Magnetic gap length estimation device, rotating electric machine drive device, rotating electric machine system, and magnetic gap length estimation method

Abstract

A magnetic gap length estimating device (1) of the present application is characterized by comprising a voltage acquisition unit (2) that acquires a line-to-line induction voltage induced at wire connections (9) of an inverter (8) and an electric rotating machine (7) with multiple sets of phases, an estimation information creation unit (3) that creates estimation information for estimating a magnetic gap length from the waveform of a line-to-line induction voltage when the electric rotating machine (7) is rotated at no load, and an instantaneous gap length estimation unit (4) that estimates an instantaneous magnetic gap length from an instantaneous value of the line-to-line induction voltage and the estimation information.

Description

[Technical field]

[0001] The present application relates to a magnetic gap length estimation device, a driving device for a rotating electric machine, a rotating electric machine system, and a magnetic gap length estimation method. [Background technology]

[0002] In rotating electric machines such as electric motors, when eccentricity occurs, such as static eccentricity, which is a misalignment between the central axis of the rotor and the central axis of the stator, or dynamic eccentricity, which is a misalignment between the geometric center of the rotor and the center of rotation, the magnetic gap length between the rotor and the stator fluctuates, resulting in magnetic imbalance. Since magnetic imbalance can cause low-frequency vibrations and noise, it is necessary to suppress eccentricity in rotating electric machines.

[0003] Eccentricity occurs during manufacturing processes for rotating electric machines, such as the rotor assembly process, the rotor insertion process into the stator process, and the process of sealing the rotating shaft with a bracket after insertion, but it can also occur due to problems that occur in the bearing part of the rotor while the rotating electric machine is in operation. Therefore, it is difficult to completely eliminate the variation in magnetic gap length caused by eccentricity in a rotating electric machine, and technology is required to detect and correct eccentricity during the manufacturing process, and technology to detect eccentricity by analyzing the current and voltage of the rotating electric machine while it is in operation and suppress its effects.

[0004] In view of this, a technique has been proposed for estimating the amount of eccentricity by detecting the circulating current flowing through the parallel connections in an electric motor to which a magnetic bearing system is applied (see, for example, Patent Document 1). Also, a technique has been proposed for estimating the amount of eccentricity in a bearingless motor by detecting a three-phase induced voltage using a position control winding (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2015 / 019463 (paragraphs 0024-0027, Figure 2) [Patent Document 2] JP-A-11-142104 (paragraphs 0042-0045, Figures 1- Summary of the Invention [Problem to be solved by the invention]

[0006] However, in order to detect the circulating current flowing through the parallel connections, equipment such as a current sensor for detecting the circulating current is necessary, and when this technology is used for eccentricity inspection during the manufacturing process, there is a problem that the inspection device becomes large. In addition, equipment such as a current load is also required to detect the three-phase induced voltage. Therefore, when this technology is used for eccentricity inspection during the manufacturing process, there is a problem that the inspection device becomes large. In addition, when these technologies are applied to the drive system of a rotating electric machine, there is a problem that additional equipment is required, leading to a large system.

[0007] The present application discloses technology for solving the above-mentioned problems, and aims to provide a magnetic gap length estimation device, a magnetic gap length estimation method, a driving device for a rotating electric machine, or a magnetic gap length estimation method that can estimate a magnetic gap length without requiring additional equipment and suppress vibrations and noise caused by fluctuations in the magnetic gap length. [Means for solving the problem]

[0008] The magnetic gap length estimation device disclosed in the present application is characterized by including a voltage acquisition unit that acquires a line-to-line induced voltage induced in a connection between a rotating electric machine having multiple groups of coils when multiple phase coils are grouped together and an inverter that drives the rotating electric machine, an estimation information creation unit that creates estimation information for estimating a magnetic gap length from a waveform of the line-to-line induced voltage when the rotating electric machine is rotated in an unloaded state, and an instantaneous gap length estimation unit that estimates the instantaneous magnetic gap length from an instantaneous value of the line-to-line induced voltage and the estimation information.

[0009] The magnetic gap length estimation method disclosed in the present application is characterized by including a step of rotating a rotating electric machine having multiple groups of coils, where each group includes multiple phase coils, at a constant rotation speed under an unloaded state for at least one revolution, acquiring a waveform of a line-to-line induced voltage induced in connections of the rotating electric machine and an inverter that drives the rotating electric machine, and creating estimation information for estimating a magnetic gap length, and an instantaneous magnetic gap length estimation step of estimating the instantaneous magnetic gap length from an instantaneous value of the line-to-line induced voltage and the estimation information. Effect of the Invention

[0010] According to the magnetic gap length estimation device or magnetic gap length estimation method disclosed in the present application, the magnetic gap length of the rotating electric machine is estimated based on the results of comparing the line-to-line induced voltage of the connection between the inverter and the rotating electric machine with estimated information based on the characteristics of the rotating electric machine. Therefore, the magnetic gap length can be estimated without requiring additional equipment such as a current sensor or a current load, and vibrations and noise caused by fluctuations in the magnetic gap length can be suppressed. [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram for explaining a configuration of a magnetic gap length estimation device according to a first embodiment. [Diagram 2] 2 is a block diagram for explaining a configuration of a magnetic gap length estimation unit of the magnetic gap length estimation device according to the first embodiment. FIG. [Diagram 3] 1 is a plan view showing a configuration of a stator of a rotating electric machine that is an object to be measured by a magnetic gap length estimation device according to a first embodiment. [Figure 4] 1 is a connection diagram of a stator of a rotating electric machine that is an object to be measured by a magnetic gap length estimation device according to a first embodiment. [Diagram 5] 1 is a schematic diagram showing a state in which dynamic eccentricity occurs in a rotating electric machine that is a measurement target of a magnetic gap length estimation device according to a first embodiment. FIG. [Figure 6] 4 is a flowchart for explaining all steps in a magnetic gap length estimation method according to the first embodiment. [Figure 7]4 is a flowchart for explaining a pre-processing phase in the magnetic gap length estimation method according to the first embodiment. [Figure 8] 4 is a flowchart for explaining a detection phase in the magnetic gap length estimation method according to the first embodiment. [Figure 9] 9A and 9B are diagrams in the form of waveform diagrams and bar graphs showing amplitudes for each order by Fourier transform, to explain the operation of the process of extracting the fundamental wave component and L±P-order harmonic components of the line voltage in the magnetic gap length estimation method according to the first embodiment. [Figure 10] 4 is a line graph showing the relationship between dynamic eccentricity and harmonic components, for explaining the operation of a step of estimating the amount of variation in magnetic gap length in the magnetic gap length estimation method according to the first embodiment. FIG. [Figure 11] 4 is a line graph diagram for explaining an operation of estimating a displacement direction with respect to a magnetic pole position of a rotor in the magnetic gap length estimation method according to the first embodiment. FIG. [Figure 12] 12A and 12B are diagrams showing waveforms of line voltages between different phases in the same group and Lissajous curves, for explaining the operation of the step of creating a Lissajous curve in the magnetic gap length estimation method according to the first embodiment. [Figure 13] 13A and 13B are diagrams showing waveforms of line voltages between different groups and the same phase and a Lissajous curve, for explaining the operation of the step of creating a Lissajous curve in the magnetic gap length estimation method according to the first embodiment. [Figure 14] 14A and 14B are diagrams in the form of line graphs showing the relationship between the absolute displacement direction and the angle of the Lissajous curve, and diagrams showing the trajectory of the angle of the Lissajous curve with changes in the displacement direction, for explaining the operation of the process of creating a Lissajous curve in the magnetic gap length estimation method according to the first embodiment. [Figure 15] 4 is a plan view of a stator showing the configuration of another rotating electric machine that is the measurement target of the magnetic gap length estimation device according to the first embodiment. FIG. [Figure 16]FIG. 11 is a block diagram for illustrating a configuration of a driving device for a rotating electric machine and a rotating electric machine system according to a second embodiment. [Figure 17] FIG. 11 is a block diagram for explaining a configuration of a magnetic gap length estimation device according to a third embodiment. [Figure 18] 11 is a plan view showing a configuration of a stator of a rotating electric machine that is an object to be measured by a magnetic gap length estimation device according to a third embodiment. FIG. [Figure 19] FIG. 11 is a connection diagram of a stator of a rotating electric machine that is a measurement target of a magnetic gap length estimation device according to a third embodiment. [Figure 20] FIG. 13 is a block diagram for illustrating a configuration of a driving device for a rotating electric machine and a rotating electric machine system according to a fourth embodiment. [Figure 21] FIG. 13 is a block diagram for explaining the configuration of a magnetic gap length estimation device according to a fifth embodiment. [Figure 22] 13 is a plan view showing a configuration of a stator of a rotating electric machine that is an object to be measured by a magnetic gap length estimation device according to a fifth embodiment. FIG. [Diagram 23] 13 is a plan view of a stator showing the configuration of another rotating electric machine that is the measurement target of the magnetic gap length estimation device according to the fifth embodiment. FIG. [Figure 24] FIG. 13 is a block diagram for explaining the configuration of a driving device for a rotating electric machine and a rotating electric machine system according to a sixth embodiment. [Diagram 25] 3 is a block diagram showing an example of a hardware configuration of a magnetic gap length estimation device or a driving device for a rotating electric machine according to each embodiment; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a magnetic gap length estimation device, a magnetic gap length estimation method, a driving device for a rotating electric machine, and a magnetic gap estimation method according to embodiments of the present invention will be described in detail with reference to the drawings. Note that the same reference numerals in each drawing indicate the same or corresponding parts.

[0013] Embodiment 1 Fig. 1 to Fig. 4 are diagrams for explaining the configuration and operation of a magnetic gap length estimation device according to a first embodiment, Fig. 1 is a block diagram including a rotating electric machine and an inverter, which are objects to be measured, for explaining the configuration of the magnetic gap length estimation device, Fig. 2 is a block diagram for explaining the configuration of a magnetic gap length estimation unit of the magnetic gap length estimation device, Fig. 3 is a plan view perpendicular to an axis showing the configuration of a stator of a rotating electric machine, which is an object to be measured by the magnetic gap length estimation device, and Fig. 4 is a connection diagram of the stator of the rotating electric machine corresponding to Fig. 3.

[0014] <Magnetic gap length estimation device> 1, the magnetic gap length estimation device 1 according to the first embodiment is a device for measuring a rotating electric machine 7 driven by a three-group three-phase inverter 8 composed of three inverters 8a to 8c. The device estimates the gap length based on the line voltages of the connections 9 between the inverter 8 and the rotating electric machine 7 without using additional equipment such as a current load. For this reason, the device includes a voltage acquisition unit 2 for acquiring the line voltages of the nine connections 9, an estimation information creation unit 3 for creating estimation information for estimating the magnetic gap length, and an instantaneous gap length estimation unit 4 for estimating the instantaneous magnetic gap length based on the line voltages acquired while the rotating electric machine 7 is being driven and the estimation information.

[0015] The instantaneous gap length estimation unit 4 estimates the instantaneous magnetic gap length during operation based on the line voltage acquired by the voltage acquisition unit 2 while the rotating electric machine 7 is in operation and the estimation information created in advance by the estimation information creation unit 3. The instantaneous gap length estimation unit 4 has an external output terminal 4t for outputting information on the estimated magnetic gap length, and for example, by connecting an external monitor to the external output terminal 4t, the state of the magnetic gap can be visualized.

[0016] The estimation information creation unit 3 is roughly divided into an information acquisition and storage unit for acquiring and storing information necessary for estimation, a calculation unit for analyzing the acquired and stored information to calculate the gap length, and an output unit for storing and outputting the calculation results. As shown in Fig. 2, the information acquisition and storage unit includes a memory unit 31 for saving data transmitted from the voltage acquisition unit 2, a basic characteristic storage unit 32 for storing basic characteristics of the rotating electric machine 7, and an estimation reference storage unit 33 for storing estimation reference data for estimating the magnetic gap length.

[0017] The calculation section includes an analysis section 34 that extracts the amplitude and phase of the fundamental wave component and L±P order harmonic components of the line-to-line induced voltage based on the data transmitted from the memory section 31, and an estimated information calculation section 35 that calculates estimated information based on the data extracted by the analysis section 34. The output section includes a calculation result storage section 36 that stores the estimated information estimated by the estimated information calculation section 35 and outputs it to the instantaneous gap length estimation section 4 as necessary.

[0018] The basic characteristic storage unit 32 stores the dimensions, standard rotation speed, and other specifications of the rotating electric machine 7 to be measured. The estimation reference storage unit 33 stores estimation reference data required to estimate the magnetic gap length. The estimation reference data is, for example, the relationship between the line-to-line no-load induced voltage of the rotating electric machine 7 to be measured and the magnetic gap length. This estimation reference data is obtained in advance by measurement or calculated by theoretical calculation. Here, the line-to-line no-load induced voltage is the voltage induced between the coils when the rotating electric machine 7 is rotated at the rated rotation speed in a no-load state where no current is applied to the armature.

[0019] The analysis unit 34 includes a spectrum analysis unit 341 that converts the data acquired from the memory unit 31 into amplitude and phase information for each frequency, and a frequency analysis unit 342 that extracts the amplitude and phase of the fundamental component and L±P-order harmonic components of the line-to-line induced voltage from the amplitude and phase for each frequency. The spectrum analysis unit 341 converts the data into amplitude and phase information using, for example, a Fast Fourier Transform (FFT) algorithm, but another algorithm may be used as long as it can realize a similar spectrum analysis.

[0020] <Basic structure of rotating electrical machines> Before describing the operation of the magnetic gap length estimation device 1 according to this embodiment, the rotating electric machine 7 to be measured will be described. As shown in Fig. 3, the rotating electric machine 7 has a 6-pole, 36-slot stator 71 assuming a 3-group, 3-phase inverter drive. The stator 71 is configured such that coils not assigned with a code are wound independently in three groups, group 1, group 2, and group 3, and each group is arranged separately in the circumferential direction of the stator 71 with a mechanical angle phase difference of 360 / 3 = 120°.

[0021] In addition, in Fig. 3, the direction of current flowing in each coil is indicated by two types of symbols. A symbol with a cross (×) inside a circle (○) indicates the direction in which current flows from the front to the back of the page, and a symbol with a black circle (●) inside a circle indicates the direction in which current flows from the back to the front of the page. Note that the rotor 72 (Fig. 5) is not shown in Fig. 3.

[0022] The rotating electric machine 7, which is the measurement target of the magnetic gap length estimation device 1 according to the first embodiment, has a stator 71 with a distributed winding structure in which coils are arranged across several slots. Each of the three groups is composed of three phases, U, V, and W phases, and each phase is further composed of two coils. For example, U1 indicating the coil of the U phase in group 1 has two coils U11 and U12.

[0023] In Figure 3, the arrows indicate the winding direction of each coil in group 1. The winding direction of each coil in groups 2 and 3 is the same as that of group 1. The coils in each group are wound continuously in the circumferential direction in the order of U, W, and V phases. For example, in group 1, the coils are arranged counterclockwise in the order U11, U12, W11, W12, V11, and V12. Groups 2 and 3 have a similar arrangement.

[0024] That is, when M and K are natural numbers and N is a natural number of 2 or more, the k-th coil in m groups and n phases in a rotating electric machine 7 configured with M groups and N phases, each of which has K coils, is expressed as C(m, n, k). Note that in this application, natural numbers are treated as integers of 1 or more. In this case, the rotating electric machine 7 to be measured satisfies 1≦m≦M, 1≦n≦N, 1≦k≦K, and M=3, N=3, and K=2.

[0025] The coils of the rotating electric machine 7 are arranged counterclockwise from group 1 in ascending order of k, ascending order of n, and ascending order of m. Specifically, they are arranged in the following order starting from C(1,1,1), C(1,1,2), C(1,2,1), C(1,2,2), C(1,3,1), C(1,3,2), C(2,1,1), C(2,1,2), C(2,2,1), C(2,2,2), C(2,3,1), C(2,3,2), C(3,1,1), C(3,1,2), C(3,2,1), C(3,2,2), C(3,3,1), and C(3,3,2).

[0026] When the coils of each group and each phase are arranged continuously along the circumferential direction in this way, the difference in the amplitude of the voltage waveform of each phase due to the imbalance in the magnetic gap length caused by static eccentricity and dynamic eccentricity becomes larger than when they are arranged discontinuously. When the difference in amplitude becomes larger, the L±P-th harmonic components of each line voltage used to estimate the magnetic gap length also become larger, making it possible to improve the accuracy of estimating the magnetic gap length. As a result, the amount of current applied to each group can be adjusted according to the magnetic gap length that varies with time, making it possible to more efficiently achieve control that suppresses vibrations caused by dynamic eccentricity.

[0027] The rotating electric machine 7 described in FIG. 3 is connected as shown in FIG. 4. The coils of each group are configured with an independent Y-connection, and the coils of each phase are connected in series. With such a circuit configuration, the difference in amplitude of the voltage waveform between the phases becomes larger, and for the same reason as above, the estimation accuracy of the magnetic gap length can be improved. In addition, since the coils of each group are Y-connected and the coils of each phase are connected in series, no circulating current is generated. Therefore, there is no influence of the induced voltage caused by the circulating current, and the detection accuracy of the line voltage can be improved.

[0028] <Method for estimating magnetic gap length> On the premise of the above-mentioned configuration, the operation of the magnetic gap length estimation device 1 according to the first embodiment, that is, the magnetic gap length estimation method, will be described with reference to Fig. 5 to Fig. 14A and Fig. 14B. Fig. 5 is a schematic diagram corresponding to Fig. 3 showing a state in which dynamic eccentricity occurs in a rotating electric machine that is the measurement target of the magnetic gap length estimation device, Fig. 6 is a flowchart for explaining the overall process in the magnetic gap length estimation method, Fig. 7 is a flowchart for explaining the pre-processing phase out of the two phases constituting the magnetic gap length estimation method, and Fig. 8 is a flowchart for explaining the remaining detection phase.

[0029] Fig. 9A and Fig. 9B are diagrams for explaining the operation of the process of extracting the fundamental wave component and L±P-order harmonic components of the line voltage, with Fig. 9A being a waveform diagram of the line voltage and Fig. 9B being a bar graph diagram showing the amplitude for each order by Fourier transform. Fig. 10 is a line graph diagram showing the relationship between the amount of dynamic eccentricity and the harmonic components of the line voltage to explain the operation of the process of estimating the amount of fluctuation in the magnetic gap length, and Fig. 11 is a line graph diagram showing the relationship between the third-order component, fourth-order component, and the difference between the third-order component and fourth-order component of the line voltage with respect to the displacement direction to explain the operation of estimating the displacement direction with respect to the magnetic pole position of the rotor.

[0030] Fig. 12A and Fig. 12B are for explaining the operation of the process of creating a Lissajous curve, Fig. 12A is a waveform diagram of line voltages between the same group and different phases, and Fig. 12B is a diagram showing a Lissajous curve created by arranging the waveform of Fig. 12A on the X and Y coordinates in the rotation angle. Meanwhile, Fig. 13A and Fig. 13B are also for explaining the operation of the process of creating a Lissajous curve, Fig. 13A is a waveform diagram of line voltages between the different group and same phases, and Fig. 13B is a diagram showing a Lissajous curve created by arranging the waveform of Fig. 13A on the X and Y coordinates in the rotation angle.

[0031] 14A and 14B are also intended to explain the operation of the process of creating a Lissajous curve, with FIG. 14A being a line graph showing the relationship between the absolute displacement direction and rotation angle due to dynamic eccentricity and the angle of the Lissajous curve, and FIG. 14B being a diagram showing the trajectory of the angle of the Lissajous curve as the displacement direction changes.

[0032] 5, it is assumed that the center of rotation C2r of the rotor 72 coincides with the center C1s of the inner diameter of the stator 71, while the geometric center C2s of the rotor 72 is shifted in the direction of 180° when the circumferential boundary position between group 1 and group 2 is set to 0°. It is also assumed that the position of each of the six-pole permanent magnets 72m is such that the circumferential center position (magnetic pole position) of the permanent magnet 72m is located at a position of 180°.

[0033] In this case, the magnetic gap between the stator 71 and the rotor 72 is non-uniform in the circumferential direction, and the magnetic gap length varies with time as the rotor 72 rotates. A method for estimating the instantaneous magnetic gap length for the rotating electric machine 7 in such a state will be described. As shown in the flowchart of Fig. 6, the method for estimating the magnetic gap length according to the first embodiment is roughly divided into two phases, a pre-processing phase Ph1 and a detection phase Ph2.

[0034] In the pre-processing phase Ph1, the rotating electric machine 7 is rotated at least once to generate information to be stored in the estimated information generating unit 3. The rotation at this time is in a no-load state where no current is passed through the rotating electric machine 7. This makes it possible to construct an inspection facility that does not require the addition of a current sensor in the production line, and improves the estimation accuracy of the magnetic gap length by suppressing the effects of harmonic noise and the like caused by the current load.

[0035] In the next detection phase Ph2, an estimation process is performed for the instantaneous magnetic gap length in a driving state in which the rotating electric machine 7 is continuously rotated with or without a current load. The first phase, or pre-processing phase Ph1, is completed from Start 1 to End 1, and then the second phase, or detection phase Ph2, is completed from Start 2 to End 2.

[0036] In addition, in the case where the purpose is to obtain the dynamic eccentricity amount of each sample in the production line, the estimation may be completed up to the pre-processing phase Ph1. Also, if the pre-processing phase Ph1 has been completed and the estimation information is stored in the estimation information creating unit 3, the pre-processing phase Ph1 may be omitted and only the detection phase Ph2 in which the instantaneous magnetic gap length is estimated in the normal driving state may be executed from the beginning.

[0037] Next, as a detailed operation of each phase, the pre-processing phase will be described first. The pre-processing phase Ph1 executed by the estimation information creation unit 3 includes steps S11 to S16 as shown in the flowchart of FIG. 7. First, line-to-line induced voltages between same-group different phases and different-group in-phases are acquired at least at two locations each (step S11). Specifically, for example, the voltage acquisition unit 2 of the magnetic gap length estimation device 1 acquires line voltages between U2-V2 and V2-W2 as same-group different phases and between U1-U2 and U1-U3 as different-group in-phases, and the memory unit 31 receives and stores the acquired data.

[0038] In this embodiment, an example is shown in which the above-mentioned line spaces are obtained, but other phase combinations may also be used, such as obtaining two locations U1-U2 and V1-V2 as different group in-phase spaces.

[0039] Next, in the analysis unit 34, the spectrum analysis unit 341 performs spectrum analysis on the line voltage data stored in the memory unit 31 (step S12). Specifically, the spectrum analysis unit 341 applies a fast Fourier transform algorithm to the line voltage data to convert it into amplitude and phase information for each frequency. Furthermore, the frequency analysis unit 342 extracts the amplitude and phase of the fundamental wave component and L±P order harmonic components of each line voltage from the amplitude and phase information for each frequency (step S13).

[0040] Here, the relationship between the fundamental wave components and L±P-order harmonic components of the phase voltage and line voltage and the magnetic gap length will be described. In this embodiment, since the measurement target is a rotating electric machine 7 with 6 poles and 36 slots, the number of pole pairs L=3 (=6 / 2). Furthermore, the permeance (=the reciprocal of the magnetic resistance) of the magnetic gap includes a 1st order component caused by dynamic eccentricity in addition to the 0th order component which is the main component when one mechanical revolution of the magnetic gap is used as a reference. Furthermore, considering that the coil interlinkage magnetic flux proportional to the line induced voltage is calculated by the product of the permeance of the magnetic gap and the magnetomotive force of the rotor 72, the order of the main component included in the magnetomotive force of the rotor 72 is the 3rd order, which is equal to the number of pole pairs L of the rotor 72.

[0041] From these, the product-sum formula of trigonometric functions shows that the induced voltage waveform of the phase is a waveform that is the sum of a fundamental wave component of order equal to the number of pole pairs L, which is third order (=3±0) per mechanical revolution of rotor 72, as well as fourth order (=3+1) and second order (=3-1) components resulting from permeance fluctuations due to dynamic eccentricity. In the first embodiment, dynamic eccentricity is assumed, so an example is shown in which the order P is 1, but in other cases, such as when the roundness of rotor 72 has deteriorated and the rotor has been deformed into an elliptical shape, the permeance includes a second order component, so the order P=2.

[0042] Furthermore, when harmonic components are included in the permeance per revolution of the rotor 72, they similarly occur when the order P is 3 or more, and it is self-evident that 3±P order components occur. Also, although an example in which the number of pole pairs L is 3 is shown in this embodiment, it is self-evident that L±P order components also occur in rotating electric machines 7 having other numbers of pole pairs L.

[0043] Since the line voltage waveform is the difference between the phase voltage waveforms of the two selected phases, there is a phase difference of 120° electrical angle between the selected phases in the same group / different phase case, and therefore the third-order component, which is the fundamental wave component described above, and the second-order and fourth-order components caused by dynamic eccentricity are included without being cancelled out. On the other hand, in the different group / in-phase case, the phase between the selected phases is the same or close to a value, so the third-order component, which is the fundamental wave component, is cancelled out and the second-order or fourth-order components caused by dynamic eccentricity are included as the main components in the line voltage waveform.

[0044] For example, we will explain the line-to-line no-load induced voltage waveforms of different groups and in-phase (U1U3) when rotor 72 is rotated once in mechanical angle, and a comparison by order of the amplitude of the Fourier transform results. Here, we show the results of the line-to-line no-load induced voltage waveforms (voltage in PU units) when the dynamic eccentricity amount (= dynamic eccentricity rate) relative to the magnetic gap length is 0% (Re1: dashed line), 20% (Re2: solid line), and 40% (Re3: dotted line).

[0045] As shown in Fig. 9A, compared to when there is no dynamic eccentricity (Re1), as the dynamic eccentricity increases (Re2, Re3), the line voltage increases. Furthermore, as shown in Fig. 9B, the main component is the fourth-order component, and while there is a significant increase in proportion to the dynamic eccentricity ratio, it is clear that the third-order component, which is the fundamental wave component, is not included.

[0046] This will be considered based on the winding structure of the rotating electric machine 7, which is the measurement target of the present embodiment 1 and is described with reference to Fig. 3. In this example, the electrical angle is three times the mechanical angle for each pole pair. Therefore, when the circumferential boundary between group 1 and group 3 is set to 0°, the electrical center positions of the phase coils of each phase in each group are 120°, 240°, 360°, 120°, 240°, 360°, 120°, 240°, and 360° in electrical angle for the U, V, and W phases of groups 1, 2, and 3, respectively.

[0047] Since the electrical center positions of both the U1 phase and the U3 phase are the same at 120°, it can be seen that the phases of the fundamental wave components contained in the phase voltages are the same and are cancelled out in the line voltage. If the electrical phase difference between the circumferential positions of the coils in the different groups and the same phase is 0° as in this embodiment, it is self-evident that the fundamental wave components are cancelled out and a line voltage waveform containing a component due to dynamic eccentricity as the main component is obtained. By making the main component of the line voltage waveform the component due to dynamic eccentricity, it is possible to improve the estimation accuracy of the instantaneous magnetic gap length, and the reason for this will be explained in detail later.

[0048] Next, the estimated information calculation unit 35 estimates the magnetic gap length using the fourth harmonic component of the line voltage. For this purpose, the estimated information calculation unit 35 estimates the absolute value of the amount of variation in the magnetic gap length due to dynamic eccentricity (step S14). The amount of dynamic eccentricity and the amplitude of the fourth harmonic component of the line voltage are roughly proportional to each other as shown in FIG. 10. This relationship is compiled into a database in advance by theoretical calculation, simulation, experiment, etc., and stored in the estimation reference storage unit 33. This relationship may be stored as a formula or a numerical value table.

[0049] In step S14, the estimation information calculation unit 35 estimates the absolute value of the amount of variation in the magnetic gap length due to dynamic eccentricity, using the relationship between the amount of dynamic eccentricity stored in the estimation reference storage unit 33 and the amplitude of the fourth harmonic component of the line voltage.

[0050] The estimated information calculation unit 35 also estimates the relative displacement direction with respect to the magnetic pole position of the rotor using phase information of the third-order and fourth-order components of the line voltage (step S15). Here, changes in the third-order component, fourth-order component, and difference between the third-order and fourth-order components of the line voltage when the relative displacement direction with respect to the magnetic pole position of the rotor 72 changes within a range of 180° to 300° based on the angle shown in Fig. 5 will be described with reference to Fig. 11. In Fig. 11, the phase of the third-order component of the line voltage between the same group and different phases is δ3 (▲, dashed line), the phase of the fourth-order component of the line voltage between the different group and same phases is δ4 (■, dotted line), and the difference therebetween is δ34 (=δ3-δ4: ●, solid line).

[0051] As shown in Figure 11, the phase (δ3) of the third-order component, which is the fundamental wave component, does not change in the direction of relative displacement with respect to the magnetic pole, while the phase (δ4) of the fourth-order component varies linearly. In other words, the phase (δ3) of the third-order component included in the line voltage waveform between the same group and different phases and the phase (δ4) of the fourth-order component included in the line voltage waveform between the different group and same phase are extracted, and the difference (δ34) between them is calculated.

[0052] Meanwhile, information on the relationship between δ3, δ4, and δ34 with respect to the assumed displacement direction is compiled into a database based on theoretical calculations, simulations, experiments, etc., and stored in the estimation reference storage unit 33. By comparing the obtained results with the stored information, it is possible to estimate the relative displacement direction with respect to the magnetic pole position of the rotor 72. In other words, if information on the magnetic pole position of the rotor 72 is obtained, it is possible to estimate the absolute displacement direction due to dynamic eccentricity.

[0053] To formulate this, if the rotation angle when the magnetic pole center is set as the reference angle of 0° is defined as θ, and the relative displacement direction with respect to the magnetic pole position of the rotor 72 calculated from the above-mentioned relationship is defined as α, the absolute displacement direction φ of the magnetic gap length due to dynamic eccentricity can be calculated by equation (1). φ=θ+α (1) In this embodiment, the absolute displacement direction of the magnetic gap length due to dynamic eccentricity is set to the position where the magnetic gap is smallest.

[0054] Next, using the line voltage waveforms between same-group different phases and between different-group in-phases acquired in step S11, Lissajous curves are created (step S16). As shown in Figures 12A, 12B, 13A, and 13B, Lissajous curves that rotate three times and four times per 360° rotation angle can be drawn. Note that in Figure 12A, U2V2 (solid line) and V2W2 (dotted line) are shown as line voltage waveforms between same-group different phases, and in Figure 13A, U1U2 (solid line) and U1U3 (dotted line) are shown as line voltage waveforms between different-group in-phases.

[0055] If we define the angles θ3 and θ4 of the Lissajous curve with respect to the rotation angle θ, we can see that θ3 changes in three periods and θ4 changes in four periods while the rotation angle θ changes from 0° to 360°. Here, we will use Figures 14A and 14B to consider the relationship in which θ3 and θ4 change with the absolute displacement direction φ due to dynamic eccentricity, and the trajectory when φ changes from 0° to 360° with θ3 on the vertical axis and θ4 on the horizontal axis. In Figure 14A, θ3 is shown by a solid line and θ4 by a dotted line.

[0056] 14B, since there is no overlap in the trajectories, it can be seen that θ3 and θ4 are uniquely determined for the absolute displacement direction φ due to dynamic eccentricity. In other words, by extracting θ3 and θ4 from the acquired line voltage waveform, the absolute displacement direction φ due to dynamic eccentricity can be uniquely determined.

[0057] Since θ3 and θ4 can be calculated from the instantaneous value of the line voltage waveform, it is possible to estimate the absolute displacement direction φ due to the instantaneous dynamic eccentricity by using the above-mentioned trajectory relationship. This will be described in detail using the flowchart of the detection phase shown in Figure 8.

[0058] That is, instantaneous values ​​of line voltages at two locations each between same group different phases and between different group common phases during continuous operation are measured (acquired) (step S21). The two instantaneous values ​​of the line voltages between same group different phases acquired at two locations are arranged on the X and Y coordinates, respectively, and their arctangents are calculated as θ3, and the two instantaneous values ​​of the line voltages between different group common phases acquired at two locations are arranged on the X and Y coordinates, respectively, and their arctangents are calculated as θ4 (step S22).

[0059] The calculated θ3 and θ4 are compared with the relationship of the Lissajous curves shown in Fig. 14B, for example, created in step S16 of the pre-processing phase Ph1 (step S23). As described above, θ3 and θ4 are uniquely determined for the absolute displacement direction φ due to dynamic decentering, so that the absolute displacement direction φ due to dynamic decentering at that moment can be estimated from the comparison result (step S24).

[0060] 12B, 13B, and 14B show an example in which the rotation angle θ of rotor 72 is 120°. In this embodiment, the relative displacement direction α of rotor 72 with respect to the magnetic poles is 180°, and the absolute displacement direction φ due to dynamic eccentricity at an instant is 360° (=120°+180°).

[0061] In other words, by obtaining the amount of dynamic eccentricity estimated in the pre-processing phase Ph1 and the absolute direction of displacement due to dynamic eccentricity at an instant estimated in the detection phase Ph2, it is possible to visualize and monitor the instantaneous state of the magnetic gap length.

[0062] As described above, the magnetic gap length estimation device 1 of the present embodiment 1 includes a voltage acquisition unit 2 that acquires a line voltage, an estimation information creation unit 3 that creates information for estimating the instantaneous magnetic gap length of the rotating electric machine 7, and an instantaneous gap length estimation unit 4 that estimates the instantaneous magnetic gap length by comparing the information with the instantaneous line voltage.

[0063] The estimated information creating unit 3 includes a spectrum analyzing unit 341 that converts the line voltage into an amplitude and phase for each frequency, a frequency analyzing unit 342 that extracts the amplitude and phase of the fundamental wave component and L±P order harmonic components of the line voltage from the amplitude and phase for each frequency, and an estimated information calculating unit 35 that calculates estimated information for estimating the magnetic gap length of the rotating electric machine from the amplitude and phase of the fundamental wave component and L±P order harmonic components of the line voltage. Therefore, the magnetic gap length estimation device 1 of the present embodiment 1 does not require additional equipment such as a current sensor and a current load, and does not require voltage measurement at the neutral point of the connection.

[0064] In the above-mentioned first embodiment, an example has been shown in which the fourth-order component is focused on as a feature amount of dynamic eccentricity, but the second-order component may be the main component depending on the structures of rotor 72 and stator 71, and other order components may be focused on. Furthermore, with regard to the number of pole pairs as well, in the case of dynamic eccentricity when a structure of L pole pairs is adopted instead of 3 pole pairs, it is self-evident that one of the L±1 order components will be the main component, and it is sufficient to focus on the L±1 order components that are the main components depending on the structure.

[0065] As described above, even if the permeance fluctuation is second or higher due to a factor other than dynamic eccentricity, the instantaneous magnetic gap length can be estimated by the same method, so it is sufficient to focus on the L±P order components that are the main components depending on the structure. In addition, in this embodiment, an example of dynamic eccentricity in which the geometric center is displaced in the direction of the magnetic pole center of the rotor 72 with the rotation center as the reference has been shown. The magnetic gap length estimation device 1 of this embodiment can achieve the same effect even when dynamic eccentricity occurs in other directions.

[0066] 1 illustrates an example in which the voltage acquisition unit 2 of the magnetic gap length estimation device 1 is connected to each of the connections 9 (9 wires) connecting the 3-group 3-phase windings and the rotating electric machine 7. However, the magnetic gap length estimation device 1 according to the first embodiment can create a Lissajous curve and estimate the instantaneous magnetic gap length by acquiring a line voltage between different groups and in phase (different groups in phase) at least at one location in addition to a line voltage between same groups in phase in addition to a line voltage between same groups in phase. In other words, it is sufficient to acquire a minimum line voltage waveform that can create a Lissajous curve even if all nine connections 9 are not connected to the voltage acquisition unit 2.

[0067] Variations. In this modification, an example will be described in which a rotating electric machine having a rotor with a different number of slots is used as the measurement target, instead of the rotating electric machine having a rotor with 6 poles and 36 slots described in Fig. 3. Fig. 15 is a plan view perpendicular to an axis showing the configuration of the stator of a rotating electric machine that is the measurement target of a magnetic gap length estimation device according to this modification. Note that in Fig. 15, as in Fig. 3, the direction of current flowing through each coil is indicated by two types of symbols, and the rotor is not drawn.

[0068] The rotating electric machine 7 that is the measurement target of the magnetic gap length estimation device 1 according to this modified example has a 6-pole, 9-slot configuration with a coil wound around one tooth using concentrated winding, as shown in Fig. 15. When the m-group, n-phase, k-th coil of this rotating electric machine 7 is expressed as C(m, n, k), 1≦m≦M, 1≦n≦N, 1≦k≦K, and M=3, N=3, and K=1.

[0069] The coils of the rotating electric machine 7 are arranged counterclockwise from group 1 in ascending order of k, ascending order of n, and ascending order of m. Specifically, they are arranged in the following order: C(1,1,1), C(1,2,1), C(1,3,1), C(2,1,1), C(2,2,1), C(2,3,1), C(3,1,1), C(3,2,1), C(3,3,1).

[0070] Even in such a concentrated winding rotating electric machine 7, the coils of each group and each phase are continuously arranged in the circumferential direction, so that the difference in amplitude of the voltage waveform between phases due to the imbalance in the magnetic gap length caused by eccentricity becomes large. Therefore, the second or fourth harmonic components contained in the line voltage also become large, so that the estimation accuracy of the magnetic gap length can be further improved.

[0071] In the magnetic gap length estimation device 1 according to the first embodiment or its modified example, the line voltage between the coil phases belonging to different groups is measured. The coils in each group are configured with an independent Y-connection. Therefore, an offset component of the potential difference caused by the coils in each group being electrically independent may be included in the line voltage between two phases belonging to different groups. In order to remove this offset component, the neutral points of the Y-connection to the coils in each group may be electrically connected to each other.

[0072] Embodiment 2 In the first embodiment, a magnetic gap length estimation device that estimates the magnetic gap length of a rotating electric machine has been described. In the second embodiment, a driving device for a rotating electric machine and a rotating electric machine system that include the magnetic gap length estimation device described in the first embodiment will be described. Fig. 16 is a block diagram for explaining the configuration of the driving device for a rotating electric machine and the rotating electric machine system according to the second embodiment. The configuration and operation of the magnetic gap length estimation device itself are similar to those of the first embodiment, so a description of similar parts will be omitted.

[0073] 16, a driving device 10 of a rotating electric machine in the second embodiment has the magnetic gap length estimation device 1 described in the first embodiment, and a control parameter calculation unit 5 that receives an output from the instantaneous gap length estimation unit 4 and sends a control parameter to an inverter 8. The rotating electric machine 7, the inverter 8, and the driving device 10 of the rotating electric machine form a rotating electric machine system 100. The control parameter calculation unit 5 sends a control parameter for adjusting a current input value to each group of the rotating electric machine 7 to each of the three inverters 8a to 8c, based on the magnetic gap length estimated by the magnetic gap length estimation device 1.

[0074] That is, the magnetic gap length estimation device 1 in the drive device 10 has a relationship in which the external output terminal 4t of the instantaneous gap length estimation unit 4 described in Fig. 1 is connected to the control parameter calculation unit 5. On the other hand, the control parameter calculation unit 5 has an external output terminal 5t, and the control parameters can be visualized, for example, by connecting an external monitor to this external output terminal 5t. Of course, information regarding the state of the magnetic gap obtained from the instantaneous gap length estimation unit 4 may also be output from the external output terminal 5t and visualized.

[0075] Based on the above configuration, the control operation of the drive device 10 will be described. For example, it is assumed that the rotating electric machine 7 has dynamic eccentricity in which the geometric center is displaced toward the magnetic pole center of the rotor 72 with respect to the rotation center as described in the first embodiment. In this situation, it is assumed that the detection phase Ph2 in the no-load state is also completed using the estimated information obtained in the pre-processing phase Ph1 in which the rotating electric machine 7 is rotated in the no-load state as described in the first embodiment. In other words, it is assumed that the variation characteristic of the magnetic gap length according to the rotation position of the rotor 72 is obtained.

[0076] In such a state, when the rotating electric machine 7 is rotated under a load, the waveform obtained will differ from that in the no-load state, but for a multi-group, multi-phase rotating electric machine 7, the rotational position can be grasped from the output state of the inverter 8. Therefore, when the instantaneous rotor position is as shown in Fig. 5, the control parameter calculation unit 5 transmits control parameters to each inverter 8 based on the grasped rotational position so as to adjust the current input value as follows.

[0077] In the situation shown in Fig. 5, the magnetic gap length of group 3 becomes smaller than the magnetic gap length of groups 1 and 2, just as in the no-load state. Since this situation occurs in response to the rotational position, the current input value to the coils belonging to group 3 for that instantaneous time (rotational position) is set smaller than the current input value to the coils belonging to groups 1 and 2. As time passes, for a situation (rotational position) where the position where the magnetic gap length becomes smaller corresponds to a different group, the current value of that group is set smaller than the other groups.

[0078] In this way, the eccentricity state corresponding to the rotational position of the rotor 71 is grasped using the estimated information obtained in the pre-processing phase Ph1 and the inspection phase Ph2 in a no-load state using the estimated information. Then, the rotational position when the rotating electric machine 7 is actually driven can be grasped from the operating state of the inverter 8, so the setting of the current value for each group is changed according to the magnetic gap length that changes with the rotational position. By controlling in this way, it is possible to construct a rotating electric machine system 100 that can reduce vibration and noise caused by dynamic eccentricity.

[0079] In the second embodiment, too, an example is shown in which the voltage acquisition unit 2 of the magnetic gap length estimation device 1 is connected to each of the connections 9 (nine lines) connecting the three-group, three-phase windings and the rotating electric machine 7. However, similar to the first embodiment in which the magnetic gap length estimation device 1 is used alone, by acquiring at least one different-group and in-phase line voltage in addition to different-group and in-phase line voltages, the magnetic gap length estimation device 1 can create a Lissajous curve and estimate the instantaneous magnetic gap length. In other words, even if all nine connections 9 are not connected to the voltage acquisition unit 2, if a minimum line voltage waveform that can create a Lissajous curve can be acquired, the direction in which the magnetic gap length changes can be estimated and the control parameters can be calculated.

[0080] Embodiment 3 In the first and second embodiments, the case where a rotating electric machine driven by a three-group three-phase inverter is the measurement target has been described. In the third and fourth embodiments, the case where a rotating electric machine driven by a two-group three-phase inverter is the measurement target will be described.

[0081] Fig. 17 and Fig. 18 are for explaining the configuration and operation of a magnetic gap length estimation device according to a third embodiment, Fig. 17 is a block diagram including a rotating electric machine and an inverter that are objects to be measured and for explaining the configuration of the magnetic gap length estimation device, Fig. 18 is a plan view perpendicular to an axis showing the configuration of a stator of a rotating electric machine that is an object to be measured by the magnetic gap length estimation device, and Fig. 19 is a connection diagram of the stator of the rotating electric machine corresponding to Fig. 17. Note that Fig. 2 and Figs. 6 to 8 used in the first embodiment are used, and explanations of similar parts will be omitted.

[0082] As shown in Fig. 17, the magnetic gap length estimation device 1 according to the present embodiment 3 measures a rotating electric machine 7 driven by a two-group three-phase inverter 8. As in the first embodiment, the magnetic gap length estimation device 1 according to the present embodiment 3 also has a voltage acquisition unit 2, an estimation information creation unit 3, and an instantaneous gap length estimation unit 4. However, the voltage acquisition unit 2 acquires voltages of six connections 9 connecting two inverters 8a, 8b and the rotating electric machine 7. Also, the operation of the magnetic gap length estimation device 1 according to the present embodiment 3, that is, the method of estimating the magnetic gap length according to the present embodiment 3, is partially different from the operation described in the first embodiment.

[0083] The rotating electric machine 7 to be measured by the magnetic gap length estimation device 1 according to the third embodiment has a 10-pole, 12-slot configuration (number of pole pairs L=5) assumed to be driven by a two-group, three-phase inverter, as shown in Fig. 18. That is, in the third embodiment, the fifth-order component is used as the fundamental wave component for estimating the magnetic gap length, and when dynamic eccentricity is assumed, the fourth-order or sixth-order harmonic component is used as the feature amount thereof, but the other estimation methods for the magnetic gap length are the same as those in the first embodiment.

[0084] The coils of the stator 71 are configured as group 1 and group 2. In FIG. 18, the direction of the current flowing through each coil is indicated by two different symbols, as in FIG. 3. The stator 71 of this rotating electric machine 7 has a concentrated winding structure in which one coil is wound around one stator tooth. Both group 1 and group 2 are configured with three phases, U, V, and W, and each phase is further configured with two coils. For example, the coil of the U phase is made up of two coils U1 and U1, each of which has a different current direction. L The symbol " L " indicates that the winding directions of the concentrated winding coils are opposite to each other. The coils of this rotating electric machine 7 are U1, U2 in a counterclockwise direction. L , V1 L , V2, W1, W2 L , U1 L , U2, V1, V2 L , W1 L , W2, in that order.

[0085] As shown in FIG. 19, the coils of group 1 and group 2 are configured with a Y-type connection sharing a neutral point, and the coils of each phase are connected in parallel. In addition, group 1 and group 2 have a phase difference of 30° in electrical angle. By configuring the circuit in this way, it is possible to obtain the effect of the magnetic gap length estimation device 1 of the present application while minimizing the number of inverters used, and to reduce the cost of building the system. In addition, since there is a phase difference between the groups, the line voltage waveform between the different groups and the same phase includes a fundamental wave component, which increases the fluctuation of the Lissajous curve and reduces the detection accuracy of dynamic eccentricity, but it is possible to simultaneously suppress torque pulsation generated in the rotating electric machine 7.

[0086] In the third embodiment as well, an example is shown in which the voltage acquisition unit 2 of the magnetic gap length estimation device 1 is connected to each (six) of the connections 9 connecting the two groups of three-phase windings and the inverter 8. However, even if all six connections 9 are not connected to the voltage acquisition unit 2, if a minimum line voltage waveform capable of creating a Lissajous curve can be acquired, the direction in which the magnetic gap length is displaced can be estimated.

[0087] In addition, in the third embodiment, the neutral point is shared by group 1 and group 2, but when each group is independent, the same effect can be obtained, although disturbance due to the inclusion of offset components increases. In addition, in the third embodiment, the coils of each phase are connected in parallel, but by changing the coils of each phase to a series connection, it is possible to further improve the sensitivity to differences in magnetic gap length. In addition, in the third embodiment, the case where there is a phase difference of 30° in electrical angle between group 1 and group 2 is shown, but the connection may be such that the phase difference is 0°.

[0088] Embodiment 4 In the fourth embodiment, similarly to the relationship between the first and second embodiments, a driving device for a rotating electric machine and a rotating electric machine system including the magnetic gap length estimation device described in the third embodiment will be described. Fig. 20 is a block diagram for explaining the configuration of the driving device for a rotating electric machine and the rotating electric machine system according to the fourth embodiment. The configuration and operation of the magnetic gap length estimation device itself are similar to those of the third embodiment, and therefore a description of the similar parts will be omitted.

[0089] 20, a driving device 10 of a rotating electric machine in the fourth embodiment has the magnetic gap length estimation device 1 described in the third embodiment, and a control parameter calculation unit 5 that receives an output from the instantaneous gap length estimation unit 4 and sends a control parameter to an inverter 8. The rotating electric machine 7, the inverter 8, and the driving device 10 constitute a rotating electric machine system 100. The control parameter calculation unit 5 sends control parameters for adjusting a current input value to each group of the rotating electric machine 7 to each of the two inverters 8a, 8b, based on the magnetic gap length estimated by the magnetic gap length estimation device 1.

[0090] That is, also in the driving device 10 according to the fourth embodiment, the magnetic gap length estimation device 1 has an external output terminal 4t shown in FIG. 17 connected to the control parameter calculation unit 5. On the other hand, the control parameter calculation unit 5 has an external output terminal 5t, and for example, by connecting an external monitor to this external output terminal 5t, the control parameters can be visualized. Of course, information on the state of the magnetic gap obtained from the magnetic gap length estimation device 1 may also be output from the external output terminal 5t and visualized.

[0091] As with the above configuration and as described in the second embodiment, the detection phase Ph2 is performed based on the estimated information obtained in the pre-processing phase Ph1, and the variation characteristic of the magnetic gap length according to the rotational position of the rotor 72 is obtained. In other words, the control operation of the drive device 10 will be described on the premise that the variation characteristic of the magnetic gap length according to the rotational position of the rotor 72 has been obtained.

[0092] In the driving device 10 according to the fourth embodiment, for example, the current input values ​​to the groups 1 and 2 are made different and varied depending on the instantaneous rotor position, thereby generating harmonic components of the electromagnetic force in the magnetic gap. This makes it possible to suppress harmonic components of the electromagnetic force caused by permeance fluctuations accompanying time fluctuations such as dynamic eccentricity. By controlling in this way, it is possible to construct a rotating electric machine system 100 that can reduce vibrations and noise caused by variation factors such as time fluctuations such as dynamic eccentricity.

[0093] In the fourth embodiment, too, an example is shown in which the voltage acquisition unit 2 of the magnetic gap length estimation device 1 is connected to each of the connections 9 (six lines) connecting the two-group three-phase windings and the rotating electric machine 7. However, similarly to the third embodiment in which the magnetic gap length estimation device 1 is used alone, by acquiring at least one different-group and in-phase line voltage in addition to different-group and in-phase line voltages, the magnetic gap length estimation device 1 can create a Lissajous curve and estimate the instantaneous magnetic gap length. In other words, even if all six connections 9 are not connected to the voltage acquisition unit 2, if a minimum line voltage waveform capable of creating a Lissajous curve can be acquired, the direction in which the magnetic gap length changes can be estimated and the control parameters can be calculated.

[0094] Embodiment 5. In the fifth and sixth embodiments, a rotating electric machine driven by a four-group, five-phase inverter is described. Figs. 21 to 23 are for explaining the configuration and operation of the magnetic gap length estimation device according to the fifth embodiment, Fig. 21 is a block diagram including a rotating electric machine and an inverter as a measurement target for explaining the configuration of the magnetic gap length estimation device, Fig. 22 is a plan view perpendicular to the axis showing the configuration of a stator of a rotating electric machine as a measurement target of the magnetic gap length estimation device, and Fig. 23 is a plan view perpendicular to the axis of a stator showing the configuration of another rotating electric machine as a measurement target of the magnetic gap length estimation device. Note that Figs. 2 and 6 to 8 used in the first embodiment are also used in the fifth embodiment, and explanations of similar parts are omitted.

[0095] As shown in FIG. 21, the magnetic gap length estimation device 1 according to the present embodiment 5 measures a rotating electric machine 7 driven by a four-group five-phase inverter 8. The magnetic gap length estimation device 1 according to the present embodiment 5 also includes a voltage acquisition unit 2, an estimated information creation unit 3, and an instantaneous gap length estimation unit 4, similar to the first embodiment. However, the voltage acquisition unit 2 acquires line voltages of twenty connections 9 connecting the four inverters 8a to 8d and the rotating electric machine 7. The operation of the magnetic gap length estimation device 1 according to the present embodiment 5, that is, the method of estimating the magnetic gap length according to the present embodiment 5, is partially different from the operation described in the first embodiment.

[0096] The rotating electric machine 7 to be measured by the magnetic gap length estimation device 1 according to the fifth embodiment has an 8-pole, 80-slot configuration (number of pole pairs L=4) assumed to be driven by a 4-group, 5-phase inverter, as shown in Fig. 22. That is, in the fifth embodiment, the fourth-order component is used as the fundamental wave component for estimating the magnetic gap length, and when dynamic eccentricity is assumed, the third-order or fifth-order harmonic component is used as the feature amount thereof, but the other estimation methods for the magnetic gap length are the same as those in the first embodiment.

[0097] The coils of the stator 71 are configured as group 1 to group 4, and each group is arranged with a mechanical angle phase difference of 90° (=360 / 4). In addition, in Fig. 22, the direction of the current flowing through each coil is indicated by two types of symbols, as in Fig. 3. The stator 71 of this rotating electric machine 7 has a distributed winding structure in which coils are arranged across multiple slots. The coils of each group are configured with five phases, A, B, C, D, and E, and each phase is further configured with two coils.

[0098] For example, group 1 phase A has two coils A11 and A12. The coils in each group are wound circumferentially in the order of phases A, D, B, E, and C. For example, the coils in group 1 are arranged counterclockwise in the order of A11, A12, D11, D12, B11, B12, E11, E12, C11, and C12.

[0099] In other words, if the kth coil of m groups and n phases in a rotating electric machine consisting of M groups and N phases, with each phase consisting of K coils, is expressed as C(m, n, k), then the rotating electric machine 7 shown in Figure 22 has 1≦m≦M, 1≦n≦N, 1≦k≦K, and M=4, N=5, and K=2.

[0100] The coils of the rotating electric machine 7 are arranged counterclockwise in ascending order of k, ascending order of n, and ascending order of m. Specifically, C(1,1,1), C(1,1,2), C(1,2,1), C(1,2,2), C(1,3,1), C(1,3,2), C(1,4,1), C(1,4,2), C(1,5,1), C(1,5,2), C(2,1,1), C(2,1,2), C(2,2,1), C(2,2,2), C(2,3,1), C(2,3,2), C(2,4,1), C(2,4,2), C(2,5,1), C(2,5,2), C( They are arranged in the following order: C(3, 1, 1), C(3, 1, 2), C(3, 2, 1), C(3, 2, 2), C(3, 3, 1), C(3, 3, 2), C(3, 4, 1), C(3, 4, 2), C(3, 5, 1), C(3, 5, 2), C(4, 1, 1), C(4, 1, 2), C(4, 2, 1), C(4, 2, 2), C(4, 3, 1), C(4, 3, 2), C(4, 4, 1), C(4, 4, 2), C(4, 5, 1), and C(4, 5, 2).

[0101] By arranging the coils of each group and each phase consecutively in the circumferential direction in this way, the difference in amplitude of the voltage waveform between phases due to the imbalance in the magnetic gap length increases. When the difference in amplitude of the voltage waveform between phases increases, the L±P order harmonic components of each line voltage used to estimate the magnetic gap length also increase, so the estimation accuracy of the magnetic gap length can be improved.

[0102] <Another measurement target> In addition, without being limited to the above example, a case will be described in which another rotating electric machine 7 having 8 poles and 20 slots and assumed to be driven by a 4-group, 5-phase inverter as shown in FIG. 23 is used as a measurement target. The coils of the stator 71 are configured as group 1 to group 4, and each group is arranged with a mechanical angle phase difference of 360 / 4=90°. In addition, in FIG. 23, the direction of the current flowing through each coil is indicated by two types of symbols. The stator 71 of this rotating electric machine 7 has a distributed winding structure in which coils are arranged across multiple slots. The coils of each group are configured with five phases, A, B, C, D, and E. The coils of each group are wound so that they are continuous in the circumferential direction in the order of A, B, C, D, and E.

[0103] That is, if the k-th coil of m groups, n phases in a rotating electric machine composed of M groups, N phases, each of which has K coils, is expressed as C(m, n, k), then the rotating electric machine 7 shown in Fig. 23 satisfies 1 < m < M, 1 < n < N, 1 < k < K, and M = 4, N = 5, and K = 1. The coils of this rotating electric machine 7 are arranged counterclockwise in ascending order of k, ascending order of n, and ascending order of m. Specifically, they are arranged in the following order: C(1, 1, 1), C(1, 2, 1), C(1, 3, 1), C(1, 4, 1), C(1, 5, 1), C(2, 1, 1), C(2, 2, 1), C(2, 3, 1), C(2, 4, 1), C(2, 5, 1), C(3, 1, 1), C(3, 2, 1), C(3, 3, 1), C(3, 4, 1), C(3, 5, 1), C(4, 1, 1), C(4, 2, 1), C(4, 3, 1), C(4, 4, 1), and C(4, 5, 1).

[0104] By arranging the coils of each group and each phase consecutively along the circumferential direction in this way, the difference between the phases in the amplitude of the voltage waveform due to the imbalance in the magnetic gap length becomes large. When the difference between the phases in the amplitude of the voltage waveform becomes large, the L±P-th harmonic components of each line voltage used to estimate the magnetic gap length also become large, so the estimation accuracy of the magnetic gap length can be improved.

[0105] In the fifth embodiment, the voltage acquisition unit 2 of the magnetic gap length estimation device 1 is connected to each of the 20 connections 9 connecting the 4 groups, 5 phase windings and the rotating electric machine 7, but the present invention is not limited to this. Even if all of the 20 connections 9 are not connected to the voltage acquisition unit 2, if a minimum line voltage waveform that can create a Lissajous curve can be acquired, the direction in which the magnetic gap length changes can be estimated.

[0106] Embodiment 6 In the sixth embodiment, similar to the relationship between the first and second embodiments and the relationship between the third and fourth embodiments, a driving device for a rotating electric machine and a rotating electric machine system including the magnetic gap length estimation device described in the fifth embodiment will be described. Fig. 24 is a block diagram for explaining the configuration of the driving device for a rotating electric machine and the rotating electric machine system according to the sixth embodiment. The configuration and operation of the magnetic gap length estimation device itself are the same as those in the fifth embodiment, and therefore a description of the similar parts will be omitted.

[0107] 24, a driving device 10 of a rotating electric machine in the sixth embodiment includes the magnetic gap length estimation device 1 described in the fifth embodiment, and a control parameter calculation unit 5 that receives an output from the instantaneous gap length estimation unit 4 and sends a control parameter to the inverter 8. The rotating electric machine 7, the inverter 8, and the driving device 10 form a rotating electric machine system 100. The control parameter calculation unit 5 sends a control parameter for adjusting a current input value to each group of the rotating electric machine 7 to each of the four inverters 8a to 8d, based on the magnetic gap length estimated by the magnetic gap length estimation device 1.

[0108] That is, also in the driving device 10 according to the sixth embodiment, the magnetic gap length estimation device 1 has an external output terminal 4t shown in FIG. 21 connected to the control parameter calculation unit 5. On the other hand, the control parameter calculation unit 5 has an external output terminal 5t, and for example, by connecting an external monitor to this external output terminal 5t, the control parameters can be visualized. Of course, information on the state of the magnetic gap obtained from the magnetic gap length estimation device 1 may also be output from the external output terminal 5t and visualized.

[0109] As with the above configuration and as described in the second embodiment, the detection phase Ph2 is performed based on the estimated information obtained in the pre-processing phase Ph1, and the variation characteristic of the magnetic gap length according to the rotational position of the rotor 72 is obtained. In other words, the control operation of the drive device 10 will be described on the premise that the variation characteristic of the magnetic gap length according to the rotational position of the rotor 72 has been obtained.

[0110] For example, assume that the magnetic gap length in group 3 at a certain rotational position (instantaneous time) is smaller than the magnetic gap lengths in groups 1, 2, and 4. In that case, the current input value to the coils belonging to group 3 at that rotational position (instantaneous time) is set to be smaller than the current input value to the coils belonging to groups 1, 2, and 4.

[0111] As time passes, if the position where the magnetic gap length becomes smaller is located in a different group, the current value of that group is set smaller than the other groups, and so on. By controlling in this manner, it is possible to construct a rotating electric machine system 100 that reduces vibration and noise caused by dynamic eccentricity.

[0112] In the sixth embodiment as well, an example is shown in which the voltage acquisition unit 2 of the magnetic gap length estimation device 1 is connected to each of the 20 connections 9 connecting the four groups of five phase windings and the rotating electric machine 7. However, similarly to the fifth embodiment in which the magnetic gap length estimation device 1 is used alone, if it can acquire a minimum line voltage waveform that allows a Lissajous curve to be created, it can estimate the direction in which the magnetic gap length changes and calculate the control parameters.

[0113] The magnetic gap length estimation device according to the first, third and fifth embodiments and the driving device for the rotating electric machine according to the second, fourth and sixth embodiments may be configured as hardware 1000 including a processor 1001 and a storage device 1002, as shown in FIG. 25. The storage device 1002 includes a volatile storage device such as a random access memory and a non-volatile auxiliary storage device such as a flash memory, although not shown in the figure. Also, instead of the flash memory, a hard disk auxiliary storage device may be included. The processor 1001 executes a program input from the storage device 1002. In this case, the program is input from the auxiliary storage device to the processor 1001 via the volatile storage device. Also, the processor 1001 may output data such as a calculation result to the volatile storage device of the storage device 1002, or may store the data in the auxiliary storage device via the volatile storage device.

[0114] Other forms. The magnetic gap length estimation devices described in the first, third and fifth embodiments estimate the magnetic gap length for a rotating electric machine 7 with six poles (electrode pairs L=3) by using the third component which is the fundamental wave of the line voltage and the second and fourth components which are characteristic quantities of dynamic eccentricity. For a rotating electric machine 7 with ten poles (electrode pairs L=5), the magnetic gap length is estimated by using the fifth component which is the fundamental wave of the line voltage and the fourth and sixth components which are characteristic quantities of dynamic eccentricity. For a rotating electric machine 7 with eight poles (electrode pairs L=4), the magnetic gap length is estimated by using the fourth component which is the fundamental wave of the line voltage and the third and fifth components which are characteristic quantities of dynamic eccentricity. In other words, the magnetic gap length estimation device 1 of the present application can estimate the magnetic gap length for a rotating electric machine 7 with an L pole pair by using the L±Pth harmonic components of the line voltage.

[0115] In addition, if the k-th coil of m groups and n phases in a rotating electric machine consisting of M groups and N phases with K coils for each phase is expressed as C(m, n, k), then 1≦m≦M, 1≦n≦N, and 1≦k≦K. The coils are then arranged counterclockwise in the following order: C(1, 1, 1), C(1, 1, 2), ···C(1, 1, K), C(1, 2, 1), ···C(1, 2, K), ···C(1, N, K), C(2, 1, 1), ···C(M, N, K). In other words, the coils are arranged in ascending order of coil numbers, phase numbers, and group numbers in a counterclockwise direction.

[0116] This causes a large difference between the phases in the amplitude of the voltage waveform due to the imbalance in the magnetic gap length. When the difference between the phases in the amplitude of the voltage waveform becomes large, the L±P-order harmonic components of each line voltage used to estimate the magnetic gap length also become large, so that the estimation accuracy of the magnetic gap length can be improved. Even if a rotating electric machine system 100 is constructed that includes a rotating electric machine 7 in which eccentricity has occurred during the manufacturing process, the rotating electric machine 7 can be driven by correcting the control parameters according to the estimated gap length, so that vibration and noise caused by dynamic eccentricity can be reduced.

[0117] Although an example has been shown in which the coils are arranged counterclockwise in ascending order of coil number (k), phase number (n), and group number (m), the same effect can be obtained when they are arranged clockwise. In other words, the same effect can be obtained by arranging the coils so that the coil number (k), phase number (n), and group number (m) change sequentially along the circumferential direction.

[0118] Although various exemplary embodiments are described in this application, various features, aspects, and functions described in one or more embodiments are not limited to application in a specific embodiment, but can be applied to the embodiments alone or in various combinations. Therefore, countless modifications not illustrated are expected within the scope of the technology disclosed in this specification. For example, the modification, addition, or omission of at least one component, and the extraction and combination of at least one component with components of other embodiments are included.

[0119] As described above, the magnetic gap length estimation device 1 of the present application includes a voltage acquisition unit 2 that acquires a line-to-line induced voltage induced in the connection 9 between the rotating electric machine 7 having multiple groups of coils when multiple phase coils are grouped together and the inverter 8 that drives the rotating electric machine 7, an estimation information creation unit 3 that creates estimation information corresponding to the rotating electric machine 7 for estimating the magnetic gap length from the waveform of the line-to-line induced voltage when the rotating electric machine 7 is rotated in an unloaded state, and an instantaneous gap length estimation unit 4 that estimates the instantaneous magnetic gap length from the instantaneous value of the line-to-line induced voltage and the estimation information. Therefore, it is possible to estimate the magnetic gap length without requiring additional equipment such as a current sensor or a current load, and to suppress vibrations and noise caused by its fluctuations.

[0120] In particular, the estimated information creation unit 3 includes a spectrum analysis unit 341 that converts the waveform into amplitude and phase for each frequency, a frequency analysis unit 342 that extracts the fundamental wave component of the line-to-line induced voltage and the amplitude and phase of the L±P order harmonic components from the amplitude and phase for each converted frequency, where P is an integer greater than or equal to 1 and L is the number of pole pairs in the stator 71 of the rotating electric machine 7, and an estimated information calculation unit 35 that calculates estimated information from the extracted amplitudes and phases of the fundamental wave component and the L±P order harmonic components, so that the instantaneous value of the magnetic gap length which varies with time can be easily estimated.

[0121] If the voltage acquiring unit 2 acquires at least one out-of-group in-phase line induced voltage from among the line induced voltages, the magnetic gap length can be estimated with high accuracy with a simple configuration.

[0122] Furthermore, the driving device 10 of the rotating electric machine of the present application includes the above-mentioned magnetic gap length estimation device 1 and a control parameter calculation unit 5 that calculates control parameters of the inverter 8 based on the instantaneous magnetic gap length estimated by the magnetic gap length estimation device 1. Therefore, the magnetic gap length can be estimated without requiring additional equipment such as a current sensor or a current load, and vibrations and noise caused by its fluctuations can be suppressed.

[0123] Furthermore, since the rotating electric machine system 100 of the present application includes the above-mentioned rotating electric machine driving device 10, the inverter 8 controlled by the rotating electric machine driving device 10, and the rotating electric machine 7 driven by the inverter 8, it is possible to suppress vibrations and noise caused by fluctuations in the magnetic gap length.

[0124] If the coils of each group of the rotary electric machine 7 are arranged with a mechanical angle phase difference obtained by dividing 360 degrees by the number of groups, the accuracy of detecting the fluctuation (eccentricity) of the magnetic gap length is improved.

[0125] In this case, if the coils are arranged so that the coil numbers, phase numbers, and group numbers change sequentially along the circumferential direction, the detection accuracy is further improved.

[0126] Furthermore, if the coils in each group are configured in a Y-type configuration with each phase connected in series, the detection accuracy is further improved.

[0127] In this case, if the neutral points of each group of Y-connected rotary electric machine 7 are electrically connected to each other, it is possible to prevent an offset voltage between neutral points from being mixed into the detected voltage waveform, thereby improving detection accuracy.

[0128] Furthermore, by configuring the coils so that the electrical phase difference between the different groups and the same phase coils at circumferential positions is 0 degrees, the fundamental wave components of the different groups and the same phase line voltages are canceled out, improving detection accuracy.

[0129] As described above, according to the magnetic gap length estimation method of the present application, when multiple phase coils are grouped into one group, the rotating electric machine 7 having multiple groups of coils is rotated at a constant rotation speed in an unloaded state for at least one revolution, and waveforms of line-to-line induced voltages induced in the rotating electric machine 7 and the connections 9 of the inverter 8 that drives the rotating electric machine 7 are acquired, and estimation information corresponding to the rotating electric machine 7 for estimating the magnetic gap length is created (pre-processing phase Ph1), and an instantaneous magnetic gap length estimation step (detection phase Ph2) of estimating the instantaneous magnetic gap length from the instantaneous value of the line-to-line induced voltage and the estimation information is included. Therefore, the magnetic gap length can be estimated without requiring additional equipment such as a current sensor or current load, and vibrations and noise caused by its fluctuations can be suppressed.

[0130] If the step of creating the estimated information (pre-processing phase Ph1) is configured to include a step (step S11) of measuring the waveforms of the line voltages between same group different phases and different group same phases as the line induced voltages, where P is an integer equal to or greater than 1 and the number of pole pairs of the stator 71 of the rotating electric machine 7 is L, a step (steps S12 to S15) of extracting the fundamental wave component and L±P-th harmonic components of the line voltage from the measured waveform and estimating the amount of variation in the magnetic gap length and the relative displacement direction of the magnetic gap length with respect to the magnetic pole position, and a step (step S16) of creating a Lissajous curve as estimated information from the waveform, accurate estimated information for estimating the magnetic gap length can be easily obtained without requiring additional equipment such as a current sensor or a current load.

[0131] If the instantaneous gap length estimation step (detection phase Ph2) includes a step (step S21) of measuring instantaneous values ​​of line voltages between same-group different phases and different-group same-phase as line-to-line induced voltages, a step (steps S22 to S23) of comparing the arctangent of the instantaneous value with estimated information, and a step (step S24) of estimating the instantaneous absolute displacement direction of the magnetic gap length based on the comparison result, the instantaneous value of the magnetic gap length that varies with time can be easily estimated without requiring additional equipment such as a current sensor or a current load. By using the result, the rotating electric machine 7 can be driven and controlled in real time to suppress vibrations and noise caused by the variation in the magnetic gap length. [Explanation of symbols]

[0132] 1: magnetic gap length estimation device, 10: driving device for rotating electric machine, 100: rotating electric machine system, 2: voltage acquisition unit, 3: estimated information creation unit, 341: spectrum analysis unit, 342: frequency analysis unit, 35: estimated information calculation unit, 4: instantaneous gap length estimation unit, 5: control parameter calculation unit, 7: rotating electric machine, 8: inverter, 9: wiring, L: number of pole pairs, α: displacement direction.

Claims

1. a voltage acquisition unit that acquires a line-to-line induced voltage induced in a connection between a rotating electric machine having a plurality of groups of coils when the coils of a plurality of phases are grouped together and an inverter that drives the rotating electric machine; an estimation information creation unit that creates estimation information corresponding to the rotating electric machine for estimating a magnetic gap length from a waveform of the line induced voltage when the rotating electric machine is rotated in an unloaded state; and an instantaneous magnetic gap length estimation unit that estimates the instantaneous magnetic gap length from the instantaneous value of the line induced voltage and the estimated information; A magnetic gap length estimation device comprising:

2. The estimated information creation unit, A spectrum analyzer that converts the waveform into amplitude and phase for each frequency; a frequency analysis unit that extracts amplitudes and phases of a fundamental wave component of the line-to-line induced voltage and an L±P-th harmonic component from the amplitude and phase of each of the converted frequencies, where P is an integer equal to or greater than 1 and the number of pole pairs of the stator of the rotating electric machine is L; and an estimated information calculation unit that calculates the estimated information from the amplitudes and phases of the extracted fundamental wave component and the L±P order harmonic components; 2. The magnetic gap length estimation device according to claim 1, further comprising:

3. 3. The magnetic gap length estimation device according to claim 1, wherein the voltage acquisition unit acquires at least one out-of-group in-phase line induced voltage from among the line induced voltages.

4. A magnetic gap length estimation device according to any one of claims 1 to 3, and a control parameter calculation unit that calculates a control parameter of the inverter based on the instantaneous magnetic gap length estimated by the magnetic gap length estimation device; A driving device for a rotating electric machine comprising:

5. The driving device for a rotating electric machine according to claim 4, The inverter controlled by a drive device of the rotating electric machine, and The rotating electric machine driven by the inverter; A rotating electric machine system comprising:

6. 6. The rotating electric machine system according to claim 5, wherein the rotating electric machine has a stator in which the coils for each group are arranged with a mechanical angle phase difference obtained by dividing 360 degrees by the number of groups.

7. 7. The rotating electric system according to claim 6, wherein the coils are arranged such that the coil numbers, phase numbers, and group numbers change sequentially along the circumferential direction.

8. 8. The rotating electrical system according to claim 6, wherein the coils in each group are configured in a Y-connection in which the coils are connected in series for each phase.

9. 9. The rotating electric machine system according to claim 8, wherein neutral points of each of the Y-connected groups of the rotating electric machine are electrically connected to each other.

10. 10. The rotating electric system according to claim 5, wherein the coils are arranged such that an electrical phase difference between different groups of in-phase coils at circumferential positions is 0 degrees.

11. A step of rotating a rotating electric machine having multiple groups of coils at a constant rotation speed in an unloaded state for at least one revolution, acquiring a waveform of a line-to-line induced voltage induced in a connection between the rotating electric machine and an inverter that drives the rotating electric machine, and creating estimation information corresponding to the rotating electric machine for estimating a magnetic gap length; and an instantaneous magnetic gap length estimation step of estimating the instantaneous magnetic gap length from the instantaneous value of the line induced voltage and the estimated information; A magnetic gap length estimation method comprising:

12. The step of generating the estimated information includes: measuring waveforms of line voltages between different phases in the same group and between same phases in different groups as the line induced voltages; extracting a fundamental wave component and an L±P-th harmonic component of the line voltage from the waveform, where P is an integer equal to or greater than 1, and L is the number of pole pairs of the stator of the rotating electric machine, and estimating a variation amount of the magnetic gap length and a relative displacement direction of the magnetic gap length with respect to a magnetic pole position; creating a Lissajous curve as the estimated information from the waveform; The method for estimating a magnetic gap length according to claim 11, further comprising:

13. The instantaneous gap length estimation step includes: measuring instantaneous values ​​of line voltages between different phases in the same group and between same phases in different groups as the line induced voltages; comparing the arctangent of the instantaneous value with the estimated information; and estimating an instantaneous absolute displacement direction of the magnetic gap length based on a result of the comparison; 13. The method for estimating a magnetic gap length according to claim 11, further comprising:

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