MOTOR CONTROL DEVICE AND METHOD FOR DETECTING ABNORMALITY IN CURRENT DETECTOR PROVIDED IN THE MOTOR CONTROL DEVICE

Abstract

To provide a motor control device in which a malfunction in a current detector can be detected with higher precision.SOLUTION: A motor control device includes a malfunction determining unit that determines whether a malfunction has occurred in a current detector. The malfunction determining unit calculates, as a voltage command threshold Ea, a value obtained by adding a dead time voltage error Edt which is generated due to a dead time Td to an ideal voltage command threshold Eir which is obtained by multiplying a prescribed reference current value Idef and a motor resistance value. When the effective value of the voltage command value is equal to or greater than the voltage command threshold Ea and the effective value of the current detection value is equal to or less than a current detection threshold Ia which is less than the reference current value Idef, the malfunction determining unit outputs a signal for indicating a malfunction in a current detector 7, 8.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] This specification discloses a motor control device that applies a voltage to a three-phase motor by PMW control, and a method for detecting an abnormality in a current detector provided in the motor control device. [Background technology]

[0002] Motor control devices used in machine tools and the like protect motors, inverters, etc. from overcurrent based on current detection values. If there is an abnormality in the current detector, it will no longer be possible to detect and protect against overcurrent, so various methods of detecting abnormalities in the current detector have been devised.

[0003] For example, if current detectors are installed on all power lines, the sum of the three-phase AC currents of the U phase, V phase, and W phase is zero, so that an abnormality in the current detector can be easily detected.

[0004] Furthermore, even if a current detector is provided for only one phase, an abnormality in the current detector for that phase can be detected by utilizing the fact that the voltage value is the product of the current value and the motor resistance value.

[0005] Patent Document 1 discloses a method for detecting an abnormality in a current detector from two-phase current detection values. By utilizing the fact that three phases of a fixed coordinate system rotate relatively on the dq-axis plane, which is a rotating coordinate system, and controlling the motor drive from a one-phase current detection value, it is possible to detect an abnormality in the current detector while avoiding the influence of feedback due to current control.

[0006] In Patent Document 2, it is possible to detect an abnormality in a current detector when the motor is not rotating by detecting the voltage fluctuation of the DC voltage before PWM control output by the converter when the current detection value is 0. In addition, since the abnormality is detected based on the current detection value of each current detector, it is also possible to identify the current detector in which the abnormality has occurred. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2014-73009 A [Patent Document 2] JP 2001-157460 A Summary of the Invention [Problem to be solved by the invention]

[0008] In motor drive devices used in machine tools, etc., if an abnormality occurs in the current detector while the motor is rotating, the motor will not be able to follow commands, and some kind of abnormality will be detected. However, if the rotor is in a specific position while the motor is stopped, there will be a phase in which the motor will not rotate even if current is passed through it. In such a case, if the current detection value becomes 0 due to an abnormality in the current detector, the command voltage will increase without other abnormalities being detected, and an overcurrent will flow through the motor or power lines, which may cause them to burn out. Therefore, it is necessary to detect abnormalities in the current detector while the motor is stopped.

[0009] To detect anomalies in a current detector, it is necessary to install a current detector on every electric wire, taking advantage of the fact that the sum of the three phases of the three-phase AC current, U, V, and W, is zero. However, if the motor drive control is performed based on the current detection values ​​of two phases, taking advantage of the fact that the sum of the three phases of the three-phase AC current is zero, the need to add more current detectors leads to higher costs and larger equipment.

[0010] In addition, when detecting an abnormality in the current detector by utilizing the voltage value obtained by multiplying the current value and the motor resistance value, the dead-time voltage error is not taken into consideration. Therefore, if the dead-time voltage error is large, a false detection will occur in which the current detector is judged to be abnormal even when there is no abnormality. If a margin is set to avoid false detection, there is a problem that if the dead-time voltage error is small, an abnormality cannot be detected quickly even if it occurs, resulting in a detection miss.

[0011] In Patent Document 1, since the three phases of a fixed coordinate system rotate relatively on the dq-axis plane, which is a rotating coordinate system, it is not possible to detect an abnormality in a current detector while the motor is stopped. Also, it is not possible to identify the current detector in which an abnormality has occurred.

[0012] In Patent Document 2, an abnormality in a current detector is detected by a voltage fluctuation in the DC voltage output by the converter when the current detection value is 0, so that an abnormality can be detected even when the motor is stopped. However, industrial machines such as machine tools generally use multiple motors, and multiple motor control devices may be connected to one converter. In this case, voltage fluctuation occurs due to the influence of the other motors being driven, so if the target motor is stopped and another motor connected to the same converter is operating, an erroneous detection will occur. [Means for solving the problem]

[0013] The motor control device disclosed in this specification is a motor control device that controls the driving of a three-phase motor, and includes a current control unit that outputs a voltage command value for each of the three phases, a PWM control unit that converts a DC voltage output from a converter into an AC voltage by modulating a switching pulse width in accordance with the voltage command value, and applies the AC voltage to each of the three power lines of the three-phase motor, one or more current detectors that are provided in at least one of the three power lines and detect a current value flowing through the power line as a current detection value, and an abnormality judgment unit that judges whether or not the current detector is abnormal, wherein the abnormality judgment unit calculates, as a voltage command threshold, a value obtained by multiplying a specified reference current value and a motor resistance value and adding a dead time voltage error, which is a voltage error caused by the dead time of the switching, to an ideal voltage command threshold, which is a value obtained by multiplying a specified reference current value and a motor resistance value, and outputs a signal indicating an abnormality in the current detector when the effective value of the voltage command value is equal to or greater than the voltage command threshold and the effective value of the current detection value is equal to or less than a current detection threshold, which is a value lower than the reference current value.

[0014] In this case, the abnormality determination unit may calculate, as the dead-time voltage error, a value obtained by multiplying the dead time by a carrier frequency and a power supply voltage value of the DC voltage.

[0015] Moreover, the current control unit may have a deadtime compensator that outputs, as the voltage command value for each of the three phases, a value obtained by adding a deadtime compensation value to a pre-compensation voltage command value for each of the three phases calculated based on a torque command value, and the deadtime compensator may calculate a specified deadtime compensation voltage parameter as the deadtime compensation value when the current command value exceeds a specified deadtime compensation current parameter, and may calculate, as the deadtime compensation value, a value obtained by multiplying the deadtime compensation voltage parameter by a ratio of the current command value to the deadtime compensation current parameter when the current command value is equal to or smaller than the deadtime compensation current parameter.

[0016] The abnormality determination unit determines whether or not the dead time is ,tree The dead-time voltage error may be calculated by multiplying a carrier frequency and a power supply voltage value of the DC voltage. The abnormality determination unit may calculate the dead-time compensation voltage parameter as the dead-time voltage error.

[0017] The abnormality determination unit determines whether or not the dead time is ,tree A value obtained by multiplying a carrier frequency and a power supply voltage value of the DC voltage may be calculated as a dead-time voltage error calculation value, and the larger of the dead-time compensation voltage parameter and the dead-time voltage error calculation value may be calculated as the dead-time voltage error.

[0018] The abnormality determination unit determines whether or not the dead time is ,tree A value obtained by multiplying a carrier frequency and a power supply voltage value of the DC voltage may be calculated as a dead-time voltage error calculation value, and the smaller of the dead-time compensation voltage parameter and the dead-time voltage error calculation value may be calculated as the dead-time voltage error.

[0019] The method for detecting an abnormality in a current detector disclosed in this specification calculates a voltage command threshold value by adding a dead-time voltage error, which is a voltage error caused by a dead time of switching for applying a voltage to the motor, to an ideal voltage command threshold value, which is a value obtained by multiplying a specified reference current value and a resistance value of a motor. , the motor power the effective value of the voltage command value is equal to or greater than the voltage command threshold value, and the effective value of the current detection value detected by the current detector is lower than the reference current value. R When the detected current is equal to or less than a current detection threshold, a signal indicating an abnormality in the current detector is output. Effect of the Invention

[0020] According to the technology disclosed in this specification, abnormalities are judged using the voltage command values ​​and current detection values ​​of each phase, as well as a threshold value that takes into account the dead-time voltage error, so that abnormalities can be detected quickly and before excessive current flows, without erroneous detection. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a block diagram showing a configuration of a motor control device. [Diagram 2] FIG. 4 is a diagram showing an example of current-voltage characteristics. [Diagram 3] FIG. 2 is a block diagram showing another example of the configuration of the motor control device. [Figure 4] FIG. 4 is a diagram showing the configuration of a U-phase abnormality determiner. [Diagram 5] FIG. 2 is a block diagram showing another example of the configuration of the motor control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] FIG. 1 shows a block diagram of a motor control device. A converter 5 receives a three-phase AC power supply 6 as an input and outputs a DC voltage with a power supply voltage value Ep. One or more motor control devices 100 (two in the illustrated example) are connected to the converter 5. The motor control device 100 includes a current control unit 1 that calculates a voltage command value for driving a three-phase motor with a torque command value output by a higher-level control device (not shown), a converter 5 that receives a three-phase AC power supply 6 as an input and outputs a DC voltage with a power supply voltage value Ep, a PWM control unit 2 that converts a DC voltage into a three-phase AC voltage by modulating a switching pulse width according to the voltage command value and applies the converted voltage to a motor power line, a current detector 7 that detects a U-phase current, a current detector 8 that detects a V-phase current, a U-phase abnormality determiner 9 that detects an abnormality in the current detector 7, and a V-phase abnormality determiner 10 that detects an abnormality in the current detector 8. The current control unit 1, the PWM control unit 2, the U-phase abnormality determiner 9, and the V-phase abnormality determiner 10 may be physically configured as a computer having a processor and a memory, or may be configured as an electric circuit. The PWM control unit 2 performs pulse width modulation using a carrier wave with a predetermined carrier frequency Fca. A predetermined dead time Td is provided for switching.

[0023] The U-phase anomaly determiner 9 and the V-phase anomaly determiner 10 use a voltage command threshold Ea and a current detection threshold Ia based on the current-voltage characteristics to determine an anomaly in the current detector from the voltage command value and the current detection value. In PWM control, a voltage error occurs due to dead time, so the current-voltage characteristics are as shown by the solid line in Figure 2. The dashed line in Figure 2 shows the ideal current-voltage characteristics when there is no dead time, where the voltage value is the product of the current value and the motor resistance value. It is widely known that the dead time voltage error Edt is the product of the dead time Td multiplied by the carrier frequency Fca and the power supply voltage value Ep. In other words, Edt = Td x Fca x Ep.

[0024] When the U-phase voltage command effective value is equal to or greater than a predetermined voltage command threshold value Ea and the U-phase current detection effective value is equal to or less than a predetermined current detection threshold value Ia, the U-phase abnormality determiner 9 determines that an abnormality has occurred in the current detector 7 and outputs a U-phase current detector abnormality signal to a higher-level control device (not shown). The V-phase abnormality determiner 10 also performs similar processing.

[0025] The voltage command threshold Ea and the current detection threshold Ia are set based on a predetermined reference current Idef. The value of the reference current Idef is not particularly limited as long as it is smaller than the maximum allowable current. Therefore, for example, the rated current Ir that can be continuously passed may be used as the reference current Idef.

[0026] The voltage command threshold Ea is the actual voltage value when this reference current Idef flows. For example, if the rated current Ir is the reference current Idef, the voltage value when this rated current Ir flows is theoretically the rated current Ir multiplied by the motor resistance value, which is the ideal voltage command threshold Eir in FIG. 2. However, in reality, since a dead-time voltage error Edt exists, the actual voltage value when the rated current Ir flows is the ideal voltage command threshold Eir plus the dead-time voltage error Edt. Therefore, in this example, the voltage command threshold Ea is calculated by the formula (1). When such a value is used as the voltage command threshold Ea, an abnormality in the current detectors 7 and 8 can be detected promptly before a current equal to or greater than the rated current Ir flows. Ea = Eir + Edt (1)

[0027] The current detection threshold Ia is not particularly limited as long as it is a value lower than the reference current Idef. In other words, in this example, a value lower than the current that should flow when the voltage command effective value is the voltage command threshold Ea is set as the current detection threshold Ia. For example, in this example, the voltage command threshold Ea is determined based on the rated current Ir, and when there is no abnormality in the current detectors 7 and 8, if the voltage command effective value becomes the voltage command threshold Ea, the detected current value should be equivalent to the rated current Ir. Therefore, in this example, the current detection threshold Ia is set to a value lower than the rated current Ir, more specifically, a value obtained by multiplying the rated current Ir by an appropriate multiplier A that is equal to or greater than 0 and less than 1, as shown in equation (2). The multiplier A may be a value that takes into account errors in the circuit, calculation errors, and margins, but in this example, it is assumed that the value of the current detection value becomes almost 0 when the current detectors 7 and 8 fail, and for example, 0.5% of the rated current Ir (i.e., a value where A=0.005) is set as the current detection threshold Ia. Ia = Ir × A (0≦A<1) (2)

[0028] As described above, in this example, the actual voltage value when the reference current Idef flows is calculated taking into account the dead-time voltage error Edt, and this actual voltage value is set as the voltage command threshold Ea. A value smaller than the reference current Idef is set as the current detection threshold Ia. In this case, if the effective voltage value is equal to or greater than the voltage command threshold Ea but the detected current value is smaller than the current detection threshold Ia, it can be determined that some abnormality has occurred in the current detectors 7 and 8. Furthermore, because the voltage command threshold Ea is a value that reflects the dead-time voltage error Edt, erroneous detection and missed detection can be effectively prevented.

[0029] Next, another example of an abnormality detection technique for the current detectors 7 and 8 will be described with reference to FIG. 3. The motor control device 100 in FIG. 3 is obtained by adding dead time compensation to the motor control device 100 in FIG. 1, and the same components are given the same reference numerals and the description thereof will be omitted. In the example in FIG. 1, the voltage command values ​​Eu*, Ev*, and Ew* in a fixed coordinate system expressed by U, V, and W are output from the current control unit 1, but it is possible to perform dq conversion inside the current control unit 1. The current control unit 1 in FIG. 3 includes a command value calculation unit 12 and a dead time compensator 11, and the command value calculation unit 12 includes a dq axis current command value calculation unit 13, a dq axis voltage command value calculation unit 14, three-phase converters 15 and 16, and a dq converter 17.

[0030] The dq-axis current command value calculation unit 13 calculates a d-axis current command value and a q-axis current command value in a dq rotating coordinate system from a torque command value output by a higher-level control device (not shown). The dq converter 17 converts the U-phase current detection value Iu and the V-phase current detection value Iv in the fixed coordinate system into d-axis current detection value and q-axis current detection value in the dq rotating coordinate system. The dq-axis voltage command value calculation unit 14 calculates a d-axis voltage command value before dead-time compensation from the d-axis current command value and the d-axis current detection value, and calculates a q-axis voltage command value before dead-time compensation from the q-axis current command value and the q-axis current detection value. The three-phase converter 15 converts the d-axis voltage command value before dead-time compensation and the q-axis voltage command value before dead-time compensation in the dq rotating coordinate system into voltage command values ​​Eu*', Ev*', Ew*' in the fixed coordinate system by inverse dq conversion. In addition, the three-phase converter 16 converts the d-axis current command value and the q-axis current command value in the dq rotating coordinate system output by the dq-axis current command value calculation unit 13 into current command values ​​Iu*, Iv*, Iw* in a fixed coordinate system by performing an inverse dq transformation.

[0031] The deadtime compensator 11 includes a deadtime compensation value calculator 18, which adds a U-phase deadtime compensation value Eudt calculated by the deadtime compensation value calculator 18 to a U-phase voltage command value Eu*' before deadtime compensation, adds a V-phase deadtime compensation value Evdt calculated by the deadtime compensation value calculator 18 to a V-phase voltage command value Ev*' before deadtime compensation, and adds a W-phase deadtime compensation value Ewdt calculated by the deadtime compensation value calculator 18 to a W-phase voltage command value Ew*' before deadtime compensation. The deadtime compensation value calculator 18 calculates the U-phase deadtime compensation value Eudt, the V-phase deadtime compensation value Evdt, and the W-phase deadtime compensation value Ewdt, respectively, but only the U-phase will be explained below.

[0032] The dead-time compensation value calculator 18 has a dead-time compensation voltage parameter Edtp and a dead-time compensation current parameter Idt for each motor. The dead-time compensation current parameter Idt is the current value at which the dead-time voltage error Edt begins to stabilize, and the dead-time compensation voltage parameter Edtp is the dead-time voltage error Edt after stabilization. That is, as shown in FIG. 2, the dead-time voltage error Edt increases with an increase in voltage when the current is less than a predetermined current value Idt, i.e., the dead-time compensation current parameter Idt. On the other hand, when the current becomes equal to or greater than the dead-time compensation current parameter Idt, the dead-time voltage error stabilizes at the dead-time compensation voltage parameter Edtp, which is a predetermined value.

[0033] If the U-phase current command value Iu* exceeds the dead-time compensation current parameter Idt, the dead-time compensation voltage parameter Edtp is output as the U-phase dead-time compensation voltage parameter Eudt as shown in equation (3). If the U-phase current command value Iu* is equal to or less than the dead-time compensation current parameter Idt, the dead-time compensation voltage parameter Edtp multiplied by the ratio of the U-phase current command value Iu* to the dead-time compensation current parameter Idt is output as the U-phase dead-time compensation value Eudt as shown in equation (4). Eudt = Edtp (Iu * > Idt) (3) Eudt=Edtp×(Iu* / Idt) (Iu*≦Idt) ···(4)

[0034] Here, since the rated current Ir (and therefore the reference current Idef) is equal to or greater than the dead-time current parameter Idt, if the dead-time compensation voltage parameter Edtp is used as the dead-time voltage error Edt in the U-phase abnormality determiner 9 and the V-phase abnormality determiner 10 inside the abnormality determination unit 4, abnormality determination can be easily performed without having extra parameters. However, the dead-time compensation voltage parameter Edtp is a parameter tuned for each motor, and some error exists.

[0035] Next, another example of the current detector anomaly detection technique will be described with reference to Fig. 4. Fig. 4 is a diagram showing the configuration of a U-phase anomaly determiner 9. The U-phase anomaly determiner 9 includes a U-phase voltage command effective value calculator 22, a voltage command threshold value calculator 23, a U-phase current detection effective value calculator 24, a current detection threshold value calculator 25, and a U-phase anomaly signal output unit 26. The U-phase voltage command effective value calculator 22 determines the U-phase voltage command effective value from the U-phase voltage command value Eu*, and the U-phase current detection effective value calculator 24 determines the U-phase current detection effective value from the U-phase current detection value Iu.

[0036] In addition to the dead time Td, the carrier frequency Fca, and the power supply voltage value Ep, the voltage command threshold calculator 23 also receives a dead time compensation voltage parameter Edtp. As described above, the dead time compensation voltage parameter Edtp is a value set for each motor, and is the value of the dead time voltage error after stabilization. The voltage command threshold calculator 23 calculates the dead time voltage error calculation value Edtc based on the formula (5). That is, the dead time voltage error calculation value Edtc is a value obtained by multiplying the dead time Td by the carrier frequency Fca and the power supply voltage value Ep. In addition, the voltage command threshold calculator 23 switches the switch 29 so that the larger of the dead time voltage error calculation value Edtc or the dead time compensation voltage parameter Edtp set for each motor is output as the dead time voltage error Edt. Edtc = Td × Fca × Ep (5) Edt = max(Edtp,Edtc) (6)

[0037] The voltage command threshold calculator 23 calculates the voltage command threshold Ea expressed by the formula (1) by adding the dead time voltage error Edt to the ideal voltage command threshold Eir. For example, if an ideal voltage value at a rated current, calculated from a rated current Ir that can be continuously applied and a motor resistance value, is used as the ideal voltage command threshold Eir, an abnormality can be detected promptly before a current of more than the rated current Ir flows. As the current detection threshold Ia, a value obtained by multiplying the rated current Ir by an appropriate multiplier A between 0 and 1, as shown in formula (2), is used. The multiplier A may be set to the rated current Ir taking into account errors in the circuit, calculation errors, and margins, but for simplicity, the current detection threshold Ia may be set to, for example, 0.5% of the rated current Ir, assuming that a value close to 0 is output when the current detector breaks down.

[0038] When the U-phase voltage command effective value is equal to or greater than the voltage command threshold Ea and the U-phase current detection effective value is equal to or less than the current detection threshold Ia, the U-phase abnormality signal output unit 26 determines that there is an abnormality in the current detector 7, and outputs a U-phase current detector abnormality signal to a higher-level control device (not shown). The V-phase abnormality determiner 10 performs the same process as the U-phase abnormality determiner 9. However, since the voltage command threshold Ea and the current detection threshold Ia are the same values, they may be used interchangeably.

[0039] Next, with reference to FIG. 5, another example of an abnormality detection technique for the current detectors 7 and 8 will be described. The motor control device in FIG. 5 is different from the motor control device in FIG. 3 only in the internal configuration of the current control unit 1, and the other configurations are the same as those of the motor control device in FIG. 3. Therefore, in the motor control device in FIG. 5, the same configurations as those of the motor control device in FIG. 3 are assigned the same reference numerals, and their description will be omitted. In the motor control device in FIG. 5, the current control unit 1 performs three-phase feedback control. The current control unit 1 includes a three-phase current command value calculation unit 34 and a three-phase voltage command value calculation unit 35 in the command value calculation unit 12. The three-phase current command value calculation unit 34 receives a torque command value output by a higher-level control device (not shown) as an input, and outputs a current command value for each of the three phases. The three-phase voltage command value calculation unit 35 receives a current command value for each of the three phases and a current detection value for each of the U phase and the V phase as an input, and outputs voltage command values ​​Eu*', Ev*', and Ew*' before dead time compensation. However, the configuration described here is just an example, and the internal configuration of the current control unit 1 may be changed as long as the voltage command value in a fixed coordinate system is output from the current control unit 1.

[0040] The above description is merely an example, and other configurations may be changed as appropriate as long as a value reflecting the dead-time voltage error Edt is used as the voltage command threshold value Ea. For example, in the example of FIG. 4, the larger of the dead-time voltage error calculation value Edtc or the dead-time compensation voltage parameter Edtp is used as the dead-time voltage error Edt to ensure a margin and prevent erroneous detection. However, the smaller of the dead-time voltage error calculation value Edtc or the dead-time compensation voltage parameter Edtp may be selected to set a stricter threshold value to prevent missed detection. That is, the dead-time voltage error Edt may be specified based on equation (7). Edt = min(Edtp,Edtc) (7)

[0041] Even when dead-time voltage compensation is not performed, a separate dead-time voltage error parameter or the like may be provided instead of the dead-time compensation voltage parameter and used to specify the dead-time voltage error Edt.

[0042] In the above description, the current detectors are installed in the U and V phases, but the phases in which the current detectors are installed may be changed as appropriate. Therefore, in order to detect an abnormality in the current detector of each phase, the current detector may be installed in all three phases, or in only one of the phases.

[0043] In any case, the technology disclosed in this specification makes it possible to easily detect abnormalities in a current detector based on current-voltage characteristics that take into account dead-time voltage error, thereby preventing erroneous detection due to dead-time voltage error and currents greater than the rated current flowing in the event of an abnormality. [Explanation of symbols]

[0044] 1 current control unit, 2 PWM control unit, 3 motor, 4 abnormality determination unit, 5 converter, 6 three-phase AC power supply, 7, 8 current detector, 9 U-phase abnormality determination unit, 10 V-phase abnormality determination unit, 11 dead time compensator, 12 command value calculation unit, 13 dq-axis current command value calculation unit, 14 dq-axis voltage command value calculation unit, 15, 16 three-phase converter, 17 dq converter, 18 dead time compensation value calculator, 19, 20, 21 adder, 22 U-phase voltage command effective value calculator, 23 voltage command threshold calculator, 24 U-phase current detection effective value calculator, 25 current detection threshold calculator, 26 U-phase abnormality signal output unit, 27, 28, 33 multiplier, 29 switch, 30 adder, 31, 32 parameters, 34 three-phase current command value calculation unit, 35 three-phase voltage command value calculation unit, 100 motor control device.

Claims

1. A motor control device that controls driving of a three-phase motor, a current control unit that outputs a voltage command value for each of the three phases; a PWM control unit that converts a DC voltage output from a converter into an AC voltage by modulating a switching pulse width in response to the voltage command value, and applies the AC voltage to each of three power lines of the three-phase motor; one or more current detectors provided in at least one of the three-phase power lines, the current detectors detecting a value of a current flowing through the power line as a current detection value; an abnormality determination unit that determines whether or not the current detector is abnormal; The abnormality determination unit includes: calculating a voltage command threshold value by adding a dead-time voltage error, which is a voltage error caused by a dead time of the switching, to an ideal voltage command threshold value, which is a value obtained by multiplying a specified reference current value and a motor resistance value; outputting a signal indicating an abnormality in the current detector when the effective value of the voltage command value is equal to or greater than the voltage command threshold value and the effective value of the current detection value is equal to or less than a current detection threshold value that is a value lower than the reference current value; A motor control device comprising:

2. 2. The motor control device according to claim 1, The motor control device, wherein the abnormality determination unit calculates, as the dead-time voltage error, a value obtained by multiplying the dead time by a carrier frequency and a power supply voltage value of the DC voltage.

3. 2. The motor control device according to claim 1, the current control unit has a dead-time compensator that outputs, as the voltage command value for each of the three phases, a value obtained by adding a dead-time compensation value to a pre-compensation voltage command value for each of the three phases calculated based on a torque command value, and The dead time compensator comprises: If the current command value exceeds a specified dead-time compensation current parameter, a specified dead-time compensation voltage parameter is calculated as the dead-time compensation value; When the current command value is equal to or less than the dead-time compensation current parameter, a value obtained by multiplying the dead-time compensation voltage parameter by a ratio of the current command value to the dead-time compensation current parameter is calculated as the dead-time compensation value. A motor control device comprising:

4. 4. The motor control device according to claim 3, The motor control device, wherein the abnormality determination unit calculates, as the dead-time voltage error, a value obtained by multiplying the dead time by a carrier frequency and a power supply voltage value of the DC voltage.

5. 4. The motor control device according to claim 3, The motor control device, wherein the abnormality determination unit calculates the dead-time compensation voltage parameter as the dead-time voltage error.

6. 4. The motor control device according to claim 3, The abnormality determination unit is A value obtained by multiplying the dead time by a carrier frequency and a power supply voltage value of the DC voltage is calculated as a dead time voltage error calculation value; the dead-time compensation voltage parameter or the dead-time voltage error calculation value, whichever is larger, is calculated as the dead-time voltage error; A motor control device comprising:

7. 4. The motor control device according to claim 3, The abnormality determination unit is A value obtained by multiplying the dead time by a carrier frequency and a power supply voltage value of the DC voltage is calculated as a dead time voltage error calculation value; the dead-time compensation voltage parameter or the dead-time voltage error calculation value, whichever is smaller, is calculated as the dead-time voltage error; A motor control device comprising:

8. A method for detecting an abnormality in a current detector provided in a motor control device, comprising: calculating a voltage command threshold value by adding a dead-time voltage error, which is a voltage error caused by a dead time of switching for applying a voltage to the motor, to an ideal voltage command threshold value, which is a value obtained by multiplying a specified reference current value and a resistance value of the motor; outputting a signal indicating an abnormality in the current detector when the effective value of the voltage command value of the motor is equal to or greater than the voltage command threshold value and the effective value of the current detection value detected by the current detector is equal to or less than a current detection threshold value that is lower than the reference current value; 4. An anomaly detection method comprising:

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