Motor system and motor

Abstract

In a motor system provided with a motor (1) and a control unit for controlling the motor, the motor is provided with: a rotor (10) in which a magnetic flux generator for generating magnetic flux is disposed; a stator (12) having a rear yoke (13) disposed so as to face the rotor, and a plurality of teeth (14) protruding from the rear yoke toward the rotor and disposed so as to be spaced apart from each other in the rotation direction of the rotor; a winding (16) wound around the stator; and a plurality of magnetic sensors (17-1-17-6) that are provided in slots (15), which are spaces between adjacent teeth, and that measure the magnetic flux density, the control unit having a calculation unit that determines at least one of the rotation angle and the amount of eccentricity of the rotor on the basis of signals from the plurality of magnetic sensors, and that calculates the amount of eccentricity of the rotor on the basis of the calculated amount of eccentricity. The signal of the magnetic sensor used by the calculation unit is a signal of a magnetic sensor provided in slots in which the windings on both sides have the same phase and are energized in opposite directions.

Description

Technical Field

[0001] The present invention relates to a motor system and a motor that detect at least one of a rotation angle and an eccentricity of a motor using a magnetic sensor. Background Art

[0002] The motor generates torque through the interaction between current and magnetic flux density. In order to detect the rotation angle or eccentricity of the motor, there is a method in which a magnetic flux generator such as a permanent magnet or an excitation winding that generates magnetic flux is arranged on the rotor, and the magnetic flux density from the rotor is measured by a magnetic sensor and used for calculation.

[0003] For example, Patent Document 1 discloses a motor having a rotor on which permanent magnets are arranged and a magnetic sensor, and having a function of detecting the rotation angle of the motor. In the motor disclosed in Patent Document 1, the magnetic sensor is arranged between a plurality of teeth around which windings are wound.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2016-188700 Summary of the invention

[0005] However, according to the motor disclosed in Patent Document 1, the magnetic sensor detects not only the magnetic flux generated by the permanent magnets arranged on the rotor, but also the magnetic flux generated by the winding when power is supplied. Therefore, there is a problem that the signal of the magnetic sensor changes when power is supplied to the winding, and the detection error of the rotation angle or eccentricity may increase.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a motor system capable of reducing a detection error of information of a detection target of at least one of a rotation angle and an eccentricity.

[0007] In order to solve the above-mentioned problems and achieve the purpose, the motor system of the present invention has a motor and a control unit for controlling the motor, and the motor system is characterized in that the motor has: a rotor, which is equipped with a magnetic flux generating body that generates magnetic flux; a stator, which has a back yoke arranged opposite to the rotor, and a plurality of teeth protruding from the back yoke toward the rotor and arranged at intervals in the rotation direction of the rotor; a winding, which is wound on the stator; and a plurality of magnetic sensors, which are arranged in the space between adjacent teeth, i.e., slots, to measure the magnetic flux density, and the control unit has a calculation unit, which calculates at least one of the rotation angle and eccentricity of the rotor based on signals from the plurality of magnetic sensors, and the signals of the magnetic sensors used by the calculation unit are signals of magnetic sensors arranged in slots such that the windings on both sides are of the same phase and are energized in opposite directions.

[0008] Effects of the Invention

[0009] According to the present invention, there is an effect of providing a motor system capable of reducing a detection error of information of a detection target of at least one of a rotation angle and an eccentricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a diagram showing a configuration of a motor system according to the first embodiment.

[0011] Figure 2 It is a diagram showing a cross-sectional structure of the electric motor according to the first embodiment.

[0012] Figure 3 yes Figure 2 A partial enlarged view of .

[0013] Figure 4 It is a diagram showing the structure of the XZ cross section of the electric motor according to the first embodiment.

[0014] Figure 5 This is a diagram showing the correlation between the amount of positional deviation between the rotor and the magnetic sensor in the direction of the rotation axis and the magnitude of the signal detected by the magnetic sensor.

[0015] Figure 6 This is a diagram showing the relationship between the magnitude of the detection signal of the magnetic sensor and the slope of the rotor.

[0016] Figure 7 This is a diagram showing the relationship between the position of the magnetic sensor and the magnetic flux density in the radial direction.

[0017] Figure 8 It is a diagram showing a cross-sectional structure of a motor according to a modification of the first embodiment.

[0018] Fig. 9 It is a diagram showing a cross-sectional structure of a motor according to the second embodiment.

[0019] Fig.10 It is a diagram showing a cross-sectional structure of a motor according to a modification of the second embodiment.

[0020] Fig.11 It is a diagram showing a cross-sectional structure of a motor according to a third embodiment.

[0021] Fig.12 It is a diagram showing a cross-sectional structure of a motor according to a modified example of the third embodiment.

[0022] Fig.13 This is a diagram showing the structure of a control unit according to the fourth embodiment.

[0023] Fig.14 This is a diagram showing an example of the relationship between the amount of current supplied to the winding and the signal of the magnetic sensor.

[0024] Fig.15 yes Fig.13 An explanatory diagram of the correction unit shown. DETAILED DESCRIPTION

[0025] Hereinafter, a motor system and a motor according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0026] Implementation method 1.

[0027] Figure 1 1 is a diagram showing a configuration of a motor system 100 according to Embodiment 1. The motor system 100 includes a motor 1 and a control unit 2. The motor 1 is a device that converts electrical energy into mechanical energy. Specifically, the motor 1 outputs a rotational motion using a force generated by the interaction between a magnetic field and an electric current. The control unit 2 controls the motor 1.

[0028] The motor 1 is provided with a magnetic sensor 17 for measuring magnetic flux density. The magnetic sensor 17 outputs a signal indicating the measured magnetic flux density to the control unit 2. The control unit 2 has a calculation unit 21 for calculating the rotation angle and eccentricity of the motor 1 based on the signal from the magnetic sensor 17. The control unit 2 can control the motor 1 based on the detected rotation angle and eccentricity. Figure 1 17 is represented by one module, but the motor 1 has a plurality of magnetic sensors 17. In addition, here, the control unit 2 is set to detect the rotation angle and the eccentricity, but the control unit 2 detects at least one of the rotation angle and the eccentricity. That is, the control unit 2 may detect only the rotation angle, only the eccentricity, or both the rotation angle and the eccentricity.

[0029] Figure 2 1 is a diagram showing a cross-sectional structure of the motor 1 according to Embodiment 1. When the direction of the rotation axis of the motor 1 is set to the Z-axis direction, Figure 2The XY cross section is shown. The motor 1 has a rotor 10, a permanent magnet 11 arranged on the rotor 10, and a stator 12. The rotor 10 is cylindrical with the Z-axis direction as the longitudinal direction, and the permanent magnet 11 is arranged on the outer circumference. The permanent magnet 11 of the rotor 10 is an example of a magnetic flux generator that generates magnetic flux. In addition to the permanent magnet 11, the magnetic flux generator can also be an excitation winding. Here, the magnetic flux generated by the permanent magnet 11 contributes to the generation of torque of the motor 1, and is also used for the detection of the rotation angle and the eccentricity. Therefore, the increase in the overall volume and mass of the motor 1 can be reduced, and the rotation angle and the eccentricity can be detected. The stator 12 has: a cylindrical back yoke 13, which is arranged opposite to the rotor 10 in a state separated from the rotor 10 by a gap; and a plurality of teeth 14, which protrude from the back yoke 13 toward the rotor 10. The plurality of teeth 14 are arranged at intervals from each other in the circumferential direction. The space between adjacent teeth 14 is called a slot 15.

[0030] The number of teeth 14 and slots 15 of the stator 12 is 12, and the number of poles of the permanent magnet 11 of the rotor 10 is 10. Therefore, the motor 1 has 10 poles and 12 slots.

[0031] In addition, the motor 1 has a winding 16 wound around a plurality of teeth 14, respectively. In addition, the U-phase winding 16 is referred to as 16U or 16U (bar). U (bar) indicates that a bar is marked on U. Below, similarly, the case where a bar is marked on a number is sometimes represented as being marked after the number (bar). Here, the winding 16U (bar) refers to a winding in which the direction of current flow is opposite to that of the winding 16U. Here, the winding 16U is wound in such a manner that when a positive current flows, an outward magnetic flux is generated on the tooth 14 around which the winding 16U is wound, and the winding 16U (bar) is wound in such a manner that when a positive current flows, an inward magnetic flux is generated on the tooth 14 around which the winding 16U (bar) is wound.

[0032] The motor 1 has 12 slots. To generate a 10-pole magnetic field, the motor 1 Figure 2 In the counterclockwise direction from the 3 o'clock direction on the paper, there are winding 16U, winding 16U (horizontal bar), winding 16V (horizontal bar), winding 16V, winding 16W, winding 16W (horizontal bar), winding 16U (horizontal bar), winding 16U, winding 16V, winding 16V (horizontal bar), winding 16W (horizontal bar), and winding 16W.

[0033] The magnetic sensor 17 is a sensor such as a Hall element, which can convert a magnetic field or a magnetic flux density into a voltage for measurement. The motor 1 has six magnetic sensors 17. When distinguishing between the plurality of magnetic sensors 17, a hyphen and a number are added after the reference numeral 17, and the sensors are referred to as magnetic sensors 17-1 to 17-6. The magnetic sensor 17 can be a digital output mode in which the output changes with a threshold as a boundary, or an analog output mode in which the output changes linearly in proportion to the value of the magnetic flux density. In the digital output mode, the range of the rotation angle and the eccentricity can be known, and in the analog output mode, the values ​​of the rotation angle and the eccentricity can be known directly. In addition, in the analog output mode, compared with the digital output mode, the influence of the magnetic flux generated by the energization of the winding 16 will directly appear in the signal of the magnetic sensor 17, which is prone to become a problem. Below, the magnetic sensor 17 is described as an analog output mode. In addition, in the air, the magnetic field is proportional to the magnetic flux density. Hereinafter, the detection object of the magnetic sensor 17 is mainly marked as the magnetic flux density, but it can also be a magnetic field.

[0034] The magnetic sensor 17 is provided in the slot 15 such that the phases of the windings 16 wound on the teeth 14 on both sides are the same and the directions of the current flow are opposite to each other. In other words, the magnetic sensor 17 is provided between the windings 16 which are the same in phase and the directions of the current flow are opposite to each other. Specifically, the magnetic sensor 17-1 is provided between the winding 16U and the winding 16U (horizontal bar). The magnetic sensor 17-2 is provided between the winding 16V and the winding 16V (horizontal bar). The magnetic sensor 17-3 is provided between the winding 16W and the winding 16W (horizontal bar). The magnetic sensor 17-4 is provided between the winding 16U and the winding 16U (horizontal bar). The magnetic sensor 17-5 is provided between the winding 16V and the winding 16V (horizontal bar). The magnetic sensor 17-6 is provided between the winding 16W and the winding 16W (horizontal bar).

[0035] In addition, Figure 2 , six magnetic sensors 17-1 to 17-6 are shown, but if the motor 1 has a plurality of magnetic sensors 17, the number is not particularly limited. In order to calculate the angle using the magnetic sensor 17, it is sufficient to detect the waveform of the magnetic flux density on at least two sinusoidal waves with different phases as the rotor 10 rotates. Therefore, at least two magnetic sensors 17 are required.

[0036] Assuming that the angle of the rotor 10, that is, the rotation angle, is θ, if the information of the waveform X=cosθ and the waveform Y=sinθ can be calculated from the magnetic sensor 17, the rotation angle θ can be calculated using the following equation (1). -1 It means inverse tangent.

[0037] [Formula 1]

[0038]

[0039] The waveforms of cosθ and sinθ can be directly obtained from two magnetic sensors 17 arranged at positions where the electrical phase differs by 90°. In addition, by performing the four arithmetic operations including the three-phase to two-phase conversion described later based on the signals of more than or equal to three magnetic sensors 17, the waveforms of cosθ and sinθ can also be calculated. Moreover, even when only two magnetic sensors 17 are arranged and the electrical phase difference is not 90°, the waveforms of cosθ and sinθ can be obtained by performing four arithmetic operations based on the two signals. For example, waveform X=cosθ and waveform Y'=cos(θ-60°) are obtained. In this case, if the following formula (2) is performed, the waveform Y=sinθ can be obtained.

[0040] [Formula 2]

[0041]

[0042] The windings 16 of the same phase may all be connected in series or partially connected in parallel. If all the windings 16 of the same phase are connected in series, the value of the current flowing in all the windings 16 of the same phase becomes the same. In addition, even if part of the windings 16 of the same phase are connected in parallel, if the current circulating in the parallel circuit is small, the current value flowing in each winding 16 can be regarded as the same. In addition, the connection of the three phases of the U phase, the V phase and the W phase may be a Y connection or a Δ connection.

[0043] Figure 3 yes Figure 2 A partial enlarged view of the Figure 3 The principle of canceling out magnetic flux density generated by energizing the winding 16 when the magnetic sensor 17 is disposed in the slot 15 where the windings 16 wound around the teeth 14 on both sides are in the same phase and energized in opposite directions is explained. Figure 3 The figure shows the situation when a positive current flows in the winding 16U. According to the right-hand screw rule, magnetic flux density is generated in the winding 16U and around the winding 16U (horizontal bar). The magnitude of the generated magnetic flux density is roughly proportional to the current and inversely proportional to the distance from the winding 16. Therefore, the larger the current flowing in the winding 16, or the closer the magnetic sensor 17 is to the winding 16, the greater the influence of the magnetic flux density generated by the winding 16 on the magnetic sensor 17 becomes.

[0044] However, the magnetic sensor 17 is provided in the slot 15 such that the phases of the windings 16 wound on the teeth 14 on both sides are the same and the directions of the current flow are opposite to each other. That is, the phases of the windings 16 on both sides of the magnetic sensor 17 are the same and the directions of the current flow are opposite to each other. Therefore, the magnetic flux density generated in the field where the magnetic sensor 17 is arranged is the magnetic flux density generated by each of the two windings 16 arranged on both sides of the magnetic sensor 17. Specifically, Figure 3 The magnetic sensor 17-1 shown is affected by the magnetic flux 18U generated from the winding 16U and the magnetic flux 18U (horizontal bar) generated from the winding 16U. At this time, when the magnetic sensor 17-1 is arranged at the exact middle position between the winding 16U and the winding 16U (horizontal bar), the magnitude of the magnetic flux 18U and the magnetic flux 18U (horizontal bar) are the same and the direction is opposite in the radius R direction. Therefore, the influence of the winding 16U on the magnetic sensor 17-1 is offset by the influence of the winding 16 (horizontal bar) on the magnetic sensor 17-1. Here, the magnetic sensor 17-1 is described, but the same is true for the other magnetic sensors 17-2 to 17-6. At the position where the magnetic sensors 17-1 to 17-6 are arranged, even if the amount of flux of the winding 16 increases or decreases, the magnetic flux density does not change, and only the magnetic flux from the permanent magnet 11 of the rotor 10 appears. Therefore, the magnetic sensor 17 can detect only the magnetic flux from the permanent magnet 11 of the rotor 10.

[0045] In addition, in the above description, the case where the motor 1 is a radial gap motor in which the rotor 10 and the stator 12 are opposite to each other in the radial direction is described. The same effect is also achieved with respect to the axial gap motor in which the rotor 10 and the stator 12 are opposite to each other in the direction of the rotation axis. In the case of the axial gap motor, the direction of the magnetic flux from the rotor 10 is mainly the direction of the rotation axis. In addition, in the stator 12, the direction of the magnetic flux from the windings 16 on both sides of the magnetic sensor 17 is also mainly the direction of the rotation axis. With respect to the axial gap motor, if the magnetic sensor 17 is arranged between two windings 16 of the same phase and in opposite directions of energization, the magnetic flux from the windings 16 on both sides is also the same in size and in opposite directions and cancels each other out. Therefore, the magnetic sensor 17 can detect only the magnetic flux from the permanent magnet 11 arranged on the rotor 10.

[0046] As described above, the magnetic sensor 17 is arranged in the slot 15 where the phase of the winding 16 wound on the teeth 14 on both sides is the same and the directions of the current are opposite to each other, so there is no need to consider the influence of the winding 16 on the magnetic sensor 17. Therefore, there is no need to increase the distance between the magnetic sensor 17 and the winding 16. Therefore, the magnetic sensor 17 can be arranged near the winding 16. The limited space of the slot 15 can be filled in the winding 16 instead of the space for obtaining the distance between the winding 16 and the magnetic sensor 17, so that the resistance of the winding 16 can be reduced, and the copper loss during operation can be reduced. In order to greatly reduce the influence from the winding, sometimes a permanent magnet dedicated to the detection of the rotation angle and the eccentricity is prepared at a position physically separated from the motor 1 and the winding 16, and the magnetic flux of the permanent magnet dedicated to the detection is detected, but it is not necessary. In addition, as a result, when the output and loss are set to be the same, the size and mass of the motor 1 as a whole can be reduced.

[0047] Figure 4 1 is a diagram showing the structure of the XZ section of the motor 1 involved in the first embodiment. Here, the XZ section is a section including the rotation axis and the radius R direction. Conventionally, in order to reduce the influence of the magnetic flux from the winding 16, there is a method of offsetting the position of the magnetic sensor 17 in the rotation axis direction, that is, the Z axis direction. However, if the position of the magnetic sensor 17 is offset in the rotation axis direction, the size of the magnetic flux 19 from the permanent magnet 11 of the rotor 10 will also decrease, so the SNR (Signal to Noise Ratio) result is difficult to decrease. The magnetic sensor 17 of the motor 1 can be arranged in a position away from the winding 16 in the rotation axis direction, but in Figure 4 Δz≒0 is shown in the figure, and it can be arranged at the center position of the rotor 10 in the direction of the rotation axis. The reason is that, as described above, by arranging the magnetic sensor 17 in the slot 15 where the windings 16 wound on the teeth 14 on both sides are of the same phase and energized in opposite directions, the influence of the windings 16 on both sides is offset regardless of the location in the direction of the rotation axis. Δz represents the position offset of each magnetic sensor 17 from the center position of the rotor 10 in the direction of the rotation axis. Figure 4 Magnetic sensors 17 with Δz≒0, magnetic sensors 17 with Δz<0, and magnetic sensors 17 with Δz>0 are shown in FIG.

[0048] In addition, when the rotor 10 is suspended in the air by magnetic levitation or there is an error in assembly, and when the rotor 10 and the stator 12 vibrate, the relative position of the rotor 10 with respect to the magnetic sensor 17 may be offset in the direction of the rotation axis or the tilt direction. At this time, sometimes at a position axially offset from the permanent magnet 11 of the rotor 10, the magnitude of the signal detected by the magnetic sensor 17 may be greatly different due to the displacement of the rotor 10, the offset of the configuration location of the magnetic sensor 17, etc. When the position of the magnetic sensor 17 is configured at a position axially offset from the rotor 10, if the distance between the rotor 10 and the magnetic sensor 17 increases, the magnitude of the signal of the magnetic sensor 17 decreases, and if the distance between the rotor 10 and the magnetic sensor 71 decreases, the magnitude of the signal of the magnetic sensor 17 increases.

[0049] Figure 5 1 is a diagram showing the correlation between the positional deviation amount Δz in the rotation axis direction between the rotor 10 and the magnetic sensor 17 and the magnitude of the signal detected by the magnetic sensor 17 . Figure 5 The horizontal axis of is the positional offset Δz between the rotor 10 and the magnetic sensor 17 in the direction of the rotation axis. Figure 5 The vertical axis is the magnitude B of the detection signal of the magnetic sensor 17. The magnitude B of the detection signal of the magnetic sensor 17 has a maximum value near Δz = 0, and the change in the magnitude B of the detection signal is small near Δz ≒ 0. In contrast, if the absolute value of the positional offset Δz increases, the change in the magnitude B of the detection signal of the magnetic sensor 17 increases due to a slight change in the value of Δz.

[0050] Figure 6 : is a graph showing the relationship between the magnitude B of the detection signal of the magnetic sensor 17 and the slope Δθ of the rotor 10. When the magnetic sensor 17 is arranged at a position where Δz≒0, even if the rotor 10 is tilted and the value of Δθ changes, the distance between the magnetic sensor 17 and the permanent magnet 11 is almost unchanged, so the magnitude B of the detection signal of the magnetic sensor 17 is also unchanged. On the other hand, when the magnetic sensor 17 is arranged at a position where Δz>0, if the rotor 10 is tilted and the absolute value of Δθ changes, the distance between the magnetic sensor 17 and the permanent magnet 11 changes.

[0051] The motor 1 arranges the magnetic sensor 17 between the windings 16 of the same phase and in opposite directions. If the above conditions are met, the magnetic sensor 17 is arranged near the center position of the rotor 10, that is, Δz≒0, in the direction of the rotation axis of the motor 1, thereby increasing the magnitude of the magnetic flux from the permanent magnet 11 of the rotor 10 and reducing the influence of the magnetic flux from the winding 16. As a result, compared with the prior art in which the magnetic sensor 17 is arranged at a position offset from the center position of the rotor 10 in the direction of the rotation axis, the SNR can be improved step by step. In addition, if the magnetic sensor 17 is arranged near the center part of the direction of the rotation axis of the motor 1, that is, Δz≒0, even if the rotor 10 and the magnetic sensor 17 are relatively offset in the axial direction or the tilt direction, the magnitude B of the detection signal of the magnetic sensor 17 is almost unchanged. Therefore, the magnetic sensor 17 can detect the magnetic flux robustly against the positional offset and vibration of the magnetic sensor 17 and the rotor 10. Furthermore, by arranging a plurality of magnetic sensors 17 at positions where Δz>0 and Δz<0, the influence of magnetic flux from the winding 16 due to energization can be suppressed, and the axial position and the tilt position of the rotor 10 can be detected.

[0052] Figure 7 : is a diagram showing the relationship between the position of the magnetic sensor 17 and the magnetic flux density in the direction of radius R. Figure 7 In FIG. 1 , the magnetic flux density in the direction of radius R when the magnetic sensor 17 is arranged near the rotor 10, that is, near the gap between the rotor 10 and the stator 12, is indicated by a dotted line. Figure 7 In FIG. 1 , the magnetic flux density in the direction of radius R when the magnetic sensor 17 is arranged inside the slot 15 away from the gap is indicated by a solid line. Figure 2 In the inner rotor type in which the rotor 10 is on the inner side of the stator 12, it refers to the positive radius R direction side, and in the outer rotor type in which the rotor 10 is on the outer side of the stator 12, it refers to the negative radius R direction. The closer the magnetic sensor 17 is to the gap, the more magnetic flux it receives from the permanent magnet 11, and the larger the signal obtained becomes. However, the magnetic flux from the permanent magnet 11 contains not only fundamental wave components but also a large amount of harmonic components. Therefore, regarding the signal detected by the magnetic sensor 17, when the magnetic sensor 17 is arranged at a position close to the gap and the signal of the magnetic sensor 17 contains a large amount of harmonic components, as shown in FIG. Figure 7 As shown by the dotted line, it will not become an ideal sine wave and the angle error will increase.

[0053] If the magnetic sensor 17 is arranged away from the gap and in the direction of the inside of the slot 15, that is, on the side of the back yoke 13 compared to the front end of the tooth 14, the fundamental wave component is reduced, but the spatial harmonic component that is the cause of the angle error is greatly reduced. Therefore, the signal detected by the magnetic sensor 17 is close to a sine wave, and the angle error caused by the spatial harmonics from the permanent magnet 11 is reduced. Here, if the magnetic sensor 17 is arranged inside the slot 15, the result is close to the winding 16 of the stator 12, and the magnetic sensor 17 is easily affected by the magnetic flux from the winding 16. However, as described above, if the magnetic sensor 17 is arranged between the windings 16 of the same phase and the directions in which the current is supplied are opposite to each other, the influence of the magnetic flux from one winding 16 can be offset by the influence of the magnetic flux from the other winding 16, so that the increase in the influence of the magnetic flux from the winding 16 can be suppressed. Therefore, by disposing the magnetic sensor 17 inside the slot 15 between the windings 16 of the same phase and energized in opposite directions, it is possible to reduce both the influence of the space harmonics from the permanent magnet 11 and the influence of the magnetic flux from the windings 16 .

[0054] Next, use the formula for 10 poles and 12 slots, and Figure 2 When the magnetic sensors 17 are provided, the signals detected by the magnetic sensors 17 and the subsequent processing method performed by the calculation unit 21 of the control unit 2 using these signals will be described.

[0055] The number of pole pairs is 5. The value of the number of pole pairs, i.e., "5", is larger than "4", which is one third of the number of slots "12", and is smaller than "8", which is two thirds of the number of slots "12".

[0056] Here, the signals of the six magnetic sensors 17 - 1 to 17 - 6 are respectively referred to as S1 to S6. That is, the signal of the n-th magnetic sensor 17 - n is referred to as S n . S n It is expressed by the following formula (3). Here, B0 is the amplitude of the fundamental wave of the magnetic flux from the permanent magnet 11 of the rotor 10 when there is no eccentricity in the radius R direction, p is the number of pole pairs of the permanent magnet 11, θ is the angle of the rotor 10, α n is the angle at which the magnetic sensor 17 is arranged. b is a coefficient indicating the ratio of the third harmonic component to the fundamental wave of the permanent magnet 11, r is the magnitude of the eccentricity of the rotor 10, φ is the direction of the eccentricity of the rotor 10 with the X-axis direction as the reference 0 degree, R n and L n These are magnetic flux densities generated by energizing the windings 16 located adjacent to each other on both sides of the n-th magnetic sensor 17 - n .

[0057] [Formula 3]

[0058]

[0059] If the displacement amount of the rotor 10 in the X direction is x and the displacement amount of the rotor 10 in the Y direction is y, the following relationships between equations (4) and (5) are established between x, y, and r, φ, respectively.

[0060] [Formula 4]

[0061]

[0062] [Formula 5]

[0063]

[0064] exist Figure 2 In the figure, the 3 o'clock direction on the paper is set to 0°, and α1 = 15°, α2 = α1 + 60°, α3 = α1 + 120°, α4 = α1 + 180°, α5 = α1 + 240°, and α6 = α1 + 300° are set. In addition, p = 5. If the relationship between α2 = α5 - 180° and α6 = α3 + 180° is used, S1 to S6 are respectively expressed by the following equations (6) to (11).

[0065] [Formula 6]

[0066]

[0067] [Formula 7]

[0068]

[0069] [Formula 8]

[0070]

[0071] [Formula 9]

[0072]

[0073] [Formula 10]

[0074]

[0075] [Formula 11]

[0076]

[0077] Here, the calculation unit 21 of the control unit 2 calculates the difference between the signals of the pair of magnetic sensors 17, with the two magnetic sensors 17 forming a pair. Specifically, the calculation unit 21 considers the magnetic sensor 17-1 and the magnetic sensor 17-4 as a pair of sensors, the magnetic sensor 17-2 and the magnetic sensor 17-5 as a pair of sensors, and the magnetic sensor 17-3 and the magnetic sensor 17-6 as a pair of sensors.

[0078] S1 to S4 are expressed by the following equation (12), S5 to S2 are expressed by the following equation (13), and S3 to S6 are expressed by the following equation (14).

[0079] [Formula 12]

[0080] S1-S4=2B0[cos p(θ-α1)+b cos3p(θ-α1)]+R1+L1-R4-L4…(12)

[0081] [Formula 13]

[0082] S5-S2=2B0[cos p(θ-α5)+b cos3p(θ-α5)]-R2-L2+R5+L5=2B0[cos[p(θ-α1)-120°]+b cos3p(θ-α1)]-R2-L2+R5+L5…(13)

[0083] [Formula 14]

[0084] S3-S6=2B0[cos p(θ-α3)+b cos3p(θ-α3)]+R3+L3-R6-L6

[0085] =2B0[cos[p(θ-α1)-240°]+b cos3p(θ-α1)]+R3+L3-R6-L6…(14)

[0086] Then, the calculation unit 21 performs three-phase to two-phase conversion on the calculated "S1-S4", "S5-S2", and "S3-S6" as expressed by equation (15).

[0087] [Formula 15]

[0088]

[0089] In equation (15), even if the value of coefficient b representing the ratio of the third harmonic component to the fundamental wave of the permanent magnet 11 is not 0, b is not included in the signal after the three-phase two-phase conversion. Therefore, the difference between the signals of a pair of magnetic sensors 17 can be obtained, and the influence of the third harmonic component can be removed by performing the three-phase two-phase conversion.

[0090] In addition, the windings 16 located on both sides of the magnetic sensor 17 are considered to be of the same phase and are energized in opposite directions. For example, a U-phase winding 16U and a U (horizontal bar) layer winding 16U (horizontal bar) are provided on both sides of the magnetic sensor 17. Here, if the current flowing in the winding 16U is set to i u , set the proportionality coefficient to k, then R1 = ki u , L1=-kiu Therefore, R1+L1=0 holds. Similarly, all magnetic sensors 17 are provided in slots where the windings 16 wound around the teeth 14 on both sides are of the same phase and energized in opposite directions, so R n +L n = 0 holds. At this time, the following equation (16) holds.

[0091] [Formula 16]

[0092]

[0093] Therefore, the calculation unit 21 calculates the arc tangent by substituting the detected signal of the magnetic sensor 17 into the equation (16) to obtain p(θ−α1). Here, if p and α1 are known, the calculation unit 21 can calculate θ.

[0094] That is, the angle information output by the calculation unit 21 is free of the influence of the spatial harmonics of multiples of three from the permanent magnet 11 and the magnetic flux from the winding 16 .

[0095] Next, the calculation method of the eccentricity is described. The magnetic sensors 17 are operated as a pair. Specifically, the operation unit 21 uses the magnetic sensor 17-1 and the magnetic sensor 17-4 as a pair of sensors, the magnetic sensor 17-2 and the magnetic sensor 17-5 as a pair of sensors, and the magnetic sensor 17-3 and the magnetic sensor 17-6 as a pair of sensors.

[0096] S1+S4 is expressed by the following formula (17), S2+S5 is expressed by the following formula (18), and S3+S6 is expressed by the following formula (19).

[0097] [Formula 17]

[0098]

[0099] [Formula 18]

[0100]

[0101] [Formula 19]

[0102]

[0103] Then, the calculation unit 21 performs three-phase to two-phase conversion on the calculated "S1+S4", "S2+S5", and "S3+S6" as expressed by equation (20).

[0104] [Formula 20]

[0105]

[0106] As shown in equation (20), regarding the eccentricity, even if the three-phase to two-phase conversion is performed, the influence of the third harmonic component of the permanent magnet 11 will remain. However, if the magnetic sensor 17 is arranged inside the slot 15, the proportion of the third harmonic can be greatly reduced as described above. n +L n =0 holds true, and if the third harmonic is so small that it can be relatively ignored, equation (20) can be approximated by equation (21).

[0107] [Formula 21]

[0108]

[0109] Since B0cosp(θ-α1) and B0sinp(θ-α1) can be calculated, if they are used as a rotation matrix, a function that does not include θ but includes r and φ can be obtained as shown in the following equation (22).

[0110] [Formula 22]

[0111]

[0112] This is equivalent to the radial position information of the rotor 10. The calculation unit 21 can calculate the eccentricity as described above.

[0113] In addition, the above description is for the case where the number of pole pairs of the permanent magnet 11 is an odd number of 5, but the rotation angle and the eccentricity can also be obtained in the same manner when the number of pole pairs is an even number. However, when the number of pole pairs is an even number, when calculating the angle, the difference between the signals of the pair of magnetic sensors 17 is replaced by the sum of the signals.

[0114] In addition, in the above description, the motor 1 with 10 poles and 12 slots is described, but the number of slots is greater than or equal to 12 times 6, and the number of pole pairs p of the permanent magnet 11 and the number of pole pairs generated by the winding 16 are larger than a value of one-third times the number of slots and smaller than a value of two-thirds times the number of slots. By setting the relationship between the number of slots, the number of pole pairs p of the permanent magnet 11, and the number of pole bodies generated by the winding 16 as described above, it is possible to set the slots 15 such that the windings 16 wound around the teeth 14 on both sides are of the same phase and the directions of energization are opposite to each other. Therefore, the signal of the magnetic sensor 17 used when the calculation unit 21 calculates at least one of the rotation angle and the eccentricity of the motor 1 can be set to the signal of the magnetic sensor 17 set in the slot 15 such that the windings 16 wound around the teeth 14 on both sides are of the same phase and the directions of energization are opposite to each other.

[0115] Figure 8 1 is a diagram showing a cross-sectional structure of a motor 1 - 1 according to a modification of the first embodiment. Figure 8The figure shows an 8-pole 9-slot motor 1-1. Figure 2 The difference between the motor 1 shown in FIG. 1 and FIG. 2 is explained. The motor 1 has 10 poles and 12 slots, while the motor 1-1 has 8 poles and 9 slots, and is different from the motor 1 in this point. That is, the motor 1-1 has a rotor 10 and a stator 12. In addition, the stator 12 of the motor 1-1 has 9 teeth 14, and a winding 16 is wound around each tooth 14. Here, the winding 16 of the motor 1-1 is from Figure 8 The 3 o'clock direction on the paper is in the counterclockwise direction winding 16U, winding 16U (horizontal bar), winding 16V (horizontal bar), winding 16V, winding 16V (horizontal bar), winding 16W (horizontal bar), winding 16W, winding 16W (horizontal bar), winding 16U (horizontal bar). Here, the motor 1-1 has magnetic sensors 17 arranged at three locations: the slot 15 provided between the winding 16U and the winding 16U (horizontal bar), the slot 15 provided between the winding 16V and the winding 16V (horizontal bar), and the slot 15 provided between the winding 16W and the winding 16W (horizontal bar).

[0116] In the motor 1-1, the magnetic sensor 17 is also provided in the slot 15 such that the windings 16 wound around the teeth 14 on both sides are of the same phase and the current is conducted in opposite directions. In addition, the number of pole pairs p of the permanent magnet 11 is 4, which is greater than 3, which is one third of the number of slots 9, and smaller than 6, which is two thirds of the number of slots 9.

[0117] Here, an example of 8 poles and 9 slots is shown, but the number of slots is greater than or equal to 9 which is a multiple of 3, and the number of pole pairs p of the permanent magnet 11 and the number of pole pairs generated by the winding 16 are larger than a value of one third times the number of slots and smaller than a value of two thirds times the number of slots. By setting the relationship between the number of slots, the number of pole pairs p of the permanent magnet 11 and the number of pole pairs generated by the winding 16 as described above, it is possible to provide slots 15 in which the windings 16 wound around the teeth 14 on both sides are of the same phase and the directions of energization are opposite to each other.

[0118] In addition, Figure 2 and Figure 8 , a radial gap motor is shown in which the stator 12 is arranged outside the rotor 10, the stator 12 and the rotor 10 are opposite to each other with a gap surface in the radial direction, but the above-described effect can be obtained even in an outer rotor type in which the stator 12 is arranged inside the rotor 10. In addition, the same effect can be obtained even in an axial gap motor in which the stator 12 and the rotor 10 are opposite to each other with a gap surface in the axial direction.

[0119] In addition, the connection method of the winding 16 of the U phase, V phase and W phase can be Y connection or Δ connection. In addition, whether the winding 16 of the same phase is connected in series or in parallel, the current of approximately the same magnitude will flow in the same phase, so the same effect is obtained. In addition, in embodiment 1, the motor 1 and the motor 1-1 using the winding 16 of the three phases are described, but in the case of using the winding of the two phases or the winding of the four phases or more, if the magnetic sensor 17 is arranged between the windings of the same phase and the directions of the current flow in opposite directions, the same effect as that of embodiment 1 can also be obtained.

[0120] Furthermore, when a plurality of single-phase inverters and windings are used, the same effect can be obtained by arranging magnetic sensors between the single-phase windings.

[0121] As described above, according to the first embodiment, there is provided a motor system 100 including a motor 1 and a control unit 2 for controlling the motor 1. The motor 1 includes a rotor 10 provided with a permanent magnet 11 as a magnetic flux generator that generates magnetic flux, and a stator 12 disposed opposite to the rotor 10. The stator 12 includes a back yoke 13 disposed opposite to the rotor 10, and a plurality of teeth 14 that protrude from the back yoke 13 toward the rotor 10 and are arranged at intervals in the rotation direction of the rotor 10. In addition, the motor 1 includes a winding 16 wound around the stator 12, and a plurality of magnetic sensors 17 disposed in the slots 15, i.e., spaces between adjacent teeth 14, for measuring magnetic flux density. The control unit 2 includes a calculation unit 21 for obtaining at least one of the rotation angle and the eccentricity of the rotor 10 based on the signals of the plurality of magnetic sensors 17. The signals of the magnetic sensors 17 used by the calculation unit 21 are signals of the magnetic sensors 17 disposed in the slots 15 so that the windings 16 on both sides are of the same phase and are energized in opposite directions. By arranging the magnetic sensor 17 in the slot 15 where the windings 16 on both sides are of the same phase and energized in opposite directions, the signal of the magnetic sensor 17 is offset by the influence of one of the windings 16 on both sides even when the windings 16 are energized. Therefore, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0122] In addition, the magnetic sensor 17 is located inside the slot 15, that is, between adjacent teeth 14, and is arranged on the back yoke 13 side in the direction of radius R centered on the rotation axis of the motor 1 compared to the front end of the tooth 14. As a result, the spatial harmonic component can be greatly reduced from the signal of the magnetic sensor 17, and the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced. In addition, in the case of an axial motor, the back yoke 13 side refers to the axial direction, that is, the Z direction.

[0123] In addition, the motor 1 has three groups of a pair of magnetic sensors 17 each including a first sensor and a second sensor, and the calculation unit 21 calculates the sum or difference of the signal of the first sensor and the signal of the second sensor in each group. Thus, the influence of the spatial harmonic component of multiples of 3 from the permanent magnet 11 and the influence of the magnetic flux generated by the energization of the winding 16 are removed from the rotation angle and the eccentricity output by the calculation unit 21. Therefore, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0124] In addition, the number of slots 15 of the motor 1, i.e., the slot number, is "12", which satisfies the condition that it is greater than or equal to 12 which is a multiple of 6. In addition, in the motor 1, the number of pole pairs of the permanent magnet 11 as a magnetic flux generator and the number of pole pairs generated by the winding 16 are "5", which satisfies the condition that it is greater than the value of one-third times the number of slots "12", i.e., "4", and less than the value of two-thirds times the number of slots "12", i.e., "8". By setting the number of slots and the number of pole pairs to satisfy the above conditions, the magnetic sensor 17 can be arranged in the slot 15 in which the windings 16 wound on the teeth 14 on both sides are of the same phase and the directions of energization are opposite to each other. Therefore, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0125] In addition, the motor 1-1 involved in the modified example of embodiment 1 has 8 poles and 9 slots. In this case, the number of slots is "9", which satisfies the condition that it is greater than or equal to 9 times 3. In addition, the number of pole pairs of the permanent magnet 11 and the number of pole pairs generated by the winding 16 are "4", which satisfy the condition that it is greater than the value of "3" which is one-third times the number of slots "9" and smaller than the value of "6" which is two-thirds times the number of slots "9". By setting the number of slots and the number of pole pairs to satisfy the above conditions, it is possible to configure the magnetic sensor 17 in the slot 15 where the windings 16 wound on the teeth 14 on both sides are of the same phase and the directions of energization are opposite to each other. Therefore, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0126] Implementation method 2.

[0127] Fig. 9 1 is a diagram showing a cross-sectional structure of the motor 1-2 involved in the second embodiment. In addition, the difference between the motor 1-2 and the first embodiment is that the motor 1-2 has 16 poles and 18 slots, and two types of windings are wound around each tooth 14. The structure of the motor 1-2 is the same as that of the motor 1 except for the above points. The motor 1-2 has: a rotor 10 having a back yoke 13 and teeth 14; a rotor 10 having a permanent magnet 11; and a magnetic sensor 17, which is arranged in a space between adjacent teeth 14. In addition, the signal of the magnetic sensor 17 is output to the operation unit 21 of the control unit 2 in the same manner as in the first embodiment. Below, the differences from the first embodiment are mainly described.

[0128] The motor 1 - 2 has 18 teeth 14 . A first winding 31 and a second winding 32 are wound around each tooth 14 . Fig. 9 In the example of , the first winding 31 and the second winding 32 are wound in a superimposed manner. Here, the first winding 31 is wound outside the second winding 32. In addition, the rotor 10 has a 16-pole permanent magnet 11. The number of slots 15 of the stator 12 is 18.

[0129] The first winding 31 is wound around the 18 teeth 14 so as to generate a 16-pole magnetic field. Fig. 9 Counterclockwise from 3 o'clock on the paper, they are the first winding 31U, the first winding 31U (horizontal bar), the first winding 31V (horizontal bar), the first winding 31V, the first winding 31V (horizontal bar), the first winding 31W (horizontal bar), the first winding 31W, the first winding 31W (horizontal bar), the first winding 31U (horizontal bar), the first winding 31U, the first winding 31U (horizontal bar), the first winding 31V (horizontal bar), the first winding 31V, the first winding 31V (horizontal bar), the first winding 31W (horizontal bar), the first winding 31W, the first winding 31W (horizontal bar), and the first winding 31U (horizontal bar). The second winding 32 of the motor 1-2 is wound around the 18 teeth 14 in a manner that generates a 14-pole magnetic field. The second winding 32 is wound from Fig. 9 Counterclockwise from the 3 o'clock direction on the paper, they are the second winding 32V, the second winding 32V (horizontal bar), the second winding 32W (horizontal bar), the second winding 32U (horizontal bar), the second winding 32U, the second winding 32V, the second winding 32W, the second winding 32W (horizontal bar), the second winding 32U (horizontal bar), the second winding 32V (horizontal bar), the second winding 32W, the second winding 32U, the second winding 32U (horizontal bar), the second winding 32V (horizontal bar), the second winding 32W (horizontal bar), the second winding 32W, and the second winding 32U.

[0130] The number of pole pairs generated by the second winding 32 is 7, and the number of pole pairs p of the permanent magnet 11 is 8. At this time, the number of pole pairs generated by the second winding 32 satisfies the condition that it is 1 greater or 1 less than the number of pole pairs of the permanent magnet 11. In addition, the number of pole pairs generated by the second winding 32 is greater than 6, which is a value of one third times the number of slots, and is less than 12, which is a value of two thirds times the number of slots.

[0131] The motor 1-2 has six magnetic sensors 17-1 to 17-6. The magnetic sensor 17-1 is arranged between the first winding 31U and the first winding 31U (bar). The magnetic sensor 17-2 is arranged between the first winding 31V and the first winding 31V (bar). The magnetic sensor 17-3 is arranged between the first winding 31W and the first winding 31W (bar). The magnetic sensor 17-4 is arranged between the first winding 31U and the first winding 31U (bar). The magnetic sensor 17-5 is arranged between the first winding 31V and the first winding 31V (bar). The magnetic sensor 17-6 is arranged between the first winding 31W and the first winding 31W (bar).

[0132] In addition, the magnetic sensor 17-1 is arranged between the second winding 32V and the second winding 32V (bar). The magnetic sensor 17-2 is arranged between the second winding 32U and the second winding 32U (bar). The magnetic sensor 17-3 is arranged between the second winding 32W and the second winding 32W (bar). The magnetic sensor 17-4 is arranged between the second winding 32U and the second winding 32U (bar). The magnetic sensor 17-5 is arranged between the second winding 32U and the second winding 32U (bar). The magnetic sensor 17-6 is arranged between the second winding 32W and the second winding 32W (bar).

[0133] In the motor 1-2, the magnetic sensors 17-1 to 17-6 are respectively provided in the slots 15 such that the first windings 31 wound around the teeth 14 on both sides are of the same phase and are energized in opposite directions, and the second windings 32 wound around the teeth 14 on both sides are of the same phase and are energized in opposite directions. Therefore, similarly to the first embodiment, the influence of the magnetic flux of the first winding 31 and the influence of the magnetic flux of the second winding 32 can be reduced at the same time.

[0134] in addition, Fig.10 1 is a diagram showing a cross-sectional structure of a motor 1-3 according to a modified example of the second embodiment. Here, mainly the differences from the motor 1-2 are described. The first winding 31 of the motor 1-3 is wound on the inner side of the second winding 32 in the direction of radius R centered on the rotation axis of the motor 1-3. Even when the first winding 31 and the second winding 32 are wound as described above, the same effect as that of the motor 1-2 can be obtained.

[0135] In addition, if the second winding 32 is Fig. 9When the arrangement in counterclockwise direction at 3 o'clock on the paper is set to be the second winding 32U, the second winding 32V, the second winding 32V (horizontal bar), the second winding 32W (horizontal bar), the second winding 32U (horizontal bar), the second winding 32U, the second winding 32V, the second winding 32W, the second winding 32W (horizontal bar), the second winding 32U (horizontal bar), the second winding 32V (horizontal bar), the second winding 32V, the second winding 32W, the second winding 32U, the second winding 32U (horizontal bar), the second winding 32V (horizontal bar), the second winding 32W (horizontal bar), and the second winding 32W, the above effect cannot be obtained. The configuration of the second winding 32 also takes into account the relationship with the first winding 31, and needs to be designed so that the first winding 31 wound on the teeth 14 on both sides is of the same phase and energized in opposite directions, while the second winding 32 to be wound on the teeth 14 on both sides of the slot 15 is of the same phase and energized in opposite directions.

[0136] As described above, according to Embodiment 2, a method is provided to replace Figure 1 The motor system 100 includes the motor 1-2 instead of the motor 1. The motor system 100 including the motor 1-2 will be described below, but the same also applies to the motor system 100 including the motor 1-3 instead of the motor 1-2. The motor 1-2 includes a rotor 10 having a permanent magnet 11 as a magnetic flux generator that generates magnetic flux, and a stator 12 that is disposed opposite to the rotor 10. The stator 12 includes a back yoke 13 that is disposed opposite to the rotor 10, and a plurality of teeth 14 that protrude from the back yoke 13 toward the rotor 10 and are arranged at intervals in the rotation direction of the rotor 10. In addition, the motor 1 includes a first winding 31 that is wound around the stator 12, and a plurality of magnetic sensors 17 that are provided in the spaces between adjacent teeth 14, i.e., slots 15, and measure magnetic flux density. The control unit 2 includes a calculation unit 21 that obtains at least one of the rotation angle and eccentricity of the rotor 10 based on the signals of the plurality of magnetic sensors 17. The signal of the magnetic sensor 17 used by the calculation unit 21 is the signal of the magnetic sensor 17 provided in the slot 15 such that the first windings 31 on both sides are of the same phase and are energized in opposite directions. By providing the magnetic sensor 17 in the slot 15 such that the first windings 31 on both sides are of the same phase and are energized in opposite directions, even when the first windings 31 are energized, the signal of the magnetic sensor 17 is offset by the influence of one of the first windings 31 on both sides by the influence of the other first winding 31. Therefore, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0137] In the second embodiment, the magnetic sensor 17 is also located inside the slot 15, that is, between adjacent teeth 14, and is arranged on the back yoke 13 side in the direction of radius R centered on the rotation axis of the motor 1 compared to the tip of the tooth 14. As a result, the spatial harmonic component can be greatly reduced from the signal of the magnetic sensor 17, and the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0138] In addition, the motor 1-2 has three groups of a pair of magnetic sensors 17 each including a first sensor and a second sensor, and the calculation unit 21 calculates the sum or difference of the signal of the first sensor and the signal of the second sensor in each group. As a result, the rotation angle and eccentricity output from the calculation unit 21 are free of the influence of the spatial harmonic components of multiples of 3 from the permanent magnet 11 and the influence of the magnetic flux generated by the energization of the first winding 31. Therefore, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0139] In addition, the number of slots 15 of the motor 1-2, i.e., the number of slots, is "18", which satisfies the condition that it is greater than or equal to 12 which is a multiple of 6. In addition, in the motor 1-2, the number of pole pairs of the permanent magnet 11 as a magnetic flux generator and the number of pole pairs generated by the winding 16 are "8", which satisfies the condition that it is greater than the value of "6" which is one-third times the number of slots "18" and smaller than the value of "12" which is two-thirds times the number of slots "18". By setting the number of slots and the number of pole pairs to satisfy the above conditions, the magnetic sensor 17 can be arranged in the slots 15 where the first windings 31 on both sides are of the same phase and the directions of energization are opposite to each other. Therefore, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0140] In addition, according to the second embodiment, the motor 1-2 further includes a second winding 32 wound on the stator 12. The number of pole pairs "7" generated by the second winding 32 satisfies the condition that it is 1 greater than the number of pole pairs "8" of the permanent magnet 11 as a magnetic flux generator, or 1 less than the number of pole pairs "8" of the permanent magnet 11. In addition, the number of pole pairs "7" generated by the second winding 32 satisfies the condition that it is greater than the value "6" which is one-third times the number of slots "18", and is less than the value "12" which is two-thirds times the number of slots "18". By setting the number of slots and the number of pole pairs to satisfy the above conditions, the magnetic sensor 17 can be arranged in the slots 15 such that the second windings 32 on both sides are of the same phase and the directions of energization are opposite to each other. Therefore, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0141] Implementation method 3.

[0142] Fig.111 is a diagram showing a cross-sectional structure of the motor 1-4 according to the third embodiment. The motor 1-4 has two types of windings, namely the first winding 31 and the second winding 32, similarly to the motor 1-2 according to the second embodiment. In the motor 1-2, the first winding 31 and the second winding 32 wound around the teeth 14 on both sides of the slot 15 where the magnetic sensor 17 is arranged have the same phase and are energized in opposite directions. In contrast, in the motor 1-4, the first winding 31 wound around the teeth 14 on both sides of the slot 15 where the magnetic sensor 17 is arranged has the same phase and is energized in opposite directions, and the second winding 32 wound around the teeth 14 on both sides of the slot 15 where the magnetic sensor 17 is arranged has a different phase. In addition, the signal of the magnetic sensor 17 is output to the calculation unit 21 of the control unit 2 in the same manner as in the first embodiment. The following is a specific description.

[0143] The motor 1-4 includes a rotor 10, a permanent magnet 11 disposed on the rotor 10, a stator 12 having a back yoke 13 and teeth 14, and a magnetic sensor 17 disposed in a slot 15, which is a space between adjacent teeth 14. A first winding 31 and a second winding 32 are wound around the teeth 14. The first winding 31 and the second winding 32 are wound in a superimposed manner, and here, the first winding 31 is wound outside the second winding 32. In addition, the rotor 10 has a permanent magnet 11 with 10 poles. The number of slots 15 of the stator 12 is 12.

[0144] The first winding 31 is wound around the twelve teeth 14 so as to generate a 10-pole magnetic field. The second winding 32 is wound around the twelve teeth 14 so as to generate an 8-pole magnetic field. Fig.11 The first winding 31U, the first winding 31U (bar), the first winding 31V (bar), the first winding 31V, the first winding 31W, the first winding 31W (bar), the first winding 31U (bar), the first winding 31U, the first winding 31V, the first winding 31V (bar), the first winding 31W (bar), the first winding 31W. The second winding 32 is from Fig.11 In the counterclockwise direction from the 3 o'clock direction on the paper, there are the second winding 32U, the second winding 32V, the second winding 32W, the second winding 32U, the second winding 32V, the second winding 32W, the second winding 32U, the second winding 32V, and the second winding 32W.

[0145] The number of pole pairs generated by the second winding 32 is 4, and the number of pole pairs of the permanent magnet 11 is 5. At this time, the number of pole pairs generated by the second winding 32 satisfies the condition that it is 1 greater or 1 less than the number of pole pairs of the permanent magnet 11.

[0146] The motor 1-4 has six magnetic sensors 17-1 to 17-6. The magnetic sensor 17-1 is arranged between the first winding 31U and the first winding 31U (bar). The magnetic sensor 17-2 is arranged between the first winding 31V and the first winding 31V (bar). The magnetic sensor 17-3 is arranged between the first winding 31W and the first winding 31W (bar). The magnetic sensor 17-4 is arranged between the first winding 31U and the first winding 31U (bar). The magnetic sensor 17-5 is arranged between the first winding 31V and the first winding 31V (bar). The magnetic sensor 17-6 is arranged between the first winding 31W and the first winding 31W (bar).

[0147] In addition, the magnetic sensor 17-1 is arranged between the second winding 32U and the second winding 32V. The magnetic sensor 17-2 is arranged between the second winding 32W and the second winding 32U. The magnetic sensor 17-3 is arranged between the second winding 32V and the second winding 32W. The magnetic sensor 17-4 is arranged between the second winding 32U and the second winding 32V. The magnetic sensor 17-5 is arranged between the second winding 32W and the second winding 32U. The magnetic sensor 17-6 is arranged between the second winding 32V and the second winding 32W.

[0148] Here, the first windings 31 located on both sides of the magnetic sensor 17 meet the condition that they are of the same phase and are energized in opposite directions, but the second windings 32 located on both sides of the magnetic sensor 17 are of different phases. Therefore, if viewed from a single body, the signal of the magnetic sensor 17 is affected by the energization of the second winding 32. Therefore, the calculation unit 21 of the control unit 2 processes the magnetic sensors 17 as a pair of two, calculates the difference between the two signals of the pair of magnetic sensors 17, and cancels the influence of the second winding 32. Here, the two magnetic sensors 17 with the same combination of the phases of the second windings 32 located on both sides of the magnetic sensor 17 are processed as a pair of magnetic sensors 17.

[0149] For example, the magnetic sensor 17 - 1 and the magnetic sensor 17 - 4 are both disposed between the second winding 32U and the second winding 32V. Here, if the coefficient is k and the U-phase current is i u , set the V phase current to i v , then the influence of the second winding 32 on the magnetic sensor 17-1 is expressed as ki u +ki v Similarly, the influence of the second winding 32 on the magnetic sensor 17-4 is also expressed as ki u +ki vTherefore, by treating the magnetic sensor 17 - 1 and the magnetic sensor 17 - 4 as a pair and calculating the difference between the signal of the magnetic sensor 17 - 1 and the signal of the magnetic sensor 17 - 4 , the influence of the second winding 32 is canceled, and only the magnetic flux component of the permanent magnet 11 of the rotor 10 can be extracted.

[0150] Similarly, the magnetic sensor 17-2 and the magnetic sensor 17-5 are both arranged between the second winding 32W and the second winding 32U. In addition, the magnetic sensor 17-3 and the magnetic sensor 17-6 are both arranged between the second winding 32V and the second winding 32W. Therefore, the magnetic sensor 17-2 and the magnetic sensor 17-5 are processed as a pair of two, and the magnetic sensor 17-3 and the magnetic sensor 17-6 are processed as a pair of two, thereby canceling the influence of the second winding 32.

[0151] Fig.12 1 is a diagram showing a cross-sectional structure of a motor 1-5 according to a modification of the third embodiment. The structure of the motor 1-5 is the same as that of the motor 1-4 except that the method of winding the first winding 31 and the second winding 32 on the teeth 14 is different. The first winding 31 of the motor 1-5 is wound on the inner side of the second winding 32 in the direction of radius R centered on the rotation axis of the motor 1-5. When the first winding 31 and the second winding 32 are wound as described above, the magnetic sensors 17 are treated as a pair of two, thereby obtaining the same effect as that of the motor 1-4.

[0152] As described above, according to Embodiment 3, a method is provided to replace Figure 1The motor system 100 includes the motor 1-4 instead of the motor 1. The motor system 100 including the motor 1-4 will be described below, but the same also applies to the motor system 100 including the motor 1-5 instead of the motor 1-4. The motor 1-4 includes: a rotor 10 having a permanent magnet 11 as a magnetic flux generator that generates magnetic flux; and a stator 12 that is arranged opposite to the rotor 10. The stator 12 includes: a back yoke 13 that is arranged opposite to the rotor 10; and a plurality of teeth 14 that protrude from the back yoke 13 toward the rotor 10 and are arranged at intervals in the rotation direction of the rotor 10. In addition, the motor 1 includes: a first winding 31 that is wound around the stator 12; and a plurality of magnetic sensors 17 that are provided in the spaces between adjacent teeth 14, i.e., slots 15, and measure the magnetic flux density. The control unit 2 includes a calculation unit 21 that obtains at least one of the rotation angle and the eccentricity of the rotor 10 based on the signals of the plurality of magnetic sensors 17. The signal of the magnetic sensor 17 used by the calculation unit 21 is the signal of the magnetic sensor 17 provided in the slot 15 such that the first windings 31 on both sides are of the same phase and are energized in opposite directions. The magnetic sensor 17 is provided in the slot 15 such that the first windings 31 on both sides are of the same phase and are energized in opposite directions. Thus, even when the first windings 31 are energized, the signal of the magnetic sensor 17 is offset by the influence of one of the first windings 31 on both sides by the influence of the other first winding 31. Therefore, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0153] In the third embodiment, the magnetic sensor 17 is also located inside the slot 15, that is, between the adjacent teeth 14, and is arranged on the back yoke 13 side in the direction of the radius R centered on the rotation axis of the motor 1 compared to the tip of the tooth 14. As a result, the spatial harmonic component can be greatly reduced from the signal of the magnetic sensor 17, and the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0154] In addition, the motor 1-4 has three groups of a pair of magnetic sensors 17 each including a first sensor and a second sensor, and the calculation unit 21 calculates the sum or difference of the signal of the first sensor and the signal of the second sensor in each group. As a result, the rotation angle and eccentricity output from the calculation unit 21 are free of the influence of the spatial harmonic components of multiples of 3 from the permanent magnet 11 and the influence of the magnetic flux generated by the energization of the first winding 31. Therefore, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0155] In addition, the number of slots 15 of the motor 1-4, i.e., the number of slots, is "12", which satisfies the condition that it is greater than or equal to 12 which is a multiple of 6. In addition, in the motor 1-4, the number of pole pairs of the permanent magnet 11 as a magnetic flux generator and the number of pole pairs generated by the winding 16 are "5", which satisfies the condition that it is greater than the value of one-third times the number of slots "12", i.e., "4", and is smaller than the value of two-thirds times the number of slots "12", i.e., "8". By setting the number of slots and the number of pole pairs to satisfy the above conditions, the magnetic sensor 17 can be arranged in the slots 15 where the first windings 31 on both sides are of the same phase and the directions of energization are opposite to each other. Therefore, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0156] In addition, according to the second embodiment, the motor 1-4 further includes a second winding 32 wound around the teeth 14. The number of pole pairs "4" generated by the second winding 32 satisfies the condition that the number of pole pairs "5" generated by the second winding 32 is greater than the number of pole pairs "5" of the permanent magnet 11 as a magnetic flux generator by 1, or is less than the number of pole pairs "5" of the permanent magnet 11 by 1. In addition, the phases of the second windings 32 on both sides of the slot 15 provided with the magnetic sensor 17 are different from each other. The calculation unit 21 calculates the sum or difference of the signal of the first sensor, which is one of the plurality of magnetic sensors 17 included in the motor 1-4, and the signal of the second sensor arranged between the second windings 32 of the same combination of phases as the combination of phases of the second windings 32 on both sides of the slot 15 provided with the first sensor, thereby being able to cancel the influence of the magnetic flux from the second winding 32 based on the signal of the magnetic sensor 17. Therefore, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0157] Implementation method 4.

[0158] Fig.13 1 is a diagram showing a configuration of a control unit 2-1 according to Embodiment 4. The control unit 2-1 includes a calculation unit 21, a correction unit 22, and a storage unit 23. In addition, here, the signal of the magnetic sensor 17 disposed in the motor 1 is input to the control unit 2-1, but the signal input to the control unit 2-1 may be the signal of the magnetic sensor 17 disposed in any one of the motors 1-1 to 1-5.

[0159] The correction unit 22 has a function of correcting the influence on the signal of the magnetic sensor 17 caused by the change in the amount of energization to the windings 16 located on both sides of the magnetic sensor 17 .

[0160] The storage unit 23 stores the amount of change in the signal of the magnetic sensor 17 corresponding to the amount of energization. The amount of change is calculated based on the signal of the magnetic sensor 17 actually detected when the amount of energization to the winding 16 is changed.

[0161] Fig.141 is a diagram showing an example of the relationship between the amount of current flowing through the winding 16 and the signal of the magnetic sensor 17 . Fig.14 The horizontal axis is the current i flowing in the winding 16. n Current i n The n may be any phase of the winding 16 disposed on both sides of the magnetic sensor 17, that is, the U, V, and W phases, or may be a value obtained by performing four arithmetic operations on a plurality of currents of the three phases. Fig.14 The vertical axis is the signal S of the magnetic sensor 17 n Signal S n The n in may be a sensor number or a value obtained by performing four arithmetic operations on the signals of a plurality of magnetic sensors 17. The intercept on the vertical axis is a term contributed by the rotor 10. If the rotor 10 rotates, this value changes.

[0162] Ideally, even if the amount of current flowing to the windings 16 on both sides of the magnetic sensor 17 changes, the influence of the windings 16 on both sides of the magnetic sensor 17, the influence from one winding 16 and the influence from the other winding 16 cancel each other out, and the signal of the magnetic sensor 17 and the current i n However, in reality, due to the asymmetry caused by the difference in the winding expansion of the winding 16 on both sides of the magnetic sensor 17, the configuration deviation of the magnetic sensor 17, etc., the current i n The effect of is not offset but remains in small amounts. Fig.14 As shown, sometimes the signal of the magnetic sensor 17 changes depending on the amount of current flow. As described above, this relationship is different for each individual of the motor 1 due to the asymmetry of the winding 16, the configuration deviation of the magnetic sensor 17, etc. The magnetic sensor 17 is arranged in the slot 15 where the windings 16 located on both sides are of the same phase and the directions of current flow are opposite to each other. This can greatly reduce the influence of the current flow to the winding 16 on the magnetic sensor 17, but the influence of the current flow caused by the asymmetry of the winding 16, the configuration deviation of the magnetic sensor 17, etc., will remain in a small amount. The correction unit 22 corrects the influence of the current flow caused by the asymmetry of the winding 16, the configuration deviation of the magnetic sensor 17, etc. through subsequent processing.

[0163] Fig.15 yes Fig.13 The correction unit 22 is an explanatory diagram of the correction unit 22 shown in FIG. The correction unit 22 corrects the signal S of the magnetic sensor 17. n Perform correction and output the corrected signal S n '. For example, according to Fig.14 The current i shown n and the signal S of the magnetic sensor 17 n The relationship between the current i n and signal S nWhen the linearity between n =S n '+k n i n Here, S n ' is the signal S output by the magnetic sensor 17 n Among the terms that rotor 10 contributes to, Fig.14 In the , it is equivalent to the intercept. k n i n is the current i of stator 12 n Contribute to the project. Fig.14 In the equation, the coefficient k n Equivalent to the slope. Coefficient k n For example, it can be the above R n +L n In an ideal situation, the coefficient k n =0.

[0164] according to Fig.14 The calibration unit 22 can obtain the coefficient k by using the least square method, for example, based on the actual measurement results shown in FIG. n In addition, based on the results obtained under only two conditions (S n1 ,i n1 ) and (S n2 ,i n2 ) vs (S n1 -S n2 ) / (i n1 -i n2 ) to calculate the coefficient k n .

[0165] If the correction unit 22 can obtain the coefficient k n , then by n '=S n -k n i n " is calculated, so that the signal of the magnetic sensor 17 can be corrected. Therefore, the correction unit 22 can correct the signal of the magnetic sensor 17 based on the information representing the relationship between the amount of current flow and the amount of change in the signal of the magnetic sensor 17 stored in the storage unit 23. n , for the corrected signal S n 'Calculate and output to the calculation unit 21.

[0166] In addition, in the above, Fig.14 As shown, the current i n and the signal S of the magnetic sensor 17 nThe relationship between is described by a linear function, but is not limited to a linear function, and a quadratic function may be used. In addition, even if the correction unit 22 is omitted, the same effect as that of the first embodiment can be obtained, so the correction unit 22 may be omitted.

[0167] As described above, the control unit 2-1 according to the fourth embodiment includes: a storage unit 23 that stores the relationship between the amount of energization and the amount of change in the signal of the magnetic sensor 17, which is obtained based on the signal of the magnetic sensor 17 obtained when the amount of energization of the winding 16 is changed; and a correction unit 22 that corrects the signal of the magnetic sensor 17 based on the relationship between the amount of energization and the amount of change in the signal of the magnetic sensor 17 stored in the storage unit 23. Here, the information indicating the relationship between the amount of energization and the amount of change in the signal of the magnetic sensor 17 may be, for example, a coefficient k n , or it may be the change amount of the signal of the magnetic sensor 17 corresponding to each amount of energization. By having the above-mentioned structure, even if the signal of the magnetic sensor 17 sometimes changes according to the change of the amount of energization to the winding 16, by correcting the signal of the magnetic sensor 17, the detection error of the information of the detection object of at least one of the rotation angle and the eccentricity can be reduced.

[0168] also, Figure 1 The control unit 2 and Fig.13 The control units 2-1 shown are each implemented by a processing circuit. The processing circuit may be dedicated hardware or a control circuit using a CPU (Central Processing Unit). The dedicated hardware used to implement the control units 2, 2-1 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof.

[0169] In the case where the above-mentioned processing circuit is implemented by a control circuit using a CPU, the control circuit can have a processor and a memory. The processor is a CPU, which is also called a processing device, a computing device, a microprocessor, a microcomputer, a DSP (Digital Signal Processor), etc. The memory is, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), an EEPROM (registered trademark) (Electrically EPROM), a magnetic disk, a floppy disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disk), etc.

[0170] When the processing circuit is realized by the control circuit, the processor reads out and executes a program corresponding to the processing of each component stored in the memory. In addition, the memory is also used as a temporary storage in each processing executed by the processor.

[0171] The configuration described in the above embodiment is merely an example, and may be combined with other known technologies, the embodiments may be combined with each other, and part of the configuration may be omitted or changed without departing from the gist.

[0172] For example, in the above embodiment, the winding 16, the first winding 31, and the second winding 32 are wound around the teeth 14, but they may be wound around the stator 12, for example, around the back yoke 13. Even when wound around the back yoke 13, the winding 16, the first winding 31, and the second winding 32 are wound around the teeth 14 in a manner such that they are located on both sides of the slot 15, for example, in the circumferential direction in which the teeth 14 are arranged.

[0173] Description of the label

[0174] 1. 1-1 to 1-5 electric motors, 2. 2-1 control unit, 10 rotor, 11 permanent magnet, 12 stator, 13 back yoke, 14 teeth, 15 slots, 16 windings, 17. 17-1 to 17-6 magnetic sensors, 18U, 19 magnetic flux, 21 calculation unit, 22 correction unit, 23 storage unit, 31 first winding, 32 second winding, 100 electric motor system.

Claims

1. A motor system comprising a motor and a control unit for controlling the motor, The motor system is characterized in that The electric motor has: a rotor provided with a magnetic flux generating body for generating magnetic flux; a stator having a back yoke disposed opposite to the rotor, and a plurality of teeth protruding from the back yoke toward the rotor and arranged at intervals in the rotation direction of the rotor; a winding wound around the stator; and A plurality of magnetic sensors are disposed in the spaces between adjacent teeth, i.e., slots, to measure the magnetic flux density. The control unit includes a calculation unit that obtains at least one of a rotation angle and an eccentricity of the rotor based on signals from the plurality of magnetic sensors. The signal of the magnetic sensor used in the calculation unit is a signal of the magnetic sensor provided in the slots so that the windings on both sides are of the same phase and current is supplied in opposite directions to each other.

2. The electric motor system according to claim 1, characterized in that The magnetic sensor is located inside the slot and is disposed on the back yoke side relative to the front end of the tooth.

3. The electric motor system according to claim 1, characterized in that The motor has three sets of a pair of magnetic sensors each including a first sensor and a second sensor. The calculation unit calculates the sum or difference between the signal of the first sensor and the signal of the second sensor in each group.

4. The electric motor system according to claim 1, characterized in that The number of slots, i.e. the number of slots, is greater than or equal to 9 which is a multiple of 3, The number of pole pairs of the magnetic flux generator and the number of pole pairs generated by the winding are larger than a value of one third of the number of slots and smaller than a value of two thirds of the number of slots.

5. The electric motor system according to claim 1, characterized in that The number of slots, i.e. the number of slots, is greater than or equal to 12 which is a multiple of 6, The number of pole pairs of the magnetic flux generator and the number of pole pairs generated by the winding are larger than a value of one third of the number of slots and smaller than a value of two thirds of the number of slots.

6. The electric motor system according to claim 1, characterized in that The motor further includes a second winding wound around the stator. The number of pole pairs generated by the second winding is one greater than the number of pole pairs of the magnetic flux generator, or one less than the number of pole pairs of the magnetic flux generator. The signal of the magnetic sensor used by the calculation unit is a signal of the magnetic sensor provided in the slots so that the second windings on both sides are of the same phase and are energized in opposite directions to each other.

7. The electric motor system according to claim 1, characterized in that The motor further includes a second winding wound around the stator. The number of pole pairs generated by the second winding is one greater than the number of pole pairs of the magnetic flux generator, or one less than the number of pole pairs of the magnetic flux generator. The second windings on both sides of the slot in which the magnetic sensor is provided have different phases from each other, The calculation unit calculates the sum or difference between the signal of one of the multiple magnetic sensors possessed by the motor, namely, the first sensor, and the signal of the second sensor arranged between the second windings of the same combination of phases as the combination of phases of the second windings on both sides of the slot in which the first sensor is provided, thereby canceling the influence of the magnetic flux from the second winding.

8. The electric motor system according to claim 1, characterized in that The control unit also has: a storage unit that stores information indicating a relationship between the energization amount and a change amount of the signal of the magnetic sensor, obtained from the signal of the magnetic sensor when the energization amount of the winding is changed; and A correction unit corrects the signal of the magnetic sensor based on the relationship between the amount of energization and the amount of change in the signal of the magnetic sensor indicated by the information stored in the storage unit.

9. An electric motor, characterized in that: have: a rotor provided with a magnetic flux generating body for generating magnetic flux; a stator having a back yoke disposed opposite to the rotor, and a plurality of teeth protruding from the back yoke toward the rotor and arranged at intervals in the circumferential direction; A winding wound around the stator; as well as A plurality of magnetic sensors are disposed in the spaces between adjacent teeth, i.e., the slots. The windings of all the plurality of magnetic sensors provided on both sides are of the same phase and are energized in the slots in directions opposite to each other.

10. The electric motor according to claim 9, characterized in that It also has a second winding wound around the stator, The number of pole pairs generated by the second winding is one greater than the number of pole pairs of the magnetic flux generator, or one less than the number of pole pairs of the magnetic flux generator. The number of pole pairs generated by the second winding is greater than the number of slots, i.e., a value one-third of the number of slots, and less than a value two-thirds of the number of slots. All of the plurality of magnetic sensors are provided in the second windings on both sides so that the second windings are of the same phase and current is supplied to the slots in directions opposite to each other.

11. The electric motor according to claim 9, characterized in that It also has a second winding wound around the stator, The number of pole pairs generated by the second winding is one greater than the number of pole pairs of the magnetic flux generator, or one less than the number of pole pairs of the magnetic flux generator. The magnetic sensor includes a first sensor and a second sensor as a pair of sensors. All of the pair of sensors are provided in the slots of the second windings on both sides so that the phases thereof are different from each other. In each of the pair of sensors, a phase group of the second winding located on both sides of the first sensor and a phase group of the second winding located on both sides of the second sensor are the same.

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