Three-phase permanent magnet synchronous motor fault diagnosis method and diagnosis system

Abstract

The invention discloses a three-phase permanent magnet synchronous motor fault diagnosis method and system, and the three-phase permanent magnet synchronous motor comprises a three-phase winding, a rotor, a rotor position sensor and at least two current sensors which are in star connection, and each current sensor is located on two phases of windings in the three-phase winding. The rotor position sensor is located on a rotor, and the method comprises the following steps: acquiring current values of two phases of windings detected by each current sensor and a rotor position angle detected by the rotor position sensor; by applying a preset voltage to the three-phase windings and according to the current values of the two-phase windings and the rotor position angle, whether each current sensor has a fault or not and whether each-phase winding has a fault or not are determined. By using the method, the current sensor fault and / or the winding fault can be rapidly and accurately determined, and the diagnosis efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motor fault determination, and in particular to a three-phase permanent magnet synchronous motor fault diagnosis method and diagnosis system. Background Art

[0002] In recent years, driven by the development of my country's new energy sector, the installed capacity of electric drive systems has reached record highs. This has intensified competition in this sector while also promoting technological advancement. The reliability and safety of new energy vehicles are key concerns for many automakers and consumers, making early detection of system faults crucial. In automotive electric drive systems, resolvers are typically used to detect motor position angles in real time, while Hall effect current sensors are used to detect two-phase currents. The remaining phase current is calculated based on the sum of the three-phase currents being zero. Therefore, open-circuit faults in the motor windings, resolver faults, and current sensor faults can all directly cause system malfunctions. During operation, resolvers typically provide feedback on their current operating status, and this feedback can be used to directly determine if a resolver fault has occurred. In addition to position and current sensors, electric drive systems are typically equipped with two or more temperature sensors to monitor the temperature of the motor and power components. A temperature sensor failure does not directly cause an electric drive system malfunction.

[0003] Existing methods for diagnosing winding and sensor faults typically utilize algorithmic models to determine whether an open-circuit fault has occurred based on the trajectory of the current along a stationary coordinate system. These methods have limitations in practical application. Algorithms require the proper functioning of the sensors and require the collection of a large number of operating trajectories, which is labor-intensive. Furthermore, the initial data collection consumes a significant amount of memory, leading to insufficient chip storage and trade-offs in system software variables, resulting in inaccurate and rapid fault diagnosis. Summary of the Invention

[0004] The present invention provides a three-phase permanent magnet synchronous motor fault diagnosis method and diagnostic system, which can quickly and accurately determine whether the current sensor and / or rotor position sensor is faulty based on the current value of the winding detected by two current sensors and the rotor position angle detected by the rotor position sensor, thereby achieving rapid positioning and simple logic.

[0005] In a first aspect, the present invention provides a method for diagnosing a fault in a three-phase permanent magnet synchronous motor. The three-phase permanent magnet synchronous motor includes a three-phase winding connected in a star configuration, a rotor, a rotor position sensor, and at least two current sensors. Each current sensor is located on two of the three-phase windings, and the rotor position sensor is located on the rotor. The method includes:

[0006] Obtaining the current values ​​of two phase windings detected by each current sensor and the rotor position angle detected by the rotor position sensor;

[0007] By applying a preset voltage to the three-phase winding and determining whether each current sensor is faulty and whether each phase winding is faulty based on the current value and rotor position angle of two phase windings.

[0008] Optionally, before applying a preset voltage to the three-phase winding and determining whether each current sensor is faulty and whether each phase winding is faulty based on the current values ​​and rotor position angles of two phase windings, the method further includes:

[0009] Make sure that the current sensors are not short-circuited.

[0010] Optionally, determining that each current sensor is not short-circuited includes:

[0011] When it is determined that all current values ​​are 0, it is determined that the current sensor is not short-circuited.

[0012] Optionally, before determining that each current sensor is not short-circuited, the method further includes:

[0013] Verify that the rotor position sensor is not malfunctioning.

[0014] Optionally, by applying a preset voltage to the three-phase winding, determining whether each current sensor is faulty and whether each phase winding is faulty based on the current values ​​and rotor position angles of two phase windings, includes:

[0015] By applying a first preset voltage to the three-phase winding, determining whether each current sensor is faulty and whether each phase winding is faulty according to the current values ​​and rotor position angles of two phase windings;

[0016] When it is not determined whether each current sensor is faulty and whether each phase winding is faulty, a second preset voltage is applied to the three-phase winding to determine whether each current sensor is faulty and whether each phase winding is faulty based on the current values ​​of two phase windings and the rotor position angle; the first preset voltage and the second preset voltage are different.

[0017] Optionally, the three-phase winding includes an A-phase winding, a B-phase winding, and a C-phase winding; the first preset voltage includes U A =U1,U B =-1 / 2U1, U C =1 / 2U1; U1 is the rated voltage of one phase winding;

[0018] The method comprises applying a first preset voltage to the three-phase windings and determining whether each phase winding is faulty according to current values ​​and rotor position angles of two phase windings, including:

[0019] By applying a first preset voltage to the three-phase winding, when the rotor position angle is 0 and at least one current value is 0, it is determined that at least one current sensor is faulty and each phase winding is normal;

[0020] When the rotor position angle is not 0 and all current values ​​are not 0, it is determined that at least one phase winding is faulty and all current sensors are normal;

[0021] When the rotor position angle is not 0 and at least one current value is 0, it is determined that at least one phase winding is faulty and at least one current sensor is faulty;

[0022] When the rotor position angle is not the preset angle and all current values ​​are 0, it is impossible to determine whether each current sensor is faulty or whether each phase winding is faulty.

[0023] Optionally, the current sensor includes a first current sensor and a second current sensor, the first current sensor is located on the A-phase winding, and the second current sensor is located on the B-phase winding;

[0024] When the rotor position angle is 0 and at least one current value is 0, determining that at least one current sensor is faulty includes:

[0025] When the rotor position angle is 0, the first current value detected by the first current sensor is 0, and the second current value detected by the second current sensor is not 0, it is determined that the first current sensor is faulty;

[0026] When the rotor position angle is 0, the first current value detected by the first current sensor is not 0, and the second current value detected by the second current sensor is 0, it is determined that the second current sensor is faulty;

[0027] When the rotor position angle is 0 and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that both the first current sensor and the second current sensor are faulty.

[0028] Optionally, the current sensor includes a first current sensor and a second current sensor, the first current sensor is located on the A-phase winding, and the second current sensor is located on the B-phase winding;

[0029] When the rotor position angle is not 0 and at least one current value is 0, determining that at least one phase winding is faulty and at least one current sensor is faulty includes:

[0030] When the rotor position angle is -30°, the first current value detected by the first current sensor is 0, and the second current value detected by the second current sensor is -I2, it is determined that the C phase winding is faulty and the first current sensor is faulty; I2 is the current in the B phase winding and the C phase winding when one of the phase windings fails;

[0031] When the rotor position angle is -30°, the first current value detected by the first current sensor is I2, and the second current value detected by the second current sensor is 0, it is determined that the C phase winding is faulty and the second current sensor is faulty;

[0032] When the rotor position angle is -30° and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that the C-phase winding is faulty and the first current sensor and the second current sensor are faulty;

[0033] When the rotor position angle is 30°, the first current value detected by the first current sensor is I2, and the second current value detected by the second current sensor is 0, it is determined that the B phase winding is faulty and the second current sensor is normal or faulty;

[0034] When the rotor position angle is 30° and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that the B-phase winding is faulty, the first current sensor is faulty, or both the first current sensor and the second current sensor are faulty.

[0035] Optionally, the three-phase winding includes an A-phase winding, a B-phase winding, and a C-phase winding; the current sensor includes a first current sensor and a second current sensor, the first current sensor is located on the A-phase winding, and the second current sensor is located on the B-phase winding; the second preset voltage includes U A =-1 / 2U1, U B =U1,U C =-1 / 2U1; U1 is the rated voltage of one phase winding;

[0036] By applying a second preset voltage to the three-phase winding, determining whether each current sensor is faulty and whether each phase winding is faulty according to current values ​​and rotor position angles of two phase windings, including:

[0037] By applying a second preset voltage to the three-phase windings, when the rotor position angle is 90°, the first current value detected by the first current sensor is 0, and the second current value detected by the second current sensor is I2, it is determined that the A phase winding is faulty and the first current sensor is normal or faulty; I2 is the current in the B phase winding and the C phase winding when one of the phase windings is faulty;

[0038] When the rotor position angle is 90° and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that the A-phase winding is faulty, the second current sensor is faulty, or both the first current sensor and the second current sensor are faulty;

[0039] When the rotor position angle is the remaining angles, and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that at least two-phase winding faults occur. The remaining angles are degrees excluding 0, ±30° and 90°.

[0040] In a second aspect, the present invention provides a three-phase permanent magnet synchronous motor fault diagnosis system, comprising a star-connected three-phase winding, a rotor, a rotor position sensor, at least two current sensors, and a controller;

[0041] Each current sensor is located on two of the three-phase windings and is used to obtain the current value of the two phase windings;

[0042] The rotor position sensor is located on the rotor and is used to obtain the rotor position angle of the rotor;

[0043] The controller is electrically connected to the rotor position sensor and each current sensor, respectively, for obtaining each current value and rotor position angle; a preset voltage is applied to the three-phase winding, and based on the current value and rotor position angle of two-phase windings, it is determined whether each current sensor and each phase winding is faulty.

[0044] The technical solution of the present invention obtains the current values ​​of two phase windings detected by each current sensor and the rotor position angle detected by the rotor position sensor; applies a preset voltage to the three-phase winding, and determines whether each current sensor and each phase winding are faulty based on the current values ​​of two phase windings and the rotor position angle. This method quickly and accurately determines whether a current sensor and / or rotor position sensor is faulty based on the current values ​​of the windings detected by the two current sensors and the rotor position angle detected by the rotor position sensor, achieving rapid location determination and simple logic.

[0045] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 A flowchart of a three-phase permanent magnet synchronous motor fault diagnosis method provided by an embodiment of the present invention;

[0048] Figure 2 A schematic structural diagram of a three-phase permanent magnet synchronous motor provided by an embodiment of the present invention;

[0049] Figure 3 A schematic diagram of the relationship between the axis of the winding and the rotor position of a three-phase permanent magnet synchronous motor provided by an embodiment of the present invention;

[0050] Figure 4 A flowchart of another three-phase permanent magnet synchronous motor fault diagnosis method provided by an embodiment of the present invention;

[0051] Figure 5 A flowchart of another three-phase permanent magnet synchronous motor fault diagnosis method provided by an embodiment of the present invention;

[0052] Figure 6 An equivalent circuit diagram of a B-phase winding fault provided by an embodiment of the present invention;

[0053] Figure 7 for Figure 6 Schematic diagram of the corresponding synthetic current of the three-phase winding axis. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0055] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0056] In one embodiment, Figure 1 A flowchart of a three-phase permanent magnet synchronous motor fault diagnosis method provided by an embodiment of the present invention is provided. Figure 2 A schematic structural diagram of a three-phase permanent magnet synchronous motor provided by an embodiment of the present invention is shown in FIG. Figure 3A schematic diagram of the relationship between the axis of a three-phase permanent magnet synchronous motor winding and the rotor position is provided in an embodiment of the present invention. This embodiment can be used to quickly and accurately determine whether a winding and a current sensor in a three-phase permanent magnet synchronous motor are faulty. The method can be performed by a three-phase permanent magnet synchronous motor fault diagnosis system. The three-phase permanent magnet synchronous motor includes a star-connected three-phase winding, a rotor (not shown in the figure), a rotor position sensor (not shown in the figure) and at least two current sensors 1. Each current sensor 1 is located on two of the three-phase windings, and the rotor position sensor is located on the rotor. Figures 1 to 3 As shown, the three-phase winding may be an A-phase winding, a B-phase winding, and a C-phase winding, and the method includes:

[0057] S110 , obtaining current values ​​of two phase windings detected by respective current sensors and a rotor position angle detected by a rotor position sensor.

[0058] Among them, the current sensor is set on the winding and is used to detect the current value on the corresponding winding after power is turned on. The rotor position sensor is located on the rotor and is used to detect the rotor position angle corresponding to the rotor after power is turned on. Figure 3 , the three-phase winding is star-connected, that is, the angle between each phase winding is 120°. Under normal circumstances, the initial position of the rotor coincides with the axis of the A-phase winding. Therefore, after power-on, the rotor position angle detected by the rotor position sensor is Figure 3 The angle θ1 in the figure is the angle between the axis of the A-phase winding and the axis of the B-phase winding.

[0059] S120 , applying a preset voltage to the three-phase windings and determining whether each current sensor is faulty and whether each phase winding is faulty based on the current values ​​and rotor position angles of two phase windings.

[0060] The preset voltage is Figure 2 Middle U A , U B and U C , that is, the voltage values ​​applied to the A-phase winding, B-phase winding and C-phase winding respectively. The voltage value can be determined by taking the rated voltage of the A-phase winding as the basis to determine the voltage of the B-phase winding and the C-phase winding, or by taking the rated voltage of the B-phase winding as the basis to determine the voltage of the A-phase winding and the C-phase winding, or by taking the rated voltage of the C-phase winding as the basis to determine the voltage of the A-phase winding and the B-phase winding. The specific determination can be made according to actual conditions and is not limited here.

[0061] It should be noted that the purpose of applying a preset voltage to the three-phase windings in this embodiment is to determine, under the action of the voltage, the current value of the corresponding phase winding detected by the current sensor and the correct current value and rotor position angle that should be output. In other words, a certain preset correspondence exists under the preset voltage: the correspondence between the current value and the preset current value, and the relationship between the rotor position angle and the preset rotor position angle. This allows the actual current values ​​of the two-phase windings to be compared with the preset current values. If they differ, it indicates that the current sensor is faulty. Similarly, the actual rotor position angle can be compared with the preset rotor position angle. If they differ, it indicates that at least one phase winding has a fault. Using this approach, it is possible to quickly and accurately determine whether each current sensor and each winding has a fault, allowing for accurate repair. Furthermore, if the acquired current value and rotor position angle do not fall within the preset relationships, the motor needs to be disassembled and inspected to determine the fault location and cause.

[0062] The technical solution of the embodiments of the present invention obtains the current values ​​of two phase windings detected by each current sensor and the rotor position angle detected by the rotor position sensor; applies a preset voltage to the three-phase winding, and determines whether each current sensor and each phase winding are faulty based on the current values ​​of two phase windings and the rotor position angle. Using this method, based on the current values ​​of the windings detected by the two current sensors and the rotor position angle detected by the rotor position sensor, it is possible to quickly and accurately determine whether the current sensor and / or rotor position sensor are faulty, achieving rapid location determination with simple logic.

[0063] In another specific embodiment, Figure 4 This is a flowchart of another three-phase permanent magnet synchronous motor fault diagnosis method provided by an embodiment of the present invention, referring to Figure 4 As shown, the method includes:

[0064] S210 , obtaining current values ​​of two phase windings detected by respective current sensors and a rotor position angle detected by a rotor position sensor.

[0065] S220: Determine that the rotor position sensor is not faulty.

[0066] Specifically, after obtaining the rotor position angle detected by the rotor position sensor, it is necessary to determine whether the rotor position angle is normal, that is, to determine whether the rotor position sensor is faulty. If no fault occurs, the detected rotor position angle can be used to determine the faults of each phase winding and current sensor. If a fault occurs, the rotor position sensor needs to be repaired, and subsequent steps can be performed after confirming that there is no fault.

[0067] It should be noted that the rotor position sensor is connected to the fault detection structure when it is working. The fault detection structure is used to detect the working state of the rotor position sensor and generate a corresponding fault detection result. Therefore, the fault detection result detected by the fault detection structure and the rotor position angle detected by the rotor position sensor can be obtained at the same time. Among them, the fault detection result detected by the fault detection structure can be realized as a high level or a low level. The high level can indicate that the rotor position sensor is not faulty, and the low level can indicate that the rotor position sensor is faulty; or, the low level can indicate that the rotor position sensor is not faulty, and the high level can indicate that the rotor position sensor is faulty. The specific determination can be made according to the actual situation and is not limited here. In addition, in addition to the above-mentioned level signal output, the output of the fault detection result can also be a direct output of the fault result, or other signal forms that can quickly determine the fault status. This embodiment is not limited here. Therefore, based on the received fault detection result, the fault condition of the rotor position sensor can be quickly determined. When it is determined that the rotor position sensor is faulty, the corresponding fault code can be output, or it can be directly displayed on the display structure to indicate the rotor position sensor fault. Subsequent fault judgment is performed only after it is determined that the rotor position sensor has not failed, thereby avoiding misjudgment and improving accuracy.

[0068] S230: Determine whether each current sensor is short-circuited.

[0069] This step can be refined as follows: when it is determined that all current values ​​are 0, it is determined that the current sensor is not short-circuited.

[0070] Specifically, after determining that the rotor position sensor is not faulty, it is also necessary to determine that the current sensor is not short-circuited to confirm that the current value detected by the current sensor is valid. In this embodiment, based on the current values ​​of two phase windings detected by the two current sensors, if both current values ​​are 0, it can be determined that neither current sensor is short-circuited to ground or the power supply. If it is determined that at least one current value is not 0, it can be determined that the current sensor corresponding to the non-zero current value is short-circuited. The corresponding fault code is then output or directly displayed to indicate that the corresponding current sensor is short-circuited, facilitating maintenance.

[0071] S240 , applying a first preset voltage to the three-phase winding, and determining whether each current sensor is faulty and whether each phase winding is faulty according to current values ​​and rotor position angles of two phase windings.

[0072] Specifically, after determining that each current sensor is not short-circuited, the current sensor and winding fault determination logic is then performed. At this point, applying a first preset voltage to the three-phase winding can be understood as a primary pressure application. Under this first preset voltage, the current values ​​and rotor position angles can be compared with corresponding preset correspondences. If each current value and rotor position angle is determined to fall within a situation described in the preset correspondence, the fault condition of each current sensor and each phase winding can be determined to correspond to the corresponding phenomenon. For example, when the first preset voltage is applied, the preset correspondences can include 11 situations, including the fault causes corresponding to the current values ​​output by the two current sensors and the obtained rotor position angles. Among these 11 situations, one cannot accurately locate the fault cause, requiring a secondary pressure determination. The other 10 situations each correspond to a single fault cause. Therefore, after obtaining the current values ​​and rotor position angles of the two-phase windings, it is determined which of the 10 situations the two current values ​​and rotor position angles fall within, i.e., whether the values ​​are identical. If all three values ​​are identical, the fault diagnosis result corresponds to the fault cause corresponding to that situation, and a secondary pressure determination is not required. When it is determined that the current values ​​and rotor position angles belong to another case, multiple fault causes can be determined under the first preset voltage, but cannot be accurately located. In this case, further judgment is required to locate the fault cause.

[0073] S250. When it is not determined whether each current sensor is faulty and whether each phase winding is faulty, a second preset voltage is applied to the three-phase winding, and based on the current values ​​and rotor position angles of two phase windings, whether each current sensor is faulty and whether each phase winding is faulty is determined.

[0074] The first preset voltage and the second preset voltage are different.

[0075] Specifically, after applying the first preset voltage, if the obtained current values ​​and rotor position angles cannot accurately determine whether each current sensor and each phase winding are faulty within the above-mentioned preset correspondence, a second preset voltage may be applied to the three-phase winding, the second preset voltage being different from the first preset voltage. After applying the second preset voltage, the current values ​​and rotor position angles are again determined to correspond to the fault causes initially determined under the second preset voltage, thereby accurately locating the fault. For example, if it is determined that the current values ​​and rotor position angles correspond to the fault causes that cannot be located under the first preset voltage, a second preset voltage is applied to the three-phase winding. Under the second preset voltage, the current values ​​output by the two current sensors and the obtained rotor position angles are used to determine which fault condition the three-phase winding is faulty. If both the current values ​​and the rotor position angles are determined to correspond to one of the fault conditions, the fault condition of the current sensors and windings can be determined to be a fault within the fault cause corresponding to that condition. In addition, when the current values ​​and rotor position angles do not correspond to the data in all the above cases, the cause of the fault cannot be located and the machine needs to be disassembled for inspection to locate the cause of the fault.

[0076] The technical solution of the embodiment of the present invention determines that the rotor position sensor is not faulty; determines that each current sensor is not short-circuited; applies a first preset voltage to the three-phase winding, and determines whether each current sensor and each phase winding are faulty based on the current values ​​of two phase windings and the rotor position angle; if it is not determined whether each current sensor and each phase winding are faulty, applies a second preset voltage to the three-phase winding, and determines whether each current sensor and each phase winding are faulty based on the current values ​​of two phase windings and the rotor position angle; the first preset voltage and the second preset voltage are different. Using the above method, when it is determined that the rotor position sensor is not faulty and the current sensor is not short-circuited, the fault condition of the current sensor and each phase winding is accurately and quickly located through one or two diagnostics, with simple logic, easy operation, and low cost.

[0077] In another specific embodiment, Figure 5 A flowchart of another three-phase permanent magnet synchronous motor fault diagnosis method provided by an embodiment of the present invention is provided. Figure 6 This is an equivalent circuit diagram of a B-phase winding fault provided by an embodiment of the present invention. Figure 7 for Figure 6 Schematic diagram of the synthetic current of the corresponding three-phase winding axis, wherein the three-phase winding includes an A-phase winding, a B-phase winding, and a C-phase winding, and the current sensor 1 includes a first current sensor 11 and a second current sensor 12, the first current sensor 11 is located on the A-phase winding, and the second current sensor 12 is located on the B-phase winding; Figure 2 、 Figures 5 to 7 As shown, the method includes:

[0078] S310: Acquire current values ​​of two phase windings detected by the current sensors and the rotor position angle detected by the rotor position sensor.

[0079] S320: Determine that the rotor position sensor is not faulty.

[0080] S330: Determine whether each current sensor is short-circuited.

[0081] S340 , by applying a first preset voltage to the three-phase winding, when the rotor position angle is 0 and at least one current value is 0, determine that at least one current sensor is faulty and each phase winding is normal.

[0082] Among them, this step can be refined as follows: when the rotor position angle is 0, the first current value detected by the first current sensor is 0, and the second current value detected by the second current sensor is not 0, it is determined that the first current sensor is faulty; when the rotor position angle is 0, the first current value detected by the first current sensor is not 0, and the second current value detected by the second current sensor is 0, it is determined that the second current sensor is faulty; when the rotor position angle is 0, the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that both the first current sensor and the second current sensor are faulty.

[0083] Specifically, when each current sensor and each phase winding is judged once, a first preset voltage is applied to each phase winding, wherein the first preset voltage includes U A =U1,U B =-1 / 2U1, U C=1 / 2U1; U1 is the rated voltage of one phase winding; for the sake of simplicity, the following explanation will be given using U1 as the rated voltage of the A-phase winding, that is, a voltage equal to the rated voltage U1 is applied to the A-phase winding, a voltage half of the rated voltage U1 and in the opposite direction is applied to the B-phase winding, and a voltage half of the rated voltage U1 and in the same direction is applied to the C-phase winding. At this time, you can refer to Table 1, which is a preset relationship table between the current value detected by a current sensor, the rotor position angle and the corresponding fault cause provided by an embodiment of the present invention, wherein current sensor A is the first current sensor, current sensor B is the second current sensor, the corresponding value of the current sensor A column is the first current value of the A-phase winding detected by the first current sensor, and the corresponding value of the current sensor A column is the second current value of the B-phase winding detected by the second current sensor. It can be seen that when the rotor position angle is 0, corresponding to the preset correspondence table in Table 1, each phase winding is in a normal state. However, the first and second current sensors need to be judged based on the current values. When the rotor position angle is 0, the first current value detected by the first current sensor is I1, and the second current value is -I1 / 2, where I1 is the current generated in the phase A winding after applying the first preset voltage when all three phase windings are normal, this indicates that both the first and second current sensors are normal. When the rotor position angle is 0, the first current value detected by the first current sensor is 0, and the second current value is -I1 / 2, this indicates that the first current sensor is faulty, the second current sensor is normal, and each phase winding is normal. When the rotor position angle is 0, the first current value detected by the first current sensor is I1, and the second current value is 0, this indicates that the second current sensor is faulty, the first current sensor is normal, and each phase winding is normal. When the rotor position angle is 0, the first current value detected by the first current sensor is 0, and the second current value is 0, this indicates that both the first and second current sensors are faulty, and each phase winding is normal. It is understood that, for ease of understanding, when the first current value is I1, the second current value is -I1 / 2, and the rotor position angle is 0, it indicates that the current sensor and each phase winding are normal. Based on the above normal situation, if the obtained first current value is 0 but not I1, it indicates that the first current sensor is faulty. If the second current value is 0 but not -I1 / 2, it indicates that the second current sensor is faulty. If the first current value and the second current value are both 0, it indicates that both the first current sensor and the second current sensor are faulty. When the rotor position angle is not 0, it indicates that at least one phase winding is faulty, but the specific phase winding fault requires specific diagnosis and determination.

[0084] It should be noted that the acquisition method in Table 1 can be achieved by performing simulations or experimental verification based on permutations of single-phase open circuits, multi-phase open circuits, single current sensor faults, and multiple faults. The current values ​​fed back by each current sensor and the rotor position angle values ​​fed back by the rotor position sensor under different fault combinations can be obtained. By analyzing and combining the feedback results, it is found that there are 11 different combinations of values ​​for primary fault judgment as shown in Table 1.

[0085] Table 1: Primary fault judgment table after applying the first preset voltage to each phase winding

[0086]

[0087] S350: When the rotor position angle is not 0 and all current values ​​are not 0, it is determined that at least one phase winding is faulty and all current sensors are normal.

[0088] Continuing with reference to Table 1, when the acquired rotor position angle is not 0, and both the first current value and the second current value are not 0, that is, when the rotor position angle is not 0, the first current value is I2, and the second current value is -I2, where I2 is the current in the B-phase winding and the C-phase winding when one of the phase windings is faulty, corresponding to the preset relationship table in Table 1, it can be determined that at least one phase winding is faulty, but the first current sensor and the second current sensor are normal. In other words, in conjunction with Table 1, when the rotor position angle is -30°, the first current value is I2, and the second current value is -I2, it can be determined that the C-phase winding has an open circuit fault, and the first current sensor and the second current sensor are normal.

[0089] S360: When the rotor position angle is not 0 and at least one current value is 0, determine that at least one phase winding is faulty and at least one current sensor is faulty.

[0090] Among them, this step can be refined as follows: when the rotor position angle is -30°, the first current value detected by the first current sensor is 0, and the second current value detected by the second current sensor is -I2, it is determined that the C phase winding is faulty and the first current sensor is faulty; when the rotor position angle is -30°, the first current value detected by the first current sensor is I2, and the second current value detected by the second current sensor is 0, it is determined that the C phase winding is faulty and the second current sensor is faulty; when the rotor position angle is -30°, the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that the C phase winding is faulty and the first current sensor and the second current sensor are faulty; when the rotor position angle is 30°, the first current value detected by the first current sensor is I2, and the second current value detected by the second current sensor is 0, it is determined that the B phase winding is faulty and the second current sensor is normal or faulty; when the rotor position angle is 30°, the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that the B phase winding is faulty, and the first current sensor is faulty or both the first current sensor and the second current sensor are faulty.

[0091] Specifically, continuing to refer to Table 1, when the acquired rotor position angle is not 0, and at least one current value is 0, that is, the first current value is 0 or the second current value is 0, or the first current value and the second current value are both 0, it can be determined that at least one phase winding is faulty and at least one current sensor is faulty. Specifically, when the rotor position angle is -30°, the first current value is 0, and the second current value is -I2, corresponding to the preset relationship table in Table 1, it can be determined that at this time the C phase winding has an open circuit fault, the first current sensor is faulty, and the second current sensor is normal. When the rotor position angle is -30°, the first current value is I2, and the second current value is 0, corresponding to the preset relationship table in Table 1, it can be determined that at this time the C phase winding has an open circuit fault, the second current sensor is faulty, and the first current sensor is normal. When the rotor position angle is -30°, the first current value and the second current value are both 0, corresponding to the preset relationship table in Table 1, it can be determined that at this time the C phase winding has an open circuit fault, the second current sensor is faulty, and the first current sensor is normal. For simplicity, in the above scenario, when the rotor position angle is -30°, the first current value is I2, and the second current value is -I2, it can be determined that the C-phase winding has an open circuit fault, and the first and second current sensors are normal. Based on this, if the rotor position angles are the same, when the first current value is 0, the first current sensor is determined to be faulty; when the second current value is 0, the second current sensor is determined to be faulty; and when both the first and second current values ​​are 0, both the first and second current sensors are determined to be faulty.

[0092] When the rotor position angle is 30°, the first current value detected by the first current sensor is I2, and the second current value detected by the second current sensor is 0, corresponding to the preset relationship table in Table 1, it can be determined that the B-phase winding has an open circuit fault and the second current sensor is normal or faulty. The reason why the second current sensor is diagnosed as normal or faulty is that when the B-phase winding has a fault, the corresponding first current value is I2 and the second current value is 0. Therefore, when the second current value is 0, it is impossible to determine whether the second current sensor is normal or faulty. It may be 0 when it is normal or it may be 0 when it is faulty.

[0093] When the rotor position angle is 30° and both the first and second current values ​​are 0, the preset relationship table in Table 1 indicates that the B-phase winding is open-circuited, the first current sensor is faulty, or both the first and second current sensors are faulty. Similarly, when the B-phase winding is open-circuited, the rotor position angle is 30°. In this case, the corresponding first current value should be I2 and the second current value should be 0. When the first current value is 0, the first current sensor is faulty. When both the first and second current values ​​are 0, the first current sensor is faulty and the second current sensor is either normal or faulty. The reason is the same as above and will not be explained here.

[0094] In addition, here we take the B-phase winding open circuit fault and the sensor as an example to theoretically explain the 10th case in Table 1 and determine the feedback values ​​of the first current sensor, the second current sensor and the rotor position sensor corresponding to the B-phase winding open circuit fault. Figure 6 and Figure 7 When the B-phase winding is open-circuited, the current value of the B-phase winding is 0, that is, Ib = 0. The A-phase winding and the C-phase winding are connected in series, the current value of the A-phase winding is I2, and the current value of the C-phase winding is -I2, that is, Ia = I2, Ic = -I2. The current of the A-phase winding and the current of the C-phase winding are the same in magnitude and opposite in direction. After vector synthesis, refer to Figure 7 , the resulting composite current vector forms an angle of 30° with the A-axis. This current generates a composite magnetomotive force N and a corresponding magnetic field in the same direction, pulling the rotor permanent magnet to its current position. This results in a rotor position angle of 30°. In summary, when the B-phase winding has an open-circuit fault and all sensors are functioning properly, the first current value, the second current value, and the feedback value of the rotor position angle are (I2, 0, 30°). It is understood that the remaining cases in Table 1 can also be determined using the above analysis method and will not be elaborated on here.

[0095] S370: When the rotor position angle is not the preset angle and all current values ​​are 0, it is impossible to determine whether each current sensor is faulty or whether each phase winding is faulty.

[0096] Specifically, referring to Table 1, when the rotor position angle is not the preset angle and all current values ​​are 0, the preset angle is 0, ±30°, corresponding to the 9th preset relationship in Table 1. The fault may be an open circuit fault of the A-phase winding or multi-phase winding, and the sensor fault is unknown. In other words, at this time, the fault conditions of each phase winding and each current sensor cannot be accurately located, and secondary judgment and positioning are required.

[0097] S380. By applying a second preset voltage to the three-phase winding, when the rotor position angle is 90°, the first current value detected by the first current sensor is 0, and the second current value detected by the second current sensor is I2, it is determined that the A phase winding is faulty and the first current sensor is normal or faulty.

[0098] Specifically, when performing the secondary judgment, it is necessary to apply a second preset voltage to the three-phase winding, wherein the second preset voltage includes U A =-1 / 2U1, U B =U1,U C = -1 / 2U1; U1 is the rated voltage of one phase winding. For ease of understanding, the following explanation uses U1 as the rated voltage of phase A winding as an example. Table 2 shows a preset relationship table between the current values ​​detected by the current sensors, the rotor position angle, and the corresponding fault causes after applying the second preset voltage to the three-phase windings based on the ninth scenario in Table 1. Current sensor A is the first current sensor, current sensor B is the second current sensor, the values ​​corresponding to the column for current sensor A are the first current values ​​of phase A winding detected by the first current sensor, and the values ​​corresponding to the column for current sensor A are the second current values ​​of phase B winding detected by the second current sensor. It can be seen that under this second preset voltage condition, when the acquired first current value is 0, the second current value is I2, and the rotor position angle is 90°, according to the preset relationship table in Table 2, the fault cause can be determined to be a phase A winding fault, and the first current sensor is either normal or faulty. The reasons for the normal and faulty first current sensors are theoretically the same as those described in S360, and reference can be made to S360 for details, which will not be repeated here.

[0099] Table 2 Secondary fault judgment table after applying the second preset voltage to each phase winding

[0100] combination Current sensor A Current sensor B Rotor position angle Cause of failure 9.1 0 <![CDATA[I2]]> 90° A winding is broken, sensor is normal or A is faulty 9.2 0 0 90° A winding is broken, sensor B or AB is faulty 9.3 0 0 <![CDATA[θ1]]> Multi-phase winding open circuit

[0101] It should be noted that the acquisition method in Table 2 can be used based on Table 1 by performing simulations or experimental verification by permuting and combining single-phase open circuit windings, multi-phase open circuits, single current sensor faults, and multiple faults. This allows the current values ​​fed back by each current sensor and the rotor position angle values ​​fed back by the rotor position sensor to be obtained under different fault combinations. By analyzing and combining the feedback results, the three different combinations of secondary fault judgment values ​​shown in Table 2 are obtained.

[0102] S390: When the rotor position angle is 90° and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that the A-phase winding is faulty, the second current sensor is faulty, or both the first current sensor and the second current sensor are faulty.

[0103] Specifically, referring to Table 2, when the rotor position angle is 90° and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, corresponding to the preset correspondence table in Table 2, it can be determined that the fault cause is an open circuit fault of the A-phase winding, a fault of the second current sensor, or a fault of both the first current sensor and the second current sensor. Among them, the reasons why the first current sensor is normal or faulty are the same as the reasons described in S360. Please refer to S360 and will not be repeated here. It can be understood that S380 and S390 can be understood together. When the rotor position angle is 90°, it indicates an open circuit fault of the A-phase winding. On this basis, it can be determined that the first current value is 0 and the second current value is I2. Therefore, when the current value obtained is the same as the above, it can be determined that the first current sensor is normal or faulty, and the second current sensor is normal. When the second current value obtained is also 0, the second current sensor is faulty.

[0104] S400 : When the rotor position angle is any other angle and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that at least two phase windings are faulty.

[0105] The remaining angles are degrees excluding 0, ±30°, and 90°.

[0106] Specifically, referring to Table 2, when the rotor position angle is other angles, the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, where the other angles are degrees excluding 0, ±30° and 90°, corresponding to the preset correspondence table in Table 2, it can only be determined that the cause of the fault is an open circuit fault of multiple sets of windings, but whether it is an open circuit fault of phase A winding and phase B winding, or an open circuit fault of phase A winding and phase C winding, or an open circuit fault of phase B winding and phase C winding cannot be specifically determined, and further diagnostic methods are required.

[0107] The technical solution of the embodiment of the present invention sets a preset relationship table for primary diagnosis and secondary diagnosis, and specifically analyzes the obtained first current value, second current value and rotor position angle. Finally, the corresponding fault cause can be determined, thereby achieving accurate positioning of the fault. The logic is simple and easy to implement.

[0108] Based on the same invention concept, continue to refer to Figure 2 The present invention provides a three-phase permanent magnet synchronous motor fault diagnosis system, which includes a star-connected three-phase winding, a rotor (not shown in the figure), a rotor position sensor (not shown in the figure), at least two current sensors 1 and a controller (not shown in the figure); each current sensor 1 is respectively located on two of the three-phase windings, and is used to obtain the current values ​​of the two phase windings; the rotor position sensor is located on the rotor, and is used to obtain the rotor position angle of the rotor; the controller is electrically connected to the rotor position sensor and each current sensor 1, and is used to obtain each current value and rotor position angle; a preset voltage is applied to the three-phase winding, and whether each current sensor is faulty and whether each phase winding is faulty are determined based on the current values ​​and rotor position angles of two of the phase windings.

[0109] Among them, each current sensor 1 is located on two phase windings in the three-phase winding. Figure 2 The three-phase winding includes an A-phase winding, a B-phase winding, and a C-phase winding. The current sensor 1 includes a first current sensor 11 and a second current sensor 12. The first current sensor 11 is located on the A-phase winding, and the second current sensor 12 is located on the B-phase winding. The first current sensor 11 is used to obtain the first current value of the A-phase winding; the second current sensor 12 is used to obtain the second current value of the B-phase winding. The preset voltage is Figure 2 Middle U A , U B and U C , that is, the voltage values ​​applied to the A-phase winding, B-phase winding and C-phase winding respectively. The voltage value can be determined by taking the rated voltage of the A-phase winding as the standard to determine the voltage of the B-phase winding and the C-phase winding, or by taking the rated voltage of the B-phase winding as the standard to determine the voltage of the A-phase winding and the C-phase winding, or by taking the rated voltage of the C-phase winding as the standard to determine the voltage of the A-phase winding and the B-phase winding. The specific value can be determined according to the actual situation and is not limited here. In addition, refer to Figure 2 The motor also includes an inverter for converting a DC preset voltage applied by the controller into an AC voltage so as to apply pressure to the three-phase winding using the AC voltage.

[0110] It should be noted that the purpose of applying a preset voltage to the three-phase windings by the controller in this embodiment is to determine, under the action of the voltage, the current value of the corresponding phase winding detected by the current sensor and the correct current value and rotor position angle that should be output. In other words, the controller pre-stores a preset correspondence corresponding to the preset voltage, which is the correspondence between current values ​​and preset current values, and between rotor position angles and preset rotor position angles. The controller can then compare the actual current values ​​of the two-phase windings with the preset current values. If they differ, it indicates that the current sensor is faulty. Similarly, the controller can compare the actual rotor position angle with the preset rotor position angle. If they differ, it indicates that at least one phase winding is faulty. Using this approach, it is possible to quickly and accurately determine whether each current sensor and each winding is faulty, allowing for accurate repair. Furthermore, if the controller determines that the acquired current value and rotor position angle do not fall within the preset relationships, the motor needs to be disassembled and inspected to determine the fault location and cause. When the current value is the first current value of the A-phase winding and the second current value of the B-phase winding, the controller determines the cause of the fault based on the current of the A-phase winding and the current of the B-phase winding, as well as the rotor position angle, combined with the preset corresponding relationship to make a comprehensive determination to accurately locate the cause of the fault.

[0111] The three-phase permanent magnet synchronous motor fault diagnosis system provided in the embodiment of the present invention can execute the three-phase permanent magnet synchronous motor fault diagnosis method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0112] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0113] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A three-phase permanent magnet synchronous motor fault diagnosis method, characterized in that: The three-phase permanent magnet synchronous motor includes a star-connected three-phase winding, a rotor, a rotor position sensor, and at least two current sensors, each of the current sensors being located on two of the three-phase windings, and the rotor position sensor being located on the rotor. The method includes: Acquire current values ​​of two phase windings detected by each current sensor and a rotor position angle detected by the rotor position sensor; By applying a preset voltage to the three-phase winding and determining whether each current sensor is faulty and whether each phase of the winding is faulty according to the current values ​​of two of the phase windings and the rotor position angle.

2. The fault diagnosis method according to claim 1, characterized in that: Before applying a preset voltage to the three-phase winding and determining whether each current sensor is faulty and whether each phase winding is faulty based on the current values ​​of two of the phase windings and the rotor position angle, the method further includes: It is determined that each of the current sensors is not short-circuited.

3. The fault diagnosis method according to claim 2, characterized in that: Determining that each of the current sensors is not short-circuited includes: When it is determined that all the current values ​​are 0, it is determined that the current sensor is not short-circuited.

4. The fault diagnosis method according to claim 2, characterized in that: Before determining that each of the current sensors is not short-circuited, the method further includes: Determine that the rotor position sensor is not faulty.

5. The fault diagnosis method according to claim 1, characterized in that: By applying a preset voltage to the three-phase winding, determining whether each current sensor is faulty and whether each phase winding is faulty according to the current values ​​of two phase windings and the rotor position angle, including: By applying a first preset voltage to the three-phase winding, determining whether each current sensor is faulty and whether each phase winding is faulty according to the current values ​​of two phase windings and the rotor position angle; When it is not determined whether each of the current sensors is faulty and whether each of the windings of each phase is faulty, a second preset voltage is applied to the three-phase winding, and based on the current values ​​of two of the phase windings and the rotor position angle, it is determined whether each of the current sensors is faulty and whether each of the windings of each phase is faulty; the first preset voltage and the second preset voltage are different.

6. The fault diagnosis method according to claim 5, characterized in that: The three-phase winding includes an A-phase winding, a B-phase winding and a C-phase winding; the first preset voltage includes U A =U1,U B =-1 / 2U1, U C =1 / 2U1; U1 is the rated voltage of one phase of the winding; The method comprises applying a first preset voltage to the three-phase winding and determining whether the winding of each phase is faulty according to current values ​​of two of the three-phase windings and the rotor position angle, including: By applying a first preset voltage to the three-phase winding, when the rotor position angle is 0 and at least one current value is 0, determining that at least one current sensor is faulty and the windings of each phase are normal; When the rotor position angle is not 0 and the current values ​​are not 0, it is determined that at least one phase of the winding is faulty and the current sensors are normal; When the rotor position angle is not 0 and at least one current value is 0, determining that at least one phase of the winding is faulty and at least one current sensor is faulty; When the rotor position angle is not the preset angle and the current values ​​are all 0, it is impossible to determine whether the current sensors are faulty or whether the windings of each phase are faulty.

7. The fault diagnosis method according to claim 6, characterized in that: The current sensor includes a first current sensor and a second current sensor, the first current sensor is located on the A-phase winding, and the second current sensor is located on the B-phase winding; When the rotor position angle is 0 and at least one current value is 0, determining that at least one current sensor is faulty includes: When the rotor position angle is 0, the first current value detected by the first current sensor is 0, and the second current value detected by the second current sensor is not 0, determining that the first current sensor is faulty; When the rotor position angle is 0, the first current value detected by the first current sensor is not 0, and the second current value detected by the second current sensor is 0, it is determined that the second current sensor is faulty; When the rotor position angle is 0 and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that both the first current sensor and the second current sensor are faulty.

8. The fault diagnosis method according to claim 6, characterized in that: The current sensor includes a first current sensor and a second current sensor, the first current sensor is located on the A-phase winding, and the second current sensor is located on the B-phase winding; When the rotor position angle is not 0 and at least one current value is 0, determining that at least one phase of the winding is faulty and at least one current sensor is faulty includes: When the rotor position angle is -30°, the first current value detected by the first current sensor is 0, and the second current value detected by the second current sensor is -I2, it is determined that the C-phase winding is faulty and the first current sensor is faulty; I2 is the current in the B-phase winding and the C-phase winding when one of the windings is faulty; When the rotor position angle is -30°, the first current value detected by the first current sensor is I2, and the second current value detected by the second current sensor is 0, it is determined that the C-phase winding is faulty and the second current sensor is faulty; When the rotor position angle is -30° and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that the C-phase winding is faulty, and the first current sensor and the second current sensor are faulty; When the rotor position angle is 30°, the first current value detected by the first current sensor is I2, and the second current value detected by the second current sensor is 0, it is determined that the B-phase winding is faulty, and the second current sensor is normal or faulty; When the rotor position angle is 30° and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that the B-phase winding is faulty, the first current sensor is faulty, or both the first current sensor and the second current sensor are faulty.

9. The fault diagnosis method according to claim 5, characterized in that: The three-phase winding includes an A-phase winding, a B-phase winding and a C-phase winding; the current sensor includes a first current sensor and a second current sensor, the first current sensor is located on the A-phase winding, and the second current sensor is located on the B-phase winding; the second preset voltage includes U A =-1 / 2U1, U B =U1,U C =-1 / 2U1; U1 is the rated voltage of one phase of the winding; The method comprises applying a second preset voltage to the three-phase winding and determining whether each current sensor is faulty and whether each phase winding is faulty according to current values ​​of two phase windings and the rotor position angle. By applying the second preset voltage to the three-phase winding, when the rotor position angle is 90°, the first current value detected by the first current sensor is 0, and the second current value detected by the second current sensor is I2, it is determined that the A-phase winding is faulty, and the first current sensor is normal or faulty; I2 is the current in the B-phase winding and the C-phase winding when one of the phase windings is faulty; When the rotor position angle is 90° and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that the A-phase winding is faulty, the second current sensor is faulty, or both the first current sensor and the second current sensor are faulty; When the rotor position angle is the remaining angles, and the first current value detected by the first current sensor and the second current value detected by the second current sensor are both 0, it is determined that at least two phases of the winding are faulty, and the remaining angles are degrees that do not include 0, ±30° and 90°.

10. A three-phase permanent magnet synchronous motor fault diagnosis system, characterized in that: It includes a three-phase winding connected in star configuration, a rotor, a rotor position sensor, at least two current sensors and a controller; Each of the current sensors is located on two of the three-phase windings, and is used to obtain current values ​​of the two phase windings; The rotor position sensor is located on the rotor and is used to obtain the rotor position angle of the rotor; The controller is electrically connected to the rotor position sensor and each current sensor, respectively, and is used to obtain each current value and the rotor position angle; a preset voltage is applied to the three-phase winding, and based on the current values ​​of two of the phase windings and the rotor position angle, it is determined whether each current sensor is faulty and whether each phase winding is faulty.

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