Redundancy control method and system under dual three-phase motor current sensor fault

Abstract

The invention provides a redundancy control method and system under a dual three-phase motor current sensor fault, and belongs to the technical field of three-phase motor control, actual current is estimated based on a current observer, and the current observer obtains an estimated value of phase current through inverse transformation based on a current instruction value of vector control; and comparing the current value estimated by the current observer with an actual sampling value, diagnosing the fault of the current sensor through a set error threshold value, and realizing redundancy control according to a diagnosis result. According to the invention, additional hardware does not need to be added, or the installation position of a conventional current sensor does not need to be changed, for example, the current sensor is additionally arranged on a direct-current bus; the torque output capability can still be realized under the condition that a plurality of current sensors fail at the same time. A basic control scheme does not need to be switched, and control is realized based on vector control under vector space decoupling transformation; when current information is estimated, motor parameters do not need to be used, and the method has high parameter robustness.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-phase motor control, and in particular to a redundant control method and system under fault conditions of dual three-phase motor current sensors. Background Art

[0002] Compared with traditional three-phase motors, dual three-phase permanent magnet synchronous motors (DTP-PMSM) have smoother torque output, higher efficiency and power density, and excellent control performance. In recent years, they have been widely used in aerospace, transportation, and industrial automation. In the traction system of multi-phase permanent magnet synchronous motors, current information is usually collected by current sensors and fed back to the control system to achieve stable control. However, under harsh working conditions, current sensors are prone to failure, resulting in sampling errors, which may cause control system instability. In particular, in DTP-PMSM systems, since the number of current sensors is doubled compared to three-phase systems, the probability of failure increases accordingly.

[0003] Most of the existing research is focused on redundant control under power switch faults in DTP-PMSM stator windings and inverters, but less on redundant control under current sensor faults. Depending on whether an additional current sensor is required, redundant control methods under current sensor faults can be divided into two categories. The first category is a hardware-based method that uses a spare healthy current sensor to replace the faulty current sensor to measure the current. This method is simple and reliable, but it is expensive, increases weight and takes up more space. In addition, there are some methods based on the relationship between the DC bus current and the phase current or the relationship between the branch current and the phase current. During the action time of different space vectors, the currents sampled by the DC bus current sensor and the branch current sensor contain different phase current combinations. Therefore, a single DC bus current or a single branch current can be used to reconstruct the phase current. However, it has problems such as inverter hardware structure compatibility, measurement dead zone, and decreased motor control performance, which makes it difficult to apply. The second category is a software-based method that does not require an additional current sensor. Compared with hardware-based methods, software-based methods are simpler and easier to apply. At present, the redundant control technology under current sensor failure is mainly studied for three-phase motors. The current observer is established through the remaining healthy phase current sensors to obtain the estimated value of the fault phase current. The incorrect current feedback signal is then replaced with the estimated current feedback signal. There are few studies on redundant control of multi-phase motor current sensor failures, and only one-phase current sensor failure is considered. There is no in-depth study on the identification and redundant control of multi-phase current sensor failures.

[0004] In summary, the traction system is based on rotor magnetic field oriented vector control, and provides feedback by measuring physical quantities such as current and speed. As a key component, the current sensor is an indispensable part of the normal operation of the system. If the feedback value is wrong, it will often cause the control system to lose control, resulting in serious consequences. For the traction system with dual three-phase motors as the main body, compared with the commonly used three-phase motor traction system, there are more phase redundancies, which improves the reliability to a certain extent, but the number of current sensors increases exponentially. Under some harsh working conditions, such as long-term vibration, electromagnetic interference, humidity, etc., the probability of sensor failure is higher than that of the switch tube, which reduces the reliability of the system. Summary of the invention

[0005] The object of the present invention is to provide a redundant control method and system under the failure of a dual three-phase motor current sensor, which realizes a certain torque output capacity when at least one current sensor is normal, ensures the safety of the system, maintains the stability of the system, and solves at least one technical problem existing in the above-mentioned background technology.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a redundant control method under a dual three-phase motor current sensor failure, comprising:

[0008] The actual current is estimated based on a current observer, wherein the current observer obtains an estimated value of the phase current based on a current command value of the vector control through an inverse transformation;

[0009] The current value estimated by the current observer is compared with the actual sampled value, and the current sensor fault is diagnosed by setting the error threshold;

[0010] If only one phase current sensor fails, the estimated value of the corresponding phase of the current observer is used instead of the actual sampled current value for redundant control; when two current sensor failures are identified, it is necessary to further determine whether the two normal phase currents are perpendicular to each other. If they are perpendicular, these two phases are brought into the two current sensor vector control; if the normal phase currents are not perpendicular to each other under the failure of two current sensors or three current sensors fail, based on the two current sensor vector control, the current observer is used to estimate the other phase current that is perpendicular to the normal phase current and bring it into the two current sensor vector control for redundant control; if all four current sensors are identified to be faulty, the operation is stopped or switched to open-loop control.

[0011] Furthermore, for a dual three-phase permanent magnet synchronous motor with a 30° difference in neutral point isolation, the six-phase currents are defined as i A 、i B 、i C 、iX 、i Y 、i Z , assuming that the current sensors are arranged in four phases A, B, X, and Y, where are the observed values ​​of the six-phase currents respectively. The fault identification part detects the fault by comparing the observed value with the actual value, and switches different controls for different fault types in the redundant control part. D 、i Q 、i D0 、i Q0 They are the actual values ​​of the direct and quadrature axis currents of the fundamental sub-plane and the currents of the harmonic sub-plane after vector space decoupling transformation, are the direct-axis currents of the fundamental sub-plane and the current command values ​​of the harmonic sub-plane after vector space decoupling transformation, S is the switching flag of redundant control under the failure of two current sensors, when S=0, the harmonic plane is closed-loop control, when S=1, the harmonic plane switches to open-loop control.

[0012] Furthermore, the current observer used is based on the current loop command value to inversely calculate the estimated value of each phase current. Assuming that the command value is equal to the actual value, the estimated value of the six-phase current can be calculated from the current loop command value according to the vector space coordinate inverse transformation matrix:

[0013]

[0014] Furthermore, the current value estimated by the current observer is compared with the actual sampling value, and the current sensor fault is diagnosed by setting the error threshold, including: firstly, calculating the error between the observed current value and the actual value, and sending the value of each phase error to the hysteresis comparator respectively, the lower limit of the hysteresis threshold is set to 0, and the upper limit is set according to the actual operating conditions. When the error exceeds the threshold, the current sensor of the corresponding phase is faulty. When the four-phase current sampling error is within the normal range, the hysteresis comparator outputs 0, when the A phase fails, it outputs 1, when the B phase fails, it outputs 2, when the X phase fails, it outputs 4, and when the Y phase fails, it outputs 8. The output results of the four-phase hysteresis comparators are added as the fault word E, and different controls are switched by identifying the fault word. When E=0, there is no current sensor fault at this time, and the original state is maintained. Normal control comes from, and S=0; when E=1 / 2 / 4 / 8, a single current sensor fault occurs at this time, and it is switched to redundant control under single current sensor fault, and S=0; when E=3 / 4 / 9 / 6 / 10 / 12, a two-phase current sensor fault occurs, and it is necessary to further determine whether the normal phase current sensors are two phases perpendicular to each other, that is, whether E=9 is established. If E=9 is satisfied, it is switched to two current sensor redundant control, and S=1. If E is not 9, it is switched to redundant control under single current sensor, and S=1; when E=7 / 11 / 13 / 14, a three-phase current sensor fault occurs, and it is switched to redundant control under single current sensor, and S=1; if E=15, all four-phase current sensors fail, and a fault shutdown is required.

[0015] Further, redundant control under single current sensor fault: when a single current sensor fault is identified, that is, when the fault word E = 1 / 2 / 4 / 8, switch to redundant control under single current sensor fault; based on the current observer, the observed fault phase current is brought into the control; assuming that the B phase current sensor fails, the fault word E = 2, the estimated value of the B phase current The vector space decoupling transformation fundamental sub-plane AC and DC axis current and harmonic sub-plane current estimation values ​​are obtained

[0016]

[0017] Further, redundant control under two current sensors: When two current sensors fail and the normal phase currents are perpendicular to each other, that is, the fault word E=9, due to the particularity of the dual three-phase motor structure studied, when the two sets of windings are 30° apart, there are always two mutually orthogonal vectors. Therefore, when the direction of the A vector is the positive direction of the α axis and the negative direction of the Z vector is the positive direction of the β axis, based on the equal-amplitude Clark transformation matrix; for the vector control under the vector space decoupling transformation, it includes a speed outer loop and four current loops, and the two current loops (i D 、i Q) Its current control is equivalent to the three-phase motor control system, realizing the electromechanical energy conversion of the motor, where the reference value of the d-axis current is 0, corresponding to the i of the three-phase motor d = 0, the two current loops in the z1-z2 subspace (i zl 、i z2 ) to control harmonics.

[0018] In a second aspect, the present invention provides a redundant control system under a dual three-phase motor current sensor failure, comprising:

[0019] An estimation module, used for estimating the actual current based on a current observer, wherein the current observer obtains an estimated value of the phase current by inverse transformation based on the current command value of the vector control;

[0020] A diagnostic module is used to compare the current value estimated by the current observer with the actual sampled value, and diagnose the current sensor fault through the set error threshold;

[0021] The control module is used for performing redundant control by using the estimated value of the corresponding phase of the current observer instead of the actual sampled current value if only one phase current sensor fails; when two current sensors are identified to be faulty, it is necessary to further determine whether the two normal phase currents are perpendicular to each other. If they are perpendicular, the two phases are brought into the two current sensor vector control; if the normal phase currents are not perpendicular to each other under the fault of two current sensors or when three current sensors fail, based on the two current sensor vector control, the current observer is used to estimate the other phase current that is perpendicular to the normal phase current and bring it into the two current sensor vector control for redundant control; if all four current sensors are identified to be faulty, the operation is stopped or switched to open-loop control.

[0022] In a third aspect, the present invention provides a non-transitory computer-readable storage medium, which is used to store computer instructions. When the computer instructions are executed by a processor, the redundant control method under the fault of the dual three-phase motor current sensor as described in the first aspect is implemented.

[0023] In a fourth aspect, the present invention provides a computer device comprising a memory and a processor, wherein the processor and the memory communicate with each other, the memory stores program instructions executable by the processor, and the processor calls the program instructions to execute the redundant control method under the fault of the dual three-phase motor current sensor as described in the first aspect.

[0024] In a fifth aspect, the present invention provides an electronic device, comprising: a processor, a memory and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory so that the electronic device executes instructions for implementing the redundant control method under the fault of the dual three-phase motor current sensor as described in the first aspect.

[0025] The beneficial effects of the present invention are as follows: there is no need to add additional hardware or change the installation position of conventional current sensors, such as installing current sensors on the DC bus. It can achieve torque output capability even when multiple current sensors fail at the same time. There is no need to switch the basic control scheme, and control is achieved based on vector control under vector space decoupling transformation. When estimating current information, there is no need to use motor parameters, and the system has strong parameter robustness.

[0026] Additional advantages of the present invention will be more clearly given in the following description or learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0028] Figure 1 The present invention provides an overall block diagram of a redundant control method for a dual three-phase permanent magnet synchronous motor under current sensor failure.

[0029] Figure 2 A schematic diagram of a fault classification method in a fault identification module according to an embodiment of the present invention.

[0030] Figure 3 The figure is an overall block diagram of the redundant control method under a single-phase current sensor failure (phase B) according to an embodiment of the present invention.

[0031] Figure 4 Schematic diagram of the relationship between the current vectors of each phase of a double-Y DTP-PMSM with a 30° difference in neutral point isolation according to an embodiment of the present invention.

[0032] Figure 5 The figure is an overall block diagram of a redundant control method under fault conditions of one or two current sensors according to an embodiment of the present invention.

[0033] Figure 6 The figure is an overall block diagram of a redundant control method under three current sensor failures according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below by the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0035] It should be understood by those skilled in the art that unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs.

[0036] It should also be understood that terms, such as those defined in commonly used dictionaries, should be understood to have a meaning consistent with that in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless as defined herein.

[0037] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements and / or groups thereof.

[0038] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. Different embodiments or examples described in this specification and features of different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

[0039] To facilitate understanding of the present invention, the present invention is further explained below with reference to specific embodiments in conjunction with the accompanying drawings, and the specific embodiments do not constitute a limitation on the embodiments of the present invention.

[0040] Those skilled in the art should understand that the drawings are merely schematic diagrams of embodiments, and the components in the drawings are not necessarily necessary for implementing the present invention.

[0041] Example 1

[0042] In this embodiment 1, a redundant control system under the fault of a dual three-phase motor current sensor is first provided, comprising: an estimation module, used to estimate the actual current based on a current observer, wherein the current observer obtains an estimated value of the phase current by inverse transformation based on the current command value of the vector control; a diagnosis module, used to compare the current value estimated by the current observer with the actual sampled value, and diagnose the current sensor fault through a set error threshold; a control module, used to use the estimated value of the corresponding phase of the current observer to replace the actual sampled current value for redundant control if only one phase current sensor fails; when two current sensor failures are identified, it is necessary to further determine whether the two normal phase currents are perpendicular to each other, and if they are two perpendicular phases, the two phases are brought into the two current sensor vector control; if the normal phase currents are not perpendicular to each other under the fault of two current sensors or when three current sensors fail, based on the two current sensor vector control, the current observer is used to estimate the other phase current that is perpendicular to the normal phase current, and bring it into the two current sensor vector control for redundant control; if all four current sensors are identified to be faulty, the operation is stopped or switched to open-loop control.

[0043] like Figures 1 to 6 As shown, in this embodiment, the above system is used to implement a redundant control method under a dual three-phase motor current sensor failure, so that when a current sensor of the DTP-PMSM fails, at least one current sensor can work normally, and still maintain a high current loop control accuracy.

[0044] The DTP-PMSM current sensor fault redundant control method comprises the following steps: first, estimating the actual current based on the current observer, the current observer used in this embodiment obtains the estimated value of the phase current by inverse transformation based on the current command value of the vector control; second, comparing the current value estimated by the current observer with the actual sampled value, and realizing the diagnosis of the current sensor fault by setting a suitable error threshold; third, if only one phase current sensor fails, the estimated value of the corresponding phase of the current observer is used to replace the actual sampled current value for redundant control; third, when two current sensor failures are identified, it is necessary to further determine whether the two normal phase currents are perpendicular to each other. If they are two vertical phases, the two phases are brought into the two current sensor vector control proposed by the present invention; fourth, if the normal phase currents are not perpendicular to each other under the failure of two current sensors or three current sensors fail, based on the two current sensor vector control, the current observer is used to estimate the other phase current that is perpendicular to the normal phase current, and it is brought into the two current sensor vector control for redundant control; fifth, if all four current sensors are identified to be faulty, the operation is stopped or switched to open-loop control.

[0045] Step 1: Current estimation of dual three-phase permanent magnet synchronous motor based on current observer

[0046] like Figure 1 The figure shows the overall block diagram of redundant control under the current sensor failure of a dual three-phase permanent magnet synchronous motor. The object of study in this embodiment is a dual Y-phase permanent magnet synchronous motor with a 30° difference in neutral point isolation. The six-phase currents are defined as i A 、i B 、i C 、i X 、i Y 、i Z , assuming that the current sensors are arranged in the four phases A, B, X, and Y. In this embodiment, the redundant control is implemented based on the vector control under the vector space decoupling transformation, and three parts, namely, the current observer, the fault identification, and the redundant control, are added. are the observed values ​​of the six-phase currents respectively. The fault identification part detects the fault by comparing the observed value with the actual value, and switches different controls for different fault types in the redundant control part. D 、i Q 、i D0 、i Q0 They are the actual values ​​of the direct and quadrature axis currents of the fundamental sub-plane and the currents of the harmonic sub-plane after vector space decoupling transformation, They are respectively the AC and DC axis currents of the fundamental sub-plane and the current command values ​​of the harmonic sub-plane after vector space decoupling transformation. S is the switching flag of the redundant control under the failure of the two current sensors proposed in this patent. When S=0, the harmonic plane is closed-loop control, and when S=1, the harmonic plane switches to open-loop control.

[0047] In this embodiment, the current observer used obtains the estimated value of each phase current based on the current loop command value by reverse calculation. Assuming that the command value is equal to the actual value, the estimated value of the six-phase current can be calculated from the current loop command value according to the vector space coordinate inverse transformation matrix of formula (1).

[0048]

[0049] Step 2: Dual three-phase permanent magnet synchronous motor current sensor fault identification

[0050] like Figure 2The figure shows the current sensor fault identification process. First, the error between the observed current value and the actual value is calculated, and the error value of each phase is sent to the hysteresis comparator. The lower limit of the hysteresis threshold is set to 0, and the upper limit is set according to the actual operating conditions. When the error exceeds the threshold, the current sensor of the corresponding phase is faulty. When the four-phase current sampling error is within the normal range, the hysteresis comparator outputs 0, when the A phase fails, it outputs 1, when the B phase fails, it outputs 2, when the X phase fails, it outputs 4, and when the Y phase fails, it outputs 8. The output results of the four-phase hysteresis comparators are added as the fault word E. By identifying the fault word, different controls are switched. When E = 0, there is no current sensor fault at this time, and the original normal control is maintained. At the same time, S = 0; when E = 1 / 2 / At 4 / 8, a single current sensor failure occurs, and the control mode is switched to redundant control under a single current sensor failure, and S=0; when E=3 / 4 / 9 / 6 / 10 / 12, a two-phase current sensor failure occurs, and it is necessary to further determine whether the normal phase current sensors are two phases perpendicular to each other, that is, whether E=9 is established. If E=9 is satisfied, it is switched to two-current sensor redundant control, and S=1. If E is not 9, it is switched to redundant control under a single current sensor, and S=1; when E=7 / 11 / 13 / 14, a three-phase current sensor failure occurs, and it is switched to redundant control under a single current sensor, and S=1; if E=15, all four-phase current sensors fail, and a failure shutdown is required.

[0051] Step 3: Redundant control under single current sensor failure:

[0052] When a single current sensor fault is identified, that is, when the fault word E=1 / 2 / 4 / 8, the control switches to redundant control under the single current sensor fault.

[0053] like Figure 3 The figure shows the overall block diagram of a redundant control method under a single-phase current sensor fault (phase B) according to an embodiment of the present invention. Based on the current observer, the observed fault phase current is brought into the control. Assuming that the phase B current sensor fails, the fault word E = 2, and the estimated value of the phase B current is obtained by formula (1): And the estimated values ​​of the direct and quadrature axis currents of the fundamental sub-plane and the currents of the harmonic sub-plane of the vector space decoupling transformation are obtained by equation (2):

[0054]

[0055] Step 3: Redundant control with two current sensors

[0056] When two current sensors fail and the normal phase currents are perpendicular to each other, that is, the fault word E = 9, Figure 4As shown, due to the particularity of the dual three-phase motor structure studied, when the two sets of windings are 30° apart, there are always two mutually orthogonal vectors. Therefore, when the direction of the A vector is the positive direction of the α axis and the negative direction of the Z vector is the positive direction of the β axis, the equal-amplitude Clark transformation matrix is ​​as shown in formula (3):

[0057]

[0058] Assume that the six-phase currents are:

[0059]

[0060] The six-phase current of the motor is transformed into space vector coordinates and transformed using the product-to-difference formula to obtain:

[0061]

[0062] Similarly, when the direction of the X vector is the positive direction of the α axis and the positive direction of the B vector is the positive direction of the β axis, based on the equal-amplitude Clark transform, we can get:

[0063]

[0064] When the direction of the Y vector is the positive direction of the α axis and the negative direction of the C vector is the positive direction of the β axis, based on the equal-amplitude Clark transformation, we can obtain:

[0065]

[0066] The vector control under the vector space decoupling transformation includes a speed outer loop and four current loops. The two current loops (i D 、i Q ) Its current control is equivalent to the three-phase motor control system, realizing the electromechanical energy conversion of the motor, where the reference value of the d-axis current is 0, corresponding to the i of the three-phase motor d = 0, you can also refer to the MTPA control of three-phase motors. The two current loops (i zl 、i z2 ) is mainly used to control harmonics. In the absence of current sampling information, in order to ensure the output capacity of the motor torque under certain special circumstances, it is possible to consider sacrificing the motor control performance and open-loop control the harmonic z1-z2 plane. In this embodiment, the two current sensors are based on the harmonic plane open-loop control.

[0067] Substituting equation (6) into equation (8), we can get D with i Q Closed-loop control:

[0068]

[0069] Under normal circumstances, the sensor will only collect the four-phase current of A, B, X, and Y. Therefore, two current sensors can be used for control only when the B and X phase current sensors are normal.

[0070] Step 4: Redundant control under single current sensor

[0071] When two current sensors fail and the healthy phases are not perpendicular to each other or three current sensors fail, that is, the fault word E = 3 / 5 / 6 / 10 / 12 / 7 / 11 / 13 / 14, based on the two current sensor control, if the remaining healthy phase is phase A, the fault word E = 14, based on formula (1), we can get i z The estimated value of is the actual instruction value, The value of is 0. Based on equation (5) and equation (8), we can get i D 、i Q The estimated value of is substituted into the control. The overall control block diagram is as follows Figure 6 shown.

[0072] Step 5: Four-phase current sensor failure

[0073] When all current sensors fail, that is, fault word E=15, the necessary parameters required for control are missing and control cannot be completed. The motor needs to be forced to stop or switch to open-loop control that does not require current sensors.

[0074] Example 2

[0075] This embodiment 2 provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by a processor, the redundant control method under the condition of a dual three-phase motor current sensor failure as described above is implemented. The method includes:

[0076] The actual current is estimated based on a current observer, wherein the current observer obtains an estimated value of the phase current based on a current command value of the vector control through an inverse transformation;

[0077] The current value estimated by the current observer is compared with the actual sampled value, and the current sensor fault is diagnosed by setting the error threshold;

[0078] If only one phase current sensor fails, the estimated value of the corresponding phase of the current observer is used instead of the actual sampled current value for redundant control; when two current sensor failures are identified, it is necessary to further determine whether the two normal phase currents are perpendicular to each other. If they are perpendicular, these two phases are brought into the two current sensor vector control; if the normal phase currents are not perpendicular to each other under the failure of two current sensors or three current sensors fail, based on the two current sensor vector control, the current observer is used to estimate the other phase current that is perpendicular to the normal phase current and bring it into the two current sensor vector control for redundant control; if all four current sensors are identified to be faulty, the operation is stopped or switched to open-loop control.

[0079] Example 3

[0080] This embodiment 3 provides a computer device, including a memory and a processor, the processor and the memory communicate with each other, the memory stores program instructions that can be executed by the processor, the processor calls the program instructions to execute the redundant control method under the fault of the dual three-phase motor current sensor as described above, the method comprising:

[0081] The actual current is estimated based on a current observer, wherein the current observer obtains an estimated value of the phase current based on a current command value of the vector control through an inverse transformation;

[0082] The current value estimated by the current observer is compared with the actual sampled value, and the current sensor fault is diagnosed by setting the error threshold;

[0083] If only one phase current sensor fails, the estimated value of the corresponding phase of the current observer is used instead of the actual sampled current value for redundant control; when two current sensor failures are identified, it is necessary to further determine whether the two normal phase currents are perpendicular to each other. If they are perpendicular, these two phases are brought into the two current sensor vector control; if the normal phase currents are not perpendicular to each other under the failure of two current sensors or three current sensors fail, based on the two current sensor vector control, the current observer is used to estimate the other phase current that is perpendicular to the normal phase current and bring it into the two current sensor vector control for redundant control; if all four current sensors are identified to be faulty, the operation is stopped or switched to open-loop control.

[0084] Example 4

[0085] This embodiment 4 provides an electronic device, including: a processor, a memory, and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory to enable the electronic device to execute instructions for implementing the redundant control method under the fault of the dual three-phase motor current sensor as described above, the method comprising:

[0086] The actual current is estimated based on a current observer, wherein the current observer obtains an estimated value of the phase current based on a current command value of the vector control through an inverse transformation;

[0087] The current value estimated by the current observer is compared with the actual sampled value, and the current sensor fault is diagnosed by setting the error threshold;

[0088] If only one phase current sensor fails, the estimated value of the corresponding phase of the current observer is used instead of the actual sampled current value for redundant control; when two current sensor failures are identified, it is necessary to further determine whether the two normal phase currents are perpendicular to each other. If they are perpendicular, these two phases are brought into the two current sensor vector control; if the normal phase currents are not perpendicular to each other under the failure of two current sensors or three current sensors fail, based on the two current sensor vector control, the current observer is used to estimate the other phase current that is perpendicular to the normal phase current and bring it into the two current sensor vector control for redundant control; if all four current sensors are identified to be faulty, the operation is stopped or switched to open-loop control.

[0089] In summary, the redundant control method for the dual three-phase motor current sensor failure described in the embodiment of the present invention does not require the installation of additional current sensors, and only uses the existing current sensors and position sensors in the system to perform fault identification and redundant control, saving space and cost, and improving the stability of the system. A corresponding redundant control scheme is proposed for the situation where multiple current sensors of the dual three-phase motor fail, so that a certain torque output capacity is still achieved when at least one current sensor is normal.

[0090] The present invention uses a current observer to estimate the current of each phase and perform current sensor fault diagnosis. Compared with the method of installing multiple current sensors for hardware redundancy, the redundant control method provided by the present invention does not require the additional installation of current sensors and voltage sensors, and has the advantages of small size, light weight, low consumption cost, easy implementation, wide application range, space saving, and easy maintenance. The dual three-phase permanent magnet synchronous motor redundant control proposed by the present invention also achieves a high current loop control accuracy under multiple current sensor failures, reduces the impact of sensor failures, and maintains the stability of the system.

[0091] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0092] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0093] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0094] These computer program instructions can also be loaded onto a computer or other programmable data processing device, and a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0095] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative work on the basis of the technical solution disclosed in the present invention should be included in the scope of protection of the present invention.

Claims

1. A redundant control method for a dual three-phase motor current sensor failure, characterized in that: include: The actual current is estimated based on a current observer, wherein the current observer obtains an estimated value of the phase current based on a current command value of the vector control through an inverse transformation; The current value estimated by the current observer is compared with the actual sampled value, and the current sensor fault is diagnosed by setting the error threshold; If only one phase current sensor fails, the estimated value of the corresponding phase of the current observer is used instead of the actual sampled current value for redundant control; when two current sensor failures are identified, it is necessary to further determine whether the two normal phase currents are perpendicular to each other. If they are perpendicular, these two phases are brought into the two current sensor vector control; if the normal phase currents are not perpendicular to each other under the failure of two current sensors or three current sensors fail, based on the two current sensor vector control, the current observer is used to estimate the other phase current that is perpendicular to the normal phase current and bring it into the two current sensor vector control for redundant control; if all four current sensors are identified to be faulty, the operation is stopped or switched to open-loop control.

2. The redundant control method under dual three-phase motor current sensor failure according to claim 1 is characterized in that: The six-phase currents of the permanent magnet synchronous motor with double Y phases separated by 30° and isolated neutral points are defined as i A 、i B 、i C 、i X 、i Y 、i Z , assuming that the current sensors are arranged in four phases A, B, X, and Y, where are the observed values ​​of the six-phase currents respectively. The fault identification part detects the fault by comparing the observed value with the actual value, and switches different controls for different fault types in the redundant control part. D 、i Q 、i D0 、i Q0 They are the actual values ​​of the direct and quadrature axis currents of the fundamental sub-plane and the currents of the harmonic sub-plane after vector space decoupling transformation, are the direct-axis currents of the fundamental sub-plane and the current command values ​​of the harmonic sub-plane after vector space decoupling transformation, S is the switching flag of redundant control under the failure of two current sensors, when S=0, the harmonic plane is closed-loop control, when S=1, the harmonic plane switches to open-loop control.

3. The redundant control method under the condition of dual three-phase motor current sensor failure according to claim 2 is characterized in that: The current observer used is based on the current loop command value to inversely calculate the estimated value of each phase current. Assuming that the command value is equal to the actual value, the estimated value of the six-phase current can be calculated from the current loop command value according to the vector space coordinate inverse transformation matrix:

4. The redundant control method under dual three-phase motor current sensor failure according to claim 2, characterized in that: The current value estimated by the current observer is compared with the actual sampling value, and the current sensor fault is diagnosed by setting the error threshold, including: first calculating the error between the observed current value and the actual value, and sending the value of each phase error to the hysteresis comparator respectively, the lower limit of the hysteresis threshold is set to 0, and the upper limit is set according to the actual operating conditions. When the error exceeds the threshold, the current sensor of the corresponding phase is faulty. When the four-phase current sampling error is within the normal range, the hysteresis comparator outputs 0, when the A phase fails, it outputs 1, when the B phase fails, it outputs 2, when the X phase fails, it outputs 4, and when the Y phase fails, it outputs 8. The output results of the four-phase hysteresis comparators are added as the fault word E, and different controls are switched by identifying the fault word. When E=0, there is no current sensor fault at this time, and the original positive Normal control, and S=0; when E=1 / 2 / 4 / 8, a single current sensor fault occurs, and it is switched to redundant control under a single current sensor fault, and S=0; when E=3 / 4 / 9 / 6 / 10 / 12, a two-phase current sensor fault occurs, and it is necessary to further determine whether the normal phase current sensors are two phases perpendicular to each other, that is, whether E=9 is established. If E=9 is satisfied, it is switched to two-current sensor redundant control, and S=1. If E is not 9, it is switched to redundant control under a single current sensor, and S=1; when E=7 / 11 / 13 / 14, a three-phase current sensor fault occurs, and it is switched to redundant control under a single current sensor, and S=1; if E=15, all four-phase current sensors fail, and a fault shutdown is required.

5. The redundant control method under dual three-phase motor current sensor failure according to claim 2, characterized in that: Redundant control under single current sensor fault: When a single current sensor fault is identified, that is, when the fault word E=1 / 2 / 4 / 8, switch to redundant control under single current sensor fault; Based on the current observer, the observed fault phase current is brought into the control; Assume that the B-phase current sensor fails, the fault word E = 2, and the estimated value of the B-phase current is The vector space decoupling transformation fundamental sub-plane AC and DC axis current and harmonic sub-plane current estimation values ​​are obtained 6. The redundant control method under dual three-phase motor current sensor failure according to claim 5, characterized in that: Redundant control under two current sensors: When two current sensors fail and the normal phase currents are perpendicular to each other, that is, the fault word E=9, due to the particularity of the dual three-phase motor structure studied, when the two sets of windings are 30° apart, there are always two mutually orthogonal vectors. Therefore, when the direction of the A vector is the positive direction of the α axis and the negative direction of the Z vector is the positive direction of the β axis, based on the equal-amplitude Clark transformation matrix; for the vector control under the vector space decoupling transformation, it includes a speed outer loop and four current loops, and the two current loops (i D 、i Q ) Its current control is equivalent to the three-phase motor control system, realizing the electromechanical energy conversion of the motor, where the reference value of the d-axis current is 0, corresponding to the i of the three-phase motor d = 0, the two current loops in the z1-z2 subspace (i zl 、i z2 ) to control harmonics.

7. A redundant control system under dual three-phase motor current sensor failure, characterized in that: include: An estimation module, used for estimating the actual current based on a current observer, wherein the current observer obtains an estimated value of the phase current by inverse transformation based on the current command value of the vector control; A diagnostic module is used to compare the current value estimated by the current observer with the actual sampled value, and diagnose the current sensor fault through the set error threshold; The control module is used for performing redundant control by using the estimated value of the corresponding phase of the current observer instead of the actual sampled current value if only one phase current sensor fails; when two current sensors are identified to be faulty, it is necessary to further determine whether the two normal phase currents are perpendicular to each other. If they are perpendicular, the two phases are brought into the two current sensor vector control; if the normal phase currents are not perpendicular to each other under the fault of two current sensors or when three current sensors fail, based on the two current sensor vector control, the current observer is used to estimate the other phase current that is perpendicular to the normal phase current and bring it into the two current sensor vector control for redundant control; if all four current sensors are identified to be faulty, the operation is stopped or switched to open-loop control.

8. A non-transitory computer-readable storage medium, characterized in that: The non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by the processor, the redundant control method under the failure of the dual three-phase motor current sensor as described in any one of claims 1-6 is implemented.

9. A computer device, characterized in that: It includes a memory and a processor, the processor and the memory communicate with each other, the memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the redundant control method under the fault of the dual three-phase motor current sensor as described in any one of claims 1-6.

10. An electronic device, characterized in that: include: A processor, a memory and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory so that the electronic device executes instructions for implementing the redundant control method under the fault of the dual three-phase motor current sensor as described in any one of claims 1-6.

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