Eccentricity Estimation System

Abstract

To enable eccentricity estimation even in a rotating electric machine with salient poles. [Solution] The eccentricity estimation system 2 divides the coils into a first coil group including first coil portions arranged opposite each other along a first opposing axis, and a second coil group including second coil portions arranged opposite each other along a second opposing axis different from the first opposing axis, and is equipped with an inspection voltage application unit 22 that applies an inspection voltage to each coil portion included in each coil group, a shared voltage detection unit 23 that measures the shared voltage in the first coil portion and the second coil portion when the inspection voltage is applied, an angle estimation unit 24 that estimates the angle between the d-axis or q-axis of the rotor of the rotating electric machine 3 and the first opposing axis or the second opposing axis, and an eccentricity estimation unit 25 that estimates the amount of eccentricity of the rotor based on the shared voltage and angle.

Description

[Technical Field]

[0001] The present disclosure relates to an eccentricity estimation system for a rotating electrical machine. [Background technology]

[0002] The technology described in Patent Document 1 below is known as a technique for estimating the eccentricity ratio and eccentricity direction between a rotor and a stator in a rotating electrical machine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-229226 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, AC voltages of different frequencies are simultaneously applied to both ends of a winding group, each of which has two windings connected in series and positioned symmetrically with respect to the central axis of the stator, which is parallel to the rotation axis of the rotor, and another winding group, each of which has two windings connected in series and positioned symmetrically with respect to the central axis of the stator, but at a different angle from the first winding group, and the terminal voltage of each winding is measured to estimate the magnitude and direction of eccentricity.

[0005] The technology described in Patent Document 1 is based on the premise that only changes in gap length due to eccentricity affect the terminal voltage of each winding group. However, in a rotating electric machine with salient poles, for example, the influence of the rotor rotation angle can cause errors in eccentricity estimation. More specifically, when the rotor rotation angle changes, the terminal voltage of the winding group will change even if the eccentric position remains the same.

[0006] An object of the present disclosure is to enable eccentricity estimation even for a rotating electric machine with salient poles. [Means for solving the problem]

[0007] The present disclosure provides an eccentricity estimation system for a rotating electric machine including a rotor with non-uniform magnetic reluctance in the circumferential direction and a stator with multiple windings provided in the circumferential direction, wherein the multiple windings are divided into a first coil group including first coil portions arranged opposite each other along a first opposing axis passing through the center of the stator, and a second coil group including second coil portions arranged opposite each other along a second opposing axis passing through the center and different from the first opposing axis, and the system is equipped with: an inspection voltage application unit that applies an inspection voltage to each coil portion included in each coil group; a shared voltage detection unit that measures the shared voltage in the first coil portion and the shared voltage in the second coil portion when the inspection voltage is applied; an angle estimation unit that estimates the angle between the d-axis or q-axis of the rotor and the first opposing axis or the second opposing axis; and an eccentricity estimation unit that estimates the amount of eccentricity of the rotor based on the shared voltage and angle.

[0008] In the present disclosure, the angle estimator may be replaced with an angle controller that controls the angle between the d-axis or q-axis of the rotor and the first opposing shaft or the second opposing shaft to a predetermined angle. [Effects of the Invention]

[0009] According to the present disclosure, eccentricity estimation is possible even for a rotating electrical machine with salient poles. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing the overall configuration of an eccentricity estimation system according to this embodiment. [Figure 2] FIG. 2 is a diagram for explaining the configuration of the rotating electric machine shown in FIG. [Figure 3] FIG. 3 is a connection diagram of the stator windings in the rotating electric machine shown in FIG. [Figure 4] FIG. 4 is a flowchart of the eccentricity estimation performed by the eccentricity estimation system shown in FIG. [Figure 5] FIG. 5 is a wiring diagram for estimating the amount of eccentricity in the stator winding shown in FIG. [Figure 6]FIG. 6 is a wiring diagram for estimating the amount of eccentricity in the stator winding shown in FIG. [Figure 7] FIG. 7 is a diagram for explaining the relationship between the amount of eccentricity and the shared voltage in the rotating electric machine shown in FIG. [Figure 8] FIG. 8 is a diagram for explaining the eccentricity estimation error. [Figure 9] FIG. 9 is a block diagram showing the overall configuration of an eccentricity estimation system according to another example of this embodiment. [Figure 10] FIG. 10 is a flowchart of the eccentricity estimation executed by the eccentricity estimation system shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0012] 1, the eccentricity estimation system 2 is a system that estimates the eccentricity between a rotor and a stator in a rotating electric machine 3. The eccentricity estimation system 2 includes a centralized or distributed microcomputer. The eccentricity estimation system 2 includes an inspection voltage application unit 22, a shared voltage detection unit 23, an angle estimation unit 24, and an eccentricity estimation unit 25.

[0013] Prior to describing the eccentricity estimation system 2, the rotating electric machine 3 will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a cross-sectional view taken along a plane intersecting the rotation axis of the rotating electric machine 3. Fig. 3 is a diagram for explaining the connection state of a U-phase winding, a V-phase winding, and a W-phase winding that constitute the rotating electric machine 3.

[0014] The rotating electric machine 3 includes an embedded magnet rotor 12 with non-uniform magnetic resistance in the circumferential direction, and a stator 11 with a three-phase winding provided in the circumferential direction. A plurality of permanent magnets 13 are arranged at equal intervals in the circumferential direction on the rotor 12. A d-axis 31 is set as the central axis of the permanent magnets 13, and a q-axis 32 is set as the axis between the permanent magnets 13. The stator 11 is provided with a U-phase winding, a V-phase winding, and a W-phase winding.

[0015] The U-phase winding includes coil portions U1, U2, U3, and U4. The V-phase winding includes coil portions V1, V2, V3, and V4. The W-phase winding includes coil portions W1, W2, W3, and W4.

[0016] 2, a pair of symbols, one with a black circle in the center of each coil portion and the other with an X inside the coil portion, indicate windings. The U-phase winding, the V-phase winding, and the W-phase winding are arranged in the slots of the stator 11, mechanically offset from each other by 30 degrees.

[0017] For example, coil portion V1 is disposed at a position shifted 30 degrees counterclockwise from coil portion U1, and coil portion W1 is disposed at a position shifted 30 degrees counterclockwise from coil portion V1.

[0018] As described above, the U-phase winding, V-phase winding, and W-phase winding are arranged with a 30-degree offset from one another. Therefore, the arrangement of each coil portion constituting each winding is the same within each winding. The arrangement and connection of each coil portion will be explained using the U-phase winding as an example.

[0019] As shown in FIG. 2, coil portion U1 and coil portion U3 are arranged opposite each other with the center C of the stator 11 in between. The axis connecting the center of coil portion U1 and the center of coil portion U3 is the first opposing axis. Similarly, coil portion U2 and coil portion U4 are arranged opposite each other with the center C of the stator 11 in between. The axis connecting the center of coil portion U2 and the center of coil portion U4 is the second opposing axis.

[0020] 3, the coil portions constituting each winding are connected in series from the terminals to the neutral point. In the U-phase winding, coil portions U1, U2, U3, and U4 are connected in series from U-phase terminal 14 to neutral point 15.

[0021] A lead wire 161 is provided between coil portion U1 and coil portion U2. A lead wire 162 is provided between coil portion U2 and coil portion U3. A lead wire 163 is provided between coil portion U3 and coil portion U4. A lead wire 164 is provided so as to pass from coil portion U4 to neutral point 15. The U-phase winding is configured so that the shared voltage from U-phase terminal 14 to neutral point 15 can be measured by providing lead wires 161, 162, 163, and 164.

[0022] Next, the test voltage application unit 22, the shared voltage detection unit 23, the angle estimation unit 24, and the eccentricity estimation unit 25 of the eccentricity estimation system 2 will be described.

[0023] Inspection voltage application unit 22 divides the windings constituting the same phase among the windings of multiple phases into a first coil group including multiple first coil portions (e.g., coil portion U1 and coil portion U3) arranged opposite each other along a first opposing axis passing through center C of stator 11, and a second coil group including second coil portions (e.g., coil portion U2 and coil portion U4) arranged opposite each other along a second opposing axis passing through center C and different from the first opposing axis, and applies an inspection voltage to each coil group. The method of applying the inspection voltage will be described in detail later.

[0024] The shared voltage detection unit 23 is a unit that measures the shared voltage of the first coil portion and the second coil portion when the test voltage is applied. The method of measuring the shared voltage will be described in detail later.

[0025] The angle estimation unit 24 is a part that estimates the angle formed between the d-axis 31 or q-axis 32 of the rotor 12 and the first opposing shaft or the second opposing shaft. The angle estimation method will be described in detail later.

[0026] The eccentricity estimation unit 25 is a part that estimates the amount of eccentricity of the rotor 12 based on the shared voltage and angle. The method for estimating the amount of eccentricity will be described in detail later.

[0027] Next, the operation of the eccentricity estimation system 2 will be described with reference to Fig. 4. In step S01, the eccentricity estimation unit 25 selects an axis for which the amount of eccentricity is to be estimated. The eccentricity estimation unit connects the test voltage application unit 22 and the shared voltage detection unit 23 to the leads 161, 162, 163, and 164 so as to match the selected axis.

[0028] Fig. 5 shows a wiring diagram in which the eccentricity estimation unit 25 estimates the amount of eccentricity in the first opposing shaft where the coil portion U1 and the coil portion U3 are opposed to each other. In Fig. 5, the shared voltage detection unit 23 includes a high-side shared voltage detection unit 23H and a low-side shared voltage detection unit 23L.

[0029] The eccentricity estimation unit 25 short-circuits the coil portion U2 by connecting the jumper wire 26 to the lead wire 161 and the lead wire 162. The inspection voltage application unit 22 is connected so as to apply a voltage between the U-phase terminal 14 and the lead wire 163.

[0030] The shared voltage detection unit 23H is connected to detect the voltage between the U-phase terminal 14 and the lead-out wire 161. The shared voltage detection unit 23H detects the shared voltage VH of the coil portion U1. The shared voltage detection unit 23L is connected to detect the voltage between the lead-out wire 162 and the lead-out wire 163. The shared voltage detection unit 23L detects the shared voltage VL of the coil portion U3.

[0031] Fig. 6 shows a wiring diagram in which the eccentricity estimation unit 25 estimates the amount of eccentricity in the second opposing shaft where the coil portion U2 and the coil portion U4 are opposed to each other. In Fig. 6, the shared voltage detection unit 23 includes a high-side shared voltage detection unit 23H and a low-side shared voltage detection unit 23L.

[0032] The eccentricity estimation unit 25 short-circuits the coil portion U3 by connecting the jumper wire 26 to the lead wire 162 and the lead wire 163. The inspection voltage application unit 22 is connected to apply a voltage between the lead wire 161 and the lead wire 164.

[0033] The shared voltage detection unit 23H is connected to detect the voltage between the lead-out wire 161 and the lead-out wire 162. The shared voltage detection unit 23H detects the shared voltage VH of the coil portion U2. The shared voltage detection unit 23L is connected to detect the voltage between the lead-out wire 163 and the lead-out wire 164. The shared voltage detection unit 23L detects the shared voltage VL of the coil portion U4.

[0034] The description will continue with reference to Figure 4 again. In step S02 following step S01, angle estimation unit 24 estimates the rotor angle of rotor 12. The rotor angle is the angle between the opposing axis for which the eccentricity of rotor 12 is to be estimated and d-axis 31 or q-axis 32 of rotor 12.

[0035] In step S03 following step S02, the eccentricity estimation unit 25 selects the shared voltage ratio-eccentricity amount characteristic according to the rotor angle.

[0036] The characteristics of the shared voltage ratio and eccentricity amount according to the rotor angle will be described with reference to Figure 7. Figure 7 illustrates a case where the first opposing shaft formed by the coil portion U1 and the coil portion U3 is selected as the opposing shaft. When the rotor 12 is not eccentric, the inductances of the coil portions U1 and U3 are all the same, so the shared voltage ratio VH / VL is "1".

[0037] In state [a], the first opposing shaft is in a q-axis facing state along the q-axis 32 and is eccentric to the coil portion U1 side by an eccentricity amount d1. In state [b], the first opposing shaft is in a q-axis facing state along the q-axis 32 and is eccentric to the coil portion U3 side by an eccentricity amount d3.

[0038] In state [c], the first opposing shaft is in a d-axis opposing state along the d-axis 31 and is eccentric to the coil portion U1 side by an eccentricity amount d1. In state [d], the first opposing shaft is in a d-axis opposing state along the d-axis 31 and is eccentric to the coil portion U3 side by an eccentricity amount d3.

[0039] As shown in FIG. 7, the change in the shared voltage ratio VH / VL is smaller in states [c] and [d], which are the d-axis opposing states, than in states [a] and [b], which are the q-axis opposing states. This is because, in the d-axis opposing state, the proportion of low-permeability sections, such as air layers and magnets, in the magnetic path including the windings is large, so the change in inductance relative to the change in air gap length due to eccentricity is small. In step S03, for example, if the rotor angle is in the q-axis opposing state, the eccentricity estimation unit 25 selects the shared voltage ratio vs. eccentricity characteristic exemplified by the line connecting states [a] and [b]. For example, if the rotor angle is in the d-axis opposing state, the eccentricity estimation unit 25 selects the shared voltage ratio vs. eccentricity characteristic exemplified by the line connecting states [c] and [d].

[0040] In step S04 following step S03, the shared voltage detection unit 23 reads the shared voltages VH, VL corresponding to the set opposing axis. For example, if the set opposing axis is the first opposing axis, the shared voltages VH, VL of the coil portions U1, U3 are read, and if the set opposing axis is the second opposing axis, the shared voltages VH, VL of the coil portions U2, U4 are read. The shared voltage detection unit 23 calculates the shared voltage ratio VH / VL using the read shared voltages.

[0041] In step S05 following step S04, the eccentricity estimation unit 25 calculates the amount of eccentricity corresponding to the set opposing shaft. Specifically, the amount of eccentricity corresponding to the shared voltage ratio VH / VL is identified using the shared voltage ratio vs. eccentricity characteristic illustrated in Fig. 7.

[0042] In step S06 following step S05, the eccentricity estimation unit 25 determines whether there are any opposing shafts that have not yet been measured. For example, if the measurement targets are the first opposing shaft and the second opposing shaft, it determines whether calculation of the eccentricity amount has been completed for both opposing shafts.

[0043] If it is determined in step S06 that there is an unmeasured opposing axis, the process proceeds to step S01. If it is determined in step S06 that there is no unmeasured opposing axis, the process ends.

[0044] When there is saliency, as in the rotor 12 constituting the rotating electric machine 3, the winding inductance characteristics corresponding to the amount of eccentricity differ depending on the rotation angle, as explained with reference to Fig. 7. Therefore, if the rotation angle is not taken into consideration and the shared voltage is obtained at a rotation angle at which the coil portion U1 and the q axis face each other, and the shared voltage ratio characteristic with respect to eccentricity is obtained when the coil portion U1 faces the d axis, an eccentricity estimation error will occur, as shown in Fig. 8. In this embodiment, this error is eliminated by preventing discrepancies between the shared voltage ratio characteristic and the rotation angle, thereby achieving highly accurate eccentricity estimation.

[0045] An eccentricity estimation system 2A as a modified example will be described with reference to Fig. 9. In the eccentricity estimation system 2A, the angle estimation unit 24 of the eccentricity estimation system S is replaced with an angle control unit 24A. The test voltage application unit 22 and the shared voltage detection unit 23 are the same as those described above, and therefore description thereof will be omitted.

[0046] Angle control unit 24A is a unit that controls the angle between d-axis 31 or q-axis 32 of rotor 12 and the first opposing shaft or the second opposing shaft to a predetermined angle. An angle command value for setting the predetermined angle is output from eccentricity estimation unit 25 to angle control unit 24A. Angle control unit 24A sets the rotation angle of rotor 12 at the time of eccentricity estimation by matching it to the angle command value. Methods for controlling the rotation angle of rotor 12 include angle adjustment using an external power source and a method that utilizes a magnetic field generated by passing a direct current through stator 11.

[0047] Next, the operation of the eccentricity estimation system 2A will be described with reference to Fig. 10. In step S11, the eccentricity estimation unit 25 selects an axis for which the amount of eccentricity is to be estimated. The eccentricity estimation unit connects the test voltage application unit 22 and the shared voltage detection unit 23 to the leads 161, 162, 163, and 164 so as to match the selected axis.

[0048] In step S12 following step S11, angle estimation unit 24 sets the rotor angle of rotor 12 and outputs an angle command value to angle control unit 24A. Angle control unit 24A controls the rotor angle of rotor 12 so as to conform to the angle command value. The rotor angle is the angle formed between the opposing axis for estimating the eccentricity of rotor 12 and d-axis 31 or q-axis 32 of rotor 12.

[0049] In step S13 following step S12, the shared voltage detection unit 23 reads the shared voltages VH, VL corresponding to the set opposing axis. For example, if the set opposing axis is the first opposing axis, the shared voltages VH, VL of the coil portions U1, U3 are read, and if the set opposing axis is the second opposing axis, the shared voltages VH, VL of the coil portions U2, U4 are read. The shared voltage detection unit 23 calculates the shared voltage ratio VH / VL using the read shared voltages.

[0050] In step S14 following step S13, the eccentricity estimation unit 25 calculates the amount of eccentricity corresponding to the set opposing shaft. Specifically, the amount of eccentricity corresponding to the shared voltage ratio VH / VL is determined using the shared voltage ratio vs. eccentricity characteristic illustrated in Fig. 7.

[0051] In step S15 following step S14, the eccentricity estimation unit 25 determines whether there are any opposing shafts that have not yet been measured. For example, if the measurement targets are the first opposing shaft and the second opposing shaft, it determines whether calculation of the eccentricity amounts for both opposing shafts has been completed.

[0052] If it is determined in step S15 that there is an unmeasured opposing axis, the process proceeds to step S01. If it is determined in step S15 that there is no unmeasured opposing axis, the process ends.

[0053] As shown in Fig. 7, the sensitivity of the shared voltage ratio to the amount of eccentricity is higher for q-axis opposition than for d-axis opposition. Therefore, it is preferable that the eccentricity estimator 25 outputs an angle command value for setting the first and second opposing shafts so as to be opposed to the q-axis. The eccentricity estimation system 2A makes it possible to estimate eccentricity with high sensitivity of the shared voltage ratio vs. eccentricity characteristic, thereby improving the reliability of the eccentricity estimation accuracy.

[0054] The eccentricity estimation system 2, 2A and the method thereof described in the present disclosure may be implemented by a special purpose computer provided by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the eccentricity estimation system 2, 2A and the method thereof described in the present disclosure may be implemented by a special purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the eccentricity estimation system 2, 2A and the method thereof described in the present disclosure may be implemented by one or more special purpose computers provided by a combination of a processor and memory programmed to perform one or more functions and a processor configured with one or more hardware logic circuits. The computer program may also be stored on a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

[0055] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of each of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of each of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise.

[0056] [Note] Notes 1 and 2 below can be combined in any way as long as there is no technical contradiction.

[0057] [Appendix 1] An eccentricity estimation system (2) for a rotating electric machine (3) including a rotor (12) having non-uniform magnetic resistance in the circumferential direction and a stator (11) having a plurality of windings provided in the circumferential direction, an inspection voltage application unit 22 that divides the multiple windings into a first coil group including a pair of first coil portions U1, U3 that are arranged opposite each other along a first opposing axis that passes through the center C of the stator 11, and a second coil group including a pair of second coil portions U2, U4 that are arranged opposite each other along a second opposing axis that passes through the center C and is different from the first opposing axis, and applies an inspection voltage to each coil portion included in each coil group; a shared voltage detection unit 23 that measures the shared voltages in the pair of first coil portions U1 and U3 and the pair of second coil portions U2 and U4 when the test voltage is applied; an angle estimation unit that estimates the angle between the d-axis or q-axis of the rotor and the first opposing shaft or the second opposing shaft; and an eccentricity estimation unit that estimates the amount of eccentricity of the rotor based on the shared voltage and angle.

[0058] The disclosure in Supplementary Note 1 addresses the problem that, in conventional technology, errors in eccentricity estimation occur when the rotor rotation angle changes because the terminal voltage of the winding group changes even if the eccentricity position remains the same. This problem arises because, when the rotor has saliency, the proportion of the magnetic resistance of the air gap, which increases or decreases due to eccentricity, to the total magnetic resistance in the magnetic path including the stator winding changes depending on the rotor rotation angle. As explained with reference to Figure 7, if the rotation angle is not taken into account in eccentricity estimation, an error occurs in the eccentricity estimation due to the inductance change component caused by the rotation angle.

[0059] According to Supplementary Note 1, by providing an angle estimation unit 24 that estimates the angle between the d-axis 31 or q-axis 32 of the rotor 12 and the first opposing shaft or the second opposing shaft, it becomes possible to subtract the inductance change component due to the rotation angle in eccentricity estimation, thereby reducing the eccentricity estimation error.

[0060] [Appendix 2] An eccentricity estimation system (2A) for a rotating electric machine (3) including a rotor (12) having non-uniform magnetic resistance in the circumferential direction and a stator (11) having a plurality of windings in the circumferential direction, an inspection voltage application unit 22 that divides the multiple windings into a first coil group including a pair of first coil portions U1, U3 that are arranged opposite each other along a first opposing axis that passes through the center C of the stator 11, and a second coil group including a pair of second coil portions U2, U4 that are arranged opposite each other along a second opposing axis that passes through the center C and is different from the first opposing axis, and applies an inspection voltage to each coil portion included in each coil group; a shared voltage detection unit 23 that measures the shared voltages in the pair of first coil portions U1 and U3 and the pair of second coil portions U2 and U4 when the test voltage is applied; an angle control unit 24A that controls the angle between the d-axis 31 or q-axis 32 of the rotor 12 and the first opposing shaft or the second opposing shaft to a predetermined angle; and an eccentricity estimation unit that estimates the amount of eccentricity of the rotor based on the shared voltage and angle.

[0061] In a rotating electric machine with salient poles, the d-axis inductance generally has a larger contribution from the air gap than the d-axis inductance. Therefore, as explained with reference to FIG. 7, the q-axis inductance is more sensitive to the increase or decrease in the air gap due to eccentricity. According to Supplementary Note 2, the rotor 12 can be controlled to a rotation angle at which the sensitivity of the inductance to eccentricity is high, thereby improving the accuracy of eccentricity estimation. [Explanation of symbols]

[0062] 2,2A: Eccentricity estimation system 22: Inspection voltage application unit 23: Shared voltage detection unit 24:Angle estimation part 24A: Angle control section 25: Eccentricity estimation part 26: Jumper wire 3: Rotating electric machine 11: Stator 12: Rotor 13: Permanent magnet 14: U phase terminal section 15: Neutral point 161, 162, 163, 164: Leader lines 31:d axis 32:q axis C: Center U1, U2, U3, U4: Coil part V1, V2, V3, V4: Coil part W1, W2, W3, W4: Coil part

Claims

1. An eccentricity estimation system for a rotating electric machine including a rotor having non-uniform magnetic resistance in a circumferential direction and a stator having a plurality of windings provided in the circumferential direction, an inspection voltage application unit (22) that divides the plurality of windings into a first coil group including a pair of first coil portions arranged opposite to each other along a first opposing axis passing through the center of the stator, and a second coil group including a pair of second coil portions (U2, U4) arranged opposite to each other along a second opposing axis passing through the center and different from the first opposing axis, and applies an inspection voltage to each coil portion included in each coil group; a shared voltage detection unit (23) that measures a shared voltage in the pair of first coil portions and a shared voltage in the pair of second coil portions when an inspection voltage is applied; an angle estimation unit (24) that estimates an angle between the d-axis or q-axis of the rotor and the first opposing shaft or the second opposing shaft; an eccentricity estimation unit (25) that estimates the amount of eccentricity of the rotor based on the shared voltage and the angle; An eccentricity estimation system comprising:

2. An eccentricity estimation system (2A) for a rotating electric machine (3) including a rotor (12) having non-uniform magnetic resistance in the circumferential direction and a stator (11) having a plurality of windings provided in the circumferential direction, an inspection voltage application unit (22) that divides the plurality of windings into a first coil group including a pair of first coil portions (U1, U3) arranged opposite to each other along a first opposing axis that passes through the center of the stator, and a second coil group including a pair of second coil portions (U2, U4) arranged opposite to each other along a second opposing axis that passes through the center and is different from the first opposing axis, and applies an inspection voltage to each coil portion included in each coil group; a shared voltage detection unit (23) that measures a shared voltage in the pair of first coil portions and a shared voltage in the pair of second coil portions when an inspection voltage is applied; an angle control unit (24A) that controls the angle between the d-axis or q-axis of the rotor and the first opposing shaft or the second opposing shaft to a predetermined angle; an eccentricity estimation unit (25) that estimates the amount of eccentricity of the rotor based on the shared voltage and the angle; An eccentricity estimation system comprising:

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