Anomaly diagnostic device and anomaly diagnostic procedure

Abstract

Anomaly diagnostic device (22) designed to detect a drive anomaly of a single motor (16) driven by a plurality of motor drive devices (14); wherein the majority of motor drive devices (14) drive the motor (16) by supplying a majority of three-phase windings (17) which the motor (16) has with a three-phase alternating current; the anomaly detection device (22) comprises: a speed acquisition unit (42) designed to acquire a speed value (Ved) of the motor (16); a power generation unit (40) configured to obtain values ​​of phase currents from the respective phases flowing through the three-phase windings (17); and a detection unit (44) which is designed to determine whether an absolute value of the rotational speed (Ved) exceeds a predetermined value (SV) and to determine, if an absolute value of the rotational speed (Ved) exceeds the predetermined value (SV) and if an absolute value of the phase current of any phase of the three-phase windings (17) is less than a threshold value (TH) over a predetermined period, that an anomaly exists in which the phase of the three-phase windings (17) is interrupted, and wherein the determination unit (44) changes the threshold value (TH) depending on a size of the absolute value of the rotational speed value (Ved).

Description

Background of the invention: Area of ​​the invention:

[0001] The present invention relates to an anomaly diagnostic device and an anomaly diagnostic method for detecting a drive anomaly of a single motor driven by a plurality of motor drive devices. Description of the related technique:

[0002] Document JP 2005-102409A discloses a printing device that detects an anomaly in relation to a motor drive device controlling a motor. In brief, the printing device comprises a plurality of phase detection circuits connected to each of a plurality of motor phases (Phase A, Phase *A, Phase B, Phase *B), and includes a first detection circuit configured to detect the occurrence of an anomaly in relation to pulses output to the motor phases, a second detection circuit configured to detect the occurrence of an overcurrent in the motor phases, and logic output devices that perform logic outputs indicating anomalies in relation to the motor drive device based on the detection results from the plurality of phase detection circuits.

[0003] A reduced-voltage motor starter is known from US patent 4,724,503 A. The starter includes a semiconductor switch for controlling the application of power to a motor, with a current ramp acceleration control circuit for gradually starting the motor. The acceleration control circuit includes means for providing a reference for a relatively low current and means for preselecting a starting time period. Additionally, means are provided for controlling the semiconductor switch to cause the motor current to gradually increase from the low-current reference to the high-current reference during the preselected period. Furthermore, the starter includes an underload detection circuit with means for detecting when the motor current falls below a preselected reference level after the motor has reached operating speed. Upon detection of such a condition, the power supply to the motor is interrupted.

[0004] From US Patent 2013 / 0179040A1, an electric power steering system with a steering wheel and a steering shaft is known. The steering shaft includes a column shaft, with a motor connected to the column shaft as a drive source and driving it via a gearbox. The motor is designed such that independent motor coils with two systems are wound around a stator. A first system motor coil and a second system motor coil are each wound around teeth of the stator. A detection unit designed to determine whether at least one phase of at least one phase winding is interrupted is not provided.

[0005] From DE 10 2010 005 008 A1, an electric tool is known that comprises an AC motor, a switching device that switches the AC voltage applied to the motor according to a line angle, a speed control unit for setting a target speed of the motor, a speed detection unit for detecting the actual speed of the motor, and a control unit that determines the line angle based on a comparison of the actual and target speeds and controls the switching device using the line angle based on a maximum line angle defined according to the target speed. It is known from DE 3 that a fundamental problem is that the speed is subject to transient processes when the motor is started.

[0006] US Patent 5,703,459 A discloses a driver for an induction motor which includes a voltage limiter, a low-frequency limiter, a forward rotation limiter, a reverse rotation limiter and an overload detector.

[0007] Document WO 2016 / 068 194 A1 discloses a vehicle energy supply control device which is designed to supply and disconnect electrical energy to or from a consumer by switching on or off a semiconductor switching device on an electrical line for supplying electrical energy from a power supply to the consumer based on a temperature of the electrical line. Overview of the invention

[0008] Document JP 2005 - 102 409 A detects an anomaly in relation to the motor drive device when a single motor is driven by a motor drive device, and a case in which a motor drive anomaly is detected when a single motor is driven by a plurality of motor drive devices is not considered.

[0009] Therefore, the objective of the present invention is to provide an anomaly diagnostic device and an anomaly diagnostic method that enable the detection of a drive anomaly of a single motor driven by a plurality of motor drive devices.

[0010] The invention is defined by the main claim and the dependent claim 8.

[0011] According to the present invention, a drive anomaly of a single motor driven by a plurality of motor drive devices can be detected using a simple embodiment.

[0012] The above and other objectives, features and advantages of the present invention will become more apparent from the following description together with the accompanying drawings, in which preferred embodiments of the present invention are illustrated by way of example. Brief description of the drawings Fig. Figure 1 is a schematic graphical representation of one implementation of an anomaly detection system; Fig. 2 is a graphical representation that illustrates the execution of a process in Fig. 1 shows the motor drive device; Fig. 3 is a graphical representation that illustrates the execution of a process in Fig. The anomaly diagnostic device shown in Figure 1 is shown; Fig. 4 is a flowchart that outlines the processes of the in Fig. The anomaly diagnostic device shown in Figure 1 is shown; Fig. Figure 5 is a schematic graphical representation of an implementation of an anomaly diagnosis system according to a second modification; and Fig. Figure 6 is a graph that represents a relationship between a threshold TH and an absolute value of a rotational speed value in the case where the threshold TH changes depending on the absolute value of the rotational speed value. Description of the embodiments

[0013] The following describes embodiments of an anomaly diagnostic device and an anomaly diagnostic procedure with reference to the accompanying drawings.

[0014] Fig. Figure 1 is a schematic graphical representation of an embodiment of an anomaly diagnostic system 10. The anomaly diagnostic system 10 is equipped with a numerical control unit 12, a plurality of motor drive devices 14, a motor 16, a speed detection unit 18, current detection units 20 and an anomaly diagnostic device 22.

[0015] According to the present embodiment, for the sake of simplicity, it is assumed that there are two motor drive devices 14 and that the rotational speed of a single motor 16 is controlled by means of the two motor drive devices 14. Furthermore, to distinguish the two motor drive devices 14 from each other, in certain cases one of the motor drive devices 14 can be represented by 14a and the other by 14b.

[0016] Motor 16 is a synchronous motor. Corresponding to the two motor drive devices 14 (14a, 14b), motor 16 has two three-phase windings (hereinafter referred to as three-phase windings) 17, comprising phase U, phase V, and phase W. In certain cases, the three-phase winding 17 corresponding to motor drive device 14a is referred to as the first three-phase winding (winding) 17a, and the three-phase winding 17 corresponding to motor drive device 14b is referred to as the second three-phase winding (winding) 17b. The first three-phase winding 17a and the second three-phase winding 17b are arranged on a stator of motor 16. Accordingly, it is possible to increase the power (torque) of motor 16. The two motor drive devices 14 (14a, 14b) and the two three-phase windings 17 (17a, 17b) are connected by three-phase alternating current conductors L (L1, L2).According to the present embodiment, the motor 16 is a synchronous motor; however, the motor 16 can be a different type of motor than a synchronous motor (for example, an induction motor).

[0017] To control the motor 16, the numerical control unit 12 issues a speed command or a position command to the two motor drive devices 14 (14a, 14b). According to the present embodiment, the numerical control unit 12 is assumed to issue a speed command to the two motor drive devices 14 (14a, 14b). The speed command is subsequently represented by Vec.

[0018] The two motor drive devices 14 (14a, 14b) apply voltages to the three-phase windings 17 (17a, 17b) of the motor 16 based on the speed command Vec, thereby supplying the first three-phase winding 17a and the second three-phase winding 17b with three-phase alternating currents. As a result, the motor 16 is rotated (driven). The motor drive device 14a supplies the first three-phase winding 17a of the motor 16 with a three-phase alternating current via the lead wire L1, while the motor drive device 14b supplies the second three-phase winding 17b of the motor 16 with a three-phase alternating current via the lead wire L2.

[0019] The speed sensing unit 18 is a sensor that detects a speed value (a rotational speed value of a rotating axis) Ved of the motor 16. The speed sensing unit 18 is formed by a rotary encoder or the like. The current sensing units 20 are provided on each of the line wires L (L1, L2) and detect values ​​Id (Iu, Iv, Iw) of three-phase alternating currents with which the motor 16 is supplied by each of the two motor drive devices 14 (14a, 14b). In certain cases, the current sensing unit 20 that detects the value Id (Id1) of the three-phase alternating current flowing through the first three-phase winding 17a can be represented by 20a, and the current sensing unit 20 that detects the value Id (Id2) of the three-phase alternating current flowing through the second three-phase winding 17b can be represented by 20b. Iu indicates the phase current value of phase U, Iv indicates the phase current value of phase V, and Iw indicates the phase current value of phase W.The phase current values ​​Iu, Iv and Iw satisfy the relationship Iu + Iv + Iw = 0.

[0020] The two motor drive devices 14 (14a, 14b) control the motor 16 using the speed value Ved detected by the speed detection unit 18 and the three-phase alternating current values ​​Id (Id1, Id2) detected by the current detection units 20 (20a, 20b).

[0021] The anomaly diagnostic device 22 checks whether the operation of the motor 16 is normal. Cases in which the operation of the motor 16 is anomalous include, for example, a case in which the motor 16 is operated in a state where at least one phase of the three-phase winding 17 is interrupted. For example, the anomaly diagnostic device 22 detects that the operation of the motor 16 is anomalous if at least one phase of the first three-phase winding 17a is interrupted and the motor 16 is operated, or if at least one phase of the second three-phase winding 17b is interrupted and the motor 16 is operated.

[0022] Based on the rotational speed value Ved detected by the speed detection unit 18 and the three-phase alternating current values ​​Id (Id1, Id2) detected by the two current detection units 20 (20a, 20b), the anomaly diagnostic device 22 determines whether the drive of the motor 16 is proceeding normally. The anomaly diagnostic device 22 is described in detail below.

[0023] Fig. Figure 2 is a graphical representation showing the design of a motor drive device 14a. Since the motor drive device 14b has the same design as the motor drive device 14a, the motor drive device 14a is described representatively. The motor drive device 14a is equipped with a torque command generation unit 30, a current command generation unit 32, a voltage command generation unit 34, and a power supply unit 36.

[0024] The torque command generation unit 30 generates (calculates) a torque command value Tc based on the speed command Vec issued by the numerical control unit 12. The torque command generation unit 30 generates the torque command value Tc using the rotational speed value Ved, which is a feedback value detected by the rotational speed sensing unit 18. More precisely, the torque command generation unit 30 calculates the torque command value Tc based on the difference between the speed command Vec and the rotational speed value Ved. The torque command generation unit 30 outputs the generated (calculated) torque command value Tc to the current command generation unit 32.

[0025] The current command generation unit 32 generates (calculates) a current command value Ic based on the torque command value Tc, which is transmitted to the torque command generation unit 30. The current command generation unit 32 outputs the generated (calculated) current command value Ic to the voltage command generation unit 34.

[0026] The voltage command generation unit 34 generates (calculates) a voltage command value Vc1 based on the current command value Ic, which is transmitted to it by the current command generation unit 32. The voltage command generation unit 34 generates the voltage command value Vc1 using the three-phase alternating current value Id1 (Iu, Iv, Iw), which is a feedback value detected by the current sensing unit 20a.

[0027] More precisely, the voltage command generation unit 34 generates the voltage command value Vc1 in such a way that the three-phase AC current value Id1 (Iu, Iv, Iw) detected by the current sensing unit 20a becomes a three-phase AC current corresponding to the three-phase AC command value Ic. The voltage command generation unit 34 outputs the generated (calculated) voltage command value Vc1 to the power supply unit 36.

[0028] The power supply unit 36 ​​serves as a driver for driving the motor 16 and includes, for example, an inverter circuit or the like, which converts the current supplied by the power supply into three-phase alternating current. The power supply unit 36 ​​supplies the first three-phase winding 17a with the three-phase alternating current by applying a voltage to the first three-phase winding 17a of the motor 16 based on the voltage command value Vc1. As a result, the motor 16 is driven.

[0029] Furthermore, in the case of the motor drive device 14b, the voltage command generation unit 34 generates the voltage command value Vc2 using the three-phase alternating current value Id2 (Iu, Iv, Iw), which is a feedback value detected by the current sensing unit 20b. The power supply unit 36 ​​also supplies the second three-phase winding 17b of the motor 16 with the three-phase alternating current based on the voltage command value Vc2.

[0030] Fig. Figure 3 is a graphical representation showing the design of the anomaly diagnostic device 22. The anomaly diagnostic device 22 is formed by a computer comprising a processor, such as a central processing unit (CPU), and a storage medium. The anomaly diagnostic device 22 is equipped with a power harvesting unit 40, a speed harvesting unit 42, a detection unit 44, a notification unit 46, and a drive stop unit 48.

[0031] The power generation unit 40 acquires the value Id1 (Iu, Iv, Iw) of the three-phase alternating current flowing through the three-phase winding 17a, which is detected by the current sensing unit 20a, and the value Id2 (Iu, Iv, Iw) of the second three-phase alternating current flowing through the second three-phase winding 17b, which is detected by the current sensing unit 20b. The power generation unit 40 outputs the acquired three-phase alternating current values ​​Id1 and Id2 to the detection unit 44.

[0032] The speed acquisition unit 42 acquires the speed value Ved of the motor 16, as recorded by the speed detection unit 18. The speed acquisition unit 42 outputs the acquired speed value Ved to the determination unit 44.

[0033] The detection unit 44 includes a clock circuit that measures or clocks the passage of time. The clock circuit increments a counter value C in a predefined cycle, thus enabling the timing of the passage of time. Using the value Id1 of the three-phase alternating current flowing through the first three-phase winding 17a, the detection unit 44 determines whether at least one phase of the first three-phase winding 17a is interrupted. Furthermore, using the value Id2 of the three-phase alternating current flowing through the second three-phase winding 17b, the detection unit 44 determines whether at least one phase of the second three-phase winding 17b is interrupted. The detection unit 44 determines that the operation of the motor 16 is anomalous if it is determined that at least one phase of at least one of the three-phase windings 17, the first three-phase winding 17a and / or the second three-phase winding 17b, is interrupted.

[0034] More precisely, the investigation unit 44 determines that the operation of the motor 16 is anomalous if, over a specified period, the absolute value of the speed value Ved continuously exceeds the specified value SV (|Ved| > SV) and the absolute value of the phase current of any phase, among the values ​​Id (Id1, Id2) of the alternating current flowing through the respective three-phase windings 17 (17a, 17b), is less than the threshold value TH (|Iu| < TH, |Iv| < TH or |Iw| < TH). In this case, the phase of the respective three-phase windings 17 (17a, 17b) for which the absolute value of the phase current is less than the threshold value TH is interrupted.

[0035] The reason for determining whether the absolute value of the speed value Ved exceeds the specified value SV is that the speed of motor 16 decreases when the voltage command value Vc is small, and there is a possibility that the anomaly detection cannot be performed correctly.

[0036] Furthermore, the reason for determining whether the absolute value of the phase current of any one of the three-phase windings 17 (17a, 17b) is less than the threshold TH is that the phase current of the interrupted phase is constantly 0 (zero) when the phase of any one of the three-phase windings 17 (17a, 17b) is interrupted. Moreover, the phase currents of the respective phases of the three-phase windings 17 (17a, 17b) all become equal to 0 (zero) when two phases of the three-phase windings 17 (17a, 17b) are interrupted.

[0037] The reason for determining whether the specified time period has elapsed is determined when the absolute value of the speed value Ved exceeds the specified value SV and the phase current value of any phase of the three-phase windings 17 (17a, 17b) is less than the threshold value TH, is that the phase current values ​​Iu, Iv, Iw of the respective phases fluctuate over time and therefore there may be cases in which the phase current values ​​Iu, Iv, Iw become less than the threshold value TH, even if there has been no interruption.

[0038] Furthermore, the investigation unit 44 can determine that the driving of the motor 16 is anomalous if the absolute value of the speed value Ved exceeds the specified value SV, the absolute value of the phase current value of any phase of the three-phase windings 17 (17a, 17b) is less than the threshold value TH, and the absolute value of a sum of the phase current values ​​of the remaining phases is less than the threshold value TH.

[0039] For example, if the absolute value of the phase current Iu is less than the threshold TH (|Iu| < TH), or if the absolute value of the sum of the phase currents Iv and Iw of the other phases is less than the threshold TH (|Iv + Iw| < TH), the detection unit 44 can determine that the drive of motor 16 is anomalous. In this case, the relationship |Iu| = |Iv + Iw| from the relational expression Iu + Iv + Iw = 0 is satisfied. Accordingly, in the case of |Iu| < TH, although |Iv + Iw| < TH is also satisfied, a confirmation check is also performed to ensure that the absolute value of the sum of the other phase currents is consistently less than the threshold TH over a specified period.

[0040] If the investigation unit 44 determines that the driving of the motor 16 is anomalous, the notification unit 46 and the drive stop unit 48 carry out an alarm process.

[0041] If an anomalous operation of the motor 16 is detected, the notification unit 46 issues a notification alarm to the operator as an alarm process. The notification unit 46 may have a display unit (not illustrated) and may issue a notification by displaying a warning message on the display unit. Furthermore, the notification unit 46 may have a loudspeaker (not illustrated) or a light-emitting unit and may issue a notification alarm by sound or light. The notification unit 46 may also display the notification alarm on a display unit of the numeric control unit 12. Finally, the notification unit 46 may issue the notification alarm using an externally provided loudspeaker or by causing light to be emitted by an externally provided light-emitting unit.

[0042] If an anomalous driving of motor 16 is detected, the drive stop unit 48, as an alarm process, stops the driving of motor 16 by the two motor drive devices 14 (14a, 14b). When the anomalous driving of motor 16 is detected, the drive stop unit 48 stops the driving of motor 16 by outputting a stop signal to the two motor drive devices 14 (14a, 14b). When the stop signal is transmitted there, the two motor drive devices 14 (14a, 14b) stop the power supply to motor 16. For example, the voltage command generation unit 34 can stop the power supply to motor 16 by preventing the output of the voltage command values ​​Vc (Vc1, Vc2) to the power supply unit 36.

[0043] Furthermore, according to the present embodiment, both the alarm notification and the stopping of the motor 16's operation are carried out when it is determined that the motor 16's operation is proceeding anomalously. However, only one such process may be carried out as an alarm process.

[0044] Next, the procedures of the anomaly detection device 22 will be described with reference to the one in Fig. The process described in section 4 is explained in the following flowchart. Fig. The processes shown in Figure 4 are executed in a predefined cycle. Furthermore, it is assumed that the speed detection unit 18 and the current detection units 20 (20a, 20b) detect the speed value Ved and the AC current values ​​Id (Id1, Id2) in a cycle that is less than or equal to the predefined cycle.

[0045] In step S1, the determination unit 44 determines whether the absolute value of the rotational speed value Ved obtained by the rotational speed acquisition unit 42 is greater than the specified threshold value SV (|Ved| > SV?).

[0046] If step S1 determines that the absolute value of the rotational speed Ved is less than or equal to the specified value SV, the process proceeds to step S2. Conversely, if step S1 determines that the absolute value of the rotational speed Ved is greater than the specified value SV, the process proceeds to step S3.

[0047] When moving to step S2, the investigation unit 44 resets the count value C to zero (C = 0), and then the current processes are completed.

[0048] Upon proceeding to step S3, the detection unit 44 determines whether the absolute value of the phase current Iu of phase U is less than the threshold TH (|Iu| < TH?). If step S3 determines that the absolute value of the phase current Iu of phase U is less than the threshold TH, the process proceeds to step S4.

[0049] When moving to step S4, the determination unit 44 determines whether the absolute value of the sum of the phase current values ​​Iv, Iw of phase V and phase W is less than the threshold value TH (|Iv + Iw| < TH?).

[0050] If step S4 determines that the absolute value of the sum of the phase current values ​​Iv, Iw of phase V and phase W is greater than or equal to the threshold value TH, the process proceeds to step S2. Conversely, if step S4 determines that the absolute value of the sum of the phase current values ​​Iv, Iw of phase V and phase W is less than the threshold value TH, the process proceeds to step S5.

[0051] If in step S3 it is determined that the absolute value of the phase current value Iu of phase U is greater than or equal to the threshold value TH, the process proceeds to step S6, whereupon the detection unit 44 determines whether the absolute value of the phase current value Iv of phase V is less than the threshold value TH (|Iv| < TH?).

[0052] If in step S6 it is determined that the absolute value of the phase current value Iv of phase V is less than the threshold value TH, the process proceeds to step S7, whereupon the determination unit 44 determines whether the absolute value of the sum of the phase current values ​​Iw, Iu of phase W and phase U is less than the threshold value TH (|Iw + Iu| < TH?).

[0053] If step S7 determines that the absolute value of the sum of the phase current values ​​Iw, Iu of phase W and phase U is greater than or equal to the threshold value TH, the process proceeds to step S2. Conversely, if step S7 determines that the absolute value of the sum of the phase current values ​​Iw, Iu of phase W and phase U is less than the threshold value TH, the process proceeds to step S5.

[0054] If in step S6 it is determined that the absolute value of the phase current value Iv of phase V is greater than or equal to the threshold value TH, the process proceeds to step S8, whereupon the determination unit 44 determines whether the absolute value of the phase current value Iw of phase W is less than the threshold value TH (|Iw| < TH?).

[0055] If step S8 determines that the absolute value of the phase current Iw of phase W is greater than or equal to the threshold TH, the process proceeds to step S2. Conversely, if step S8 determines that the absolute value of the phase current Iw of phase W is less than the threshold TH, the process proceeds to step S9.

[0056] Upon proceeding to step S9, the detection unit 44 determines whether the absolute value of the sum of the phase current values ​​Iu and Iv of phase U and phase V is less than the threshold value TH (|Iu + Iv| < TH?). If step S9 determines that the absolute value of the sum of the phase current values ​​Iu and Iv of phase U and phase V is greater than or equal to the threshold value TH, the process proceeds to step S2. Conversely, if step S9 determines that the absolute value of the sum of the phase current values ​​Iu and Iv of phase U and phase V is less than the threshold value TH, the process proceeds to step S5.

[0057] When transitioning to step S5, the detection unit 44 increments the count value C (C = C + 1). In other words, the detection unit 44 increments the count value C if the absolute value of the phase current value Iu is less than the threshold value TH and the absolute value of the sum of the phase current values ​​Iv, Iw is less than the threshold value TH; or if the absolute value of the phase current value Iw is less than the threshold value TH and the absolute value of the sum of the phase current values ​​Iu, Iv is less than the threshold value TH.

[0058] Next, in step S10, the investigation unit 44 determines whether the electricity meter reading C is greater than a predefined value C1. In other words, step S10 determines whether a predefined period has elapsed with the states "Yes in steps S1, S3 and S4", "Yes in steps S1, S6 and S7" or "Yes in steps S1, S8 and S9".

[0059] If step S10 determines that the current count value C is less than or equal to the specified value C1, the current operations are completed. Conversely, if step S10 determines that the current count value C is greater than the specified value C1, the detection unit 44 determines that the drive of motor 16 is anomalous, and the process proceeds to step S11.

[0060] When proceeding to step S11, an alarm process is carried out. More precisely, the notification unit 46 issues a notification alarm to the operator, and simultaneously the drive stop unit 48 stops the motor 16 from being driven by the two motor drive devices 14 (14a, 14b).

[0061] Investigation Unit 44 is conducting the investigation in Fig. The processes described in section 4 are carried out based on the three-phase AC current value Id1 (Iu, Iv, Iw) detected by the current sensing unit 20a and on the three-phase AC current value Id2 (Iu, Iv, Iw) detected by the current sensing unit 20b. Accordingly, if any phase of at least one of the three-phase windings 17 is interrupted by the two three-phase windings 17 (17a, 17b), an anomaly is detected and the alarm process is executed.

[0062] In the manner described above, the anomaly diagnostic device 22 determines whether the drive of the motor 16 is anomalous, using the rotational speed value Ved detected by the speed detection unit 18 and the alternating current values ​​Id (Id1, Id2) detected by the current detection units 20 (20a, 20b). Therefore, with a simple design, it is possible to detect a drive anomaly of the individual motor 16, which is driven by the two motor drive devices 14 (14a, 14b). [Modifications]

[0063] The embodiment described above can be modified in the following way. <Modifizierung 1>

[0064] In the embodiment described above, the anomaly diagnostic device 22 is provided separately from the numerical control unit 12 and the motor drive devices 14. However, the anomaly diagnostic device 22 can be formed by the numerical control unit 12. In other words, the anomaly diagnostic device 22 can be provided within the numerical control unit 12. According to this feature, there is no need to provide the anomaly diagnostic device 22 separately, which leads to a reduction in costs.

[0065] The anomaly diagnostic device 22 can also be formed by the motor drive devices 14. In other words, the anomaly diagnostic device 22 can be provided within the motor drive devices 14. In this case, the anomaly diagnostic device 22 can be provided in at least one of the majority of the motor drive devices 14, or it can be provided in all of the majority of the motor drive devices 14. According to this feature, there is no need to provide the anomaly diagnostic device 22 separately, costs can be reduced, and the anomaly diagnosis can be carried out immediately. <Modifizierung 2>

[0066] In the embodiment described above, one anomaly detection device 22 was provided. However, a plurality of anomaly detection devices 22 can be provided, corresponding to the plurality of three-phase windings 17. For example, if the motor 16 has two three-phase windings 17 (17a, 17b), two anomaly detection devices 22 are provided. In this case, the anomaly detection devices 22 can be provided separately from the motor drive devices 14 (14a, 14b) that supply current to the respective three-phase windings 17 (17a, 17b), or they can be provided within the motor drive devices 14 (14a, 14b) that supply current to the respective three-phase windings 17 (17a, 17b).

[0067] Fig. Figure 5 is a graphical representation depicting an anomaly diagnostic system 10 for a case in which a plurality of anomaly diagnostic devices 22 are provided in the motor drive devices 14 (14a, 14b) that supply current to the corresponding three-phase windings 17 (17a, 17b). Fig. 5 the anomaly diagnostic device 22, which is arranged in the motor drive device 14a, which corresponds to the first three-phase winding 17a, is characterized by 22a, whereas the anomaly diagnostic device 22, which is arranged in the motor drive device 14b, which corresponds to the second three-phase winding 17b, is characterized by 22b.

[0068] The detection unit 44 of the anomaly diagnostic device 22a determines whether the drive of the motor 16 is anomalous, based on the AC current value Id1 (Iu, Iv, Iw) detected by the current detection unit 20a. In other words, the anomaly diagnostic device 22a determines whether at least one phase of the first three-phase winding 17a is interrupted, and if it is determined that at least one phase is interrupted, it determines that the drive of the motor 16 is anomalous.

[0069] If the detection unit 44 of the anomaly diagnostic device 22a determines that the drive of motor 16 is anomalous, the drive stop unit 48 of the anomaly diagnostic device 22a stops the drive of motor 16 by the motor drive device 14a, and simultaneously, by sending a stop signal to the motor drive device 14b, the drive of motor 16 by the motor drive device 14b is also stopped. As a result, the drive of motor 16 is stopped.

[0070] Similarly, the detection unit 44 of the anomaly diagnostic device 22b determines whether the drive of the motor 16 is anomalous, based on the AC current value Id2 (Iu, Iv, Iw) detected by the current detection unit 20b. In other words, the anomaly diagnostic device 22b determines whether at least one phase of the second three-phase winding 17b is interrupted, and if it is determined that at least one phase is interrupted, it determines that the drive of the motor 16 is anomalous.

[0071] If the detection unit 44 of the anomaly diagnostic device 22b determines that the drive of motor 16 is anomalous, the drive stop unit 48 of the anomaly diagnostic device 22b stops the drive of motor 16 by the motor drive device 14b, and simultaneously, by sending a stop signal to the motor drive device 14a, the drive of motor 16 by the motor drive device 14a is also stopped. As a result, the drive of motor 16 is stopped.

[0072] By providing the majority of anomaly diagnostic devices (22) in the motor drive devices 14 (14a, 14b) that supply current to the corresponding three-phase windings 17 (17a, 17b), costs can be reduced and at the same time it can be made possible to carry out the anomaly diagnosis immediately. <Modifizierung 3>

[0073] In the embodiment described above and in modifications 1 and 2, the threshold TH is constant; however, the threshold TH can be changed. For example, the detection unit 44 causes the threshold TH to increase when the absolute value of the rotational speed Ved increases. This is because, when the absolute value of the rotational speed Ved is small, the alternating current supplying the three-phase windings 17 also becomes small. This feature makes it possible to correctly determine which of the phases of the three-phase windings 17 is interrupted.

[0074] Fig. Figure 6 is a graph that, in modification 3, represents a relationship between the threshold value TH and the absolute value of the rotational speed value Ved. As in Fig. As shown in Figure 6, the threshold TH gradually increases along with an increase in the absolute value of the rotational speed value Ved until the absolute value of the rotational speed value Ved reaches a certain value, and when the absolute value of the rotational speed value Ved reaches the certain value, the threshold TH becomes constant. Furthermore, in Fig. 6. The threshold TH is not displayed at a time when the absolute value of the rotational speed Ved is less than the specified value SV. The reason for this is that the process is set to "No" in step S1 of Fig. 4 branches off if the absolute value of the rotational speed value Ved is less than or equal to the specified value SV, and therefore the anomaly detection is not performed (the threshold value TH is not used). <Modifizierung 4>

[0075] In the embodiment described above and in modifications 1 to 3, the numerical control unit 12 outputs the speed value Vec to the two motor drive devices 14 (14a, 14b). However, the speed value Vec can also be output to only one of the motor drive devices 14. Furthermore, in the description of modification 4, the motor drive device 14 into which the speed command Vec is input is 14a, and the motor drive device 14 into which the speed command Vec is not input is 14b.

[0076] Furthermore, the motor drive unit 14a outputs the torque command value Tc, generated based on the speed value Vec, or the current command value Ic, generated based on the torque command value Tc, to the motor drive unit 14b. When the torque command value Tc is input to the motor drive unit 14b, the current command generation unit 32 of the motor drive unit 14b generates the current command value Ic based on the input torque command value Tc. Furthermore, when the current command value Ic is input to the motor drive unit 14b, the voltage command generation unit 34 of the motor drive unit 14b generates the voltage command value Vc2 based on the input current command value Ic and the AC current value Id2, which is a feedback value.

Claims

[1] Anomaly diagnostic device (22) designed to detect a drive anomaly of a single motor (16) driven by a plurality of motor drive devices (14); wherein the majority of motor drive devices (14) drive the motor (16) by supplying a majority of three-phase windings (17) which the motor (16) has with a three-phase alternating current; the anomaly detection device (22) comprises: a speed acquisition unit (42) designed to acquire a speed value (Ved) of the motor (16); a power generation unit (40) configured to obtain values ​​of phase currents from the respective phases flowing through the three-phase windings (17); and a detection unit (44) which is designed to determine whether an absolute value of the rotational speed (Ved) exceeds a predetermined value (SV) and to determine, if an absolute value of the rotational speed (Ved) exceeds the predetermined value (SV) and if an absolute value of the phase current of any phase of the three-phase windings (17) is less than a threshold value (TH) over a predetermined period, that an anomaly exists in which the phase of the three-phase windings (17) is interrupted, and wherein the determination unit (44) changes the threshold value (TH) depending on a size of the absolute value of the rotational speed value (Ved). [2] Anomaly diagnostic device (22) according to claim 1, wherein the detection unit (44) determines that an anomaly is present if, over a predetermined period, the absolute value of the rotational speed value (Ved) continuously exceeds a predetermined value (SV), an absolute value of the phase current value of any phase of the three-phase windings (17) is less than the threshold value (TH), and an absolute value of a sum of the phase current values ​​of other phases is less than the threshold value TH. [3] Anomaly diagnostic device (22) according to any one of claims 1 to 2, which further comprises a notification unit (46) configured to issue a notification alarm when the presence of an anomaly is detected by the detection unit (44). [4] Anomaly diagnostic device (22) according to any one of claims 1 to 3, which further comprises a drive stop unit (48) configured to stop the driving of the motor (16) by the plurality of motor drive devices (14) when the presence of an anomaly is detected by the detection unit (44). [5] Anomaly diagnostic device (22) according to any one of claims 1 to 4, wherein the anomaly diagnostic device (22) is provided in the motor drive device (14). [6] Anomaly diagnostic device (22) according to any one of claims 1 to 5, wherein: a majority of the anomaly diagnostic devices (22) are provided corresponding to the majority of three-phase windings (17); and Each of the plurality of anomaly diagnostic devices (22) determines, on the basis of the phase current values ​​of respective phases of the corresponding three-phase windings (17), whether the driving of the motor (16) is anomalous. [7] Anomaly diagnostic device (22) according to any one of claims 1 to 5, wherein: the power generation unit (40) obtains the values ​​of the phase currents of respective phases flowing through each of the plurality of three-phase windings (17); and The investigation unit (44) determines, on the basis of the values ​​of the phase currents of the respective phases flowing through each of the plurality of three-phase windings (17), whether the driving of the motor (16) is anomalous. [8] Anomaly diagnostic method for detecting a drive anomaly of a single motor (16) driven by a plurality of motor drive devices (14); wherein the majority of motor drive devices (14) drive the motor (16) by supplying a majority of three-phase windings (17) which the motor (16) has with a three-phase alternating current; the anomaly diagnosis procedure exhibits: a speed gain step to obtain a speed value (Ved) of the motor (16); a power generation step to obtain values ​​of phase currents of respective phases flowing through the three-phase windings (17); and a determination step to ascertain whether an absolute value of the rotational speed (Ved) exceeds a predetermined value (SV) and to determine, if an absolute value of the rotational speed (Ved) exceeds the predetermined value (SV) and if an absolute value of the phase current of any phase of the three-phase windings (17) is less than a threshold value (TH) over a predetermined period, that an anomaly exists in which the phase of the three-phase windings (17) is interrupted, and wherein In the determination step, the threshold value (TH) is changed depending on a size of the absolute value of the rotational speed value (Ved). [9] Anomaly diagnosis method according to claim 8, wherein in the determination step it is determined that an anomaly exists if, over a predetermined period, the absolute value of the rotational speed value (Ved) continuously exceeds a predetermined value (SV), an absolute value of the phase current value of any phase of the three-phase windings (17) is less than the threshold value (TH), and an absolute value of a sum of the phase current values ​​of other phases is less than the threshold value TH. [10] Anomaly diagnosis method according to any one of claims 8 to 9, further comprising a notification step for issuing a notification alarm when the presence of an anomaly is determined by the detection step. [11] Anomaly diagnosis method according to any one of claims 8 to 10, further comprising a drive stop step for stopping the driving of the motor (16) by the plurality of motor drive devices (14) when the presence of an anomaly is determined by the detection step. [12] Anomaly diagnosis method according to any one of claims 8 to 11, wherein: the anomaly diagnosis procedure is implemented by each of the plurality of motor drive devices (14); and In the investigation step, based on the phase current values ​​of the respective phases of the three-phase windings (17), which are supplied with the three-phase alternating current by their own motor drive device (14), it is determined whether the driving of the motor (16) is anomalous. [13] Anomaly diagnosis method according to any one of claims 8 to 11, wherein: in the power generation step the values ​​of the phase currents of respective phases flowing through each of the plurality of three-phase windings (17) are obtained; and In the investigation step, based on the values ​​of the phase currents of the respective phases flowing through each of the plurality of three-phase windings (17), it is determined whether the driving of the motor (16) is anomalous.

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