Six-phase switched reluctance motor sensorless rotor position estimation method and system

Abstract

The application discloses a six-phase switched reluctance motor and a position sensorless rotor position estimation method and system, the six-phase switched reluctance motor comprises a stator assembly and a rotor assembly, the stator assembly comprises a stator core, the stator core comprises stator teeth and a stator yoke, and windings are arranged on the stator teeth; the number of the stator teeth Ns is a multiple of 6, six adjacent windings form six-phase windings, the six-phase windings are provided with a plurality of groups, one end of each group of the six-phase windings is communicated with each other to form a common end, and the other end is connected to a controller interface. The application improves the wiring mode and the motor structure of the six-phase switched reluctance motor, reduces the number of outgoing lines of the motor by arranging the common end, reduces the complexity of winding and outgoing line, and reduces the cost.

Description

Technical Field

[0001] This invention relates to the field of reluctance motor technology, and in particular to a six-phase switched reluctance motor and a method and system for estimating rotor position without position sensors. Background Technology

[0002] Switched reluctance motors (SRMs) are a new type of speed-regulating motor, primarily used in speed control systems to convert electromechanical energy. Common SRMs are mainly doubly salient pole motors, with the stator and rotor salient poles primarily made of silicon steel sheets or copper. They do not require permanent magnets, offering advantages such as simple structure and low cost. Furthermore, they completely avoid the negative impact of permanent magnet demagnetization on motor performance, making them widely applicable across various fields. Generally, the rotor of a switched reluctance motor has neither windings nor permanent magnets, while the stator has windings. The operation of a switched reluctance motor primarily relies on changes in rotor position to determine the on / off state of the phase windings. Therefore, the reliability and precision of obtaining a rotor position directly determine the performance of the switched reluctance motor.

[0003] In existing technologies, methods for obtaining rotor position mainly include: sensor-based and sensorless methods. Sensor-based methods use position sensors to detect rotor position. Common position sensors used with switched reluctance motors include Hall effect sensors, photoelectric encoders, and rotary transformers. However, the use of position sensors increases the assembly difficulty and cost of the motor system. Moreover, in some harsh operating conditions, the accuracy and reliability of position sensors are low, affecting the normal operation of the motor system. Sensorless methods are mainly applied to switched reluctance motors and include: current flux linkage method, inductance observer method, and intelligent control method. However, these methods suffer from problems such as large data volume, lack of portability, and low reliability. For example, the current flux linkage method mainly utilizes the salient pole effect of switched reluctance motors. Since the current-flux linkage curves are inconsistent at different rotor positions, a large number of current-flux linkage characteristic curves need to be collected and analyzed to obtain relatively accurate results. The method has poor portability and increases the statistical workload. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a six-phase switched reluctance motor and a sensorless rotor position estimation method and system. By setting a common terminal, the number of motor leads is reduced, lowering the complexity of winding and wiring, and reducing costs. Furthermore, the sensorless calculation method eliminates the need for pre-measuring large amounts of flux linkage-current data, reducing computational load, improving stability, and enhancing the accuracy of position estimation.

[0005] To achieve the above objectives, firstly, the present invention provides a six-phase switched reluctance motor, including a stator assembly and a rotor assembly, characterized in that the stator assembly includes a stator core, the stator core includes stator teeth and a stator yoke, and the stator teeth are provided with windings;

[0006] The number of stator teeth Ns is a multiple of 6. Six adjacent windings constitute a six-phase winding. The six-phase winding is provided in several groups. One end of each group of six-phase windings is connected to each other to form a common terminal, and the other end is connected to the controller interface.

[0007] Preferably, the relationship between the number of stator teeth Ns and the number of rotor teeth Nr satisfies: .

[0008] Preferably, the six-phase winding method is NNNNNN or SSSSSS or NSNSNS or NNSSNN or NNNSSS, where N represents the winding in a clockwise direction and S represents the winding in a counterclockwise direction.

[0009] Preferably, when the number of stator teeth Ns is 12, the six-phase winding method is NNNNNN or SSSSSS.

[0010] Preferably, the stator yoke includes at least hsy0 and hsy1 regions of unequal width, and the hsy0 and hsy1 regions are arranged at intervals along the circumferential direction of the stator yoke.

[0011] Preferably, the six-phase switched reluctance motor is configured as an external rotor motor, an internal rotor motor, a linear motor, a disc motor, a cascaded motor, or a non-standard motor.

[0012] Preferably, the stator assembly and / or the rotor assembly are provided with auxiliary permanent magnets and / or electrically excited windings.

[0013] Preferably, the stator core has a salient pole structure; the rotor assembly includes a rotor core, which also has a salient pole structure.

[0014] In addition, the present invention also provides a sensorless rotor position estimation method using the above-mentioned six-phase switched reluctance motor, which includes:

[0015] The current and voltage values ​​in the six-phase winding are collected, and the control waveform in the six-phase winding is a square wave, a sine wave, or a part of a sine wave;

[0016] The flux linkage value is calculated by collecting the current and voltage values;

[0017] The actual position and operating speed of the rotor assembly are estimated by using current, voltage, and flux linkage values.

[0018] Furthermore, the present invention also provides a sensorless rotor position estimation system for a six-phase switched reluctance motor, comprising:

[0019] The data acquisition module is used to acquire the current and voltage values ​​in the six-phase windings. The control waveform in the six-phase windings is a square wave, a sine wave, or a part of a sine wave.

[0020] The data processing module calculates the flux linkage value based on the collected current and voltage values;

[0021] The inductance calculation module estimates the actual position and operating speed of the rotor assembly using current, voltage, and flux linkage values.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] The six-phase switched reluctance motor provided in the above technical solution reduces the number of motor leads, lowers the complexity of winding and lead-out, and reduces costs. In addition, the sensorless rotor position estimation method of the present invention collects the voltage and current of the six-phase windings through a data acquisition module, calculates the flux linkage of the phase windings through a data processing module, and estimates the actual position and actual running speed of the rotor through an inductance calculation module. It has low computational load, high stability, and accurate position estimation. Moreover, due to the increase in the number of phases, the torque fluctuation and noise of the motor are significantly reduced, making it suitable for a wide range of applications. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a twelve-stator-tooth six-phase switched reluctance motor, the connection method of the windings and the controller, provided in an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the structure, winding, and controller connection of a traditional twelve-stator-tooth six-phase switched reluctance motor.

[0026] Figure 3 This is a schematic diagram of a coil winding combination method provided in an embodiment of the present invention.

[0027] Figure 4 Various optional motor structure diagrams are provided for embodiments of the present invention.

[0028] Figure 5 The diagram shows the structure of a six-phase switched reluctance motor with a stator yoke that is not uniformly arranged along the circumferential direction, as provided in an embodiment of the present invention.

[0029] Figure 6 A flowchart for sensorless rotor position estimation provided in an embodiment of the present invention.

[0030] Figure 7 The test dynamometer data curve and specific data table are provided for embodiments of the present invention.

[0031] Reference numerals: 1. Stator assembly; 11. Stator yoke; 12. Stator tooth; 2. Rotor assembly; 3. Winding. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0033] It should be noted that the terms "first" and "second" used in the embodiments of the present invention are for descriptive purposes only and should not be construed as indicating or implying the number of technical features defined therein. Therefore, features defined with "first" and "second" in the embodiments of this specification can indicate that at least one of the defined technical features is included.

[0034] See Figure 1 The six-phase switched reluctance motor proposed in this invention includes a stator assembly 1 and a rotor assembly 2. The stator assembly 1 includes a stator core, which includes stator teeth 12 and a stator yoke 11. The rotor assembly 2 includes a rotor core. Both the stator core and the rotor core have salient pole structures. Windings 3 are provided on the stator teeth 12, and the number of stator teeth 12, Ns, is a multiple of 6. Six adjacent windings 3 constitute a six-phase winding 3. Several groups of six-phase windings 3 are provided, with one end of each group of six-phase windings 3 interconnected to form a common terminal, and the other end connected to a controller interface.

[0035] In this embodiment, the motor corresponding to every six windings 3 can be set as the smallest unit motor. When the number of stator teeth Ns is greater than 6, every six windings 3 is one phase, for a total of six phases.

[0036] In a preferred embodiment, the relationship between the number of stator teeth Ns and the number of rotor teeth Nr satisfies: .

[0037] In one embodiment of the present invention, taking a 12-stator-tooth 12-phase switched reluctance motor as an example, each coil is wound on the stator tooth 12, and the six adjacent windings 3 along the circumference belong to the six phases A, B, C, D, E, and F respectively. Two radially opposite windings 3 are the same phase. One end of the six-phase windings 3 is connected to each other to form a common end, and the other end is connected to the controller interface.

[0038] See Figure 2Taking a traditional 12-stator-tooth, 12-phase switched reluctance motor as an example, each coil is wound on a stator tooth 12, with adjacent coils arranged alternately in winding direction. The six adjacent windings 3 along the circumference belong to phases A, B, C, D, E, and F, respectively. Two radially opposite windings 3 belong to the same phase, and the leads at both ends of each phase are connected to the controller. Compared to the traditional 12-tooth, 12-phase switched reluctance motor, the 12-tooth, 12-phase switched reluctance motor of this invention reduces the number of leads from 12 to 6 by introducing a common terminal, thus reducing the complexity of the wiring and the cost of the controller.

[0039] See Figure 3 The six-phase winding 3 within the unit motor exhibits diverse winding patterns, meaning there are multiple combinations of winding directions for adjacent coils. Specifically, assuming "N" represents winding 3 in a clockwise direction and "S" represents winding 3 in a counter-clockwise direction, the winding combination patterns include "NNNNNNN", "SSSSSS", "NSNSNS", "NNSSNN", and "NNNSSS". Figure 3 -a is a schematic diagram of the "NNNNNNN" or "SSSSSS" winding method. Figure 3 -b is a diagram illustrating the "NSNSNS" winding method. Figure 3 -c is a schematic diagram of the "NNSSNN" winding method. Figure 3 -d is a schematic diagram of the "NNNSSS" winding method.

[0040] See Figure 4 A six-phase switched reluctance motor can be configured as an external rotor motor, an internal rotor motor, a linear motor, a disc motor, a cascaded motor, or a non-standard motor. Among these, Figure 4 -a is an 18-stator tooth 12-outer rotor motor; Figure 4 -b indicates a 12-tooth non-standard motor with six stator teeth; Figure 4 -c indicates a 12-axis multi-axis motor with twelve stator teeth; Figure 4 -d represents a cascaded motor, consisting of two stators (upper and lower) and two rotors, with a total of twelve stator teeth in the entire motor system.

[0041] See Figure 5, the stator yoke 11 comprises at least an hsy0 region and an hsy1 region, wherein the hsy0 region and the hsy1 region are arranged at intervals along the circumferential direction of the stator yoke. Specifically, the width of the stator yoke 11 can be reduced every one tooth or a plurality of teeth apart, that is, hsy1<hsy0. Preferably, the proportional relationship between the two is hsy1=1 / 2 hsy0. In other embodiments, the stator yoke 11 may also comprise more than two regions with different widths, such as an hsy0 region, an hsy1 region and an hsy2 region, and the width relationship thereof is hsy2<hsy1<hsy0. Through the above arrangement, the weight of the stator core can be reduced without affecting the performance of the motor. In addition, the step-shaped stator core is more conducive to fixation during assembly.

[0042] In other embodiments, an auxiliary permanent magnet or an electric excitation winding 3 may also be provided on the stator assembly 1, or an auxiliary permanent magnet or an electric excitation winding 3 may be provided on the rotor assembly 2.

[0043] Based on the above six-phase switched reluctance motor, the present invention also provides a sensorless rotor position estimation method and system for a six-phase switched reluctance motor, as Figure 6 described, which specifically comprises:

[0044] (1) a data acquisition module, configured to acquire current values and voltage values in the six-phase windings 3, wherein a control waveform in the six-phase windings 3 is a square wave, a sine wave or a part of a sine wave;

[0045] (2) a data processing module, which calculates a flux linkage value through the acquired current values and voltage values;

[0046] (3) an inductance calculation module, which estimates the actual position and operating speed of the rotor assembly 2 through the current values, voltage values and flux linkage values.

[0047] Specifically, the data acquisition module acquires voltage values and current values at the connection between the six-phase windings 3 and a controller in real time through current sampling and voltage sampling; the data acquisition module is in communication with the data processing module, and the data processing module converts six-phase signals into signals in a two-phase α-β stationary coordinate system through coordinate transformation; the data processing module is in communication with the inductance calculation module, and the inductance calculation module calculates inductance in the two-phase α-β stationary coordinate system. Since the inductance in the two-phase α-β stationary coordinate system is related to the position of the motor, the real-time position of the rotor can be estimated, and then the real-time rotation speed of the motor can be estimated by deriving the rotor position.

[0048] The systems and modules described in the above embodiments can be implemented by computer chips or physical entities, or by products with certain functions. A typical implementation device is a computer. Specifically, a computer can be, for example, a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices. For ease of description, the above systems are described by dividing them into various modules according to their functions. Of course, in implementing this invention, the functions of each module can be implemented in one or more software and / or hardware.

[0049] The voltage equation for the six-phase switched reluctance motor can be expressed as follows:

[0050] (1)

[0051] in, , , , , These are the applied voltage, resistance, current, induced electromotive force, and flux linkage of the k-th phase winding, respectively.

[0052] The six-phase signal in natural coordinates is converted to a two-phase α-β stationary coordinate system using a coordinate transformation method.

[0053] (2)

[0054] Where f is a signal, including voltage, current, magnetic flux linkage signal, inductance signal, resistance signal, and induced electromotive force signal, and f α f b f c f d f e f f It transforms a two-phase α-β stationary coordinate system signal into six signals on a six-phase system using a transformation matrix. for:

[0055] (3)

[0056] Therefore, by sampling the current and voltage of the six-phase windings and transforming the six-phase to two-phase coordinates, the coordinates in the two-phase α-β stationary coordinate system can be calculated. , , , , and U α U β i α i βThese are the components of voltage sampling and current sampling in the α-β phase stationary coordinate system, respectively.

[0057] In the two-phase α-β stationary coordinate system:

[0058] (4)

[0059] Therefore, there is

[0060] (5)

[0061] (6)

[0062] The resistance R in equations (5) and (6) can be directly measured, therefore e α e β The phase α-β stationary coordinate system can be directly integrated. , , and e α e β These are the components of the induced electromotive force in the α-β phase stationary coordinate system, and Ψ are the components of the induced electromotive force. α Ψ β These are the components of the magnetic flux in the α-β phase stationary coordinate system.

[0063] also, , It can also be expressed as:

[0064] (7)

[0065] in, This is the phase winding inductance when the stator salient pole and the rotor groove center coincide. These are variable parameters, which are related to the motor's structure, rotor position, current magnitude, and core saturation level.

[0066] Solve equations (5), (6), and (7) simultaneously to eliminate the unknowns. The rotor position can be calculated as follows:

[0067] (8)

[0068] The rotor position angle can be obtained from this. Regarding the rotor position angle By taking the first derivative, we can obtain the velocity at the rotor's position. .

[0069] (9)

[0070] Figure 7After employing the aforementioned sensorless rotor position estimation method, the physical prototype was tested on a dynamometer, yielding a detailed data table and dynamometer curve. Its highest efficiency point was 88.4%, while the highest efficiency point of a sensor-equipped surface-mounted permanent magnet motor in the same application was 85%. This verifies the feasibility and superior performance of the proposed six-phase switched reluctance motor and sensorless rotor position estimation method.

[0071] This invention improves the wiring method and motor structure of a six-phase switched reluctance motor. It uses a data acquisition module to sample the voltage and current in the six-phase windings in real time, a data processing module to calculate the flux linkage, and an inductance calculation module to estimate the rotor position. It has the advantages of simple structure, easy implementation, high practicality, high calculation accuracy, and high reliability.

[0072] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A six-phase switched reluctance motor, comprising a stator assembly and a rotor assembly, characterized in that, The stator assembly comprises a stator core, which includes stator teeth and a stator yoke, and a winding is arranged on the stator teeth; The number of stator teeth Ns is a multiple of 6, six adjacent windings form a six-phase winding, a plurality of groups of the six-phase winding are provided, one ends of each group of the six-phase winding are communicated with each other to form a common end, and the other ends are all connected to a controller interface; The stator yoke at least includes an hsy0 region and an hsy1 region with different widths, and the hsy0 region and the hsy1 region are arranged at intervals along the circumferential direction of the stator yoke; The width of the hsy1 region is smaller than the width of the hsy0 region, and the proportional relationship between the two is that the width of the hsy1 region = 1 / 2 of the width of the hsy0 region; Estimating the actual position and operating speed of the rotor assembly through the current value, voltage value and flux linkage value; Wherein, the voltage equation of the six-phase switched reluctance motor is expressed as follows: （1） Among them, U k R k i k e k Ψ k These are the applied voltage, resistance, current, induced electromotive force, and flux linkage of the k-th phase winding, respectively. A coordinate transformation method is used to convert the six-phase signals in natural coordinates to a two-phase α-β stationary coordinate system; （2） Where f is a signal, including voltage, current, magnetic flux linkage signal, inductance signal, resistance signal, and induced electromotive force signal, and f α f b f c f d f e f f It transforms a two-phase α-β stationary coordinate system signal into six signals on a six-phase system, using the transformation matrix T. αβ for: （3） Therefore, by sampling the current and voltage of the six-phase windings and using a six-phase to two-phase coordinate transformation, U in the two-phase α-β stationary coordinate system can be calculated. α U β i α i β , and U α U β i α i β These are the components of voltage sampling and current sampling in the α-β phase stationary coordinate system, respectively. In the two-phase α-β stationary coordinate system: （4） Therefore, we have （5） （6） The resistance R in equations (5) and (6) is obtained directly by measurement, therefore e α e β Direct integration of Ψ in the phase α-β stationary coordinate system α Ψ β , and e α e β These are the components of the induced electromotive force in the α-β phase stationary coordinate system, and Ψ are the components of the induced electromotive force. α Ψ β These are the components of the magnetic flux in the α-β phase stationary coordinate system, respectively; In addition, Ψ α Ψ β It can also be expressed as: （7） Among them, L u L(θ)k is the phase winding inductance when the stator salient pole and the rotor groove center coincide. s These are variable parameters, which are related to the motor's structure, rotor position, current magnitude, and core saturation level. Simultaneous equations (5), (6) and (7) eliminate the unknown k s The rotor position can be calculated as follows: （8） Wherein, the rotor position angle θ is obtained, and the first derivative of the rotor position angle θ is calculated to obtain the rotor position speed ω; （9）。 2. A six-phase switched reluctance motor as described in claim 1, characterized in that, The relationship between the number of stator teeth Ns and the number of rotor teeth Nr satisfies: .

3. A six-phase switched reluctance motor as described in claim 1, characterized in that, The winding mode of the six-phase winding is NNNNNN, SSSSSS, NSNSNS, NNSSNN or NNNSSS, wherein N represents that the winding is along the clockwise direction, and S represents that the winding is along the counterclockwise direction.

4. A six-phase switched reluctance motor as described in claim 3, characterized in that, When the number of stator teeth Ns is 12, the winding mode of the six-phase winding is NNNNNN or SSSSSS.

5. A six-phase switched reluctance motor as described in claim 1, characterized in that, The six-phase switched reluctance motor is configured as an outer rotor motor, an inner rotor motor, a linear motor, a disc motor, a cascade motor or a special-shaped motor.

6. A six-phase switched reluctance motor as described in claim 1, characterized in that, An auxiliary permanent magnet and / or an electric excitation winding is arranged on the stator assembly and / or the rotor assembly.

7. A six-phase switched reluctance motor as described in claim 1, characterized in that, The stator core has a salient pole structure; the rotor assembly comprises a rotor core, and the rotor core also has a salient pole structure.

8. A method for estimating the rotor position of a six-phase switched reluctance motor without a position sensor, implemented using a six-phase switched reluctance motor as described in any one of claims 1-7, characterized in that... Comprising: Collecting the current value and voltage value in the six-phase winding, wherein the control waveform in the six-phase winding is a square wave, a sine wave or a part of a sine wave; Calculating the flux linkage value through the collected current value and voltage value; Estimating the actual position and operating speed of the rotor assembly through the current value, voltage value and flux linkage value.

9. A sensorless rotor position estimation system for a six-phase switched reluctance motor, characterized in that, Based on the six-phase switched reluctance motor according to any one of claims 1 to 7, comprising: A data acquisition module, configured to collect the current value and voltage value in the six-phase winding, wherein the control waveform in the six-phase winding is a square wave, a sine wave or a part of a sine wave; A data processing module, configured to calculate the flux linkage value through the collected current value and voltage value; An inductance calculation module, configured to estimate the actual position and operating speed of the rotor assembly through the current value, voltage value and flux linkage value.

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