Redundant resolver and electric power steering device equipped with the same

Abstract

The redundant rotary transformer of the present invention includes: a rotary transformer body (4) having a rotor (42) having Nx (Nx is a natural number) salient poles, a stator (41) having Ns (Ns is an integer of 3 or more) teeth (411) arranged circumferentially opposite to the rotor (42), and an excitation winding (R) and a two-phase output winding (Sa, Sb) wound around the teeth; and an excitation circuit (511, 512) applying a voltage to the excitation winding (R), wherein the excitation winding wound around Nsm (Nsm is an integer of 2 or more) of the Ns teeth and the two-phase output winding are designated as the main system (101), and the excitation winding wound around Ns-Nsm teeth and the two-phase output winding are designated as the sub-system (102), wherein the number of teeth Nsm corresponding to the main system (101) is greater than the number of teeth Ns-Nsm corresponding to the sub-system (102).

Description

Technical Field

[0001] This application relates to redundant rotary transformers and electric power steering systems equipped with redundant rotary transformers. Background Technology

[0002] Among rotary transformers that utilize the change in magnetic permeability in the gap between the rotor and stator, there are known multi-system rotary transformers with two sets of excitation windings connected to different excitation circuits, also known as redundant rotary transformers.

[0003] For example, Patent Document 1 discloses a method for redundancy in a redundant rotary transformer with two excitation windings by dividing a rotary transformer stator circumferentially to reduce axial dimensions and designating it as a first system and a second system.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 4147930

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

[0008] The technical problem that the invention aims to solve

[0009] However, in Patent Document 1, the number of teeth constituting the first system and the second system is half the total number of teeth of the rotary transformer stator, which leads to the following problem: the angle detection accuracy deteriorates compared to a single-system rotary transformer.

[0010] To suppress the deterioration of angle detection accuracy in such redundant rotary transformers, it is disclosed to stack two rotary transformers in two stages along the axial direction, 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, see Patent Document 2).

[0011] However, in Patent Document 2, since two rotary transformers are stacked in two stages via a shaft, the following problem exists: the axial dimension is increased by 2 times compared to a single-system rotary transformer.

[0012] This application discloses a technology for solving the above-mentioned problems, the purpose of which is to provide a redundant rotary transformer with high angle detection accuracy of its main system without increasing its size.

[0013] Technical means for solving technical problems

[0014] The redundant rotary transformers disclosed in this application include:

[0015] The rotary transformer body includes a rotor with Nx (Nx is a natural number) salient poles, a stator opposite the rotor with Ns (Ns is an integer greater than or equal to 3) teeth arranged circumferentially, and an excitation winding wound around the teeth and a two-phase output winding; and

[0016] The excitation circuit applies voltage to the excitation winding.

[0017] The redundant rotary transformer is characterized by comprising: a primary system consisting of an excitation winding wound on Nsm teeth (where Nsm is an integer greater than or equal to 2) and a two-phase output winding; and a secondary system consisting of an excitation winding wound on Ns-Nsm teeth and a two-phase output winding.

[0018] The main system arithmetic unit receives the voltage of the two-phase output winding in the main system as input and calculates the angle in the main system; and

[0019] The secondary system arithmetic unit receives the voltages of the two-phase output windings in the secondary system as input and calculates the angles in the secondary system.

[0020] The number of teeth Nsm corresponding to the main system is more than the number of teeth Ns-Nsm corresponding to the secondary system.

[0021] Invention Effects

[0022] According to the redundant rotary transformer disclosed in this application, the angle detection accuracy is improved without increasing the size by making the number of teeth of the stator constituting the main system more than half of the total number of teeth. Attached Figure Description

[0023] Figure 1 This is a diagram showing an example of installing the redundant rotary transformer according to Embodiment 1 on a rotary electric machine.

[0024] Figure 2 This is a diagram illustrating an example of the hardware structure of a control circuit.

[0025] Figure 3 This is a diagram showing the structure of the redundant rotary transformer according to Embodiment 1.

[0026] Figure 4 This is a cross-sectional view of the main body of the redundant rotary transformer according to Embodiment 1.

[0027] Figure 5 This is a cross-sectional view of the stator of the redundant rotary transformer according to Embodiment 1.

[0028] Figure 6 This is a diagram showing the number of turns of the excitation winding of the redundant rotary transformer according to Embodiment 1.

[0029] Figure 7 This is a diagram showing the number of turns in the output winding of the redundant rotary transformer according to Embodiment 1.

[0030] Figure 8 This is a graph showing the angle detection accuracy of the redundant rotary transformer according to Embodiment 1 and the comparative example.

[0031] Figure 9 This is a graph showing the relationship between the number of teeth and the angle detection accuracy of the main system of the redundant rotary transformer involved in Embodiment 1.

[0032] Figure 10 This is a diagram showing the structure of the redundant rotary transformer according to Embodiment 2.

[0033] Figure 11 This is a diagram showing the excitation signals of the main system and the secondary system of the redundant rotary transformer involved in Embodiment 2.

[0034] Figure 12 This is a diagram showing the output signal waveform of the main system of the redundant rotary transformer according to Embodiment 2.

[0035] Figure 13 This is a diagram showing the output signal waveform of the secondary system of the redundant rotary transformer according to Embodiment 2.

[0036] Figure 14 This is a schematic structural diagram of the electric power steering device involved in Embodiment 3. Detailed Implementation

[0037] Hereinafter, this embodiment will be described with reference to the accompanying drawings. Furthermore, in each drawing, the same reference numerals denote the same or equivalent parts.

[0038] Implementation method 1.

[0039] <Excitation Cycle>

[0040] The redundant rotary transformer described in Embodiment 1 will be explained below.

[0041] Figure 1 This diagram shows an example of mounting the redundant rotary transformer 1 according to Embodiment 1 to a rotary electric machine. Furthermore, although an example of mounting the shaft 3 to the rotary electric machine 2 is shown, the mounting object is not limited to rotary electric machines if it is a rotating shaft of a rotating part (rotating body) of various other devices.

[0042] Figure 1In this embodiment, a redundant rotary transformer 1 is mounted on shaft 3, which serves as the rotating shaft of the rotary motor 2. The redundant rotary transformer 1 includes a rotary transformer body 4 serving as a sensor and a control circuit 5 for controlling it. The rotary transformer body 4 includes a pair of stators 41 and a rotor 42, with windings 43 wound on the stators 41. The rotor 42 is connected to the rotating part of the rotary motor 2 via shaft 3. The control circuit 5 includes an excitation circuit 51 that applies an AC voltage to the excitation winding of the winding 43 (described later) for excitation; and an angle calculation unit 52 that calculates the rotation angle based on the signal waveform of the output winding of the winding 43 (described later). Figure 3 As will be described later, the excitation circuit 51 and the angle calculation unit 52 in the main system and the sub-system include excitation circuits 511 and 512 and angle calculation units 521 and 522, respectively.

[0043] exist Figure 2 The diagram shows an example of the hardware of the microcomputer with control circuit 5. It consists of a processor 500 and a storage device 510. Although not shown, the storage device 510 includes a volatile storage device such as random access memory and a non-volatile auxiliary storage device such as flash memory. Alternatively, an auxiliary storage device such as a hard disk can be used instead of flash memory. The processor 500 performs angle calculations, such as those in the angle calculation unit 52, by executing a program input from the storage device 510. In this case, the program is input from the auxiliary storage device to the processor 500 via the volatile storage device. Furthermore, the processor 500 can output data such as calculation results to the volatile storage device of the storage device 510, or save data to the auxiliary storage device via the volatile storage device.

[0044] In addition, the hardware in the control circuit 5 may not be a microcomputer, but may be an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), a simple logic circuit, or a relay, etc.

[0045] Figure 3This is a diagram illustrating the structure of the redundant rotary transformer 1 according to Embodiment 1. In the diagram, the redundant rotary transformer 1 includes a rotary transformer for the main system 101 and a rotary transformer for the sub-system 102. Both the rotary transformers of the main system 101 and the sub-system 102 have a first output winding Sa, a second output winding Sb, and an excitation winding R, forming a winding 43 structure. The first output winding Sa and the second output winding Sb are respectively connected to angle calculation units 521 and 522, and the excitation winding R is respectively connected to excitation circuits 511 and 512. The angle calculation unit 521 of the main system 101 and the angle calculation unit 522 of the sub-system 102 are connected via an angle calculation unit communicator 6. The main system detects an angle θm, and the sub-system detects an angle θs, which are input to the angle calculation unit communicator 6. When both the main system 101 and the sub-system 102 are functioning normally, the main system detects an angle θm, which is output to, for example, a control device 13 (see reference 13). Figure 14 ).

[0046] The main system's detected angle θm and the secondary system's detected angle θs are input to the angle calculation unit communicator 6. In the event of a failure in the main system 101, the secondary system's detected angle θs is output to the control device 13. Furthermore, in the event of a failure in the secondary system 102, the main system's detected angle θm is output to the control device 13. Similarly, the excitation circuit 511 of the main system 101 and the excitation circuit 512 of the secondary system 102 are connected via an excitation circuit communicator 7. In the excitation circuit communicator 7, the phases of the main system excitation signal and the secondary system excitation signal output from the excitation circuit 511 of the main system 101 and the excitation circuit 512 of the secondary system 102 are kept synchronized to avoid magnetic interference between the main system 101 and the secondary system 102. Therefore, angle calculation units 521 and 522 and excitation circuits 511 and 512 are provided in each system to ensure redundancy.

[0047] Figure 4 yes Figure 1 A cross-sectional view of the main body 4 of the rotary transformer in the X-X line. Figure 4 In this embodiment, the winding 43 is wound around each tooth 411 of the stator 41, which has a yoke 412 and teeth 411. The rotor 42, which has salient poles, is mounted on the shaft 3. In this embodiment 1, the number of teeth 411 Ns of the stator of the redundant rotary transformer 1 is 12, and the number of salient poles Nx of the rotor 42 is set to 5. The number of salient poles Nx is also referred to as the shaft multiple angle.

[0048] Figure 5 From Figure 4 The diagram with rotor 42 and shaft 3 removed is equivalent to a cross-sectional view of stator 41, showing a portion of the structure of the rotary transformer of main system 101 and auxiliary system 102. As described above, the number of teeth Ns of stator 411 of redundant rotary transformer 1 is 12. Figure 5If each tooth 411 is designated as tooth T1 to tooth T12 in the clockwise direction, then as shown by the YY line in the figure, it is divided circumferentially into two parts: the main system teeth consisting of teeth T1 to tooth T7, and the secondary system teeth consisting of teeth T8 to tooth T12. That is, there are 7 main system teeth and 5 secondary system teeth, with the main system teeth being more numerous. These main system teeth constitute the rotary transformer of the main system 101, and the secondary system teeth constitute the rotary transformer of the secondary system 102. Together, they form a redundant rotary transformer 1 in a dual-system configuration.

[0049] Next, the winding 43 wound around each tooth T1 to T12 will be described.

[0050] A winding group consisting of a one-phase excitation winding R and two-phase output windings, namely the first output winding Sa and the second output winding Sb, is wound on teeth T1 to T12. That is, the excitation windings R1 to R7 of the main system 101, the first output windings Sa1 to Sa7 of the main system 101, and the second output windings Sb1 to Sb7 of the main system 101 are wound on teeth T1 to T7 of the main system. Similarly, the excitation windings R8 to R12 of the secondary system 102, the first output windings Sa8 to Sa12 of the secondary system 102, and the second output windings Sb8 to Sb12 of the secondary system 102 are wound on teeth T8 to T12 of the secondary system. Figure 5 The diagram only shows the first output winding Sa1, the second output winding Sb1, and the excitation winding R1 of tooth T1, as well as the first output winding Sa11, the second output winding Sb11, and the excitation winding R11 of tooth T11.

[0051] The excitation windings R1 to R7 of the main system 101 and the excitation windings R8 to R12 of the auxiliary system 102 are respectively connected to the excitation circuit 511 of the main system 101 and the excitation circuit 512 of the auxiliary system 102 via excitation terminals (not shown) provided in the extension (not shown) of the rotary transformer.

[0052] The first output windings Sa1 to Sa7 and the second output windings Sb1 to Sb7 of the main system 101 are connected to the angle calculation unit 521 of the main system 101 via output terminals (not shown) provided in the extension of the rotary transformer. The first output windings Sa8 to Sa12 and the second output windings Sb8 to Sb12 of the auxiliary system 102 are connected to the angle calculation unit 522 of the auxiliary system 102 via output terminals (not shown) provided in the extension of the rotary transformer. The angle calculation unit 521 of the main system 101 and the angle calculation unit 522 of the auxiliary system 102 use the output signals from the two-phase output windings of the first output winding Sa and the second output winding Sb to calculate the main system detection angle θm and the auxiliary system detection angle θs of the rotor and output them (see reference). Figure 3 ).

[0053] Figure 5 In the stator core, focusing on tooth T1, the excitation winding R1 is wound first, followed by the first output winding Sa1 and the second output winding Sb1 in sequence. That is, the configuration involves first winding the excitation winding R1, and then winding the two-phase output windings on top of it. The winding order of the first output winding Sa1 and the second output winding Sb1 is not limited to this; either one can be wound first. Furthermore, sometimes a tooth is provided that does not have either the first output winding Sa1 or the second output winding Sb1 wound on it. The stator core including tooth T1 and the windings R1, Sa1, and Sb1 are insulated by insulating paper, coatings, resin, etc. (not shown). While tooth T1 has been described, the other teeth T2 to T12 are also wound with the excitation windings R2 to R12, the first output windings Sa2 to Sa12, and the second output windings Sb2 to Sb12 in the same manner.

[0054] The excitation windings R1 to R7, the first output windings Sa1 to Sa7, and the second output windings Sb1 to Sb7 are connected in series. Similarly, the excitation windings R8 to R12, the first output windings Sa8 to Sa12, and the second output windings Sb8 to Sb12 are also connected in series.

[0055] In addition, here, the windings are connected in series in the order of teeth T1 to T7 and teeth T8 to T12. However, even if the teeth at the beginning of winding are any teeth Ti in each system and are connected in series from adjacent teeth, the same effect can be obtained.

[0056] In addition, the excitation winding R and the first output winding Sa and the second output winding Sb, which are two-phase output windings, can be wound in a circumferential direction, but this is not a limitation. The same effect can be achieved by arranging them in a radial direction or by changing the winding order for each tooth.

[0057] Next, the number of turns of the excitation windings R1 to R7 of the main system 101 and the excitation windings R8 to R12 of the redundant rotary transformer according to Embodiment 1 will be explained. Figure 6This diagram illustrates the winding distribution in the redundant rotary transformer according to Embodiment 1. In the diagram, the number of turns of the excitation winding is normalized according to amplitude, and the number of turns of the excitation winding R wound on the main system teeth T1-T7 and the auxiliary system teeth T8-T12 is shown continuously. A winding direction (+) and a winding direction (-) are defined in the excitation winding of the rotary transformer. In the redundant rotary transformer 1 of Embodiment 1, the winding directions (+) and (-) of the excitation winding R are alternately arranged. The winding directions (+) and (-) represent the different winding polarities of the windings. If the winding direction (+) is used to represent the direction of a coil's winding, then a coil wound in the opposite direction is represented by the winding direction (-). The absolute value of the number of turns in the winding direction (+) is the same as the absolute value of the number of turns in the winding direction (-). Therefore, the spatial order Ne of the excitation winding R is 6. That is, if the number of turns in the winding direction (+) is set to +X turns, then the number of turns in the winding direction (-) is -X turns. Furthermore, here, the winding direction (+) and winding direction (-) are alternately wound, and the spatial order of the excitation winding R is 6. However, it is not limited to this; other winding configurations are also possible, such as a winding configuration with a spatial order of 3 for the excitation windings arranged in two teeth in the winding direction (+) and winding direction (-).

[0058] Figure 7 This diagram illustrates the distribution of turns in the first output windings Sa1-Sa7 and the second output windings Sb1-Sb7 of the main system 101 and the first output windings Sa8-Sa12 and the second output windings Sb8-Sb12 of the sub-system 102 of the redundant rotary transformer 1 according to this embodiment. In the diagram, the number of turns in the output windings is normalized according to the amplitude, and the number of turns in the output windings wound on the main system teeth T1-T7 and the sub-system teeth T8-T12 are shown consecutively. The number of turns N in the first output winding and the second output winding wound on the i-th tooth is also shown. Sai and N Sbi The phase difference of the windings is 90°, which can be expressed by the following equation (1).

[0059] [Mathematical Expression 1]

[0060]

[0061]

[0062] |α-β|=90°

[0063] Equation (1)

[0064] Here, N1 represents the amplitude of the number of turns in the output winding, θ teethThis indicates the circumferential position of the teeth. The spatial order Ne of the excitation winding R is 6, and the axis multiple angle Nx is 5; therefore, the spatial order of the output winding is 1. The output winding is distributed in a sinusoidal pattern along the circumference of the teeth. When the number of turns is a decimal, it is rounded to the nearest integer. Here, in the same diagram, the number of turns of the output winding is normalized to its amplitude, N1.

[0065] Figure 8 This graph compares the angle detection accuracy of the redundant rotary transformer 1 according to Embodiment 1 with that of a comparative example, namely a redundant rotary transformer with 6 teeth in the main system. The vertical axis normalizes the electrical angular fifth-order component of the angle error using the values ​​of the comparative example. By setting the number of teeth in the main system to 7, the number of teeth in the output signal is increased, thus improving the angle detection accuracy of the main system 101.

[0066] The redundant rotary transformer 1 of this embodiment 1 communicates between the angle calculation unit 521 of the main system 101 and the angle calculation unit 522 of the sub-system 102, inputting the main system detected angle θm to the control device 13 to control the rotary motor 2. If the angle calculation unit 521 or the angle calculation unit communicator 6 detects a fault in the main system 101, it inputs the sub-system detected angle θs to the control device 13. If the angle calculation unit 522 or the angle calculation unit communicator 6 detects a fault in the sub-system 102, it inputs the main system detected angle θm to the control device 13. Therefore, the redundant rotary transformer of this embodiment 1, although having the same dimensions as a single-system rotary transformer, achieves redundancy, and compared to a redundant rotary transformer that redundant by dividing the stator in half, it improves the angle detection accuracy under normal conditions.

[0067] Figure 9 The angle detection accuracy is shown as the number of main system teeth varies from 3 to 11. Here, the vertical axis is normalized to the fifth-order electrical angular component of the angle error using comparative examples. By setting the number of main system teeth to 7 or more, i.e., more than half the total number of teeth, the angle detection accuracy is improved compared to when the number of main system teeth and auxiliary system teeth are the same.

[0068] Here, the shaft multiple angle Nx of the redundant rotary transformer involved in this embodiment 1 is set to 5, and the number of teeth Ns is set to 12. However, it is not limited to this. As long as Nx is a natural number and Ns is an integer greater than 3, the same effect can be obtained even with other numbers.

[0069] Implementation method 2.

[0070] <Excitation Frequency Separation>

[0071] Figure 10This diagram illustrates the structure of the redundant rotary transformer 1a according to Embodiment 2. In the diagram, the redundant rotary transformer 1a includes a rotary transformer for the main system 101a and a rotary transformer for the sub-system 102a. The excitation circuit 511a of the main system 101a and the excitation circuit 512a of the sub-system 102a are not connected via an excitation circuit communicator, but are independent of each other. By adopting this structure, common faults caused by the excitation circuit communicator can be prevented, thus further improving the safety of the redundant rotary transformer.

[0072] As described above, in the redundant rotary transformer 1a of this embodiment 2, the excitation circuit 511a that provides excitation signals to the excitation windings R1 to R7 of the main system 101a and the excitation circuit 512a that provides excitation signals to the excitation windings R8 to R12 of the auxiliary system 102a are independent of each other, thus ensuring redundancy.

[0073] However, due to their independence, it is difficult to synchronize the excitation signals of the main system 101a and the secondary system 102a. Because of manufacturing variations in components such as the microcomputers constituting the excitation circuits 511a and 512a, even if the frequencies of the excitation signals of the main system 101a and the secondary system 102a are designed to be the same, they cannot be completely synchronized, resulting in slight differences. Therefore, the difference between the excitation signals of the main system 101a and the secondary system 102a is not constant but varies over time, affecting other systems and contributing to the deterioration of angle detection accuracy.

[0074] Therefore, excitation signals of different frequencies are provided to the corresponding excitation windings R from each excitation circuit 511a and 512a. Figure 11 The excitation signals of the main system 101a and the secondary system 102a of the redundant rotary transformer 1 according to Embodiment 2 are shown. The frequency f1 of the excitation signal of the main system 101a is 10kHz, and the frequency f2 of the excitation signal of the secondary system 102a is 20kHz. In addition, the voltage of the excitation signal is normalized by amplitude in the vertical axis.

[0075] Furthermore, the angle calculation unit 521a of the main system 101a and the angle calculation unit 522a of the sub-system 102a each have the function of removing frequency components from other systems. That is, the component generated by the excitation signal of the sub-system 102a is removed from the first output signal and the second output signal of the main system 101a, and only the component generated by the excitation signal of the main system 101a is extracted. Similarly, the component generated by the excitation signal of the main system 101a is removed from the first output signal and the second output signal of the sub-system 102a, and only the component generated by the excitation signal of the sub-system 102a is extracted. The method for removing frequency components from other systems will be described below.

[0076] Figure 12 This diagram illustrates the waveform of the output signal of the main system 101a. From top to bottom, it shows the waveforms of the output signal of the main system 101a, the excitation signal of the main system 101a, and the excitation signal of the secondary system 102a. The output signal of the main system 101a was originally a waveform with frequency f1 corresponding to the excitation signal of the main system 101a, but it became a waveform after adding the frequency f2 component of the excitation signal of the secondary system 102a.

[0077] like Figure 12 As shown, +A and -A of the excitation signal of the main system 101a correspond to the positive and negative peak values ​​of the signal, respectively. However, since the excitation signal component +Bn of the secondary system 102a is added, the output signal of the main system 101a becomes a waveform distorted from a sine wave. Therefore, if the output signal of the main system 101a is sampled with a period of 1 / f1 and an arctangent operation is performed directly, an error is generated due to the component of the excitation signal frequency f2 of the secondary system.

[0078] Therefore, the output signal of the main system 101a is sampled at 2 / f1 and set as {(A+Bn)-(-A+Bn)} / 2. This allows us to extract only the component A of the excitation signal frequency f1 of the main system 101a and remove the component Bn of the excitation signal frequency f2 of the sub-system 102a, thereby improving the accuracy of the rotation angle detection.

[0079] Figure 13 This diagram illustrates the waveform of the output signal of the secondary system 102a. Starting from top to bottom, it shows the waveforms of the output signal of the secondary system 102a, the excitation signal of the secondary system 102a, and the excitation signal of the primary system 101a. The original output signal of the secondary system 102a was a waveform with frequency f2 corresponding to the excitation signal of the secondary system 102a. However, it becomes a waveform after adding a component of frequency f1 of the excitation signal of the primary system 101a. As shown in the diagram, +B, -B, +B, and -B of the excitation signal of the secondary system 102a correspond to the positive and negative peak values ​​of the signal, respectively. However, due to the addition of the excitation signal components +An1, +An2, -An1, and -An2 of the primary system 101a, the output signal of the secondary system 102a becomes a waveform distorted from a sine wave. Therefore, if the output signal of the secondary system 102a is sampled with a period of 1 / f2 and an arctangent operation is directly performed, an error is generated due to the component of frequency f1 of the excitation signal of the primary system 101a.

[0080] Therefore, the output signal of the secondary system 102a is sampled at 2 / f2 and set as {(B+An1)+(B-An1)-(-B+An2)-(-B-An2)} / 4. This allows us to extract only the component B of the excitation signal frequency f2 of the secondary system 102a and remove the component An of the excitation signal frequency f1 of the main system 101a, thus improving the accuracy of the rotation angle detection.

[0081] In the redundant rotary transformer of this embodiment 2, a main system 101a and a secondary system 102a are arranged on a circular stator. Furthermore, different frequency excitation signals are provided to each system, and the influence of excitation signals from other systems is removed in the angle calculation units 521a and 522a. Thus, the main system 101a and the secondary system 102a are in an independent state. That is, if we consider the main system 101a, it becomes a physical state similar to the following: the excitation signal is not applied to the excitation winding R of the secondary system 102a wound around the teeth of the secondary system 102a, and the secondary system 102a experiences faults such as open circuits. Conversely, if we consider the secondary system 102a, it becomes a physical state similar to the following: the main system 101a experiences faults such as open circuits. This leads to the advantage that by providing excitation signals of different frequencies from independent excitation circuits 511a and 512a, signals that do not affect the signals of other systems can be obtained.

[0082] By adopting this structure, the following effects can be achieved: Safety is improved because no common faults caused by the excitation circuit communicator are generated. Furthermore, magnetic interference between the main and secondary systems is avoided, thus improving angle detection accuracy.

[0083] Implementation method 3.

[0084] <Integration of electric power steering>

[0085] The redundant rotary transformer 1 described above can be applied to electric power steering systems for vehicles.

[0086] The following is for reference Figure 14 To illustrate the electric power steering device involved in Embodiment 3.

[0087] Figure 14 This is a schematic diagram of an electric power steering system used in automobiles and other vehicles. Figure 14In this design, the driver's steering wheel (not shown) is connected to one end of shaft 8. The driver operates the steering wheel, transmitting its torque to shaft 8. Shaft 8 is connected to a rack shaft (not shown) inside housing 9. At both ends of the rack shaft are connecting links 10a for the right front wheel and 10b for the left front wheel. The right wheel (not shown) is connected to the right front wheel connecting link 10a via a steering knuckle arm (not shown), and the left wheel (not shown) is connected to the left front wheel connecting link 10b via a steering knuckle arm (not shown). The driver's steering wheel operation steers the left and right front wheels. Furthermore, the rack sleeve 14 is configured to prevent foreign objects from entering the device.

[0088] Electric power steering assists the driver in steering wheel operation. This assistance is achieved by generating an auxiliary torque that assists the steering torque when the driver turns the steering wheel and generates steering torque. For example... Figure 1 As explained, the auxiliary torque is generated by using a rotary motor 2, which is a permanent magnet type rotary motor, as a power source. When the driver turns the steering wheel, the torque is detected by a torque sensor 11 mounted on shaft 8. The detected torque is transmitted to the main system power supply 20 and the auxiliary system power supply 21. In addition, vehicle information such as vehicle speed is also converted into electrical signals and transmitted to the main system power supply 20 and the auxiliary system power supply 21. The main system power supply 20 and the auxiliary system power supply 21 calculate the required auxiliary torque based on the detected torque and vehicle information such as vehicle speed, and supply current to the rotary motor 2 through the rotary motor control device 13 (inverter, etc.). Power is supplied from the power supply 22 to the control device 13 via a power connector. Furthermore, as... Figure 1 As explained, the redundant rotary transformer 1 is mounted on the shaft 3 of the rotary motor 2. The redundant rotary transformer 1 detects the rotation angle of the rotor of the rotary motor 2 and outputs a corresponding rotation angle signal. Furthermore, similar to the control circuit 5, the control device 13 can also be connected via... Figure 2 The hardware structure shown is used to construct it.

[0089] The rotary motor 2 is configured parallel to the direction of movement of the rack shaft (arrow Z). The torque generated in the rotary motor 2 is transmitted to the belt and ball screw inside the gearbox 12, generating a thrust that moves the rack located inside the housing 9 axially in the direction of arrow Z. This thrust is used to assist the driver's steering force. The right front wheel linkage 10a and the left front wheel linkage 10b are actuated by the thrust of the rotary motor 2 and the driver's steering force, thereby enabling the two wheels to turn and the vehicle to turn.

[0090] Therefore, by utilizing the torque of the rotary motor 2 for assistance, the driver can turn the vehicle with less steering force. In the electric power steering device according to this embodiment, the redundant rotary transformer 1 of Embodiment 1 or 2 described above is used for detecting the rotation angle of the rotary motor 2. In the electric power steering device, since the cogging torque and torque pulsation generated by the rotary motor 2 are transmitted to the driver via gears, it is desirable to have low cogging torque and low torque pulsation in order to obtain good steering feel. In addition, it is desirable to have low vibration and noise when the rotary motor 2 is operating.

[0091] Therefore, by accurately detecting the rotation angle of the rotary motor 2, the rotary motor can be smoothly controlled, and torque pulsation can be suppressed compared to cases with low accuracy in detecting the rotation angle. The same applies to vibration and noise. Therefore, the electric power steering system that mounts the redundant rotary transformer 1 of Embodiment 1 or 2 described above to the rotary motor 2 can provide the driver with a good steering feel.

[0092] Furthermore, in implementation 1 or 2, the redundant rotary transformer 1 can still accurately detect the rotation angle through the other system even if one system fails, and can continuously output auxiliary force. Additionally, Figure 1 The diagram shows the redundant rotary transformer 1 installed on the rotary motor, but of course, the main body of the redundant rotary transformer 1 can also be installed inside the rotary motor, and the control circuit 5 can be placed outside the rotary motor 2.

[0093] This disclosure describes various exemplary embodiments and examples, but the various features, forms and functions described in one or more embodiments are not limited to the application of a specific embodiment, and can be applied to the embodiment alone or in various combinations.

[0094] Therefore, it can be assumed that numerous variations not illustrated are also included within the scope of the technology disclosed in this application. For example, this includes cases where at least one constituent element is modified, added to, or omitted, and cases where at least one constituent element is extracted and combined with constituent elements of other embodiments.

[0095] Label Explanation

[0096] 1. Redundant rotary transformer

[0097] 2 Rotary motor

[0098] 3-axis

[0099] 4. Rotary Transformer Body

[0100] 5. Control Circuit

[0101] 6 Angle Calculation Unit Communicator

[0102] 7. Excitation circuit communicator

[0103] 101, 101a Main System

[0104] Subsystems 102 and 102a

[0105] Excitation circuits for 511, 511a, 512, and 512a

[0106] 521, 521a, 522, 522a Angle calculation unit.

Claims

1. A redundant rotary transformer, comprising: The main body of the rotary transformer includes a rotor having Nx salient poles, a stator having Ns teeth arranged circumferentially opposite the rotor, and an excitation winding and a two-phase output winding wound around the teeth, where Nx is a natural number and Ns is an integer greater than or equal to 3. as well as An excitation circuit applies a voltage to the excitation winding. The redundant rotary transformer is characterized by comprising: a primary system consisting of an excitation winding wound on Nsm teeth and a two-phase output winding wound on Ns-Nsm teeth; and a secondary system consisting of an excitation winding wound on Ns-Nsm teeth and a two-phase output winding, where Nsm is an integer greater than or equal to 2. The main system angle calculation unit is input with the voltage of the two-phase output winding in the main system and calculates the angle in the main system. as well as The subsystem angle calculation unit receives the voltages of the two-phase output windings in the subsystem as input and calculates the angles in the subsystem. The number of teeth Nsm corresponding to the main system is more than the number of teeth Ns-Nsm corresponding to the subsystem, and more than half of the total number of teeth Ns. The main system angle calculation unit and the auxiliary system angle calculation unit are connected. When both the main system and the auxiliary system are functioning normally, the main system detection angle calculated by the main system angle calculation unit is output to the control device of the rotating motor. If the main system fails, the auxiliary system detection angle calculated by the auxiliary system angle calculation unit is output to the control device of the rotating motor. If the auxiliary system fails, the main system detection angle is output to the control device of the rotating motor. The excitation circuit consists of a main system excitation circuit and a secondary system excitation circuit. The main system excitation circuit applies voltage to the excitation winding corresponding to the main system, and the secondary system excitation circuit applies voltage to the excitation winding corresponding to the secondary system. The main system excitation frequency of the AC voltage supplied to the excitation winding by the main system excitation circuit is different from the secondary system excitation frequency of the AC voltage supplied to the excitation winding by the secondary system excitation circuit. The main system angle calculation unit extracts only the frequency component of the main system's excitation signal and removes the frequency component of the secondary system's excitation signal, based on the value obtained by sampling the main system's output signal at twice the period of the main system's excitation signal. The subsystem angle calculation unit extracts only the frequency component of the subsystem's excitation signal and removes the frequency component of the main system's excitation signal, based on the value obtained by sampling the subsystem's output signal at twice the period of the subsystem's excitation signal.

2. The redundant rotary transformer as described in claim 1, characterized in that, The main system angle calculation unit and the sub-system angle calculation unit are connected to the angle calculation unit communicator.

3. An electric power steering device, characterized in that, It is equipped with the redundant rotary transformer as described in claim 1 or 2.

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