A method and device for overheat protection of an electric power steering system

Abstract

The application discloses an electric power steering system overheat protection method, device, equipment and storage medium, wherein the method comprises the following steps: acquiring the current temperature of a control unit; judging whether the current temperature of the control unit exceeds the allowable temperature of the control unit; acquiring the input current of a motor, the running time of an electric power steering system and the number of overheat protection triggers; estimating the current temperature of the motor according to the input current of the motor, the running time and the number of overheat protection triggers; judging whether the current temperature of the motor exceeds the allowable temperature of the motor; when the current temperature of the control unit exceeds the allowable temperature of the control unit and / or the current temperature of the motor exceeds the allowable temperature of the motor, triggering overheat protection and updating the number of overheat protection triggers. The application can solve the problem that the overheat protection function of the electric power steering system is not started in time, and reduce the risk of burning the electric control components.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, specifically to the electronic control of an electric power steering system, and more particularly to a method and device for overheat protection of an electric power steering system. Background Technology

[0002] Since the beginning of the 21st century, the pace of vehicle electrification and intelligentization has been rapid. As the most important safety component of the car chassis, the steering system has also begun to widely use electric power steering (EPS) systems, which abandon the previous pure mechanical steering system and hydraulic steering system and use electric motor torque to provide assistance.

[0003] In the current wave of electric vehicles, the increased vehicle weight due to the power battery necessitates a larger motor for the electric power steering system to drive the vehicle. However, high-torque motors require high current, which generates more heat and can burn out the motor and electronic control unit (ECU). This poses a severe challenge to the heat resistance and safety performance of the EPS's electronic control components (ECU and motor). Therefore, overheat protection is needed to protect the electronic control components and prevent them from burning out due to excessive temperature, thus avoiding loss of power steering and threatening driver safety.

[0004] The overheat protection function of the electric power steering system is divided into two parts: ECU overheat protection and motor overheat protection. ECU overheat protection is achieved by installing a temperature sensor on the ECU circuit board. When the temperature detected by the sensor reaches the upper limit of the allowable temperature of the ECU components, the current output is reduced, thereby reducing heat generation and achieving a cooling effect. Motor overheat protection is achieved by adding a current sensor to the ECU circuit board to monitor the current flowing to the motor. Simultaneously, a thermodynamic model of the motor is established, and the motor temperature is estimated based on the current. When the motor temperature reaches the upper limit of the allowable temperature of the motor, the current output is reduced, achieving a cooling effect.

[0005] When estimating the current temperature of a motor using current, existing technologies, based on current sensors and fixed thermodynamic models, produce inaccurate calculations that risk excessive deviation and motor burnout. Furthermore, prolonged use in the complex environment of the vehicle (electromagnetic interference, humidity, atmospheric pressure) causes changes in the characteristics of the ECU and motor. Using the allowable temperature (constant) of the ECU and motor as a safety threshold to trigger overheat protection throughout their entire lifespan is unreasonable. If the allowable temperature of the electronic control components decreases during their lifespan, and overheat protection is not triggered, the ECU and motor may already be unable to withstand the current temperature and burn out. Summary of the Invention

[0006] This invention addresses the problem of inaccurate motor temperature estimation and the inability to update the current allowable temperatures of the motor and ECU in real time in existing technologies, which leads to untimely activation of the overheat protection function.

[0007] Therefore, the first aspect of the present invention proposes a method for overheat protection of an electric power steering system, comprising:

[0008] Get the current temperature of the ECU;

[0009] Determine whether the current temperature of the ECU exceeds the allowable temperature of the ECU;

[0010] Obtain the motor input current, the operating time of the electric power steering system, and the number of overheat protection triggers;

[0011] Estimate the current temperature of the motor based on the motor input current, the running time, and the number of times the overheat protection is triggered.

[0012] Determine whether the current temperature of the motor exceeds the allowable temperature of the motor;

[0013] When the current temperature of the ECU exceeds the allowable temperature of the ECU, and / or when the current temperature of the motor exceeds the allowable temperature of the motor, overheat protection is triggered and the number of overheat protection triggers is updated.

[0014] Further, estimating the current motor temperature based on the motor input current, the running time, and the number of overheat protection triggers includes:

[0015] The current temperature of the motor is estimated based on the motor input current to obtain an estimated motor temperature value.

[0016] The first temperature gain value corresponding to the running time is determined according to the first correspondence relationship; wherein, the first correspondence relationship is the correspondence between the running time and the first temperature gain value;

[0017] The second temperature gain value corresponding to the number of overheat protection triggers is determined according to the second correspondence; wherein, the second correspondence is the correspondence between the number of overheat protection triggers and the second temperature gain value;

[0018] The current temperature of the motor is obtained based on the estimated motor temperature, the first temperature gain value, and the second temperature gain value.

[0019] Further, before estimating the current temperature of the motor based on the motor input current, the process includes:

[0020] Obtain a pre-established correspondence curve; wherein the correspondence curve is used to describe the relationship between the current temperature of the motor, the estimated value of the motor temperature, the number of times the overheat protection is triggered, and the running time;

[0021] The current temperature of the motor and the estimated temperature of the motor corresponding to the running time are determined based on the corresponding relationship curve.

[0022] Based on the current temperature of the motor corresponding to the running time and the estimated value of the motor temperature, the first temperature gain value corresponding to the running time is calculated to obtain the first correspondence;

[0023] The current motor temperature and the estimated motor temperature corresponding to the number of times the overheat protection is triggered are determined based on the corresponding relationship curve.

[0024] Based on the current motor temperature and the estimated motor temperature corresponding to the number of overheat protection triggers, the second temperature gain value corresponding to the number of overheat protection triggers is calculated, thus obtaining the second correspondence.

[0025] Furthermore, after triggering the overheat protection and updating the overheat protection trigger count, the method further includes:

[0026] Obtain the square of the equivalent current per unit time when the ECU last triggered overheat protection;

[0027] Obtain the square of the equivalent current per unit time when the ECU triggers overheat protection;

[0028] The first ratio is calculated as the ratio of the square of the equivalent current per unit time when the ECU triggers overheat protection this time to the square of the equivalent current per unit time when the ECU triggers overheat protection last time.

[0029] Determine whether the first ratio is greater than or equal to a preset threshold;

[0030] If so, update the ECU allowable temperature according to the ratio between the ECU allowable temperature and the first ratio, and use the updated ECU allowable temperature as the ECU allowable temperature;

[0031] If not, maintain the allowable temperature of the ECU unchanged.

[0032] Furthermore, before obtaining the square of the equivalent current per unit time when the ECU triggers overheat protection, the following steps are included:

[0033] The start time of the allowable temperature change of the ECU is obtained as the first start time;

[0034] Determine whether the running time is greater than or equal to the first start time;

[0035] If so, proceed to the step of obtaining the square of the equivalent current per unit time when the ECU triggers overheat protection.

[0036] Furthermore, after triggering the overheat protection and updating the overheat protection trigger count, the method further includes:

[0037] Get the square of the equivalent current per unit time when the motor last triggered overheat protection;

[0038] Obtain the square of the equivalent current per unit time when the motor triggers overheat protection;

[0039] The second ratio is calculated as the ratio of the square of the equivalent current per unit time when the motor triggers overheat protection this time to the square of the equivalent current per unit time when the motor triggers overheat protection last time.

[0040] Determine whether the second ratio is greater than or equal to a preset threshold;

[0041] If so, update the allowable motor temperature according to the allowable motor temperature and the second ratio, and use the updated allowable motor temperature as the allowable motor temperature;

[0042] If not, keep the allowable temperature of the motor constant.

[0043] Furthermore, before obtaining the square of the equivalent current per unit time when the motor triggers overheat protection as the second entry value, the following steps are included:

[0044] The start time of the allowable temperature change of the motor is obtained as the second start time;

[0045] Determine whether the running time is greater than or equal to the second start time;

[0046] If so, proceed to the step of obtaining the square of the equivalent current per unit time when the motor triggers overheat protection.

[0047] A second aspect of the present invention provides an overheat protection device for an electric power steering system, comprising:

[0048] ECU temperature acquisition module, used to acquire the current temperature of the ECU;

[0049] The first trigger judgment module is used to determine whether the current temperature of the ECU exceeds the allowable temperature of the ECU;

[0050] The data acquisition module is used to acquire the motor input current, the running time of the electric power steering system, and the number of overheat protection triggers;

[0051] The motor temperature estimation module is used to estimate the current motor temperature based on the motor input current, the running time, and the number of overheat protection triggers.

[0052] The second trigger judgment module is used to determine whether the current temperature of the motor exceeds the allowable temperature of the motor.

[0053] An overheat protection module is used to trigger overheat protection and update the overheat protection trigger count when the current temperature of the ECU exceeds the allowable temperature of the ECU, and / or the current temperature of the motor exceeds the allowable temperature of the motor.

[0054] A third aspect of the present invention provides an electronic device comprising a processor and a memory, wherein the memory stores at least one instruction, at least one program, a code set, or an instruction set, wherein the at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by the processor to implement the overheat protection method for the electric power steering system proposed in the first aspect of the present invention.

[0055] A fourth aspect of the present invention provides a computer-readable storage medium storing at least one instruction, at least one program, a code set, or an instruction set, wherein the at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by a processor to implement the overheat protection method for an electric power steering system proposed in the first aspect of the present invention.

[0056] The implementation of this invention has the following beneficial effects:

[0057] The electric power steering system overheat protection method, device, equipment and storage medium provided by the present invention can solve the problem of the electric power steering system overheat protection function not activating in time, reduce the risk of electronic control components being burned out, further improve the safety of the electric power steering system and protect the driver's safety.

[0058] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0059] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0060] Figure 1 This is a schematic diagram of the overheat protection principle of the electric power steering system provided in an embodiment of the present invention;

[0061] Figure 2 This is a flowchart of the overheat protection method for an electric power steering system provided in an embodiment of the present invention;

[0062] Figure 3 This is a flowchart of step S140 provided in an embodiment of the present invention;

[0063] Figure 4 This is a flowchart of the allowable temperature update for the ECU provided in an embodiment of the present invention;

[0064] Figure 5 This is a flowchart of updating the allowable temperature of the motor provided in an embodiment of the present invention;

[0065] Figure 6 This is a structural block diagram of the overheat protection device for the electric power steering system provided in an embodiment of the present invention. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0067] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or server that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0068] This specification provides the operational steps of the methods described in the embodiments or flowcharts, but more or fewer operational steps may be included based on conventional or non-inventive labor. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only execution order. In actual system or server products, the methods shown in the embodiments or drawings can be executed sequentially or in parallel (e.g., in a parallel processor or multi-threaded processing environment).

[0069] Figure 1 This is a schematic diagram of the overheat protection principle of the electric power steering system provided in an embodiment of the present invention, specifically as follows: Figure 1As shown, the overheat protection system includes an input module, an adaptive overheat protection control module, and an output module. The adaptive overheat protection control module includes an adaptive function module and an overheat protection module.

[0070] The input information for the adaptive function module includes time data acquired from the vehicle, current collected by the current sensor, temperature collected by the temperature sensor, and overheat protection trigger count N and estimated motor temperature T from the overheat protection module. E The adaptive function module processes the above input information to obtain the current motor temperature T. M Motor allowable temperature T X2 ECU allowable temperature T X1 The output is then sent to the overheat protection module, which adjusts the output based on the current motor temperature T. M Motor allowable temperature T X2 ECU allowable temperature T X1 An overheat protection check is performed, and a current request is generated based on the check result. This current request is then sent to the motor in the output module to control the current flowing to the motor.

[0071] This invention fully utilizes vehicle signals and existing sensor sampling resources, and adds software strategies based on component durability tests and vehicle tests, building upon existing overheat protection technologies to enable the correction of the estimated motor temperature T under various operating conditions. E It also has the ability to predict the allowable temperature of the ECU and motor under various operating conditions, thereby achieving adaptive overheat protection, reducing the risk of burnout of electronic control components, improving system safety, and protecting driver safety.

[0072] Figure 2 This is a flowchart of the overheat protection method for an electric power steering system provided in an embodiment of the present invention, such as... Figure 2 As shown, the overheat protection method for an electric power steering system proposed in this embodiment of the invention may include the following steps:

[0073] S110: Obtain the current ECU temperature T Q ;

[0074] Specifically, the current ECU temperature T is obtained through a temperature sensor installed on the ECU circuit board. Q .

[0075] S120: Determine the current ECU temperature T Q Does it exceed the ECU's allowable temperature T? X1 ;

[0076] S130: Obtain the motor input current, the running time Ts of the electric power steering system, and the number of overheat protection triggers N;

[0077] Specifically, the motor input current is obtained through a current sensor installed on the ECU circuit board. The motor input current is the current output from the ECU circuit board to the motor.

[0078] S140: Estimate the current motor temperature T based on the motor input current, running time Ts, and overheat protection trigger count N. M ;

[0079] The running time Ts represents the historical operating time of the electric power steering system.

[0080] Among them, the number of times the overheat protection is triggered is N, which is the number of times the overheat protection function of the electric power steering system is triggered. Each time the overheat protection is triggered, the number of times the overheat protection is triggered is incremented by a preset step.

[0081] In this embodiment of the invention, the current motor temperature T is estimated based on the motor input current, running time Ts, and the number of overheat protection triggers N. M By coupling the motor temperature estimation model with the motor's usage conditions, the motor temperature estimation model is transformed from a fixed algorithm into a dynamically changing model, which adapts to the motor's state under different life cycles, thereby improving the accuracy of motor temperature estimation.

[0082] S150: Determine the current motor temperature T M Does it exceed the allowable temperature T of the motor? X2 ;

[0083] S160: At the current ECU temperature T Q Exceeding the allowable temperature T of the ECU X1 And / or, the current temperature T of the motor M Exceeding the allowable temperature T of the motor X2 When the overheat protection is triggered, the overheat protection trigger count N is updated.

[0084] Specifically, updating the overheat protection trigger count N can be done by incrementing the overheat protection trigger count N by a preset step size A (A∈N). + Then, the value is assigned to the overheat protection trigger count, i.e., the updated overheat protection trigger count N = N + A. For example, the preset step size A = 1, the current overheat protection trigger count N = 4, and the updated preset step size N = 5. For example, the preset step size A = 2, the current overheat protection trigger count N = 4, and the updated preset step size N = 6.

[0085] Based on the hardware of existing technical solutions, this invention achieves adaptive control of overheat protection for electric power steering systems through software algorithms. It does not require any additional material costs, is easy to implement, improves functional safety, and has high reliability.

[0086] Figure 3This is a flowchart of step S140 provided in an embodiment of the present invention, specifically as follows: Figure 3 As shown, the current motor temperature T is estimated based on the motor input current, running time Ts, and the number of overheat protection triggers N. M It may include the following steps:

[0087] S141: Estimate the current motor temperature T based on the motor input current. M The estimated motor temperature T is obtained. E ;

[0088] S142: Determine the first temperature gain value Gain1 corresponding to the running time Ts according to the first correspondence;

[0089] Among them, the first correspondence is the correspondence between the running time Ts and the first temperature gain value Gain1;

[0090] S143: Determine the second temperature gain value Gain2 corresponding to the number of overheat protection triggers N according to the second correspondence;

[0091] Among them, the second correspondence is the correspondence between the number of overheat protection triggers N and the second temperature gain value Gain2;

[0092] S144: Based on the estimated motor temperature T E The current temperature T of the motor is obtained by using the first temperature gain value Gain1 and the second temperature gain value Gain2. M .

[0093] In one embodiment, the estimated motor temperature T E Multiply by the first temperature gain value Gain1 to obtain the estimated motor temperature T. E Multiply the product by the second temperature gain value Gain2, and then sum the two products using a weighted method to obtain the adjusted current motor temperature T. M =a*T M *Gain1+b*T M *Gain2, where a+b=1, 0 <a<1,0<b<1。

[0094] In one embodiment, the estimated motor temperature T E Multiplying the first temperature gain value Gain1 and the second temperature gain value Gain2 by the adjusted current temperature T of the motor is obtained. M =T M *Gain1*Gain2.

[0095] Adjusted motor current temperature T M Since it is related to both the running time Ts and the number of times the overheat protection is triggered N, it can more accurately reflect the actual temperature of the motor at present.

[0096] In this embodiment of the invention, the current motor temperature T is estimated based on the motor input current, running time Ts, and the number of overheat protection triggers N. M Compared with existing technologies, this improves the accuracy of motor temperature estimation.

[0097] Specifically, estimate the current motor temperature T based on the motor input current. M Previously, including:

[0098] Obtain the pre-established correspondence curve; where the correspondence curve is used to describe the current motor temperature T. M Motor temperature estimate T E The relationship between the number of overheat protection triggers (N) and the running time (Ts); establishing the corresponding relationship curve, which may include: collecting the current motor temperature (T) through motor testing. M Motor temperature estimate T E Based on the overheat protection trigger count N and running time Ts data, plot the current motor temperature T. M Motor temperature estimate T E The relationship curve between the number of overheat protection triggers N and the running time Ts.

[0099] Determine the current motor temperature T corresponding to the running time Ts based on the corresponding relationship curve. M And the estimated value of motor temperature T E ;

[0100] Based on the current motor temperature T corresponding to the running time Ts M And the estimated value of motor temperature T E Calculate the first temperature gain value Gain1 corresponding to the running time Ts to obtain the first correspondence; the first correspondence is the correspondence between the running time Ts and the first temperature gain value Gain1, and the first temperature gain value Gain1 is a set of data related to the running time Ts.

[0101] After obtaining the first correspondence, the method also includes: storing the first correspondence in the ECU's non-volatile memory (NVM).

[0102] Determine the current motor temperature T corresponding to the number of overheat protection triggers N based on the corresponding relationship curve. M And the estimated value of motor temperature T E ;

[0103] Based on the current motor temperature T corresponding to the number of overheat protection triggers N. M And the estimated value of motor temperature T EThe second temperature gain value Gain2 corresponding to the number of overheat protection triggers N is calculated, thus obtaining the second correspondence. The second correspondence is the relationship between the number of overheat protection triggers N and the second temperature gain value Gain2, where the second temperature gain value Gain2 is a set of data related to N;

[0104] Specifically, after obtaining the second correspondence, the process also includes storing the second correspondence in the ECU's non-volatile memory NVM.

[0105] In existing technologies, the allowable temperature for the ECU and motor is a recommended value (constant) provided in the component's user manual. However, after prolonged operation under the complex environmental conditions of the vehicle (humidity, electromagnetic fields, air pressure, etc.), the allowable temperature of the ECU and motor will change. Using the allowable temperature (constant) of the ECU and motor as the safety threshold for triggering overheat protection throughout their entire lifespan is unreasonable. When the allowable temperature of the electronic control components decreases during their service life, and the overheat protection is not triggered, the ECU and motor may be unable to withstand the current temperature and burn out. Therefore, some embodiments also include setting the allowable temperature T for the ECU and motor. X2 Make adaptive adjustments.

[0106] Figure 4 This is a flowchart of the ECU allowable temperature update provided in an embodiment of the present invention, specifically as follows: Figure 4 As shown, after triggering the overheat protection and updating the overheat protection trigger count N, the following steps are also included:

[0107] S210: Obtain the square of the equivalent current per unit time I when the ECU last triggered overheat protection. M1 2 ;

[0108] S220: Obtain the square of the equivalent current per unit time I when the ECU triggers overheat protection. M1 2 ;

[0109] Specifically, obtain the square of the equivalent current per unit time I when the ECU triggers overheat protection. M1 2 Previously, it was necessary to compare the running time Ts with the allowable ECU temperature T. X1 The start time T of the change K1 Determine whether the ECU's allowable temperature adaptive function is enabled, specifically including:

[0110] Obtain the allowable temperature T of the ECU X1 The start time of the change is taken as the first start time T. K1 ; where the first start time T K1 It was determined through ECU durability and performance testing;

[0111] Determine if the running time Ts is greater than or equal to the first start time T. K1 ;

[0112] If so, the ECU's allowable temperature adaptive function is activated, and the steering wheel obtains the square of the equivalent current per unit time I when the ECU triggers overheat protection. M1 2 Steps;

[0113] If not, then the ECU allowable temperature adaptive function is not enabled, and the process returns to obtaining the ECU allowable temperature T. X1 The start time of the change is taken as the first start time T. K1 This is to continuously monitor whether the ECU's allowable temperature adaptive function is enabled.

[0114] S230: Calculate the square of the equivalent current per unit time I when the ECU triggers overheat protection. M1 2 The square of the equivalent current per unit time when the ECU last triggered overheat protection. M1 2 The ratio is taken as the first ratio P1;

[0115] Specifically, the initial value of P1 is 1. To prevent this function from affecting ECU performance, the calculated P1 value is usually limited.

[0116] S240: Determine whether the first ratio P1 is greater than or equal to the preset threshold p1;

[0117] Specifically, the preset threshold p1 is determined through experiments.

[0118] S250: If so, based on the ECU's allowable temperature T X1 Update the ECU allowable temperature T with the first ratio P1. X1 The updated ECU allowable temperature T X1 As the allowable temperature T of the ECU X1 ;

[0119] In other words, the ECU allowable temperature T is updated every time the ECU overheat protection is triggered and the P1 value is determined to be out of limit. X1 ;

[0120] Specifically, after step S250, the process also includes: updating the ECU allowable temperature T. X1 The NVM written to the ECU serves as the ECU's allowable temperature T for the next overheat protection test. X1 ;

[0121] Specifically, T X1 The initial value is the ECU's recommended allowable temperature.

[0122] S260: If not, maintain the ECU's allowable temperature T X1 constant.

[0123] This invention can continuously update the allowable temperature T of the ECU based on the conditions during ECU use. X1 To ensure the ECU's allowable temperature T X1 It can adapt to different working conditions.

[0124] Figure 5 This is a flowchart of updating the allowable temperature of the motor provided in an embodiment of the present invention, specifically as follows: Figure 5 As shown, after triggering the overheat protection and updating the overheat protection trigger count N, the following steps are also included:

[0125] S310: Obtain the square of the equivalent current per unit time I when the motor last triggered overheat protection. M2 2 ;

[0126] S320: Obtain the square of the equivalent current per unit time I when the motor triggers overheat protection. M2 2 ;

[0127] Specifically, obtain the square of the equivalent current per unit time I when the motor triggers overheat protection. M2 2 Before using it as the second entry value, it is necessary to compare the running time Ts with the allowable motor temperature T. X2 The start time T of the change K2 Determine whether the motor's allowable temperature adaptive function is enabled, specifically including:

[0128] Obtain the allowable temperature T of the motor X2 The start time of the change is taken as the second start time T. K2 ;

[0129] Determine if the running time Ts is greater than or equal to the second start time T. K2 Among them, the second start time T K2 Determined through motor durability and performance tests;

[0130] If so, the motor's allowable temperature adaptive function is activated, and the direction is determined by obtaining the square of the equivalent current per unit time I when the motor triggers overheat protection. M2 2 Steps;

[0131] If not, the motor allowable temperature adaptive function is not enabled, and the process returns to obtaining the motor allowable temperature T. X2 The start time of the change is taken as the second start time T. K2 This continuously monitors whether the motor's allowable temperature adaptive function is enabled.

[0132] S330: Calculate the square of the equivalent current per unit time I when the motor triggers overheat protection. M2 2 The square of the equivalent current per unit time when the motor overheat protection was triggered last time. M2 2 The ratio is taken as the second ratio P2;

[0133] Specifically, the initial value of P2 is 1. To prevent this function from affecting ECU performance, the calculated P2 value is usually limited.

[0134] S340: Determine whether the second ratio P2 is greater than or equal to the preset threshold p2;

[0135] Specifically, the preset threshold p2 was determined through experiments.

[0136] S350: If so, according to the allowable motor temperature T X2 The second ratio P2 updates the allowable motor temperature T. X2 The updated allowable temperature T of the motor X2 As the allowable temperature T of the motor X2 ;

[0137] In other words, the allowable motor temperature T is updated every time the motor overheat protection is triggered and the P2 value is determined to be out of limit. X2 ;

[0138] Specifically, after step S250, the method also includes: updating the allowable motor temperature T. X2 The NVM written to the ECU serves as the allowable motor temperature T for the next overheat protection decision. X2 ;

[0139] Specifically, T X2 The initial value is the recommended allowable temperature for the motor.

[0140] S360: If not, maintain the allowable motor temperature T X2 constant.

[0141] The embodiments of the present invention can continuously update the allowable temperature T of the motor based on the conditions of the motor during use. X2 To ensure the allowable temperature T of the motor X2 It can adapt to different working conditions.

[0142] It should be noted that the present invention is not limited to the described order of actions, because according to the present invention, some steps may be performed in other orders or simultaneously.

[0143] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0144] Figure 6 This is a structural block diagram of the overheat protection device for the electric power steering system provided in an embodiment of the present invention, specifically as follows: Figure 6 As shown, the electric power steering system overheat protection device proposed in this embodiment of the invention may include the following modules:

[0145] ECU temperature acquisition module 410 is used to acquire the current ECU temperature T. Q ;

[0146] The first trigger judgment module 420 is used to determine the current temperature T of the ECU. Q Does it exceed the ECU's allowable temperature T? X1 ;

[0147] Data acquisition module 430 is used to acquire motor input current, electric power steering system running time Ts and overheat protection trigger count N;

[0148] The motor temperature estimation module 440 is used to estimate the current motor temperature T based on the motor input current, running time Ts, and overheat protection trigger count N. M ;

[0149] The second trigger judgment module 450 is used to determine the current temperature T of the motor. M Does it exceed the allowable temperature T of the motor? X2 ;

[0150] Overheat protection module 460 is used to protect the ECU at its current temperature T. Q Exceeding the allowable temperature T of the ECU X1 And / or, the current temperature T of the motor M Exceeding the allowable temperature T of the motor X2 When the overheat protection is triggered, the overheat protection trigger count N is updated.

[0151] Embodiments of the present invention also provide a vehicle including the electric power steering system overheat protection device provided in the embodiments of the present invention. It should be noted that, without departing from the scope of the embodiments of the present invention, the vehicle referred to here can be a truck, SUV, van, motorhome, or any other type of vehicle.

[0152] Embodiments of the present invention also provide an electronic device, which includes a processor and a memory. The memory stores at least one instruction, at least one program, code set, or instruction set. The processor loads and executes the at least one instruction, at least one program, code set, or instruction set to implement the electric power steering system overheat protection method as described in the method embodiment.

[0153] Embodiments of the present invention also provide a storage medium, which may be disposed in a server to store at least one instruction, at least one program, code set, or instruction set related to implementing the electric power steering system overheat protection method in the method embodiments. The at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by the processor to implement the electric power steering system overheat protection method provided in the above method embodiments.

[0154] Optionally, in this embodiment, the storage medium may be located at at least one of the multiple network servers in a computer network. Optionally, in this embodiment, the storage medium may include, but is not limited to, various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0155] As can be seen from the embodiments of the electric power steering system overheat protection method, device, equipment or storage medium provided by the present invention, the embodiments of the present invention have the ability to correct the estimated value of motor temperature under various operating conditions and predict the allowable temperature of ECU and motor under various operating conditions, thereby realizing the adaptive overheat protection function. This can solve the problem of the electric power steering system overheat protection function not activating in time, reduce the risk of electronic control components being burned out, further improve the safety of the electric power steering system, and protect the safety of the driver.

[0156] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, specific embodiments have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in a different order than that shown in the embodiments and still achieve the desired result. Additionally, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0157] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device and server embodiments are basically similar to the method embodiments, so the descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0158] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0159] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electric power steering system overheat protection method, characterized by, The method comprises: obtaining a current temperature of a control unit; determining whether the current temperature of the control unit exceeds a permissible temperature of the control unit; obtaining a motor input current, a running time of an electric power steering system, and a number of times of triggering an overheat protection; estimating a current temperature of the motor according to the motor input current, to obtain a motor temperature estimation value; determining a first temperature gain value corresponding to the running time according to a first correspondence relationship, wherein the first correspondence relationship is a correspondence relationship between the running time and the first temperature gain value; determining a second temperature gain value corresponding to the number of times of triggering the overheat protection according to a second correspondence relationship, wherein the second correspondence relationship is a correspondence relationship between the number of times of triggering the overheat protection and the second temperature gain value; obtaining a current temperature of the motor according to the motor temperature estimation value, the first temperature gain value, and the second temperature gain value; determining whether the current temperature of the motor exceeds a permissible temperature of the motor; when the current temperature of the control unit exceeds the permissible temperature of the control unit and / or the current temperature of the motor exceeds the permissible temperature of the motor, triggering the overheat protection and updating the number of times of triggering the overheat protection.

2. The method of claim 1, wherein, Before the step of estimating the current temperature of the motor according to the motor input current, the method comprises: obtaining a pre-established correspondence curve, wherein the correspondence curve is used to describe a relationship among the current temperature of the motor, the motor temperature estimation value, the number of times of triggering the overheat protection, and the running time; determining the current temperature of the motor and the motor temperature estimation value corresponding to the running time according to the correspondence curve; calculating the first temperature gain value corresponding to the running time according to the current temperature of the motor and the motor temperature estimation value corresponding to the running time, to obtain the first correspondence relationship; determining the current temperature of the motor and the motor temperature estimation value corresponding to the number of times of triggering the overheat protection according to the correspondence curve; calculating the second temperature gain value corresponding to the number of times of triggering the overheat protection according to the current temperature of the motor and the motor temperature estimation value corresponding to the number of times of triggering the overheat protection, to obtain the second correspondence relationship.

3. The method of claim 1, wherein, After the step of triggering the overheat protection and updating the number of times of triggering the overheat protection, the method further comprises: obtaining a square of an equivalent current per unit time when the overheat protection was triggered last time; obtaining a square of an equivalent current per unit time when the overheat protection is triggered this time; calculating a ratio of the square of the equivalent current per unit time when the overheat protection is triggered this time to the square of the equivalent current per unit time when the overheat protection was triggered last time as a first ratio; determining whether the first ratio is greater than or equal to a preset threshold value; if yes, updating the permissible temperature of the control unit according to the permissible temperature of the control unit and the first ratio, and taking the updated permissible temperature of the control unit as the permissible temperature of the control unit; if no, keeping the permissible temperature of the control unit unchanged.

4. The method of claim 3, wherein, Before the step of obtaining the square of the equivalent current per unit time when the overheat protection is triggered this time, the method comprises: obtaining a starting time of a change of the permissible temperature of the control unit as a first starting time; Determine whether the running time is greater than or equal to the first start time; If so, proceed to the step of obtaining the square of the equivalent current per unit time when the control unit triggers overheat protection.

5. The method of claim 1, wherein, After triggering the overheat protection and updating the overheat protection trigger count, the method further includes: Get the square of the equivalent current per unit time when the motor last triggered overheat protection; Obtain the square of the equivalent current per unit time when the motor triggers overheat protection; The second ratio is calculated as the ratio of the square of the equivalent current per unit time when the motor triggers overheat protection this time to the square of the equivalent current per unit time when the motor triggers overheat protection last time. Determine whether the second ratio is greater than or equal to a preset threshold; If so, update the allowable motor temperature according to the allowable motor temperature and the second ratio, and use the updated allowable motor temperature as the allowable motor temperature; If not, keep the allowable temperature of the motor constant.

6. The method of claim 5, wherein, Before obtaining the square of the equivalent current per unit time when the motor triggers overheat protection as the second entry value, the following steps are included: The start time of the allowable temperature change of the motor is obtained as the second start time; Determine whether the running time is greater than or equal to the second start time; If so, proceed to the step of obtaining the square of the equivalent current per unit time when the motor triggers overheat protection.

7. An electric power steering system overheat protection device, characterized by comprising: include: The control unit temperature acquisition module is used to acquire the current temperature of the control unit; The first trigger judgment module is used to determine whether the current temperature of the control unit exceeds the allowable temperature of the control unit; The data acquisition module is used to acquire the motor input current, the running time of the electric power steering system, and the number of overheat protection triggers; The motor temperature estimation module is used to estimate the current motor temperature based on the motor input current to obtain an estimated motor temperature value; determine a first temperature gain value corresponding to the running time based on a first correspondence relationship, wherein the first correspondence relationship is the correspondence between the running time and the first temperature gain value; determine a second temperature gain value corresponding to the number of overheat protection triggers based on a second correspondence relationship, wherein the second correspondence relationship is the correspondence between the number of overheat protection triggers and the second temperature gain value; and obtain the current motor temperature based on the estimated motor temperature value, the first temperature gain value, and the second temperature gain value. The second trigger judgment module is used to determine whether the current temperature of the motor exceeds the allowable temperature of the motor. An overheat protection module is used to trigger overheat protection and update the overheat protection trigger count when the current temperature of the control unit exceeds the allowable temperature of the control unit, and / or the current temperature of the motor exceeds the allowable temperature of the motor.

8. An electronic device, comprising: The electronic device includes a processor and a memory, the memory storing at least one instruction or at least one program, the at least one instruction or the at least one program being loaded and executed by the processor to implement the overheat protection method for the electric power steering system as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The storage medium stores at least one instruction or at least one program segment, which is loaded and executed by a processor to implement the electric power steering system overheat protection method as described in any one of claims 1 to 6.

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