Eccentricity amount calculation device and method of rotary electric machine and control device of rotary electric machine

Abstract

To provide an eccentricity amount calculation device and method for a rotary electric machine, and a control device for a rotary electric machine, capable of calculating an eccentricity amount with high accuracy using voltage and current values obtained by a system that drives the rotary electric machine.SOLUTION: A processor 370 of an eccentricity amount calculation device 300 acquires a voltage command that is coordinate-transformed into a control dc-qc coordinate system for windings of respective phases of a rotary electric machine, or a multiphase voltage applied to the windings of the respective phases and coordinate-transformed into the control dc-qc coordinate system, and acquires a current command that is coordinate-transformed into the control dc-qc coordinate system for the windings of the respective phases, or a multiphase current flowing through the windings of the respective phases and coordinate-transformed into the control dc-qc coordinate system, and calculates an eccentricity amount of the rotary electric machine based on the acquired voltage command or voltage, the current command or current, constants of the rotary electric machine stored in advance in a memory 380, and an eccentricity amount calculation formula.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for calculating the eccentricity of a rotary electric machine and a control device for the rotary electric machine, and more particularly to a technique for determining the eccentricity from voltages and currents detected by a control device for the rotary electric machine. [Background technology]

[0002] Rotating electric machines can break down due to aging. In particular, the electric motors used to drive the spindles of servo press machines can experience excessive loads on their bearings due to vibrations from the press. In the worst case scenario, the bearings can break, causing the rotor and stator of the motor to come into contact. Therefore, a method is needed to detect this before the rotor and stator come into contact.

[0003] To detect contact between the rotor and the stator in advance, it is necessary to determine the amount of eccentricity of the rotor and / or stator of the motor.

[0004] Conventionally, methods disclosed in Patent Documents 1 to 3 have been proposed as examples of methods for determining the eccentricity of the rotor and / or stator of an electric motor.

[0005] Patent Document 1 discloses a method for estimating eccentricity of a rotating electric machine that includes a rotor and a stator with a plurality of windings arranged circumferentially, and that estimates the eccentricity of the rotating electric machine by measuring the terminal voltage or winding current of each winding when a voltage is applied to at least three or more windings of the stator.The rotating electric machine has three phases, U, V, and W, each with three windings connected in series, and the three windings of the U phase, for example, are positioned at 120° intervals from one another, and by measuring the terminal voltages of these three windings, the eccentricity state can be determined and the eccentricity rate can be estimated.

[0006] Furthermore, Patent Document 2 discloses a method in which the relationship between the voltage and the air gap length between the stator and rotor near a certain winding is determined in advance, and an arbitrary air gap length (relationship with the amount of axial misalignment) is calculated by measuring the voltage of two windings and applying the previously determined relational equation between the air gap length and voltage to the air gap length between the stator and rotor near each of the two windings, thereby calculating the amount of axial misalignment.

[0007] The inventions described in Patent Documents 1 and 2 are an excellent technical idea in which the windings that make up a certain phase of a motor are arranged in different spatial positions, and when the motor is eccentric, the terminal voltages of the windings become different values, and this is utilized to determine the eccentricity factor (amount of eccentricity).Patent Documents 1 and 2 disclose examples in which an AC voltage is applied to a motor or the motor is operated as a generator by external drive, and the relationship between the eccentricity factor (amount of eccentricity) and voltage is determined by obtaining the effective AC voltage value or a DC amount equivalent to the effective AC voltage value using special hardware, but they do not disclose or suggest a method for determining the relationship between the voltage command or voltage used in a vector control system and the amount of eccentricity to calculate the amount of eccentricity.

[0008] Furthermore, the inventions described in Patent Documents 1 and 2 are intended to measure the eccentricity of an electric motor during assembly, and do not disclose or suggest a device configuration that would allow the eccentricity of an aged, deteriorated electric motor to be easily measured at the customer's site after the sale. If the eccentricity of an electric motor were to be measured at the customer's site using the methods described in Patent Documents 1 and 2, one possible method would be to remove the electric motor installed in the customer's device and connect a separately provided eccentricity measurement unit and an externally driven electric motor to the removed electric motor for measurement, but it is not difficult to imagine that measuring the eccentricity would require a great deal of effort and cost.

[0009] As another example of a method for determining the eccentricity of an electric motor, Patent Document 3 discloses a rotating machine system having a rotating machine and a power conversion device connected to the rotating machine, the rotating machine system having a current measurement unit that measures phase currents, a current vector calculation unit that performs three-phase to two-phase conversion on the phase currents to calculate a current vector, an analysis target quantity calculation unit that calculates an analysis target quantity based on the current vector, a feature waveform extraction unit that extracts a waveform in a specific frequency range based on the analysis target quantity, and an abnormality degree calculation unit that calculates an abnormality degree based on the extracted waveform.

[0010] The invention of Patent Document 3 can detect abnormalities (eccentricity, etc.) in a rotating machine system having a rotating machine and a power conversion device connected to it, so it is thought that it is easier to perform measurements at the customer's site after the sale of the motor, which was difficult with the methods of Patent Documents 1 and 2 mentioned above, compared to the methods of Patent Documents 1 and 2.

[0011] However, although Patent Document 3 can detect eccentricity, it does not disclose a method for estimating the specific amount of eccentricity with high accuracy. If the specific amount of eccentricity cannot be estimated with high accuracy, the accuracy of abnormality determination will inevitably be low. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-229226 [Patent Document 2] Japanese Patent Application Publication No. 2018-74635 [Patent Document 3] Japanese Patent Publication No. 2020-114084 Summary of the Invention [Problem to be solved by the invention]

[0013] One embodiment of the technology disclosed herein provides an apparatus and method for calculating the eccentricity of a rotating electric machine, and a control device for a rotating electric machine, which can calculate the eccentricity with high accuracy using voltage and current values ​​acquired in a system that drives the rotating electric machine. [Means for solving the problem]

[0014] A first aspect of the present invention is an apparatus for calculating eccentricity of a rotary electric machine, comprising a processor and a memory that stores constants and eccentricity equations for a polyphase rotary electric machine, wherein the processor acquires voltage commands to windings of each phase of the rotary electric machine that have been coordinate-transformed into a DC-QC coordinate system for control, or voltages to which polyphase voltages applied to the windings of each phase have been coordinate-transformed into the DC-QC coordinate system for control, and current commands to the windings of each phase that have been coordinate-transformed into the DC-QC coordinate system for control, or currents to which polyphase currents flowing through the windings of each phase have been coordinate-transformed into the DC-QC coordinate system for control, and calculates the eccentricity of the rotary electric machine based on the acquired voltage commands or voltages, current commands or currents, and the constants and eccentricity equations for the rotary electric machine stored in the memory.

[0015] According to the first aspect of the present invention, a voltage command to be applied to the windings of each phase of a rotary electric machine and coordinate-transformed into the DC-QC coordinate for control, or a voltage obtained by coordinate-transforming the polyphase voltage applied to the windings of each phase into the DC-QC coordinate for control, and a current command to be applied to the windings of each phase and coordinate-transformed into the DC-QC coordinate for control, or a current obtained by coordinate-transforming the polyphase current flowing through the windings of each phase into the DC-QC coordinate for control, are acquired, and the eccentricity of the rotary electric machine is calculated based on the acquired voltage command or voltage, current command or current, and rotary electric machine constants and an eccentricity calculation formula stored in advance in a memory. This makes it possible to determine the eccentricity with high accuracy, and further to determine the eccentricity in a system that drives the rotary electric motor.

[0016] In a second aspect of the present invention, in the first aspect of the device for calculating eccentricity of a rotary electric machine, the formula preferably includes a first formula indicating a relationship between an air gap length between the rotor and the stator of the rotary electric machine and a voltage related to magnetic flux linkage in a specific winding when the rotor of the rotary electric machine is eccentric with respect to a representative circumferential position of the specific winding and when the rotary electric machine is operated under specific operating conditions, the air gap length being determined from a map of the air gap length and the voltage related to the magnetic flux linkage in the specific winding; and the processor preferably calculates the voltage related to the magnetic flux linkage from the acquired voltage command or the voltage and the acquired current command or the current for each winding when the rotary electric machine is operated under the same operating conditions as the specific operating conditions, determines the air gap length corresponding to each winding by substituting the calculated voltage related to magnetic flux linkage into the first formula, and calculates the eccentricity of the rotary electric machine from the determined air gap length.

[0017] According to a second aspect of the present invention, a first arithmetic expression representing the relationship between a voltage related to magnetic flux linkage and an air gap length is used as the arithmetic expression stored in the memory. This first arithmetic expression is an approximation expression obtained from a map of the air gap length between the rotor and the stator and the voltage related to magnetic flux linkage in a specific winding when the rotor of the rotary electric machine is eccentric with respect to a representative circumferential position of the specific winding and is operated under specific operating conditions. The representative circumferential position (angle) of the specific winding can be determined appropriately by the implementer. The processor calculates the voltage related to magnetic flux linkage from the acquired voltage command or voltage and current command or current for each winding when operated under the same operating conditions as the specific operating conditions, substitutes the calculated voltage into the first arithmetic expression to determine the air gap length corresponding to each winding, and calculates the eccentricity of the rotary electric machine from the determined air gap length.

[0018] A third aspect of the present invention provides an eccentricity calculation device for a rotary electric machine, wherein, in the second aspect, the constants include dimensions of a stator of the rotary electric machine, and the processor calculates coordinates of a plurality of points through which the outermost circle of the rotor passes in a coordinate system having a center of the stator as its origin, based on the gap lengths corresponding to the respective windings and the dimensions of the stator, and calculates the eccentricity of the rotary electric machine based on the calculated coordinates of the plurality of points.

[0019] According to a third aspect of the present invention, the memory stores a stator dimension (for example, stator radius (inner diameter / 2)) as a constant of the rotary electric machine. The processor calculates coordinates of a plurality of points through which the outermost circle of the rotor passes in a coordinate system having the center of the stator as the origin, based on the air gap length corresponding to each winding and the stator dimension, and calculates the eccentricity of the rotary electric machine based on the calculated coordinates of the plurality of points.

[0020] In a fourth aspect of the present invention, in the device for calculating the eccentricity of a rotating electric machine of the third aspect, it is preferable that the arithmetic formula includes a second arithmetic formula for calculating the center of a circle passing through three points from the coordinates of the three points, and the processor uses the coordinates of the three points when the calculated multiple points are three, or selects three points when the calculated multiple points are more than three, and calculates the eccentricity of the rotating electric machine using the coordinates of the selected three points and the second arithmetic formula.

[0021] The center of the circle (the rotor's outermost circle) that passes through the three points can be calculated from the coordinates of the three points, and the amount of eccentricity of the rotating electric machine (rotor) can be determined from the amount of deviation of the center of the rotor's outermost circle from the center of the stator.

[0022] A fifth aspect of the present invention provides a device for calculating eccentricity of a rotating electric machine according to the third aspect, wherein the arithmetic expression includes a second arithmetic expression for calculating the sum of the squares of the absolute values ​​of the errors obtained by substituting the coordinates of the calculated points into an equation for a circle having a radius included in the dimensions of the rotor, and the processor preferably searches for the coordinates of the center of the rotor that minimizes the sum calculated by the second arithmetic expression. The error may be a least-squares error associated with the eccentricity of the rotor. The coordinates of the center of the circle that minimizes the sum of the least-squares errors may be the coordinates of the rotor center, and the eccentricity of the rotating electric machine (rotor) can be calculated from the coordinates of the rotor center.

[0023] In a sixth aspect of the present invention, in the device for calculating eccentricity of a rotary electric machine of the third aspect, the arithmetic formula includes a second arithmetic formula for calculating a value obtained by doubling the arithmetic mean of the x coordinates and a value obtained by doubling the arithmetic mean of the y coordinates of coordinates of a plurality of points calculated from the air gap lengths of the windings at equally spaced angles, and it is preferable that the processor calculates the x coordinate and the y coordinate of the center of the rotor based on the calculated coordinates of the plurality of points and the second arithmetic formula.

[0024] In a seventh aspect of the present invention, in the first aspect of the eccentricity calculation device for a rotating electric machine, the arithmetic expression includes a first approximation expression created from a first map showing a relationship between a first direction resultant voltage, which is a sum of orthogonal projection components in the first direction of a voltage space vector calculated from a representative circumferential position and a voltage related to a magnetic flux linkage of each winding, and the eccentricity amount in the first direction, when the rotor of the rotating electric machine is eccentric in a first direction and a second direction orthogonal to the first direction and is operated under specific operating conditions; and a second approximation expression created from a second map showing a relationship between a second direction resultant voltage, which is a sum of orthogonal projection components in the second direction, and the eccentricity amount in the second direction, and a first direction resultant voltage which is the sum of orthogonally projected components in the first direction of the voltage space vector and a second direction resultant voltage which is the sum of orthogonally projected components in the second direction of the voltage space vector based on the voltage related to the calculated magnetic flux linkage corresponding to each winding and a representative circumferential position of each winding; an amount of eccentricity of the rotor in the first direction is calculated by substituting the calculated first direction resultant voltage which is the sum of orthogonally projected components in the first direction into the first approximation formula; and an amount of eccentricity of the rotor in the second direction is calculated by substituting the calculated second direction resultant voltage which is the sum of orthogonally projected components in the second direction into the second approximation formula.

[0025] The orthogonal projection components in the X-axis and Y-axis directions of the voltage space vector related to the magnetic flux linkage of each winding when the rotor is eccentric in a first direction (horizontal direction, X-axis direction) and a second direction (vertical direction, Y-axis direction) are obtained in advance, and a first approximation formula and a second approximation formula can be created from a first map and a second map of the eccentricity amount corresponding to the X-axis and Y-axis resultant voltages, which are the sums of these orthogonal projection components. The voltage related to the magnetic flux linkage is calculated from the voltage command or voltage and current command or current of each winding under the same operating conditions as when the first map and the second map were obtained, and the X-axis resultant voltage, which is the sum of the orthogonal projection components in the X-axis direction, and the Y-axis resultant voltage, which is the sum of the orthogonal projection components in the Y-axis direction, are calculated based on the voltage calculated for each winding and the representative circumferential position of each winding. Then, the X-axis direction composite voltage, which is the sum of the orthogonal projection components in the X-axis direction, is substituted into the first approximation formula to calculate the amount of eccentricity of the rotor in the X-axis direction, and the Y-axis direction composite voltage, which is the sum of the orthogonal projection components in the Y-axis direction, is substituted into the second approximation formula to calculate the amount of eccentricity of the rotor in the Y-axis direction.

[0026] An eccentricity calculation device for a rotating electric machine according to an eighth aspect of the present invention is preferably the second or seventh aspect, wherein the constant includes a phase resistance of the rotating electric machine, and the processor calculates a voltage related to the magnetic flux linkage based on the acquired voltage command or the voltage, the acquired current command or the current, and the phase resistance.

[0027] According to an eighth aspect of the present invention, the memory stores a phase resistance as a constant of the rotary electric machine, and the processor calculates a voltage related to magnetic flux linkage based on the acquired voltage command or voltage, current command or current, and phase resistance.

[0028] A ninth aspect of the present invention relates to an eccentricity calculation device for a rotary electric machine, and is related to any one of the first to eighth aspects, wherein the specific operating conditions preferably include an operating condition in which current is supplied to only specific axes of the voltage command or the voltage, which have been coordinate-transformed into the dc-qc coordinates of two orthogonal axes, and the current command or the current. This allows the voltage related to the magnetic flux linkage of an axis that is not intentionally used to be controlled to be small, and the allocation of the voltage related to the magnetic flux linkage of an axis that is used to be increased accordingly, and eccentricity information is consolidated, thereby improving the accuracy of eccentricity calculation.

[0029] A tenth aspect of the present invention provides a device for calculating eccentricity of a rotating electric machine according to any one of the first to ninth aspects, wherein the rotating electric machine is an electric motor or a generator. That is, the device can calculate the eccentricity of not only an electric motor but also a generator.

[0030] An eleventh aspect of the invention is a method executed by an apparatus for calculating eccentricity of a rotary electric machine, the apparatus including a processor and a memory storing constants and eccentricity equations for a polyphase rotary electric machine, the method including the steps of: acquiring, by the processor, voltage commands for windings of each phase of the rotary electric machine that have been coordinate-transformed into a DC-QC coordinate system for control; or acquiring voltages obtained by coordinate-transforming polyphase voltages applied to the windings of each phase into the DC-QC coordinate system for control; and acquiring, by the processor, current commands for the windings of each phase that have been coordinate-transformed into the DC-QC coordinate system for control; or acquiring currents obtained by coordinate-transforming polyphase currents flowing through the windings of each phase into the DC-QC coordinate system for control; and calculating, by the processor, the eccentricity of the rotary electric machine based on the acquired voltage commands or voltages, current commands or currents, and the constants of the rotary electric machine and the eccentricity equations stored in the memory.

[0031] A twelfth aspect of the present invention relates to a method for calculating eccentricity of a rotary electric machine in the eleventh aspect, wherein the formula includes a first formula showing a relationship between a gap length between the rotor and the stator of the rotary electric machine and a voltage related to magnetic flux linkage in a specific winding when the rotor of the rotary electric machine is eccentric with respect to a representative circumferential position of the specific winding and when the rotary electric machine is operated under specific operating conditions, the relationship being determined from a map of the air gap length and the voltage related to the magnetic flux linkage in the specific winding; and the processor preferably includes a step of calculating the voltage related to the magnetic flux linkage from the acquired voltage command or the voltage and the acquired current command or the current for each winding when the rotary electric machine is operated under the same operating conditions as the specific operating conditions, and the step of calculating the eccentricity of the rotary electric machine preferably includes determining an air gap length corresponding to each winding by substituting the calculated voltage related to magnetic flux linkage into the first formula, and calculating the eccentricity of the rotary electric machine from the determined air gap length.

[0032] A thirteenth aspect of the invention is a control device for a rotating electric machine, comprising: a control unit that controls a polyphase rotating electric machine and operates a mechanical device using the rotating electric machine; and a device for calculating eccentricity of a rotating electric machine according to any one of the first to tenth aspects.

[0033] A fourteenth aspect of the present invention provides a control device for a rotary electric machine according to the thirteenth aspect, comprising: a speed control unit that outputs a torque command based on a deviation between a preset speed command for the rotary electric machine and a speed of the rotary electric machine; a mode selection unit that selects, in response to a selection instruction from an operator, a normal operation mode for normally operating the rotary electric machine or an eccentricity calculation mode for calculating an eccentricity; a host control device that outputs a switching signal for switching between the normal operation mode and the eccentricity calculation mode based on the mode command output from the mode selection unit; and a host control device that outputs a dc-axis current command and a qc-axis current command based on the torque command and the switching signal. and a current command calculation unit that outputs a dc-axis current command and a qc-axis current command for the normal operation mode from the current command calculation unit when the normal operation mode is selected, and when the eccentricity calculation mode is selected, the control unit controls the current command calculation unit to output a dc-axis current command and a qc-axis current command for the eccentricity calculation mode, or controls the dc-axis current command and the qc-axis current command output from the current command calculation unit so that the current command becomes a steady AC current or a current that generates a voltage related to the magnetic flux linkage of the rotary electric machine.

[0034] A fifteenth aspect of the present invention is directed to a control device for a rotary electric machine, which is the thirteenth or fourteenth aspect, and which further comprises a display device that displays one or more of the eccentricity, the air gap length, and the first direction composite voltage and the second direction composite voltage, and it is preferable that the control unit causes the display device to display the eccentricity calculated by the eccentricity calculation device, the air gap length determined by the processor corresponding to each winding, and one or more of the first direction composite voltage and the second direction composite voltage calculated by the processor.

[0035] A control device for a rotating electric machine according to a 16th aspect of the present invention is, in any of the 13th to 15th aspects, preferably further comprises an abnormality warning device that warns of an abnormality in one or more of the eccentricity amount, the air gap length, the first direction composite voltage, and the second direction composite voltage, and the control unit compares one or more of the eccentricity amount calculated by the eccentricity amount calculating device, the air gap length determined by the processor corresponding to each of the windings, and the first direction composite voltage and the second direction composite voltage calculated by the processor with a threshold value that serves as an abnormality judgment criterion, and causes the abnormality warning device to warn of an abnormality when one or more of the eccentricity amount, the air gap length, the first direction composite voltage, and the second direction composite voltage are equal to or greater than the threshold value.

[0036] A seventeenth aspect of the present invention relates to a control device for a rotary electric machine, and in any one of the thirteenth to sixteenth aspects, the mechanical device is preferably a servo press machine equipped with the rotary electric machine, and the rotary electric machine rotates a main shaft of the servo press machine. [Effects of the Invention]

[0037] According to the present invention, the amount of eccentricity can be calculated with high accuracy using voltage and current values ​​acquired in a system that drives a rotary electric machine. [Brief explanation of the drawings]

[0038] [Figure 1] FIG. 1 is a diagram showing the overall configuration of a rotary electric machine control device including an eccentricity calculation device for a rotary electric machine according to the present invention, and a mechanical device including a rotary electric machine. [Figure 2] FIG. 2 is a cross-sectional view of a main part of the electric motor shown in FIG. [Figure 3] FIG. 3 is a connection diagram showing an example of connections of U-phase, V-phase, and W-phase windings of the electric motor shown in FIG. [Figure 4] FIG. 4 is a functional block diagram showing an example of the dc-qc axis current command calculation unit. [Figure 5] FIG. 5 is a block diagram showing the hardware configuration of the device for calculating the eccentricity of a rotary electric machine according to the present invention. [Figure 6]FIG. 6 is a diagram used to explain the eccentricity of the electric motor. [Figure 7] FIG. 7 is a diagram used to explain the air gap length distribution of a certain winding when the rotor is eccentric. [Figure 8] FIG. 8 is a diagram showing examples of an appropriate map and an inappropriate map. [Figure 9] Fig. 9(A) is a diagram showing the air gap length Lgk' between the stator and rotor near the k-th winding (k=1, 2, ..., Nw) for a motor with a winding number of Nw ≥ 3. Fig. 9(B) is a diagram showing the air gap lengths Lg1' and Lg2' between the stator and rotor near the first and second windings for a motor with a winding number of Nw = 2. [Figure 10] FIG. 10 is a flowchart illustrating an embodiment of a method for calculating the eccentricity of a rotary electric machine. [Figure 11] FIG. 11 is a cross-sectional view of the main part of a 6-pole, 9-slot, three-phase permanent magnet synchronous motor and a diagram showing machine dimensions. [Figure 12] FIG. 12 is a cross-sectional view of a main part of the electric motor shown in FIG. 1, showing the coil arrangement and wiring. [Figure 13] FIG. 13 is a diagram showing the relationship between the air gap length Lg1 and vqc1-Ra1×iqc1, which is a voltage related to the magnetic flux linkage in Table 1 of the first embodiment. [Figure 14] FIG. 14 is a flowchart showing a specific processing procedure performed by the control device for a rotary electric machine when the normal operation mode is selected. [Figure 15] FIG. 15(A) is a diagram showing the relationship of the X-axis direction eccentricity a1 to Vsx in [Table 6] of the second embodiment, and FIG. 15(B) is a diagram showing the relationship of the Y-axis direction eccentricity a2 to Vsy in [Table 7] of the second embodiment. [Figure 16] FIG. 16 is a cross-sectional view of the main part and machine dimensions of a three-phase squirrel-cage induction motor with 12 poles, 45 slots, and 90 rotor conductor bars. [Figure 17] FIG. 17 is a cross-sectional view of a main part of a three-phase squirrel-cage induction motor with 12 poles, 45 slots, and 90 conductor bars in the rotor, and shows the coil arrangement and wiring. [Figure 18]FIG. 18 is a diagram showing the relationship between the voltage vdc1-Ra1×idc1 and the air gap length Lg1, which is related to the magnetic flux linkage number in Table 1 of the third embodiment. [Figure 19] FIG. 19 is a diagram showing the overall configuration of a rotary electric machine control device including a rotary electric machine eccentricity calculation device according to the present invention, and a machine equipped with the rotary electric machine. [Figure 20] FIG. 20 is a cross-sectional view of a main part of the electric motor shown in FIG. [Figure 21] FIG. 21 is a connection diagram showing an example of the connection of Nw sets of windings Uk, Vk, Wk (k=1, 2, . . . , Nw) of each phase of the motor shown in FIG. [Figure 22] FIG. 22 is a diagram showing the overall configuration of a rotary electric machine control device including a rotary electric machine eccentricity calculation device according to the present invention, and a machine equipped with the rotary electric machine. [Figure 23] FIG. 23 is a schematic view of the servo press machine shown in FIG. [Figure 24] FIG. 24 is a flowchart showing an outline of a method for starting, operating, and stopping the servo press machine shown in FIG. [Figure 25] FIG. 25 is a front view showing the details of the main control panel shown in FIG. [Figure 26] FIG. 26 is an external view showing the details of the operation button box shown in FIG. [Figure 27] FIG. 27 is a diagram showing an example of a screen of the operation display provided on the main operation panel shown in FIG. 25, and is an example of a screen in the eccentricity calculation mode. [Figure 28] FIG. 28 is a diagram showing an example of the screen of the operation display when the eccentricity calculation mode is selected as the operation mode of the servo press machine, and shows the case where the "standard" motion is selected. [Figure 29] FIG. 29 is a diagram showing an example of the screen of the operation display when the eccentricity calculation mode is selected as the operation mode of the servo press machine, and shows the case where an "arbitrary" motion is selected. [Figure 30]FIG. 30 is a diagram showing an example of the screen of the operation display after the calculation of the amount of eccentricity in the "standard" motion has been completed. [Figure 31] FIG. 31 is a diagram showing an example of a screen of the operation display when the normal operation mode is selected as the operation mode of the servo press machine. [Figure 32] FIG. 32 shows the coordinates ((x1, y1), (x2, y2), ... (xNw, yNw)) of the intersection point between a circle and a group of Nw half-lines (Nw ≥ 4 and Nw is an even number) drawn at equal intervals of angle θ from the origin O. [Figure 33] FIG. 33 is a diagram showing two intersections (xk, yk) and (xm, ym) of a line lm, which is collinear with a line lk, and a circle when the group of ray lines is an even number. [Figure 34] FIG. 34 is a diagram showing the intersection point (xhk, yhk) when a perpendicular line is drawn from the center of a circle to the chord of the circle connecting the two intersection points (xk, yk) and (xm, ym) shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0039] Preferred embodiments of an apparatus and method for calculating the eccentricity of a rotary electric machine and a control device for a rotary electric machine will be described in detail below with reference to the accompanying drawings.

[0040] FIG. 1 is a diagram showing the overall configuration of a rotary electric machine control device including an eccentricity calculation device for a rotary electric machine according to the present invention, and a mechanical device including a rotary electric machine.

[0041] The rotary electric machine shown in FIG. 1 is a polyphase electric motor 110, and a mechanical device including the rotary electric machine (electric motor 110) is driven by electric motor 110.

[0042] [Electric motor] FIG. 2 is a cross-sectional view of a main part of the electric motor 110 shown in FIG.

[0043] The electric motor 110 shown in Fig. 2 is a polyphase electric motor. In Fig. 2, a typical three-phase (U-phase, V-phase, W-phase) electric motor will be described. Furthermore, although the electric motor 110 will be described as a synchronous motor, as will be described in a second embodiment below, the eccentricity calculation device and method that are the main object of the present invention can be applied regardless of the type of electric motor. Therefore, it may be an induction motor, or it may also be a generator that converts externally applied mechanical energy into electrical energy (power).

[0044] The U-phase, V-phase, and W-phase windings of the stator 110a of the electric motor 110 are each made up of a plurality of N w (≧2) windings U k , V k , W k (k=1, 2, …, N w ) are connected in series or parallel to form a set of multi-phase windings, with terminals U, V, and W leading out to a terminal box (not shown) of the motor 110. k , V k , W k (k=1, 2, …, N w ) will be called the "kth winding".

[0045] N w The windings of each phase are mutually separated by 2π / N w The k-th winding and the adjacent k-1st or k+1st winding are also spaced apart by 2π / N. w In FIG. 2, the windings of each phase are drawn without interfering with the windings of adjacent phases, but they may interfer with each other.

[0046] The electric motor 110 is also provided with a rotor 110b. A permanent magnet is embedded in the rotor 110b, and the rotor 110b is configured as the rotor 110b of a permanent magnet synchronous motor. The rotor 110b rotates at a speed synchronized with the rotating magnetic field of the stator 110a. In the example of Fig. 2, the rotor 110b has eight poles (four pole pairs).

[0047] Alternatively, the rotor may be provided with magnetic poles, each with a field winding, and exciting the field winding will generate north and south poles on the rotor. Induction motors include a wound type in which the rotor is provided with a multi-phase winding similar to the stator winding, and a squirrel-cage type in which a conducting rod is passed through the rotor's axial direction and both ends are electrically connected by a short-circuit ring. Induction motors generate electromotive force in the rotor's conducting rods when there is a difference between the speed of the rotating magnetic field on the stator side (synchronous speed) and the rotor speed, generating torque, so the rotor rotates at a slower speed than the stator's rotating magnetic field.

[0048] FIG. 3 is a connection diagram showing an example of connections of U-phase, V-phase, and W-phase windings of the electric motor shown in FIG.

[0049] Figure 3 shows the N w Although an example is shown in which the windings of each phase are connected in series, as mentioned above, this is not limiting and they may be connected in parallel.

[0050] The motor 110 has a terminal voltage v of the kth winding. uk , v vk , v wk (k=1, 2, …, N w ) can be measured at the terminal TU k and TNU k , TV k and TNV k , T.W. k and TNW k (k=1, 2, …, N w ) are provided and are drawn out to a terminal box (not shown) of the motor 110. In addition, the current i uk , i vk , i wk (k=1, 2, …, N w ) so that the terminal TU k and TNU k Between TV k and TNV k Between, T.W. k and TNW k Between (k=1, 2,…, N w ) to the current sensor S uk , S vk , S wk (k=1, 2, …, Nw ) are provided respectively.

[0051] In the case of Figure 3, it is possible to use one current sensor for each phase.

[0052] [Control device for rotating electric machines] In FIG. 1, a control device for a rotary electric machine includes an eccentricity calculation device for a rotary electric machine according to the present invention.

[0053] The electric motor 110 is provided with a drive shaft 112 on the side (load side) of the rotor that is connected to a mechanical device, and the drive shaft 112 is connected to the mechanical device.

[0054] 1 shows a servo press machine 100 as an example of the mechanical device. Details of the servo press machine 100 will be described in a sixth embodiment below. The mechanical device is not limited to the servo press machine 100, and may be, for example, an electric railcar, an automobile, a crane, or other industrial machinery such as construction machinery. Also, there may be no mechanical device and the device may be a single electric motor.

[0055] The motor position sensor 116 detects the position of the motor 110 and is attached to the motor 110. In FIG. 1, it is attached to a rotating shaft coaxial with the drive shaft 112 of the motor 110, but this is not limiting and it may be attached to a mechanical device mechanically linked to the rotating shaft. A rotary encoder or the like is used as the motor position sensor 116. The detected position is used for coordinate conversion calculations and speed control calculations in well-known vector control. Furthermore, although the present example is described as a configuration provided with the motor position sensor 116, a system in which the position is estimated and calculated from information such as the voltage and current of the motor, as in position sensorless control, may also be used.

[0056] The control device for the rotary electric machine includes a current control device 220 for controlling the current of the electric motor 110 .

[0057] The current control device 220 includes a current control unit 230, a three-phase AC power supply 240, a converter 250, a servo amplifier (inverter) 260, a PWM (Pulse Width Modulation) conversion unit 270, and a current sensor 280.

[0058] The three-phase AC voltage command (v uc * , v vc * , v wc * ) is output to PWM conversion unit 270, where it is PWM converted and applied to servo amplifier 260. To the other input of servo amplifier 260, three-phase AC power from three-phase AC power supply 240 is converted to DC power by converter 250, and the DC power is applied from converter 250. Servo amplifier 260 is a device that converts DC power to three-phase AC power, and is a well-known inverter. Servo amplifier 260 converts the DC power to three-phase AC power in accordance with the PWM-converted three-phase AC voltage command, and applies the converted three-phase AC power to electric motor 110 to drive electric motor 110.

[0059] The control device for a rotary electric machine of this example has a normal operation mode for operating the electric motor 110 normally and an eccentricity calculation mode, and the mode selection unit 212 outputs a mode command M indicating the normal operation mode or the eccentricity calculation mode in response to a selection instruction from an operator. * is output to the upper control device 210.

[0060] The upper control device 210 receives a mode command M indicating the normal operation mode from the mode selection unit 212. * When this command is input, the brake control command Bc * is output to the brake control unit 172, and the brake 170 is opened by the brake control unit 172, after which the electric motor 110 is operated normally.

[0061] Furthermore, the upper control device 210 receives a mode command M indicating the eccentricity calculation mode from the mode selection unit 212. * When the brake control command Bc is input, the brake 170 is opened or closed.* is output to the brake control unit 172, and after the brake 170 is opened or closed by the brake control unit 172, the operation of the electric motor 110 is set to an operation for calculating the amount of eccentricity.

[0062] Next, a speed control and current control (vector control) system for the electric motor 110 will be briefly described.

[0063] A speed command N preset from the upper control device 210 * is output to the positive input of the adder. The speed N calculated by the speed calculation unit 214 is added to the negative input of the adder, and the adder outputs the speed command N * and the deviation between the speed N (N * -N) and calculate the deviation (N * -N) to the speed control unit 213. The speed calculation unit 214 outputs the position θ re The speed N is calculated based on the above.

[0064] The speed control unit 213 calculates the deviation (N * -N) according to the torque command T * The torque command T is output. * is input to the dc-qc axis current command calculation unit 216.

[0065] FIG. 4 is a functional block diagram showing an example of the dc-qc axis current command calculation unit.

[0066] Another input to the dc-qc axis current command calculation unit 216 is a switching signal Mdq from the upper control device 210 for switching between the normal operation mode and the eccentricity calculation mode. * is added, and the switching signal Mdq * In the case of a signal for switching to the eccentricity calculation mode, the dc-axis current command and qc-axis current command calculation unit 216A for the eccentricity calculation mode is selected, and the dc-axis current command i for the eccentricity calculation mode is dc * , qc axis current command i qc * (Fig. 4(A)), and the switching signal Mdq *In the case of a signal for switching to the normal operation mode, the dc-axis current command and qc-axis current command calculation unit 216B for the normal operation mode is selected, and the dc-axis current command i for the normal operation mode is calculated. dc * , qc axis current command i qc * (Figure 4(B)).

[0067] In normal operation mode, the dc-axis current command i dc * For example, it may be commanded to be 0, or it may be commanded to have maximum torque, maximum efficiency, and power factor = 1. qc * is the torque command T * is calculated from the torque equation of the electric motor 110, for example, and is issued as a command.

[0068] Output in eccentricity calculation mode i dc * , i qc * More on this later.

[0069] Returning to FIG. 1, the dc-qc axis current command i output from the dc-qc axis current command calculation unit 216 dc * , qc axis current command i qc * is input to the current control section 230 and added to the positive input of each adder in the current control section 230. The dc-axis current i dc , qc axis current i qc The coordinate conversion unit 236 is a part that performs polyphase / dc-qc conversion, and converts the three-phase AC current (i u , i v , i w ) and the position θ obtained by the motor position sensor 116 re Using the dc axial current i dc , qc axis current i qc As mentioned above, the position θ re Alternatively, position sensorless control may be used, and values ​​estimated and calculated from voltage and current information may be used.

[0070] dc axis current command i dc * and dc axial current i dc The adder that inputs the dc axis current command i dc * and dc axial current i dc deviation from (i dc * -i dc ) and calculate the deviation (i dc * -i dc ) to the dc-axis current control unit 232, and the qc-axis current command i qc * and qc axis current i qc The adder that inputs the qc-axis current command i qc * and qc axis current i qc deviation from (i qc * -i qc ) and calculate the deviation (i qc * -i qc ) is output to the qc-axis current control unit 234.

[0071] The dc-axis current control unit 232 calculates the input deviation (i dc * -i dc ) based on the DC axis voltage command V dc * The qc-axis current control unit 234 outputs the input deviation (i qc * -i qc ) based on the QC axis voltage command V qc * Output.

[0072] The dc-axis current control section 232 and the qc-axis current control section 234 are configured by connecting, for example, a proportional controller (P control) and an integral controller (I control) in parallel, but the present invention is not limited to this configuration because the main purpose of the present invention is to calculate the amount of eccentricity. A differential controller (D control) may also be added in parallel to configure a so-called PID control. dc * Nii dc follows, and i qc* Nii qc Any controller having a configuration for controlling the speed so that the speed follows the speed may be used.

[0073] DC axis voltage command V dc * , qc-axis voltage command v qc * is applied to the coordinate conversion unit 238. The coordinate conversion unit 238 is a part that performs dc-qc / polyphase conversion, and the dc-axis voltage command v dc * , qc-axis voltage command v qc * and the position θ obtained from the motor position sensor 116. re Using the three-phase AC voltage command v uc * , v vc * , v wc * As mentioned above, the position θ re Alternatively, position sensorless control may be used, and values ​​estimated and calculated from voltage and current information may be used.

[0074] 3-phase AC voltage command v uc * , v vc * , v wc * As described above, the signal is PWM converted by the PWM conversion unit 270 and then output to the servo amplifier 260, where it is amplified and output to the electric motor 110. As a result, the electric motor 110 is subjected to current control (vector control).

[0075] The above is essentially the same for polyphase AC of three or more phases, as long as the polyphase AC current is subjected to coordinate transformation synchronized with the rotor to generate a two-dimensional current vector, which is then controlled, and it goes without saying that the configuration is not limited to three phases, and is not limited to three phases.

[0076] In addition, the control device of the rotating electric machine is the terminal voltage v of the k-th winding mentioned above. uk , v vk , v wk and the winding current i uk , ivk , i wk (k=1, 2, …, N w The voltage and current measuring unit 331 measures the voltage and current at the terminal TU of the motor 110. k and TNU k , TV k and TNV k , T.W. k and TNW k , respectively N w One end of the voltage sensor cable for each phase is connected to the terminal TU k and TNU k Between TV k and TNV k Between, T.W. k and TNW k Current sensor S installed between uk , S vk , S wk are N w One end of each of the current sensor cables for each of the phases is connected to the voltage / current measuring unit 331, and the other end of each of the sensor cables is connected to the voltage / current measuring unit 331, which measures the voltage v uk , v vk , v wk and the winding current i, which is a multiphase current flowing through the k-th winding of each phase uk , i vk , i wk (k=1, 2, …, N w ) is measured.

[0077] The control device of the rotating electric machine also calculates the terminal voltage v of the kth winding. uk , v vk , v wk and the winding current i uk , i vk , i wk (k=1, 2, …, N w ) and the position θ obtained by the motor position sensor 116 re Using this, the DC axis voltage of the kth winding, v dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck (k=1, 2, …, N w ) is provided with a coordinate conversion unit 340 that performs rotational coordinate conversion to the position θ reA value estimated and calculated from voltage and current information or the like may be used for the position value, and the position value acquired by the motor position sensor 116 is not necessarily required.

[0078] However, if the position acquired value of the motor position sensor 116 is not used, it is necessary to simultaneously measure the voltage and current acquired values ​​of each winding to clarify the phase relationship between the voltage and current of each winding. This is because the position θ common to all windings is calculated in the rotation coordinate transformation calculation described later. re This is because it is necessary to perform coordinate transformation calculations using the above. When simultaneous measurement of all windings is difficult and, for example, only two windings can be measured simultaneously, the same effect as when all windings are measured simultaneously can be obtained by using one winding as a reference and measuring the other windings at the same time as the reference winding. Furthermore, the voltage / current measuring unit 331 and / or the coordinate transforming unit 340 are not limited to those provided in the control device of the rotating electric machine, but may also be provided in the eccentricity calculating device for the rotating electric machine.

[0079] The eccentricity calculation device 300 calculates the air gap length L between the stator and rotor near the k-th winding. gk (k=1, 2, …, N w The air gap length calculation unit 310 may be replaced with a composite voltage calculation unit 320 that calculates the X-axis resultant voltage (first direction composite voltage) Vsx, which is the sum of the components of the voltage space vectors related to the magnetic flux linkage of each winding orthogonally projected in the X-axis direction, and the Y-axis resultant voltage (second direction composite voltage) Vsy, which is the sum of the components of the voltage space vectors related to the magnetic flux linkage of each winding orthogonally projected in the Y-axis direction. Alternatively, both the air gap length calculation unit 310 and the composite voltage calculation unit 320 may be provided. The composite voltage calculation unit 320 regards the voltage related to the magnetic flux linkage of each winding as a space vector quantity at a winding representative position (angle), orthogonally projects the voltage space vectors related to the magnetic flux linkage of each winding in a first direction (horizontal direction (X-axis direction)) and a second direction (vertical direction (Y-axis direction)) perpendicular to the first direction, and calculates an X-axis resultant voltage (first direction composite voltage) Vsx, which is the sum of the components of the voltage space vectors related to the magnetic flux linkage of each winding orthogonally projected in the Y-axis direction.

[0080] The eccentricity calculation device 300 calculates the v of the k-th winding input from the coordinate conversion unit 340. dck , v qck , i dck , i qck(k=1, 2, …, N w The eccentricity (a1, a2) is calculated using the values ​​of the motor constants, which are constants of the rotating electric machine, and a first equation (approximation equation) that shows the relationship between the gap length between the stator and rotor near the windings, which is an equation that can be calculated in advance, and the voltage related to the magnetic flux linkage, or by calculating the horizontal (X-axis) and vertical (Y-axis) orthogonal projection components of the voltage space vector related to the magnetic flux linkage of each winding, and then using equations (first approximation equation, second approximation equation) obtained from the map of the eccentricity of the two axes that are orthogonal to the X-axis resultant voltage Vsx and the Y-axis resultant voltage Vsy, which are their sums. The method for calculating the eccentricity will be described later.

[0081] The eccentricity amount display device 350, which is a display device, displays the calculated eccentricity amount (a1, a2), and the eccentricity amount (a1, a2), the air gap length L of the k-th winding. gk (k=1, 2, …, N w ), the X-axis direction composite voltage Vsx, and the Y-axis direction composite voltage Vsy, one or more of these values ​​may be displayed.

[0082] The abnormality alarm device 360 ​​calculates the eccentricity (a1, a2) input from the eccentricity calculation device 300, the air gap length L of the k-th winding, gk (k=1, 2, …, N w ), the X-axis direction composite voltage Vsx, and the Y-axis direction composite voltage Vsy are compared with a threshold value that serves as an abnormality judgment criterion, and if the voltage is less than the threshold value, a "normal" is output, and if the voltage is equal to or greater than the threshold value, an "abnormal" is output. The eccentricity amount display device 350 and the abnormality warning device 360 ​​may be the same device. Furthermore, as will be shown in a sixth embodiment described later, the eccentricity amount and the warning content may be displayed on the operation display on the main operation panel of the servo press machine 100.

[0083] [Hardware configuration of the device for calculating the eccentricity of rotating electric machines] FIG. 5 is a block diagram showing the hardware configuration of the device for calculating the eccentricity of a rotary electric machine according to the present invention.

[0084] 5 is configured by, for example, a computer, and includes a processor 370, a memory 380, and an input / output interface 390. This eccentricity calculation device 300 is incorporated into the control device of the rotating electric machine as shown in FIG.

[0085] The processor 370 is composed of a CPU (Central Processing Unit) and the like, and executes various programs including firmware and a program for calculating the amount of eccentricity stored in the memory 380, controls the various parts of the eccentricity calculation device, executes processing for calculating the amount of eccentricity, and functions as the air gap length calculation part 310, composite voltage calculation part 320, and eccentricity calculation part 330 shown in FIG. 1.

[0086] The memory 380 includes a flash memory, a read-only memory (ROM), a random access memory (RAM), a hard disk drive, etc. The flash memory, the ROM, or the hard disk drive is a non-volatile memory that stores various programs including firmware.

[0087] The RAM functions as a work area for processing by the processor, and also temporarily stores programs and the like stored in flash memory, etc. The processor 370 may have part of the memory 380 (RAM) built in.

[0088] The memory 380 also stores the motor constants and eccentricity calculation formulas for the motor 110. The motor constants include the phase resistance Ra of the motor 110 and the dimensions of the motor 110 (stator, rotor).

[0089] Furthermore, the memory 380 stores measurement data (in this example, the terminal voltage v of the k-th winding measured by the voltage / current measuring unit 331) during the current control of the electric motor 110. uk , v vk , v wk , winding current i uk , i vk , i wk (k=1, 2, …, N w)), the position θ obtained from the motor position sensor 116 re , and the DC axis voltage v of the kth winding transformed from them dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck , (k=1, 2, ..., N w ), and the air gap length L of the kth winding calculated from the motor constants and measurement data. gk (k=1, 2, …, N w ), the X-axis direction composite voltage Vsx, and the Y-axis direction composite voltage Vsy, and when the amount of eccentricity is calculated, it functions as a storage device that stores the amount of eccentricity.

[0090] The input / output interface 390 inputs various measurement data and outputs the data to the eccentricity display device 350 and the abnormality alarm device 360. The input / output interface 390 is also connected to the upper control device 210, and is capable of transmitting and receiving necessary information to and from the upper control device 210.

[0091] The host controller 210 can also be configured by a computer. In this case, the host controller 210 and the eccentricity calculation device 300 may be configured by the same computer or by separate computers.

[0092] <First embodiment of device and method for calculating eccentricity of a rotary electric machine> The processor 370 calculates the terminal voltage v of the k-th winding, which is acquired during current control in the eccentricity calculation mode of the electric motor 110 and stored in the memory 380. uk , v vk , v wk , winding current i uk , i vk , i wk (k=1, 2, …, N w ) and the position θ obtained from the motor position sensor 116 re , and the DC axis voltage v of the kth winding transformed from them dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck , (k=1, 2, ..., Nw ), and the motor constants and the calculation formula for the eccentricity amount stored in advance in the memory 380 are used to calculate the eccentricity amount (a1, a2), the air gap length L of the kth winding. gk (k=1, 2, …, N w ), the X-axis direction composite voltage Vsx, and the Y-axis direction composite voltage Vsy are calculated. The calculated eccentricity (a1, a2), the air gap length L of the kth winding gk (k=1, 2, …, N w ), the X-axis direction composite voltage Vsx, and the Y-axis direction composite voltage Vsy are output to the eccentricity amount display device 350 and the abnormality alarm device 360.

[0093] Terminal voltage v of the kth winding uk , v vk , v wk is converted into the dc-qc coordinate value v by the coordinate conversion unit 340. dck , v qck The conversion formula is as follows:

[0094]

number

[0095] where: v dck : DC axis voltage of the kth winding (k=1, 2, ..., N w ) v qck : qc-axis voltage of the kth winding (k=1, 2, ..., N w ) v uk : U-phase voltage of the kth winding (k=1, 2, ..., N w ) v vk : V-phase voltage of the kth winding (k=1, 2, ..., N w ) v wk : W-phase voltage of the kth winding (k=1, 2, ..., N w ) θ re The position may be a position (electrical angle) detected by the motor position sensor 116 or a position estimated and calculated from voltage and current information, or a position at a certain angle φ (φ is arbitrary) from such a detected or estimated position.

[0096] Also, the winding current i of the kth winding uk , i vk , i wk is converted into the qc coordinate value i by the coordinate conversion unit 340. dck , i qck The conversion formula is as follows:

[0097]

number

[0098] where: i dck : dc axis current of the kth winding (k=1, 2, ..., N w ) i qck : qc-axis current of the kth winding (k=1, 2, ..., N w ) i uk : U-phase current of the kth winding (k=1, 2, ..., N w ) i vk : V-phase current of the kth winding (k=1, 2, ..., N w ) i wk : W-phase current of the kth winding (k=1, 2, ..., N w ) θ re The position (electrical angle) may be the position detected by the motor position sensor 116, or the position estimated from voltage and current information, or the position at a certain angle difference φ (φ is arbitrary) from the detected or estimated position. However, the value v of the dc-qc coordinates dck , v qck It goes without saying that the same value of φ as when calculating

[0099] Next, a method for calculating the amount of eccentricity will be described.

[0100] When the rotor of an electric motor is eccentric, the air gap length between the stator and rotor near a certain winding changes compared to when it is not eccentric. In other words, the magnetic resistance of the magnetic circuit through which the interlinkage magnetic flux of a certain winding passes changes, so the magnetic flux linkage of a certain winding changes. Therefore, the voltage related to the magnetic flux linkage changes.

[0101] To explain this, Figure 6 shows an example of a four-pole motor in which two sets of windings, the first winding (windings U1, V1, W1) and the second winding (windings U2, V2, W2), are arranged at intervals of π.

[0102] In the case of no eccentricity shown in Figure 6(A), the air gap length L between the stator and rotor near the first winding g1 and the air gap length L between the stator and rotor near the second winding g2 L g1 =L g2 =L ga Therefore, when the same current flows through the primary and secondary windings, the voltages related to the magnetic flux linkages of the primary and secondary windings will be the same.

[0103] In the case of eccentricity in Figure 6(B), the rotor position changes with eccentricity compared to before eccentricity. For example, if the rotor becomes eccentric in the direction of the first winding, L g1 <L ga <L g2 For this reason, the air gap length near the primary winding is smaller than when there is no eccentricity, and the magnetic resistance is smaller, so when equal currents flow through the primary and secondary windings, the absolute value of the voltage related to the magnetic flux linkage becomes larger, and conversely, it becomes smaller in the secondary winding.

[0104] The same is true for a motor with a larger number of windings. Therefore, when there is eccentricity, the value of the voltage related to the magnetic flux linkage of each winding of the motor changes compared to when there is no eccentricity.

[0105] The basic idea of ​​the eccentricity calculation method of the present invention is to calculate the v of each winding of the motor. dck , v qck , i dck , i qckBy acquiring and analyzing the air gap length L of the kth winding, gk (k=1, 2, …, N w ), or the X-axis resultant voltage Vsx, which is the sum of the components of the voltage space vectors related to the magnetic flux linkage of each winding projected orthogonally in the X-axis direction, and the Y-axis resultant voltage Vsy, which is the sum of the components of the voltage space vectors related to the magnetic flux linkage of each winding projected orthogonally in the Y-axis direction, and the amount of eccentricity is calculated from the results.

[0106] The procedure is outlined below.

[0107] (1) As pre-measurement data or pre-analysis data for calculating the eccentricity, the DC shaft voltage V of each winding under specific operating conditions (certain operating conditions) when the eccentricity (a1, a2) of the motor is changed. dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck , and motor constant (phase resistance R ak ) the voltage v related to the magnetic flux linkage dck -R ak ×i dck , or v qck -R ak ×i qck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) corresponding to the vector sum of the air gap length L between the stator and rotor near the kth winding. gk or an approximate expression (first approximate expression) of a map of the X-axis direction eccentricity a1 corresponding to the X-axis direction composite voltage Vsx, which is the sum of the components obtained by orthogonally projecting the voltage space vectors related to the magnetic flux linkage of each winding in the X-axis direction, and an approximate expression (second approximate expression) of a map of the Y-axis direction eccentricity a2 corresponding to the Y-axis direction composite voltage Vsy, which is the sum of the components obtained by orthogonally projecting the voltage space vectors related to the magnetic flux linkage of each winding in the Y-axis direction.

[0108] Gap length L gkThe approximation formula that can be obtained from the map and the formula for obtaining the composite voltages Vsx and Vsy, which are the sum of the orthogonal projection components, are the first formula for obtaining the amount of eccentricity.

[0109] (2) Any eccentricity of the motor (a1 ' ,a2 ' To find the eccentricity (a1 ' ,a2 ' ) DC axial voltage V of each winding dck ', qc axis voltage v qck ', dc axis current i dck ', qc axis current i qck ' and the motor constants, and using these and the first calculation formula obtained in advance, the air gap length L of each winding is calculated. gk ' or the sum of the components of the voltage space vectors related to the magnetic flux linkage of each winding in the X-axis and Y-axis directions, calculated as the X-axis resultant voltage Vsx' and the Y-axis resultant voltage Vsy'. Then, gk ', or the X-axis direction composite voltage Vsx', the Y-axis direction composite voltage Vsy', and the second equation for calculating the eccentricity amount, ' ,a2 ' ) is calculated.

[0110] The second equation is an equation for calculating the amount of eccentricity by finding the point through which the outermost circle of the rotor passes from the air gap length, and an approximation equation (first approximation equation) for a map of the amount of eccentricity in the X-axis direction a1 corresponding to the resultant X-axis voltage Vsx, which is the sum of the components of the voltage space vector related to the magnetic flux linkage of each winding when orthogonally projected in the X-axis direction, and an approximation equation (second approximation equation) for a map of the amount of eccentricity in the Y-axis direction a2 corresponding to the resultant Y-axis voltage Vsy, which is the sum of the components of the voltage space vector related to the magnetic flux linkage of each winding when orthogonally projected in the Y-axis direction.

[0111] The method for calculating the amount of eccentricity will be described in detail below.

[0112] In the first embodiment, a method for calculating the amount of eccentricity using the air gap length calculated by the air gap length calculation unit 310 will be described, and in the second embodiment, a method for calculating the amount of eccentricity using the composite voltage, which is the sum of voltage space vectors of voltages related to the magnetic flux linkage of each winding orthogonally projected in the X-axis and Y-axis directions and calculated by the composite voltage calculation unit 320, will be described.

[0113] [The air gap length L between the stator and rotor near the kth winding gk [Making a map of voltage related to magnetic flux linkage when As mentioned above, when the rotor is eccentric, the air gap length between the stator and rotor changes. Here, even if we are talking about the air gap length between the stator and rotor near a certain winding, as shown in Figure 7, for the first winding of a two-winding motor, the UVW phase windings that make up a certain winding are spatially distributed, so the air gap length L between the stator and rotor near each of the UVW phase windings of the first winding g1u , L g1v , L g1w are not equal.

[0114] However, since the voltage value in the air gap length distribution (corresponding to a certain eccentricity) of a certain winding of the motor is obtained as a single value, the air gap length L between the stator and rotor near the kth winding gk (k=1, 2, …, N w ) is a representative circumferential position (angle) θ that represents the spatially distributed void length. rmck (k=1, 2, …, N w ) can be used as the gap length.

[0115] Representative circumferential position (angle) θ rmck As one method of determining the representative circumferential position (angle) θ rmck It has been found that if the above equation is determined, the gap length (amount of eccentricity) at any amount of eccentricity, which will be described later, can be calculated with high accuracy.

[0116] ``Representative circumferential position (angle) θ rmckis the center of gravity position (angle) of the entire coil that makes up a certain winding A, which is calculated from the circumferential position (angle) of each slot in which a certain winding A is housed and the amount of winding A housed in each slot. We will now explain the amount of winding. For example, in the case of two-layer distributed winding, there are cases where a certain winding A is placed in both layers of slot B, and cases where it is placed in only one layer of slot C. In this case, the amount of winding A in slot B is 2, and the amount of winding A in slot C is 1. Furthermore, another winding D is placed in slot C with a winding amount of 1.

[0117] It is not necessarily clear whether the above method of determining the representative circumferential position (angle) is theoretically superior, but simply put, since voltage is generated in the winding, the center of gravity position (angle) of the entire winding at the circumferential position (angle) of each slot in which a certain winding is housed is determined as the representative circumferential position (angle) θ rmck I think it is not off the mark to say this.

[0118] In the first embodiment, the representative circumferential position (angle) θ rmck Decide.

[0119] Representative circumferential position θ of the kth winding of the motor rmck After calculating the above, the representative circumferential position (angle) θ of each winding under certain operating conditions is calculated. rmck The rotor of the motor is eccentric along the line above, and the air gap length L between the stator and rotor when the eccentricity (a1, a2) is changed gk The corresponding DC shaft voltage V dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck (k=1, 2, …, N w ) is obtained by measurement or analysis. From these values, the voltage related to the magnetic flux linkage, v dck -R ak ×i dck , or v qck -R ak ×i qck , or (v dck -R ak ×idck , v qck -R ak ×i qck ) and calculate the vector sum of v dck -R ak ×i dck , or v qck -R ak ×i qck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) corresponding to the vector sum of the air gap length L between the stator and rotor near the kth winding. gk The maps are calculated respectively.

[0120] where v dck , v qck or (v dck ,v qck ), but v dck -R ak ×i dck , v qck -R ak ×i qck , or (v dck -R ak ×i dck ,v qck -R ak ×i qck ) is used as the vector sum for the following reasons.

[0121] The eccentricity calculation method of the present invention utilizes the fact that the number of magnetic flux linkages that link the windings of the motor changes due to eccentricity, and as a result, the voltage and current of the motor change. ak ×i dck , R ak ×i qck is unrelated to the magnetic flux linkage inside the motor, so by subtracting this, we obtain the voltage related to the magnetic flux linkage, v dck -R ak ×i dck , v qck -R ak ×i qck This is to obtain dck -R ak ×i dck , vqck -R ak ×i qck It will be obvious to those skilled in the art that is a voltage related to the magnetic flux linkage in polyphase AC motors in general.

[0122] Also, R ak ×i dck , R ak ×i qck By taking this into consideration, the amount of eccentricity can be calculated accurately even for a motor in which multiple polyphase windings are drawn out from the motor, as will be shown in the examples described later. For example, if one of multiple polyphase windings is located above the motor and another is located below, and the terminal box of the motor is also located above, the upper polyphase winding has a smaller phase resistance value than the lower polyphase winding because the distance to the terminal box is shorter. Therefore, the voltage drop (R ak ×i dck , R ak ×i qck ) differs between the upper and lower polyphase windings, so by taking this into consideration, the voltage related to the magnetic flux linkage can be measured or analyzed correctly, and the amount of eccentricity can be calculated with high precision.

[0123] When measuring the voltage between the terminals of the multiple windings constituting each phase of a motor in which only one polyphase winding is drawn out to the outside of the motor, such as the motor shown in Figs. 11 and 12 used in verifying the first embodiment of the present invention, or the motor in Patent Document 1, the terminals provided for measuring the amount of eccentricity are provided separately from the terminals drawn out to the outside of the motor for connection to the power supply. In this case, the terminal TU for measuring the amount of eccentricity k and TNU k During k and TNV k Between k and TNW k The resistance between the two can be set to approximately the same value, and the voltage drop is not taken into consideration. dck , or v qck , or (v dck , v qck A map of the vector sum of ( ) and the void length may be created.

[0124] Alternatively, with reference to Patent Document 1, if the shape and design specifications of a rotating electric machine are determined, it is considered that the relationship between the winding terminal voltage and the eccentricity (corresponding to the air gap length of each winding in this specification) is the same if the measurement conditions are the same, and the phase resistance R of the first winding of a certain electric motor A and an electric motor B that has the same shape and design specifications is a1 , dc axial voltage v dc1 , qc-axis voltage v qc1 , (v dc1 ,v qc1 The vector sum of the phase resistance R of the first winding of motor A is a1 , dc axial voltage v dc1 , qc-axis voltage v qc1 , (v dc1 ,v qc1 ) and the phase resistance R of the second winding of motor B. a2 , dc axial voltage v dc2 , qc-axis voltage v qc2 , (v dc2 ,v qc2 The vector sum of R of the second winding of motor A is a2 , dc axial voltage v dc2 , qc-axis voltage v qc2 , (v dc2 ,v qc2 ) and each is equal to the vector sum of..., and "for each winding" v dck or v qck The air gap length map may be calculated independently, and the air gap length near each winding may be calculated using the map for the corresponding winding. dck or v qck You only need to consider the number of maps, but you will need to have multiple maps.

[0125] v dck -R ak ×i dck and the gap length L gk Map of v qck -R ak ×i qck and the gap length L gk map of (v dck -R ak ×i dck , v qck -R ak ×i qck ) and the gap length L gkAny one of the maps above will suffice, and the appropriate one should be used. Also, if each winding of the motor is wound in the same way and evenly spaced in the circumferential direction, it is only necessary to create a map for only one winding, and the same map can be used for the other windings.

[0126] Figure 8 shows examples of maps in an appropriate case and an inappropriate case.

[0127] The most appropriate case is when the map can be approximated by a linear function. Next, when it can be approximated by a monotonically increasing or monotonically decreasing function, it can also be used in applications where the calculation accuracy of the air gap length (eccentricity amount) does not need to be very high. The latter type of map occurs when, for example, the air gap length is small and magnetic saturation causes nonlinear magnetic characteristics. Even in this case, accuracy can be increased if the map is used within the range where it can be approximated by a linear function.

[0128] It is not appropriate if it has an inflection point or if it has the same v dck -R ak ×i dck , or v qck -R ak ×i qck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) there are two or more corresponding gap lengths for the vector sum. The former is susceptible to measurement error, while the latter makes it impossible to determine the amount of eccentricity in the first place.

[0129] After the map is calculated, v dck -R ak ×i dck , or v qck -R ak ×i qck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) as a vector sum of the gap length L gk Find a function (i.e., an approximate expression) of

[0130]

number

[0131]

number

[0132]

number

[0133] [Any eccentricity (a1 ' ,a2 ' ) the gap length L gk Calculation of ' Any eccentricity of the motor (a1 ' ,a2 ' ) the air gap length L between the stator and rotor near the kth winding of the motor gk ' (k=1, 2, …, N w ) for each winding under the same operating conditions as when the map was obtained. dck ', v qck ',i dck ',i qck ' is determined by measurement or analysis.

[0134] Next, from these values, v dck '-R ak ×i dck ', or v qck '-R ak ×i qck ', or (v dck '-R ak ×i dck ', v qck '-R ak ×i qck ') to calculate the vector sum. And, v in equation (3) dck -R ak ×i dck To, v dck '-R ak ×i dck Substitute ', or v in equation (4) qck -R ak ×i qck To, v qck '-R ak ×i qck ', or (v dck -R ak ×i dck , v qck -R ak ×i qck ) vector sum, (v dck '-R ak ×i dck ', v qck '-R ak ×i qck Substitute the vector sum of L gk L gk ', the representative circumferential position (angle) of each winding is θ rmck The gap length L gk ' is required.

[0135] [Any eccentricity (a1 ' ,a2 ' ) calculation] The kth winding of the motor (k=1, 2, ..., N w ) the air gap length L between the stator and rotor in the vicinity gk Once ' is found, the multiple points (N w points) can be found.

[0136] Number of windings is N w (N w The case of the electric motor of type ≧3) will be explained with reference to FIG. 9(A).

[0137] Number of windings is N w (N w ≧3), the points on the outermost circumference of the rotor are P1, P2, ..., Pk, ..., PN in Figure 9(A). w N wBy arbitrarily selecting three points from these points, the outermost circle of one rotor can be determined according to the geometric theorem that "every triangle has a circumscribing circle." Then, the center of the circumscribing circle can be found from the three points. By finding the center of the circle, the eccentricity (a1 ' ,a2 ' ) can be determined as a single point. This method is referred to as the "three-point method" in this specification.

[0138] Now, if the coordinates of the three points are (x1, y1), (x2, y2), and (x3, y3), in the case of the "three-point method," the eccentricity amount (a1', a2') can be calculated using the following formula.

[0139]

number

[0140] However, when there are a large number of windings, there are many combinations in which three points are selected from the points on the outermost circle. In theory, points other than the three selected should also be on the outermost circle that was initially determined, but due to the influence of the difference between the ideal motor stator or rotor shape (a perfect circle) and the actual motor shape (a shape that is distorted from a perfect circle), it is possible that they may not be on the outermost circle that was initially determined. Therefore, the eccentricity (a ' ,a2 ' ) and taking the average value, it is thought that the accuracy of the eccentricity amount can be improved. However, this calculation becomes enormous if there are many combinations of three points to select.

[0141] Therefore, the center point (a1 ' ,a2 ' ), the equation of a circle of radius r (x-a1 ' ) 2 +(y-a2 ' ) 2 =r 2 In this case, all points P1(x1,y1), P2(x2,y2), ..., Pk(x k ,y k ), …, PN w (x Nw ,y Nw ) satisfies the equation of the circle, a1' , a2 ' , r may be calculated by a numerical analysis method. In this case, various numerical analysis methods are conceivable. For example, 2 is moved to the left side (x-a1') 2 +(y-a2') 2 -r 2 If the point (x, y) is on the circle at = 0, the value on the left side will be 0 on the right side. Substitute the point on the left side where the outermost circle passes through, and find the point a1 where the sum of the squares of the absolute values ​​of the errors between this and 0 on the right side is minimum. ' , a2 ' , r can be found by the least squares method shown in the following equation.

[0142]

number

[0143] If the radius r of the outermost circle of the rotor is a known value, use r as a constant in equation (7) and calculate a ' , a2 ' Just explore.

[0144] This method is referred to as a "numerical analysis method" in this specification.

[0145] Alternatively, the eccentricity (a1 ' ,a2 ' ) may be obtained.

[0146] [Theorem 1] A circle (equation of the circle: (x-a1 ' ) 2 +(y-a2 ' ) 2 =r 2 ) and N, which is drawn at equal intervals of angle θ from the origin O of the XY coordinate system with the center of the stator as the origin O. w pieces(N w ≧4 and N w The coordinates of the intersections with the group of lines (x1, y1), (x2, y2), ..., (x k ,y k ), …, (x Nw,y Nw ), the coordinates of the center point of the circle (a1 ' ,a2 ' ) is expressed by the following formula:

[0147]

number

[0148] N w N w If the radius of the circle is an odd number ≧3, then equation (8) does not hold. However, if the radius of the circle is ' ,a2 ' ) vector sum √(a1 '2 +a2 '2 ), if it is large enough, this approximately holds. That is, the following theorem holds:

[0149] [Theorem 2] A circle (equation of the circle: (x-a1 ' ) 2 +(y-a2 ' ) 2 =r 2 ) and N drawn at equal intervals of angle θ from the origin O w pieces(N w ≧3 and N w The coordinates of the intersections with the group of lines (x1, y1), (x2, y2), ..., (x k ,y k ), …, (x Nw ,y Nw ), the coordinates of the center point of the circle (a1 ' ,a2 ' ) is the radius of the circle r, and the coordinates of the center point of the circle (a1 ' ,a2 ' ) vector sum √(a1 '2 +a2 '2 ) is expressed by the following equation when it is sufficiently large.

[0150]

number

[0151] Theorems 1 and 2 were predicted by the inventor from the results of numerical experiments conducted on various cases, and were later mathematically proven by the inventor himself. As far as the inventor has researched, there is no mention of them in publicly known literature, and it is believed that there would be no motivation to discover these theorems unless one's task is to calculate the eccentricity of an electric motor, as the inventor has done, and therefore the inventor believes that they are novel theorems of geometry. Even if this theorem were publicly known, as will be described later, it would be impossible to prove it by dividing a group of semi-linear lines at equally spaced angles into the representative circumferential position (angle) θ of each winding. rmck It is not believed that it is publicly known to apply this theorem to calculating the eccentricity of an electric motor. The proof of this theorem is lengthy, so it is provided as an appendix at the end of the specification.

[0152] N of the electric motor w Since the windings are arranged at equal angular intervals in the circumferential direction, the representative circumferential positions (angles) of each winding are also at equal angular intervals due to rotational symmetry. In addition, the point through which the outermost circle of the rotor passes is on the representative circumferential position (angle) of each winding, so Equation (8) or Equation (9) can be applied, and the eccentricity (a ' ,a2 ' ) can be calculated.

[0153] Using equation (8) or equation (9), N w This method requires far less calculation effort than the three-point method, which calculates the amount of eccentricity for all combinations of three points selected from the points on the outermost circle of a rotor, or the numerical analysis method, which calculates the amount of eccentricity using the least squares method, etc. Therefore, it can significantly reduce memory usage.

[0154] In addition, even small servo motors that drive the main shaft of press machines have a rotor radius of 100 mm or more, which is sufficiently larger than the gap length between the stator and rotor (the maximum value of the vector sum of the eccentricity). w But, N w Equation (9) can calculate the amount of eccentricity with high accuracy even for odd numbers ≥ 3. It has also been confirmed that the values ​​calculated using equations (8) and (9) are nearly identical to those calculated using the least squares method.

[0155] This method calculates the eccentricity by taking the arithmetic mean of the coordinates of the points on the outermost circle at the representative circumferential positions (angles) of all the windings at equally spaced angles and then doubling the result. This is called the "arithmetic mean doubling method" in this specification.

[0156] In order to calculate the eccentricity with high accuracy, the N w It is advisable to consider all of the individual windings, but it is not necessarily necessary to consider all of the windings.

[0157] In the case of the "three-point method," the amount of eccentricity can be calculated if there are at least three points. In addition, the arithmetic mean doubling method only requires that all windings at equally spaced angles be considered, and the number of windings N w If is even, for example, N w = 6, if the first, second, third, fourth, fifth, and sixth windings are arranged in this order at equal intervals of 60° around the circumference, then only the first, third, and fifth windings may be considered because they are arranged at equal intervals.

[0158] If the number of windings used in calculating the eccentricity is limited to a few windings, the amount of memory used can be reduced.

[0159] The case where the number of windings is 2 will be explained using FIG. 9(B). The origin O is the center point of the stator, or the center point when there is no eccentricity of the rotor. The air gap length L g1 ' , L g2 'Let P1 and P2 be the points on the rotor's outermost circle, calculated by the formula above. When the number of windings is two, the position of the rotor's outermost circle can be determined by considering the radius r of the rotor's outermost circle in addition to the air-gap length. However, two rotor outermost circles with the same radius r are obtained, as shown by the solid and dashed circles in Figure 9(B). In other words, two centers of the outermost circle are obtained, and the eccentricity cannot be determined as a single point. If the centers of the rotor's outermost circle are C1 and C2, respectively, the two circles are symmetrical with respect to the line segment P1P2. Therefore, triangles OP1C1 and OP1C2 are clearly congruent, meaning that the lengths of line segments OC1 and OC2 are equal. The lengths of line segments OC1 and OC2 are the distances from the origin O to the center point of the rotor's outermost circle, i.e., the vector sum of the eccentricity. Therefore, the vector sum of the eccentricity can be determined as a single value. Knowing the vector sum of the eccentricity allows the minimum air-gap length to be calculated. One of the objects of the present invention is to detect contact between the stator and rotor, so if the minimum air gap length is known, there is no practical problem.

[0160] From the above, the air gap length L between the stator and rotor near the winding at any eccentricity is gk ' , and any eccentricity (a1 ' ,a2 ' ) can be calculated.

[0161] [Method for calculating eccentricity of rotating electric machines] FIG. 10 is a flowchart showing an embodiment of a method for calculating the eccentricity of a rotary electric machine, and the eccentricity calculation device is executed by the device for calculating the eccentricity of a rotary electric machine shown in FIG. 1 or FIG.

[0162] 10, an eccentricity calculation mode is selected in step S1. The eccentricity calculation mode is selected in the mode selection unit 212 in Fig. 1. The selection can be made, for example, by the operator operating a touch panel (not shown) provided in the mode selection unit 212.

[0163] When the eccentricity calculation mode is selected, in step S2, the upper control device 210 sends a switching signal Mdq to the dc-qc axis current command calculation unit 216 so that the dc-qc axis current command is for the eccentricity calculation mode. * Output.

[0164] In step S3, the dc-qc axis current command calculation unit 216 calculates i dc * =0, i qc * =0 to stop the electric motor 110.

[0165] In step S4, the host controller 210 issues a brake control command Bc to the brake control unit 172 to open or close the brake 170. * to open or close the brake 170.

[0166] In step S5, the dc-qc axis current command calculation unit 216 calculates the dc-qc axis current command i dc * and the qc-axis current command i qc * (See Figure 4(A)).

[0167] i dc * , i qc * As in the normal operation mode of FIG. 4(B), the dc-axis current command idc* may be commanded to be, for example, 0, or may be commanded to be the maximum torque, maximum efficiency, and power factor=1. qc * is calculated based on the torque command T*, for example, from the torque equation of the electric motor 110, and is commanded. dc * By setting the command to 0, the value of the current vector can be minimized, which reduces the effect of voltage drop due to resistance when calculating the amount of eccentricity. Also, if the command is set to correspond to the various operating conditions at the customer's motor sales site, the amount of eccentricity can be calculated without stopping the customer's operation.

[0168] In step S6, the processor 370 (FIG. 5) of the eccentricity calculation device calculates the dc-axis voltage v of the k-th winding after the command in step S5. dck ' , qc-axis voltage v qck ' , dc axis current i dck ' , qc axis current i qck ' (k=1, 2, …, N w ) and store it in memory 380.

[0169] In step S7, the processor 370 performs the calculation of equation (3), equation (4), or equation (5) based on these stored values, the motor constant (phase resistance Ra of the motor) pre-stored in the memory 380, and the calculation formula for the eccentricity amount, and stores the calculation result in the memory 380. Here, equation (3), equation (4), or equation (5) is based on the air gap length L gk ' This is the first calculation formula (approximation formula) for calculating the center point of the circle (eccentricity amount (a1 ' ,a2 ' )) is calculated by the formula (6), and the eccentricity (a1 ' ,a2 ' ) and the eccentricity (a1 ' ,a2 ' The equations (8) and (9) for calculating the amount of eccentricity are second equations for calculating the amount of eccentricity, and are part of the equations for calculating the amount of eccentricity stored in the memory 380.

[0170] The air gap length L between the stator and rotor near each winding gk ' From the dimensions of the stator, find the point where the outermost circle of the rotor passes through. Select three points from the points found to find the circumscribed circle, and calculate the center point using equation (6) to find the eccentricity (a1 ' ,a2 ' ) is calculated using the "three-point method," or the least squares method of equation (7) is used to find the circumscribed circle, and the center point is calculated to find the eccentricity (a1 ' ,a2 ' ) or the new theorem of equation (8) or equation (9) to calculate the eccentricity (a1 ' ,a2' ) by using either the "arithmetic mean double method" or the "arithmetic mean double method" to calculate the eccentricity (a1 ' ,a2 ' ) is calculated.

[0171] The calculated eccentricity (a1 ' ,a2 ' ), void length L gk ' One or more of the above is stored in the memory 380, and the eccentricity amount (a ' ,a2 ' ), void length L gk ' and outputting at least one of the above to the eccentricity amount display device 350 and the abnormality alarm device 360, and then the eccentricity amount calculation mode is terminated.

[0172] To verify the validity of the above, the eccentricity calculation mode was verified by magnetic field analysis based on the flowchart in FIG.

[0173] The motor 110 is a 6-pole, 9-slot, three-phase permanent magnet synchronous motor. Fig. 11 shows the mechanical dimensions of the motor 110. Fig. 12 shows the coil arrangement and wiring diagram. The symbol next to the coil symbol indicates that when a positive symbol is used, the current flows toward the page when a positive current is flowing, and when a negative current is used, the current flows away from the page. When a negative symbol is used, the current flows away from the page when a positive current is flowing, and when a negative current is flowing, the current flows away from the page. This indicates that the current flows in the direction toward the center of the stator. The stator winding has one winding wound around the teeth in a concentrated manner, with three windings of the same phase connected in series. The magnet is also an arc-shaped surface magnet type.

[0174] In this verification, the eccentricity calculation mode opens the brake 170 to keep the rotation speed constant, and the dc-axis current command i dc * , qc axis current command i qc * is constant, the dc axis current i of the kth winding (k=1, 2, 3) dck , qc axis current i qckThis is the case where the average current is constant in a steady state. However, it does not necessarily have to be a steady state, and a transient state where the rotation speed and current are not constant is also acceptable. In the case of a transient state, the amount of eccentricity can be calculated using the voltage and current of each winding at the same time.

[0175] First, as pre-analysis data for calculating the amount of eccentricity, the air gap length L is calculated in the direction of the representative circumferential position (angle) of the first winding (here, the direction of 130°, which is the coil gravity center position (angle) of the first winding, but is not limited to this. Due to rotational symmetry, the representative circumferential position (angle) of the second winding is 250°, and the representative circumferential position (angle) of the third winding is 10°). g1 = 1.9 mm, 1.6 mm, 1.3 mm, 1.0 mm (no eccentricity), 0.7 mm, 0.4 mm, 0.1 mm, and the motor 110 is operated. dc1 , v qc1 , i dc1 , i qc1 , v dc1 -R a1 ×i dc1 and v qc1 -R a1 ×i qc1 The average values ​​of v in [Table 1] are shown. qc1 -R a1 ×i qc1 and the gap length L g1 The relationship is shown in Figure 13.

[0176] [Table 1]

[0177] In this embodiment, the phase resistance R of each winding, which is a motor constant, ak is R ak =5Ω(k=1,2,3).

[0178] As shown in FIG. 13, in the first embodiment, v qc1 -R a1 ×i qc1 And, L g1 It can be seen that the relationship can be approximated by a straight line. From Figure 13, the following approximate formula can be obtained:

[0179]

number

[0180] In addition, the air gap length L of the other windings other than the first winding gk As mentioned above, if an appropriate map is used, once a map is found for only one winding, the same map can be used for the other windings, so the above equation is the same as the approximate equation for the first winding.

[0181] Also, v dc1 -R a1 ×i dc1 and the gap length L g1 Maps of (v dcl -R a1 ×i dcl , v qcl -R a1 ×i qcl ) and the gap length L g1 From the map, qc1 -R a1 ×i qc1 and the gap length L g1 Since the map of is more appropriate, the latter is adopted in the first embodiment.

[0182] Next, as an arbitrary eccentricity amount, (a1 ' ,a2 ' ) = (0.0mm,-0.5mm), (-0.3mm,-0.4mm), (0.6mm,-0.7mm), (0.9mm,0.2mm), (0.0mm,0.0mm), the same operating conditions (rotation speed, i dck , i qck When the motor is operated with the same voltage, the v of the kth winding qck ' -R ak ×i qck ' The average values ​​are shown in Table 2.

[0183] [Table 2]

[0184] [Table 2] and v in Eq. (10) qcl -R al ×i qcl To, v qck ' -R ak ×i qck ' Substituting (k=1, 2, 3), the representative circumferential position (angle) of each winding is θ rmck The gap length L gk ' The results are shown in Table 3.

[0185] [Table 3]

[0186] [Table 3] and the radius of the stator (= inner diameter / 2) = 60 mm, the point (x k ,y k The results are shown in Table 4.

[0187] [Table 4]

[0188] Then, a circumscribed circle is found from the three points found, and the center point is calculated using equation (6) to determine the eccentricity (a1 ' ,a2 ' ) is calculated using the "three-point method," or the least squares method of equation (7) is used to find the circumscribed circle, and the center point is calculated to find the eccentricity (a1 ' ,a2 ' ) or the new theorem of equation (9) to find the eccentricity (a1 ' ,a2 ' The results of calculating the eccentricity using either the "arithmetic mean doubling method" or the "arithmetic mean doubling method" are shown in [Table 5].

[0189] [Table 5]

[0190] From [Table 5], it can be said that the eccentricity calculated by either method and the set eccentricity amount match well.

[0191] The abnormality alarm device 360 ​​in FIG. 1 not only inputs the calculated eccentricity and compares it with the threshold eccentricity that is the criterion for determining abnormality, but also calculates the gap length L gk ' The value may be input and compared with the threshold gap length that is the criterion for determining abnormality, and an alarm may be issued.

[0192] After the eccentricity calculation mode is completed, the mode selection unit 212 selects the normal operation mode, and the electric motor 110 is operated normally.

[0193] FIG. 14 is a flowchart showing a specific processing procedure performed by the control device for a rotary electric machine when the normal operation mode is selected.

[0194] In FIG. 14, in step S11, the normal operation mode is selected by the mode selection unit 212 (FIG. 1). When the normal operation mode is selected, in step S12, the host control device 210 issues a brake control command Bc to the brake control unit 172 to open the brake 170. * to open the brake 170.

[0195] In step S13, the host controller 210 issues a speed command N * and outputs a switching signal Mdq to the dc-qc axis current command calculation unit 216 so that the dc-qc axis current command is for the normal operation mode. * Output.

[0196] In step S14, the dc-qc axis current command calculation unit 216 calculates the torque command T * According to the DC axis current command i dc * , qc axis current command i qc * to operate the electric motor 110.

[0197] In summary, the apparatus for calculating the eccentricity of a rotary electric machine according to the present invention has the following advantages over known techniques, making it possible to obtain an apparatus and method for calculating the eccentricity that are superior to known techniques.

[0198] 1. The control device (vector control system) that drives the electric motor can calculate the amount of eccentricity with high precision.

[0199] 2. The amount of eccentricity can be calculated using the control device (vector control system) that drives the motor, making it possible for the motor's sales destination to calculate the amount of eccentricity.

[0200] In addition, there are the following differences from the prior art.

[0201] The methods of Patent Documents 1 and 2 can be said to be methods of finding the amount of eccentricity by directly associating the amount of eccentricity with three-phase AC voltage, while the method of Patent Document 3 can be said to be a method of associating the waveform of a current that has been converted from three phases to two phases with an abnormality (such as eccentricity).

[0202] On the other hand, in the present invention, the control device detects the change in the eccentricity. dck -R ak ×i dck , v qck -R ak ×i qck , or (v dck -R ak ×i dck ,v qck -R ak ×i qck ) for the vector sum of the gap length L gk The method is to calculate the eccentricity by finding the point through which the outermost circumference of the rotor passes from the air gap length and then finding the center point of the outermost circumference.

[0203] First, to calculate the eccentricity, v dck or v qck It is not a map of the relationship between the resistance and the gap length, but a map of the voltage drop due to the phase resistance. dck -R ak ×i dck , v qck -R ak ×i qck, or (v dck -R ak ×i dck , v qck -R ak ×i qck Since the map shows the relationship between the vector sum of (a) and (b) and the air gap length, the same map can be used for all of the multiple polyphase windings. In the cases described in Patent Documents 1 and 2, a map must be provided for each winding to take into account the effects of phase resistance. Furthermore, Patent Document 3 does not have any requirements for the composition of an equation for calculating the amount of eccentricity.

[0204] Second, the method differs from Patent Documents 1 and 2 in that it calculates the eccentricity using coordinate-transformed values ​​of voltage and current. The method in Patent Document 1 merely determines the relationship between the effective value of voltage or current (or the value obtained by rectifying AC current with a rectifier) ​​and the eccentricity; it does not describe or suggest anything about the relationship between the coordinate-transformed values ​​of voltage and current and the eccentricity ratio (amount of eccentricity). Embodiment 1, which describes the main content of Patent Document 1, uses a capacitor motor as an example. Since this is not a vector-controlled motor, we presume there was no motivation to perform coordinate transformation of the voltage or current. Embodiment 5 in Patent Document 1 is a derivative of Embodiment 1, and Patent Document 2 also uses a three-phase AC motor as an example. However, there is no mention of vector control here either, and only an example of an externally driven generator is shown. Therefore, it is believed that the eccentricity calculation methods in Patent Documents 1 and 2 do not involve the idea of ​​calculating the eccentricity of a vector-controlled motor (which involves transforming the voltage and current into coordinates and controlling them using the transformed state variables).

[0205] Furthermore, as can be seen from the coordinate transformation formulas of equations (1) and (2), the coordinate transformation formulas are not scalar quantity calculations such as simply multiplying the effective voltage value by a proportional factor or performing differential and integral calculations, but are vector quantity calculations that convert the instantaneous values ​​of voltage and current into vectors on two orthogonal axes according to the rotor position. This invention is the first to clarify that the approximation formulas of maps that associate the components of such vector quantities with the air gap length and eccentricity amount become linear functions or monotonically increasing functions, and we believe that this invention is novel and inventive in that it utilizes this to calculate eccentricity amount.

[0206] Coordinate transformation also has the following advantage. When a motor is driven to rotate at a constant speed and the voltage and current are in a steady state, the voltage and current become steady DC in a coordinate system synchronized with the rotation. This makes measurement and analysis much easier than with AC quantities. As mentioned earlier, the effective value of the voltage related to the magnetic flux linkage can be found by simply calculating the vector sum.

[0207] Furthermore, in the present invention, coordinate transformation calculations are performed, but the coordinate transformation program provided in the vector control device can be used, thereby reducing the amount of memory used.

[0208] Furthermore, in this invention, when calculating the amount of eccentricity after finding the gap length between the stator and rotor near a certain winding and calculating the points through which the outermost circle of the eccentric rotor passes, the inventors clarify specific methods for calculating the amount of eccentricity using the "three-point method" that applies the geometric theorem "every triangle has a circumscribing circle," the "numerical analysis method" that finds the circumscribing circle using the least squares method or the like from multiple points through which the outermost circle passes and then finds the center point, and the "arithmetic mean doubling method" that calculates the eccentricity by taking the arithmetic mean of multiple points through which the outermost circle passes at equally spaced angles and doubling the result. In particular, the inventors discovered and proved the geometric theorems (Equations (8) and (9)) used in the "arithmetic mean doubling method," and, as far as the inventors have investigated, believe that this is a new geometric theorem, and therefore is novel, and the inventors believe that this method has an inventive step because it has the advantage of requiring less calculation time than the other two methods.

[0209] Furthermore, the second formula for calculating the amount of eccentricity is a formula that calculates the amount of eccentricity from the point through which the outermost rotor circle, which is determined from the air gap length, passes. Therefore, it goes without saying that it can be used regardless of differences in motor structure (synchronous motor, induction motor, DC motor) or control system (vector control system, V / F operation, operation directly connected to an AC power source).

[0210] Thus, the present invention is completely different from Patent Documents 1 and 2 in the method used. Furthermore, Patent Document 3 uses coordinate-converted current but not coordinate-converted voltage, which differs from the present invention in that voltage is also a constituent element. Furthermore, Patent Document 3 differs from Patent Document 3 in that it can calculate the amount of eccentricity with high precision. As mentioned above, Patent Document 3 does not disclose or suggest a specific method for calculating the amount of eccentricity.

[0211] Thirdly, it is clear that the present invention differs from Patent Document 3, which estimates eccentricity by focusing on the change in the frequency component of the current detected by the control device when an abnormality (eccentricity, etc.) occurs (however, it is not possible to estimate the specific amount of eccentricity (a1, a2)), in that it does not focus on the frequency component of the current.

[0212] From the above, Patent Document 1, Patent Document 2, and Patent Document 3 are clearly different from the present invention, and even if they are combined, it is impossible to produce anything similar to the present invention, and we are convinced that the present invention would not have been easily conceived by a person skilled in the art with ordinary knowledge in this field.

[0213] <Second embodiment of device and method for calculating eccentricity of rotating electric machine> In the first embodiment of the device and method for calculating the amount of eccentricity of a rotating electric machine, the air gap length between the stator and rotor near each winding is calculated, and then the point on the outermost circle of the rotor is found from this and the dimensions of the stator to calculate the amount of eccentricity. In the second embodiment, a method for calculating the amount of eccentricity from the voltage and current of each winding when the rotor is eccentric in the horizontal direction (X-axis direction) and vertical direction (Y-axis direction) will be described.

[0214] [Calculating the orthogonal projection components in the X-axis and Y-axis directions of the voltage space vector related to the magnetic flux linkage of each winding when the rotor is eccentric in the horizontal direction (X-axis direction) and vertical direction (Y-axis direction), and creating a map of the amount of eccentricity corresponding to the composite voltage, which is the sum of these orthogonal projection components] Under certain operating conditions, the rotor of the motor is eccentric in the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction), and the dc-axis voltage v is calculated by changing the amount of eccentricity (a1, a2).dck , qc-axis voltage v qck , dc axis current i dck , and the qc axis current i qck is obtained by measurement or analysis. From these values, the voltage related to the magnetic flux linkage, v dck -R ak ×i dck , v qck -R ak ×i qck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) where v dck , v qck Not v dck -R ak ×i dck , v qck -R ak ×i qck The reason for this has been explained in the first embodiment and will be omitted here.

[0215] v dck -R ak ×i dck , v qck -R ak ×i qck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) as a space vector, the magnitude is v dck -R ak ×i dck , v qck -R ak ×i qck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) and the direction is the kth winding of the motor (k=1, 2, ..., N w ) Representative circumferential position (angle) θ rmck θ rmckThis has been explained in the first embodiment, so it will be omitted here.

[0216] Next, the orthogonal projection component of the horizontal direction (X-axis direction) of the voltage space vector of each winding is calculated as the voltage related to the magnetic flux linkage and the representative circumferential position (angle) θ rmck The sum of these voltages, the composite voltage Vsx in the X-axis direction, is calculated using the following formula:

[0217]

number

[0218]

number

[0219]

number

[0220] Similarly, the orthogonal projection component of the voltage space vector of each winding in the vertical direction (Y-axis direction) is expressed as the voltage related to the magnetic flux linkage and the representative circumferential position (angle) θ rmck The sum of these voltages, the Y-axis composite voltage Vsy, is calculated using the following formula:

[0221]

number

[0222]

number

[0223]

number

[0224] Then, a map (first map) of Vsx and the amount of eccentricity a1 in the horizontal direction (X-axis direction), and a map (second map) of Vsy and the amount of eccentricity a2 in the vertical direction (Y-axis direction) are calculated.

[0225] After the map calculation, a function of the eccentricity a1 in the horizontal direction (X-axis direction) with Vsx as a variable (i.e., the first approximation formula) and a function of the eccentricity a2 in the vertical direction (Y-axis direction) with Vsy as a variable (i.e., the second approximation formula) are obtained.

[0226]

number

[0227]

number

[0228] From the above, when the rotor is eccentric in the horizontal direction (X-axis direction) and vertical direction (Y-axis direction), the orthogonal projection components in the X-axis direction and Y-axis direction of the voltage space vector related to the magnetic flux linkage of each winding can be found, and an approximate equation can be created from a map of the amount of eccentricity corresponding to the composite voltage, which is the sum of these orthogonal projection components.

[0229] [Any eccentricity (a1 ' ,a2 ' ) calculation] Any eccentricity of the motor (a1 ' ,a2 ' ) for each winding under the same operating conditions as when the map was obtained. dck ', v qck ',i dck ',i qck ' is determined by measurement or analysis.

[0230] Next, from these values ​​and the motor constants, v dck '-R ak ×i dck ', v qck '-R ak ×iqck', or (v dck '-R ak ×i dck ', v qck '-R ak ×i qck ') to calculate the vector sum.

[0231] And, v in equation (11) dck -R ak ×i dck To, v dck '-R ak ×i dck Substituting ', or v in equation (12) qck -R ak ×i qck To, v qck '-R ak ×i qck ', or (v dck -R ak ×i dck , v qck -R ak ×i qck ) vector sum, (v dck '-R ak ×i dck ', v qck '-R ak ×i qck Substitute the vector sum of Vsx and Vsx', and then set the arbitrary eccentricity (a1 ' ,a2 ' ) is calculated, and similarly, any eccentricity amount (a1 ' ,a2 ' ) and calculate Vsy'.

[0232] In equations (17) and (18), Vsx is replaced with Vsx', Vsy is replaced with Vsy', and a1 is replaced with a1 ' Let a2 be a2 ' As a result, the eccentricity (a1 ' ,a2 ' ) is calculated.

[0233] The flowchart showing the second embodiment of the method for calculating the amount of eccentricity of a rotary electric machine is the same as that shown in Fig. 10. The only difference from the first embodiment is the method for calculating the amount of eccentricity.

[0234] The calculation formula for the eccentricity amount in step S7 is the gap length L gk Instead of the first equation for calculating ', the first equation is one that finds the orthogonal projection components in the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction) of the voltage space vector of each winding and calculates their sums, the X-axis resultant voltage Vsx and the Y-axis resultant voltage Vsy, and instead of the second equation for calculating the eccentricity from the air gap length of the first embodiment, the second equation is one that calculates a function of the horizontal direction (X-axis direction) eccentricity a1 using Vsx as a variable (i.e., the first approximation equation) and a function of the vertical direction (Y-axis direction) eccentricity a2 using Vsy as a variable (i.e., the second approximation equation).

[0235] In order to verify the validity of the above, the eccentricity calculation mode was verified by magnetic field analysis based on the flowchart of Fig. 10. The motor and operating conditions were the same as those in the first embodiment.

[0236] First, as pre-analysis data for calculating the amount of eccentricity, Vsx and Vsy are obtained when the electric motor 110 is operated with eccentricity set in advance in the horizontal direction (X-axis direction) and vertical direction (Y-axis direction).

[0237] Here, the graph of Vsx and Vsy values ​​and eccentricity in equation (12) and the graph of Vsy value and eccentricity in equation (15) were found to be the most appropriate (the graphs of Vsx and Vsy and eccentricity were closest to a straight line) than the graphs of Vsx and Vsy values ​​and eccentricity in equations (11) to (16) other than equations (12) and (15), so the latter was adopted in this embodiment.

[0238] Table 6 shows the results of Vsx (equation (12)) when eccentricity is previously set in the horizontal direction (X-axis direction), and Table 7 shows the results of Vsy (equation (15)) when eccentricity is previously set in the vertical direction (Y-axis direction).

[0239] [Table 6]

[0240] [Table 7]

[0241] Fig. 15(A) shows a graph of horizontal eccentricity a1 versus Vsx in Table 6. Fig. 15(B) shows a graph of vertical eccentricity a2 versus Vsy in Table 7.

[0242] 15, it can be seen that in the second embodiment, the relationship between Vsx and the X-axis eccentricity a1 and the relationship between Vsy and the Y-axis eccentricity a2 can be approximated by a straight line. From FIG. 15, the following approximate formula can be obtained.

[0243]

number

[0244]

number

[0245] Next, as an arbitrary eccentricity amount, (a1 ' ,a2 ' ) = (0.0mm,-0.5mm), (-0.3mm,-0.4mm), (0.6mm,-0.7mm), (0.9mm,0.2mm), (0.0mm,0.0mm), the same operating conditions (rotation speed, i dck , i qck When the motor is operated with the same voltage, the v qck '-R ak ×i qck The mean value of ' is the same as [Table 2].

[0246] v in equation (12) qck -R ak ×i qck , vqck '-R ak ×i qck ', Vsx is Vsx', calculate Vsx' of any eccentricity, and use v in equation (15) qck -R ak ×i qck , v qck '-R ak ×i qck The result of calculating the amount of eccentricity by applying this to equations (20) and (21) is shown in Table 8.

[0247] [Table 8]

[0248] From [Table 8], it can be said that the calculated eccentricity and the set eccentricity are in good agreement.

[0249] The second embodiment has the advantage that, compared to the first embodiment, more measurement or analysis data is required to prepare in advance for the map of voltage and eccentricity, but dimensional information of the rotor is not required.

[0250] Furthermore, in the second embodiment, the orthogonal projection components of the voltage space vector of each winding in the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction) are calculated, and the sums of these components, that is, the X-axis composite voltage Vsx and the Y-axis composite voltage Vsy, are associated with the eccentricity amounts of the two orthogonal axes. Therefore, even if each winding is not located on the horizontal (X-axis) and vertical (Y-axis) axes, a map in the two orthogonal axis directions can be calculated.

[0251] Furthermore, the approximate equations of equations (19) and (20) are simple equations of a line passing through the origin. This is because they are found from the relationship between the amount of eccentricity and the resultant voltage, which is the sum of the components of the voltage space vector of the windings arranged at equal intervals around the circumference, orthogonally projected in the X-axis and Y-axis directions.

[0252] Number of windings N w If is an even number, we can obtain the equation of the line passing through the origin by considering only the windings that are evenly spaced. For example, Nw When N = 6, if the first, second, third, fourth, fifth, and sixth windings are arranged in this order at 60° intervals in the circumferential direction, the first, third, and fifth windings are arranged at equal intervals, so if you consider only these to find Vsx and Vsy and find the relationship with the amount of eccentricity, you get an equation for a straight line passing through the origin, which can be used to calculate the amount of eccentricity with high precision. w When is an even number, the number of windings to be considered can be reduced to calculate the amount of eccentricity, which has the advantage of reducing the amount of memory used.

[0253] However, the number of windings N w When is an odd number, it is not possible to skip a winding as in the even number case, and it is necessary to take all windings into consideration in order to obtain such a simple equation, and it is therefore necessary to note that the amount of eccentricity cannot be calculated accurately. Furthermore, the abnormality warning device 360 ​​in FIG. 1 may not only input the calculated eccentricity amount and compare it with the threshold eccentricity amount that serves as the abnormality judgment criterion, but may also input the values ​​of Vsx and Vsy and compare them with the thresholds Vsx and Vsy that serve as the abnormality judgment criterion to issue an alarm.

[0254] <Third embodiment of device and method for calculating eccentricity of rotating electric machine> In the first and second embodiments, in the eccentricity calculation mode, the brake 170 is opened, the rotation speed is constant, and the dc-axis current command i dc * , qc axis current command i qc * is constant, the dc axis current i of the kth winding dck , qc axis current i qck (k=1, 2, …, N w ) is the DC axis voltage V when the average current is constant dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck (k=1, 2, …, N w ) and calculated the eccentricity.

[0255] In the third embodiment, in the eccentricity calculation mode, the brake 170 is closed to lock the rotor and the dc-axis current command i dc * , qc axis current command i qc * is controlled to be a steady AC current, and the dc axis current i dck , qc axis current i qck DC axis voltage V when is a steady AC current dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck The amount of eccentricity is calculated from the above.

[0256] dc axis current command i dc * , qc axis current command i qc * is set as a steady AC current because the rotor is stationary and the dc axis current command i dc * , qc axis current command i qc * If a steady-state DC current is commanded as i, the voltage related to the magnetic flux linkage of the motor windings becomes 0, no voltage difference occurs between the windings, and the amount of eccentricity cannot be calculated. dc * , qc axis current command i qc * is not necessarily a steady AC current, but may be a current command that generates a voltage related to the magnetic flux linkage of the motor windings, for example, a step-like or ramp-like current command. This is because the step-like dc-axis current command i dc * or qc-axis current command i qc * Theoretically, the DC-axis voltage command v contains frequency components ranging from 0 to infinity. dc * This is because the motor current command contains such frequency components, and a voltage related to the magnetic flux linkage of the motor winding can be obtained even in a stationary state. Step-type and ramp-type current commands are easy to implement.

[0257] In the first and second embodiments, the stator winding of the electric motor is a 6-pole, 9-slot, three-phase permanent magnet synchronous motor in which one winding is wound around one tooth in a concentrated manner.

[0258] The motor of the third embodiment is a three-phase squirrel-cage induction motor with a stator winding of 12 poles and 45 slots distributed winding and a rotor with 90 conductor bars.

[0259] Fig. 16 is a cross-sectional view of the main part of the motor and a diagram showing the machine dimensions. Fig. 17 is a cross-sectional view of the main part of the motor and a diagram showing the coil arrangement and wiring, and shows the entire coil arrangement for only the U phase. For the V and W phases, only the starting and ending ends of the windings are shown. The stator winding consists of three windings of the same phase connected in series.

[0260] The eccentricity is calculated using the air gap length L between the stator and rotor near the k-th winding in the first embodiment. gk The calculation is performed by using a map of voltages related to the magnetic flux linkage when the magnetic flux linkage is changed.

[0261] First, as pre-analysis data for calculating the amount of eccentricity, the air gap length L is calculated in the direction of the representative circumferential position (angle) of the first winding (here, the direction of 96°, which is the coil gravity center position (angle) of the first winding, but is not limited to this. Due to rotational symmetry, the representative position (angle) of the second winding is 216°, and the representative position (angle) of the third winding is 336°). g1 = 1.9 mm, 1.6 mm, 1.3 mm, 1.0 mm (no eccentricity), 0.7 mm, 0.4 mm, 0.1 mm, and the motor 110 is operated. dc1 , v qc1 , i dc1 , i qc1 , v dc1 -R a1 ×i dc1 , and v qc1 -R a1 ×i qc1 The effective values ​​of are shown in Table 9. dc1 -R a1 ×i dc1 and the gap length L g1 The relationship between these two is shown in Figure 18.

[0262] In this embodiment, the phase resistance R of each winding, which is a motor constant, ak is R ak =5Ω(k=1,2,3).

[0263] [Table 9]

[0264] As shown in FIG. 18, in the third embodiment, v dc1 -R a1 ×i dc1 And, L g1 Although the relationship is not linear, it is monotonically decreasing and can be approximated by a quadratic curve. From Figure 18, the following approximate formula can be obtained:

[0265]

number

[0266] In addition, the air gap length L of the other windings other than the first winding gk As mentioned above, if an appropriate map is used, once a map is found for only one winding, the same map can be used for the other windings, so the above equation is the same as the approximate equation for the first winding.

[0267] Also, v qc1 -R a1 ×i qc1 and the gap length L g1 Maps of (v dcl -R a1 ×i dcl , v qcl -R×i qcl ) and the gap length L g1 From the map, dc1 -R a1 ×i dc1 and the gap length L g1 Since the map of is more appropriate, the latter is adopted in the third embodiment.

[0268] Next, as an arbitrary eccentricity amount, (a1 ' ,a2' ) = (0.0mm,-0.5mm), (-0.3mm,-0.4mm), (0.6mm,-0.7mm), (0.9mm,0.2mm), (0.0mm,0.0mm), the same operating conditions as when the measurement was performed in advance (rotation speed (0 because it is stationary), i dck , i qck When the motor is operated with the same voltage, the v of the kth winding dck '-R ak ×i dck The effective values ​​of ' are shown in [Table 10].

[0269] [Table 10]

[0270] [Table 10] and v in Eq. (21) dcl -R al ×i dcl To, v dck '-R ak ×i dck ' (k=1, 2, 3) and assign the representative circumferential position (angle) θ of each winding rmck The gap length L gk The results are shown in Table 11.

[0271] [Table 11]

[0272] [Table 11] and the radius of the stator (= inner diameter / 2) = 60 mm, the point (x k ,y k The results are shown in Table 12.

[0273] [Table 12]

[0274] Then, a circumscribed circle is found from the three points found, and the center point is calculated using equation (6) to determine the eccentricity (a1 ' ,a2 ') is calculated using the "three-point method," or the least squares method of equation (7) is used to find the circumscribed circle, and the center point is calculated to find the eccentricity (a1 ' ,a2 ' ) or the new theorem of Eq. (9) to calculate the eccentricity (a1 ' ,a2 ' The results of calculating the eccentricity using either the "arithmetic mean doubling method" or the "arithmetic mean doubling method" are shown in [Table 13].

[0275] [Table 13]

[0276] From [Table 13], it can be said that the eccentricity calculated by either method and the set eccentricity amount are in good agreement.

[0277] Compared with the results of the first and second embodiments, the difference between the calculated value and the set value of the eccentricity is large because, as mentioned above, dc1 -R a1 ×i dc1 And, L g1 This is because the above relational expression is not the most appropriate linear relation map, but a monotonically decreasing quadratic function map, and so the error increases as the distance to the rotor decreases due to eccentricity.

[0278] However, the absolute value of the difference between the calculated value and the set value of the eccentricity is still less than 0.1 mm, which is considered to be sufficient accuracy for detecting contact between the rotor and the stator, which is the object of the present invention.

[0279] In the verification of this embodiment, as shown in [Table 9], qc1 = 0, and the dc axis current i dc1 This is done to improve the accuracy of calculating the amount of eccentricity.

[0280] In the present invention, the voltage related to the magnetic flux linkage corresponding to the air gap length is v dck -R ak ×i dck , v qck -R ak ×iqck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) is shown as an example of the vector sum, and a map of voltage and air gap length related to the more appropriate magnetic flux linkage is used, but other unused maps also contain information on the amount of eccentricity, although with lower accuracy. Therefore, if the voltage related to the magnetic flux linkage of the unused maps is intentionally controlled to be smaller, and the distribution of voltage related to the magnetic flux linkage of the used maps is increased accordingly, the information on the amount of eccentricity will be consolidated and accuracy will increase. This method of energizing only specific axes is particularly effective when the motor is stationary, but it goes without saying that it is also effective when the motor is rotating.

[0281] Furthermore, this example shows that the amount of eccentricity can be calculated even when the rotor of the motor is stationary, which brings about the special effect of being able to calculate the amount of eccentricity even in situations where it is not desirable to move the main shaft of a mechanical device, such as a crankshaft.

[0282] <Fourth embodiment of device and method for calculating eccentricity of rotating electric machine> The U-phase, V-phase, and W-phase windings of the electric motor 110 of the first, second, and third embodiments each include a plurality of N w The windings are connected in series or in parallel, and the motor 110 appears to be configured as a motor 110 with a single set of multi-phase windings. However, in the fourth embodiment, an apparatus and method for calculating eccentricity for a motor with multiple windings is shown, in which all of the multiple windings or some adjacent windings are connected in series or in parallel, and multiple U-phase, V-phase, and W-phase windings are pulled out to the outside of the motor.

[0283] 19 is a diagram showing the overall configuration of a rotary electric machine control device including an eccentricity calculation device for a rotary electric machine according to a fourth embodiment of the present invention, and a mechanical device equipped with a rotary electric machine. Note that parts common to the first embodiment shown in FIG. 1 are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0284] [Electric motor] FIG. 20 is a cross-sectional view of a main part of an electric motor applied to a control device for a rotary electric machine according to the fourth embodiment.

[0285] The electric motor 110-1 shown in Fig. 20 is a polyphase electric motor. In Fig. 20, a general three-phase (U-phase, V-phase, W-phase) electric motor will be described. Furthermore, although the electric motor 110-1 will be described as a synchronous electric motor as an example, it may be any polyphase AC electric motor (not only a synchronous electric motor but also an induction electric motor).

[0286] As with the electric motor 110 with one winding in the first embodiment, the electric motor 110-1 has a plurality of N windings for U-phase, V-phase, and W-phase. w There are N windings, w The windings of each phase are mutually separated by 2π / N w The difference from the electric motor 110 of the first embodiment is that these N w All of the U-phase, V-phase, and W-phase windings, or N of the U-phase, V-phase, and W-phase windings w The windings are connected in series or in parallel, and multiple U-phase, V-phase, and W-phase windings are drawn out to the outside of the motor.

[0287] The electric motor 110-1 in the fourth embodiment has a plurality of N w All of the U, V, and W phases are drawn out to the outside of the motor.

[0288] The rotor 110b of the electric motor 110-1 is similar to that of the electric motor 110 of the first embodiment shown in FIG. 2, and therefore a description thereof will be omitted.

[0289] FIG. 21 shows the N of the motors shown in FIG. w Set of windings for each phase U k , V k , W k (k=1, 2, …, N w ) is a connection diagram showing an example of the connection.

[0290] The terminal box of the motor 110-1 has 3 × N w A terminal block is provided so that the terminal voltage of each winding can be measured, and 3 × N wAlthough current sensors capable of measuring the winding current are provided, these are not necessarily required in this embodiment, as will be described later.

[0291] [Control device for a rotating electric machine according to the fourth embodiment] 19, the control device for a rotary electric machine of the fourth embodiment includes an eccentricity calculation device for a rotary electric machine, as in the first embodiment. Also, as in the first embodiment, the electric motor 110-1 is provided with a drive shaft 112 on the side of the rotor that connects to the mechanical device (load side), and the drive shaft 112 is connected to the servo press machine 100, which is the mechanical device.

[0292] The control device for the rotary electric machine includes current control devices (220-1 to 220-N) that control multiple sets of three-phase winding currents of the electric motor 110-1. w ) are provided independently for each of the multiple sets of three-phase windings. w ) current control device (k-th winding current control device 220-k) will be described.

[0293] The three-phase AC voltage command (v ukc * , v vkc * , v wkc * ) is output to PWM conversion unit 270, where it is PWM converted and applied to servo amplifier 260. Three-phase AC power from three-phase AC power supply 240 is converted to DC power by converter 250, and the DC power is applied to the other input of servo amplifier 260. Servo amplifier 260 is a device that converts DC power to three-phase AC power, and is a well-known inverter. Servo amplifier 260 converts the DC power to three-phase AC power in accordance with the PWM-converted three-phase AC voltage command, and applies the converted three-phase AC power to the k-th winding to drive motor 110-1. The current control units of the current control devices for the other windings are controlled in the same manner.

[0294] As in the first embodiment, the control device for the electric motor 110-1 of this example has a normal operation mode for operating the electric motor 110-1 normally and an eccentricity calculation mode, and the mode selection unit 212 outputs a mode command M indicating the normal operation mode or the eccentricity calculation mode in response to a selection instruction from an operator. * is output to the upper control device 210. The configuration of the upper control device 210 is the same as that in the first embodiment.

[0295] Next, we will briefly explain the speed control and current control (vector control) system for a polyphase motor with multiple windings.

[0296] A speed command N preset from the upper control device 210 * is output to the positive input of the adder. The speed N calculated by the speed calculation unit 214 is added to the negative input of the adder, and the adder outputs the speed command N * and the deviation between the speed N (N * -N) and calculate the deviation (N * -N) to the speed control section 213. The speed control section 213 outputs the deviation (N * -N) according to the torque command T * The torque command T* is input to the dc-qc axes current command calculation unit 216. The dc-qc axes current command calculation unit 216 is the same as that in the first embodiment.

[0297] The dc-qc axis current command i output from the dc-qc axis current command calculation unit 216 dc * , qc axis current command i qc * current control devices 220-1 to 220-N for each winding w The dc axis current command i dc * , qc axis current command i qc * is added to the positive input of each adder. The dc-axis current i of the k-th winding is input to the negative input of each adder from the coordinate conversion unit 236. dck , qc axis current i qck The coordinate converter 236 is a multiphase / dc-qc converter, and converts the three-phase AC current (iuk , i vk , i wk ) and the position θ obtained by the motor position sensor 116 re Using the dc axial current i dck , qc axis current i qck As mentioned above, the position θ re Alternatively, position sensorless control may be used, and values ​​estimated and calculated from voltage and current information may be used.

[0298] dc axis current command i dc * and dc axial current i dck The adder that inputs the dc axis current command i dc * and dc axial current i dck deviation from (i dc * -i dck ) and calculate the deviation (i dc * -i dck ) to the dc-axis current control unit 232, and the qc-axis current command i qc * and qc axis current i qck The adder that inputs the qc-axis current command i qc * and qc axis current i qck deviation from (i qc * -i qck ) and calculate the deviation (i qc * -i qck ) is output to the qc-axis current control unit 234.

[0299] The dc-axis current control unit 232 calculates the input deviation (i dc * -i dck ) based on the DC axis voltage command v of the kth winding dck * The qc-axis current control unit 234 outputs the input deviation (i qc * -i qck ) based on the qc-axis voltage command v of the kth winding qck * Output.

[0300] The dc-axis current control section 232 and the qc-axis current control section 234 are configured by connecting, for example, a proportional controller (P control) and an integral controller (I control) in parallel, but the present invention is not limited to this configuration because the main purpose of the present invention is to calculate the amount of eccentricity. A differential controller (D control) may also be added in parallel to configure a so-called PID control. dc * Nii dck follows, and i qc * Nii qck Any controller having a configuration for controlling the speed so that the speed follows the speed may be used.

[0301] DC axis voltage command V dck * , qc-axis voltage command v qck * is applied to the coordinate conversion unit 238. The coordinate conversion unit 238 is a dc-qc / multiphase conversion unit, and the dc-axis voltage command v dck * , qc-axis voltage command v qck * and the position θ obtained from the motor position sensor 116. re Using the three-phase AC voltage command v ukc * , v vkc * , v wkc * As mentioned above, the position θ re The k-th winding three-phase AC voltage command v may be calculated based on voltage and current information, and the motor position sensor 116 is not necessarily required. ukc * , v vkc * , v wkc * As described above, the signal is PWM converted by the PWM converter 270 and then output to the servo amplifier 260, where it is amplified and output to the k-th winding of the electric motor 110-1. As a result, the electric motor 110-1 is current-controlled (vector-controlled). The other windings are also vector-controlled in the same manner.

[0302] The above current control is essentially the same for polyphase AC with three or more phases, as long as the polyphase AC current is subjected to coordinate transformation synchronized with the rotor to generate a two-dimensional current vector, which is then controlled, and it goes without saying that it is not limited to three phases, and is therefore not limited to three phases.

[0303] In the first embodiment, the 3×N w In this embodiment, a measurement unit is provided to measure the terminal voltages of the k-th winding. As will be described later, the DC-axis voltage command v dck * , qc-axis voltage command v qck * (k=1, 2, …, N w ) is used to calculate the amount of eccentricity, so it is not necessary to provide a voltage measurement unit. w In this embodiment, the current sensors for measuring the winding currents are the current control devices 220-1 to 220-N. w The current sensor 280 can be used. dck The measured values ​​of the qc-axis current i qck When harmonics are superimposed on the measured value of , the dc-axis current command value i is used instead of the dc-axis current measurement value to reduce the influence of harmonics. dc * is used, and the qc-axis current command value i is used instead of the qc-axis current measurement value. qc * may also be used.

[0304] [Hardware Configuration of the Eccentricity Calculation Device for a Rotating Electric Machine of the Fourth Embodiment] The hardware configuration of the device for calculating eccentricity of a rotating electric machine according to the fourth embodiment can be the same as that of the first embodiment shown in the block diagram of Fig. 5. This device for calculating eccentricity is incorporated into a control device for a rotating electric machine as shown in Fig. 19.

[0305] The processor 370 and the input / output interface 390 shown in FIG. 5 are the same as those in the first embodiment, and therefore will not be described here.

[0306] The memory 380 also stores the motor constants and eccentricity calculation formulas for the motor 110-1. The constants and eccentricity calculation formulas for the motor 110-1 are the same as the eccentricity calculation formulas shown in the first or second embodiment. In the fourth embodiment, the dc-axis voltage v of the k-th winding used in the calculation method of the first or second embodiment is calculated. dck , qc-axis voltage v qck (k=1, 2, …, N w ) is the DC-axis voltage command v of the kth winding. dck * , qc-axis voltage command v qck * (k=1, 2, …, N w ), the eccentricity can be calculated in the same way.

[0307] Furthermore, the memory 380 stores various command data (in this example, the DC axis voltage command v of the k-th winding) during the current control of the motor. dck * , qc-axis voltage command v qck * ), and measurement data (dc axis current i dck , qc axis current i qck ) and the air gap length L of each winding calculated from the motor constants and measurement data. gk (k=1, 2, …, N w ), the X-axis resultant voltage Vsx, which is the sum of the components of the voltage space vectors related to the magnetic flux linkage of each winding projected orthogonally in the X-axis direction, and the Y-axis resultant voltage Vsy, which is the sum of the components of the voltage space vectors related to the magnetic flux linkage of each winding projected orthogonally in the Y-axis direction, and further functions as a memory device for storing the amount of eccentricity when it is calculated.

[0308] As in the first embodiment, the host control device 210 can also be configured as a computer. In this case, the host control device 210 and the eccentricity calculation device 300 may be configured as the same computer, or may be configured as separate computers. The eccentricity display device 350 and the abnormality warning device 360 ​​are the same as in the first embodiment, so their explanation will be omitted.

[0309] In the first to third embodiments, it is necessary to provide a voltage / current measuring unit in the control device, and in Patent Documents 1 and 2, a dedicated voltage measuring device is also required. However, in the fourth embodiment, the DC-axis voltage command v dck * , qc-axis voltage command v qck * Therefore, it is not necessary to provide a terminal for voltage measurement in the electric motor 110-1 or to provide a voltage measurement unit in the control device of the electric motor 110-1. w Therefore, there is a special effect that the amount of eccentricity can be calculated using a normal control device that controls a motor with multiple windings.

[0310] Furthermore, in the first embodiment, it was necessary to calculate the dc-qc axis voltage and current of each winding separately from the dc-qc axis voltage and current used in motor control, but in the fourth embodiment, the dc-qc axis voltage and current values ​​used in motor control can be used as they are, thereby reducing the calculation load.

[0311] <Fifth embodiment of device and method for calculating eccentricity of rotary electric machine> Fig. 22 is a diagram showing the overall configuration of a rotary electric machine control device including an eccentricity calculation device for a rotary electric machine according to a fifth embodiment of the present invention, and a mechanical device equipped with a rotary electric machine. Note that parts common to the first and fourth embodiments shown in Figs. 1 and 19 are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0312] The first to fourth embodiments are methods for calculating the eccentricity of a motor during operation using a current control device. In the fifth embodiment, the motor is operated as a generator by another motor for external driving, and the DC axis voltage v of the motor 110-1 is calculated. dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck (k=1, 2, …, N w ) and calculates the eccentricity.

[0313] [Electric motor] In FIG. 22, the electric motor 110-1 is the same as the electric motor in the fourth embodiment shown in FIGS. 20 and 21, and N w All of the U-phase, V-phase, and W-phase windings are drawn out to the outside of the motor. In the motor applied to the fifth embodiment, similarly to the motors of the first to third embodiments, the U-phase, V-phase, and W-phase windings of the stator are each made up of a plurality of N w Windings U k , V k , W k (k=1, 2, …, N w ) may be connected in series or parallel to form a set of polyphase windings with terminals U, V, and W drawn out to a terminal box (not shown) of the motor. Furthermore, motor 110-1 may be a generator dedicated to power generation, as it is operated as a generator by another external drive motor 115 for external driving.

[0314] The motor 110-1 has a terminal voltage v of the kth winding. uk , v vk , v wk (k=1, 2, …, N w ) can be measured at the terminal TU k and TNU k , TV k and TNV k , T.W. k and TNW k (k=1, 2, …, N w ) are provided and are drawn out to a terminal box (not shown) of the electric motor 110-1. In addition, the current i uk , i vk , i wk (k=1, 2, …, N w ) so that the terminal TU k and TNU k Between TV k and TNV k Between, T.W. k and TNW k Between (k=1, 2,…, N w ) to the current sensor S uk , S vk , S wk (k=1, 2, …, N w ) (not shown) are provided.k and TNU k , TV k and TNV k , T.W. k and TNW k (k=1, 2, …, N w ) is open and not supplying power to a load device (not shown), a current sensor may not be required.

[0315] [External drive motor] The external driving motor 115 is a motor for operating a motor as a generator. The external driving motor 115 may be any type of motor, such as a direct current, single-phase alternating current, or polyphase alternating current motor. In the fifth embodiment, the external driving motor 115 is a three-phase alternating current motor. The external driving motor 115 is driven by an external driving power supply 242 suitable for it.

[0316] The external driving motor 115 and the electric motor 110-1 are connected by a coupling 113 at their respective drive shafts 112, 117, and the external driving motor 115 is operated as a motor, causing the electric motor 110-1 to operate as a generator.

[0317] [Motor voltage and current measuring unit, coordinate conversion unit, and eccentricity calculation device] Terminal voltage v of the kth winding of the electric motor 110-1 uk , v vk , v wk and the winding current i uk , i vk , i wk (k=1, 2, …, N w The voltage and current measuring unit 332 for the motor 110-1 is provided to measure the voltage and current of the terminal TU of the motor. k and TNU k , TV k and TNV k , T.W. k and TNW k , respectively N w One end of the voltage sensor cable for each phase is connected to the terminal TU k and TNU k Between TV k and TNV k Between, T.W. k and TNWk Current sensor S installed between uk , S vk , S wk are N w One end of each of the current sensor cables for each of the phases is connected to the voltage / current measuring unit 332, and the other end of each of the sensor cables is connected to the voltage / current measuring unit 332. uk , v vk , v wk and the winding current i uk , i vk , i wk (k=1, 2, …, N w ) is measured.

[0318] Furthermore, the coordinate conversion unit 342 converts the terminal voltage v of the k-th winding of the electric motor 110-1 into uk , v vk , v wk and the winding current i uk , i vk , i wk (k=1, 2, …, N w ) and the position θ obtained by the motor position sensor 116 re Using equations (1) and (2), the DC axis voltage of the kth winding, v dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck (k=1, 2, …, N w ) and perform a rotational coordinate transformation.

[0319] Here, the motor shown in FIG. 20 and FIG. 21 has a k-th winding (k=1, 2, ..., N w ) terminal TNU k , T.N.V. k , TNW k are connected independently to each winding. In this case, the line voltage v of the kth winding is uvk , v vwk , v wuk Measure the DC axis voltage v using the following formula. dck , qc-axis voltage v qck You can also ask for:

[0320]

number

[0321] however, v dck : DC axis voltage of the kth winding (k=1, 2, ..., N w ) v qck : qc-axis voltage of the kth winding (k=1, 2, ..., N w ) v uvk : Terminal TU of the kth winding k and terminal TV k Voltage between (k=1, 2, …, N w ) v vwk : Terminal TV of the kth winding k and terminal TW k Voltage between (k=1, 2, …, N w ) v wuk : Terminal TW of the kth winding k and terminal TU k Voltage between (k=1, 2, …, N w ) θ re The position may be a position (electrical angle) detected by a motor position sensor or a position estimated and calculated from voltage and current information, or a position at a certain angle φ (φ is arbitrary) from such a detected or estimated position.

[0322] According to equation (22), terminal TNU k , T.N.V. k , TNW k Even in the case of a motor that is not drawn out, the DC shaft voltage V dck , qc-axis voltage v qck can be obtained.

[0323] position θ re A value estimated and calculated from voltage and current information may be used for the motor position sensor 116, and the motor position sensor 116 is not necessarily required.

[0324] However, if the position acquired value from the motor position sensor 116 is not used, it is necessary to simultaneously measure the voltage and current acquired values ​​of each winding to clarify the phase relationship of the voltage and current of each winding. Simultaneous measurement of all windings is difficult, and if, for example, only two windings can be measured simultaneously, the same effect as simultaneous measurement of all windings can be obtained by using one winding as a reference and measuring the other windings simultaneously with the reference winding.

[0325] The eccentricity calculation device 300 calculates the v of the k-th winding. dck , v qck , i dck , i qck (k=1, 2, …, N w The amount of eccentricity is calculated from the value of ) and the motor constants. The method for calculating the amount of eccentricity is the same as in the first and second embodiments, so a description thereof will be omitted.

[0326] The eccentricity amount display device 350 and the abnormality warning device 360 ​​are also similar to those in the first embodiment, and therefore their explanation will be omitted.

[0327] [Hardware Configuration of the Eccentricity Calculation Device for a Rotating Electric Machine of the Fifth Embodiment] The hardware configuration of the device for calculating the eccentricity of a rotary electric machine according to the fifth embodiment is the same as that of the first embodiment shown in the block diagram of FIG. 5, and therefore a description thereof will be omitted.

[0328] In the fifth embodiment, the amount of eccentricity can be calculated by operating the motor 110-1 as a generator using the external driving motor 115, so that the amount of eccentricity can be calculated even in an environment where there is no current control device for the motor 110-1. Furthermore, since this method does not require a current control device, it goes without saying that the amount of eccentricity can be similarly calculated for a motor that is not externally driven but is operated by being directly connected to an AC power source, or for a motor that is operated by open-loop voltage control (for example, V / F control) without current feedback.

[0329] <Sixth embodiment of device and method for calculating eccentricity of rotating electric machine> The sixth embodiment shows a specific example of a servo press machine incorporating an electric motor, to which the device and method for calculating the eccentricity of a rotary electric machine are applied. Here, an example in which the press machine is a crank press is shown, but the present invention may also be applied to servo press machines with various mechanisms such as a knuckle mechanism or a link mechanism, in addition to a crank mechanism.

[0330] Fig. 23 is a schematic view of the servo press machine shown in Fig. 1. In Fig. 23, parts that are common to the servo press machine 100 shown in Fig. 1 are given the same reference numerals.

[0331] 23, a servo press machine 100 incorporates an electric motor 110, which is the power source of the servo press machine 100. A main gear 120 meshes with a gear 114 provided on a drive shaft 112 of the electric motor 110, and the crank mechanism (crankshaft 130, connecting rod 140) of the servo press machine 100 is connected to the main gear 120. The electric motor 110 is a polyphase AC motor as described in the above-mentioned embodiments.

[0332] The slide 150 can be raised and lowered relative to the stationary bolster 160 by a crank mechanism.

[0333] An upper die 152 is attached to the slide 150, and a lower die 162 is attached to the bolster 160. When a workpiece 194 is between the upper die 152 and the lower die 162, the slide 150 is lowered to bring the upper die 152 and the lower die 162 into contact, thereby allowing press working to be performed on the workpiece 194. Figure 23 shows a state in which the workpiece 194, which is a coiled sheet material, is being fed to the servo press machine 100 by the feeder 192.

[0334] A crankshaft position sensor 132 is attached to the crankshaft 130 of the servo press machine 100, which is simply shown in FIG. 1 etc., so that the position of the crankshaft 130 can be grasped. A rotary encoder or the like is used as the crankshaft position sensor 132. Position information θ of the crankshaft 130 acquired by the crankshaft position sensor 132rc is input to the host control device 210, and based on this information, the position of the slide 150 of the servo press machine 100 can be controlled.

[0335] The servo press machine 100 is freely driven to rotate by the forward, reverse, and variable speed control of the electric motor 110, so it can be freely set to various slide motions, such as not only a crank mechanism but also other mechanisms, slide motions suitable for compacts including stationary ones, or forward and reverse pendulum motions, and can be switched between these. This allows for greater precision, productivity, and adaptability to press-molded products.

[0336] The amount of eccentricity can be measured, for example, when the servo press machine 100 is in a state where the motor is stationary during preparation for operation, and when the motor is operating during slide drive.

[0337] First, the general methods for starting, operating, and stopping the servo press machine 100 will be described with reference to the flowchart in FIG.

[0338] Before starting, the servo press machine 100 is stationary and the power is not turned on.

[0339] First, in step S21, the press operator turns the main breaker 184 provided on the control panel 182 shown in FIG. 23 from OFF to ON in order to start the servo press machine 100. When turned ON, the main power lamp 180e on the main operation panel 180 shown in FIG. 25 lights up.

[0340] Next, in step S22, the press operator turns the operation power switch (key switch) 180f of the main operation panel 180 from "off" to "on." When turned "on," the operation display 180g of the main operation panel 180 is powered on, allowing the operator to display the current slide position during servo press operation, set the motion and speed of the slide 150, and switch between the eccentricity calculation mode and normal operation mode of the electric motor 110 described in the first embodiment. In addition, the main operation panel 180 is connected to and communicates with the electric motor control device shown in FIG. 1, and can also display the eccentricity calculation value and abnormality alarm contents described in the previous embodiment on the operation display 180g.

[0341] Next, in step S23, the operator turns on the oil supply pump button (with lamp) 180c on the main operation panel 180. When the oil supply pump button 180c is turned on, the lamp on the oil supply pump button 180c flashes, and machine oil begins to be supplied to the drive parts of the servo press machine 100 (for example, the gear 114 of the drive shaft 112 of the electric motor 110 and the main gear 120 of the crankshaft 130) and the bearings (not shown) of the electric motor 110. After oil supply has been carried out for a predetermined time, the lamp on the oil supply pump button 180c changes from flashing to a constant light, and oil supply is completed.

[0342] Next, in step S24, the press operator turns on the servo power ON button (with lamp) 180a on the main operation panel 180 to supply energy to the energy storage capacitor (not shown; connected to the DC circuit between the converter 250 and the servo amplifier (inverter) 260 in FIG. 1) of the motor control device. When the servo power ON button 180a is turned on, the lamp of the servo power OFF button 180b, which had been constantly lit until then, goes out, the lamp of the servo power ON button 180a starts flashing, and electrical energy for operating the motor 110 begins to be stored. When the supply of energy to the energy storage capacitor is complete, the operation display 180g displays a message indicating that the servo press machine 100 is ready to operate. In addition, the operable lamp 180d on the main operation panel 180 turns on. In addition, the brake 170 of the electric motor 110 opens.

[0343] Next, in step S25, the press operator switches the operation selection switch 190e of the operation button box 190 shown in FIG. 26 from "OFF" to the operation mode they desire to operate the slide 150 of the servo press machine 100. One of the operation modes of the servo press machine 100 is the "inching operation mode." In this mode, the slide 150 moves according to the preset motion while the operation button 190d of the operation button box 190 shown in FIG. 26 is pressed, and immediately stops when the operation button 190d is released. In addition, in the "continuous operation mode," pressing the button 190f with the continuous preparation lamp on the operation button box 190 and then pressing the operation button 190d within a predetermined time period causes the slide 150 to continuously operate according to the preset motion. The continuous operation continues even after the operation button 190d is released, and pressing the set point stop button 190b causes the slide to stop at the preset slide position. Here, it is assumed that the continuous operation mode has been selected.

[0344] In step S26, the press operator presses the button 190f with continuous preparation lamp on the operation button box 190. Next, the press operator presses the operation button 190d within a predetermined time after pressing the button 190f with continuous preparation lamp. There are two operation buttons 190d, one on the left and one on the right, and the slide cannot be driven unless both are pressed. In the continuous operation mode, pressing the operation button 190d once drives the slide 150, and the slide 150 continues to move even after being released.

[0345] To stop the slide drive (step S27), the press operator presses the set point stop button 190b on the operation button box 190. This stops the slide 150 when it reaches the set position. To bring the servo press machine 100 to an emergency stop, the emergency stop button 190c is pressed, and the slide 150 immediately stops.

[0346] When it is desired to turn off the power to the servo press machine 100 (step S28), the operator first turns on the servo power-off button 180b on the main operation panel 180. When the servo power-off button 180b is turned on, the energy stored in the energy storage capacitor is released, and the electric motor 110 cannot be driven.

[0347] In step S29, the operation power switch (key switch) 180f is turned from "on" to "off" to turn off the power to all devices (except the main operation panel) of the servo press machine 100.

[0348] In step S30, the main breaker 184 provided on the control panel 182 is turned from ON to OFF. The main power lamp 180e on the main operation panel 180 is turned off, and all power to the servo press machine 100 is turned OFF.

[0349] [Calculating eccentricity when the motor is stationary during preparation for operation] The calculation of the eccentricity amount when the motor is stationary during the preparation stage for operation of the servo press machine 100 is performed in step S24.

[0350] Specifically, after the servo power ON button (with lamp) 180a is turned ON and energy supply to the energy storage capacitor is completed, the electric motor 110 is energized to calculate the eccentricity. Since the slide 150 cannot be driven without the operation of the press operator, the brake 170 of the electric motor 110 is closed as in the eccentricity calculation mode of the third embodiment, and the rotor of the electric motor 110 is locked. Then, as in the third embodiment, the magnetic flux chain of the electric motor winding is To obtain the voltage related to the crossover, the dc axis current command i dc * , qc axis current command i qc * is controlled to be a steady AC current, and the dc axis current i dck , qc axis current i qck DC axis voltage V when is a steady AC current dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck (k=1, 2, …, N w ) and the motor constants. As described in the third embodiment, the dc-axis current command i dc * , qc axis current command i qc *is not necessarily a steady AC current, but may be a current command that generates a voltage related to the magnetic flux linkage of the motor windings, for example, a step-like or ramp-like current command.

[0351] This current command is specified in advance by the designer, so the DC axis voltage V dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck The map of voltage and air gap length related to magnetic flux linkage is obtained by measuring or analyzing the above and calculating the eccentricity amount, i.e., v dck -R ak ×i dck , v qck -R ak ×i qck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) and the gap length L gk or the orthogonal projection components in the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction) of the voltage space vector related to the magnetic flux linkage of each winding are calculated, and a map of the eccentricity of two axes orthogonal to the X-axis resultant voltage Vsx and the Y-axis resultant voltage Vsy, which are the sums of these, is calculated, and the values ​​are stored in memory 380 and also in a memory inside the control device for the motor.

[0352] These values ​​and the dc shaft voltage v dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck From the measured values, the amount of eccentricity can be calculated in the same manner as in the above-described embodiment.

[0353] Eccentricity, gap length L gk After calculating one or more of the X-axis direction composite voltage Vsx and the Y-axis direction composite voltage Vsy, the eccentricity and the air gap length L gkIf at least one of the X-axis direction composite voltage Vsx and the Y-axis direction composite voltage Vsy does not exceed the threshold, the operation display 180g displays a message indicating that the servo press machine 100 is ready to operate. gk If either one or more of the X-axis composite voltage Vsx and the Y-axis composite voltage Vsy exceeds the threshold, the eccentricity value and the air gap length L are displayed on the operation display 180g as shown in Figure 27. gk It also displays the presence or absence of one or more of the X-axis direction composite voltage Vsx and the Y-axis direction composite voltage Vsy, as well as any abnormalities.

[0354] [Calculating eccentricity while the motor is running during slide drive] In the case of calculating the amount of eccentricity while the motor is operating during slide drive, after the operation preparation is completed in step S24, the eccentricity calculation mode is selected on the operation display 180g from the mode selection unit 212 described in the first embodiment. Fig. 28 shows an example of the screen of the operation display 180g when the eccentricity calculation mode is selected. The screen has areas for displaying the value of the amount of eccentricity and the presence or absence of an abnormality, but at this point, the columns for displaying the value of the amount of eccentricity and the presence or absence of an abnormality are blank.

[0355] In the eccentricity calculation mode for a servo press machine 100 having a crank mechanism, for example, a motion is set so that the crankshaft 130 moves at a constant speed, i.e., the drive shaft 112 of the electric motor 110 moves at a constant speed. This is set by selecting "Standard" on the operation display 180g shown in Figure 28. This motion is specified in advance by the press designer, so the DC shaft voltage V in that motion can be calculated in advance. dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck The map of voltage and air gap length related to magnetic flux linkage is obtained by measuring or analyzing the above and calculating the eccentricity amount, i.e., v dck -R ak ×i dck , v qck -R ak ×i qck , or (v dck -R ak ×i dck , vqck -R ak ×i qck ) and the gap length L gk or the orthogonal projection components in the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction) of the voltage space vector related to the magnetic flux linkage of each winding are calculated, and a map of the eccentricity amounts of the two axes orthogonal to the X-axis resultant voltage Vsx and the Y-axis resultant voltage Vsy, which are the sums of these, is calculated, and the values ​​are stored in memory 380 and are also displayed on the operation display 180g as shown in FIG. 28.

[0356] In Figure 28, as an example, only the coefficients of the approximate equation for the map of voltage related to the air gap length and magnetic flux linkage are displayed, but the map itself may also be shown. If "Standard" is selected, the area that displays the coefficients of the approximate equation for the map cannot be changed using the touch panel, and is displayed in gray, for example.

[0357] When "Standard" is selected, the motion will differ from the motion set by the press operator. However, if "Optional" is selected as shown in Figure 29, the eccentricity can be calculated using the motion set by the press operator. In this case, the DC axis voltage V dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck The map of voltage and air gap length related to magnetic flux linkage, i.e., v dck -R ak ×i dck , v qck -R ak ×i qck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) and the gap length L gkThe horizontal (X-axis direction) and vertical (Y-axis direction) orthogonal projection components of the voltage space vector related to the magnetic flux linkage of each winding are calculated, and a map of the eccentricity of the two axes orthogonal to the sum of the X-axis resultant voltage Vsx and the Y-axis resultant voltage Vsy is calculated in advance.

[0358] When "Arbitrary" is selected, the map of voltage and air gap length related to magnetic flux linkage, i.e., v dck -R ak ×i dck , v qck -R ak ×i qck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) and the gap length L gk The area for inputting (displaying) the map of the relationship between the voltage and air gap length related to the magnetic flux linkage in the motion set by the press operator, i.e., the map of the horizontal (X-axis) and vertical (Y-axis) orthogonal projection components of the voltage space vector related to the magnetic flux linkage in each winding, and the sum of these, the X-axis resultant voltage Vsx and the Y-axis resultant voltage Vsy, and the map of the eccentricity of the two axes orthogonal to each other, is displayed in white, and can be input using the touch panel. dck -R ak ×i dck , v qck -R ak ×i qck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) and the gap length L gk or the orthogonal projection components in the horizontal direction (X-axis direction) and vertical direction (Y-axis direction) of the voltage space vector related to the magnetic flux linkage of each winding are calculated, and the values ​​of the map of the eccentricity of the two axes orthogonal to the X-axis resultant voltage Vsx and the Y-axis resultant voltage Vsy, which are their sums, can be input and stored in memory 380. Here, it is assumed that "standard" is selected.

[0359] In step S26, pressing the operation button 190d drives the slide 150. When the drive shaft 112 of the electric motor 110 moves at a constant speed and the load on the electric motor 110 is substantially constant, the dc shaft voltage v dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck The average value of is nearly constant, and the amount of eccentricity can be calculated from the measured values, as in the previous embodiment. In particular, when the slide 150 is at its highest position (near the top dead center), the mass of the slide 150 is applied only in the vertical direction of the crankshaft 130. In other words, no rotational force to hold the slide mass is applied to the crankshaft 130, and almost no load torque is applied to the electric motor 110. In addition, no pressing work is performed near the top dead center. Due to these two factors, the rotational torque of the electric motor 110 is small near the top dead center. The position of the crankshaft 130 is detected by the crankshaft position sensor 132 and output to the upper control device 210, so the DC shaft voltage V when the crankshaft position sensor 132 detects a position near the top dead center is dck , qc-axis voltage v qck , dc axis current i dck , qc axis current i qck Since the current value is small near the top dead center, i in Equations (3) to (5) and Equations (11) to (16) can be measured. dck , i qck This provides a special effect of reducing the influence of the motor constants including the term and their fluctuations.

[0360] In addition, in the eccentricity calculation mode when the motor is operating during slide drive, the brake 170 is in the open position, but the brake 170 may be closed to calculate the eccentricity when the motor is stationary, similar to the method used in the operation preparation stage.

[0361] When the calculation of the amount of eccentricity is completed, the operation display 180g displays the value of the amount of eccentricity, the presence or absence of abnormalities, etc. Figure 30 shows an example of the screen of the operation display 180g after the amount of eccentricity has been calculated.

[0362] For normal operation, if normal operation mode is selected on the operation display 180g as shown in Figure 31, the press can be operated with the motion set by the press operator. In normal operation mode, the operation display 180g displays "standard", "arbitrary", and a map of voltage and air gap length related to magnetic flux linkage, i.e., v dck -R ak ×i dck , v qck -R ak ×i qck , or (v dck -R ak ×i dck , v qck -R ak ×i qck ) and the gap length L gk Alternatively, the horizontal (X-axis direction) and vertical (Y-axis direction) orthogonal projection components of the voltage space vector related to the magnetic flux linkage of each winding are calculated, and the sum of these components is used to calculate the X-axis resultant voltage Vsx and the Y-axis resultant voltage Vsy, as well as a map of the eccentricity on two axes orthogonal to each other. The "eccentricity threshold," "eccentricity," and "presence or absence of abnormality" are not displayed, but they may be displayed.

[0363] In addition, the displayed values ​​are not only the eccentricity threshold and the eccentricity, but also the aforementioned gap length L gk The threshold of the X-axis composite voltage Vsx, the Y-axis composite voltage Vsy, and the L gk You can also display the Vsx and Vsy values.

[0364] [others] In this embodiment, the hardware structure of a processing unit that executes various processes, such as the processor of the eccentricity calculation device, is various processors as follows: The various processors include a CPU (Central Processing Unit), which is a general-purpose processor that executes software (programs) and functions as various processing units, a programmable logic device (PLD), such as an FPGA (Field Programmable Gate Array), whose circuit configuration can be changed after manufacture, and a dedicated electric circuit, such as an ASIC (Application Specific Integrated Circuit), which is a processor having a circuit configuration designed specifically for executing specific processes.

[0365] One processing unit may be configured with one of these various processors, or may be configured with two or more processors of the same or different types (for example, multiple FPGAs, or a combination of a CPU and an FPGA). Also, multiple processing units may be configured with one processor. An example of multiple processing units being configured with one processor is, first, a combination of one or more CPUs and software, as typified by computers such as a client or server. In one form, multiple processors are combined to form a single processor, which functions as multiple processing units. Secondly, there is a form in which a processor is used to realize the functions of an entire system including multiple processing units on a single IC (Integrated Circuit) chip, as typified by a System on Chip (SoC). In this way, the various processing units are configured as a hardware structure using one or more of the above-mentioned various processors.

[0366] Furthermore, the hardware structure of these various processors is, more specifically, an electric circuit made up of a combination of circuit elements such as semiconductor elements.

[0367] Furthermore, the present invention is not limited to the above-described embodiment, but includes various modifications. The above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0368] [Appendix 1] Proof of Theorem 1 (Equation (8)) [Theorem 1] A circle (equation of the circle: (x-a1 ' ) 2 +(y-a2 ' ) 2 =r 2 ) and N drawn at equal intervals of angle θ from the origin O w pieces(N w ≧4 and N w The coordinates of the intersections with the group of lines (x1, y1), (x2, y2), ..., (x k ,y k ), …, (x Nw ,y Nw ), the coordinates of the center point of the circle (a1 ' ,a2 ' ) is expressed by the above-mentioned equation (8). Figure 32 shows this situation.

[0369] [Proof] First, the half-line group l k (k=1,2,…,N w ) among them, let l k Then, this half line l k and the intersection of the circle (x k ,y k ) can be calculated using the following procedure.

[0370] half line l k The equation for l l is expressed by the following equation, where α is the angle between the x-axis and the

[0371]

number

[0372] The equation of a circle is, if the radius of the circle is r,

[0373]

number

[0374] By solving equations (23) and (24) simultaneously for x, we get x=x k So, the following formula is obtained:

[0375]

number

[0376] From equation (25), x k Two solutions are obtained, but since this is an intersection with a group of half-lines, one of them is the x-coordinate of the intersection of the circle.

[0377] or

[0378]

number

[0379] Next, if the ray group is even, then the ray l k Another half line l that is collinear with m The intersection point with the circle is (x m ,y m ) This situation is shown in Figure 33.

[0380] half line l k and half line l m are on the same line, so the half line l m The x-coordinate of the intersection of the circle and the half line l is one of the two x-coordinates in equation (25). k and the x-coordinate other than the x-coordinate of the circle intersection.

[0381] Here, as shown in FIG. 34, the coordinates of the center point (a1 ' ,a2 ' ) to the half line l k If you draw a perpendicular line to the point (x k ,y k ), (x m ,y m ) and the circle. k or half line l m The coordinates of the intersection of (x hk ,y hk ), the following equation is obtained:

[0382]

number

[0383] x in equation (27) hk Substituting equation (25) into

[0384]

number

[0385] (However, if (k-1)θ+α≠π / 2, 3π / 2) From equations (23) and (28), the following equation is obtained:

[0386]

number

[0387] (However, if (k-1)θ+α≠π / 2, 3π / 2) Also, when (k-1)θ+α=π / 2, 3π / 2, from equation (26), x k =0, and x m =0, so x in equation (27) hk About x k =0, x m Substituting =0, we get the following equation.

[0388]

number

[0389] (However, when (k-1)θ+α=π / 2, 3π / 2) Furthermore, when (k-1)θ+α=π / 2,3π / 2, substituting x=0 into equation (24), y=y k As a result, the following equation is obtained.

[0390]

number

[0391] (However, when (k-1)θ+α=π / 2, 3π / 2) Therefore, from equation (27) and equation (31), y hk is expressed as follows:

[0392]

number

[0393] Here, by substituting (k-1)θ+α=π / 2, 3π / 2 into equations (28) and (29), we get x hk =0, y hk =a2, which coincides with equations (30) and (32), so equations (28) and (29) hold regardless of (k-1)θ+α.

[0394] Therefore, (x hk ,y hk ) is expressed as follows:

[0395]

number

[0396] (k=1,2,…,N w ) k=1,2,…,N in Eq.(33) w If we calculate the sum of the left and right sides of

[0397]

number

[0398] The left side of equation (34) is clearly expressed as follows from equation (27):

[0399]

number

[0400] The first line of the second term on the right side of equation (34) is the real part of the following equation, and the second line of the second term is the imaginary part of the following equation.

[0401] Also, the first line of the third term on the right-hand side is the imaginary part of the following equation, and the second line of the third term is the real part of the following equation multiplied by -1.

[0402]

number

[0403] By calculating equation (36), the following equation is obtained from the formula for the sum of geometric series.

[0404]

number

[0405] where N w The angles formed by the group of half-lines are equally spaced θ, so the following equation holds:

[0406]

number

[0407] Substituting equation (38) into equation (37), N w If is an even number greater than or equal to 4, then

[0408]

number

[0409] According to equation (39), the second and third terms on the right-hand side of equation (34) are both 0, so only the first term remains on the right-hand side of equation (34).

[0410] From the above, equation (34) becomes the following equation.

[0411]

number

[0412] 2 / N on both sides of equation (40) w By multiplying by , we obtain equation (8). From the above, we can see that the half-line group l k (k=1,2,…,N w )N w It has been proven that equation (8) holds when is an even number greater than or equal to 4.

[0413] [Appendix 2] Proof of Theorem 2 (Equation (9)) [Theorem 2] A circle (equation of the circle: (x-a1 ' ) 2 +(y-a2 ' ) 2 =r 2 ) and N drawn at equal intervals of angle θ from the origin O w pieces(N w ≧3 and N w The coordinates of the intersections with the group of lines (x1, y1), (x2, y2), ..., (x k ,y k ), …, (x Nw ,y Nw ), the coordinates of the center point of the circle (a1 ' ,a2 ' ) is the radius of the circle r, and the coordinates of the center point of the circle (a1 ' ,a2 ' ) vector sum √(a1 '2 +a2 '2 ), when it is sufficiently large, it is expressed by the above-mentioned equation (9).

[0414] [Proof] The x-coordinate of the intersection of the group of ray lines and the circle is as shown in the above-mentioned equation (25).

[0415] Equation (25) represents the x-coordinate of the intersection of the line and the circle shown in equation (23), but since equation (23) is a group of half lines, there is an extra solution. In this case, you can select an appropriate value as shown in equation (41) or equation (42) depending on (k-1)θ+α.

[0416]

number

[0417]

number

[0418] In addition, when (k-1)θ+α=π / 2, 3π / 2, as shown in equation (26), x k =0.

[0419] Here, c=a1+a2tan[(k-1)θ+α], d=1+tan 2 [(k-1)θ+α], e=(a1 2 +a2 2 -r 2 ), then equations (41) and (42) become the following equations.

[0420]

number

[0421]

number

[0422]

number

[0423] In equation (45), √(a1 '2 +a2 '2 )≪r, the first term is √(-[1+tan 2 [(k-1)θ+α]](-r 2 )) and from the second term onwards, a1+a2tan[(k-1)θ+α] can be approximated as √(-[1+tan 2 [(k-1)θ+α]](a1 2 +a2 2 -r 2 ), it is small enough that it can be approximated to almost 0. 2 +a2 2 )≪r, equation (43) can be approximated as follows:

[0424]

number

[0425] In addition, the following equation holds true:

[0426]

number

[0427]

number

[0428]

number

[0429]

number

[0430] (where (k-1)θ+α≠π / 2, 3π / 2) Furthermore, from equation (50) and equation (23), the following equation holds:

[0431]

number

[0432] Substituting (k-1)θ+α=π / 2,3π / 2 into equation (50), x k ≒0. In this case, the equation (26)(x k =0).

[0433] Also, substituting (k-1)θ+α=π / 2,3π / 2 into equation (51), y k ≒ a2 ± r, and in equation (31), the radius r of the circle is the coordinate of the center point of the circle (a1 ' ,a2 ' ) vector sum √(a1 '2 +a2 '2 ) for which the value y is approximately valid when it is sufficiently large. k ≒ a2±r. Therefore, equations (50) and (51) hold regardless of (k-1)θ+α.

[0434] Equation (50) and equation (51) can be expressed as a matrix:

[0435]

number

[0436]

number

[0437] The second and third terms on the right side of equation (53) are equal to the second and third terms on the right side of equation (34), and are therefore 0.

[0438] Furthermore, the first line of the fourth term on the right side of equation (53) is the real part of the following equation, and the second line of the fourth term is the imaginary part of the following equation:

[0439]

number

[0440]

number

[0441] where N w The angles between the half-lines are equally spaced θ, so θ=2π / N w Substituting (Equation (38)) into Equation (55), the following equation is obtained.

[0442]

number

[0443]

number

[0444] 2 / N on both sides of equation (57) w By multiplying by, we obtain equation (9). From the above, the half-line group lk (k=1,2,…,N w )N w is an odd number greater than or equal to 3, and √(a1 2 +a2 2 It has been proven that equation (9) holds approximately when r<<. [Explanation of symbols]

[0445] 100...Servo press machine 110, 110-1...Electric motor 110a...Stator 110b...Rotor 112...Drive shaft 113...Coupling 114...Gear 115...External drive motor 116...Motor position sensor 117...Drive shaft 120...Main gear 130...Crankshaft 132...Crankshaft position sensor 140...Connecting rod 150...slide 152...Upper mold 160...Bolster 162…Lower mold 170...Brake 172...Brake control unit 180…Main operation panel 180a...Servo power on button 180b...Servo power off button 180c…Fuel pump button 180d...Operable lamp 180e...Main power lamp 180g...Operation display 182...Control panel 184...Main breaker 190...Operation button box 190b...Setpoint stop button 190c...Emergency stop button 190d...Drive button 190e... Operation selection switch 190f...Continuous preparation lamp button 192...Feeding device 194…Processing materials 210... Upper control device 212...Mode selection section 213...Speed ​​control section 214…Speed ​​calculation section 216...DC-QC axis current command calculation section 216A: dc-axis current command and qc-axis current command calculation unit for eccentricity calculation mode 216B: DC axis current command and qc axis current command calculation unit for normal operation mode 220, 220-1 to 220-N w ...Current control device 230...Current control section 232...dc axis current control section 234...qc axis current control section 236, 238, 340, 342... Coordinate conversion section 242…External drive power supply 250...Converter 260...Servo amplifier 270...PWM conversion section 280...Current sensor 300...Eccentricity calculation device 310...Gap length calculation section 320... Composite voltage calculation unit 330...Eccentricity calculation section 331, 332...Voltage and current measurement section 350...Eccentricity display device 360…Abnormality alarm device 370...processor 380…Memory 390... Input / output interface S1~S7, S11~14, S21~S30...Step

Claims

1. An apparatus for calculating an amount of eccentricity of a rotary electric machine, the apparatus comprising: a processor; and a memory for storing constants and an eccentricity calculation formula of a polyphase rotary electric machine, The processor: obtaining a voltage command for each phase winding of the rotary electric machine that has been coordinate-transformed into a DC-QC coordinate system for control, or a voltage obtained by transforming a multiphase voltage applied to the windings of each phase into a DC-QC coordinate system for control, and a current command for each phase winding that has been coordinate-transformed into a DC-QC coordinate system for control, or a current obtained by transforming a multiphase current flowing through the windings of each phase into a DC-QC coordinate system for control, calculating the eccentricity of the rotary electric machine based on the acquired voltage command or the voltage, the acquired current command or the current, and the constants of the rotary electric machine and an eccentricity calculation formula stored in the memory; A device for calculating the eccentricity of rotating electric machines.

2. the arithmetic formula includes a first arithmetic formula that indicates a relationship between a voltage related to magnetic flux linkage and an air gap length between the rotor and a stator of the rotary electric machine when the rotor of the rotary electric machine is eccentric with respect to a representative circumferential position of a specific winding and is operated under specific operating conditions, the first arithmetic formula being obtained from a map of the air gap length between the rotor and the stator of the rotary electric machine and the voltage related to magnetic flux linkage in the specific winding; the processor calculates a voltage related to the magnetic flux linkage from the acquired voltage command or the voltage and the acquired current command or the current, for each winding when operated under the same operating conditions as the specific operating conditions; Substituting the voltage related to the calculated magnetic flux linkage into the first calculation formula to obtain an air gap length corresponding to each of the windings, and calculating an eccentricity of the rotary electric machine from the obtained air gap length. The apparatus for calculating the eccentricity of a rotary electric machine according to claim 1.

3. the constants include dimensions of a stator of the rotary dynamoelectric machine; the processor calculates coordinates of a plurality of points through which the outermost circle of the rotor passes in a coordinate system having the center of the stator as its origin, based on the air gap lengths corresponding to the respective windings and the dimensions of the stator; calculating an eccentricity of the rotary electric machine based on the coordinates of the calculated plurality of points; The apparatus for calculating the eccentricity of a rotary electric machine according to claim 2.

4. the arithmetic expressions include a second arithmetic expression for calculating the center of a circle passing through three points from the coordinates of the three points, The processor: If the calculated number of points is three, use the coordinates of the three points, and if the calculated number of points is more than three, select three points; calculating the eccentricity of the rotary electric machine using the coordinates of the selected three points and the second calculation formula; 4. The apparatus for calculating the eccentricity of a rotary electric machine according to claim 3.

5. the arithmetic expressions include a second arithmetic expression for calculating the sum of squares of absolute values ​​of errors obtained by substituting the calculated coordinates of the plurality of points into an equation of a circle having a radius included in the dimensions of the rotor, the processor searches for coordinates of the center of the rotor that minimize the sum calculated by the second arithmetic expression; 4. The apparatus for calculating the eccentricity of a rotary electric machine according to claim 3.

6. the arithmetic formula includes a second arithmetic formula for calculating a value obtained by doubling the arithmetic mean of x-coordinates and a value obtained by doubling the arithmetic mean of y-coordinates of coordinates of a plurality of points calculated from the air gap lengths of the winding at equally spaced angles, the processor calculates the x-coordinate and the y-coordinate of the center of the rotor based on the calculated coordinates of the plurality of points and the second arithmetic expression.

4. The apparatus for calculating the eccentricity of a rotary electric machine according to claim 3.

7. the calculation formula includes: a first approximation formula created from a first map showing a relationship between a first direction resultant voltage, which is a sum of orthogonal projection components in the first direction of a voltage space vector calculated from a representative circumferential position and a voltage related to a magnetic flux linkage of each winding, and an amount of eccentricity in the first direction, when a rotor of the rotary electric machine is eccentric in a first direction and a second direction orthogonal to the first direction and is operated under specific operating conditions; and a second approximation formula created from a second map showing a relationship between a second direction resultant voltage, which is a sum of orthogonal projection components in the second direction, and an amount of eccentricity in the second direction, the processor calculates a voltage related to the magnetic flux linkage from the acquired voltage command or the voltage and the acquired current command or the current, for each winding when operated under the same operating conditions as the specific operating conditions; calculating a first direction resultant voltage, which is the sum of orthogonal projection components of the voltage space vector in the first direction, and a second direction resultant voltage, which is the sum of orthogonal projection components of the voltage space vector in the second direction, based on the voltage related to the calculated magnetic flux linkage corresponding to each winding and a representative circumferential position of each winding; calculating an amount of eccentricity of the rotor in the first direction by substituting a first direction resultant voltage, which is the calculated sum of orthogonal projection components in the first direction, into the first approximate formula, and calculating an amount of eccentricity of the rotor in the second direction by substituting a second direction resultant voltage, which is the calculated sum of orthogonal projection components in the second direction, into the second approximate formula; The apparatus for calculating the eccentricity of a rotary electric machine according to claim 1.

8. the constants include a phase resistance of the rotary electric machine; the processor calculates a voltage related to the magnetic flux linkage based on the acquired voltage command or the voltage, the current command or the current, and the phase resistance. The apparatus for calculating the eccentricity of a rotary electric machine according to claim 2 or 7.

9. The specific operating conditions include an operating condition in which only specific axes of the voltage command or the voltage and the current command or the current that have been coordinate-transformed into the dc-qc coordinates of two orthogonal axes are energized for operation. The apparatus for calculating the eccentricity of a rotary electric machine according to claim 8.

10. the rotating electric machine is an electric motor or a generator; The apparatus for calculating the eccentricity of a rotary electric machine according to any one of claims 1 to 7.

11. A method executed by a rotary electric machine eccentricity calculation device including a processor and a memory that stores constants and eccentricity calculation formulas for a polyphase rotary electric machine, the method comprising: the processor acquires a voltage command for each phase winding of the rotary electric machine that has been coordinate-transformed into a dc-qc coordinate system for control, or a voltage command for each phase winding that has been coordinate-transformed into a dc-qc coordinate system for control, and a current command for each phase winding that has been coordinate-transformed into a dc-qc coordinate system for control, or a current command for each phase winding that has been coordinate-transformed into a dc-qc coordinate system for control, or a current command for each phase winding that has been coordinate-transformed into a dc-qc coordinate system for control, a step of the processor calculating the eccentricity of the rotary electric machine based on the acquired voltage command or the voltage, the acquired current command or the current, and a constant of the rotary electric machine and an eccentricity calculation formula stored in the memory; A method for calculating the eccentricity of a rotating electric machine, comprising:

12. the arithmetic formula includes a first arithmetic formula that indicates a relationship between a voltage related to magnetic flux linkage and an air gap length between the rotor and a stator of the rotary electric machine when the rotor of the rotary electric machine is eccentric with respect to a representative circumferential position of a specific winding and is operated under specific operating conditions, the first arithmetic formula being obtained from a map of the air gap length between the rotor and the stator of the rotary electric machine and the voltage related to magnetic flux linkage in the specific winding; the processor calculates a voltage related to the magnetic flux linkage from the acquired voltage command or the voltage and the acquired current command or the current, for each winding when the motor is operated under the same operating conditions as the specific operating conditions; the step of calculating the eccentricity of the rotary electric machine includes substituting a voltage related to the calculated magnetic flux linkage into the first equation to obtain an air gap length corresponding to each of the windings, and calculating the eccentricity of the rotary electric machine from the obtained air gap length. The method for calculating the eccentricity of a rotary electric machine according to claim 11.

13. a control unit that controls a multi-phase rotary electric machine and causes the rotary electric machine to operate a mechanical device; The eccentricity calculation device for a rotary electric machine according to any one of claims 1 to 7, A control device for a rotating electric machine comprising:

14. a speed control unit that outputs a torque command based on a deviation between a preset speed command for the rotary electric machine and a speed of the rotary electric machine; a mode selection unit that selects, in response to a selection instruction from an operator, a normal operation mode for operating the rotary electric machine normally or an eccentricity calculation mode for calculating an eccentricity; a host control device that outputs a switching signal for switching between the normal operation mode and the eccentricity calculation mode based on a mode command output from the mode selection unit; a current command calculation unit that outputs a dc-axis current command and a qc-axis current command based on the torque command and the switching signal, When the normal operation mode is selected, the control unit outputs a dc-axis current command and a qc-axis current command for the normal operation mode from the current command calculation unit, and when the eccentricity calculation mode is selected, the control unit controls the current command calculation unit to output a dc-axis current command and a qc-axis current command for the eccentricity calculation mode, or controls the dc-axis current command and the qc-axis current command output from the current command calculation unit so that the current command is a steady AC current or a current that generates a voltage related to the magnetic flux linkage of the rotary electric machine.

14. The control device for a rotating electric machine according to claim 13.

15. a display device that displays at least one of the eccentricity, the air gap length, the first direction resultant voltage, and the second direction resultant voltage; the control unit causes the display device to display one or more of the eccentricity calculated by the eccentricity calculation device, the air gap length calculated by the processor corresponding to each of the windings, and the first direction composite voltage and the second direction composite voltage calculated by the processor.

14. The control device for a rotating electric machine according to claim 13.

16. an abnormality alarm device that notifies of abnormality in one or more of the eccentricity, the air gap length, the first direction composite voltage, and the second direction composite voltage; the control unit compares one or more of the eccentricity calculated by the eccentricity calculation device, the air gap length determined by the processor corresponding to each of the windings, and the first direction composite voltage and the second direction composite voltage calculated by the processor with a threshold value serving as an abnormality determination criterion, and causes the abnormality warning device to notify of an abnormality when one or more of the eccentricity, the air gap length, the first direction composite voltage, and the second direction composite voltage are equal to or greater than the threshold value; 14. The control device for a rotating electric machine according to claim 13.

17. the mechanical device is a servo press machine including the rotary electric machine, The rotary electric machine rotates a main shaft of the servo press machine.

14. The control device for a rotating electric machine according to claim 13.

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