Domain controller for electric vehicle, control method electric vehicle

Abstract

A domain controller for electric vehicles is provided, comprising a vehicle control module, an energy management module, and a motor control module. The vehicle control module uses external sensors to sample the accelerator and brake pedal opening information and motor speed information in real time. The energy management module calculates the battery's state of charge (SOC) value. The motor control module calculates the motor torque output and energy feedback power based on the opening information, motor speed information, and battery SOC value. An electric vehicle incorporating this domain controller is also provided. This invention significantly simplifies the vehicle's electrical architecture, deeply integrating various control modules into a central framework structure with a central control board at its core. This reduces costs and energy consumption, improves safety performance, and makes vehicle application more convenient.

Description

Technical Field

[0001] This invention relates to the field of automatic control, and more specifically to a domain controller, control method, and electric vehicle for electric vehicles. Background Technology

[0002] China's new energy commercial vehicle industry has been developing for over two decades since its inception in 2000, with the technology gradually maturing in the last decade. Throughout the development of electric vehicles, the power system mainly consists of the vehicle control architecture, battery system, drive system, and related accessories. Different architectures employ independent control modules, with some having dozens of controllers. These modules are connected via the CAN communication system. With the continuous emergence of new technologies, the number of ECUs in new energy vehicles is constantly increasing, making automotive electronic and electrical systems increasingly complex. This makes CAN network communication increasingly insufficient to meet the needs of vehicle communication; increased size and weight make system expansion more difficult, leading to greater energy waste; and the integration and verification of complex functions are also more challenging, resulting in more and more safety hazards in the control system.

[0003] Currently, some manufacturers have proposed integrated power system solutions for new energy electric vehicles. For example, Chinese patent CN112644293A proposes a power system controller that integrates motor control and other high-voltage accessory modules. While this effectively optimizes the structure of the power system in some areas, it only integrates a portion of the modules, and the integration solution needs further improvement. Chinese patent CN111572364A proposes a power domain control system for electric vehicles, which only integrates the electric vehicle's thermal management system into the power domain, improving energy utilization. However, it does not consider energy-saving optimization of the electric vehicle's main drive motor, resulting in limited energy-saving effects. Chinese patent CN113428093A proposes an automotive information security solution developed based on a power domain architecture. This patent only proposes increasing the efficiency of automotive information security development without providing a specific solution for the power domain architecture.

[0004] Therefore, existing technologies require a solution that can simplify the control module of electric vehicles.

[0005] The information disclosed in the background section above is only used to further understand the background of the present invention, and therefore may include information known to those skilled in the art that does not constitute prior art. Summary of the Invention

[0006] This invention relates to a domain controller, control method, and electric vehicle. The solutions provided by this invention address the following problems: reducing the number of ECU hardware components and lowering controller hardware costs; simplifying system topology, reducing space requirements, and improving system safety; and enabling multiple algorithms to work collaboratively, increasing efficiency and reducing energy consumption.

[0007] A first aspect of the present invention provides a domain controller for an electric vehicle, comprising a vehicle control module, an energy management module, and a motor control module, wherein the vehicle control module uses external sensors to sample in real time the opening information of the accelerator pedal and brake pedal and the motor speed information; the energy management module calculates the state of charge (SOC) value of the battery; and the motor control module calculates the motor torque output and energy feedback power based on the opening information, the motor speed information, and the battery SOC value.

[0008] According to one embodiment of the present invention, the vehicle control module, energy management module and motor control module are respectively integrated into three cores in a processor.

[0009] According to one embodiment of the present invention, the vehicle control module is further used to realize the power-on / off control of the electric vehicle, vehicle fault management, data calibration management, control strategy management, data storage, and low-level input and output; the energy management module is further used to realize the charging control of the electric vehicle and battery self-heating; the motor control module is further used to realize the calculation of acceleration and braking torque of the electric vehicle, acceleration and braking pedal analysis, field weakening control, motor vector algorithm, energy recovery, and torque safety control.

[0010] According to one embodiment of the present invention, the three cores of the processor are integrated in the central control board of the domain controller, which receives and sends signals from the electric vehicle for centralized integrated control.

[0011] According to one embodiment of the present invention, the calculation of motor torque output includes: implementing fuzzy torque compensation control based on a concave curve in the motor control module, wherein the fuzzy torque compensation control includes: using the electric vehicle's power pedal opening change rate, current vehicle speed, and the SOC of the power battery as the basis for torque compensation, and correcting the electric vehicle torque according to a preset rule; wherein the preset rule is: reducing the compensation value when the battery has a low SOC, and appropriately increasing the compensation value when the battery has a medium and high SOC, thereby correcting the base torque obtained through the concave reference torque diagram to improve the sensitivity of torque commands to driver operation.

[0012] According to one embodiment of the present invention, the actual power fed back to the battery is determined based on the motor energy feedback input power, the inverter loss power during energy feedback, and the battery energy consumption equation.

[0013] According to an embodiment of the present invention, the calculation of energy feedback power includes: implementing a braking energy feedback mechanism in the motor control module, the braking energy feedback mechanism including: when the brake opening is 0, the braking energy feedback is 0; when the brake pedal opening is small, the output follows the maximum feedback power torque line; and when the brake pedal opening is medium, the output follows the inverter capacity limit line. The maximum braking feedback power curve is obtained by taking the partial derivative of the feedback battery power with respect to the electromagnetic torque. The maximum feedback power torque line is based on the maximum braking feedback power curve according to an embodiment of the present invention. The power curve is a two-dimensional curve representing the motor speed and the energy feedback torque during braking. It includes: energy consumption braking zone I, braking energy feedback zone II, optimal braking energy feedback zone III, and inverter energy excess zone IV. In zone I, the motor speed is too slow to provide energy feedback, and mechanical braking is performed using a brake disc. In zone II, the motor braking provides the optimal braking torque, and the remainder is provided by mechanical braking. In zone III, the braking torque is entirely achieved by electric braking. In zone IV, electric braking has provided the maximum braking torque but still cannot meet the braking force of the electric vehicle, and the unmet portion is provided by mechanical braking.

[0014] Specifically, the maximum power torque line output of the braking energy feedback is obtained in the optimal braking energy feedback zone III.

[0015] According to one embodiment of the present invention, the system further includes a safety management module, in which a battery-motor weak short-circuit mechanism is implemented, the battery-motor weak short-circuit mechanism comprising:

[0016] When the ambient temperature is detected to be lower than the preset threshold, the maximum heating current and AC polarization voltage are calculated based on the battery material characteristics. The connection between the battery and the motor is short-circuited, and the inverter duty cycle is controlled to adjust either the short-circuit current or the voltage to reach the preset value. The motor speed is set to 0 through the motor control module to generate a stall current, thereby heating the battery. The current for heating the battery is updated in real time according to the current battery parameters.

[0017] According to one embodiment of the present invention, a fault diagnosis module based on application layer software is further included, the fault diagnosis module being used to realize the functions of unified power battery diagnosis, insulation diagnosis, vehicle diagnosis and motor control diagnosis.

[0018] According to one embodiment of the present invention, the fault diagnosis module classifies faults according to energy system, power system and vehicle accessories, and locates and distinguishes faults into different fault levels in order to take different handling measures; wherein, when the fault level is low, the fault diagnosis module informs the driver by reporting an error or issuing a slight alarm signal; when the fault level is high and accompanied by danger, the fault diagnosis module will limit the power of the whole vehicle or directly disconnect the high voltage contactor.

[0019] A second aspect of the invention provides an electric vehicle including the domain controller described above.

[0020] A third aspect of the present invention provides a control method for an electric vehicle, comprising: real-time sampling of the opening information of the accelerator pedal and brake pedal, and motor speed information; calculating the state of charge (SOC) value of the battery; calculating the motor torque output and energy feedback power based on the opening information, motor speed information, and battery SOC value; and controlling the electric vehicle based on the torque output and energy feedback power.

[0021] According to one embodiment of the present invention, the calculation of motor torque output includes: calculating motor torque output based on fuzzy torque compensation control using a concave curve, wherein the fuzzy torque compensation control includes: using the electric vehicle's power pedal opening change rate, current vehicle speed, and power battery SOC as the basis for torque compensation, and performing fuzzy domain division and fuzzification operations, and correcting the electric vehicle torque according to a preset rule; wherein the preset rule is: reducing the compensation value when the battery SOC is low, increasing the compensation value when the battery SOC is medium and high, and correcting the base torque obtained through the concave reference torque diagram to improve the sensitivity of torque commands to driver operation.

[0022] According to one embodiment of the present invention, the actual power fed back to the battery is determined based on the motor energy feedback input power, the inverter loss power during energy feedback, and the battery energy consumption equation.

[0023] According to an embodiment of the present invention, the calculation of energy feedback power includes: calculating the energy feedback power through a braking energy feedback mechanism, wherein the braking energy feedback mechanism includes: when the brake opening is 0, the braking energy feedback is 0; when the brake pedal opening is small, the output is based on the maximum feedback power torque line; and when the brake pedal opening is medium, the output is based on the inverter capacity limit line. The maximum braking feedback power curve is obtained by taking the partial derivative of the feedback battery power with respect to the electromagnetic torque, and the maximum feedback power torque line is based on the maximum braking feedback power curve.

[0024] According to one embodiment of the present invention, the maximum power curve of braking feedback is a two-dimensional curve of motor speed and energy feedback torque during braking, including: energy consumption braking zone I, braking energy feedback zone II, optimal braking energy feedback zone III, and inverter energy excess zone IV. In zone I, the motor speed is too slow to provide energy feedback, and mechanical braking is performed using a brake disc. In zone II, the motor braking provides the optimal braking torque, and the remainder is provided by mechanical braking. In zone III, the braking torque is entirely achieved by electric braking. In zone IV, the electric braking has provided the maximum braking torque but still cannot meet the braking force of the electric vehicle, and the unmet portion is provided by mechanical braking. The maximum power torque line output is obtained in the optimal braking energy feedback zone III.

[0025] According to one embodiment of the present invention, a battery-motor weak short-circuit mechanism is implemented in the safety management module of the electric vehicle. The battery-motor weak short-circuit mechanism includes: when the external temperature is detected to be lower than a preset threshold, calculating the current maximum heating current and AC polarization voltage based on the battery material characteristics, short-circuiting the connection between the battery and the motor, controlling the inverter duty cycle to adjust either the short-circuit current or the voltage to reach a preset value, setting the motor speed to 0 through the motor control module to generate a stall current, thereby heating the battery, and updating the current for heating the battery in real time according to the current battery parameters.

[0026] According to one embodiment of the present invention, fault diagnosis is implemented in the electric vehicle. The fault diagnosis classifies faults according to the energy system, power system, and vehicle accessories, and locates and distinguishes different fault levels to take different handling measures. When the fault level is low, the fault diagnosis module informs the driver by reporting an error or issuing a slight alarm signal. When the fault level is high and accompanied by danger, the fault diagnosis module will limit the power of the entire vehicle or directly disconnect the high-voltage contactor.

[0027] The present invention significantly simplifies the vehicle's electrical architecture compared to current distributed solutions, and deeply integrates various control modules into a central framework structure with a central control board at its core. Compared to traditional distributed control modules, the present invention offers the following advantages:

[0028] (1) Reduce cost and energy consumption: The solution of the present invention can reduce the number of ECU hardware by 30%, effectively save costs, save 50% of the controller installation space compared with the current solution, and improve the system response speed by more than 100 times with the multi-task central integrated software design, which facilitates refined energy-saving optimization.

[0029] (2) High safety and reliability: The controller replaces some of the traditional CAN communication with communication methods such as variable transmission inside the controller, reducing the CAN network resource occupation and reducing the hardware failure rate. The central control architecture facilitates centralized fault detection. The battery motor forms a self-heating circuit, increasing the safety of charging at low temperatures.

[0030] (3) Convenient for vehicle application: It greatly reduces the electrical architecture of the power system, and the vehicle assembly and debugging time can be shortened to 1 / 3 of the current time. It has strong portability, supports remote OTA upgrades, simplifies fault management strategies, accelerates development efficiency, and meets the needs of vehicle networking and intelligent data rapid communication and transmission. Attached Figure Description

[0031] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the following description of the embodiments will be simplified. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a diagram of the distributed electrical architecture of existing electric vehicles.

[0033] Figure 2 This is an integrated electrical architecture diagram of an electric vehicle according to an exemplary embodiment of the present invention.

[0034] Figure 3 This is a block diagram of a domain controller according to an exemplary embodiment of the present invention.

[0035] Figure 4 This is a graph showing the relationship between the concave reference curve torque load coefficient and the accelerator pedal according to an exemplary embodiment of the present invention.

[0036] Figure 5 This is a block diagram of fuzzy torque compensation control according to an exemplary embodiment of the present invention.

[0037] Figure 6 This is a reference torque diagram for the graded pedal opening of a commercial vehicle according to an exemplary embodiment of the present invention.

[0038] Figure 7 This is a schematic diagram of the mechanical and electric braking feedback of a bus according to an exemplary embodiment of the present invention.

[0039] Figure 8a and Figure 8b This is a comparison chart of the regenerative braking torque before and after optimization according to an exemplary embodiment of the present invention.

[0040] Figure 9 This is a schematic diagram of the maximum braking energy feedback curve according to an exemplary embodiment of the present invention.

[0041] Figure 10a and Figure 10b This is a comparison diagram of distributed and integrated electrical architecture control strategies according to an exemplary embodiment of the present invention.

[0042] Figure 11 This is a battery-motor weak short-circuit circuit diagram according to an exemplary embodiment of the present invention. Detailed Implementation

[0043] As used herein, the terms "first," "second," etc., can be used to describe elements in exemplary embodiments of the present invention. These terms are used only to distinguish one element from another, and the inherent features or order of the corresponding elements are not limited by the term. Unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in common dictionaries are to be interpreted as having the same meaning as in the context of the relevant technical field, and not as having an ideal or overly formal meaning, unless explicitly defined as having such a meaning in this invention.

[0044] Those skilled in the art will understand that the apparatus and methods of the present invention described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments, and the scope of the invention is defined only by the claims. Features illustrated or described in conjunction with an exemplary embodiment may be combined with features of other embodiments. Such modifications and variations are included within the scope of the invention.

[0045] In the following description, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, detailed descriptions of known functions or configurations are omitted to avoid unnecessarily obscuring the key technical aspects of the invention. Furthermore, throughout the description, the same reference numerals always refer to the same circuits, modules, or units, and for the sake of brevity, repeated descriptions of the same circuits, modules, or units are omitted.

[0046] Furthermore, it should be understood that one or more of the following methods or aspects can be performed by at least one control unit or controller. The terms "control unit," "controller," "control module," or "main control module" can refer to a hardware device including a memory and a processor. The memory or computer-readable storage medium is configured to store program instructions, and the processor is specifically configured to execute the program instructions to perform one or more processes, which will be further described below. Moreover, it should be understood that, as those skilled in the art will recognize, the following methods can be performed by including a processor in conjunction with one or more other components.

[0047] Given the numerous problems associated with distributed architectures, this invention provides an integrated electrical architecture and control method for new energy commercial vehicles. This method integrates the control modules of the vehicle control architecture, battery system, drive system, and related accessories, forming a novel integrated commercial vehicle electrical / electronic architecture. This solution integrates various sensors, central processing units, wiring harness topologies, electrical / electronic distribution systems, and hardware and software within the vehicle to achieve overall vehicle configuration and functionality, as well as the allocation of computing power, power, and energy. The power domain features a service-oriented electrical / electronic architecture, allowing developers to create efficient new functions that are easily integrated into the entire ecosystem. It can provide personalized services to each user, supporting over-the-air (OTA) updates, feature optimization, and flexible lifecycle management. This solution also incorporates battery self-heating technology, increasing safety at low temperatures. The integrated power domain control system can also achieve centralized and refined energy management through algorithm integration, making the vehicle more energy-efficient and expanding the energy recovery range.

[0048] Figure 1 This is a diagram of the distributed electrical architecture of existing electric vehicles. Figure 2 This is an integrated electrical architecture diagram of an electric vehicle according to an exemplary embodiment of the present invention.

[0049] According to one or more embodiments of the present invention, the power system of traditional new energy commercial vehicles typically adopts a distributed control method, such as... Figure 1 As shown, the BMS is integrated into the battery module, and the power distribution system distributes electrical energy to the drive module. This results in a complex structure, information redundancy, and is not conducive to upgrades and functional development. The pure electric commercial vehicle designed in this invention adopts a domain integration architecture, distributing the energy in the power battery to various power-consuming modules, such as... Figure 2 As shown, compared to traditional distributed electrical architecture, domain integrated architecture integrates various sensors, central processing units, wiring harness topologies, electronic and electrical distribution systems, and hardware and software in a vehicle, eliminating redundant designs, reducing costs, decreasing failure rates, and improving safety; it adopts a unified architecture system development approach, supports OTA updates, and accelerates development efficiency; through the integration of software algorithms, it achieves maximum utilization of computing power and energy, realizing centralized and refined energy management.

[0050] Figure 3 This is a block diagram of a domain controller according to an exemplary embodiment of the present invention.

[0051] if Figure 3As shown, the domain controller for electric vehicles includes a vehicle control module, an energy management module, and a motor control module. The vehicle control module uses external sensors to sample the opening information of the brake pedal and accelerator pedal and the motor speed information in real time; the energy management module calculates the battery's SOC value; and the motor control module calculates the motor torque output and energy feedback power based on the opening information, motor speed information, and battery SOC value.

[0052] According to one or more embodiments of the present invention, the solution of the present invention is a power domain integrated architecture obtained through overall hardware and software optimization. Hardware optimization involves developing a unified architecture system by integrating various sensors, central processing units, wiring harness topologies, electronic and electrical distribution systems, and hardware and software within the vehicle. This eliminates redundant design, reduces costs, lowers failure rates, and improves safety. The specific coordination relationship between the internally implemented algorithms and hardware is as follows: In the torque distribution algorithm, the vehicle control unit (or vehicle control module, vehicle controller) (VCU) in the power domain samples the accelerator pedal opening information and motor speed information in real time through external sensors. The motor control module (or motor control unit, or motor controller) (usually an MCU) reads the battery's SOC value from the energy management module (usually a battery management system, BMS in automobiles) through internal communication and calculates the torque using a fuzzy algorithm. The vehicle speed, brake and brake pedal opening and their rate of change in the input signals are collected by the VCU. The battery SOC is calculated by the energy management module in the battery pack. The motor control module calculates the motor torque output and energy feedback power, all through internal communication within the domain controller, increasing the algorithm's execution efficiency.

[0053] According to one or more embodiments of the present invention, the electric vehicle power domain controller designed in this invention eliminates the cumbersome communication network between the battery system, vehicle control system, and power control system in commonly used distributed architectures, simplifying the controlled objects to "vehicle control module, energy management module, and motor control module". The three-core CPU in the central control board performs unified control of vehicle control, energy management, and power flow (motor power output), integrating the vehicle control module, energy management module, and motor control module into three cores in the processor, which optimizes ECU hardware utilization. The central control board can be located in the domain controller. The vehicle control module includes power-on / off control, vehicle fault management, data calibration management, control strategy management, data storage, and low-level input and output; the energy management module includes charging control, battery SOC estimation, and battery self-heating; the motor control module includes acceleration and braking torque calculation, acceleration and braking pedal analysis module, field weakening control, motor vector algorithm, energy recovery, and torque safety module.

[0054] The power domain controller enables unified control of the main drive motor, oil pump motor, and air pump motor. It samples three-phase current via IGBT modules and drives the motors through PWM signals and H-bridges, responding to torque commands from the power domain controller. The central control board receives and sends signals, centrally managing the integrated control of the entire architecture. The central control board possesses powerful data processing capabilities. Various component systems within the vehicle module send signals to the central control board via CAN communication, which then performs centralized management and control. The central control board controls the on / off state of PDU relays and contactors, as well as power-on detection, through I / O channel switches. The BMU (Battery Management Unit, or BMS) collects signals such as individual battery cell voltage and temperature, as well as bus voltage and current, and sends commands to the central control board via CAN communication for real-time signal processing (e.g., SOC battery state estimation, equalization management, charge / discharge management, etc.). The central control board performs vehicle energy calculations, sends PWM signals, which are amplified by the main drive power drive module. Based on these driving commands, the central control board controls the motors to output specified torque and speed, achieving vehicle driving. The central control board sends a PWM signal, which is amplified and processed by the oil pump power drive module to drive the oil pump motor to run smoothly and realize the steering and holding force function of the electric vehicle; the central control board sends a PWM signal, which is amplified and processed by the air pump power drive module to drive the air pump motor to run smoothly and realize the braking, door closing and other functions of the electric vehicle.

[0055] According to one or more embodiments of the present invention, the solution of the present invention can implement deeply integrated and refined energy management and control.

[0056] In the distributed solution, the MCU, PDU, DC-DC converter, air pump, and oil pump are integrated into one unit. The power domain adds a VCU and BMS, and integrates the hardware and software optimizations described in this solution. Due to uneven ECU performance distribution and excessively high CAN bus load, the system response time is 100ms, which does not support real-time fine-grained energy management. The torque distribution and energy recovery algorithms used are ordinary linear schemes, which, although computationally less, do not consider fine-grained energy management, resulting in energy waste. In the power domain architecture, a 3-core CPU is used for vehicle control, coordinating power flow control and energy management. Internal variable transmission within the controller replaces some traditional CAN communication, achieving a system response time of less than 1ms. Therefore, based on the power domain architecture (which integrates the vehicle control module, battery management module, motor control module, and related accessories), this invention proposes a vehicle torque energy-saving distribution method and an optimal braking energy feedback control strategy for the motor, combined with battery SOC optimization to maximize energy utilization. The powertrain architecture integrates the vehicle control module, battery management module, motor control module, and related accessories.

[0057] According to one or more embodiments of the present invention, a high-energy-saving drive torque distribution design scheme is provided.

[0058] Figure 4 This is a graph showing the relationship between the concave reference curve torque load coefficient and the accelerator pedal according to an exemplary embodiment of the present invention. Figure 4 As shown, in the vehicle torque energy-saving distribution scheme, this scheme designs a "concave" baseline minimum torque curve MAP, where MAP represents the relationship between two or more physical quantities. Specifically, when the accelerator pedal is open at low to medium degrees, torque adjustment is slower and torque output is smaller. When the acceleration pedal opening is 100%, the torque output domain exhibits the same linear pattern, ensuring the vehicle's maximum power performance and avoiding additional energy loss due to frequent excessive acceleration and deceleration. However, this "concave" baseline torque curve pattern has the drawback of slow power response during rapid acceleration. To compensate for this drawback, this scheme proposes a fuzzy torque compensation control strategy based on the concave curve, such as... Figure 5 As shown.

[0059] Figure 5 This is a block diagram of fuzzy torque compensation control according to an exemplary embodiment of the present invention. Figure 5 In the diagram, ACC represents the brake opening degree; MAP represents the reference torque. Figure 4 The MAP diagram shows that the output torque is calculated by looking up a table based on the brake pedal opening. ΔT is the torque fuzzy compensation amount, used to compensate for the torque obtained from the table lookup. The torque constraint module is used to limit the torque output value from not exceeding the maximum value. The torque smoothing module makes the torque output amount transition smoothly and prevents torque jumps. The drive motor outputs torque according to the torque set value. The fuzzy torque compensation control reads the motor speed n (to calculate the vehicle speed), the battery SOC, and calculates the current system efficiency. It uses the fuzzy inference module in conjunction with the throttle opening change rate to calculate ΔT.

[0060] According to one or more embodiments of the present invention, the fuzzy torque compensation control algorithm has three input quantities, of which the throttle change rate is an external input quantity, the battery SOC, and the vehicle speed is an internal input quantity (hence the name system efficiency). The joint system efficiency module integrates the internal input quantities together, and the fuzzy membership function optimization module divides the internal input quantities into fuzzy domains.

[0061] According to one or more embodiments of the present invention, this scheme considers the throttle opening (ACC) change rate, current vehicle speed and battery SOC as one of the bases for torque compensation. The basic rule is to reduce the compensation value at low SOC and appropriately increase the compensation value at medium and high SOC to correct the base torque obtained from the concave reference torque map (MAP) and improve the sensitivity of torque command to driver operation.

[0062] According to one or more embodiments of the present invention, the parameters are first divided into fuzzy domains and fuzzified. The vehicle speed input range is defined as 0-100km / h, and the vehicle speed is divided into 5 domain intervals: very low (ZS), low (S), medium (M), high (B), and very high (ZB). The accelerator pedal opening change rate refers to the increment of the accelerator pedal opening within a certain time interval compared to the previous moment, and is defined in the range of 0-500. According to the rate of change from slow to fast, its linguistic variables are set to 5 intervals: no change (Z), slow change (S), medium change (M), relatively fast change (B), and fast change (ZB). The battery SOC linguistic is defined as low (S), medium (M), and high (B). Torque compensation is to add a target torque amount to the reference MAP, and the maximum compensation amount is defined as 300 N.m (Newton-meters), with a range of 0-300 N.m. According to no compensation to maximum compensation, it is defined as 5 intervals: zero (Z), small (S), medium (M), large (B), and very large (ZB).

[0063] Figure 6 This is a reference torque diagram for the graded pedal opening of a commercial vehicle according to an exemplary embodiment of the present invention. The fuzzy compensated torque surface under different SOCs during driving is shown below. Figure 6 As shown. The motor torque corresponding to different brake pedal openings at different vehicle speeds. Figure 6 The highest curve represents 100% brake pedal opening, and it gradually decreases downwards.

[0064] According to one or more embodiments of the present invention, a braking energy feedback model curve establishment and strategy are also provided.

[0065] Figure 7 This is a schematic diagram of the mechanical and electric braking feedback of a bus according to an exemplary embodiment of the present invention.

[0066] like Figure 7 As shown, new energy commercial vehicles generally adopt a parallel braking scheme of electrical and mechanical components. When braking, electric vehicles can utilize the mechanical braking of traditional fuel vehicles, or they can use back electromotive force to use the motor as a generator to convert mechanical energy into electrical energy. For example... Figure 7 As shown, the ECU acts as a processor, calculating the torque for regenerative braking by collecting brake pedal signals, battery SOC, and mechanical brake chamber pressure. The regenerated energy from the motor then charges the battery, with the remaining braking force provided by the mechanical brakes. Traditional new energy vehicles use a method where the regenerative torque increases linearly with the brake opening. This method does not consider an optimal braking regenerative model, resulting in low braking energy regeneration.

[0067] Figure 8a and Figure 8b This is a comparison chart of the regenerative braking torque before and after optimization according to an exemplary embodiment of the present invention.

[0068] exist Figure 8a and Figure 8b In this context, 'n' represents the motor speed, and 'Te' represents the energy feedback torque during braking. The unit of torque is Nm (Newton-meters). There are three coordinates: the brake pedal value is the brake pedal opening, 'n' is the motor speed, and 'Te' is the electric braking torque. Figure 8a When the rotational speed is constant, the electric braking torque increases linearly with the brake pedal opening, and the electric braking reaches its maximum when the brake pedal opening is at its maximum. Figure 8b When the engine speed is constant, as the brake pedal opening increases, electric braking is prioritized for maximum utilization. Therefore... Figure 8b This allows for maximum energy recovery.

[0069] According to one or more embodiments of the present invention, during braking energy regenerative braking, the energy regenerative input power of the motor is:

[0070]

[0071] In the above formula, the meanings of each parameter are as follows: P in : Motor energy feedback input power; u d Stator d-axis voltage; i d Stator d-axis current; u q : Stator q-axis voltage; i q Stator q-axis current; R a Stator winding phase resistance; ψ d : Stator d-axis flux linkage; ψ q : Stator q-axis flux linkage; ψ f : Permanent magnet flux linkage; ω: Rotor electric angular velocity; i qt : The derivative of the stator q-axis current iq with respect to time t; R i Iron loss resistor.

[0072] According to one or more embodiments of the present invention, the inverter losses are divided into conduction losses and switching losses. During energy feedback, the inverter losses are:

[0073]

[0074] In the above formula, the meanings of each parameter are as follows: P inv Inverter loss function; P c Three-phase inverter conduction loss; P sw Switching losses in a three-phase inverter; t d Dead time; V f : Voltage drop of the diode at zero current; t c : PWM cycle time; k on : Turn-on loss coefficient; f s Switching frequency; k off : Turn-off loss coefficient; Im Phase current peak value; R ak Diode resistance; R ds MOSFET resistor.

[0075] According to one or more embodiments of the present invention, the battery model can be analyzed using an equivalent RC circuit, and the battery energy consumption equation is as follows:

[0076] P bR =(R s +R t )i b 2

[0077] In the above formula, the meanings of each parameter are as follows: P bR Battery energy loss; R s Battery internal resistance; R t : The resistor in the external RC network of the battery; i b Battery output current.

[0078] According to one or more embodiments of the present invention, the actual power fed back to the battery during energy feedback is obtained from the equations of the motor, inverter, and battery as follows:

[0079] P bat (ωT e ) = P in (ωT e )-P inv (ωT e )±P bR (ωT e )

[0080] In the above formula, the meanings of each parameter are as follows: P bat : Actual power fed back to the battery; ω: Rotor electrical angular velocity; T e Electromagnetic torque.

[0081] According to one or more embodiments of the present invention, the braking energy feedback model curve establishment and strategy are based on the optimal feedback model and designed according to the optimal model curve. When the brake opening is 0, the braking energy feedback is 0. When the brake pedal is light, the output follows the maximum feedback power torque line. After the brake pedal is moderate, the output follows the inverter capacity limit line. Specific strategies and feedback torque comparisons are provided. Figure 9 As shown.

[0082] Feedback battery power P bat For electromagnetic torque T e Taking the partial derivative yields the maximum power feedback curve for braking regenerative braking (see...). Figure 9The maximum braking power curve (as shown in the curve) is a two-dimensional curve of motor speed and electric braking torque, including: energy consumption braking zone I, braking energy feedback zone II, optimal braking energy feedback zone III, and zone IV. Zone I, to the left of the torque curve, is the energy consumption braking zone. Because the motor speed is too slow to provide energy feedback, mechanical braking is performed using a brake disc. Zone II, to the right of the energy feedback curve, is the braking energy feedback zone (non-optimal energy feedback). Electric braking only provides the optimal braking torque, with the remainder provided by mechanical braking. Zone III is the optimal braking energy feedback zone (considering motor and inverter capacity), where it is entirely achieved by electric braking. Zone IV is the inverter energy excess zone. In Zone IV, electric braking has provided the maximum braking torque but still cannot meet the braking force requirements; the remainder is provided by mechanical braking.

[0083] Figure 10a and Figure 10b This is a comparison diagram of distributed and integrated electrical architecture control strategies according to an exemplary embodiment of the present invention.

[0084] According to one or more embodiments of the present invention, Figure 10a Traditional distributed electrical architectures are quite complex. For the two control strategies in this solution, vehicle speed, brake and accelerator pedal openings and their rates of change in the input signals are acquired by the VCU; battery SOC is calculated by the BMS in the battery pack; and the motor control module (MCU) calculates the motor torque output and energy feedback power. Signals are easily repeated in multiple subnets, increasing the vehicle bus load rate, leading to slower system response, higher controller power consumption, and a higher failure rate. Figure 10b In this solution, the VCU, BMS, and MCU are centrally controlled in a single tri-core DSP within the integrated electrical architecture. Variable transmission is used within the controller to replace some CAN communication, significantly reducing the bus load and meeting the vehicle's intelligent data communication and transmission requirements. Figure 9 Right General Figure 9 The VCU, BMS, and MCU on the left are integrated into the domain controller, which is centrally controlled by a three-core DSP (or a CPU with three integrated cores), reducing system redundancy and making it easier to develop refined energy management control algorithms.

[0085] According to one or more embodiments of the present invention, a safety management scheme for an integrated electronic and electrical architecture is also provided. When the ambient temperature is too low, the charging speed of lithium batteries is slow, which easily leads to lithium plating on the negative electrode, seriously affecting battery life and even causing safety hazards. Therefore, the present invention proposes a battery self-heating scheme. Traditional schemes generally use external heating methods, such as external thermal convection heating and external thermal contact heating, which require the addition of additional heating modules, resulting in high costs, poor internal heating effect of the battery, and low energy utilization. Based on this, the present invention proposes a battery-motor weak short-circuit self-heating scheme, the circuit of which is as follows: Figure 11 As shown.

[0086] Figure 11 This is a battery-motor weak short-circuit circuit diagram according to an exemplary embodiment of the present invention, such as... Figure 11 As shown, rapid AC high-frequency heating of the battery at low temperatures requires high polarization voltage and high heating current. However, as the battery temperature increases, the internal resistance decreases, and the heating efficiency declines. Therefore, as the battery internal resistance decreases, the current needs to be increased. Thus, the current calculation formula is:

[0087]

[0088] Among them, Z Re Z Im These represent the real and imaginary impedances of the battery, respectively. Since the polarization voltage cannot be measured in real time, it needs to be determined based on changes in battery SOC, open-circuit voltage, and battery terminal voltage. Then, the heating current is calculated based on the battery parameters. Therefore, ensuring a constant polarization voltage requires pre-calculating the applicable heating current based on the battery model. Under sinusoidal AC conditions, the battery heat generation is:

[0089]

[0090] The battery-motor weak short-circuit self-heating scheme of this invention is as follows: When the external temperature is detected to be below a threshold, the maximum heating current and AC polarization voltage are calculated based on the battery material characteristics. The connection between the battery and the motor is short-circuited, and the inverter duty cycle is controlled to adjust either the short-circuit current or voltage to a preset value. The motor control module sets the motor speed to 0 to generate a stall current, thereby heating the battery. The heating current is updated in real time according to the current battery parameters. The principle of the battery-motor weak short circuit is to use the battery-motor short-circuit current and the battery's internal resistance to heat the battery. The battery and motor are connected through an inverter, which acts as a switch. Adjusting the frequency and time of the switch's on and off states enables a weak short circuit of the battery, thus allowing heating using the battery's internal resistance. The stall current means that if current flows through the motor, it should rotate. However, it is difficult to heat the battery using its internal resistance because much of the current is used to control the motor's rotation. If the motor speed is controlled to 0, the motor will not rotate, equivalent to a wire connected in a circuit, where electrical energy is completely converted into heat energy.

[0091] According to one or more embodiments of the present invention, the domain controller of the present invention further includes a fault diagnosis module, which mainly relies on application layer software implementation. Based on the V-shaped development process, model-based development, and automatic code generation, it realizes the functions of unified power battery diagnosis, insulation diagnosis, vehicle diagnosis, and motor control diagnosis. In the domain controller, faults are classified according to energy system, power system, and vehicle accessories, and distinguished into different fault levels. Then, the fault is located, and finally, different handling measures are taken. When the fault level is low, the system informs the driver by reporting an error or issuing a minor alarm signal. When the fault level is high or even accompanied by danger, the system will adopt a control strategy of limiting the power of the entire vehicle or directly disconnecting the high-voltage contactor. Traditional distributed fault handling requires information transmission between different modules, which can easily lead to repeated signal transmission and increase the burden on CAN network communication. This solution simplifies the fault information transmission network based on the power domain architecture. By classifying and categorizing faults, it reduces fault redundancy, improves the development and debugging efficiency of developers, and has better portability. The fault diagnosis scheme of this invention develops a fault management strategy based on the integrated domain power architecture, realizing the functions of unified power battery diagnosis, insulation diagnosis, vehicle diagnosis and motor control diagnosis, and distinguishing different fault levels and taking different measures accordingly.

[0092] According to one or more embodiments of the present invention, the solution of the present invention can be matched to various vehicle types, such as logistics vehicles, and the electric vehicle of the present invention includes the above-mentioned domain controller.

[0093] According to one or more embodiments of the present invention, the present invention also provides a control method for an electric vehicle, comprising: sampling in real time the opening information of the accelerator pedal and the brake pedal and the motor speed information; calculating the SOC value of the battery; calculating the motor torque output and energy feedback power based on the opening information, the motor speed information and the SOC value of the battery, and controlling the electric vehicle based on the torque output and energy feedback power.

[0094] According to one or more embodiments of the present invention, the calculation of motor torque output includes: calculating motor torque output based on fuzzy torque compensation control using a concave curve, wherein the fuzzy torque compensation control includes: using the electric vehicle's power pedal opening change rate, current vehicle speed, and SOC of the power battery as the basis for torque compensation, and performing fuzzy domain division and fuzzification operations, and correcting the electric vehicle torque according to a preset rule; wherein the preset rule is: reducing the compensation value when the battery's SOC is low, increasing the compensation value when the battery's SOC is medium and high, and correcting the base torque obtained through the concave reference torque diagram to improve the sensitivity of torque commands to driver operation.

[0095] According to one or more embodiments of the present invention, the actual power fed back to the battery is determined based on the motor energy feedback input power, the inverter loss power during energy feedback, and the battery energy consumption equation.

[0096] According to one or more embodiments of the present invention, the calculation of energy feedback power includes: calculating the energy feedback power through a braking energy feedback mechanism, wherein the braking energy feedback mechanism includes: when the brake opening is 0, the braking energy feedback is 0; when the brake pedal opening is small, the output is based on the maximum feedback power torque line; and when the brake pedal opening is medium, the output is based on the inverter capacity limit line. The maximum braking feedback power curve is obtained by taking the partial derivative of the feedback battery power with respect to the electromagnetic torque, and the maximum feedback power torque line is based on the maximum braking feedback power curve.

[0097] According to one or more embodiments of the present invention, the maximum power curve of braking feedback is a two-dimensional curve of motor speed and energy feedback torque during braking, including: energy consumption braking zone I, braking energy feedback zone II, optimal braking energy feedback zone III, and inverter energy excess zone IV. In zone I, the motor speed is too slow to provide energy feedback, and mechanical braking is performed using a brake disc. In zone II, the motor braking provides the optimal braking torque, and the remainder is provided by mechanical braking. In zone III, the braking torque is entirely achieved by electric braking. In zone IV, the electric braking has provided the maximum braking torque but still cannot meet the braking force of the electric vehicle, and the unmet portion is provided by mechanical braking. The maximum power torque line output is obtained in the optimal braking energy feedback zone III.

[0098] According to one or more embodiments of the present invention, a battery-motor weak short-circuit mechanism is implemented in the safety management module of the electric vehicle. The battery-motor weak short-circuit mechanism includes: when the external temperature is detected to be lower than a preset threshold, calculating the current maximum heating current and AC polarization voltage based on the battery material characteristics, short-circuiting the connection between the battery and the motor, controlling the inverter duty cycle to adjust either the short-circuit current or the voltage to reach a preset value, setting the motor speed to 0 through the motor control module to generate a stall current, thereby heating the battery, and updating the current for heating the battery in real time according to the current battery parameters.

[0099] According to one or more embodiments of the present invention, fault diagnosis is implemented in the electric vehicle. The fault diagnosis classifies faults according to the energy system, power system, and vehicle accessories, and locates and distinguishes the faults into different fault levels to take different handling measures. When the fault level is low, the fault diagnosis module informs the driver by reporting an error or issuing a slight alarm signal. When the fault level is high and accompanied by danger, the fault diagnosis module will limit the power of the entire vehicle or directly disconnect the high-voltage contactor.

[0100] According to one or more embodiments of the present invention, the hardware improvement of the present invention is not only the integration of three-core control, but also the integration of various sensors, central processing units, wiring harness topologies, electronic and electrical distribution systems and hardware and software in the vehicle into a domain integrated architecture, eliminating redundant design, reducing costs, reducing failure rates, improving safety, and adopting a unified architecture system development to accelerate development efficiency; the inventive points of the software of the present invention include the establishment of high energy-saving torque distribution and braking energy feedback model curves and strategy schemes.

[0101] According to one or more embodiments of the present invention, the present invention adopts a domain controller to integrate the control module of the vehicle control architecture, battery system, drive system and related accessories, thereby reducing CAN network resource occupation, improving information transmission efficiency, increasing security, reducing the number of ECU hardware and installation space, and reducing hardware costs.

[0102] According to one or more embodiments of the present invention, the present invention deeply integrates vehicle control, drive control and battery energy management, and on this basis develops a system intelligent energy-saving control method to achieve optimal torque energy-saving distribution, optimal braking energy feedback and coordinated operation with battery SOC, thereby reducing the energy consumption of electric vehicles and further improving the vehicle's driving range.

[0103] According to one or more embodiments of the present invention, the present invention employs battery-motor weak short-circuit self-heating technology to prevent excessively low temperatures from affecting battery performance, increase vehicle safety in low temperatures, and uses algorithm optimization to reduce battery self-heating energy consumption and increase heating efficiency.

[0104] According to one or more embodiments of the present invention, the present invention proposes a novel fault diagnosis strategy based on the power domain architecture, realizing hierarchical and classified processing of power battery diagnosis, vehicle diagnosis, insulation diagnosis and motor control diagnosis, reducing the redundancy of fault processing and improving vehicle safety.

[0105] According to one or more embodiments of the present invention, the control logic of the present invention can implement the processing of the processes in the system described above using encoded instructions (e.g., computer and / or machine-readable instructions) stored on a non-transitory computer and / or machine-readable medium (e.g., hard disk drive, flash memory, read-only memory, optical disk, digital multifunction disk, cache, random access memory, and / or any other storage device or storage disk), storing information for any time period (e.g., extended time periods, permanent, transient instances, temporary caches, and / or information caches) in the non-transitory computer and / or machine-readable medium. As used herein, the term "non-transitory computer-readable medium" is explicitly defined to include any type of computer-readable storage device and / or storage disk, excluding propagated signals and transmission media.

[0106] According to one or more embodiments of the present invention, the logic in the system of the present invention can be implemented using control circuitry (control logic, main control system, or control module), which may include one or more processors and may also internally include non-transitory computer-readable media. Specifically, the main control system or control module may include a microcontroller (MCU). The processor used to implement the processing of the logic in the system of the present invention may be, for example, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and special-purpose processors (e.g., graphics processors, application processors, etc.). The processor may be coupled thereto and / or may include memory / storage devices and may be configured to execute instructions stored in the memory / storage devices to implement various applications and / or operating systems running on the controller in the present invention.

[0107] The accompanying drawings and detailed description of the invention, cited above as examples, serve to explain the invention but do not limit its meaning or scope as described in the claims. Therefore, those skilled in the art can readily make modifications from the above description. Furthermore, those skilled in the art can remove some of the components described herein without degrading performance, or add other components to improve performance. Additionally, those skilled in the art can change the order of steps in the method described herein depending on the process or equipment environment. Therefore, the scope of the invention should not be determined by the embodiments described above, but rather by the claims and their equivalents.

[0108] Although the invention has been described in conjunction with embodiments now considered to be achievable, it should be understood that the invention is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent configurations included within the spirit and scope of the appended claims.

Claims

1. A domain controller for an electric vehicle, comprising a vehicle control module, an energy management module and a motor control module, wherein, the vehicle control module samples in real time opening degree information of an accelerator pedal and a brake pedal and motor speed information from external sensors; the energy management module calculates a SOC value of a battery; and the motor control module calculates motor torque output and energy feedback power according to the opening degree information, the motor speed information and the SOC value of the battery.

2. The domain controller of claim 1, wherein, The vehicle control module, the energy management module and the motor control module are integrated as three cores in a processor.

3. The domain controller according to claim 1, wherein, the vehicle control module is further configured to implement power-on and power-off control, vehicle fault management, data calibration management, control strategy management, data storage and bottom input and output of the electric vehicle; the energy management module is further configured to implement charging control and battery self-heating of the electric vehicle; the motor control module is further configured to implement acceleration and braking torque calculation, acceleration and braking pedal analysis, field weakening control, motor vector algorithm, energy recovery and torque safety control of the electric vehicle.

4. The domain controller according to claim 2, wherein the three cores in the processor are integrated in a central control board of the domain controller, the central control board receives and sends signals of the electric vehicle and performs integrated control.

5. The domain controller of claim 1, wherein, The calculation of the motor torque output comprises: implementing fuzzy torque compensation control based on a concave curve in the motor control module, the fuzzy torque compensation control comprising: taking the power pedal opening degree change rate, the current vehicle speed and the SOC of the power battery of the electric vehicle as torque compensation basis, and performing fuzzy domain division and fuzzy operation, and correcting the torque of the electric vehicle according to a preset rule; wherein the preset rule is to decrease the compensation value when the SOC of the battery is low, and to increase the compensation value when the SOC of the battery is medium and high, and to correct the basic torque obtained through the concave reference torque map to improve the sensitivity of the torque instruction to the driver's operation.

6. The domain controller of claim 1, wherein, The actual feedback power to the battery is determined according to the motor energy feedback input power, the loss power of the inverter during energy feedback and the energy consumption equation of the battery.

7. The domain controller of claim 1, wherein, The calculation of the energy feedback power comprises: implementing a brake energy feedback mechanism in the motor control module, the brake energy feedback mechanism comprising: when the brake opening degree is 0, the brake energy feedback is 0, when the brake pedal opening degree is small, the maximum power torque line is output, and when the brake pedal opening degree is medium, the inverter capacity limit line is output, wherein the brake feedback maximum power curve is obtained by taking the partial derivative of the electromagnetic torque with respect to the feedback battery power, and the feedback maximum power torque line is based on the brake feedback maximum power curve.

8. The field controller of claim 7, the brake regenerative maximum power curve is a two-dimensional curve of motor speed and energy regenerative torque at brake, wherein comprises: The energy consumption brake area I, the brake energy feedback area II, the brake energy feedback optimal area III and the inverter energy excess area IV, wherein, in area I, the motor speed is too slow to perform energy feedback, and a brake disc is used for mechanical braking; in area II, the motor brake provides optimal braking torque, and the rest is provided by mechanical braking; in area III, the braking torque is entirely realized by electric braking. In zone IV, the electric brake has provided the maximum braking torque but still cannot meet the braking force of the electric vehicle, and the unmet part is provided by the mechanical brake; Wherein, the maximum power torque line output is obtained in the optimal braking energy feedback zone III.

9. The domain controller of claim 1, wherein, Further comprising a safety management module, in which a battery-motor weak short circuit mechanism is implemented, the battery-motor weak short circuit mechanism comprising: When the external temperature is detected to be lower than a preset threshold, the current maximum heating current and alternating polarization voltage are calculated based on the battery material characteristics, the connection between the battery and the motor is short-circuited, the duty cycle of the inverter is controlled to adjust the short-circuit current or voltage to a preset value, the motor speed is set to 0 by the motor control module to generate a locked-rotor current, thereby heating the battery, and the current current for heating the battery is updated in real time according to the current parameters of the battery.

10. The domain controller of claim 1, further comprising a fault diagnosis module implemented based on application layer software, the fault diagnosis module being configured to implement functions of unified power battery diagnosis, insulation diagnosis, vehicle diagnosis, and motor control diagnosis.

11. The domain controller of claim 10, the fault diagnosis module being configured to classify faults according to energy system, power system, and vehicle accessories, and to locate and distinguish the faults into different fault levels to take different processing measures; wherein, When the fault level is low, the fault diagnosis module informs the driver by means of error reporting or sending a slight alarm signal, and when the fault level is high and dangerous, the fault diagnosis module takes measures of limiting the power of the vehicle or directly disconnecting the high-voltage contactor.

12. An electric vehicle comprising the domain controller of any one of claims 1-11.

13. A control method of an electric vehicle, comprising: sampling opening degree information of an accelerator pedal and a brake pedal and motor speed information in real time; calculating a SOC value of a battery; calculating motor torque output and energy feedback power according to the opening degree information, the motor speed information, and the SOC value of the battery, and controlling the electric vehicle according to the torque output and the energy feedback power.

14. The method of claim 13, the calculating motor torque output comprising: calculating the motor torque output based on fuzzy torque compensation control of a concave curve, the fuzzy torque compensation control comprising: taking the power pedal opening degree change rate of the electric vehicle, the current vehicle speed, and the SOC of the power battery as torque compensation basis, and performing fuzzy domain division and fuzzy operation, and correcting the torque of the electric vehicle according to a preset rule; wherein, the preset rule is to decrease the compensation value when the SOC of the battery is low, and to increase the compensation value when the SOC of the battery is medium and high, and to correct the basic torque obtained by the concave reference torque map to improve the sensitivity of the torque instruction to the driver's operation.

15. The method of claim 13, wherein, determining the actual feedback power to the battery according to the motor energy feedback input power, the inverter loss power during energy feedback, and the energy consumption equation of the battery.

16. The method of claim 13, wherein calculating the energy feedback power comprises: The calculation of the energy feedback power is realized by a braking energy feedback mechanism, which includes: when the brake opening degree is 0, the braking energy feedback is 0; when the brake pedal opening degree is small, the feedback maximum power torque line is outputted; when the brake pedal opening degree is medium, the inverter capacity limit line is outputted all the time, wherein the braking feedback maximum power curve is obtained by taking the partial derivative of the electromagnetic torque to the feedback battery power, and the feedback maximum power torque line is based on the braking feedback maximum power curve.

17. The method of claim 16, wherein the brake regenerative maximum power curve is a two-dimensional curve of motor speed and energy regenerative torque, wherein includes: The energy consumption braking area I, the braking energy feedback area II, the braking energy feedback optimal area III and the inverter energy excess area IV, wherein, In area I, the motor speed is too slow to feedback energy, and the mechanical brake is used for mechanical braking; In area II, the motor brake provides optimal braking torque, and the rest is provided by mechanical braking; In area III, the braking torque is all realized by electric braking; In area IV, the electric braking has provided the maximum braking torque but still cannot meet the braking force of the electric vehicle, and the unmet part is provided by mechanical braking; The feedback maximum power torque line output is obtained in the braking energy feedback optimal area III.

18. The method of claim 13, realizing a battery-motor weak short circuit mechanism in the safety management module of the electric vehicle, which includes: When the external temperature is detected to be lower than a preset threshold, the current maximum heating current and the alternating polarization voltage are calculated based on the battery material characteristics, the connection between the battery and the motor is short-circuited, the inverter duty cycle is controlled to adjust the short-circuit current or voltage to a preset value, the motor speed is set to 0 by the motor control module to generate a locked-rotor current, thereby heating the battery, and the current heating current of the battery is updated in real time according to the current parameters of the battery.

19. The method of claim 13, wherein, A fault diagnosis is realized in the electric vehicle, which classifies faults according to the energy system, the power system and the vehicle accessories, locates and distinguishes the faults into different fault levels, and takes different processing measures; wherein, When the fault level is low, the fault diagnosis module informs the driver by error reporting or sending a slight alarm signal, and when the fault level is high and accompanied by danger, the fault diagnosis module will take measures to limit the power of the whole vehicle or directly disconnect the high-voltage contactor.

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