CN113125955B - Electric automobile and method and system for monitoring performance of driving system of electric automobile - Google Patents
Electric automobile and method and system for monitoring performance of driving system of electric automobile Download PDFInfo
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- CN113125955B CN113125955B CN202110438397.2A CN202110438397A CN113125955B CN 113125955 B CN113125955 B CN 113125955B CN 202110438397 A CN202110438397 A CN 202110438397A CN 113125955 B CN113125955 B CN 113125955B
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/34—Testing dynamo-electric machines
- G01R31/343—Testing dynamo-electric machines in operation
Abstract
The invention provides an electric automobile, and a method and a system for monitoring the performance of a driving system of the electric automobile, which can execute the following steps: in the process of stopping or decelerating the electric automobile each time, detecting the no-load back electromotive force u of a permanent magnet motor of the electric automobile on line; or: automatically starting a test task at regular intervals or at intervals of a preset time length Tt, waiting for the electric automobile to stop or decelerate in real time after automatically starting the test task, and detecting the no-load back electromotive force u of the permanent magnet motor of the electric automobile on line in the waiting process of stopping or decelerating the electric automobile after waiting for the electric automobile to stop or decelerate; and when the no-load back electromotive force u of the permanent magnet motor of the electric automobile is detected each time, monitoring the performance of a driving system of the electric automobile according to the corresponding detected no-load back electromotive force u. The invention is used for increasing the safety of the user in using the vehicle.
Description
Technical Field
The invention relates to the field of electric automobiles, in particular to an electric automobile and a method and a system for monitoring the performance of a driving system of the electric automobile.
Background
An electric vehicle (BEV) is a vehicle that runs with wheels driven by a motor using a vehicle-mounted power supply as power. Because the influence on the environment is smaller than that of the traditional automobile, the automobile is more and more popular.
Permanent magnet synchronous motors (referred to as permanent magnet motors for short) have been increasingly used in the field of electric vehicle driving due to their compact structure, small size, light weight, high efficiency, high torque, high power density, reliable operation, low noise, and other performance characteristics.
The driving motor of the electric automobile is complex in operation road condition, the rotor permanent magnet is easily affected by factors such as temperature, a reverse magnetic field, aging, vibration and chemical environment to generate demagnetization, once the permanent magnet generates an irreversible demagnetization fault, performance indexes of the permanent magnet motor are reduced, operation heating, current increase and torque performance are reduced, the motor can be out of control and scrapped under severe conditions, and if the irreversible demagnetization fault cannot be found or early-warned in time, the safety of a user in vehicle utilization can be seriously affected.
Disclosure of Invention
In view of the above disadvantages in the prior art, the present invention provides an electric vehicle, and a method and a system for monitoring the performance of a driving system of the electric vehicle, which are used for improving the safety of a user in using the vehicle.
In a first aspect, the invention provides a method for monitoring the performance of a driving system of an electric vehicle, wherein the driving system comprises a permanent magnet motor; the method for monitoring the performance of the electric automobile driving system comprises the following steps:
q1: in each parking or deceleration process of the electric automobile, detecting the no-load back electromotive force u of a permanent magnet motor of the electric automobile on line; or: automatically starting a test task at regular intervals or at intervals of a preset time length Tt, waiting for the electric automobile to stop or decelerate in real time after automatically starting the test task, and detecting the no-load back electromotive force u of the permanent magnet motor of the electric automobile on line in the waiting process of stopping or decelerating the electric automobile after waiting for the electric automobile to stop or decelerate;
q2: and when the no-load counter electromotive force u of the permanent magnet motor of the electric automobile is detected every time, monitoring the performance of a driving system of the electric automobile according to the correspondingly detected no-load counter electromotive force u.
Further, the implementation method of the step Q2 is as follows:
and comparing the current detected no-load back electromotive force u with a preset first no-load back electromotive force threshold value T1 and a preset second no-load back electromotive force threshold value T2 in real time, wherein T1 is less than T2, and the method comprises the following steps:
when the comparison result is that u is larger than T2, judging that the performance of the driving system of the electric automobile is good;
when the comparison result is that u is more than T1 and less than or equal to T2, judging that the performance of the driving system of the electric automobile is slightly reduced, and performing early warning on slight demagnetization of the permanent magnet motor of the electric automobile;
and when the comparison result is that u is less than or equal to T1, judging that the performance of the electric automobile driving system is seriously reduced, and carrying out the early warning of the severe demagnetization of the permanent magnet motor of the electric automobile.
Further, the method for monitoring the performance of the driving system of the electric automobile further comprises the following steps:
when the performance of the electric automobile driving system is judged to be slightly reduced and when the performance of the electric automobile driving system is judged to be severely reduced, corresponding demagnetization early warnings are fed back to manufacturers and sellers of the electric automobile through the wireless transmission module respectively.
Further, in the step Q1, the method for detecting the no-load back electromotive force u of the permanent magnet motor of the electric vehicle on line in the process of stopping or decelerating the electric vehicle is as follows:
s1: stopping supplying power to a permanent magnet motor of the electric automobile, and then executing the step S2;
s2: controlling a reverse power generation energy recovery system of the electric automobile to be kept closed, and then executing a step S3;
s3: online measurement of signal output frequency f on stator winding side of permanent magnet motor on electric vehicle sh And a corresponding no-load counter-potential E w Simultaneously acquiring the temperature t of a permanent magnet motor on the electric automobile; then, executing step S4;
s4: according to the rated frequency f of a permanent magnet motor on an electric automobile and f sh And E w By the formula
Calculating reference no-load back electromotive force of permanent magnet motor on electric automobileE0; then step S5 is executed;
s5: according to the temperature t and the reference no-load back electromotive force E 0 Using the formula as E 0b ＝E 0 -(t-tp)×E 0 Standard no-load back electromotive force E of permanent magnet motor on Xk calculation electric automobile 0b In the formula, k is a no-load back electromotive force coefficient of the permanent magnet motor, tp is a preset temperature threshold, and the value range of tp is 20-25 ℃;
s6: obtaining the no-load back electromotive force u, and then recovering power supply to a permanent magnet motor of the electric automobile, wherein u = E 0b 。
Further, the method for monitoring the performance of the driving system of the electric automobile further comprises the following steps:
and generating and displaying a no-load back electromotive force data link curve chart by using the detected no-load back electromotive force u and the corresponding detection time thereof in real time.
Further, the method for monitoring the performance of the driving system of the electric automobile further comprises the following steps:
real-time utilization of detected no-load back electromotive force u and no-load back electromotive force E w And reference no-load counter electromotive force E 0 Generating a three-phase back electromotive force instantaneous value curve graph;
the method for monitoring the performance of the electric automobile driving system further comprises the following steps:
when no-load back electromotive force u is monitored each time, the interval time T between the current monitoring of the no-load back electromotive force u and the last monitoring of the no-load back electromotive force u is respectively recorded;
when no-load back electromotive force u is monitored each time, the correspondingly obtained no-load back electromotive force E is respectively used w Temperature t of permanent magnet motor and reference no-load counter electromotive force E 0 Standard no-load counter electromotive force E 0b The interval time T and the three-phase back electromotive force instantaneous value curve graph are used as a data packet and uploaded to a whole vehicle data center of the electric vehicle for storage.
In a second aspect, the present invention provides a performance monitoring system for a driving system of an electric vehicle, where the driving system includes a permanent magnet motor, and the performance monitoring system includes:
the back electromotive force detection unit is used for detecting the no-load back electromotive force u of the permanent magnet motor of the electric automobile on line in the process of stopping or decelerating the electric automobile each time; or: automatically starting a test task at regular intervals or at intervals of a preset time length Tt, waiting for the electric automobile to stop or decelerate in real time after automatically starting the test task, and detecting the no-load back electromotive force u of the permanent magnet motor of the electric automobile on line in the waiting process of stopping or decelerating the electric automobile after waiting for the electric automobile to stop or decelerate;
and the performance monitoring unit is used for monitoring the performance of the driving system of the electric automobile according to the correspondingly detected no-load back electromotive force u when the no-load back electromotive force u of the permanent magnet motor of the electric automobile is detected every time.
Further, the performance monitoring unit includes:
the comparison module is used for comparing the magnitude of the no-load back electromotive force u detected at the current time with a preset first no-load back electromotive force threshold T1 and a preset second no-load back electromotive force threshold T2 in real time, wherein T1 is smaller than T2;
the first judgment module is used for judging that the performance of the electric automobile driving system is good when the comparison result of the comparison unit is that u is larger than T2;
the second judgment module is used for judging that the performance of the driving system of the electric automobile is slightly reduced when the comparison result of the comparison unit is that the u is more than T1 and less than or equal to T2, and performing early warning on slight demagnetization of the permanent magnet motor of the electric automobile;
and the third judgment module is used for judging that the performance of the driving system of the electric automobile is seriously reduced when the comparison result of the comparison unit is that u is less than or equal to T1, and carrying out the early warning of the severe demagnetization of the permanent magnet motor of the electric automobile.
Further, the back electromotive force detection unit is connected with the output end of the stator winding of the permanent magnet motor, and the method for detecting the no-load back electromotive force u of the permanent magnet motor of the electric vehicle on line in the process of parking or decelerating the electric vehicle by the back electromotive force detection unit is as follows:
s1: stopping supplying power to a permanent magnet motor of the electric automobile, and then executing the step S2;
s2: controlling a reverse power generation energy recovery system of the electric automobile to be kept closed, and then executing a step S3;
s3: on-line measurement of signal output frequency f on stator winding side of permanent magnet motor on electric vehicle sh And a corresponding no-load counter-potential E w Meanwhile, collecting the temperature t of a permanent magnet motor on the electric automobile; then step S4 is executed;
s4: according to the rated frequency f of a permanent magnet motor on an electric automobile and the frequency f sh And E w By the formula
Calculating reference no-load counter electromotive force E of permanent magnet motor on electric automobile 0 (ii) a Then executing step S5;
s5: according to the temperature t and the reference no-load back electromotive force E 0 Using the formula as E 0b ＝E 0 -(t-tp)×E 0 Xk calculates standard no-load back electromotive force E of permanent magnet motor on electric automobile 0b In the formula, k is a no-load back electromotive force coefficient of the permanent magnet motor, tp is a preset temperature threshold, and the value range of tp is 20-25 ℃;
s6, obtaining the no-load back electromotive force u, and then recovering power supply to the permanent magnet motor of the electric automobile, wherein u = E 0b 。
Further, this electric automobile actuating system performance monitoring system still includes:
and the no-load back electromotive force data link curve generating module is configured to generate and display the no-load back electromotive force data link curve by using the detected no-load back electromotive force u and the corresponding detection time.
In a third aspect, the present invention provides an electric vehicle, comprising an electric vehicle body including a complete vehicle control center configured to perform the method of the above aspects.
The beneficial effect of the invention is that,
1. the performance monitoring method and the system for the electric automobile and the driving system of the electric automobile can detect the no-load back electromotive force u of the permanent magnet motor of the electric automobile on line, and can monitor the performance of the driving system of the electric automobile according to the detected no-load back electromotive force u every time when the no-load back electromotive force u of the permanent magnet motor of the electric automobile is detected, so that the improvement of the safety of the electric automobile is facilitated to a certain extent.
2. The performance monitoring method and system for the electric automobile and the electric automobile driving system provided by the invention can perform early warning on the slight demagnetization of the permanent magnet motor of the electric automobile and the serious demagnetization of the permanent magnet motor of the electric automobile, are beneficial to users to timely and clearly know the performance of the driving system of the electric automobile (namely the demagnetization degree of the permanent magnet motor of the electric automobile), and are beneficial to improving the safety of the electric automobile to a certain extent.
3. The method and the system for monitoring the performance of the electric automobile and the driving system of the electric automobile can respectively feed back corresponding demagnetization early warnings to manufacturers and sellers of the electric automobile through the wireless transmission module when judging that the performance of the driving system of the electric automobile is slightly reduced and when judging that the performance of the driving system of the electric automobile is severely reduced, are beneficial to the manufacturers and the sellers of the electric automobiles to know the demagnetization conditions of the permanent magnet motors of the electric automobiles produced or sold by the manufacturers and the sellers in time, are beneficial to reminding electric automobile users (buyers) to timely maintain the permanent magnet motors of the electric automobiles at after-sales positions, and are beneficial to improving the automobile safety of the users to a certain extent.
4. The electric automobile, the method and the system for monitoring the performance of the driving system of the electric automobile can recover power supply to the permanent magnet motor of the electric automobile after the no-load back electromotive force u is obtained every time, and are favorable for ensuring normal use of the electric automobile to a certain extent.
5. The electric automobile and the method for monitoring the performance of the driving system of the electric automobile can generate and display a no-load back electromotive force data link curve graph, and are favorable for a user to visually observe the performance change of a power system of a permanent magnet motor of the electric automobile to a certain extent, so that certain reference data can be provided for the user to safely use the automobile to a certain extent.
In addition, the invention has reliable design principle, convenient realization and very wide application prospect.
Drawings
In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
FIG. 1 is a schematic flow diagram of a method of one embodiment of the present invention.
FIG. 2 is a schematic block diagram of a system of one embodiment of the present invention.
Detailed Description
In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a schematic flow chart of a method for monitoring the performance of an electric vehicle drive system according to an embodiment of the invention. The driving system comprises a permanent magnet motor.
In the present embodiment, the electric vehicle using the permanent magnet motor as the driving system is provided with a permanent magnet motor driver, and the permanent magnet motor driver is used for driving the permanent magnet motor of the electric vehicle, and includes a control unit for controlling the on/off of the permanent magnet motor of the electric vehicle.
In addition, the electric vehicles according to the present specification are each provided with a regenerative power recovery system.
As shown in fig. 1, the method 100 includes:
step 110: in the process of stopping or decelerating the electric automobile each time, detecting the no-load back electromotive force u of the permanent magnet motor of the electric automobile on line; or: the method comprises the steps of automatically starting a test task at regular intervals or at preset time intervals Tt, waiting for the electric automobile to stop or decelerate in real time after the test task is automatically started, and detecting the no-load back electromotive force u of the permanent magnet motor of the electric automobile on line in the waiting process of stopping or decelerating the electric automobile after the electric automobile stops or decelerates.
Specifically, all the steps involved in step 110 for detecting the no-load back electromotive force u of the permanent magnet motor of the electric vehicle on line in the process of parking or decelerating the electric vehicle are: in each parking process of the electric automobile, the following steps are respectively executed:
s1: stopping power supply to a permanent magnet motor of the electric automobile, and then executing the step S2;
s2: controlling a reverse power generation energy recovery system of the electric automobile to be kept closed, and then executing a step S3;
s3: online measurement of signal output frequency f on stator winding side of permanent magnet motor on electric vehicle sh And a corresponding no-load back-emf E w Meanwhile, collecting the temperature t of a permanent magnet motor on the electric automobile; then step S4 is executed;
s4: according to the rated frequency f of a permanent magnet motor on an electric automobile and f sh And E w Using the formula
Calculating reference no-load back electromotive force E of permanent magnet motor on electric automobile 0 (ii) a Then step S5 is executed;
s5: according to the temperature t and the reference no-load back electromotive force E 0 Using the formula as E 0b ＝E 0 -(t-tp)×E 0 Standard no-load back electromotive force E of permanent magnet motor on Xk calculation electric automobile 0b In the formula, k is a no-load back electromotive force coefficient of the permanent magnet motor, tp is a preset temperature threshold, the value range of tp is 20-25 ℃, and the value range of k is 0.01-0.1%;
s6: obtaining the no-load back electromotive force u, and then recovering power supply to a permanent magnet motor of the electric automobile, wherein u = E 0b 。
In the step S1, the permanent magnet motor driver on the electric automobile can be controlled to stop supplying power to the permanent magnet motor of the electric automobile.
In the step S6, the power supply to the permanent magnet motor of the electric automobile can be started by controlling the permanent magnet motor driver on the electric automobile.
Step 120: and when the no-load back electromotive force u of the permanent magnet motor of the electric automobile is detected each time, monitoring the performance of a driving system of the electric automobile according to the corresponding detected no-load back electromotive force u.
Specifically, the implementation method of step 120 is:
and comparing the magnitude of the no-load back electromotive force u detected at the current time with a preset first no-load back electromotive force threshold value T1 and a preset second no-load back electromotive force threshold value T2 in real time, wherein T1 is less than T2, and the method comprises the following steps:
when the comparison result is that u is larger than T2, judging that the performance of the driving system of the electric automobile is good;
when the comparison result is that the u is more than or equal to T1 and less than or equal to T2, judging that the performance of the driving system of the electric automobile is slightly reduced, and performing early warning on slight demagnetization of the permanent magnet motor of the electric automobile;
and when the comparison result is that u is less than or equal to T1, judging that the performance of the driving system of the electric automobile is seriously reduced, and carrying out the early warning of the severe demagnetization of the permanent magnet motor of the electric automobile.
For example, taking an electric vehicle a as an example, the electric vehicle a uses the permanent magnet motor 1 as a driving system, and the electric vehicle a applies the method 100, when in use, a no-load back electromotive force u1 is detected in step 110, correspondingly, step 120 monitors the performance of the driving system of the electric vehicle according to the no-load back electromotive force u1, and the specific implementation method is as follows:
comparing the detected no-load back emf u1 with said first no-load back emf threshold value T1 and with said second no-load back emf threshold value T2 in magnitude, wherein:
when the comparison result is that u1 is larger than T2, judging that the driving system of the electric automobile A has good performance;
when the comparison result is that the u is more than or equal to T1 and less than or equal to T2, judging that the performance of the driving system of the electric automobile A is slightly reduced, and performing early warning on slight demagnetization of the permanent magnet motor of the electric automobile at the moment;
and when the comparison result is that u is less than or equal to T1, judging that the performance of the driving system of the electric automobile A is seriously reduced, and performing the early warning of severe demagnetization of the permanent magnet motor of the electric automobile at the moment.
Still taking the electric vehicle a as an example, when another idle back electromotive force u2 is detected in step 110, correspondingly, step 120 monitors the performance of the driving system of the electric vehicle according to the other idle back electromotive force u2, and the specific implementation method can refer to the idle back electromotive force u1.
It should be noted that, in step 110, "detect the no-load back electromotive force u of the permanent magnet motor of the electric vehicle on line during each parking or deceleration of the electric vehicle" and "automatically start the test task at regular intervals or at preset time intervals Tt, wait for the parking or deceleration of the electric vehicle in real time after automatically starting the test task, and after waiting for the parking or deceleration of the electric vehicle, detect the no-load back electromotive force u of the permanent magnet motor of the electric vehicle on line during the parking or deceleration of the electric vehicle" sequentially record as step L1 and step L1', and then step L1 and step L1' correspond to two mutually independent situations.
When the step 110 is specifically implemented, a person skilled in the art can select to implement the step L1 or implement the step L1' according to actual needs. For the above step 110, if the step L1 is selected to be implemented, the step L1 'is not implemented, and correspondingly, if the step L1' is selected to be implemented, the step L1 is not implemented.
For example, in the embodiment, if the step L1 is selected to be implemented, the method 100 substantially includes:
l1, detecting no-load counter electromotive force u of a permanent magnet motor of the electric automobile on line in each parking or deceleration process of the electric automobile;
step 120: and when the no-load counter electromotive force u of the permanent magnet motor of the electric automobile is detected every time, monitoring the performance of a driving system of the electric automobile according to the correspondingly detected no-load counter electromotive force u.
If the implementation step L1' is selected, the method 100 substantially includes the following steps:
l1', automatically starting a test task regularly or at intervals of preset time Tt, waiting for the electric automobile to stop or decelerate in real time after automatically starting the test task, and detecting the no-load counter electromotive force u of the permanent magnet motor of the electric automobile on line in the process of waiting for the electric automobile to stop or decelerate after waiting for the electric automobile to stop or decelerate;
step 120: and when the no-load back electromotive force u of the permanent magnet motor of the electric automobile is detected each time, monitoring the performance of a driving system of the electric automobile according to the corresponding detected no-load back electromotive force u.
The test task is automatically started at regular intervals or at intervals of a preset time length Tt, and can be executed by a whole vehicle control center of the electric vehicle.
As an exemplary embodiment of the present invention, the method 100 involves measuring the signal output frequency f on the stator winding side of a permanent magnet motor for an electric vehicle sh And a corresponding no-load counter-potential E w The method comprises the following steps:
detecting and recording instantaneous voltage of a stator winding side of a permanent magnet motor on an electric automobile at set time intervals delta t within a preset time period, and generating an instantaneous voltage change curve S by utilizing all recorded instantaneous voltages and respective detection time thereof;
analyzing the instantaneous voltage change curve S, and intercepting a curve segment from the first upper edge zero crossing point to the next upper edge zero crossing point on the instantaneous voltage change curve S, and marking as a target curve segment;
based on the target curve segment, acquiring the instantaneous voltage u corresponding to the first upper edge zero-crossing point 1 And acquiring all instantaneous voltages u on the curve between the two end points of the target curve segment in the recorded instantaneous voltages 2 、u 3 、...、u N-1 And acquiring the next instantaneous voltage u corresponding to the upper edge zero-crossing point corresponding to the next upper edge zero-crossing point N ；
Using expressions
Calculating the signal frequency corresponding to the transient voltage change curve S to obtain the signal output frequency f to be measured sh ；
Based on the above instantaneous voltage u 1 、u 2 、u 3 、...、u N-1 And u N The signal output frequency f is calculated by the following formula (1) or formula (2) sh Corresponding no-load counter-potential E w ：
Wherein, in formula (2): u. u m Is the above instantaneous voltage u 1 、u 2 、u 3 、...、u N-1 And u N Maximum value of-u m Is the above instantaneous voltage u 1 、u 2 、u 3 、...、u N-1 And u N Minimum value of (1).
In specific implementation, the above formula (1) and formula (2) can be alternatively used by those skilled in the art.
In specific implementation, the above-mentioned "zero-crossing point of the rising edge" may be replaced by a "zero-crossing point of the falling edge".
The value of the preset time period may be set by a person skilled in the art according to actual conditions, for example, the value may be set to 15ms (milliseconds), and may also be set to other values.
The value of the time interval Δ t may be set by a person skilled in the art according to actual conditions, for example, the value of Δ t may be set to 1ms, or may be set to other values, where the value is smaller than the preset time period.
In addition, in concrete implementation, any related prior art can be adopted to measure the signal output frequency f of the stator winding side of the permanent magnet motor on the electric automobile sh And a corresponding no-load counter-potential E w 。
As an exemplary embodiment of the present invention, the method for monitoring the performance of the driving system of the electric vehicle further comprises the steps of:
when the performance of the electric automobile driving system is judged to be slightly reduced and when the performance of the electric automobile driving system is judged to be severely reduced, corresponding demagnetization early warnings are fed back to manufacturers and sellers of the electric automobile through the wireless transmission module respectively.
Specifically, when the performance of the driving system of the electric automobile is judged to be slightly reduced, the early warning information of slight demagnetization of the permanent magnet motor of the electric automobile is fed back to manufacturers and sellers of the electric automobile through the wireless transmission module; when the performance of the electric automobile driving system is judged to be seriously reduced, the early warning information of the severe demagnetization of the permanent magnet motor of the electric automobile is fed back to manufacturers and sellers of the electric automobile through the wireless transmission module.
The early warning information of the mild demagnetization of the permanent magnet motor of the electric automobile and the early warning information of the severe demagnetization of the permanent magnet motor of the electric automobile can be set by technicians in the field according to specific conditions.
As an exemplary embodiment of the present invention, the method for monitoring performance of a driving system of an electric vehicle further comprises the steps of: and generating and displaying a no-load back electromotive force data link curve graph by utilizing the detected no-load back electromotive force u and the corresponding detection time thereof in real time. The performance change of the driving system of the electric automobile can be visually checked by a user.
As an exemplary embodiment of the present invention, the method 100 further comprises the steps of:
real-time utilization of detected no-load back electromotive force u and no-load back electromotive force E w And reference no-load counter electromotive force E 0 And generating a three-phase back electromotive force instantaneous value graph.
The method 100 further comprises the steps of:
when no-load back electromotive force u is monitored each time, the interval time T between the current monitoring of the no-load back electromotive force u and the last monitoring of the no-load back electromotive force u is respectively recorded;
at each oneWhen no-load back electromotive force u is monitored, the correspondingly obtained no-load back electromotive force E is respectively detected w Temperature t of permanent magnet motor and reference no-load counter electromotive force E 0 Standard no-load counter electromotive force E 0b And the interval time T and the three-phase back electromotive force instantaneous value curve graph are used as a data packet and uploaded to a whole vehicle data center of the electric vehicle for storage. The maintenance of the permanent magnet motor on the electric automobile is facilitated, and data reference is provided for the maintenance of the permanent magnet motor on the electric automobile.
Fig. 2 is an embodiment of the system for monitoring the performance of the driving system of the electric vehicle, which includes a permanent magnet motor.
Referring to fig. 2, the system 200 includes:
the back electromotive force detection unit 201 is used for detecting the no-load back electromotive force u of the permanent magnet motor of the electric automobile on line in each parking or deceleration process of the electric automobile; or for: automatically starting a test task at regular intervals or at preset time intervals Tt, waiting for the electric automobile to stop or decelerate in real time after automatically starting the test task, and detecting the no-load counter electromotive force u of the permanent magnet motor of the electric automobile on line in the process of waiting for the electric automobile to stop or decelerate after waiting for the electric automobile to stop or decelerate;
the performance monitoring unit 202 is configured to monitor performance of a driving system of the electric vehicle according to the idle back electromotive force u detected each time the idle back electromotive force u of the permanent magnet motor of the electric vehicle is detected.
As an exemplary embodiment of the present invention, the performance monitoring unit 202 includes:
the comparison module is used for comparing the current detected no-load back electromotive force u with a preset first no-load back electromotive force threshold T1 and a preset second no-load back electromotive force threshold T2 in real time, wherein T1 is smaller than T2;
the first judgment module is used for judging that the performance of the electric automobile driving system is good when the comparison result of the comparison unit is that u is larger than T2;
the second judgment module is used for judging the performance of the driving system of the electric automobile to slightly decline when the comparison result of the comparison unit is that T1 is more than u and less than or equal to T2, and performing early warning on slight demagnetization of the permanent magnet motor of the electric automobile;
and the third judgment module is used for judging that the performance of the driving system of the electric automobile is seriously reduced when the comparison result of the comparison unit is that u is less than or equal to T1, and carrying out the early warning of the severe demagnetization of the permanent magnet motor of the electric automobile.
As an exemplary embodiment of the present invention, the back electromotive force detection unit 201 is connected to the output end of the stator winding of the permanent magnet motor, and is configured to perform the following steps during each parking of the electric vehicle, respectively:
s1: stopping supplying power to a permanent magnet motor of the electric automobile, and then executing the step S2;
s2: controlling a reverse power generation energy recovery system of the electric automobile to be kept closed, and then executing a step S3;
s3: on-line measurement of signal output frequency f on stator winding side of permanent magnet motor on electric vehicle sh And a corresponding no-load counter-potential E w Simultaneously acquiring the temperature t of a permanent magnet motor on the electric automobile; then step S4 is executed;
s4: according to the rated frequency f of a permanent magnet motor on an electric automobile and the frequency f sh And E w Using the formula
Calculating reference no-load back electromotive force E of permanent magnet motor on electric automobile 0 (ii) a Then step S5 is executed;
s5: according to the temperature t and the reference no-load back electromotive force E 0 Using the formula as E 0b ＝E 0 -(t-tp)×E 0 Xk calculates standard no-load back electromotive force E of permanent magnet motor on electric automobile 0b In the formula, k is a no-load back electromotive force coefficient of the permanent magnet motor, tp is a preset temperature threshold, the value range of tp is 20-25 ℃, and the value range of k is 0.01-0.1%;
s6: obtaining the no-load back electromotive force u, and then recovering power supply to a permanent magnet motor of the electric automobile, wherein u = E 0b 。
As a self-service hairIllustrative embodiment of the invention, the system 200 is directed to measuring the signal output frequency f on the stator winding side of a permanent magnet motor in an electric vehicle sh And a corresponding no-load counter-potential E w The method comprises the following steps:
detecting and recording instantaneous voltage of a stator winding side of a permanent magnet motor on an electric automobile at set time intervals delta t within a preset time period, and generating an instantaneous voltage change curve S by utilizing all recorded instantaneous voltages and respective detection time thereof;
analyzing the instantaneous voltage change curve S, and intercepting a curve segment from the first upper edge zero crossing point to the next upper edge zero crossing point on the instantaneous voltage change curve S, and marking as a target curve segment;
based on the target curve segment, acquiring the instantaneous voltage u corresponding to the first upper edge zero-crossing point 1 And acquiring all instantaneous voltages u on the curve between the two end points of the target curve segment in the recorded instantaneous voltages 2 、u 3 、...、u N-1 And acquiring the next instantaneous voltage u corresponding to the upper edge zero-crossing point corresponding to the next upper edge zero-crossing point N ；
Using expressions
Calculating the signal frequency corresponding to the transient voltage change curve S to obtain the signal output frequency f to be measured sh ；
Based on the above instantaneous voltage u 1 、u 2 、u 3 、...、u N-1 And u N The signal output frequency f is calculated by the following formula (1) or formula (2) sh Corresponding no-load counter-potential E w ：
Wherein, in formula (2): u. u m Is the above instantaneous voltage u 1 、u 2 、u 3 、...、u N-1 And u N Maximum value of-u m Is the above instantaneous voltage u 1 、u 2 、u 3 、...、u N-1 And u N The minimum value of (d).
As an exemplary embodiment of the present invention, the system 200 further comprises:
and the no-load back electromotive force data link curve generating module is configured to utilize the detected no-load back electromotive force in real time to utilize the detected no-load back electromotive force u and the corresponding detection time thereof in real time, and generate and display a no-load back electromotive force data link curve.
As an exemplary embodiment of the present invention, the system 200 further comprises:
a three-phase counter electromotive force instantaneous value graph generating module configured to utilize the detected no-load counter electromotive force u and no-load counter electromotive force E in real time w And reference no-load counter electromotive force E 0 Generating a three-phase back electromotive force instantaneous value curve graph;
the data uploading module is configured to record the interval time T between the current monitoring of the no-load back electromotive force u and the previous monitoring of the no-load back electromotive force u when the no-load back electromotive force u is monitored each time; and is configured to respectively obtain no-load counter electromotive force E when no-load counter electromotive force u is detected w Temperature t of permanent magnet motor and reference no-load counter electromotive force E 0 Standard no-load counter electromotive force E 0b And the interval time T and the three-phase back electromotive force instantaneous value curve graph are used as a data packet and uploaded to a whole vehicle data center of the electric vehicle for storage.
The invention also provides an electric vehicle comprising an electric vehicle body comprising a complete vehicle control center configured to perform the method 100 of the above aspects.
The same and similar parts among the various embodiments in this specification may be referred to each other. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and the relevant points can be referred to the description in the method embodiment.
Although the present invention has been described in detail by referring to the drawings in connection with the preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made on the embodiments of the present invention by those skilled in the art without departing from the spirit and scope of the present invention, and these modifications or substitutions are within the scope of the present invention/any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A performance monitoring method for a driving system of an electric automobile comprises the steps that the driving system comprises a permanent magnet motor; the method for monitoring the performance of the electric automobile driving system is characterized by comprising the following steps:
q1: in the process of stopping or decelerating the electric automobile each time, detecting the no-load back electromotive force u of the permanent magnet motor of the electric automobile on line; or: automatically starting a test task at regular intervals or at preset time intervals Tt, waiting for the electric automobile to stop or decelerate in real time after automatically starting the test task, and detecting the no-load counter electromotive force u of the permanent magnet motor of the electric automobile on line in the process of waiting for the electric automobile to stop or decelerate after waiting for the electric automobile to stop or decelerate;
q2: and when the no-load counter electromotive force u of the permanent magnet motor of the electric automobile is detected every time, monitoring the performance of a driving system of the electric automobile according to the correspondingly detected no-load counter electromotive force u.
2. The method for monitoring the performance of the driving system of the electric automobile according to claim 1, wherein the step Q2 is realized by the following steps:
and comparing the current detected no-load back electromotive force u with a preset first no-load back electromotive force threshold value T1 and a preset second no-load back electromotive force threshold value T2 in real time, wherein T1 is less than T2, and the method comprises the following steps:
when the comparison result is that u is larger than T2, judging that the performance of the driving system of the electric automobile is good;
when the comparison result is that u is more than T1 and less than or equal to T2, judging that the performance of the driving system of the electric automobile is slightly reduced, and performing early warning on slight demagnetization of the permanent magnet motor of the electric automobile;
and when the comparison result is that u is less than or equal to T1, judging that the performance of the driving system of the electric automobile is seriously reduced, and carrying out the early warning of the severe demagnetization of the permanent magnet motor of the electric automobile.
3. The method for monitoring the performance of the driving system of the electric automobile as claimed in claim 2, further comprising the steps of:
when the performance of the driving system of the electric automobile is judged to be slightly reduced and when the performance of the driving system of the electric automobile is judged to be severely reduced, corresponding demagnetization early warnings are fed back to manufacturers and sellers of the electric automobile respectively through the wireless transmission module.
4. The method for monitoring the performance of the driving system of the electric automobile according to claim 1, 2 or 3, wherein in the step Q1, the no-load back electromotive force u of the permanent magnet motor of the electric automobile is detected on line during the parking or deceleration of the electric automobile by:
s1: stopping supplying power to a permanent magnet motor of the electric automobile, and then executing the step S2;
s2: controlling a reverse power generation energy recovery system of the electric automobile to be kept closed, and then executing a step S3;
s3: on-line measurement of signal output frequency f on stator winding side of permanent magnet motor on electric vehicle sh And a corresponding no-load counter-potential E w Simultaneously acquiring the temperature t of a permanent magnet motor on the electric automobile; then step S4 is executed;
s4, according to the rated frequency f of the permanent magnet motor on the electric automobile and f sh And E w By the formula
Calculating reference no-load back electromotive force E of permanent magnet motor on electric automobile 0 (ii) a Then step S5 is executed;
s5, according to the temperature t and the reference no-load back electromotive force E 0 Using the formula as E 0b ＝E 0 -(t-tp)×E 0 Xk calculates standard no-load back electromotive force E of permanent magnet motor on electric automobile 0b In the formula, k is a no-load back electromotive force coefficient of the permanent magnet motor, tp is a preset temperature threshold, and the value range of tp is 20-25 ℃;
s6, obtaining the no-load back electromotive force u, and then restoring power supply to the permanent magnet motor of the electric automobile, wherein u = E 0b 。
5. The method for monitoring the performance of the driving system of the electric automobile according to claim 4, further comprising the steps of:
and generating and displaying a no-load back electromotive force data link curve chart by using the detected no-load back electromotive force u and the corresponding detection time thereof in real time.
6. The method for monitoring the performance of the driving system of the electric automobile according to claim 4, further comprising the steps of:
real-time utilization of detected no-load back electromotive force u, no-load back electromotive force E w And reference to no-load back electromotive force E 0 Generating a three-phase back electromotive force instantaneous value curve graph;
the method for monitoring the performance of the electric automobile driving system further comprises the following steps:
when no-load back electromotive force u is monitored each time, the interval time T between the current monitoring of the no-load back electromotive force u and the previous monitoring of the no-load back electromotive force u is respectively recorded;
when no-load back electromotive force u is monitored each time, the correspondingly obtained no-load back electromotive force E is respectively used w Temperature t of permanent magnet motor and reference no-load counter electromotive force E 0 Standard no-load counter electromotive force E 0b The interval time T and the three-phase back electromotive force instantaneous value curve graph are used as a data packet and uploaded to a whole vehicle data center of the electric vehicle for storage.
7. The utility model provides an electric automobile actuating system performance monitoring system, actuating system includes permanent-magnet machine, its characterized in that, this electric automobile actuating system performance monitoring system includes:
the back electromotive force detection unit is used for detecting the no-load back electromotive force u of the permanent magnet motor of the electric automobile on line in the process of stopping or decelerating the electric automobile each time; or: the system is used for automatically starting a test task at regular intervals or at intervals of a preset time length Tt, waiting for the parking or deceleration of the electric automobile in real time after the test task is automatically started, and detecting the no-load back electromotive force u of the permanent magnet motor of the electric automobile on line in the process of waiting for the parking or deceleration of the electric automobile after waiting for the parking or deceleration of the electric automobile;
and the performance monitoring unit is used for monitoring the performance of the driving system of the electric automobile according to the correspondingly detected no-load back electromotive force u when the no-load back electromotive force u of the permanent magnet motor of the electric automobile is detected every time.
8. The electric vehicle drive system performance monitoring system of claim 7, wherein the performance monitoring unit comprises:
the comparison module is used for comparing the magnitude of the no-load back electromotive force u detected at the current time with a preset first no-load back electromotive force threshold T1 and a preset second no-load back electromotive force threshold T2 in real time, wherein T1 is smaller than T2;
the first judgment module is used for judging that the performance of the electric automobile driving system is good when the comparison result of the comparison unit is that u is larger than T2;
the second judgment module is used for judging the performance of the driving system of the electric automobile to slightly decline when the comparison result of the comparison unit is that T1 is more than u and less than or equal to T2, and performing early warning on slight demagnetization of the permanent magnet motor of the electric automobile;
and the third judgment module is used for judging that the performance of the driving system of the electric automobile is seriously reduced when the comparison result of the comparison unit is that u is less than or equal to T1, and carrying out the early warning of the severe demagnetization of the permanent magnet motor of the electric automobile.
9. The system for monitoring the performance of the driving system of the electric automobile according to claim 7, wherein the back electromotive force detection unit is connected with the output end of the stator winding of the permanent magnet motor, and the back electromotive force detection unit detects the no-load back electromotive force u of the permanent magnet motor of the electric automobile on line in the process of parking or decelerating the electric automobile by the following methods:
s1: stopping supplying power to a permanent magnet motor of the electric automobile, and then executing the step S2;
s2: controlling a reverse power generation energy recovery system of the electric automobile to be kept closed, and then executing a step S3;
s3: on-line measurement of signal output frequency f on stator winding side of permanent magnet motor on electric vehicle sh And a corresponding no-load counter-potential E w Simultaneously acquiring the temperature t of a permanent magnet motor on the electric automobile; then step S4 is executed;
s4, according to the rated frequency f of the permanent magnet motor on the electric automobile and f sh And E w Using the formula
Calculating reference no-load counter electromotive force E of permanent magnet motor on electric automobile 0 (ii) a Then step S5 is executed;
s5, according to the temperature t and the reference no-load back electromotive force E 0 Using the formula as E 0b ＝E 0 -(t-tp)×E 0 Standard no-load back electromotive force E of permanent magnet motor on Xk calculation electric automobile 0b In the formula, k is a no-load back electromotive force coefficient of the permanent magnet motor, tp is a preset temperature threshold, and the value range of tp is 20-25 ℃;
s6, obtaining the no-load back electromotive force u, and then restoring power supply to the permanent magnet motor of the electric automobile, wherein u = E 0b 。
10. An electric vehicle comprising an electric vehicle body comprising a vehicle control center, wherein the vehicle control center is configured to perform the method of any of claims 1-6.
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