A position sensorless control method for a single-winding bearingless switched reluctance motor

Abstract

The present invention discloses a position sensorless control method for a single-winding bearingless switched reluctance motor, comprising the following steps: when the motor is stationary, injecting a preset first pulse into the motor's three-phase windings, obtaining the pulse sampling currents corresponding to the three phases, and calculating the inductance differences of the three phases at different sampling periods; based on the inductance differences, obtaining the position interval and the excitation phase within the interval, and starting the motor; when the motor is started, injecting a preset second pulse only into the non-excitation phase, obtaining the pulse sampling current corresponding to the non-excitation phase, calculating the inductance differences of the non-excitation phase at different sampling periods, and performing a commutation operation. This method overcomes the defects of the prior art in the motor's stationary starting and running commutation, such as complex judgment logic and excessively long commutation time, by determining the position interval and the excitation phase within the interval based on the inductance difference, and then performing a commutation operation. The overall logic is simple and practical, effectively improving the dynamic performance of the motor.

Description

Technical Field

[0001] The invention relates to a position sensorless control method for a single-winding bearingless switched reluctance motor, belonging to the technical field of motor control applications. Background Art

[0002] The Bearingless Switched Reluctance Motor with Wider Rotor Teeth (BSRMWR) achieves a natural decoupling of torque and suspension force, simplifying motor control. BSRMWRs offer a simple, robust structure, low cost, reliable operation, no lubrication, and long life. They have significant applications in high-speed and ultra-high-speed aviation starter generators, flywheel energy storage, and other fields.

[0003] The high-performance operation and precise control of wide-rotor-tooth bearingless switched reluctance motors (SRMWRs) require accurate rotor position. However, in challenging environments, such as high temperatures and oil contamination, the use of traditional photoelectric, electromagnetic, and magnetic position or speed sensors not only increases system cost and complexity but also reduces reliability and environmental adaptability, limiting the application of SRMWRs. Therefore, sensorless control technology can significantly expand the application range of wide-rotor-tooth bearingless SRMWRs. However, existing positionless control technologies for these motors suffer from complex commutation logic and long commutation times.

[0004] The information disclosed in this background section is only intended to enhance understanding of the overall background of the invention and should not be considered as an admission or any form of suggestion that the information constitutes the prior art already known to a person of ordinary skill in the art. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a position sensorless control method for a single-winding bearingless switched reluctance motor, which solves the defects of the prior art in that the judgment logic is complex and the commutation time is too long during the static starting and running commutation of the motor. The position interval and the excitation phase within the interval are determined by the inductance difference, and then the commutation operation is performed. The overall logic is simple and practical, and the dynamic performance of the motor is effectively improved.

[0006] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0007] The present invention discloses a position sensorless control method for a single-winding bearingless switched reluctance motor, wherein the single-winding bearingless switched reluctance motor is a three-phase motor composed of three-phase windings, comprising the following steps:

[0008] In response to the motor being in a stationary state, a preset first pulse is injected into the three-phase winding of the motor, and by obtaining pulse sampling currents corresponding to the three phases, the inductance difference of the three phases at different sampling periods is calculated; based on the inductance difference, a position interval and an excitation phase within the interval are obtained, and the motor is started;

[0009] In response to the motor being in a starting state, a non-excitation phase in the interval is obtained according to the excitation phase in the interval; a preset second pulse is injected only into the non-excitation phase, and by obtaining a pulse sampling current corresponding to the non-excitation, an inductance difference of different sampling periods of the non-excitation phase is calculated and a commutation operation is performed;

[0010] The reversing operation includes the following steps:

[0011] In response to the inductance difference of the non-excitation phase being less than a preset second threshold, maintaining the existing excitation phase unchanged;

[0012] In response to the inductance difference of the non-excited phase being greater than a preset second threshold, the existing excitation phase is replaced.

[0013] Furthermore, the preset first pulse and second pulse are both high-frequency pulses with a frequency of 200KHZ.

[0014] Furthermore, the three-phase winding includes an A-phase winding, a B-phase winding and a C-phase winding;

[0015] The expression of the inductance difference of the three phases is as follows:

[0016]

[0017]

[0018]

[0019] Where, ΔL A is the inductance difference of phase A; ΔL B is the inductance difference of phase B; ΔL C is the inductance difference of phase C; U S is the preset pulse sampling voltage; ΔT is the first pulse period; ΔT * is the second pulse period; I A is the peak current of phase A sampled in the first pulse cycle; I B is the peak current of phase B sampled in the first pulse cycle; I C is the peak current of phase C sampled in the first pulse cycle; is the peak current of phase A sampled in the second pulse cycle; is the peak current of phase B sampled in the second pulse cycle; is the peak value of the C-phase sampling current in the second pulse cycle.

[0020] Furthermore, there are four adjacent pulse periods between the first pulse period and the second pulse period.

[0021] Furthermore, obtaining the position interval and the excitation phase within the interval according to the inductance difference includes the following steps:

[0022] In response to the inductance difference of phase A being greater than a preset first threshold, the rotor position is located at [-22.5°, -7.5°), the position interval is -1, and when the motor is started, phase A serves as the torque phase and phase B serves as the suspension phase;

[0023] In response to the B-phase inductance difference being greater than a preset first threshold, the rotor position is located at [-7.5°, 7.5°), the position interval is 0, and when the motor is started, phase C serves as the torque phase and phase A serves as the suspension phase;

[0024] In response to the C-phase inductance difference being greater than a preset first threshold, the rotor position is located at [7.5°, 22.5°), the position interval is 1, and when the motor starts, phase B serves as the torque phase and phase C serves as the suspension phase.

[0025] Furthermore, the reversing operation further includes the following steps:

[0026] In response to the non-excitation phase being phase C and the inductance difference of phase C being greater than a preset second threshold, the phase B winding is turned off, the phase A winding and the phase C winding are turned on, so that the phase A winding becomes the suspended phase in the excitation phase and the phase C winding becomes the torque phase in the excitation phase;

[0027] In response to the non-excitation phase being phase B and the inductance difference of phase B being greater than a preset second threshold, the phase A winding is turned off, the phase B winding and the phase C winding are turned on, so that the phase C winding becomes the suspended phase in the excitation phase and the phase B winding becomes the torque phase in the excitation phase;

[0028] In response to the non-excitation phase being phase A and the inductance difference of phase A being greater than a preset second threshold, the phase C winding is turned off, and the phase A winding and the phase B winding are turned on, so that the phase B winding becomes the suspended phase in the excitation phase, and the phase A winding becomes the torque phase in the excitation phase.

[0029] Furthermore, the following steps are included:

[0030] In response to the motor being in the starting state, the motor rotor calculated position angle is obtained according to the position interval, wherein the relationship between the motor rotor calculated position angle is as follows:

[0031]

[0032] Among them, θ represents the calculated position angle of the motor rotor; k represents the rising slope of the inductance; Lu (θ) represents the inductance value corresponding to the angle θ, u represents the phase corresponding to the linear interval i; L n Indicates the minimum inductance; i indicates the corresponding position interval number.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention solves the defects of the prior art in that the judgment logic is complex and the commutation time is too long when the motor is stationary and starting and commutating during operation. When the motor is stationary, a first pulse is injected to obtain the inductance difference, and then the position interval and the excitation phase within the interval are determined; when the motor starts, a second pulse is injected again to obtain the inductance difference of the non-excitation phase, and then the commutation operation is performed. The overall logic is simple and practical, and the dynamic performance of the motor is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a flow chart of a position sensorless control method for a single-winding bearingless switched reluctance motor;

[0036] Figure 2 This is the structural diagram of a 12 / 8 pole single winding wide rotor tooth bearingless switched reluctance motor;

[0037] Figure 3 It is a schematic diagram of the three-phase inductance curve of the motor;

[0038] Figure 4 It is the position where the stator and rotor pole center axes are aligned;

[0039] Figure 5 This is a schematic diagram of the motor A, B, and C three-phase two-phase conduction working mode;

[0040] Figure 6 This is a position determination curve diagram of a single-winding wide-rotor bearingless switched reluctance motor based on an inductance model;

[0041] Figure 7 There are three states of the power converter;

[0042] Figure 8 It is a schematic diagram of high-frequency pulse injection into the non-conducting phase;

[0043] In the figure: 1. Stator; 2. Rotor; 3. Winding. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0045] Example

[0046] This embodiment provides a position sensorless control method for a single-winding bearingless switched reluctance motor. The single-winding bearingless switched reluctance motor is a three-phase motor composed of three-phase windings. Figure 1 As shown, the following steps are included:

[0047] In response to the motor being in a stationary state, a preset first pulse is injected into the three-phase winding of the motor, and by obtaining pulse sampling currents corresponding to the three phases, the inductance difference of the three phases at different sampling periods is calculated; based on the inductance difference, a position interval and an excitation phase within the interval are obtained, and the motor is started;

[0048] In response to the motor being in a starting state, a non-excitation phase in the interval is obtained according to the excitation phase in the interval; a preset second pulse is injected only into the non-excitation phase, and by obtaining the pulse sampling current corresponding to the non-excitation, the inductance difference of the non-excitation phase in different sampling periods is calculated and a commutation operation is performed;

[0049] The reversing operation includes the following steps:

[0050] In response to the inductance difference of the non-excited phase being less than a preset second threshold, maintaining the existing excitation phase unchanged;

[0051] In response to the inductance difference of the non-excited phase being greater than a preset second threshold, the existing excitation phase is replaced.

[0052] The specific steps are as follows:

[0053] The structure of single-winding bearingless switched reluctance motor is as follows: Figure 2 The figure shows a three-phase motor, comprising a stator 1, a rotor 2, and windings 3. The motor consists of three phases, each of which is composed of four stators 1 and four windings 3. There are twelve windings 3 in total, with one winding 3 wound around each stator tooth. Each winding 3 is independent and disconnected from the others. Each phase of winding 3 consists of four coils on stator teeth spaced 90° apart. The magnetic flux in each phase of winding 3 exhibits a NSNS distribution, resulting in the twelve windings 3 forming a three-phase winding with a 30° phase difference.

[0054] Stator 1 has 12 teeth and a salient-pole structure, with a stator pole arc angle of 15 degrees. Rotor 2 has 8 teeth and a salient-pole structure, with a rotor pole arc angle of 30 degrees. Rotor 2 is constructed from laminated silicon steel sheets. Each time a single phase is controlled, the symmetrical or asymmetrical excitation of the four windings is simultaneously controlled, providing torque and levitation for the motor.

[0055] The inductance of the motor coil changes with the rotor position as follows Figure 3 As shown, the alignment position of the stator and rotor pole center axis is defined as the rotor angle β = 0°, and the alignment position is as follows Figure 4As shown in the figure. When the angle β∈[-22.5°, -7.5°], the inductance of phase A is in the rising region, providing positive torque for the motor, while the inductance of phase B is in the flat-top region, providing levitation for the motor. When the angle β∈[-7.5°, 7.5°], the inductance of phase C is in the rising region, providing positive torque for the motor, while the inductance of phase A is in the flat-top region, providing levitation for the motor. When the angle θ∈[7.5°, 22.5°], the inductance of phase B is in the rising region, providing positive torque for the motor, while the inductance of phase C is in the flat-top region, providing levitation for the motor. Therefore, both phases must be conducting simultaneously for the single-winding BSRMWR to operate normally.

[0056] according to Figure 5 As shown, when the A-phase winding provides suspension force, the C-phase winding provides output torque; when the B-phase winding provides suspension force, the A-phase winding provides output torque; when the C-phase winding provides suspension force, the B-phase winding provides output torque.

[0057] according to Figure 6 As shown in the figure, the rotor position is at [-22.5°, -7.5°) with a position interval of -1. At this time, phase A is the torque phase and phase B is the suspension phase. The rotor position is at [-7.5°, 7.5°) with a position interval of 0. At this time, phase C is the torque phase and phase A is the suspension phase. The rotor position is at [7.5°, 22.5°) with a position interval of 1. At this time, phase B is the torque phase and phase C is the suspension phase.

[0058] The three working states of the motor power converter are as follows: Figure 7 As shown, the working state of each phase winding can be determined according to the changing trend of the inductance of each phase winding. Taking phase A as a reference, the other phases are the same as phase A. If the inductance of phase A is in the rising zone within the working range, both switch tubes S1 and S2 are turned on and are in the fast excitation state. If the inductance of phase A is in the flat top zone, S1 is turned on and S2 is turned off, and is in the freewheeling state. If the inductance of phase A is in the falling zone, both S1 and S2 are turned off and are in the demagnetization state.

[0059] Figure 8 The figure shows an example of high-frequency pulse injection using phase A as the idle phase. When the rotor position is [7.5°, 22.5°), phase B is the torque phase, and phase C is the suspension phase. When the rotor position is [-7.5°, 7.5°), phase C is the torque phase, and phase A is the suspension phase. When the rotor position is [-22.5°, -7.5°), phase A is the torque phase, and phase B is the suspension phase.

[0060] The present invention designs a position sensorless control method for a single-winding wide-rotor bearingless switched reluctance motor, such as Figure 1 The specific implementation process is as follows:

[0061] Process 1: When the motor is stationary, a high-frequency pulse with a frequency of 200KHZ is injected into the three-phase winding of the motor and sampled by the current sensor to obtain the corresponding three-phase pulse sampling currents IA, IB, and IC.

[0062] The voltage equation of a single-winding wide-rotor bearingless switched reluctance motor at rest is:

[0063]

[0064] When injecting a high-level pulse, the resistance and back electromotive force can be ignored, and the equation can be simplified to:

[0065]

[0066] The above equation can be converted to:

[0067]

[0068] Where I u is the pulse sampling current, U S is the set pulse sampling voltage, R is the resistance in each phase, L(θ) is the inductance value corresponding to the current angle, and ω is the current angular velocity of the motor.

[0069] The pulse currents of the three phases are obtained by sampling the current sensors, and the inductance value L(θ) corresponding to the current angle is obtained using the above formula.

[0070] Process 2: Based on the pulse sampling current I obtained in step 1 u , and the set pulse sampling voltage U S , calculate the three-phase corresponding inductance difference ΔL A , ΔL B , ΔL C , and record the maximum value of the inductance L obtained by phase sampling m , the minimum value of inductance L n Used to verify the accuracy of process 5. Corresponding to the three-phase inductance difference ΔL A , ΔL B , ΔL C The expression is as follows:

[0071]

[0072]

[0073]

[0074] ΔT * =ΔT+4ΔT

[0075] Where, ΔL A is the inductance difference of phase A; ΔLB is the inductance difference of phase B; ΔL C is the inductance difference of phase C; U S is the preset pulse sampling voltage; ΔT is the first pulse period; ΔT * is the second pulse period; I A is the peak current of phase A sampled in the first pulse cycle; I B is the peak current of phase B sampled in the first pulse cycle; I C is the peak current of phase C sampled in the first pulse cycle; is the peak current of phase A sampled in the second pulse cycle; is the peak current of phase B sampled in the second pulse cycle; is the peak value of the C-phase sampling current in the second pulse cycle.

[0076] In this embodiment, there are four adjacent pulse periods between the first pulse period and the second pulse period.

[0077] Process 3: Based on the three-phase inductance difference ΔL A , ΔL B , ΔL C The motor starts when the size and position interval are determined, as well as the excitation phase within the interval. The judgment rules are as follows:

[0078] Inductance difference Rotor position Position interval Excitation phase <![CDATA[ΔL A >0]]> [-22.5°，-7.5°) -1 A phase torque, B phase suspension <![CDATA[ΔL B >0]]> [-7.5°，7.5°) 0 C phase torque, A phase suspension <![CDATA[ΔL C >0]]> [7.5°，22.5°) 1 B phase torque, C phase suspension

[0079] In this embodiment, the preset first threshold is 0, and the specific judgment rules are as follows:

[0080] If the inductance difference ΔL A >0, the rotor position is between [-22.5°, -7.5°), and the position interval is -1. At this time, phase A serves as the torque phase and phase B serves as the suspension phase.

[0081] If the inductance difference ΔL b >0, the rotor position is at [-7.5°, 7.5°), the position interval is 0, at this time, phase C is used as the torque phase, and phase A is used as the suspension phase.

[0082] If the inductance difference ΔL C >0, the rotor position is at [7.5°, 22.5°), the position interval is 1, at this time, phase B is used as the torque phase, and phase C is used as the suspension phase.

[0083] Process 4: Using the excitation phase within the interval determined in process 3, high-frequency pulses are injected only into the non-excitation phase. The relationship between the inductance difference of the non-excitation phase and the threshold value 0 is determined to perform the commutation operation. The specific operations are as follows:

[0084] If the current excitation phase is phase A providing torque and phase B providing suspension, then only a high-frequency pulse with a pulse frequency of 200KHZ is injected into the non-excitation phase C to determine ΔL C With the threshold value 0, if ΔL C <0, keep the existing excitation phase unchanged, if ΔL C >0, the B-phase winding is turned off, and the A-phase winding and the C-phase winding are turned on, so that the A-phase winding becomes the suspension phase in the excitation phase and the C-phase winding becomes the torque phase in the excitation phase;

[0085] If the current excitation phase is C phase providing torque and A phase providing suspension, then only a high-frequency pulse with a pulse frequency of 200KHZ is injected into the non-excitation phase B phase to determine ΔL B With the threshold value 0, if ΔL B <0, keep the existing excitation phase unchanged, if ΔL B >0, the A-phase winding is turned off, and the B-phase winding and the C-phase winding are turned on, so that the C-phase winding becomes the suspension phase in the excitation phase and the B-phase winding becomes the torque phase in the excitation phase;

[0086] If the current excitation phase is phase B providing torque and phase C providing suspension, then only a high-frequency pulse with a pulse frequency of 200KHZ is injected into the non-excitation phase A to determine ΔL A With the threshold value 0, if ΔL A <0, keep the existing excitation phase unchanged, if ΔL A >0, the C-phase winding is turned off, and the A-phase winding and the B-phase winding are turned on, so that the B-phase winding becomes the suspension phase in the excitation phase and the A-phase winding becomes the torque phase in the excitation phase.

[0087] Process 5: Based on the position interval obtained in process 3, calculate the current position angle of the motor and obtain the calculated position angle of the motor rotor; then compare it with the actual position angle of the motor rotor measured by the Hall sensor to verify the accuracy of this solution.

[0088] The inductance value is calculated as follows:

[0089] L u (θ)=k(θ-(15i-7.5))+L n (i=-1, 0, 1; u=A, C, B)

[0090]

[0091] The calculation formula for the motor rotor position angle is derived as follows:

[0092]

[0093] Among them, β represents the calculated position angle of the motor rotor; k represents the rising slope of the inductance; Lu (θ) represents the inductance value corresponding to the angle θ, u represents the phase corresponding to the linear interval i; L m and L n It represents the maximum and minimum values of the inductance measured in process 2; i represents the corresponding position interval number;

[0094] The test shows that the error between the estimated position angle and the actual position angle is within 4.8%, which proves the feasibility of the scheme.

[0095] From the above description, it can be seen that according to a position sensorless control method and specific implementation steps of a single-winding wide-rotor bearingless switched reluctance motor, the position angle of the motor when it is stationary and running can be effectively estimated without increasing hardware costs.

[0096] This method studies the unique characteristics of the motor's inductance model. When the motor is stationary, it compares the difference in the three-phase inductance to determine the current rotor region and excitation phase. When the motor is running, it injects high-frequency pulses into the non-conducting phase, calculating the difference between the inductance of the non-conducting phase and a threshold of 0 as the commutation logic. This method is simple and practical, and can improve the system's dynamic performance.

[0097] By theoretically analyzing and deducing the winding inductance characteristic curve, an equation-based ratio relationship between the inductance value at rest and the current position angle is derived. This is then combined with the current magnitude of the three-phase non-conducting phase to perform zoning control and determine the current angular position. When the motor is running at low or medium speeds, the inductance difference of the non-conducting phase is used as the motor commutation signal. This invention eliminates the need to query an inductance-position table to obtain the real-time position angle and compare the real-time inductance with the inductance at the commutation position to implement the commutation control process. This results in faster motor startup commutation speeds. This method does not require additional hardware circuitry, and the algorithm is simple and feasible.

[0098] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0099] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0100] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0101] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0102] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A position sensorless control method for a single-winding bearingless switched reluctance motor, wherein the single-winding bearingless switched reluctance motor is a three-phase motor composed of three-phase windings, characterized in that: The steps include: In response to the motor being in a stationary state, a preset first pulse is injected into the three-phase winding of the motor, and by obtaining pulse sampling currents corresponding to the three phases, the inductance difference of the three phases at different sampling periods is calculated; based on the inductance difference, a position interval and an excitation phase within the interval are obtained, and the motor is started; In response to the motor being in a starting state, a non-excitation phase in the interval is obtained according to the excitation phase in the interval; a preset second pulse is injected only into the non-excitation phase, and by obtaining a pulse sampling current corresponding to the non-excitation, an inductance difference of different sampling periods of the non-excitation phase is calculated and a commutation operation is performed; The reversing operation includes the following steps: In response to the inductance difference of the non-excitation phase being less than a preset second threshold, maintaining the existing excitation phase unchanged; In response to the inductance difference of the non-excited phase being greater than a preset second threshold, replacing the existing excitation phase; The three-phase winding includes an A-phase winding, a B-phase winding and a C-phase winding; The expression of the inductance difference of the three phases is as follows: ； ； ； in, is the inductance difference of phase A; is the inductance difference of phase B; is the inductance difference of phase C; is the preset pulse sampling voltage; is the first pulse cycle; is the second pulse period; is the peak current of phase A sampled in the first pulse cycle; is the peak current of phase B sampled in the first pulse cycle; is the peak current of phase C sampled in the first pulse cycle; is the peak current of phase A sampled in the second pulse cycle; is the peak current of phase B sampled in the second pulse cycle; is the peak current of phase C sampled in the second pulse cycle; Obtaining a position interval and an excitation phase within the interval according to the inductance difference includes the following steps: In response to the inductance difference of phase A being greater than a preset first threshold, the rotor position is located at [-22.5°, -7.5°), with a position interval of -1. When the motor is started, phase A serves as the torque phase and phase B serves as the suspension phase. In response to the B-phase inductance difference being greater than a preset first threshold, the rotor position is located at [-7.5°, 7.5°), the position interval is 0, and when the motor is started, phase C serves as the torque phase and phase A serves as the suspension phase; In response to the C-phase inductance difference being greater than a preset first threshold, the rotor position is located at [7.5°, 22.5°), the position interval is 1, and when the motor starts, phase B serves as the torque phase and phase C serves as the suspension phase.

2. The position sensorless control method for a single-winding bearingless switched reluctance motor according to claim 1, wherein: The preset first pulse and second pulse are both high-frequency pulses with a frequency of 200KHZ.

3. The position sensorless control method for a single-winding bearingless switched reluctance motor according to claim 1, wherein: There are four adjacent pulse periods between the first pulse period and the second pulse period.

4. The position sensorless control method for a single-winding bearingless switched reluctance motor according to claim 1, wherein: The reversing operation further comprises the following steps: In response to the non-excitation phase being phase C and the inductance difference of phase C being greater than a preset second threshold, the phase B winding is turned off, the phase A winding and the phase C winding are turned on, so that the phase A winding becomes the suspended phase in the excitation phase and the phase C winding becomes the torque phase in the excitation phase; In response to the non-excitation phase being phase B and the inductance difference of phase B being greater than a preset second threshold, the phase A winding is turned off, the phase B winding and the phase C winding are turned on, so that the phase C winding becomes the suspended phase in the excitation phase and the phase B winding becomes the torque phase in the excitation phase; In response to the non-excitation phase being phase A and the inductance difference of phase A being greater than a preset second threshold, the phase C winding is turned off, and the phase A winding and the phase B winding are turned on, so that the phase B winding becomes the suspended phase in the excitation phase, and the phase A winding becomes the torque phase in the excitation phase.

5. The position sensorless control method for a single-winding bearingless switched reluctance motor according to claim 1, wherein: The following steps are also included: In response to the motor being in the starting state, the motor rotor calculated position angle is obtained according to the position interval, wherein the relationship between the motor rotor calculated position angle is as follows: ； in, Indicates the calculated position angle of the motor rotor; k represents the rising slope of the inductance; Indicates angle The corresponding inductance value, u represents the corresponding phase in the linear interval i; Indicates the minimum inductance; i indicates the corresponding position interval number.

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