A motor rotating speed switching system and method applied to a speed sensorless electric drive system

Abstract

This invention provides a motor speed switching system and method for sensorless electric drive systems, relating to the field of motor control technology. It includes: an acquisition module for acquiring rotor position estimation information obtained after injecting a high-frequency voltage signal into the motor; a first processing module for establishing a hybrid flux linkage observation model, including a current model, a PI controller, and a voltage model; the current model for calculating first flux linkage information based on the current signal and rotor position estimation information; the voltage model for receiving the first flux linkage information through the output of the PI controller, calculating second flux linkage information using back electromotive force, and fusing and outputting third flux linkage information; and the PI controller for processing the output of the current model and inputting it to the voltage model, while simultaneously receiving the third flux linkage information, dynamically controlling and iteratively adjusting the third flux linkage information to obtain rotor position observation information for smooth speed switching. This solves the problem of high safety risks associated with the inability to smoothly switch speeds in existing sensorless systems.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a motor speed switching system and method for use in sensorless electric drive systems. Background Technology

[0002] Sensorless speed control plays a crucial role in motor drive systems. It replaces physical sensors with algorithmic estimation, using algorithms to estimate rotor position and speed in real time. This offers significant advantages such as low cost, high reliability, and ease of maintenance. This technology has been widely applied in industrial frequency converters, electric vehicle drives, and motor control.

[0003] Existing sensorless solutions commonly used in motor control systems include high-frequency signal injection methods suitable for zero-speed and low-speed scenarios, or back EMF observation methods suitable for medium- and high-speed applications. However, in order to meet the requirements of full-speed-range operation, multiple solutions are considered to be used in combination in some scenarios. However, how to switch between them is the key to stable operation in the full-speed-range. If the switch is made directly, it may cause a jump in speed / position estimation, causing matrix fluctuations. Furthermore, the signals generated by different solutions may interfere with each other, thereby affecting control accuracy and posing a high safety risk. Summary of the Invention

[0004] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide a motor speed switching system and method for use in a sensorless electric drive system, so as to solve the problem that the speed cannot be smoothly switched in the existing sensorless system, which easily leads to speed jumps and poses a high safety risk.

[0005] This invention discloses a motor speed switching system for sensorless electric drive systems, comprising:

[0006] The acquisition module acquires rotor position estimation information obtained after injecting a high-frequency voltage signal into the motor;

[0007] The first processing module establishes a hybrid flux observation model, including a current model, a PI controller, and a voltage model.

[0008] The current model calculates the first flux linkage information based on the current signal and the rotor position estimation information.

[0009] The voltage model receives the first flux linkage information through the output of the PI controller, calculates the second flux linkage information by integrating the back electromotive force, and outputs the third flux linkage information by integrating and fusing the components.

[0010] The PI controller is connected to the current model and the voltage model. It processes the output of the current model and inputs it to the voltage model. At the same time, it receives the third flux linkage information fed back by the voltage model to dynamically allocate the weights corresponding to the first flux linkage information and the second flux linkage information in the third flux linkage information. This allows for iterative adjustment of the third flux linkage information and the acquisition of rotor position observation information for smooth speed switching.

[0011] Preferably, it includes a conversion module that calculates rotor position observation information using an arctangent function based on the third flux linkage information.

[0012] Preferably, it includes a second processing module for calculating rotor position estimation information after injecting a high-frequency voltage signal into the motor.

[0013] This invention also discloses a method for switching motor speed in a sensorless electric drive system, comprising:

[0014] Obtain rotor position estimation information calculated by injecting a high-frequency voltage signal into the motor;

[0015] A hybrid flux observation model is established, including a current model, a PI controller, and a voltage model;

[0016] The first flux linkage information is calculated using a current model based on the current signal and the rotor position estimation information.

[0017] The first flux linkage information is output to the voltage model through a PI controller. The second flux linkage information is calculated using the back electromotive force integration within the voltage model. The third flux linkage information is output through integration and fusion.

[0018] Simultaneously, the third flux linkage information is fed back to the PI controller, enabling the PI controller to dynamically allocate the weights corresponding to the first and second flux linkage information in the fused flux linkage information, thereby iteratively adjusting the third flux linkage information to obtain rotor position observation information based on the third flux linkage information for smooth speed switching.

[0019] Preferably, the PI controller dynamically allocates the weights corresponding to the first and second flux linkage information in the fused flux linkage information, and controls the process according to the following allocation function:

[0020] ;in To integrate magnet link information; This is the first magnet link information; This is the second magnetic link information; , These are the preset parameters for the PI controller.

[0021] Preferably, a first function is established by outputting the PI controller based on the difference between the first flux linkage information and the third flux linkage information;

[0022] The second function is established by performing an integral operation based on the sum of the PI controller output and the back electromotive force to output the third flux linkage information.

[0023] A third function is established by outputting the second flux linkage information based on the back electromotive force integral calculation;

[0024] The allocation function is obtained by solving the first function, the second function, and the third function.

[0025] Preferably, it includes:

[0026] A high-frequency voltage signal is injected into the motor to obtain the high-frequency current component of the motor response;

[0027] The rotor position estimation information is calculated based on the high-frequency current component extracted by a bandpass filter and PI control.

[0028] Preferably, the amplitude of the high-frequency voltage signal is adjusted to control the start and stop of the hybrid flux observation model.

[0029] Preferably, when the motor is at a predetermined low speed, the PI controller adjusts the weight corresponding to the first flux linkage information to 1 and the weight corresponding to the second flux linkage information to 0.

[0030] When the motor is at the predetermined high speed, the PI controller adjusts the weight corresponding to the second flux linkage information to 1 and the weight corresponding to the first flux linkage information to 0.

[0031] When the motor is in the low-speed to high-speed transition, the PI controller dynamically allocates the weights corresponding to the first flux linkage information and the second flux linkage information in the fused flux linkage information.

[0032] Preferably, the rotor position observation information is calculated using the arctangent function based on the third flux linkage information.

[0033] Compared with existing technologies, the above technical solution has the following advantages:

[0034] The motor speed switching system and method provided in this application for sensorless electric drive systems constructs a hybrid flux linkage observation model in the first processing module. The rotor position estimation information obtained by injecting a high-frequency signal into the motor is injected into the current model, and then input to the voltage model through a PI controller. The PI controller iteratively adjusts the flux linkage weights in the current model and the voltage model according to the output of the voltage model to determine the rotor position observation information for which the speed can be obtained. The rotor position angle is weighted by flux linkage through PI control, thereby achieving smooth change of motor speed. This solves the problem that the speed cannot be smoothly switched in existing sensorless systems, which easily leads to speed jumps and poses a high safety risk. Attached Figure Description

[0035] Figure 1 These are schematic diagrams of system modules for embodiments one and two of the motor speed switching system and method applied to a sensorless electric drive system according to the present invention;

[0036] Figure 2 This is a schematic diagram of the control logic of the hybrid flux observation model in Embodiments 1 and 2 of the motor speed switching system and method applied to a sensorless electric drive system according to the present invention;

[0037] Figure 3 This is a schematic diagram of the control logic of the current model and voltage model in Embodiments 1 and 2 of the motor speed switching system and method applied to a sensorless electric drive system according to the present invention;

[0038] Figure 4 The following are flowcharts of embodiments one and two of the motor speed switching system and method applied to a sensorless electric drive system according to the present invention.

[0039] Figure label:

[0040] 1-First processing module; 11-Hybrid flux linkage observation model; 111-Current model; 112-PI controller; 113-Voltage model; 2-Acquisition module; 3-Conversion module; -Second processing module. Detailed Implementation

[0041] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0042] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0043] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0044] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0045] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0046] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0047] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0048] Example 1: This embodiment provides a motor speed switching system for sensorless electric drive systems. It incorporates a motor speed control algorithm for sensorless scenarios, specifically integrating a high-frequency injection strategy for low speeds and a back-EMF observation strategy for medium and high speeds. A PI controller is used to dynamically allocate the contribution of the rotor position (observation values) obtained from these two strategies, achieving smooth switching of motor speed across the entire speed domain. For details, please refer to [link to documentation]. Figures 1-3 The system includes:

[0049] The acquisition module acquires rotor position estimation information obtained after injecting a high-frequency voltage signal into the motor. ;

[0050] The first processing module establishes a hybrid flux observation model, including a current model, a PI controller, and a voltage model.

[0051] The current model calculates the first flux linkage information based on the current signal and the rotor position estimation information. ;

[0052] The voltage model receives the first flux linkage information via the output of a PI controller and calculates the second flux linkage information using the back electromotive force integral. The third magnetic flux information is output through integral fusion. ;

[0053] The PI controller is connected to the current model and the voltage model. It processes the output of the current model and inputs it to the voltage model, while simultaneously receiving the third flux linkage information fed back from the voltage model. To dynamically allocate third magnet link information China's first magnetic link information Information with the second magnetic link The corresponding weights are used to iteratively adjust the third magnetic flux information. The rotor position observation information is obtained to smoothly switch the rotational speed.

[0054] In this embodiment, The rotor position estimation information is obtained using a high-frequency signal injection method, which is a widely used and existing solution for sensorless rotor position observation at low speeds. This method requires this value as input to the fused flux linkage observation model, and therefore can be directly obtained based on the existing drive system. It is also possible to deploy independent modules to calculate Specifically, as a preferred implementation, it also includes a second processing module for calculating rotor position estimation information after injecting a high-frequency voltage signal into the motor. It is understandable that the injected high-frequency current signal (typically 500Hz~2kHz) will interact with the motor's salient pole effect (magnetic circuit asymmetry, i.e.,...) The interaction between the two signals generates a response voltage or current containing rotor position information. By demodulating these response signals, the position information can be extracted. A high-frequency voltage signal is then injected to obtain the q-axis high-frequency current component. This current component contains angular error information, which can be eliminated through PI control, filtering, and other operations to extract the position information from this current component. .

[0055] In this embodiment, a hybrid flux linkage observation model is established under the first processing module, including a current model, a PI controller, and a voltage model. The current model is based on the current-flux linkage relationship and is based on the input dq-axis current. Output flux linkage (first flux linkage information), determine the amplitude and shape of the flux linkage based on the dq-axis current, and utilize... The spatial phase and orientation accuracy of the flux linkage are determined. The voltage model derives the flux linkage from the back electromotive force integral based on the three-phase voltage and three-phase current, which is the second flux linkage information obtained in this embodiment. It can be understood that the current model relies on the current integral and the current loop bandwidth, and performs better at low speeds. The voltage model relies on the back electromotive force, but its signal-to-noise ratio is high, so it performs better at medium and high speeds. Therefore, in this embodiment, the flux linkage is weighted based on the two models, and the weights are dynamically allocated through a PI controller. The core function of the PI controller is to eliminate system errors by dynamically adjusting the output, and to fuse the flux linkage integrals of the two models to output the third flux linkage information, thereby adjusting according to the feedback of the third flux linkage information (output).

[0056] Specifically, a specific structure for a hybrid magnetic flux observation model is provided:

[0057] In the current model, the current along the dq axis is... As input, the dq-axis current first passes through Perform the inverse transformation of the rotation coordinates, from the dq axis ( , Transformed into αβ axis ( , ), calculate flux linkage: ; ; For permanent magnet flux; then through Perform a rotational coordinate transformation and output the first magnetic flux information;

[0058] The current model output is connected to a PI controller. The first flux linkage information serves as one input to the PI controller, and the third flux linkage information serves as the other input. This information is then processed through the transfer function in the PI controller. For proportional gain, For integral gain, through The integral calculation is input into the voltage model;

[0059] In the voltage model, three-phase voltage and three-phase current are used as inputs, through Calculate the back electromotive force. A vector in the stationary coordinate system αβ. The stator resistance is integrated to obtain the flux linkage, i.e., the second flux linkage information. In the voltage model, the first flux linkage information and the second flux linkage information are integrated and fused to output the third flux linkage information. The third flux linkage information is fed back to the input of the PI controller. The PI controller assigns weights and iteratively updates the output, i.e., updates the third flux linkage information.

[0060] Based on the above, in this embodiment, the weight allocation is based on the flux linkage calculated by the current model using current and the flux linkage calculated by the voltage model using electromotive force. Then, the components are integrated and fused to output the third flux linkage information. The third flux linkage information can reflect the rotor position observation information through PI control (from which the motor speed can be obtained). PI regulation is a dynamic iterative regulation process that can maintain speed stability. By eliminating speed deviation through the integral term, speed regulation and speed stability can be balanced, thereby achieving smooth speed conversion.

[0061] It is worth noting that the purpose of the hybrid flux linkage observation model described above in this embodiment is to observe the current rotor position through an algorithm in a scenario without a speed sensor. Its output flux linkage information can be used to obtain the rotor position through function transformation. Therefore, the system may also include a transformation module that, based on the third flux linkage information, uses an arctangent function (… The rotor position observation information is obtained by calculation, that is ;in , Obtained based on third magnet link information.

[0062] Based on the above, the motor speed switching system in this embodiment establishes a hybrid flux linkage observation model to observe the rotor position in the absence of a speed sensor, thereby obtaining the rotational speed and performing switching at all speeds. Specifically, this is achieved by injecting a high-frequency voltage signal to obtain the rotational speed. As input to the current model, the magnetic flux corresponding to the current model and voltage model is dynamically adjusted by the PI controller. Weighted control is performed on the magnetic flux angle, thereby achieving weighted control of the rotor angle calculated by different schemes at low speed and high speed through the PI controller, thus realizing smooth switching of motor speed.

[0063] Understandably, the above modules can also be integrated with and / or connected to other modules / units / devices, or equipped with other general control algorithms / control programs to integrate other control functions, so as to realize the application of the drive system in different scenarios and improve control accuracy.

[0064] Example 2: This example also discloses a method for switching motor speeds in a sensorless electric drive system, which applies the system described in Example 1 above. For details, please refer to... Figures 1-4 This includes the following steps:

[0065] S10: Obtain rotor position estimation information calculated by injecting a high-frequency voltage signal into the motor. ;

[0066] Specifically, a high-frequency voltage signal is injected into the motor to obtain the high-frequency current component of the motor response; based on this high-frequency current component, rotor position estimation information is calculated through extraction using a bandpass filter and PI control. As an example, the aforementioned high-frequency voltage signal can be represented as: The above high-frequency current components can be expressed as: Multiply by the original high-frequency signal Thus, we obtain: Then, based on low-pass filtering, high-frequency components are filtered out. Retain the DC error signal; then, through PI control, adjust the error signal to 0, and the output can be obtained. Its control logic is consistent with existing common high-frequency signal methods. In this embodiment, the output rotor position estimation information is applied. The dwarf is injected into the following hybrid flux observation model to achieve smooth switching of rotational speed by controlling the weighted angle through PI regulation.

[0067] S20: Establish a hybrid flux observation model, including a current model, a PI controller, and a voltage model;

[0068] The first flux linkage information is calculated using a current model based on the current signal and the rotor position estimation information. ;

[0069] The first flux linkage information is output to the voltage model via a PI controller, and the second flux linkage information is calculated within the voltage model using back electromotive force integration. The third magnetic flux information is output through integral fusion;

[0070] Simultaneously, the third flux linkage information is fed back to the PI controller, enabling the PI controller to dynamically allocate the weights corresponding to the first flux linkage information and the second flux linkage information in the fused flux linkage information, thereby iteratively adjusting the third flux linkage information to obtain rotor position observation information based on the third flux linkage information and perform smooth switching of speed (from low speed to high speed or from high speed to low speed).

[0071] The aforementioned smooth switching refers to the absence of sudden speed changes. The speed is dynamically and gradually updated as the speed changes. In this application, the weight allocation is gradually adjusted through PI control, that is, the contributions of the current model and the voltage model change dynamically to achieve smooth speed switching.

[0072] It is also worth noting that the weight allocation of the flux linkage (intermediate parameters of the model) controlled by PI in this application is significantly different from the integration of speed weighting under multiple observation strategies in the prior art. Moreover, it does not require speed conversion, resulting in higher control accuracy, smoother switching effect, and higher efficiency.

[0073] Specifically, the system provided in Embodiment 1 above (such as...) can be used as a reference. Figure 2 and 3 Example:

[0074] The first function is established based on the difference between the first and third magnetic flux linkage information, output by a PI controller; the first function can be expressed as: ;

[0075] The second function is established by integrating the output of the PI controller with the back electromotive force to output the third flux linkage information; the second function can be expressed as: ;in ;

[0076] The third function is established by outputting the second flux linkage information based on the back electromotive force integral calculation; the third function is expressed as: ;

[0077] The allocation function is obtained by solving the first, second, and third functions described above: ;in To integrate magnet link information; This is the first magnet link information; This is the second magnetic link information; , These are the preset parameters for the PI controller.

[0078] Specifically, the PI controller dynamically allocates the weights corresponding to the first and second magnetic flux information in the fused magnetic flux information, and controls the system according to the allocation function described above.

[0079] Based on the description in Embodiment 1 above, it is understandable that the rotor position is observed based on the output flux linkage. Therefore, it is necessary to calculate the rotor position observation information using the arctangent function based on the third flux linkage information, i.e. As can be understood, the first and second flux linkage information mentioned above can both be used to calculate the observed rotor position using the arctangent function. Therefore, dynamic weighted control of the rotor position can be achieved through PI control. Specifically, it can be expressed as:

[0080] ; For rotor position observation information, The rotor position observations calculated using the current model; The rotor position observations are calculated using the back electromotive force method from the voltage model.

[0081] Based on the above, this embodiment uses a PI controller to obtain the rotor position observation value, i.e., the rotor position estimation information, by injecting a high-frequency signal. And the rotor position observations calculated by the voltage model using the back electromotive force method Angle weighting is performed; by weighting the intermediate parameters (each flux linkage) in the hybrid flux linkage observation model, the angle is weighted to determine the final rotor position observation information corresponding to the motor speed, so as to smoothly switch the motor speed through PI control.

[0082] In this embodiment, adjusting the amplitude of the high-frequency voltage signal to control the start and stop of the hybrid flux linkage observation model, i.e., the on and off operations (speed switching), can be accomplished by adjusting the amplitude of the injection signal relative to the speed. Furthermore, the frequencies of the aforementioned flux linkages have a certain linear relationship with the rotational speed, and the relationship between the alternating frequency of the flux linkages and the rotor mechanical speed is as follows: ; The number of electrode pairs is used to determine the iterative control process of the PI controller for adjusting the speed change, so that the motor can smoothly switch to a certain speed.

[0083] In this embodiment, smooth switching of motor speed can be achieved through PI control. As can be understood, as mentioned above, the rotor position estimation information obtained by injecting a high-frequency signal at low speed... The accuracy is relatively high, and the rotor position observations calculated by the voltage model through back electromotive force at medium altitudes are... The accuracy is high. Therefore, when the motor is at a predetermined low speed, the PI controller adjusts the weight corresponding to the first flux linkage information to 1 and the weight corresponding to the second flux linkage information to 0. When the motor is at a predetermined high speed, the PI controller adjusts the weight corresponding to the second flux linkage information to 1 and the weight corresponding to the first flux linkage information to 0. When the motor is in the transition from low speed to high speed, the PI controller dynamically allocates the weights corresponding to the first flux linkage information and the second flux linkage information in the fused flux linkage information.

[0084] It is understood that the above low speed and high speed are predetermined values. For example, the low speed can be set to about 10% of the maximum speed, that is, 0 to 10% of the maximum speed is low speed, and about 15% of the maximum speed is medium and high speed. Then, anything exceeding 15% of the maximum speed is high speed. Thus, PI control is used between 10% and 15% of the speed to achieve smooth switching. Other values ​​can be based on the preset weights mentioned above.

[0085] Based on the above, the motor speed switching method for a sensorless electric drive system provided in this embodiment, and the system provided in Embodiment 1 above, utilize the rotor position estimation information obtained after injecting a high-frequency signal into the motor. The current is injected into the current model and then input to the voltage model through a PI controller. The PI controller iteratively adjusts the contribution of the intermediate parameters (magnetic flux) of the current model and the voltage model based on the output of the voltage model. That is, the PI control weighting based on the magnetic flux realizes the weighting of the rotor position observation value, thereby determining the final rotor position observation information, which corresponds to the speed. The PI control realizes the angle weighting, thereby realizing the smooth change of the motor speed.

[0086] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A motor speed switching system for use in a sensorless electric drive system, characterized in that, include: The acquisition module acquires rotor position estimation information obtained after injecting a high-frequency voltage signal into the motor; The first processing module establishes a hybrid flux observation model, including a current model, a PI controller, and a voltage model. The current model calculates the first flux linkage information based on the current signal and the rotor position estimation information. The voltage model receives the first flux linkage information through the output of the PI controller, calculates the second flux linkage information by integrating the back electromotive force, and outputs the third flux linkage information by integrating and fusing the components. The PI controller is connected to the current model and the voltage model. It processes the output of the current model and inputs it to the voltage model. At the same time, it receives the third flux linkage information fed back by the voltage model to dynamically allocate the weights corresponding to the first flux linkage information and the second flux linkage information in the third flux linkage information. This allows for iterative adjustment of the third flux linkage information and the acquisition of rotor position observation information for smooth speed switching.

2. The motor speed switching system according to claim 1, characterized in that, include: The conversion module calculates the rotor position observation information using the arctangent function based on the third flux linkage information.

3. The motor speed switching system according to claim 1, characterized in that, include: The second processing module is used to inject a high-frequency voltage signal into the motor and then calculate the rotor position estimation information.

4. A method for switching motor speed in a sensorless electric drive system, characterized in that, include: Obtain rotor position estimation information calculated by injecting a high-frequency voltage signal into the motor; A hybrid flux observation model is established, including a current model, a PI controller, and a voltage model; The first flux linkage information is calculated using a current model based on the current signal and the rotor position estimation information. The first flux linkage information is output to the voltage model through a PI controller. The second flux linkage information is calculated using the back electromotive force integration within the voltage model. The third flux linkage information is output through integration and fusion. Simultaneously, the third flux linkage information is fed back to the PI controller, enabling the PI controller to dynamically allocate the weights corresponding to the first and second flux linkage information in the fused flux linkage information, thereby iteratively adjusting the third flux linkage information to obtain rotor position observation information based on the third flux linkage information for smooth speed switching.

5. The motor speed switching method according to claim 4, characterized in that: The PI controller dynamically allocates the weights corresponding to the first and second flux linkage information in the fused flux linkage information, and controls it according to the following allocation function: ;in To integrate magnet link information; This is the first magnet link information; This is the second magnetic link information; , These are the preset parameters for the PI controller.

6. The motor speed switching method according to claim 4, characterized in that: The first function is established by outputting the PI controller based on the difference between the first flux linkage information and the third flux linkage information. The second function is established by performing an integral operation based on the sum of the PI controller output and the back electromotive force to output the third flux linkage information. A third function is established by outputting the second flux linkage information based on the back electromotive force integral calculation; The allocation function is obtained by solving the first function, the second function, and the third function.

7. The motor speed switching method according to claim 4, characterized in that, include: A high-frequency voltage signal is injected into the motor to obtain the high-frequency current component of the motor response; The rotor position estimation information is calculated based on the high-frequency current component extracted by a bandpass filter and PI control.

8. The motor speed switching method according to claim 7, characterized in that: The amplitude of the high-frequency voltage signal is adjusted to control the start and stop of the hybrid magnetic flux observation model.

9. The motor speed switching method according to claim 4, characterized in that, include: When the motor is at a predetermined low speed, the PI controller adjusts the weight corresponding to the first flux linkage information to 1 and the weight corresponding to the second flux linkage information to 0. When the motor is at the predetermined high speed, the PI controller adjusts the weight corresponding to the second flux linkage information to 1 and the weight corresponding to the first flux linkage information to 0. When the motor is in the low-speed to high-speed transition, the PI controller dynamically allocates the weights corresponding to the first flux linkage information and the second flux linkage information in the fused flux linkage information.

10. The motor speed switching method according to claim 4, characterized in that: Based on the third flux linkage information, the rotor position observation information is calculated using the arctangent function.

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