 6 In the process, the d-axis braking current and the q-axis braking circuit form a braking voltage, which controls the motor to achieve torque output.

[0073] Figure 7 This is a block diagram of an electric brake device for a pure electric vehicle shown in an exemplary embodiment of the present application. The device can be applied to Figure 1 The device may also be applicable to other exemplary implementation environments and specifically configured in other devices. This embodiment does not limit the implementation environment to which the device is applicable.

[0074] like Figure 7 As shown, the exemplary electric brake device of a pure electric vehicle includes:

[0075] The data acquisition module 701 is used to obtain the electric braking torque, the current battery state of charge, and the allowed charging power;

[0076] a low battery state of charge braking module 702 for inputting the electric braking torque and the allowable charging power into a pre-established first braking current calculation model to obtain a first braking current if the current state of charge is a low battery state of charge. The first braking current is used to control the motor to perform low battery state of charge braking and perform electric braking energy recovery;

[0077] The high battery state of charge braking module 703 is used to input the electric braking torque and the allowed charging power into a pre-built second braking current calculation model if the current state of charge is a high battery state of charge and the allowed charging power is not zero, to obtain a second braking current. The second braking current is used to control the motor to perform high battery state of charge braking and perform electric braking energy recovery.

[0078] In this exemplary electric braking system for a pure electric vehicle, the motor controller obtains the electric braking torque, current battery state of charge, and permitted charging power, redistributing the braking current to the motor while maintaining the same electric braking torque. Electric braking and energy recovery are performed at low battery states of charge, while at high battery states of charge, electric braking and energy recovery continue according to the allocated braking current without changing the electric braking torque. This eliminates the need to change the electric braking torque at high battery states, improving the driving experience and preventing battery overcharge. Furthermore, when starting on a hill, the accelerator pedal can be pressed to automatically switch from electric braking to forward drive, simplifying hill starts and avoiding safety risks.

[0079] It should be noted that the electric braking device for a pure electric vehicle provided in the above-mentioned embodiment and the electric braking method for a pure electric vehicle provided in the above-mentioned embodiment are based on the same concept. The specific manner in which each module and unit performs operations has been described in detail in the method embodiment and will not be repeated here. In actual applications, the electric braking device for a pure electric vehicle provided in the above-mentioned embodiment can, as needed, allocate the above-mentioned functions to different functional modules, that is, divide the internal structure of the device into different functional modules to complete all or part of the functions described above, and this is not limited here.

[0080] An embodiment of the present application also provides an electronic device, comprising: one or more processors; a storage device for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the electronic device implements the pure electric vehicle electric braking method provided in the above-mentioned embodiments.

[0081] Figure 8 The following is a schematic diagram showing the structure of a computer system of an electronic device suitable for an embodiment of the present application. Figure 8 The computer system 800 of the electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0082] like Figure 8 As shown, the computer system 800 includes a central processing unit (CPU) 801, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 802 or the program loaded from the storage part 808 into the random access memory (RAM) 803, such as executing the method described in the above embodiment. Various programs and data required for system operation are also stored in the RAM 803. The CPU 801, ROM 802 and RAM 803 are connected to each other via a bus 804. An input / output (I / O) interface 805 is also connected to the bus 804.

[0083] The following components are connected to the I / O interface 805: an input section 806 including a keyboard, a mouse, and the like; an output section 807 including devices such as a cathode ray tube (CRT), a liquid crystal display (LCD), and a speaker; a storage section 808 including a hard disk and the like; and a communication section 809 including a network interface card such as a LAN (Local Area Network) card or a modem. The communication section 809 performs communication processing via a network such as the Internet. A drive 810 is also connected to the I / O interface 805 as needed. Removable media 811, such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, is installed in the drive 810 as needed, so that computer programs read therefrom can be installed into the storage section 808 as needed.

[0084] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a computer program for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via the communication section 809, and / or installed from a removable medium 811. When the computer program is executed by the central processing unit (CPU) 801, the various functions defined in the system of the present application are executed.

[0085] It should be noted that the computer-readable medium shown in the embodiments of the present application can be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium can be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, which carries a computer-readable computer program. This propagated data signal can take a variety of forms, including but not limited to an electromagnetic signal, an optical signal, 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 that can transmit, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. A computer program embodied on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, or any suitable combination thereof.

[0086] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. Among them, each box in the flowchart or block diagram can represent a module, program segment, or part of the code, and the above-mentioned module, program segment, or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0087] The units involved in the embodiments described in this application may be implemented by software or hardware, and the units described may also be set in a processor. In some cases, the names of these units do not constitute limitations on the units themselves.

[0088] Another aspect of the present application provides a computer-readable storage medium having a computer program stored thereon. When executed by a computer processor, the computer program causes the computer to perform the above-described electric braking method for a pure electric vehicle. The computer-readable storage medium may be included in the electronic device described in the above embodiments, or may exist independently and not be incorporated into the electronic device.

[0089] Another aspect of the present application further provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the electric braking method for a pure electric vehicle provided in each of the above embodiments.

[0090] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, any equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A pure electric vehicle electric braking method, characterized in that: The method comprises: Obtain electric braking torque, current battery state of charge, and allowed charging power; If the current state of charge is a low battery state of charge, inputting the electric braking torque and the allowed charging power into a pre-established first braking current calculation model to obtain a first braking current, wherein the first braking current is used to control the motor to perform low battery state of charge braking and perform electric braking energy recovery; If the current state of charge is a high battery state of charge and the allowed charging power is not zero, inputting the electric braking torque and the allowed charging power into a pre-established second braking current calculation model to obtain a second braking current, wherein the second braking current is used to control the motor to perform high battery state of charge braking and perform electric braking energy recovery; If the current state of charge is a high battery state of charge and the allowed charging power is zero, the electric braking torque is input into a pre-established third braking current; a calculation model is used to obtain a third braking current, and the third braking current is used to control the motor to perform high battery state of charge braking; the third braking current calculation model includes: P em =T e ω m =P cu3 +P Fe +P mec Among them, P em To calibrate the electromagnetic power, T e is the electric braking torque, ω m To calibrate the motor angular velocity, P cu3 is the copper loss at high battery state of charge, P Fe To calibrate the iron loss, P mec is the nominal mechanical loss and stray loss.

2. The electric braking method for a pure electric vehicle according to claim 1, characterized in that: The vehicle controller obtains the current braking demand torque according to the vehicle state and the change in the brake pedal opening, and distributes the current braking demand torque according to a preset torque distribution strategy to obtain the electric braking torque.

3. The electric braking method for a pure electric vehicle according to claim 1, characterized in that: After obtaining the electric brake torque, current battery state of charge, and allowed charging power, it also includes: Obtaining a combination of a d-axis current and a q-axis current at a calibrated motor rotational angular velocity, and an output torque corresponding to the combination of the d-axis current and the q-axis current; performing difference processing on the combination of the d-axis current and the q-axis current, performing difference processing on the output torque, and determining different combinations of the d-axis current and the q-axis current corresponding to the same output torque; An equal torque curve is drawn according to the same output torque and different combinations of d-axis current and q-axis current corresponding to the same output torque. The equal torque curve is used to obtain the first braking current or the second braking current in combination with the electric braking torque.

4. The electric braking method for a pure electric vehicle according to claim 3, characterized in that: The first braking current includes a d-axis first braking current and a q-axis first braking current. The first braking current calculation model is expressed in the following manner: Among them, P em is the calibrated electromagnetic power, ω m To calibrate the motor angular velocity, P cu1 is the copper loss at low battery state of charge, P Fe To calibrate the iron loss, P mec is the calibrated mechanical loss and stray loss, P o1 is the energy recovery power at low battery charge state, I L1 is the effective value of the motor phase current at low battery charge state, R is the motor stator resistance, T e is the electric braking torque, p n is the number of motor pole pairs, is the permanent magnet flux of the motor, L d is the motor d-axis inductance, L q is the motor q-axis inductance, i d1 is the first braking current of the d-axis at low battery charge state, i q1 is the first braking current of the q axis at low battery charge state, i d1 and i q1 Based on the electric braking torque, I L1 and pre-built isotorque curves are obtained.

5. The electric braking method for a pure electric vehicle according to claim 1, characterized in that: The second braking current includes a d-axis second braking current and a q-axis second braking current. The second braking current calculation model is expressed as follows: Among them, P em is the calibrated electromagnetic power, ω m To calibrate the motor angular velocity, P cu2 is the copper loss at high battery state of charge, P Fe To calibrate the iron loss, P mec is the calibrated mechanical loss and stray loss, P o2 is the energy recovery power at high battery state of charge, I L2 is the effective value of the motor phase current at high battery charge state, R is the motor stator resistance, T e is the electric braking torque, p n is the number of motor pole pairs, is the permanent magnet flux of the motor, L d is the motor d-axis inductance, L q is the motor q-axis inductance, i d2 is the d-axis second braking current at high battery state of charge, i q2 is the q-axis second braking current at high battery state of charge, i d2 and i q2 Based on the electric braking torque, I L2 and pre-built isotorque curves are obtained.

6. The electric braking method for a pure electric vehicle according to claim 1, characterized in that: The third braking current includes a d-axis third braking current and a q-axis third braking current. The third braking current calculation model is represented as follows: Among them, P em is the calibrated electromagnetic power, ω m To calibrate the motor angular velocity, P cu3 is the copper loss at high battery state of charge, P Fe To calibrate the iron loss, P mec is the calibrated mechanical loss and stray loss, I L3 is the effective value of the motor phase current at high battery charge state, R is the motor stator resistance, T e is the electric braking torque, p n is the number of motor pole pairs, is the permanent magnet flux of the motor, L d is the motor d-axis inductance, L q is the motor q-axis inductance, i d3 is the d-axis second braking current at high battery state of charge, i q3 is the q-axis third braking current at high battery state of charge, i d3 and i q3 Based on the electric braking torque, I L3 and pre-built isotorque curves are obtained.

7. An electric brake device for a pure electric vehicle, characterized in that: The device comprises: Data acquisition module, used to obtain electric braking torque, current battery state of charge, and allowed charging power; a low battery state of charge braking module, configured to input the electric braking torque and the allowable charging power into a pre-established first braking current calculation model to obtain a first braking current if the current state of charge is a low battery state of charge, wherein the first braking current is used to control the motor to perform low battery state of charge braking and perform electric braking energy recovery; A high battery state of charge braking module is configured to input the electric braking torque and the allowed charging power into a pre-established second braking current calculation model to obtain a second braking current if the current state of charge is a high battery state of charge and the allowed charging power is not zero. The second braking current is used to control the motor to perform high battery state of charge braking and perform electric braking energy recovery. If the current state of charge is a high battery state of charge and the allowed charging power is zero, the electric braking torque is input into a pre-established third braking current calculation model to obtain a third braking current. The third braking current is used to control the motor to perform high battery state of charge braking. The representation of the third braking current calculation model includes: P em =T e ω m =P cu3 +P Fe +P mec Among them, P em To calibrate the electromagnetic power, T e is the electric braking torque, ω m To calibrate the motor angular velocity, P cu3 is the copper loss at high battery state of charge, P Fe To calibrate the iron loss, P mec is the nominal mechanical loss and stray loss.

8. An electronic device, characterized in that: The electronic device comprises: one or more processors; A storage device for storing one or more programs, which, when executed by the one or more processors, enables the electronic device to implement the electric braking method for a pure electric vehicle as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that A computer program is stored thereon, and when the computer program is executed by a processor of a computer, the computer is caused to execute the electric braking method for a pure electric vehicle as claimed in any one of claims 1 to 6.

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