JP6936759B2 - Diagnostic equipment, drive systems, diagnostic methods and programs - Google Patents

Description

The present invention relates to diagnostic devices, drive systems, diagnostic methods and programs.

As a method for detecting an abnormality in an induction motor (three-phase motor) or a rotating device connected to the induction motor, an abnormality detection technique using current data or voltage data of the induction motor is known. For example, Patent Document 1 discloses a technique for detecting a winding abnormality of an induction motor using current data and voltage data.

Japanese Patent No. 5875734

In an induction motor, for example, there are a plurality of types of abnormal states such as phase loss, ground fault, and layer short with respect to the winding of the stator. When an abnormality occurs in an induction motor, there is a need to not only simply diagnose normality / abnormality, but also to determine the abnormal condition that has occurred and evaluate the severity of the abnormality.

In addition, it is possible to determine the abnormal state and grasp its severity by adding new sensors, etc. inside and outside the induction motor, but it is troublesome to add such sensors, etc. And costly.

An object of the present invention is to provide a diagnostic device, a drive system, a diagnostic method and a program capable of more easily discriminating an abnormal state of a three-phase motor and evaluating its severity.

According to the first aspect of the present invention, the diagnostic device is a diagnostic device that detects an abnormality in a three-phase motor, and includes a motor current acquisition unit that acquires a measured value of the motor current of each phase and a motor current acquisition unit of each of the phases. Based on the measured value of the motor current, at least the abnormality detection unit that detects the occurrence of phase loss, the occurrence of ground fault, and the occurrence of layer short for the three-phase motor, and the occurrence of the phase loss are detected. If this is the case, the degree of the phase loss is estimated, if the occurrence of the ground fault is detected, the degree of the ground fault is estimated, and if the occurrence of the layer short is detected, the layer short is detected. It is provided with an abnormality degree estimation unit for estimating the degree of.

Further, according to the second aspect of the present invention, when the occurrence of the open phase is detected, the abnormal degree estimation unit determines the degree of the open phase with respect to one winding of the three-phase motor. Estimate the magnitude of the series resistance component.

Further, according to the third aspect of the present invention, when the occurrence of the ground fault is detected, the abnormality degree estimation unit determines the degree of the ground fault with respect to one winding of the three-phase motor. Estimate the magnitude of the resistance component of the ground fault path.

Further, according to the fourth aspect of the present invention, when the occurrence of the layer short is detected, the abnormality degree estimation unit is set to one winding of the three-phase motor as the degree of the layer short. Estimate the rate of layer shorts that occur.

Further, according to a fifth aspect of the present invention, the drive system includes the above-mentioned diagnostic device, the three-phase motor, and a power source for supplying three-phase AC power to the three-phase motor.

Further, according to the sixth aspect of the present invention, the diagnostic method is a method of detecting an abnormality of a three-phase motor, in which a step of acquiring a measured value of a motor current of each phase and a motor current of each phase are described. Based on the measured values of, at least the step of detecting the occurrence of phase loss, the occurrence of ground fault, and the occurrence of layer short for the three-phase motor, and when the occurrence of the phase loss is detected. Estimates the degree of the phase loss, estimates the degree of the ground fault when the occurrence of the ground fault is detected, and estimates the degree of the layer short when the occurrence of the layer short is detected. With steps to do.

Further, according to the seventh aspect of the present invention, the program includes a step of acquiring a measured value of the motor current of each phase in a computer of a diagnostic device capable of detecting an abnormality of the three-phase motor, and a motor of each phase. Based on the measured value of the current, at least the step of detecting the occurrence of phase loss, the occurrence of ground fault, and the occurrence of layer short for the three-phase motor, and the case where the occurrence of the phase loss is detected. The degree of the phase loss is estimated, the degree of the ground fault is estimated when the occurrence of the ground fault is detected, and the degree of the layer short is estimated when the occurrence of the layer short is detected. Perform the estimation step and.

According to each aspect of the above-described invention, it is possible to more easily determine the abnormal state of the three-phase motor and evaluate its severity.

It is a figure which shows the whole structure of the diagnostic apparatus and the like which concerns on 1st Embodiment. It is a figure which shows the functional structure of the diagnostic apparatus which concerns on 1st Embodiment. It is a 1st figure which shows the processing flow of the CPU which concerns on 1st Embodiment. It is a 2nd figure which shows the processing flow of the CPU which concerns on 1st Embodiment. FIG. 1 is a diagram for explaining a diagnostic process by a CPU according to the first embodiment. It is a 2nd figure for demonstrating the diagnostic process by a CPU which concerns on 1st Embodiment. It is a 3rd figure which shows the processing flow of the CPU which concerns on 1st Embodiment. It is a 3rd figure for demonstrating the diagnostic process by a CPU which concerns on 1st Embodiment. FIG. 4 is a diagram for explaining a diagnostic process by a CPU according to the first embodiment. It is a 4th figure which shows the processing flow of the CPU which concerns on 1st Embodiment. FIG. 5 is a diagram for explaining a diagnostic process by a CPU according to the first embodiment.

<First Embodiment>
Hereinafter, the three-phase motor diagnostic device according to the first embodiment and the drive system 9 including the diagnostic device will be described with reference to FIGS. 1 to 11.

(overall structure)
FIG. 1 is a diagram showing an overall configuration of a diagnostic device and the like according to the first embodiment.
As shown in FIG. 1, the drive system 9 includes a power supply P, a three-phase motor MT (three-phase induction motor), and a diagnostic device 1.
The diagnostic device 1 detects an abnormality in the three-phase motor MT driven based on the three-phase AC power supplied from the power supply P. The drive system 9 is applied to, for example, a power plant, a chemical plant, a waste treatment facility, and the like. For example, in a power plant, the power source P is a generator, and the three-phase motor MT is an induction motor that drives auxiliary machines (cooling fans, pumps, etc.) arranged in the power plant.

As shown in FIG. 1, the diagnostic apparatus 1 acquires the measured values of the U-phase, V-phase, and W-phase motor currents flowing from the power supply P to the three-phase motor MT, for example, via a clamp-type current sensor C. It is possible.

(Functional configuration of diagnostic device)
FIG. 2 is a diagram showing a functional configuration of the diagnostic apparatus according to the first embodiment.
As shown in FIG. 2, the diagnostic device 1 includes a CPU 10, a display unit 11, an operation unit 12, a memory 13, and a storage 14.

The CPU 10 is a processor that exerts various functions by operating according to a program prepared in advance and controls the entire operation of the diagnostic device 1.
The display unit 11 is an output device such as a liquid crystal display monitor, and outputs information to the observer of the drive system 9.
The operation unit 12 is an input device such as a mouse, a keyboard, and a touch sensor, and receives an operation of a monitor of the drive system 9.
The memory 13 is a so-called main storage device, and is a storage area for the CPU 10 to perform an operation according to a program.
The storage 14 is an auxiliary storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

By operating according to the program, the CPU 10 exerts functions as a motor current acquisition unit 100, an abnormality detection unit 101, and an abnormality degree estimation unit 102.

The motor current acquisition unit 100 acquires the measured value of the motor current of each phase via the current sensor C (FIG. 1).
The abnormality detection unit 101 detects the occurrence of "open phase", "ground fault", and "layer short" for the three-phase motor MT based on the measured values of the motor currents of each phase. do. "Open phase", "ground fault" and "layer short" are abnormal states that occur particularly on the stator side of the three-phase motor MT, respectively. Here, "open phase" refers to an abnormal state in which one of the transmission lines transmitting each phase (U phase, V phase, W phase) of three-phase AC power is disconnected or is in a state close to disconnection. Point to. A "ground fault" is an abnormality in which any transmission line that transmits each phase of three-phase AC power (U phase, V phase, W phase) is short-circuited with the grounding point or is in a state close to a short circuit. Refers to the state. Further, the “layer short” refers to an abnormal state in which at least a part of the windings arranged in the stator of the three-phase motor MT is short-circuited.
When the abnormality detection unit 101 detects the occurrence of "open phase", the abnormality degree estimation unit 102 estimates the degree of the phase loss. Further, the abnormality degree estimation unit 102 estimates the degree of the ground fault when the occurrence of the “ground fault” is detected by the abnormality detection unit 101. Further, the abnormality degree estimation unit 102 estimates the degree of the layer short when the occurrence of the “layer short” is detected.

(CPU processing flow)
FIG. 3 is a diagram showing a processing flow of the CPU according to the first embodiment.
The processing flow shown in FIG. 3 is repeatedly executed during the operation of the drive system 9.
First, the motor current acquisition unit 100 of the CPU 10 measures the motor currents of each of the three phases (U-phase motor current i _u , V-phase motor current i _v, and W-phase motor current i _{w) via the current sensor C.} (Step S00). The motor current acquisition unit 100 acquires the motor current in a sampling cycle of, for example, several milliseconds, and sequentially stores the motor current in the memory 13 or the like.

Next, the abnormality detection unit 101 and the abnormality degree estimation unit 102 of the CPU 10 refer to the measured values of the motor current acquired in step S00, and perform diagnostic processing for phase loss (step S10) and diagnostic processing for ground faults. (Step S20) and the diagnostic process (step S30) for the layer short are performed.
Hereinafter, each diagnostic process will be described in detail.

(Diagnostic processing for open phase)
FIG. 4 is a second diagram showing a processing flow of the CPU according to the first embodiment.
5 and 6 are FIGS. 1 and 2, respectively, for explaining the diagnostic processing by the CPU according to the first embodiment.
Hereinafter, the diagnostic process for phase loss (step S10 in FIG. 3) will be described in detail with reference to FIGS. 4 to 6.

As shown in FIG. 4, the abnormality detection unit 101 of the CPU 10 refers to the measured value of the motor current of each phase acquired in step S00 (FIG. 3), and determines whether or not a phase loss has occurred ( Step S11). Specifically, the abnormality detection unit 101, U-phase effective value _{i Urms} of the motor current, the effective value _{i vrms} the V-phase motor current, either predefined decision threshold rms _{i WRMS} the W-phase motor current It is determined whether or not it is _{th or less.} If the effective value _{i Urms} the U-phase motor current is less than or equal to the determination threshold _{i th} (step S11: NO), the abnormality detecting section 101 determines that the phase loss has occurred in the U phase. Further, when the effective value _{i vrms} the V-phase motor current is less than or equal to the determination threshold _{i th} (step S11: NO), the abnormality detecting section 101 determines that the phase loss has occurred in the V phase. Further, when the effective value _{i WRMS} the W-phase motor current is less than or equal to the determination threshold _{i th} (step S11: NO), the abnormality detecting section 101 determines that the phase loss has occurred in the W phase.
The determination threshold i _th, compared motor current estimated from the magnitude of the load of the three-phase motor MT, advance is defined as a value having a large significant difference than the measurement error.

On the other hand, if the effective value _{i Urms} the U-phase motor current, the effective value _{i vrms} the V-phase motor current, any of the effective value _{i WRMS} the W-phase motor current was above the determination threshold _{i th} (step S11: YES) , The abnormality detection unit 101 determines that no phase loss has occurred. In this case, the abnormality detection unit 101 outputs the notation "no phase loss" to the observer via the display unit 11 or the like (step S12).

Next, when the abnormality detection unit 101 detects the occurrence of a phase loss, the processing performed by the abnormality degree estimation unit 102 of the CPU 10 will be described in detail.

When the occurrence of a phase loss is detected (step S11: NO), the abnormality degree estimation unit 102 estimates _{the magnitude of the series resistance component R m} of the phase determined to have “phase loss” (step S13). Specifically, the anomaly degree estimation unit 102 uses the circuit model MD1 showing the occurrence of phase loss in an equivalent circuit and the equation (1) which is a voltage equation showing the electrical characteristics of the three-phase motor MT. The estimated value of the series resistance component R _{m is calculated.}

Here, the circuit model MD1 shown in FIG. 5 is, for example, an equivalent circuit showing that an open phase has occurred in the U phase of the three phases. Circuit model MD1 is, the three-phase motor U-phase winding _L U which is disposed in the primary (stator) of the MT, and the winding _{L W} of the winding of the V-phase _{L V} and W phase, the U-phase winding comprising a series resistance component _{R m} for the line _{L U.} The circuit model MD1 expresses the degree of phase loss by the magnitude of the _{series resistance component R m.} Note that "Va", "Vb", and "Vc" shown in FIG. 5 are applied to each of the U-phase winding L _U , the V-phase winding _LV , and the W-phase winding L _W , respectively. It is a voltage value.

Further, the equation (1) is an equation showing the relationship between the voltage applied to each phase of the three-phase motor MT and the current flowing through each phase of the three-phase motor MT, and is the motor constant of the three-phase motor MT. It is a voltage equation including. Each motor constant is derived from, for example, the relationship between voltage and current shown in a test report or the like provided by the manufacturer. In the formula (1), "Va", "Vb", and "Vc" are voltage values applied to the U-phase, V-phase, and W-phase windings arranged on the primary side (stator), respectively. Yes (see Figure 5). Further, "L1" and "L2" are the primary side leakage inductance and the secondary side leakage inductance, respectively. Further, "M" is 3/2 · Lm, and "Lm" is the exciting inductance. Further, "R1" and "R2" are primary resistors and secondary resistors, respectively. Further, "θa" is "ωt" (product of angular frequency ω and time t), and "θb" and "θc" are "θa + 2 / 3π" and "θa + 4 / 3π", respectively. Further, "Isa", "Isb", and "Isc" are currents of each phase (U phase, V phase, W phase) flowing to the primary side (stator), and are "Ira", "Irb", and "Irb". "Irc" is the current flowing to the secondary side (rotor) corresponding to the current of each phase on the primary side.

An AC voltage having a known amplitude and frequency is applied from the power supply P to each of the U-phase, V-phase, and W-phase input terminals of the circuit model MD1. In this case, as shown in FIG. 5, the voltage value Va applied to the winding L _U of the three-phase motor MT is determined by the magnitude of the series resistance component R _m are serially connected to the winding L _U NS. And the voltage value Va applied via a series resistance component R _m from a power source P, (not through the series resistance component) normally from the power source P voltage Vb applied, and the Vc is applied to the three-phase motor MT In this case, the effective value i _urms of the U-phase motor current can be obtained by substituting the voltage values Va, Vb, and Vc into the equation (1). As a result, as shown in FIG. 6, a function F1 showing the relationship between _{the effective value irms} of the U-phase motor current and the series resistance component R _{m is obtained.}
Abnormality degree estimation unit 102 estimates the magnitude of the series resistance component R _m by applying the effective value i _Urms of measured equal to or less than the determination threshold i _th U-phase motor current in function F1.

Returning to FIG. 4, the abnormality degree estimation unit 102 subsequently _{determines whether or not the series resistance component R m} estimated in step S13 is within the permissible range (step S14). In step S14, the abnormality degree estimation unit 102 determines whether or not the degree of phase loss is within the permissible range based on the magnitude _{of the series resistance component R m.} That is, the abnormality degree estimation unit 102 _{compares the series resistance component R m} estimated in step S13 with the pre-defined phase _loss tolerance determination threshold value R to 1. When the series resistance component R _{m is equal to or less than the phase loss} tolerance determination threshold value R to 1, the abnormality degree estimation unit 102 determines that the series resistance component R _m is within the allowable range (step S14: YES). In this case, the abnormality degree estimation unit 102 outputs the notation “with phase loss (within allowable range)” and the rate of increase in resistance R _m / R ₀ due to the occurrence of phase loss to the observer ( Step S15). Here, "R ₀ " is a resistance value in a normal state.
On the other hand, when the series resistance component R _{m exceeds the phase loss} tolerance determination threshold value R to 1, the abnormality degree estimation unit 102 determines that the series resistance component R _m is out of the allowable range (step S14: NO). In this case, the abnormality degree estimation unit 102 outputs the notation “with phase loss (outside the allowable range)” and the rate of increase in resistance R _m / R ₀ due to the occurrence of phase loss to the observer ( Step S16).

(Diagnostic processing for ground faults)
FIG. 7 is a third diagram showing a processing flow of the CPU according to the first embodiment.
8 and 9 are FIGS. 3 and 4, respectively, for explaining the diagnostic processing by the CPU according to the first embodiment.
Hereinafter, the diagnostic process for the ground fault (step S20 in FIG. 3) will be described in detail with reference to FIGS. 7 to 9.

As shown in FIG. 7, the abnormality detection unit 101 of the CPU 10 refers to the measured value of the motor current of each phase acquired in step S00 (FIG. 3) and determines whether or not a ground fault has occurred ( Step S21). Specifically, the abnormality detection section 101, peak value _{i 0p} of the zero-phase current _{i 0 (= i u + i} v + i w) determines whether is below the predetermined determination threshold value _{i th0.} If the peak value _{i 0p} of the zero-phase current was determined threshold value _{i th0} or more (step S21: NO), the abnormality detecting section 101 determines that a ground fault has occurred.

On the other hand, if the peak value _{i 0p} of zero-phase current is less than the determination threshold value _{i th0} (step S21: YES), the abnormality detecting section 101 determines that a ground fault has not occurred. In this case, the abnormality detection unit 101 outputs the notation "no ground fault" to the observer via the display unit 11 or the like (step S22).

Next, when the abnormality detection unit 101 detects the occurrence of a ground fault, the processing performed by the abnormality degree estimation unit 102 of the CPU 10 will be described in detail.

When the occurrence of a ground fault is detected (step S21: NO), the abnormality degree estimation unit 102 _{Fourier transforms the zero-phase current i 0} to calculate the peak value P _fm of the power supply frequency component (step S23). Here, when the transmission lines of the U-phase, V-phase, and W-phase are all normally insulated, the zero-phase current i ₀ of the three-phase motor MT (U-phase motor current i _u , V-phase motor current i). the sum of _v and the W-phase motor current i _w) is always zero. However, if a ground fault occurs in any of the three phases, a current that flows to the grounding point is generated without passing through the three-phase motor MT, so that the zero-phase current i ₀ does not become zero and the power supply frequency. The AC component that oscillates in is included. Therefore, the abnormality degree estimation unit 102, a zero-phase current i ₀ by calculating the peak value P _fm power frequency components by Fourier transform, through land-circuiting, knowing how much current is flowing Can be done.

Subsequently, the anomaly degree estimation unit 102 determines the resistance component R _n (that is, between the transmission line and the ground point) of the ground _{fault path based on the calculated peak value P fm} of the power frequency component of _{the zero-phase current i 0.} Insulation resistance) is estimated (step S24). Specifically, the anomaly degree estimation unit 102 uses a circuit model MD2 showing the occurrence of a ground fault in an equivalent circuit and an equation (1) which is a voltage equation showing the electrical characteristics of the three-phase motor MT. The estimated value of the resistance component R _{n of the ground fault path is calculated.}

Here, the circuit model MD2 shown in FIG. 8 is, for example, an equivalent circuit showing that a ground fault has occurred in the U phase of the three phases. Circuit model MD2, the three-phase motor U-phase winding _L U which is disposed in the primary (stator) of the MT, and the winding _{L W} of the winding of the V-phase _{L V} and W phase, the U-phase winding made and a resistance component R _n of the earth-circuiting generated with respect to the line L _U. The circuit model MD2 expresses the degree of ground fault by the magnitude of the resistance component R _{n of this ground fault path.} Note that "Va", "Vb", and "Vc" shown in FIG. 8 are the U-phase winding L _U , the V-phase winding _LV , and the W-phase winding L _{W, respectively, as in FIG.} It is a voltage value applied to each.

An AC voltage having a known amplitude and frequency is applied from the power supply P to each of the U-phase, V-phase, and W-phase input terminals of the circuit model MD2. In this case, winding _L U of the three-phase motor _MT, L V, the voltage value Va to be applied to each of the _{L W,} Vb, Vc, as shown in FIG. 8, U-phase, V-phase from the power source P, It is the voltage value normally applied to each input terminal of the W phase. However, according to the circuit model MD2, the current flowing through the U-phase is composed a current flowing in the winding L _U of the three-phase motor MT, the sum of the current flowing in the resistance component R _n of the earth-circuiting. Here, the magnitude of the peak value P _fm (power frequency component of the zero-phase current i ₀ ) obtained in step S23 is proportional to the current value flowing through _{the resistance component R n of the ground fault path.} As a result, as shown in FIG. 9, from Ohm's law (V = IR), a function F2 showing the relationship (inverse proportional relationship) between _{the peak value P fm} and the resistance component R _{n of the ground fault path is obtained.}
The anomaly degree estimation unit 102 estimates the magnitude of the resistance component R _{n of the ground fault path by applying the peak value P fm calculated in step S23 to the function F2.}

Returning to FIG. 7, the abnormality degree estimation unit 102 subsequently _{determines whether or not the resistance component R n} of the ground fault path estimated in step S24 is within the permissible range (step S25). In step S25, the abnormality degree estimation unit 102 determines whether or not the degree of the ground fault is within the permissible range based on the magnitude _{of the resistance component R n of the ground fault path.} That is, the abnormality degree estimation unit 102 comparing the ground fault tolerance determination threshold value R _to2 defined in advance and the resistance component R _n of the earth-circuiting estimated in step S24. When the resistance component _{R n} of the earth-circuiting was at ground allowable determination threshold value _{R to2} more (step S25: YES), the abnormality degree estimation unit 102, the resistance component _{R n} of the earth-circuiting is within the acceptable range Judgment (step S25: YES). In this case, the abnormality degree estimation unit 102 outputs the notation “with ground fault (within allowable range)” and the resistance component R _n of the ground fault path to the observer (step S26).
On the other hand, if the resistance component R _n of the earth-circuiting was below ground allowable determination threshold value R _to2, abnormal about estimating unit 102 determines that the resistance component R _n of the earth-circuiting is outside the allowable range (step S25: NO). In this case, the abnormality degree estimation unit 102 outputs the notation “with ground fault (outside the allowable range)” and the resistance component R _n of the ground fault path to the observer (step S27).

(Diagnostic processing for layer shorts)
FIG. 10 is a fourth diagram showing a processing flow of the CPU according to the first embodiment.
FIG. 11 is a fifth diagram for explaining the diagnostic process by the CPU according to the first embodiment.
Hereinafter, the diagnostic process for the layer short (step S30 in FIG. 3) will be described in detail with reference to FIGS. 10 to 11.

As shown in FIG. 10, the abnormality detection unit 101 of the CPU 10 refers to the measured value of the motor current of each phase acquired in step S00 (FIG. 3), and determines whether or not a layer short has occurred ( Step S31). Specifically, the abnormality detection unit 101 first calculates _{the magnitude i dq} of the combined vector of _{the d-axis current id} and the q-axis current i _{q based on the equation (2).}

Here, when the inductance values of the U-phase winding L _U , the V-phase winding _LV, and the W-phase winding L _W are all equal, the three phases are in a balanced state, so that the d-axis current is present. resultant vector of i _d and the q-axis current i _q since draws circular trajectory on dq coordinate plane in synchronization with the power frequency, the magnitude i _dq is always constant. _{Therefore, when the magnitude i dq} of the combined vector of the d-axis current _id and the q-axis current i _q is Fourier transformed, only the peak of the DC component appears. However, when a layer short occurs in any one of the U-phase winding L _U , the V-phase winding _LV, and the W-phase winding L _W , the inductance value of the winding in which the layer short occurs increases. It decreases and becomes a three-phase imbalance. Then, the resultant vector of the d-axis current i _d and the q-axis current i _q is an elliptical orbit on dq coordinate plane in synchronization with the power frequency. _{Therefore, when the magnitude i dq} of the combined vector of _{the d-axis current id} and the q-axis current i _q is Fourier-transformed in the state where the layer short occurs, not only the peak of the DC component but also twice the power frequency is doubled. A peak occurs at the frequency. Hereinafter, a frequency twice the power supply frequency is also referred to as a “power supply frequency double component”.

The abnormality detection unit 101 _{calculates the peak value P 2fm} of the power frequency double component of _{the magnitude i dq} of the combined vector of _{the d-axis current id} and the q-axis current i _q, and determines that the peak value P _2fm is a predetermined value. It is determined whether or not the threshold value _{is below P th. When the peak value P 2fm} of the power frequency double component of the magnitude i _dq of the composite vector is equal to or greater than the determination threshold value P _th (step S31: NO), the abnormality detection unit 101 determines that a layer short has occurred.

On the other hand, when _{the peak value P 2fm} of the power frequency double component of _{the magnitude i dq} of the composite vector is lower than the determination threshold value P _th (step S31: YES), the abnormality detection unit 101 does not have a layer short circuit. Is determined. In this case, the abnormality detection unit 101 outputs the notation "no layer short" to the observer via the display unit 11 or the like (step S32).

Next, when the abnormality detection unit 101 detects the occurrence of a layer short, the processing performed by the abnormality degree estimation unit 102 of the CPU 10 will be described in detail.

When the occurrence of a layer short is detected (step S31: NO), the abnormality degree estimation unit 102 of the three-phase motor MT is based on _{the peak value P 2fm} of the power frequency double component of _{the magnitude idq of the composite vector.} The rate of layer shorts generated in the windings is estimated (step S33). Specifically, the abnormality degree estimation unit 102 is an equation (3) which is a voltage equation showing the electrical characteristics of the circuit model MD3 in which the occurrence of the layer short is shown by the equivalent circuit and the three-phase motor MT in which the layer short is generated. And, the ratio of layer shorts is calculated.

Here, the circuit model MD3 shown in FIG. 11, as an example, is an equivalent circuit indicating that the layer short-circuit occurs in the windings L _U of the three-phase U-phase. _{The circuit model MD3 has a U-phase winding L U} , a V-phase winding _LV, and a W-phase winding L _W arranged on the primary side (stator) of the three-phase motor MT. According to the circuit model MD3, winding L _U of the U-phase, contribute inductance component L _U1 to drive the three-phase motor MT not shorted, is separated into an inductance component L _U2 were shorted. In this case, the ratio of the layer short is the ratio of the short-circuited inductance component L _U 2 to the inductance (L _{U 1} + L _{U 2 ) of the entire U-phase winding L U.}

Equation (3) has the formula shown and voltage layer shorting the windings L _U of the U phase is applied to each phase of the three-phase motor MT generated, the relationship between the current flowing through each phase of the three-phase motor MT It is a voltage equation including the motor constant of the three-phase motor MT. However, "Isa" in the equation (3) is the _{current flowing through the inductance component L U1} of the circuit model MD3, and "Isd" is the current flowing through _{the inductance component L U2 of the circuit model MD3. Further, “k 11 to k 77} ” and “m _{11 to} m ₇₇ ” in the equation (3) are coefficients that are uniquely specified according to the ratio of the layer shorts that have occurred.
Abnormality degree estimation unit 102, the abnormality degree estimation unit 102, while changing the coefficients _{k 11 ~k 77, m 11 ~m} 77 of formula (3), obtained in step S00 U-phase motor current _i u, identifying a combination of V-phase motor current _{i v} each coefficient obtained by the same current waveform and the measured value of and W-phase motor current _{i w k 11 ~k 77, m} 11 ~m 77. Abnormality degree estimation unit 102 can estimate the proportion of the layer short-circuit occurs in the windings _{L U} of the U phase from the combination of the coefficient _{k 11 ~k 77, m 11 ~m} 77 identified.

Returning to FIG. 10, the abnormality degree estimation unit 102 subsequently determines whether or not the ratio of the layer shorts estimated in step S33 is within the permissible range (step S34). In step S34, the abnormality degree estimation unit 102 determines whether or not the degree of layer short is within the permissible range based on the ratio of layer shorts. That is, the abnormality degree estimation unit 102 compares the ratio of the layer shorts estimated in step S33 with the predetermined layer short tolerance determination threshold value. When the ratio of layer shorts is equal to or less than the layer short tolerance determination threshold value (step S34: YES), the abnormality degree estimation unit 102 determines that the ratio of layer shorts is within the allowable range (step S34: YES). In this case, the abnormality degree estimation unit 102 outputs the notation “There is a layer short (within the allowable range)” and the ratio of the layer shorts to the observer (step S35).
On the other hand, when the ratio of layer shorts exceeds the layer short tolerance determination threshold value, the abnormality degree estimation unit 102 determines that the ratio of layer shorts is out of the allowable range (step S34: NO). In this case, the abnormality degree estimation unit 102 outputs the notation “There is a layer short (outside the allowable range)” and the ratio of the layer shorts to the observer (step S36).

Incidentally, the formula (3) used in the above description, only a voltage applied to each phase of the three-phase motor MT Layer short circuit occurs in the windings L _U of the U-phase, each phase of the three-phase motor MT It is a voltage equation showing the relationship with the current flowing through.
And voltage layer shorting the winding L _V V-phase are applied to each phase of the three-phase motor MT generated, the voltage equation representing the relationship between the current flowing through each phase of the three-phase motor MT has the formula (3 ) Of the 7 × 7 matrix elements of one item on the right side, each matrix element “Mcosθa × k ₇₄ ”, “Mcosθb × k ₇₅ ”, and “Mcosθc × k ₇₆ ” in the 4th to 6th columns of the 7th row are selected. , "Mcosθc × k ₇₄ ", "Mcosθa × k ₇₅ ", "Mcosθb × k _{76 ", and each matrix element "Mcosθa × k 47} ", "Mcosθb × k ₅₇ " in the 7th column of the 4th to 6th rows. , And “Mcosθc × k ₆₇ ” are changed to “Mcosθc × k ₄₇ ”, “Mcosθa × k ₅₇ ”, and “Mcosθb × k ₆₇ ”, respectively.
Further, the voltage equation showing the relationship between the voltage applied to each phase of the three-phase motor MT in which the layer short is generated in the winding LW of the _{W phase and the current flowing in each phase of the three-phase motor MT is expressed by the equation.} (3) Of the 7 × 7 matrix elements of one item on the right side, each matrix element “Mcosθa × k ₇₄ ”, “Mcosθb × k ₇₅ ”, “Mcosθc × k ₇₆ ” in the 4th to 6th columns of the 7th row is selected. , "Mcosθb × k ₇₄ ", "Mcosθc × k ₇₅ ", and "Mcosθa × k ₇₆ ", respectively, and each matrix element "Mcosθa × k ₄₇ ", "Mcosθb ×" in the 7th column of the 4th to 6th rows. It can be obtained by changing "k ₅₇ " and "Mcos θc × k ₆₇ " to “Mcos θb × k ₄₇ ”, “Mcos θc × k ₅₇ ”, and “Mcos θa × k _{67”, respectively.}

(Action, effect)
As described above, the diagnostic apparatus 1 according to the first embodiment has at least the occurrence of phase loss, the occurrence of ground faults, and the occurrence of ground faults in the three-phase motor MT based on the measured values of the motor currents of the three-phase motors. Detect each occurrence of layer short. Then, the diagnostic apparatus 1 estimates the degree of the open phase when the occurrence of the phase loss is detected, estimates the degree of the ground fault when the occurrence of the ground fault is detected, and causes a layer short. When the occurrence is detected, the degree of the layer short is estimated.
By doing so, it is possible to determine the abnormal state that has occurred and evaluate the severity thereof. As a result, even if some abnormality is detected in the drive system 9, the equipment owner of the drive system 9 can flexibly continue the operation from the viewpoint of cost if the severity of the abnormality is relatively small. Can be taken. In addition, by using the results of a plurality of periodic inspections, the degree of progress of symptoms can be grasped, so that an appropriate maintenance plan can be made.

Further, since the diagnostic apparatus 1 according to the first embodiment performs the above-mentioned diagnosis based only on the measured values of the motor currents of the three-phase motors flowing between the power supply P and the three-phase motor MT, a new sensor is used. It can be easily realized without the need for additional equipment such as.

From the above, according to the diagnostic apparatus 1 according to the first embodiment, it is possible to more easily determine the abnormal state of the three-phase motor and evaluate its severity.

In each of the above-described embodiments, the various processing processes of the diagnostic device 1 described above are stored in a computer-readable recording medium in the form of a program, and the computer reads and executes the program to perform the above-mentioned. Various processes are performed. The computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Further, this computer program may be distributed to a computer via a communication line, and the computer receiving the distribution may execute the program.

The above program may be for realizing a part of the above-mentioned functions. Further, it may be a so-called difference file (difference program) that can realize the above-mentioned function in combination with a program already recorded in the computer system.

Further, in another embodiment, a part of each function of the diagnostic apparatus 1 described in each of the above-described embodiments may be provided by another computer connected by a network.

As described above, some embodiments according to the present invention have been described, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

1 Diagnostic device 10 CPU
100 Motor current acquisition unit 101 Abnormality detection unit 102 Abnormality degree estimation unit 11 Display unit 12 Operation unit 13 Memory 14 Storage P Power supply MT Three-phase motor C Current sensor

Claims (8)

A diagnostic device that detects abnormalities in three-phase motors.
A motor current acquisition unit that acquires the measured value of the motor current of each phase,
An abnormality detection unit that detects the occurrence of open phase for the three-phase motor based on the measured value of the motor current of each phase.
When the occurrence of the open phase is detected, the abnormal degree estimation unit that estimates the degree of the open phase, and the abnormal degree estimation unit.
With
When the occurrence of the open phase is detected, the abnormal degree estimation unit estimates the magnitude of the series resistance component with respect to one winding of the three-phase motor as the degree of the open phase.
Diagnostic device. A diagnostic device that detects abnormalities in three-phase motors.
A motor current acquisition unit that acquires the measured value of the motor current of each phase,
An abnormality detection unit that detects the occurrence of a layer short for the three-phase motor based on the measured value of the motor current of each phase.
And abnormality degree estimation unit for estimating the extent of the layer short circuit when the occurrence of the previous SL-layer short is detected,
With
When the occurrence of the layer short is detected, the abnormality degree estimation unit estimates the ratio of the layer short generated in one winding of the three-phase motor as the degree of the layer short.
Diagnostic device. The abnormality detection unit further detects the occurrence of a ground fault based on the measured value of the motor current of each of the phases.
When the occurrence of the ground fault is detected, the abnormality degree estimation unit estimates the magnitude of the resistance component of the ground fault path with respect to one winding of the three-phase motor as the degree of the ground fault.
The diagnostic device according to claim 1 or 2. The diagnostic device according to any one of claims 1 to 3,
With the three-phase motor
A power supply that supplies three-phase AC power to the three-phase motor,
Drive system with. It is a method to detect abnormalities in three-phase motors.
Steps to acquire the measured value of the motor current of each phase,
A step of detecting the occurrence of a phase loss in the three-phase motor based on the measured value of the motor current of each phase, and
When the occurrence of the open phase is detected, the step of estimating the degree of the open phase and
With
In the step of estimating the degree of phase loss, when the occurrence of the phase loss is detected, the magnitude of the series resistance component with respect to one winding of the three-phase motor is estimated as the degree of phase loss. ,
Diagnostic method. For computers with diagnostic equipment that can detect abnormalities in three-phase motors
Steps to acquire the measured value of the motor current of each phase,
A step of detecting the occurrence of a phase loss in the three-phase motor based on the measured value of the motor current of each phase, and
When the occurrence of the open phase is detected, the step of estimating the degree of the open phase and
To run,
In the step of estimating the degree of phase loss, when the occurrence of the phase loss is detected, the magnitude of the series resistance component with respect to one winding of the three-phase motor is estimated as the degree of phase loss. ,
program. It is a method to detect abnormalities in three-phase motors.
Steps to acquire the measured value of the motor current of each phase,
A step of detecting the occurrence of a layer short based on the measured value of the motor current of each phase, and
When the occurrence of the layer short is detected, the step of estimating the degree of the layer short and the step
With
In the step of estimating the degree of the layer short, when the occurrence of the layer short is detected, the ratio of the layer short generated in one winding of the three-phase motor is estimated as the degree of the layer short. ,
Diagnostic method. For computers with diagnostic equipment that can detect abnormalities in three-phase motors
Steps to acquire the measured value of the motor current of each phase,
A step of detecting the occurrence of a layer short based on the measured value of the motor current of each phase, and
When the occurrence of the layer short is detected, the step of estimating the degree of the layer short and the step
To run,
In the step of estimating the degree of the layer short, when the occurrence of the layer short is detected, the ratio of the layer short generated in one winding of the three-phase motor is estimated as the degree of the layer short. ,
program.

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