Redundant rotary transformer and electric power steering device equipped with the same

Abstract

The present invention relates to a redundant rotary transformer, comprising: a rotary transformer body, comprising a rotor, a stator opposite to the rotor and having Ns (Ns is an integer greater than or equal to 2) teeth (T) arranged in a circumferential direction, an excitation winding (R) and two-phase output windings (Sa, Sb) wound on the stator; an excitation circuit for supplying power to the excitation winding (R); and an angle calculation unit for calculating a rotation angle based on a signal from the two-phase output windings (Sa, Sb), wherein the stator is divided into M pieces in the circumferential direction to form M tooth blocks, and a redundant system of N (N is an integer greater than or equal to 2 and M≥N) systems is formed based on the M tooth blocks, the sum of the division angles of each system is 360 / N degrees, the excitation circuit and the angle calculation unit are independently provided for each system, and at both ends of each tooth block, the number of turns of the excitation winding (R) of the teeth located at both ends is reduced so that the change in the gap magnetic flux density becomes gentle.

Description

Technical Field

[0001] The present application relates to a redundant rotary transformer and an electric power steering device equipped with the redundant rotary transformer. Background Art

[0002] Among resolvers that utilize a change in magnetic permeability in an air gap between a rotor and a stator, a multi-system resolver having two sets of field windings connected to different field circuits, that is, a so-called redundant resolver, is known.

[0003] For example, Patent Document 1 discloses that, in a redundant resolver having two field windings, one resolver stator is divided in the circumferential direction to reduce the axial dimension, and the divided stators are divided into a first system and a second system for redundancy.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 4157930

[0007] Patent Document 2: Japanese Patent Application Publication No. 2009-222435 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] However, in Patent Document 1, since teeth around which field windings of different systems are wound are adjacent to each other, magnetic interference occurs between the different systems, which causes a problem in that the angle detection accuracy deteriorates.

[0010] In order to suppress the deterioration of angle detection accuracy caused by magnetic interference in such a redundant rotary transformer, two rotary transformers having two excitation windings connected to different excitation circuits stacked in two stages in the axial direction are disclosed, with only the first output winding wound on one rotary transformer and only the second output winding wound on the other rotary transformer (for example, Patent Document 2).

[0011] However, in Patent Document 2, since two resolvers are stacked in two stages via a shaft, there is a problem that the axial dimension is twice as large as that of a single-system resolver.

[0012] The present application discloses a technology for solving the above-mentioned problems, and its object is to provide a redundant resolver with high angle detection accuracy without increasing the size.

[0013] Technical means for solving technical problems

[0014] The redundant rotary transformer disclosed in the present application includes: a rotary transformer body, the rotary transformer body having a rotor having Nx (Nx is a natural number) salient poles, a stator opposite to the rotor and having Ns (Ns is an integer greater than or equal to 2) teeth arranged in the circumferential direction, and an excitation winding and a two-phase output winding wound on the teeth; an excitation circuit, the excitation circuit supplies power to the excitation winding; and an angle calculation unit, the angle calculation unit calculates the rotation angle of a rotating body mounted with the rotor based on a signal from the two-phase output winding, the redundant rotary transformer is characterized in that the stator is divided into M pieces in the circumferential direction to form M tooth blocks, and N (N is an integer greater than or equal to 2 and M≥N) redundant systems are formed based on the M tooth blocks, the sum of the division angles of each of the systems is 360 / N degrees, the excitation circuit and the angle calculation unit are independently provided for each of the systems, and the change of the gap magnetic flux density becomes gentle at both ends of each of the tooth blocks.

[0015] Effects of the Invention

[0016] According to the redundant resolver disclosed in the present application, the change in the gap magnetic flux density becomes gentle at both ends of each tooth block, so the electrical angle second-order component superimposed on the output signal can be reduced and the angle detection accuracy can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram showing an example in which the redundant resolver according to the first embodiment is mounted on a rotating electrical machine.

[0018] Figure 2 It is a diagram showing the configuration of a redundant resolver according to the first embodiment.

[0019] Figure 3 It is a cross-sectional view showing a resolver body of the redundant resolver according to the first embodiment.

[0020] Figure 4 It is a cross-sectional view of a stator of the redundant resolver according to the first embodiment.

[0021] Figure 5A This is a diagram showing the number of turns of the field winding of the redundant resolver according to the first embodiment.

[0022] Figure 5B FIG. 1 is a diagram showing the number of turns of an exciting winding of a redundant resolver as a comparative example.

[0023] Figure 6 : is a diagram showing the relationship between the phase difference between the first output signal and the second output signal in the redundant resolver and the phase difference between the excitation signal of the first system and the excitation signal of the second system.

[0024] Figure 7 : is a diagram showing the relationship between the angle error (electrical angle second-order component) in the redundant resolver and the phase difference between the excitation signal of the first system and the excitation signal of the second system.

[0025] Figure 8 1 is a diagram showing waveforms of a first system excitation signal and a second system excitation signal of the redundant resolver according to the first embodiment.

[0026] Fig. 9 2 is a diagram illustrating an output signal waveform of the first system.

[0027] Fig.10 2 is a diagram illustrating an output signal waveform of the second system.

[0028] Fig.11 This is a diagram showing changes in the electrical angle second-order component superimposed on the output signal with respect to the number of turns of the field winding of the teeth located at both ends of the first system tooth block in the redundant resolver according to the first embodiment.

[0029] Fig.12 1 is a diagram showing the direction of magnetic flux interlinked with the teeth of the redundant resolver according to the first embodiment.

[0030] Fig.13 It is a diagram showing the conditions of Examples and Comparative Examples.

[0031] Fig.14 1 is a diagram showing the effect of reducing the electrical angle second-order component superimposed on the output signal of the redundant resolver according to the first embodiment.

[0032] Fig.15 : is a graph showing the effect of reducing the angle error of the redundant resolver according to the first embodiment.

[0033] Fig.16 It is a cross-sectional view of a stator of a redundant resolver according to the second embodiment.

[0034] Fig.17 This is a diagram showing changes in the electrical angle second-order component superimposed on the output signal with respect to the tooth width at both ends of the first system tooth block in the redundant resolver according to the second embodiment.

[0035] Fig.18 : is a graph showing the effect of reducing the angle error of the redundant resolver according to the second embodiment.

[0036] Fig.19 It is a cross-sectional view of a stator of a redundant resolver according to the third embodiment.

[0037] Fig. 20 It is a cross-sectional view of a stator of a redundant resolver according to the fourth embodiment.

[0038] Fig.21 This is a schematic configuration diagram of an electric power steering device according to a fifth embodiment. DETAILED DESCRIPTION

[0039] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or corresponding parts.

[0040] Implementation method 1.

[0041] Hereinafter, the redundant resolver according to the first embodiment will be described.

[0042] Figure 1 : This is a diagram showing an example of installing the redundant rotary transformer involved in Implementation Example 1 on a rotary motor. In addition, although the example of installation on the shaft of the rotary motor is shown, if it is the rotating shaft of the rotating part (rotating body) of various devices, the installation object is not limited to the rotary motor. In the figure, the redundant rotary transformer 100 is installed on the shaft 22 which is the rotating shaft of the rotary motor 21. The redundant rotary transformer 100 includes a rotary transformer body 1 as a sensor and a control circuit 7 for controlling it. The rotary transformer body 1 includes a pair of stators 3 and a rotor 2, and the winding 4 is wound on the stator 3. The rotor 2 is connected to the rotating part of the rotary motor 21 via the shaft 22. The control circuit 7 includes an excitation circuit 6 that applies an AC voltage to the excitation winding described later in the winding 4 and excites it, and an angle calculation unit 5 that calculates the rotation angle based on the signal waveform of the output winding described later in the winding 4.

[0043] Figure 2 : is a diagram showing the structure of the redundant rotary transformer involved in Embodiment 1. In the figure, the redundant rotary transformer 100 includes a rotary transformer 100a of the first system and a rotary transformer 100b of the second system, and an example of a dual system is shown here. The rotary transformer 100a of the first system and the rotary transformer 100b of the second system have a first output winding Sa, a second output winding Sb, and an excitation winding R as windings 4a and 4b, respectively. The first output winding Sa and the second output winding Sb are connected to the angle calculation unit 5a and 5b, and the excitation winding R is connected to the excitation circuit 6a and 6b. In this way, the angle calculation unit 5a, 5b and the excitation circuit 6a, 6b are provided in each system and are independent of each other, thereby ensuring redundancy.

[0044] Figure 3 yes Figure 1A cross-sectional view of the rotary transformer body 1 taken along line X-X in the figure. In the figure, the winding 4 is wound around each tooth T of the stator 3 having a yoke Y and teeth T. The rotor 2 having a salient pole portion 2p is mounted on the shaft 22. In the first embodiment, the number Ns of teeth T of the stator 3 of the redundant rotary transformer is 12, and the number Nx of salient poles of the rotor is set to 5. The number of salient poles is also called the shaft angle multiplier.

[0045] Figure 4 is from Figure 3 The figure without the rotor 2 and the shaft 22 is equivalent to a cross-sectional view of the stator 3, and is a figure showing a part of the structure of the first system and the second system rotary transformers 100a and 100b. As described above, the number Ns of teeth T of the stator 3 of the redundant rotary transformer is 12. If each tooth T is set as teeth T1 to T12 in the clockwise direction, it is divided into two in the circumferential direction into the first system teeth consisting of teeth T1 to T6, and the second system teeth consisting of teeth T7 to T12. The first system teeth constitute the rotary transformer 100a of the first system, and the second system teeth constitute the rotary transformer 100b of the second system, and the two constitute a redundant rotary transformer of the dual system.

[0046] Next, the winding 4 of each tooth T will be described.

[0047] A winding group consisting of a one-phase excitation winding R and two-phase output windings Sa and Sb is wound on each tooth T. That is, the excitation windings R1 to R6 of the first system, the first output windings Sa1 to Sa6 of the first system, and the second output windings Sb1 to Sb6 of the first system are wound on the teeth T1 to T6 of the first system. Similarly, the excitation windings R7 to R12 of the second system, the first output windings Sa7 to Sa12 of the second system, and the second output windings Sb7 to Sb12 of the second system are wound on the teeth T7 to T12 of the second system.

[0048] The first system excitation windings R1 to R6 and the second system excitation windings R7 to R12 are connected to the first system excitation circuit 6a and the second system excitation circuit 6b via excitation terminals (not shown) provided at an extension portion (not shown) of the rotary transformer, respectively.

[0049] The first system's first output windings Sa1 to Sa6 and the first system's second output windings Sb1 to Sb6 are connected to the first system angle calculation unit 5a via output terminals (not shown) provided at the extension of the rotary transformer. The second system's first output windings Sa7 to Sa12 and the second system's second output windings Sb7 to Sb12 are connected to the second system angle calculation unit 5b via output terminals (not shown) provided at the extension of the rotary transformer. The first system angle calculation unit 5a and the second system angle calculation unit 5b calculate the first system detection angle θ1 and the second system detection angle θ2 of the rotor 2 based on the output signals output from the first and second phase output windings, respectively, and output them (see Figure 2 ).

[0050] When focusing on tooth T1, the excitation winding R1 is first wound, followed by the first output winding Sa1 and the second output winding Sb1. That is, the structure is to wind the excitation winding first, and then wind the two-phase output winding from above. The winding order of the first output winding Sa1 and the second output winding Sb1 of the two phases is not limited to this, and any one of them can be wound first. In addition, sometimes a tooth is provided, which is not wound around the output winding of any phase of the two-phase output winding. The stator core and windings including the teeth are insulated by insulating paper, coating, resin, etc. (not shown). Although tooth T1 has been described, the windings are also wound on the other teeth T2 to T12 in the same way.

[0051] The excitation windings R1 to R6 of the first system are connected in series, the first output windings Sa1 to Sa6 of the first system are connected in series, and the second output windings Sb1 to Sb6 of the first system are connected in series. Similarly, the excitation windings R7 to R12 of the second system are connected in series, the first output windings Sa7 to Sa12 of the second system are connected in series, and the second output windings Sb7 to Sb12 of the second system are connected in series.

[0052] In addition, here, the windings are connected in series in the order of teeth T1 to T6 and teeth T7 to T12, but the same effect can be obtained even if the tooth at the start of winding is any tooth Ti in each system and the teeth are connected in series in sequence from adjacent teeth.

[0053] In addition, although the one-phase excitation winding and the two-phase output windings are arranged and wound in the circumferential direction, the present invention is not limited thereto and the same effect can be obtained by arranging them in the radial direction or changing the winding order for each tooth.

[0054] Next, the numbers of turns of the first system field winding and the second system field winding of the redundant resolver according to the first embodiment will be described. Figure 5A is a diagram showing the distribution of windings in the redundant resolver according to the first embodiment. Figure 5B : is a diagram showing the distribution of windings in a comparative example. In the figure, the number of excitation windings is standardized by amplitude, and the number of turns of the excitation windings wound on the first system teeth and the second system teeth are continuously shown. For the excitation winding of the rotary transformer, a winding direction (+) and a winding direction (-) are defined. In the redundant rotary transformer in the present embodiment 1, the winding direction (+) and the winding direction (-) of the excitation winding are alternately arranged. (+) and (-) represent the mutually different winding polarities of the windings. If the winding direction (+) is used to represent the direction of the winding of a certain coil, the coil wound in the reverse direction is represented by the winding direction (-). The absolute value of the number of turns in the winding direction (+) is the same as the number of turns in the winding direction (-). Therefore, the spatial order Ne of the excitation winding is 6. That is, if the number of turns in the winding direction (+) is set to +X turns, the number of turns in the winding direction (-) is -X turns. In addition, here, it is assumed that the winding direction (+) and the winding direction (-) are alternately wound, and the spatial order of the excitation winding is 6, but it is not limited to this, and other winding configurations can also be used, such as a winding configuration in which the spatial order of the excitation winding is 3 and the winding direction (+) and the winding direction (-) are arranged every two teeth.

[0055] In addition, Figure 5B In the comparative example of , the number of turns in all teeth T1 to T12 of the first system tooth block and the second system tooth block is the same. Figure 5A In the redundant rotary transformer according to the first embodiment shown, the number of turns of the field winding wound on the teeth T1, T6 and the teeth T7, T12 located at both ends of the first system tooth block and the second system tooth block is smaller than the number of turns of the field winding wound on the other teeth, that is, the teeth T2, T3, T4, T5 and T8, T9, T10, T11 not located at both ends. The desired number of turns in the first embodiment will be described later.

[0056] As described above, in the redundant rotary transformer involved in the present embodiment 1, the excitation circuit 6a of the first system that provides the excitation signal to the excitation windings R1 to R6 of the first system and the excitation circuit 6b of the second system that provides the excitation signal to the excitation windings R7 to R12 of the second system are independent of each other, thereby ensuring redundancy. However, since they are independent of each other, it is difficult to synchronize the excitation signal of the first system with the excitation signal of the second system. Since there are manufacturing deviations in, for example, microcomputers constituting the excitation circuit 6a of the first system and the excitation circuit 6b of the second system, even if the frequencies of the excitation signal of the first system and the excitation signal of the second system are designed to be the same, they will not be completely consistent, resulting in a slight difference. As a result, the difference between the excitation signal of the first system and the excitation signal of the second system is not constant but changes with time, which affects other systems.

[0057] Figure 6 In the case of Figure 5B In the comparative example of the rotary transformer with the same number of turns, when the excitation circuit 6a of the first system and the excitation circuit 6b of the second system are independent, the horizontal axis is set to the phase difference between the excitation signal of the first system and the excitation signal of the second system, and the vertical axis is set to the deviation of the phase difference between the first output signal of the first system and the second output signal of the first system from 90°. When the phase difference between the first output signal of the first system and the second output signal of the first system is 90°, that is, when both the horizontal axis and the vertical axis are 0, the angle detection can be performed with the highest accuracy. In addition, as the phase difference between the excitation signal of the first system and the excitation signal of the second system becomes larger, it can be seen that the phase difference between the first output signal of the first system and the second output signal of the first system deviates from 90°. Although in Figure 6 , the phase difference of the output signal of the first system is shown in FIG. 1 , but the same phenomenon occurs in the phase difference of the output signal of the second system.

[0058] Figure 7 In the same conditions as above, i.e. for Figure 5B In the comparative example, in the case where the number of turns of the rotary transformer is independent of the first system excitation circuit 6a and the second system excitation circuit 6b, Figure 6 Similarly, the horizontal axis is set to the phase difference between the excitation signal of the first system and the excitation signal of the second system, and the vertical axis is set to the difference between the true value of the angle of the magnetic pole of the rotating motor and the detection angle of the redundant rotary transformer, that is, the electrical angle second-order component of the angle error. It can be seen that as the phase difference between the excitation signal of the first system and the excitation signal of the second system increases, the electrical angle second-order component of the angle error increases. When the excitation signal of the first system and the excitation signal of the second system have a phase difference, the phase difference between the first output signal and the second output signal is not 90°, resulting in the second-order component of the electrical angle of the angle error becoming larger. Since the angle error becomes the cause of the torque ripple, in order to obtain a rotating motor with small torque ripple and high performance, it is necessary to reduce the angle error of the rotary transformer. However, in the redundant rotary transformer in which the excitation circuit of the first system and the excitation circuit of the second system are independent and cannot be synchronized, there is a problem of deterioration of the angle detection accuracy during use. In addition, in Figure 7 , even the second-order component of the electrical angle of the angle error detected in either the first system or the second system shows the same behavior.

[0059] As can be seen from the above, in the redundant resolver according to the present embodiment, since the first system excitation circuit 6 a and the second system excitation circuit 6 b are independent, ensuring redundancy and the possibility of worsening the angle detection error have the opposite effects.

[0060] In the redundant resolver according to the first embodiment, since the first system excitation circuit and the second system excitation circuit are independent of each other, excitation signals of different frequencies can be supplied from the respective excitation circuits to the corresponding excitation windings. Figure 8 The first system excitation signal and the second system excitation signal of the redundant resolver according to Embodiment 1 are shown. The frequency f1 of the first system excitation signal is 10 kHz, and the frequency f2 of the second system excitation signal is 20 kHz. The vertical axis is normalized by the amplitude of the voltage of the excitation signal.

[0061] In addition, the angle calculation units 5a and 5b have the function of removing the frequency components of other systems. That is, the components generated by the excitation signal of the second system are removed from the first output signal of the first system and the second output signal of the first system, and only the components generated by the excitation signal of the first system are taken out. In addition, the components generated by the excitation signal of the first system are removed from the first output signal of the second system and the second output signal of the second system, and only the components generated by the excitation signal of the second system are taken out. The method of removing the frequency components of other systems is described below.

[0062] Fig. 9 : is a diagram illustrating the waveform of the output signal of the first system, and shows the waveforms of the output signal of the first system, the excitation signal of the first system, and the excitation signal of the second system in order from the top. The output signal of the first system is originally a waveform of the frequency f1 corresponding to the excitation signal of the first system, but becomes a waveform after the component of the frequency f2 of the excitation signal of the second system is added. As shown in the figure, +A and -A of the excitation signal of the first system correspond to the positive peak and negative peak of the signal respectively, but since the excitation signal components +Bn and +Bn of the second system are added respectively, it can be seen that the output signal of the first system becomes a waveform distorted from a sine wave. Therefore, if the output signal of the first system is sampled with a period of 1 / f1 and an inverse tangent operation is directly performed, an error caused by the component of the excitation signal frequency f2 of the second system will occur. Therefore, the output signal of the first system is sampled with 2 / f1 and is set to {(A+Bn)-(-A+Bn)] / 2. As a result, only the component A of the excitation signal frequency f1 of the first system can be extracted, and the component Bn of the excitation signal frequency f2 of the second system can be removed, which can improve the detection accuracy of the rotation angle.

[0063] Fig.10This is a diagram illustrating the waveform of the output signal of the second system, and shows the waveforms of the output signal of the second system, the excitation signal of the second system, and the excitation signal of the first system in order from the top. The output signal of the second system is originally a waveform of the frequency f2 corresponding to the excitation signal of the second system, but it becomes a waveform after the component of the frequency f1 of the excitation signal of the first system is added. As shown in the figure, +B, -B, +B, and -B of the excitation signal of the second system correspond to the positive peak and negative peak of the signal respectively, but since the excitation signal components +An1, +An2, -An1, and -An2 of the first system are added respectively, the output signal of the second system becomes a waveform distorted from a sine wave. Therefore, if the output signal of the second system is sampled with a period of 1 / f2 and the arc tangent operation is directly performed, an error caused by the component of the excitation signal frequency f1 of the first system will occur. Therefore, the output signal of the second system is sampled with 2 / f2 and is set to {(B+An1)+(B-An1)-(-B+An2)-(-B-An2)]} / 4. Thus, only the component B of the excitation signal frequency f2 of the second system can be extracted, and the component An of the excitation signal frequency f1 of the first system can be removed, thereby improving the detection accuracy of the rotation angle.

[0064] like Figure 3 and Figure 4 As shown, in the redundant rotary transformer in the present embodiment 1, the system is different for each half cycle of the stator. Furthermore, an excitation signal of a different frequency is provided for each system, and the influence of the excitation signal of other systems is removed in each angle calculation unit. As a result, the first system and the second system are in an independent state, that is, if the first system is focused on, the excitation signal of the second system is not applied to the excitation winding of the first system wound on the teeth of the first system, and the second system becomes the same physical state as when a fault such as a broken wire occurs. On the contrary, if the second system is focused on, the first system becomes the same physical state as when a fault such as a broken wire occurs. This suggests an advantage that by providing excitation signals of different frequencies from each other from independent excitation circuits, a signal that does not affect the signals of other systems can be obtained.

[0065] As described above, in view of the problems and features caused by the independence of the first system excitation circuit 6 a and the second system excitation circuit 6 b in the redundant resolver according to the first embodiment, the effects of the first embodiment will be described in comparison with a comparative example.

[0066] Fig.11 It means in Figure 5AA graph showing the relationship between the number of turns at both ends of the first system tooth block and the ratio of the second-order component of the electrical angle to the fundamental wave of the first output signal. The horizontal axis is the ratio of the number of turns of the exciting winding wound around the teeth (teeth T1, T6) at both ends of the first system tooth block to the number of turns of the exciting winding wound around the teeth (teeth T2, T3, T4, T5) that are not at both ends of the first system tooth block. Let this ratio be A. The vertical axis represents the ratio of the second-order component of the electrical angle to the fundamental wave of the first output signal of the first system. On the horizontal axis, A = 1 means that all the teeth (teeth T1 to T6) within the first system tooth block have the same number of turns (corresponding to Figure 5B comparative example), and the vertical axis is normalized by the value when A = 1.

[0067] Focusing on A = 1 on the horizontal axis, when the number of turns of the teeth (teeth T1, T6) at both ends of the first system tooth block is reduced, that is, when A is decreased, the ratio of the second-order component of the electrical angle to the fundamental wave of the first output signal decreases. If the superimposed ratio of the second-order component of the electrical angle becomes smaller, the angle detection error is reduced. However, if the number of turns is significantly reduced such that A is less than 2 / 7, it will result in an increase in the superimposed ratio of the second-order component of the electrical angle compared to when all the teeth in the first system tooth block have the same number of turns, i.e., A = 1. That is, when 2 / 7 < A < 1, the second-order component of the electrical angle superimposed on the output signal can be made less than that in the comparative example in terms of the number of turns. In addition, according to the drawing, when A = 2 / 3, the second-order component of the electrical angle superimposed on the output signal can be made minimum (about 1 / 3 of that when A = 1).

[0068] Next, use Fig.12 to explain the effect of reducing the number of turns of the exciting windings of the teeth at both ends within the tooth blocks of each system.

[0069] Fig.12: is a diagram showing the direction of the magnetic flux interlinked with each tooth of the first system tooth block of the present embodiment 1. In the figure, as can be seen from the arrows, the teeth T2, T3, T4, and T5 of the first system tooth block are respectively affected by two adjacent teeth. On the other hand, the teeth T1 and T6 located at both ends of the first system tooth block are respectively affected by only one of the two adjacent teeth, that is, the magnetic flux of the adjacent teeth T2 and T5 belonging to the first system tooth block. As described above, in the redundant rotary transformer of the present embodiment 1, the number of turns of the excitation winding wound on the teeth located at both ends of the first system tooth block is less than the number of turns of the excitation winding wound on the other teeth of the first system tooth block. Therefore, the magnetomotive force of the teeth T1 and T6 located at both ends of the first system tooth block becomes weak, and the change of the gap magnetic flux density at both ends of the first system tooth block becomes gentle compared with the comparative example having the same number of windings up to the teeth T1 and T6 located at both ends, so that the electrical angle second-order component superimposed on the output signal is reduced. Although not shown in the figure, the second system tooth block is also similarly located. The magnetomotive force of the teeth T7 and T12 located at the two ends of the second system tooth block becomes weaker, and the change of the gap flux density at the two ends of the second system tooth block becomes gentle compared to the comparative example having the same number of windings up to the teeth T7 and T12 located at the two ends, so that the second-order component of the electrical angle superimposed on the output signal is reduced.

[0070] like Fig.11 As shown in FIG. 1 , when the turns ratio of the teeth at the two end portions becomes smaller, the magnetomotive force of the teeth at the two end portions is weakened as described above, so the electrical angle second-order component superimposed on the output signal decreases. However, when A becomes less than 2 / 7, the teeth at the two end portions do not fully function as stators, so the effect of easing the change of the gap magnetic flux density at the two end portions decreases, and the electrical angle second-order component increases again.

[0071] Next, an example of the effect of the first embodiment is described.

[0072] Fig.14 is a diagram showing an example of the effect of the redundant resolver according to the first embodiment, and is a diagram comparing Fig.13 The following is a graph showing the ratio of the electrical angle second-order component to the fundamental wave of the output signal of Example 1 and Comparative Examples 1 and 2 under the conditions shown. First, the conditions are explained. Fig.13 As shown, the redundant rotary transformer of Example 1 has first and second system gear blocks, which respectively constitute the rotary transformer 100a of the first system and the rotary transformer 100b of the second system. The excitation circuits 6a and 6b of each rotary transformer are independent, and the frequency f1 of the excitation signal of each first system is 10kHz, and the frequency f2 of the excitation signal of the second system is 20kHz. Fig.13In the embodiment 1, the number of turns of the teeth at both ends of each system is a turn ratio A=2 / 3. Although both comparative examples 1 and 2 are redundant rotary transformers having rotary transformers of two systems, the number of turns of all teeth is the same, that is, A=1. In comparative example 1, the excitation circuits of the two systems are independent, and similarly to implementation example 1, the frequency f1 of the excitation signal of the first system is 10kHz, and the frequency f2 of the excitation signal of the second system is 20kHz. In comparative example 2, at a time point when the excitation circuits are independent but the phase difference is 0°, the frequency of the excitation signal to the rotary transformers of the two systems is 10kHz. In addition, in embodiment 1 and comparative example 1, the frequency components of other systems are removed in the angle calculation unit.

[0073] Fig.14 It is for Fig.13 The figure compares the ratio of the second-order component of the electrical angle to the fundamental wave of the first output signal of the first system under the three conditions shown. First, comparing Comparative Examples 1 and 2, in Comparative Example 1, in which excitation signals of different frequencies are provided from two independent excitation circuits and the frequency components of other systems are removed in the angle calculation unit, the second-order component of the electrical angle increases by about 1.4 times compared with Comparative Example 2 in which the phase difference between the two excitation circuits is 0°. The increase in the second-order component of the electrical angle of the output signal causes the increase in the first-order and third-order components of the electrical angle. The increase in the first-order component and the third-order component of the electrical angle of the angle error, which is the difference between the true value of the angle and the detection angle of the redundant rotary transformer, leads to a decrease in the angle detection accuracy.

[0074] On the other hand, in Example 1, the number of turns of the teeth located at both ends of each system is the turn ratio A = 2 / 3, and as described above, the change in the gap magnetic flux density at both ends of the first system tooth block becomes gentle. According to this effect, the electrical angle second-order component in the output signal is reduced not only compared with Comparative Example 1, but also compared with Comparative Example 2 in which the phase difference of the excitation circuit is 0°.

[0075] Fig.15 FIG. 1 is a graph comparing the angle errors of the first-order component and the third-order component of the electrical angle under the conditions of Example 1 and Comparative Example 2. Fig.15 , the first-order component of the electrical angle is normalized to represent the value of the comparative example 2. In the embodiment 1, it can be seen that the first-order component and the third-order component of the electrical angle are improved compared with the comparative example 2, and the angle error is reduced.

[0076] In the above Fig.14 and Fig.15 In the description, the effects of the present embodiment 1 are described with a focus on the first system, but since the same physical phenomenon also occurs in the second system, the description is omitted.

[0077] As described above, according to the redundant resolver related to Embodiment 1, since the stator is divided in the circumferential direction and the resolvers of each system that make up the redundant resolver are composed of the tooth blocks of each system, the resolver body does not become large-sized. Also, the exciting circuits of each system are independently configured, and the number of turns of the exciting winding wound around the teeth at both ends of the tooth blocks of each system is made less than the number of turns of the exciting winding wound around the teeth other than those at both ends. By setting the ratio A of the two to be in the range of 2 / 7 < A < 1, the second-order electrical angle component superimposed on the output signal is reduced compared to the case where the number of turns of the teeth in the system is the same, and the angle detection accuracy is improved.

[0078] In addition, in Embodiment 1 compared with Comparative Examples 1 and 2, exciting signals of different frequencies are provided from two independent exciting circuits, and the frequency components of other systems are removed in the angle operation unit. However, as in Comparative Example 2, the frequencies can be made the same in the two independent exciting circuits, and the frequency components of other systems can be removed in the angle operation unit. Due to the effect of reducing the change in the air-gap flux density by reducing the windings at both ends of the tooth blocks in Embodiment 1, the second-order electrical angle component is reduced compared to Comparative Example 2.

[0079] In addition, in the first-system tooth block and the second-system tooth block, if the number of turns of the teeth not located at both ends of the tooth blocks of each system is the same within the tooth blocks of each system, they can also be different for each system. The number of turns of the exciting windings in the both ends and the teeth other than the both ends can be set so that the change in the air-gap flux density becomes gentle at the both ends for each system.

[0080] Embodiment 2.

[0081] In the above Embodiment 1, the number of exciting windings wound around the teeth at both ends of the tooth blocks of each system is reduced, and the second-order electrical angle component superimposed on the output signal is reduced to make the change in the air-gap flux density gentle at both ends. In this Embodiment 2, the same effect is achieved by changing the widths of the teeth at both ends of the tooth blocks of each system.

[0082] Hereinafter, the redundant resolver related to this Embodiment 2 will be described with reference to the drawings.

[0083] Fig.16: is a cross-sectional view of the stator 3 of the redundant rotary transformer in the second embodiment, and is a diagram showing a part of the structure of the rotary transformers 100a and 100b of the first system and the second system. The structure of the tooth blocks of each system, the winding of each excitation winding, each first output winding, and each second output winding are the same as those in the first embodiment, and the description thereof is omitted. In the stator 3 of the redundant rotary transformer in the second embodiment, the teeth T1 and T6 located at both ends of the tooth block of the first system are thinner than the teeth T2, T3, T4, and T5 not located at both ends. As shown in the figure, if the width of each tooth is set to W Ti (i is the tooth number), and taking tooth T4 as an example of a tooth not located at both ends, then W T1 <W T4 , W T6 <W T4 .

[0084] Similarly, the widths of the teeth T7 and T12 located at both ends of the second system tooth block are thinner than the widths of the teeth T8, T9, T10, and T11 not located at both ends. As shown in the figure, if tooth 9 is taken as an example as a tooth not located at both ends, then W T7 <W T9 , W T12 <W T9 .

[0085] Fig.17 The graph shows the relationship between the width of the teeth located at both ends of the first system tooth block and the ratio of the electrical angle second-order component to the fundamental wave of the first output winding. The horizontal axis is the width W of the teeth (teeth T1 and T6) located at both ends of the first system tooth block. Ti (i=1, 6) and the width W of the teeth (teeth T2, T3, T4, T5) that are not at both ends of the first system gear block Ti (i=2, 3, 4, 5). This ratio is set to B. The vertical axis represents the ratio of the electrical angle second-order component to the fundamental wave of the first output winding of the first system. On the horizontal axis, B=1 means that all the teeth (teeth T1 to T6) in the first system tooth block have the same width, and the vertical axis is normalized to the value when B=1.

[0086] exist Fig.17In [the above], if we focus on B = 1 and reduce the widths of the teeth (teeth T1 and T6) at both ends of the first system tooth block, that is, if B is reduced, the ratio of the second-order component of the electrical angle to the fundamental wave of the first output signal decreases. If the superimposed ratio of the second-order component of the electrical angle becomes smaller, the angle detection error decreases. However, if the width is significantly reduced such that B is less than 7 / 9, the effect of making the change in the magnetic flux density at both ends milder becomes smaller, and the superimposed ratio of the second-order component of the electrical angle will increase compared to when all the teeth in the first system tooth block are the same, i.e., B = 1. That is, when 7 / 9 < B < 1, the second-order component of the electrical angle superimposed on the output signal can be made smaller than the width in the comparative example. According to the drawings, the second-order component of the electrical angle superimposed on the output signal can also be made minimum when B = 5 / 6.

[0087] Fig.18 It is a diagram showing an example of the effect of the redundant resolver according to Embodiment 2.

[0088] In Example 2, Fig.13 Under the conditions shown, the windings of the teeth at both ends are set to have the same number as the windings of the teeth not at both ends, similar to Comparative Example 2, but the widths of the teeth at both ends are set to be smaller than the widths of the teeth not at both ends (B = 5 / 6). Fig.18 It is a diagram comparing the angle errors for the first-order component and the third-order component of the electrical angle under the conditions of this Example 2 and Comparative Example 2, expressed by normalizing with the value of the first-order component of the electrical angle in Comparative Example 2. It can also be seen in Example 2 that both the first-order component and the third-order component of the electrical angle are improved compared to Comparative Example 2, and the angle error decreases.

[0089] This is the same as described in Embodiment 1. The widths of the teeth at both ends of the first system tooth block are smaller than the widths of the other teeth in the first system tooth block, and are in the range of 7 / 9 < B < 1. Therefore, the magnetomotive forces of the teeth T1 and T6 at both ends of the first system tooth block become weaker, and compared to Comparative Example 2 where the teeth T1 and T6 at both ends have the same width, the change in the air-gap magnetic flux density at both ends of the first system tooth block becomes milder, and thus the second-order component of the electrical angle superimposed on the output signal decreases. Moreover, the first-order component and the third-order component of the electrical angle also decrease, and the angle error becomes smaller.

[0090] In the above Fig.17 and Fig.18 the effects of this Embodiment 2 have been described focusing on the first system. However, since the same physical phenomena also occur in the second system, the description is omitted.

[0091] As described above, according to the redundant resolver related to Embodiment 2, the same effects as those of Embodiment 1 are achieved. That is, the widths of the teeth at both ends of the tooth blocks in each system are made smaller than the widths of the teeth not at the ends. By setting the ratio B between the two to be in the range of 7 / 9 < B < 1, compared with the case where the widths of the teeth in the system are the same, the second-order electrical angle component superimposed on the output signal is reduced, and the angle detection accuracy is improved.

[0092] In addition, in Embodiment 2 compared with Comparative Example 2, excitation signals of different frequencies are provided from two independent excitation circuits, and the frequency components of other systems are removed in the angle calculation unit. However, as in Comparative Example 2, the frequencies can be made the same in the two independent excitation circuits, and the frequency components of other systems are not removed in the angle calculation unit. Due to the effect of reducing the change in the air-gap flux density by reducing the widths of the teeth at the both ends of the tooth block in Embodiment 2, the second-order electrical angle component is reduced compared with Comparative Example 2.

[0093] In addition, in the first-system tooth block and the second-system tooth block, if the widths of the teeth not at the both ends of the tooth blocks in each system are the same within the tooth blocks of each system, they can also be different for each system. The widths of the both ends and the teeth other than the both ends can be set so that the change in the air-gap flux density becomes gentle at the both ends for each system.

[0094] Embodiment 3.

[0095] In the above Embodiment 1, the number of turns of the excitation windings wound around the teeth at the both ends of the tooth blocks in each system is reduced. In Embodiment 2, the second-order electrical angle component superimposed on the output signal is reduced by changing the widths of the teeth at the both ends of the tooth blocks in each system so that the change in the air-gap flux density at the both ends becomes gentle. In this Embodiment 3, the same effect is achieved by increasing the air-gap length between the teeth at the both ends of the tooth blocks in each system and the rotor.

[0096] Hereinafter, the redundant resolver related to this Embodiment 3 will be described with reference to the drawings.

[0097] Fig.19: is a cross-sectional view of the stator 3 of the redundant rotary transformer in the third embodiment, and is a diagram showing a part of the structure of the rotary transformers 100a and 100b of the first system and the second system. The structure of the tooth blocks of each system, the winding of each excitation winding, each first output winding, and each second output winding are the same as those of the first and second embodiments, and the description is omitted. In the stator 3 of the redundant rotary transformer in the third embodiment, the front end portions of the teeth T1 and T6 located at both ends of the tooth block of the first system are located on the outer peripheral side of the front end portions of the teeth T2, T3, T4, and T5 not located at both ends. Therefore, the gap length between the teeth T1 and T6 located at both ends of the tooth block of the first system and the rotor is greater than the gap length between the teeth T2, T3, T4, and T5 not located at both ends and the rotor.

[0098] exist Fig.19 In the figure, circle C is represented by a single dotted line. r The dotted line circle C represents the trajectory of the salient pole portion 2p when the rotor rotates. T Connect the faces of the teeth that are not located at both ends that are opposite to the rotor. As shown in the figure, if the gap length between each tooth and the rotor is set to D Ti (i is the tooth number), and as a tooth not located at both ends, if tooth T2 is taken as an example, then D T1 >D T2 , D T6 >D T2 In addition, D T2 The gap length between the teeth not located at the two ends and the rotor is represented by the length from circle C T The radius of circle C minus r The value obtained by the radius.

[0099] Similarly, the front end portions of the teeth T7 and T12 located at both ends of the second system tooth block are located on the outer peripheral side of the front end portions of the teeth T8, T9, T10, and T11 not located at both ends. Therefore, the gap length between the teeth T7 and T12 located at both ends of the second system tooth block and the rotor becomes greater than the gap length between the teeth T8, T9, T10, and T11 not located at both ends and the rotor. As shown in the figure, if the tooth T10 is taken as an example as the tooth not located at both ends, D T7 >D T10 , D T12 >D T10 .

[0100] In the redundant rotary transformer in the third embodiment, the gap length of the teeth T1 and T6 located at both ends of the first system tooth block is greater than the gap length of the other teeth T2, T3, T4, and T5, so the magnetomotive force is weakened, and the change of the gap magnetic flux density at both ends of the first system tooth block becomes gentle, so that the effect of reducing the second-order component of the electrical angle superimposed on the output signal and reducing the first-order component and the third-order component of the electrical angle of the angle error can be obtained. In addition, the gap length of the teeth T7 and T12 located at both ends of the second system tooth block is greater than the gap length of the other teeth T8, T9, T10, and T11, so the magnetomotive force is weakened, and the change of the gap magnetic flux density at both ends of the second system tooth block becomes gentle, so that the effect of reducing the second-order component of the electrical angle superimposed on the output signal and reducing the first-order component and the third-order component of the electrical angle of the angle error can be obtained.

[0101] As described above, according to the redundant resolver involved in the third embodiment, the same effects as those of the first and second embodiments are achieved. That is, by making the gap length of the teeth located at both ends of the tooth block of each system larger than the gap length of the teeth not located at both ends, the electrical angle second-order component superimposed on the output signal is reduced compared to the case where the gap lengths of the teeth in the system are the same, and the angle detection accuracy is improved.

[0102] In addition, embodiments 1 to 3 may be combined in the tooth blocks of each system in such a manner that the change in the gap magnetic flux density at both ends is moderated. For example, in the tooth blocks of each system, within the range that the change in the gap magnetic flux density at both ends is moderated, the width of the teeth located at both ends may be reduced compared to the teeth not located at both ends of the tooth blocks of each system, and the number of turns of the excitation winding may be reduced. For example, in the tooth blocks of each system, within the range that the change in the gap magnetic flux density at both ends is moderated, the width of the teeth located at both ends may be reduced compared to the teeth not located at both ends of the tooth blocks of each system, and the number of turns of the excitation winding may be reduced and the gap length may be increased.

[0103] In addition, in Embodiments 1 to 3, the first system teeth composed of teeth T1 to T6 constitute the first system tooth block, and the second system teeth composed of teeth T7 to T12 constitute the second system tooth block. The first system tooth block and the second system tooth block may be formed as one piece, or both may be formed as one piece. Alternatively, they may be formed as one piece by a manufacturing process such as forming them as one piece separately and then integrating them. In addition, the tooth blocks of each system may be formed by connecting a yoke to each sheet or a stack thereof having teeth T and a yoke Y.

[0104] In addition, in Embodiments 1 to 3, an example in which the number Ns of the teeth T of the stator 3 is 12 and the number Nx of the salient poles of the rotor is 5 is shown, but the present invention is not limited to this.

[0105] Implementation method 4.

[0106] Hereinafter, a redundant resolver according to the fourth embodiment will be described with reference to the drawings.

[0107] In the above-mentioned first to third embodiments, an example in which the teeth ( T1 to T12 ) of the stator are divided into two in the circumferential direction is shown, but the present invention is not limited to this.

[0108] Fig. 20 This is a cross-sectional view of the stator of the redundant rotary transformer involved in the present embodiment 4. The number of teeth Ns of the stator of the rotary transformer involved in the present embodiment 4 is 12, and the axial angle multiple Nx of the rotor is 5. The teeth (T1~T12) of the stator are divided into four parts in the circumferential direction, and are divided into the first tooth block of the first system, the first tooth block of the second system, the second tooth block of the first system, and the second tooth block of the second system in the circumferential direction. The first tooth block of the first system and the second tooth block of the first system are connected in series to form a first system. Similarly, the first tooth block of the second system and the second tooth block of the second system are connected in series to form a second system, and these two systems constitute a dual-system redundant rotary transformer.

[0109] In addition, in each tooth block, in order to make the change of the gap magnetic flux density at both ends of the tooth block moderate and reduce the electrical angle second-order component superimposed on the output signal, a structure of any one of the first to third embodiments is used. That is, it is set to any of the following structures, that is, the number of excitation windings wound on the teeth located at both ends of the tooth block is reduced by a predetermined number, the width of the teeth located at both ends of the tooth block is reduced by a predetermined amount, or the gap length of the teeth located at both ends of the tooth block is increased. In addition, the structures shown in the first to third embodiments may be combined to make the change of the gap magnetic flux density at both ends of the tooth block moderate and reduce the electrical angle second-order component superimposed on the output signal.

[0110] In addition, the first system first tooth block, the first system second tooth block, the second system first tooth block, and the second system second tooth block can be formed into one piece, or can be combined during the manufacturing process. In addition, two or more tooth blocks can also be formed into one piece.

[0111] In this way, since the stator is divided into four parts in the circumferential direction, the angle of each tooth block relative to the circumference is set to 90 degrees, and the teeth constituting a system are arranged in relative positions, the imbalance of magnetic flux when the stator or rotor is eccentric is alleviated, and the output signal becomes a sine wave with less distortion, which can improve the angle detection accuracy.

[0112] In addition, an example is shown in which the number Ns of teeth T of the stator 3 is 12 and the number Nx of salient poles of the rotor is 5, but it is not limited to this, and the number of circumferential divisions of the stator is not limited to 2 or 4. If the number of circumferential divisions of the stator is set to M, and the number of systems is set to N (N is an integer greater than 2), then M≥N, and the number of teeth is increased, and the number of teeth belonging to each tooth block after division only needs to be greater than 3. At this time, it is sufficient to set the system so that the total number of teeth of each system is the same, and the adjacent tooth blocks are different. In other words, the same total number of teeth of each system means that the sum of the division angles of the tooth blocks of each system relative to the circumference is equal, which is 360 / N degrees.

[0113] Implementation method 5.

[0114] The redundant resolver described above can be applied to an electric power steering device for a vehicle.

[0115] Next, an electric power steering device according to a fifth embodiment will be described with reference to the drawings.

[0116] Fig.21 2 is a schematic structural diagram of an electric power steering device 200 mounted on a vehicle such as an automobile. Fig.21 In the embodiment, a steering wheel (not shown) operated by a driver is connected to one end of a shaft 31, and the driver manipulates the steering wheel to transmit the torque to the shaft 31. The shaft 31 is connected to a rack shaft 33 in a housing 36. A front right wheel connecting rod 34a and a front left wheel connecting rod 34b are connected to the two ends of the rack shaft, respectively, and the right wheel (not shown) is connected to the front right wheel connecting rod 34a through a steering knuckle arm (not shown), and the left wheel (not shown) is connected to the front left wheel connecting rod 34b through a steering knuckle arm (not shown). The left and right front wheels are turned according to the steering wheel operation of the driver. In addition, a rack cover 35 is configured to prevent foreign matter from intruding into the device.

[0117] The electric power steering device 200 assists the driver in steering wheel operation. This assistance is performed by generating an auxiliary torque to assist the steering torque when the driver steers the steering wheel and generates a steering torque. For example, the auxiliary torque is generated by using the rotating motor 21 as a permanent magnet type rotating motor as a power source.

[0118] When the driver steers the steering wheel, the torque is detected by the torque sensor 32 mounted on the shaft 31. The detected torque is transmitted to the first system power supply 42 and the second system power supply 43. In addition, vehicle information such as vehicle speed is also converted into an electrical signal and transmitted to the first system power supply 42 and the second system power supply 43. The first system power supply 42 and the second system power supply 43 calculate the necessary assist torque based on the detected torque and vehicle information such as vehicle speed, and supply current to the rotating electric machine 21 through the control device 41 (inverter) of the rotating electric machine 21.

[0119] The rotating motor 21 is arranged in a direction parallel to the moving direction (arrow Z) of the rack shaft 33. The torque generated in the rotating motor is transmitted to the belt (not shown) and the ball screw in the gear box 37, generating a thrust that moves the rack shaft 33 inside the housing 36 in the direction of the arrow Z. The driver's steering force is assisted by this thrust. The front right wheel connecting rod 34a and the front left wheel connecting rod 34b are operated by the thrust of the rotating motor and the steering force of the driver, and the two wheels are steered, thereby enabling the vehicle to turn. As described above, the torque of the rotating motor is used for assistance, so that the driver can turn the vehicle with less steering force.

[0120] In the electric power steering device 200 involved in the present embodiment, the redundant rotary transformer 100 of any one of the above-mentioned embodiments 1 to 4 is applied to the rotation angle detection of the rotating motor 21. In the electric power steering device, since the cogging torque and torque ripple generated by the rotating motor are transmitted to the driver through the gears, in order to obtain a good steering feel, it is expected that the cogging torque and torque ripple are small. In addition, it is expected that the vibration and noise when the rotating motor is in operation are also small. By detecting the rotation angle of the rotating motor with high precision, the rotating motor can be smoothly controlled, and the generation of torque ripple can be suppressed compared to the case where the detection accuracy of the rotation angle is low. In addition, the same is true for vibration and noise. Therefore, the electric power steering device 200 involved in the present embodiment in which any one of the redundant rotary transformers 100 in the above-mentioned embodiments 1 to 4 is mounted on the rotating motor 21 can provide the driver with a good steering feel.

[0121] In addition, when the electric power steering device fails, the driver's steering wheel operability will be reduced. However, since the electric power steering device 200 involved in this embodiment has the redundant rotary transformer 100 of any one of the embodiments 1 to 4 with redundancy, even if one system fails, the rotation angle can be detected with high accuracy by the other system, and the auxiliary force can continue to be output.

[0122] In addition, Fig.21 , the redundant resolver 100 is mounted on the rotary electric machine 21 . However, it is also possible to mount the redundant resolver main body 1 on the rotary electric machine and to provide the control device 41 outside the rotary electric machine 21 .

[0123] The present disclosure describes various exemplary embodiments and examples, but various features, forms, and functions described in one or more embodiments are not limited to application in specific embodiments and can be applied to the embodiments alone or in various combinations.

[0124] Therefore, it is considered that numerous modifications not shown in the examples are also included in the technical scope disclosed in the present specification, for example, including the case where at least one component is modified, added or omitted, and the case where at least one component is extracted and combined with components of other embodiments.

[0125] Description of symbols

[0126] 1 Rotary transformer body

[0127] 2 rotors

[0128] 3. Stator

[0129] 4, 4a, 4b winding

[0130] 5Angle calculation unit

[0131] 6 Excitation circuit

[0132] 7. Control Circuit

[0133] 21 Rotating motor

[0134] 22 Axis

[0135] 31 axis

[0136] 32 Torque sensor

[0137] 33 rack shaft

[0138] 34a Connecting rod for front right wheel

[0139] 34b front left wheel connecting rod

[0140] 35 rack cover

[0141] 36 Shell

[0142] 37 Gear Box

[0143] 41 Control device

[0144] 42 First system power supply

[0145] 43 Second system power supply

[0146] 100 redundant resolvers

[0147] 100a Rotary Transformer of the First System

[0148] 100b Rotary transformer of the second system

[0149] 200 Electric power steering

[0150] Sa first output winding

[0151] Sb Second output winding

[0152] R Field winding

[0153] T-tooth

[0154] W Ti Tooth width

[0155] D Ti Gap length.

Claims

1. A redundant rotary transformer, comprising: A rotary transformer body, the rotary transformer body comprising a rotor having Nx salient poles, a stator opposite to the rotor and having Ns teeth arranged in a circumferential direction, and an excitation winding and two-phase output windings wound around the teeth, wherein Nx is a natural number and Ns is an integer greater than or equal to 2; an excitation circuit, the excitation circuit supplying power to the excitation winding; and An angle calculation unit calculates the rotation angle of a rotating body on which the rotor is mounted based on signals from the output windings of the two phases, wherein the redundant resolver is characterized in that: The stator is divided into M pieces in the circumferential direction to form M tooth blocks, and N redundant systems are formed based on the M tooth blocks. The sum of the division angles of each system is 360 / N degrees, where N is an integer greater than 2 and M≥N. The excitation circuit and the angle calculation unit are independently provided for each of the systems. In each of the tooth blocks, the teeth located at both ends of the tooth block have the excitation winding and the two-phase output winding, and the number of turns of the excitation winding wound on the teeth located at both ends of the tooth block is smaller than the number of turns of the excitation winding wound on the teeth not located at both ends.

2. The redundant rotary transformer according to claim 1, characterized in that: When the ratio of the number of turns of the field winding wound around the teeth located at both ends of the tooth block to the number of turns of the field winding wound around the teeth not located at both ends is defined as A, 2 / 7<A<1.

3. The redundant rotary transformer according to claim 2, characterized in that: When A is a ratio of the number of turns of the field winding wound around the teeth located at both ends of the tooth block to the number of turns of the field winding wound around the teeth not located at both ends, A=2 / 3.

4. The redundant rotary transformer according to claim 1, characterized in that: In each of the tooth blocks, the width of the teeth located at both ends of the tooth block is made smaller than the width of the teeth not located at both ends.

5. The redundant rotary transformer according to claim 1, characterized in that: In each of the tooth blocks, a gap length between the teeth located at both ends of the tooth block and the rotor is made greater than a gap length between the teeth not located at both ends and the rotor.

6. A redundant rotary transformer, comprising: A rotary transformer body, the rotary transformer body comprising a rotor having Nx salient poles, a stator opposite to the rotor and having Ns teeth arranged in a circumferential direction, and an excitation winding and two-phase output windings wound around the teeth, wherein Nx is a natural number and Ns is an integer greater than or equal to 2; an excitation circuit, the excitation circuit supplying power to the excitation winding; and An angle calculation unit calculates the rotation angle of a rotating body on which the rotor is mounted based on signals from the output windings of the two phases, wherein the redundant resolver is characterized in that: The stator is divided into M pieces in the circumferential direction to form M tooth blocks, and N redundant systems are formed based on the M tooth blocks. The sum of the division angles of each system is 360 / N degrees, where N is an integer greater than 2 and M≥N. The excitation circuit and the angle calculation unit are independently provided for each of the systems. In each of the tooth blocks, the teeth located at both ends of the tooth block have the excitation winding and the two-phase output windings, and the width of the teeth located at both ends of the tooth block is smaller than the width of the teeth not located at both ends.

7. The redundant rotary transformer according to claim 6, characterized in that: When a ratio of the width of the teeth located at both ends of the tooth block to the width of the teeth not located at both ends is defined as B, 7 / 9<B<1.

8. The redundant rotary transformer according to claim 7, characterized in that: When the ratio of the width of the teeth located at both ends of the tooth block to the width of the teeth not located at both ends is defined as B, B=5 / 6.

9. The redundant rotary transformer according to claim 6, characterized in that: In each of the tooth blocks, a gap length between the teeth located at both ends of the tooth block and the rotor is made greater than a gap length between the teeth not located at both ends and the rotor.

10. A redundant rotary transformer, comprising: A rotary transformer body, the rotary transformer body comprising a rotor having Nx salient poles, a stator opposite to the rotor and having Ns teeth arranged in a circumferential direction, and an excitation winding and two-phase output windings wound around the teeth, wherein Nx is a natural number and Ns is an integer greater than or equal to 2; an excitation circuit, the excitation circuit supplying power to the excitation winding; and An angle calculation unit calculates the rotation angle of a rotating body on which the rotor is mounted based on signals from the output windings of the two phases, wherein the redundant resolver is characterized in that: The stator is divided into M pieces in the circumferential direction to form M tooth blocks, and N redundant systems are formed based on the M tooth blocks. The sum of the division angles of each system is 360 / N degrees, where N is an integer greater than 2 and M≥N. The excitation circuit and the angle calculation unit are independently provided for each of the systems. In each of the tooth blocks, the teeth located at both ends of the tooth block have the excitation winding and the two-phase output winding, and the gap length between the teeth located at both ends of the tooth block and the rotor is greater than the gap length between the teeth not located at both ends and the rotor.

11. The redundant rotary transformer according to any one of claims 1 to 10, characterized in that: The excitation circuit supplies power to the excitation winding at an excitation frequency that is different for each of the systems.

12. The redundant rotary transformer according to any one of claims 1 to 10, characterized in that: The angle calculation unit provided for each system removes excitation signal components of other systems.

13. The redundant rotary transformer according to any one of claims 1 to 10, characterized in that: M=2, N=2, and the stator is divided into two and set as two systems.

14. The redundant rotary transformer according to any one of claims 1 to 10, characterized in that: M=4, N=2, the stator is divided into four in the circumferential direction and provided as two systems, and the tooth blocks of the same systems are arranged to face each other.

15. An electric power steering device, The electric power steering device includes a rotating electric machine for generating an assist torque for assisting a steering torque of a vehicle, and is characterized by mounting a redundant resolver according to any one of claims 1 to 14.

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