Online evaluation method and system for current performance of electric vehicle

Abstract

The invention discloses an electric vehicle current performance online evaluation method and system, and the method comprises the steps: obtaining the real-time average target current of a motor and the real-time average actual current of the motor; calculating motor current performance evaluation parameters, calculating a plurality of instantaneous output target current change rates of the motor, obtaining the average change slope of the motor output target current, the maximum change rate of the motor instantaneous output target current and the minimum change rate of the motor instantaneous output target current, and calculating a comprehensive fitting value of the motor current slope; according to the method, the motor current performance theoretical value is calculated, and the motor current performance evaluation parameter is compared with the motor current performance theoretical value, so that the consistency of the actual current and the target current of the motor can be identified online and accurately in real time, the problem of safe driving caused by current abnormity can be prevented, and important and basic guarantee is provided for safe driving of the electric vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of motor drive technology, and in particular to an online evaluation method and system for electric vehicle current performance. Background Art

[0002] Electric vehicles are driven by electric motors. Precise control of motor torque is required by controlling the motor current. However, sensor, mechanical, or coil failures can cause the actual motor current to misalign with the target current, leading to abnormal motor torque. This can cause driving anomalies and potentially lead to safety accidents. Therefore, online evaluation of the consistency between the actual motor current and the target current is essential to proactively prevent safety issues caused by current anomalies. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an online evaluation method and system for the current performance of an electric vehicle in response to the deficiencies in the prior art. The method can prevent safety driving problems caused by abnormal current.

[0004] To achieve the above object, according to one aspect of the present invention, a method for online evaluation of electric vehicle current performance is provided, comprising:

[0005] Calculating a real-time average target current of the motor and a real-time average actual current of the motor based on multiple instantaneous target currents of the motor outputs and multiple instantaneous actual currents of the motor;

[0006] Calculating a motor current performance evaluation parameter based on the real-time average target current of the motor and the real-time average actual current of the motor;

[0007] Calculate multiple instantaneous output target current change rates of the motor in the task cycle based on the output instantaneous target current of the motor at adjacent moments;

[0008] Calculating an average change slope of the motor output target current based on a plurality of instantaneous output target current change rates of the motor;

[0009] Calculating a maximum rate of change of the instantaneous output target current of the motor and a minimum rate of change of the instantaneous output target current of the motor based on the multiple rates of change of the instantaneous output target current of the motor;

[0010] Calculating a motor current slope comprehensive fitting value based on an average change slope of the motor output target current, a maximum change rate of the motor instantaneous output target current, and a minimum change rate of the motor instantaneous output target current;

[0011] Calculate the theoretical value of motor current performance based on the motor current slope comprehensive fitting value, the task cycle, and the safety factor;

[0012] Calculating a motor current performance difference value based on the motor current performance theoretical value and the motor current performance evaluation parameter;

[0013] The motor current performance state is determined based on the motor current performance difference value and the motor current difference threshold.

[0014] In the above solution, the multiple instantaneous target currents output by the motor can be calculated and valued in real time according to control requirements; the multiple instantaneous actual currents of the motor are obtained through current sensors.

[0015] In the above solution, the motor current performance evaluation parameter is the absolute value of the difference between the real-time average target current of the motor and the real-time average actual current of the motor.

[0016] In the above solution, the change rates of the multiple instantaneous output target currents of the motor are the absolute value of the difference between the output instantaneous target currents of the motor at adjacent moments divided by the task period; the task period is a preset value.

[0017] In the above scheme, the comprehensive fitting value of the motor current slope is the sum of the product of the average change slope of the motor output target current and the first performance fitting coefficient, the product of the maximum change rate of the motor instantaneous output target current and the second performance fitting coefficient, and the product of the minimum change rate of the motor instantaneous output target current and the third performance fitting coefficient; the first performance fitting coefficient, the second performance fitting coefficient, and the third performance fitting coefficient are all motor performance parameters, which are obtained through calibration.

[0018] In the above solution, the theoretical value of the motor current performance is the product of the comprehensive fitting value of the motor current slope, the task cycle, and the safety factor; the safety factor is a preset value.

[0019] In the above solution, the motor current performance difference value is the absolute value of the difference between the motor current performance theoretical value and the motor current performance evaluation parameter.

[0020] In the above scheme, the specific method for determining the motor current performance status based on the motor current performance difference value and the motor current difference threshold is: if the motor current performance difference value is not greater than the motor current difference threshold, the motor current performance status is determined to be normal; if the motor current performance difference value is greater than the motor current difference threshold, the motor current performance status is determined to be abnormal; wherein the motor current difference threshold is a preset value.

[0021] In the above scheme, when the motor current performance status is abnormal, the abnormal status of the motor current performance status will be displayed on the vehicle's instrument display device as an alarm, and a prompt will be given to repair and inspect the motor to prevent the fault from further aggravating and affecting driving safety. At the same time, the vehicle enters the limp home protection mode.

[0022] The present invention also proposes an online evaluation system for electric vehicle current performance, comprising:

[0023] A first calculation module is used to calculate the real-time average target current of the motor and the real-time average actual current of the motor based on multiple instantaneous target currents of the motor output and multiple instantaneous actual currents of the motor;

[0024] A second calculation module is used to calculate a motor current performance evaluation parameter based on the real-time average target current of the motor and the real-time average actual current of the motor;

[0025] A third calculation module is used to calculate multiple instantaneous output target current change rates of the motor in the task cycle based on the output instantaneous target current of the motor at adjacent moments;

[0026] a fourth calculation module, configured to calculate an average change slope of the motor output target current based on a plurality of instantaneous output target current change rates of the motor;

[0027] a fifth calculation module, configured to calculate a maximum rate of change of the instantaneous output target current of the motor and a minimum rate of change of the instantaneous output target current of the motor based on the multiple rates of change of the instantaneous output target current of the motor;

[0028] a sixth calculation module, configured to calculate a motor current slope comprehensive fitting value based on an average change slope of the motor output target current, a maximum change rate of the motor instantaneous output target current, and a minimum change rate of the motor instantaneous output target current;

[0029] a seventh calculation module, configured to calculate a theoretical value of motor current performance based on the motor current slope comprehensive fitting value, the task cycle, and a safety factor;

[0030] an eighth calculation module, configured to calculate a motor current performance difference value based on the motor current performance theoretical value and the motor current performance evaluation parameter;

[0031] A determination module is used to determine the motor current performance state based on the motor current performance difference value and the motor current difference threshold.

[0032] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0033] The present invention provides an online evaluation method for electric vehicle current performance. The method obtains the real-time average target current and the real-time average actual current of the motor, calculates the motor current performance evaluation parameters, calculates the change rates of multiple instantaneous output target currents of the motor, obtains the average change slope of the motor output target current, the maximum change rate of the motor instantaneous output target current and the minimum change rate of the motor instantaneous output target current, calculates the comprehensive fitting value of the motor current slope and the theoretical value of the motor current performance, and compares the motor current performance evaluation parameters with the theoretical value of the motor current performance. The method can accurately identify the consistency between the actual current and the target current of the motor in real time online, prevent safe driving problems caused by current anomalies, and provide important and basic guarantees for the safe driving of electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. Throughout the drawings, the same reference figures denote the same components. In the drawings:

[0035] Figure 1 The figure is a flow chart of an online evaluation method for electric vehicle current performance in the first embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0037] It should be understood that the size of the serial numbers of the steps in the embodiment does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0038] It should be noted that the execution entity of the embodiments of this application can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, mobile phone, etc., or an electronic device capable of implementing the above functions, a vehicle digital twin data interaction device based on contract theory, etc. The following uses the vehicle digital twin data interaction device based on contract theory as an example to illustrate this embodiment and the following embodiments.

[0039] Example 1

[0040] The present application embodiment provides an online evaluation method for electric vehicle current performance, such as Figure 1 Shown, including:

[0041] S1, calculating the real-time average target current of the motor and the real-time average actual current of the motor based on multiple instantaneous target currents of the motor output and multiple instantaneous actual currents of the motor.

[0042] In the embodiment of the present application, it should be noted that the real-time average target current of the motor is equal to the sum of n output instantaneous target currents divided by n; the real-time average actual current of the motor is equal to the sum of n instantaneous actual currents divided by n; specifically, the calculation formulas for the real-time average target current of the motor and the real-time average actual current of the motor are:

[0043]

[0044] in, is the real-time average target current of the motor; Itartget(j) is the instantaneous target current of the j-th output of the motor, which can be calculated in real time according to the control requirements; is the real-time average actual current of the motor; Iactual(j) is the jth instantaneous actual current of the motor, obtained by the current sensor; n is the total number of data, which is 20 in this embodiment, j∈[1,n].

[0045] S2, calculating the motor current performance evaluation parameter based on the real-time average target current and the real-time average actual current of the motor.

[0046] Specifically, in the embodiment of the present application, the motor current performance evaluation parameter is the absolute value of the difference between the real-time average target current of the motor and the real-time average actual current of the motor. The calculation formula of the motor current performance evaluation parameter is:

[0047]

[0048] in, It is the motor current performance evaluation parameter.

[0049] S3, calculating a plurality of instantaneous output target current change rates of the motor in the task cycle based on the output instantaneous target currents of the motor at adjacent moments.

[0050] Specifically, in the embodiment of the present application, the change rates of multiple instantaneous output target currents of the motor are the absolute value of the difference between the output instantaneous target currents of the motor at adjacent moments divided by the task period; the calculation formula for the change rates of multiple instantaneous output target currents of the motor is:

[0051]

[0052] Among them, KI(j) is the rate of change of the j-th instantaneous output target current of the motor; Itartget(j-1) is the j-1-th output instantaneous target current of the motor, Itartget(j-1) and Itartget(j) are the output instantaneous target currents at adjacent moments; Δt is the task period, which is a preset value and is 10s in the embodiment of the present application.

[0053] S4, calculating an average change slope of the motor output target current based on multiple instantaneous output target current change rates of the motor.

[0054] Specifically, in the embodiment of the present application, the average change slope of the motor output target current is equal to the sum of the instantaneous change rates of the motor output target current divided by n. The calculation formula for the average change slope of the motor output target current is:

[0055]

[0056] in, The average change slope of the motor output target current.

[0057] S5, calculating a maximum rate of change of the instantaneous output target current of the motor and a minimum rate of change of the instantaneous output target current of the motor based on a plurality of rates of change of the instantaneous output target current of the motor.

[0058] Specifically, in the embodiment of the present application, the maximum rate of change of the instantaneous output target current of the motor is equal to the maximum value among the n rates of change of the instantaneous output target current of the motor; the minimum rate of change of the instantaneous output target current of the motor is equal to the minimum value among the n rates of change of the instantaneous output target current of the motor. Specifically, the maximum rate of change of the instantaneous output target current of the motor and the minimum rate of change of the instantaneous output target current of the motor are calculated as follows:

[0059]

[0060] Among them, KI max KI is the maximum rate of change of the instantaneous output target current of the motor; min It is the minimum rate of change of the instantaneous output target current of the motor.

[0061] S6, calculating a motor current slope comprehensive fitting value based on an average change slope of the motor output target current, a maximum change rate of the motor instantaneous output target current, and a minimum change rate of the motor instantaneous output target current.

[0062] Specifically, in the embodiment of the present application, it should be noted that the comprehensive fitting value of the motor current slope is the sum of the product of the average change slope of the motor output target current and the first performance fitting coefficient, the product of the maximum change rate of the motor instantaneous output target current and the second performance fitting coefficient, and the product of the minimum change rate of the motor instantaneous output target current and the third performance fitting coefficient; specifically, the calculation formula of the motor current performance difference fitting value is:

[0063]

[0064] Wherein, KI1 is the comprehensive fitting value of the motor current slope; β1 is the first performance fitting coefficient; β2 is the second performance fitting coefficient; and β3 is the third performance fitting coefficient. The first, second, and third performance fitting coefficients are all motor performance parameters obtained through calibration. In this embodiment, the first performance fitting coefficient β1 is 0.3, the second performance fitting coefficient β2 is 0.3, and the third performance fitting coefficient β3 is 0.4.

[0065] S7 calculates the theoretical value of motor current performance based on the comprehensive fitting value of motor current slope, duty cycle, and safety factor.

[0066] Specifically, in the embodiment of the present application, the theoretical value of the motor current performance is the product of the motor current slope comprehensive fitting value, the duty cycle, and the safety factor. Specifically, the calculation formula of the theoretical value of the motor current performance is:

[0067]

[0068] in, is the theoretical value of the motor current performance; δ is the safety factor, which is a preset value and is 1 in the embodiment of the present application.

[0069] S8, calculating a motor current performance difference value based on the motor current performance theoretical value and the motor current performance evaluation parameter.

[0070] Specifically, in the embodiment of the present application, the motor current performance difference value is the absolute value of the difference between the motor current performance theoretical value and the motor current performance evaluation parameter; specifically, the calculation formula of the motor current performance difference value is:

[0071]

[0072] in, is the motor current performance difference value.

[0073] S9, determining the motor current performance state based on the motor current performance difference value and the motor current difference threshold.

[0074] Specifically, in the embodiment of the present application, the specific method for determining the motor current performance state based on the motor current performance difference value and the motor current difference threshold is: if the motor current performance difference value is not greater than the motor current difference threshold, then the motor current performance state is determined to be normal; if the motor current performance difference value is greater than the motor current difference threshold, then the motor current performance state is determined to be abnormal; specifically, the determination formula for the motor current performance state is:

[0075]

[0076] Among them, FLag is the motor current performance status; is the motor current difference threshold, which is a preset value. In the embodiment of the present application, the motor current difference threshold is 3 A. It can be understood that when FLag is 1, the motor current performance state is determined to be normal; when FLag is 0, the motor current performance state is determined to be abnormal.

[0077] Example 2

[0078] On the one hand, the embodiment of the present application provides an online evaluation method for electric vehicle current performance. The principles and steps of this embodiment are basically the same as those of Example 1, except that the method further includes:

[0079] When the motor current performance status is abnormal, the abnormal status of the motor current performance status will be displayed on the vehicle's instrument display device as an alarm, and a prompt will be given to repair and inspect the motor to prevent the fault from further aggravating and affecting driving safety. At the same time, the vehicle enters the limp home protection mode.

[0080] Another aspect of the present application is to provide an online evaluation system for electric vehicle current performance, including:

[0081] A first calculation module is used to calculate the real-time average target current of the motor and the real-time average actual current of the motor based on multiple instantaneous target currents of the motor output and multiple instantaneous actual currents of the motor;

[0082] A second calculation module is used to calculate the motor current performance evaluation parameter based on the real-time average target current of the motor and the real-time average actual current of the motor;

[0083] A third calculation module is used to calculate multiple instantaneous output target current change rates of the motor in the task cycle based on the output instantaneous target current of the motor at adjacent moments;

[0084] a fourth calculation module, configured to calculate an average change slope of the motor output target current based on a plurality of instantaneous output target current change rates of the motor;

[0085] a fifth calculation module, configured to calculate a maximum rate of change of the instantaneous output target current of the motor and a minimum rate of change of the instantaneous output target current of the motor based on a plurality of rates of change of the instantaneous output target current of the motor;

[0086] a sixth calculation module, configured to calculate a motor current slope comprehensive fitting value based on an average change slope of the motor output target current, a maximum change rate of the motor instantaneous output target current, and a minimum change rate of the motor instantaneous output target current;

[0087] A seventh calculation module is used to calculate a theoretical value of motor current performance based on a comprehensive fitting value of a motor current slope, a duty cycle, and a safety factor;

[0088] an eighth calculation module, configured to calculate a motor current performance difference value based on the motor current performance theoretical value and the motor current performance evaluation parameter;

[0089] The determination module is used to determine the motor current performance state based on the motor current performance difference value and the motor current difference threshold.

[0090] It should be pointed out that, according to the needs of implementation, the various steps described in this application can be split into more steps, or two or more steps or partial operations of the steps can be combined into new steps to achieve the purpose of the present invention.

[0091] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An online evaluation method for electric vehicle current performance, characterized in that: include: Calculating a real-time average target current of the motor and a real-time average actual current of the motor based on multiple instantaneous target currents of the motor outputs and multiple instantaneous actual currents of the motor; Calculating a motor current performance evaluation parameter based on the real-time average target current of the motor and the real-time average actual current of the motor; Calculate multiple instantaneous output target current change rates of the motor in the task cycle based on the output instantaneous target current of the motor at adjacent moments; Calculating an average change slope of the motor output target current based on a plurality of instantaneous output target current change rates of the motor; Calculating a maximum rate of change of the instantaneous output target current of the motor and a minimum rate of change of the instantaneous output target current of the motor based on the multiple rates of change of the instantaneous output target current of the motor; Calculating a motor current slope comprehensive fitting value based on an average change slope of the motor output target current, a maximum change rate of the motor instantaneous output target current, and a minimum change rate of the motor instantaneous output target current; Calculate the theoretical value of motor current performance based on the motor current slope comprehensive fitting value, the task cycle, and the safety factor; Calculating a motor current performance difference value based on the motor current performance theoretical value and the motor current performance evaluation parameter; The motor current performance state is determined based on the motor current performance difference value and the motor current difference threshold.

2. The method for online evaluation of electric vehicle current performance according to claim 1, characterized in that: The multiple instantaneous target currents output by the motor can be calculated and valued in real time according to control requirements; the multiple instantaneous actual currents of the motor are obtained through current sensors.

3. The online evaluation method for electric vehicle current performance according to claim 1, characterized in that: The motor current performance evaluation parameter is the absolute value of the difference between the real-time average target current of the motor and the real-time average actual current of the motor.

4. The method for online evaluation of electric vehicle current performance according to claim 1, characterized in that: The change rates of the multiple instantaneous output target currents of the motor are the absolute value of the difference between the output instantaneous target currents of the motor at adjacent moments divided by the task period; the task period is a preset value.

5. The method for online evaluation of electric vehicle current performance according to claim 1, characterized in that: The motor current slope comprehensive fitting value is the sum of the product of the average change slope of the motor output target current and the first performance fitting coefficient, the product of the maximum change rate of the motor instantaneous output target current and the second performance fitting coefficient, and the product of the minimum change rate of the motor instantaneous output target current and the third performance fitting coefficient; The first performance fitting coefficient, the second performance fitting coefficient, and the third performance fitting coefficient are all motor performance parameters, which are obtained through calibration.

6. The method for online evaluation of electric vehicle current performance according to claim 1, characterized in that: The theoretical value of the motor current performance is the product of the comprehensive fitting value of the motor current slope, the task cycle, and the safety factor; the safety factor is a preset value.

7. The method for online evaluation of electric vehicle current performance according to claim 1, characterized in that: The motor current performance difference value is the absolute value of the difference between the motor current performance theoretical value and the motor current performance evaluation parameter.

8. The method for online evaluation of electric vehicle current performance according to claim 1, characterized in that: The specific method for determining the motor current performance state based on the motor current performance difference value and the motor current difference threshold is as follows: if the motor current performance difference value is not greater than the motor current difference threshold, determining that the motor current performance state is normal; If the motor current performance difference value is greater than the motor current difference threshold, determining that the motor current performance state is abnormal; The motor current difference threshold is a preset value.

9. The method for online evaluation of electric vehicle current performance according to claim 8, characterized in that: When the motor current performance status is abnormal, the abnormal status of the motor current performance status will be displayed on the vehicle's instrument display device as an alarm, and a prompt will be given to repair and inspect the motor and the motor. At the same time, the vehicle enters the limp home protection mode.

10. An online evaluation system for electric vehicle current performance, characterized in that: include: A first calculation module is used to calculate the real-time average target current of the motor and the real-time average actual current of the motor based on multiple instantaneous target currents of the motor output and multiple instantaneous actual currents of the motor; A second calculation module is used to calculate a motor current performance evaluation parameter based on the real-time average target current of the motor and the real-time average actual current of the motor; A third calculation module is used to calculate multiple instantaneous output target current change rates of the motor in the task cycle based on the output instantaneous target current of the motor at adjacent moments; a fourth calculation module, configured to calculate an average change slope of the motor output target current based on a plurality of instantaneous output target current change rates of the motor; a fifth calculation module, configured to calculate a maximum rate of change of the instantaneous output target current of the motor and a minimum rate of change of the instantaneous output target current of the motor based on the multiple rates of change of the instantaneous output target current of the motor; a sixth calculation module, configured to calculate a motor current slope comprehensive fitting value based on an average change slope of the motor output target current, a maximum change rate of the motor instantaneous output target current, and a minimum change rate of the motor instantaneous output target current; a seventh calculation module, configured to calculate a theoretical value of motor current performance based on the motor current slope comprehensive fitting value, the task cycle, and a safety factor; an eighth calculation module, configured to calculate a motor current performance difference value based on the motor current performance theoretical value and the motor current performance evaluation parameter; A determination module is used to determine the motor current performance state based on the motor current performance difference value and the motor current difference threshold.

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