Current gain diagnosis method, computer storage medium, device and controller

Abstract

The invention belongs to the technical field of power electronics, and particularly relates to a current gain diagnosis method, a computer storage medium, a device and a controller. A first bias judgment step / unit approves a bias value of a current sensor (002) to be judged to ensure a precondition of a processing process, and a second fault diagnosis step / unit compares a current measured value with a value of an injection current (059) after data conversion under a static working condition. A phase current gain correction sequence (080) is obtained, and a UVW phase diagnosis indication switching value (010) can be obtained according to a preset precision coefficient (019) A, so that quantitative diagnosis of a current gain G (Gain) fault is realized; if necessary, the corrected current sequence (090) can be used for replacing the actually measured signal for current closed-loop control; according to the method and the product, the fault diagnosis coverage rate of the current sensor of the electric driving system under the static working condition can be improved, the complicated maintenance process can be replaced by software upgrading under the existing hardware structure, and the reliability and the safe operation level of the electric control system are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power electronics, and particularly relates to a current gain diagnosis method, a computer storage medium, a device and a controller. Background Art

[0002] The detection of current is a necessary link in the closed-loop control process of many motors. When a current sensor as shown Figure 1 fails, in order to avoid the spread of faults or for safety reasons, a shutdown mechanism is usually triggered, which will lead to the paralysis or loss of function of the motor drive system. Among them, for a system with a multi-phase armature structure, the failure of single-phase current detection has a relatively higher proportion or probability compared with the failure of two-phase, multi-phase or even all current detections, which also becomes the key scenario concerned by this solution.

[0003] When the related technology diagnoses the current ratio fault of the current sensor, that is, the fault of the gain G (Gain), it usually adopts an indirect diagnosis method; that is, by diagnosing related faults, the fault of the gain G is indirectly reflected. For example, it can be based on the diagnosis of multi-phase (such as three-phase) current where the sum of currents according to Kirchhoff's law is zero, or the diagnosis method of the balance of phase current amplitudes, etc. However, these diagnoses require the electric drive system to be in an operating state and cannot be implemented for a static system. At the same time, the fault diagnosis of the motor in the driving operation state will be accompanied by the abnormal operation process of the system, which will lead to safety risks in the system and this also needs to be极力 avoided.

[0004] In addition, as shown Figure 2 in the phenomenon of gain upshift 007 or gain downshift 009, the actual current values collected at time x are A1 and A3; compared with the ideal value, their magnitude relationship is: A1 < A2 < A3; when the current increases, the current deviation caused by the gain G upshift or downshift is greater; this phenomenon can also be indirectly reflected only during the process of starting and running the electric drive system by relying on the above diagnosis process. At the same time, it is difficult to clearly and correctly distinguish the fault of the current sensor gain G from other faults.

[0005] Considering the lack of a diagnosis scheme for the failure of the current sensor G gain in the static state, when the current sensor gain G suddenly fails or gradually fails due to aging factors, the static electric drive system may not be able to perceive this failure state. For example, in the diagnosis of the sum of three-phase currents not being 0 or the diagnosis of unequal phase current amplitudes, it can only be realized during the operation of the electric drive system. For an electric drive system with two current sensors, it is even impossible to use the diagnosis mechanism of the sum of three-phase currents being 0. Therefore, the failure diagnosis mechanism of the current sensor gain G in the static electric drive system urgently needs to be improved. In addition, it is also necessary to timely correct the parameters of the failure of the current sensor gain G to meet the needs of the subsequent normal operation of the electric drive system. Summary of the Invention

[0006] An embodiment of the present invention discloses a current gain diagnosis method, the core process of which includes a first bias judgment step and a second fault diagnosis step; the first bias judgment step obtains a first bias value sequence of the motor current gain, if the elements of the first bias value sequence belong to a preset bias allowable interval, the second fault diagnosis step is allowed to be executed; otherwise, the current processing is terminated.

[0007] Specifically, its second fault diagnosis step is that when the first set of given currents i*d and i*q of the motor vector control d-axis and q-axis are all 0, an injection current ic is applied to its d-axis and the injection current is converted into a three-phase current; then, the deviation between the three-phase current and the actual current collection value is compared to obtain a gain correction coefficient; at the same time, if the gain correction coefficient falls within the preset value range, it is considered that the current gain indicator is normal.

[0008] In addition, if the motor is a three-phase AC motor and is used to drive a vehicle and the vehicle is in a free state of the wheel system, that is, FW mode; then its first offset value sequence can be calculated from the current gain sequence Gn to be diagnosed; wherein, the vehicle is in a stationary state in FW mode.

[0009] Specifically, the second fault diagnosis step may also include a process of converting the injected current into a second group of given currents i*α and i*β corresponding to the αβ axis coordinates according to a second reverse operation of the angle θ between the d axis and the axis of the phase to be processed; and converting the second group of given currents into a current sensor sequence and / or a given current comparison sequence corresponding to the first group of given currents according to the first reverse operation, and the αβ axis corresponds to the two-phase stationary coordinate system.

[0010] The current sensor sequence may include at least one current sensor to be determined; the current sensor sequence may be used to provide a current closed-loop measured current sequence to the electric drive control system.

[0011] Furthermore, the motor may have at least two phases provided with current sensors; wherein, the step of comparing the deviations between the three-phase currents and the actual current collection values ​​to obtain the gain correction coefficients includes: obtaining the phase current gain sequence by comparing the differences between the elements of the given current reference sequence and the measured current sequence and the corresponding elements of the first offset value sequence On.

[0012] Furthermore, the current gain diagnostic method may also be provided with a third gain correction step; and a confidence interval Ab (1-A, 1+A) is obtained according to a preset sensor accuracy threshold A, wherein: A is less than 0.1 or A is equal to a preset experimental calibration value; if the gain correction coefficient of the phase current to be detected falls within the confidence interval Ab, it is considered that the gain of the phase to be evaluated is normal; otherwise, the actual current is corrected to obtain a corrected current sequence.

[0013] The corrected current sequence can be calculated from the phase current gain sequence, the measured current sequence and the first offset value sequence according to the following formula:

[0014] Specifically, the current gain diagnostic method can be used for permanent magnet synchronous motor (PMSM) current loop fault diagnosis; if the gain of one phase to be evaluated is abnormal, the measured current sequence can be replaced by a corrected current sequence to provide current parameters to the electric drive control system, the preset control system and / or the controller.

[0015] Among them, the corrected current sequence can be converted into an αβ static current vector by forward operation to realize motor vector control; its forward operation can adopt the Clarke transformation process.

[0016] Correspondingly, an embodiment of the present invention further discloses a computer storage medium, including a storage medium body for storing a computer program; when the computer program is executed or called by a microprocessor, any of the above current gain diagnostic methods can be implemented.

[0017] Similarly, an embodiment of the present invention further discloses a current gain diagnosis correction device, which can also be used to implement any of the above current gain diagnosis methods; its core includes a current sensor sequence and a phase current gain observer.

[0018] The phase current gain observer includes a first conversion module, a third conversion module, a phase current gain calculation module, and a phase current gain diagnosis module; the first conversion module is used to convert the given currents of the d and q axes and the injected d-axis current ic into given currents i*α and i*β in the αβ phase coordinate system; the third conversion module is used to convert the given current i * α and i * β Converted into the given current i of the three phases U, V, and W * u 、i * v 、i * w The phase current gain calculation module is used to calculate the phase current gain correction coefficient, and calculate the corrected phase current i' according to the current gain correction coefficient u 、i' v 、i' w The phase current gain diagnosis module is used to determine whether the phase current gain is normal according to the phase current gain correction coefficient, and output the gain status diagnosis indication result.

[0019] In addition, an embodiment of the present invention further discloses a controller, including the above current gain diagnosis and correction device and / or computer storage medium, which can be used to solve the same technical problem.

[0020] In summary, the present invention can verify the bias value of the current sensor to be determined through the first bias judgment step / unit to ensure the prerequisite of the processing process, and the second fault diagnosis step / unit compares the actual current value with the value of the injected current after data conversion under static conditions to obtain the phase current gain correction sequence and obtain the UVW phase diagnosis indication switch value according to the preset accuracy coefficient A, thereby realizing the quantitative diagnosis of the current gain G (Gain) fault.

[0021] If necessary, the corrected current sequence can be used instead of the measured signal for current closed-loop control; the method and product can improve the coverage of current sensor fault diagnosis in the electric drive system under static conditions, and can replace the complicated maintenance process with software upgrade under the existing hardware structure, thereby improving the reliability and safe operation level of the electronic control system.

[0022] It should be noted that the terms "first", "second" and similar terms used in this article are only for describing the various components in the technical solution, and do not constitute a limitation of the technical solution, nor can they be understood as an indication or suggestion of the importance of the corresponding elements; elements with "first", "second" and similar terms indicate that the corresponding technical solution contains at least one of the element. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the present invention and facilitate further understanding of the technical effects, technical features and purposes of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings. The accompanying drawings constitute an essential part of the specification and are used together with the embodiments of the present invention to illustrate the technical solution of the present invention, but do not constitute a limitation to the present invention.

[0024] The same reference numerals in the accompanying drawings represent the same components, specifically: Figure 1 This is a schematic diagram of the Hall current sensor HCS sampling.

[0025] Figure 2 Schematic diagram of gain deviation GE diagnosis failure in static state.

[0026] Figure 3 The timing relationship diagram of the diagnostic process of the embodiment of the present invention is shown in FIG. Figure 1 .

[0027] Figure 4 It is a block diagram of the structural relationship between the embodiment of the present invention and the electric drive control system.

[0028] Figure 5 It is a schematic diagram of the rotating coordinate system from UVW three-phase to αβ two-phase and then to dq two-phase according to an embodiment of the present invention.

[0029] Figure 6This is a conversion of the current given value from the two-phase rotating dq axis to the two-phase stationary αβ phase coordinate system in the embodiment of the present invention.

[0030] Figure 7 It is another form of the current given value from the dq axis of two-phase rotation to the αβ phase coordinate system of two-phase stationary in the embodiment of the present invention.

[0031] Figure 8 It is a given vector of UVW current in the embodiment of the present invention.

[0032] Fig. 9 is the phase current gain of the embodiment of the present invention.

[0033] Fig.10 It is the UVW phase current after gain correction in the embodiment of the present invention.

[0034] Fig.11 It is the Clarke transformation expression from the three-phase stationary coordinate system to the two-phase stationary coordinate system in the embodiment of the present invention.

[0035] Fig.12 It is the UVW phase diagnosis indicating switch quantity of the embodiment of the present invention.

[0036] Fig.13 It is a schematic diagram of the phase current gain correction and status diagnosis process according to an embodiment of the present invention.

[0037] Fig.14 This is one of the verification diagrams when the gain is unchanged according to the embodiment of the present invention.

[0038] Fig.15 This is the second verification diagram when the gain of the embodiment of the present invention remains unchanged.

[0039] Fig.16 This is an example of solving the gain correction coefficient in an embodiment of the present invention.

[0040] Fig.17 This is one of the comparison verification diagrams when the gain is amplified by 150% in an embodiment of the present invention.

[0041] Fig.18 This is the second comparison verification diagram when the gain is amplified by 150% according to the embodiment of the present invention.

[0042] Fig.19 The figure is a schematic diagram of a flow chart of an embodiment of the method of the present invention.

[0043] Fig. 20 The composition structure of the product of the present invention is shown in FIG. Figure 1 .

[0044] Fig.21 The composition structure of the product of the present invention is shown in FIG. Figure 2 .

[0045] Fig. 22 The composition structure of the product of the present invention is shown in FIG. Figure 3 .

[0046] in: 001-current to be detected, such as phase current Ip; 002-current sensor; 003-Detection unit output (voltage), such as Vout; 005-Gain deviation ideal value; 006-Gain Error, i.e. GE (Gain Error); 007-Gain upward deviation, i.e. GainErrMax; 009-Gain down deviation, i.e. GainErrMin; 010-UVW phase diagnosis indication switch quantity; 011-U phase state indication switch quantity, i.e. Fu; 012-V phase state indication switch quantity, i.e. Fv; 013-W phase state indication switch quantity, i.e. Fw; 019-Accuracy coefficient, i.e. A; 020-αβ static current vector; 021-α static current, i.e. iα; 022-β static current, iβ; 030-Measured current sequence, such as the measured current sequence (iu, iv, iw) 031-U phase actual collected current value, i.e. iu; 032-The actual current value collected on the V phase (not shown in the figure), i.e., iv; 033-W phase actual collected current value, i.e. iw; 040-first bias value sequence, i.e. On; 041-U phase current sensor bias value, i.e. Ou; 042-V phase current sensor bias value (not shown in the figure), i.e. Ov; 043-W phase current sensor bias value, i.e. Ow; 049-bias tolerance interval, if the difference between the bias value and 0 is less than the first tolerance threshold Ot; 050-the second set of given currents, such as αβ given current vectors; 051-α axis current given value, i.e. i*α; 052-β axis current given value, i.e. i*β; 054-the first set of given currents, such as dq given current vectors; 055-d axis current given value, i.e. i*d; 057-q axis current given value, i.e. i*q; 059- (d-axis) injection current, i.e. ic; 060-axis angle, that is, the angle between the d-axis of the synchronous rotating coordinate system and the axis of the phase to be processed (such as U phase), that is, the motor rotor angle θ from the position sensor PS (Position Sensor); 061-Park inverse transform; 063-Clarke inverse transformation; 065-Clarke Transformation 070-given current comparison sequence, such as given current [i*u,i*v,i*w] in UVW phase coordinate system; 071-U phase current given value, i.e. i*u; 072-V phase current given value (marked in the figure), i*v; 073-W phase current given value, i.e. i*w; 080-phase current gain correction sequence (correction coefficient vector), i.e. G*p; 081-U phase correction coefficient, i.e. G*u; 082-V phase correction factor (marked in the figure), i.e. G*v; 083-W phase correction coefficient, i.e. G*w; 089-Current gain sequence, i.e. Gn 090-corrected current sequence; 091-U phase corrected current, i.e. I`u; 092-V phase corrected current, i.e. I'v; 093-W phase corrected current, i.e. I'w; 100-first bias determination step; 110 - current sensor sequence, i.e. Hn; 111-SU, i.e., the first phase current sensor; 112-SV, i.e., the second phase current sensor; 113-SW, the third phase current sensor; 199-position sensor, i.e. PS; 200-second fault diagnosis step; 210-first conversion step; 220-second conversion step; 230-Third Amendment Step; 300-third gain correction step; 310-Phase current gain processing and diagnostic steps; 600-Current gain diagnostic correction device; 611-first conversion module; 613-third conversion module; 615-phase current gain calculation module; 617-phase current gain diagnostic module; 666-Rotation coordinate system example; 900 - Vehicles; 901-controller; 903-Computer storage media; 999-Motor. DETAILED DESCRIPTION

[0047] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. Of course, the specific embodiments described below are only for explaining the technical solutions of the present invention, rather than for limiting the present invention. In addition, the parts described in the embodiments or the accompanying drawings are only examples of the relevant parts of the present invention, rather than the whole of the present invention.

[0048] like Fig.19 The current gain diagnosis method shown includes a first bias judgment step 100 and a second fault diagnosis step 200; the first bias judgment step 100 obtains the first bias value sequence 040 of the current gain of the motor 999. If the element of the first bias value sequence 040 belongs to the preset bias allowable interval 049, the second fault diagnosis step 200 is allowed to be executed; otherwise, the current processing is terminated; the second fault diagnosis step 200 applies an injection current ic to the d-axis and converts the injection current into a three-phase current when the first group of given currents i*d and i*q of the d-axis and q-axis of the vector control of the motor 999 are both 0; compares the deviation between the three-phase current and the actual current acquisition value to obtain the gain correction coefficient; if the gain correction coefficient falls within the preset value range, the current gain indicator is considered to be normal.

[0049] Among them, the motor 999 can adopt a three-phase AC motor and is used to drive the vehicle 900, and the vehicle 900 is in a free state of the wheel system, that is, FW mode; the vehicle 900 is stationary in the FW mode; the first bias value sequence 040 can be calculated from the current gain sequence Gn to be diagnosed.

[0050] Furthermore, its second fault diagnosis step 200 can convert the injected current 059 into a second group of given currents 050, i.e., i*α and i*β, corresponding to the αβ axis coordinates according to a second reverse operation of the angle 060, i.e., θ, between the d axis and the axis of the phase to be processed; and can convert the second group of given currents 050 into a given current comparison sequence 070 corresponding to the current sensor sequence 110 and / or the first group of given currents 054 according to the first reverse operation, wherein the αβ axes correspond to the two-phase stationary coordinate system.

[0051] Specifically, the current sensor sequence 110 may include at least one current sensor 002 to be determined; the current sensor sequence 110 may be used to provide a current closed-loop measured current sequence 030 to the electric drive control system.

[0052] Among them, the motor 999 is provided with current sensors on at least two phases; the step of comparing the deviations between the three-phase currents and the actual current acquisition values ​​to obtain the gain correction coefficients includes: obtaining the phase current gain sequence 080 by comparing the difference between the elements of the given current reference sequence 070 and the measured current sequence 030 and the corresponding elements of the first bias value sequence 040.

[0053] Furthermore, the current gain diagnostic method may also be provided with a third gain correction step 300; a confidence interval Ab (1-A, 1+A) is obtained according to a preset sensor accuracy threshold A, wherein: A is less than 0.1 or A is equal to a preset experimental calibration value; if the gain correction coefficient of the phase current to be detected falls within the confidence interval Ab, it is considered that the gain of the phase to be evaluated is normal; otherwise, the actual current is corrected to obtain a corrected current sequence 090.

[0054] The corrected current sequence 090 can be calculated from the phase current gain sequence 080, the measured current sequence 030 and the first offset value sequence 040 according to the following formula:

[0055] Furthermore, the current gain diagnostic method can be used for permanent magnet synchronous motor PMSM current loop fault diagnosis; wherein, if the gain of one phase to be evaluated is abnormal, the corrected current sequence 090 can be used to replace the measured current sequence 030 to provide current parameters to the electric drive control system, the preset control system and / or the controller 901.

[0056] Among them, the corrected current sequence 090 can be converted into an αβ static current vector 020 by forward operation to realize motor vector control; its forward operation includes a Clarke transformation 065 process.

[0057] Furthermore, if Fig. 20 , 22 The computer storage medium 903 shown includes a storage medium body for storing a computer program; when the computer program is executed or called by a microprocessor, any of the above current gain diagnostic methods can be implemented.

[0058] Similarly, if Figure 4 The current gain diagnosis correction device 600 shown can also be used to implement any of the current gain diagnosis methods as above; it includes a current sensor sequence and a phase current gain observer; wherein: the phase current gain observer includes a first conversion module 611, a third conversion module 613, a phase current gain calculation module 615, and a phase current gain diagnosis module 617.

[0059] Specifically, the first conversion module 611 is used to convert the given currents of the d and q axes and the injected d-axis current ic into given currents i*α and i*β in the αβ phase coordinate system; the third conversion module 613 is used to convert the given current i * α and i * β Converted into the given current i of the three phases U, V, and W * u 、i * v 、i * w Phase current gain calculation module 615 is used to calculate the phase current gain correction coefficient, and calculates the corrected phase current i' according to the phase current gain correction coefficient u 、i' v 、i' w The phase current gain diagnosis module 617 is used to determine whether the phase current gain is normal according to the phase current gain correction coefficient, and output the gain state diagnosis indication result.

[0060] Similarly, if Fig. 20 , 21 The controller 901 shown in FIG. 22 includes the current gain diagnosis and correction device 600 and / or the computer storage medium 903 as described above, which can also be used to solve the diagnosis and compensation (or correction) of the current sensor G gain when the vehicle 900 is in a static state.

[0061] In practical applications, in order to perform gain diagnosis and correction of the phase current sensor of the vehicle electric drive system under static conditions, it can be achieved by setting a phase current gain observer. For details, please refer to the following two solutions.

[0062] Solution 1: When the vehicle is static, such as under 0Nm control before starting, a certain current can be injected into the d-axis of the electric drive system; by comparing the actually measured phase current with the phase current converted from the injected given current, it can be determined whether there is an abnormal deviation in the actually measured current; then, the phase current gain can be corrected; for example, the actually collected three-phase current can be corrected, and the corrected three-phase current can be used for coordinate transformation of current closed-loop control.

[0063] Solution 2: The correction coefficient calculated for the phase current gain can be diagnosed. If the correction coefficient exceeds the default range, it is considered that the corresponding phase gain state in the three-phase UVW is abnormal, and corresponding indication information can be given.

[0064] The use of the method and product corresponding to the embodiment of the present invention can improve the coverage of the current sensor fault diagnosis of the electric drive system, that is, the failure diagnosis of the phase current sensor gain when the vehicle is static; further, it is beneficial to improve the safety protection capability of the system.

[0065] It should be noted that in order to avoid the influence of the inaccurate current sensor bias value on the phase current gain observer, before the phase current gain observer is turned on, the current sensor bias value verification must be completed first; when the judgment result proves that the bias value is within the normal range, the phase current gain observer can be turned on; otherwise, if the bias value is within the abnormal range, the phase current gain observer will not be turned on.

[0066] like Figure 3 As shown, the current sensor bias value can be verified in the FW mode, i.e., the first bias judgment step 100; wherein, the current can be collected under zero current, and if the collected current is not zero, it is considered that the bias value given by the current sensor does not meet the requirements; further, if the bias value of the current sensor meets the requirements, the subsequent phase current gain calculation process can be started, i.e., the corresponding processing process of the second fault diagnosis step 200.

[0067] Furthermore, if Figure 4 The block diagram of the structural relationship between the embodiment of the present invention and the electric drive control system shown in the figure gives the information flow and core signal set of the above-mentioned phase current gain observer and related systems in actual application scenarios; among them, the phase current gain observer of the vehicle single current sensor electric drive system, that is, the fault diagnosis and correction device 600 in the figure, the above-mentioned phase current gain observer.

[0068] Specifically, the fault diagnosis and correction device 600 can be used for vector control of a permanent magnet synchronous motor; the fault diagnosis and correction device 600 includes a first signal processing module 621, a third signal processing module 623, a fifth signal processing module 625 and a seventh signal processing module; wherein the first signal processing module 621 can convert the dq axis given and d axis injected current ic and the angle θ into a given current, that is, a second set of given currents αβ; the angle θ can be obtained by collecting the motor rotor angle by the position sensor PS (Position Sensor).

[0069] Furthermore, the third signal processing module 623 converts the αβ axis given current into a three-phase UVW given current; and the fifth signal processing module 625 can calculate the phase current gain, compare the given current output by the third signal processing module 623 with the actually collected phase current, so as to obtain the phase current gain correction coefficient and the corrected phase current; wherein, the seventh signal processing module 627 performs phase current gain diagnosis on the phase current gain correction coefficient output by the fifth signal processing module 625, and obtains a diagnostic conclusion on the gain fault of each phase current sensor.

[0070] Specifically, the UVW three-phase to αβ two-phase coordinate system and then to the dq two-phase rotating coordinate system can be used as follows Figure 5The coordinate transformation process shown in the figure; among them, the Clark coordinate transformation realizes the 3s / 2s transformation process as shown in the figure; and the αβ two-phase coordinate system to the dq two-phase rotating coordinate system can be realized by Park transformation, that is, 2s / 2r process; it can be assumed that the stator U-phase axis coincides with the transformed α-phase axis; then the angle between the rotating d-axis and the U-phase is θ.

[0071] Furthermore, the improved design of the fault diagnosis and correction device of the embodiment of the present invention includes the following steps.

[0072] like Figure 6 As shown, the first signal processing module 621 converts the given current of the dq axis (i.e., i*d and i*q) and the injected current ic of the d axis and the angle θ into the given current of αβ; wherein the current given value based on the αβ phase coordinate system can be obtained according to the given value of the dq axis of the electric drive control system through the following steps: Figure 6 The Park inverse transform is obtained (i.e., 2r / 2s); that is, the dq axis of the two-phase rotation is converted to the αβ phase coordinate system of the two-phase stationary.

[0073] Specifically, the following was established: Figure 6 The relationship between the second group of given currents 050, i.e., αβ, and the first group of given currents 054, i.e., dq given current vectors is shown; including the α-axis current given value 051, i.e., i*α, and the β-axis current given value 052, i.e., i*β, as well as the d-axis current given value 055, i.e., i*d, and the q-axis current given value 057, i.e., i*q, and also includes the d-axis injected current ic and the angle θ between the d-axis and the U-phase axis of the synchronous rotating coordinate system; and as mentioned above, the angle θ can be obtained by collecting the motor rotor angle by the position sensor PS.

[0074] When implementing the method of the present invention, the following may be used: Figure 6 The given values ​​of the dq axis currents i*d and i*q shown are both equal to 0; and the injection current ic of the d axis is kept at a preset calibration value, such as -100A selected in this embodiment; for different electric drive systems, ic can be recalibrated; based on this, the following can be obtained: Figure 7 The process shown is from the injected current ic to the second set of given current 050.

[0075] Furthermore, if Figure 8 As shown, the αβ axis given current, ie, the second set of given currents 050 , can be converted into three-phase UVW given currents, ie, the given current comparison sequence 070 , by the third signal processing module 623 .

[0076] Specifically, the current given value of the three-phase UVW phase coordinate system can be obtained by Clarke inverse transformation according to the given value of the αβ axis of the electric drive control system (2s / 3s). The current given value of the two-phase stationary αβ axis to the three-phase stationary UVW phase coordinate system is as follows: Figure 8 The transformation process is shown.

[0077] Among them, i*u, i*v and i*w are the current given values ​​of the three-phase UVW, that is, the specific values ​​of the given current reference sequence 070; so far, combined with the aforementioned transformation process, the given current reference sequence 070 can be obtained through the first group of given currents 054, namely i*d and i*q, that is, the dq axis current given values.

[0078] Furthermore, the fifth signal processing module 625 may perform phase current gain calculation, and thus obtain a phase current gain correction coefficient and a corrected phase current.

[0079] It should also be noted that before calculating the phase current gain, the phase current verification operation corresponding to the first bias judgment module 610 or the first bias judgment step 100 needs to be completed; if the bias value is found to be inconsistent during the bias verification process, the other processing processes will fail; at this point, the phase current gain can be calculated by Fig. 9 The process shown is used to obtain the phase current gain correction sequence 080 (correction coefficient vector), namely G*p.

[0080] Among them, iu, iv and iw are the actual current values ​​collected by the three-phase UVW, Ou, Ov and Ow are the pre-calibrated phase current sensor bias values; G*u, G*v and G*w are the correction coefficients of each phase derived from the phase current gain; at this time, the correction coefficient can be used to correct the gain of the phase current sensor.

[0081] Specifically, the U-phase corrected current 091 is I'u; the V-phase corrected current 092 is I'v; the W-phase corrected current 093 is the result of the actual collected current values ​​of the three-phase UVW after gain correction; Fig.10 , Figure 4 As shown, the correction value, i.e., the corrected current sequence 090, can also be sent to the 3s / 2s coordinate transformation module for current closed-loop control.

[0082] The transformation of the permanent magnet synchronous motor from the three-phase stationary coordinate system to the two-phase stationary coordinate system is called Clarke transformation, where the expression is as follows: Fig.11 shown.

[0083] Furthermore, the phase current gain fault state can be evaluated and the diagnosis conclusion can be output to the relevant unit for reminder or intervention.

[0084] Specifically, the phase current gain diagnosis can be based on Figure 4 The correction coefficient calculated by the actual phase current gain of the output is used for judgment; Fig.12As shown, when the U-phase correction coefficient 081, that is, G*u is greater than 1-A and less than 1+A at the same time, it is considered that the U-phase current gain is normal, or that the U-phase state indication switch quantity 011, that is, Fu=1; therefore, the actually collected phase current iu can be selected for the 3s / 2s coordinate transformation of the electric drive system, and then for the current closed-loop control; that is, the original calibrated gain Gu of the current sensor is maintained unchanged; on the contrary, when G*u is not in the above interval, that is, it does not fall into the preset bias allowable interval 049, it is considered that the U-phase current gain is abnormal, Fu=0; at this time, the U-phase corrected current 091, that is, I`u can be selected for the 3s / 2s coordinate transformation of the electric drive system, and then for the above-mentioned current closed-loop control process; in addition, if the U or V phase is involved, the method and process are similar and no further description is required.

[0085] Among them, Fu, Fv and Fw are the phase components of the UVW phase diagnosis indication switch quantity 010; if the component of a phase is equal to 0, it is considered that the gain of the corresponding phase is abnormal; conversely, if any phase of Fu, Fv and Fw is equal to 1, it is considered that the corresponding phase is normal.

[0086] Specifically, the above A value, i.e., the accuracy coefficient 0.10, can be adjusted according to the actual characteristics of the electric drive system. In the present embodiment, it is selected based on the accuracy of 3% of the current sensor of the electric drive system, i.e., A is 3% or 0.03.

[0087] Among them, the following can be used Fig.13 The phase current gain correction and status diagnosis process shown in the figure performs phase current gain correction calculation; then, the phase current gain status diagnosis result and corresponding intermediate data can be obtained.

[0088] It should be noted that the current gain processing and diagnosis process of this example is implemented in a static scenario where the controlled system is in a static state; when the phase current sensor gain is abnormal, the phase current gain observer in this embodiment can be used to calculate the gain correction coefficient of the phase current sensor of the vehicle electric drive system, and further obtain diagnostic information of the phase current gain status.

[0089] In addition, the above process is only a specific implementation method of the present invention and cannot be understood as the entire technical solution of the present invention; it should be pointed out that for ordinary technicians in this field, modifications and improvements without departing from the technical concept of the present invention will also fall within the scope of protection of the present invention.

[0090] Compared with the related art, the method and product of the present invention can improve and diagnose faults in an electric drive control system that uses a current sensor for current detection without adding additional hardware; the inventive concept is also applicable to electric drive control systems with different line topologies, such as electric drive control systems that use two or a single current sensor.

[0091] In addition, the method and product of the present invention can implement relevant processing processes in a static state without the need to rely on three-phase symmetry mechanisms or phase current amplitude and other characteristics for diagnosis or processing; its phase current gain observer can make up for the shortcomings of related systems in the field of diagnostic mechanisms in a static state.

[0092] Specifically, Figure 14-18 Experimental data are given, and the above judgment is further confirmed; among them, the given speed of the electric drive system is 0rpm (i.e. static); its given motor torque is also 0Nm, and the given dq-axis current is still 0A; when the given d-axis injection current ic is -100A, the bus voltage is 350V, and the angle θ between the d-axis and the U-phase axis of the synchronous rotating coordinate system is also given as 0°, the output of its phase information is as follows.

[0093] like Fig.14 , 15 As shown, the actual current gain of the three-phase UVW remains unchanged, that is, U / V / W-Gain = 100%. Fig.14 It can be found that after the current ic (-100A) is injected into the d-axis of the electric drive system, the actual d-axis current is -100A, the d-axis current is 0A, the torque is 0Nm, the U-phase current is -141A, and the V-phase and W-phase currents are 70.5A.

[0094] Fig. 9 and Fig.10 To implement the verification comparison waveform of the present invention, the three-phase uvw actual current Gain gain is amplified by 150%, that is, U-Gain = 150%, V / W-Gain = 100%. It can be concluded from the figure that when the electric drive system d-axis current ic injects a current of -100A, the actual d-axis current is -112A, the q-axis current is 21.6A, the torque is 0Nm, the U-phase current sensor current is -160A, the V-phase current sensor current and the W-phase current sensor current are both 53A, the U-phase actual current is -106A, and the V-phase actual current and the W-phase actual current are 53A.

[0095] Further, the gain correction coefficient of the phase current sensor can be processed; wherein, compared with Fig.15 and Fig.18 It can be seen that when the gain coefficient of the U-phase current sensor is amplified by 150% compared with the normal gain coefficient, that is, U-Gain = 150%, the gain coefficient of the phase current sensor can be used as follows Fig.16 method to solve it.

[0096] Among them, the U phase correction coefficient is 081, that is, G*u=0.625.

[0097] Furthermore, its gain state can also be diagnosed; on the one hand, the gain correction coefficients of the phase current sensors can be compared; among them, Fu, Fv, and Fw are the diagnosis indication digital quantities 010 of the UVW phases; its characteristic inequality, that is, 1 - A < G*u < 1 + A, can be used for specific discrimination; the value of A can also be adjusted according to the actual characteristics of the electric drive system.

[0098] Specifically, as in Figure 14-18 the embodiment of, calibration was carried out according to the accuracy of the current sensor of the electric drive system, which is 3%; obviously, when the gain coefficient of the U-phase current sensor is magnified by 150% compared with the normal gain coefficient, the gain correction coefficient G*u of the U-phase current is less than 1 - A; at this time, it can be considered that the U-phase current gain is abnormal and Fu = 0.

[0099] As mentioned above, the method and product of the present invention are applicable to electric drive control systems based on three-phase, two-phase, and single-phase current sensors, and the electric drive control system can be extended with reference to the results of Figure 4 ; when conforming to the concept of the present invention, the current gain processing process of electric drive systems with other topological structures will also fall within the scope of the structural method and / or product as shown in Figures 19 to 22 .

[0100] It should be noted that the above embodiments are only for more clearly illustrating the technical solutions of the present invention. Those skilled in the art can understand that the implementation manners of the present invention are not limited to the above content. Obvious changes, substitutions, or replacements based on the above content do not exceed the scope covered by the technical solutions of the present invention; without departing from the concept of the present invention, other implementation manners will also fall within the scope of the present invention.

Claims

1. A current gain diagnostic method for current sensor fault diagnosis and treatment; characterized in that The method comprises a first bias judgment step (100) and a second fault diagnosis step (200); the first bias judgment step (100) obtains a first bias value sequence (040) of a current gain of a motor (999); if an element of the first bias value sequence (040) belongs to a preset bias tolerance interval (049), the second fault diagnosis step (200) is allowed to be executed; otherwise, the current processing is terminated; the second fault diagnosis step (200) applies an injection current (059) ic to the d-axis and the q-axis when the first set of given currents (054) i*d and i*q of the motor (999) vector control d-axis and q-axis are both 0, and converts the injection current (059) into a three-phase current; compares the deviation between the three-phase current and the actual current acquisition value to obtain a gain correction coefficient; if the gain correction coefficient falls within the preset value range, the current gain index is considered to be normal.

2. The current gain diagnostic method according to claim 1, wherein: The motor (999) is a three-phase AC motor, the motor (999) is used to drive a vehicle (900), and the vehicle (900) is in a gear train free state, i.e., a FW mode; the vehicle (900) is stationary in the FW mode; and the first offset value sequence (040) is derived from a current gain sequence (089) Gn to be diagnosed.

3. The current gain diagnostic method according to claim 1 or 2, wherein: The second fault diagnosis step (200) comprises converting the injected current (059) into a second group of given currents (050) i*α (051) and i*β (052) corresponding to αβ axis coordinates according to a second reverse operation of an angle (060) θ between the d axis and the axis of the phase to be processed; and converting the second group of given currents (050) into a given current comparison sequence (070) corresponding to the current sensor sequence (110) and / or the first group of given currents (054) according to a first reverse operation, the αβ axes corresponding to a two-phase stationary coordinate system.

4. The current gain diagnostic method according to claim 3, wherein: The current sensor sequence (110) comprises at least one current sensor to be determined (002); the current sensor sequence (110) is used to provide a current closed-loop measured current sequence (030) to the electric drive control system.

5. The current gain diagnostic method according to claim 2 or 4, wherein: The motor (999) is provided with current sensors on at least two phases; and the step of comparing the deviations between the three-phase currents and actual current acquisition values ​​to obtain the gain correction coefficients comprises: obtaining a phase current gain sequence (080) by comparing the ratios of the differences between the respective elements of the given current reference sequence (070) and the measured current sequence (030) and the corresponding elements of the first offset value sequence (040) On.

6. The current gain diagnostic method according to claim 5, further comprising a third gain correction step (300); obtaining a confidence interval Ab (1-A, 1+A) according to a preset sensor accuracy threshold A, wherein: A is less than 0.1 or A is equal to the preset experimental calibration value; If the gain correction coefficient of the phase current to be detected falls within the confidence interval Ab, it is considered that the gain of the phase to be evaluated is normal; otherwise, the actual current is corrected to obtain a corrected current sequence (090).

7. The current gain diagnostic method according to claim 6, wherein: The corrected current sequence (090) is calculated from the phase current gain sequence (080), the measured current sequence (030) and the first offset value sequence (040) according to the following formula:

8. The current gain diagnostic method according to claim 6 or 7, used for current loop fault diagnosis of a permanent magnet synchronous motor (PMSM); wherein: If the gain of one phase to be evaluated is abnormal, the corrected current sequence (090) is used to replace the measured current sequence (030) to provide current parameters to the electric drive control system, the preset control system and / or the controller (901).

9. The current gain diagnostic method according to claim 8, wherein: The corrected current sequence (090) is forward-operated and converted into an αβ static current vector (020) to implement the motor vector control; the forward operation includes a Clarke transformation (065) process.

10. A computer storage medium (903), comprising a storage medium body for storing a computer program; when the computer program is executed or called by a microprocessor, the current gain diagnostic method according to any one of claims 1 to 9 is implemented.

11. A current gain diagnosis correction device (600), used to implement the current gain diagnosis method according to any one of claims 1 to 9; comprising a current sensor sequence and a phase current gain observer; wherein: The phase current gain observer comprises a first conversion module (611), a third conversion module (613), a phase current gain calculation module (615), and a phase current gain diagnosis module (617); the first conversion module (611) is used to convert the d-axis and q-axis given currents and the injected d-axis current ic into given currents i*α and i*β in the αβ phase coordinate system; the third conversion module (613) is used to convert the given current i * α and i * β Converted into the given current i of the three phases U, V, and W * u 、i * v 、i * w The phase current gain calculation module (615) is used to calculate the phase current gain correction coefficient, and calculate the corrected phase current i' according to the phase current gain correction coefficient u 、i' v 、i' w The phase current gain diagnosis module (617) is used to determine whether the phase current gain is normal according to the phase current gain correction coefficient, and output a gain status diagnosis indication result.

12. A controller (901), comprising the current gain diagnosis correction device (600) according to claim 11 and / or the computer storage medium (903) according to claim 10.

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