Method and device for controlling a synchronous machine

Abstract

The application discloses a synchronous motor control method and device, the method comprises the following steps: firstly, determining the rotor position preliminary value and the rotor speed preliminary value of the synchronous motor based on the flux linkage observer; then, determining the rotor position correction value and the rotor speed correction value based on the load torque of the synchronous motor; then, obtaining the rotor position final value and the rotor speed final value by correcting the rotor position preliminary value and the rotor speed preliminary value according to the rotor position correction value and the rotor speed correction value; finally, controlling the starting synchronous motor based on the rotor position final value and the rotor speed final value, which can more accurately and quickly control the starting of the synchronous motor without the separate initial position identification process.

Description

Technical Field

[0001] This invention belongs to the field of synchronous motor technology, and specifically relates to a synchronous motor control method and device. Background Technology

[0002] Conventional synchronous motors typically use flux linkage observers to estimate the rotor position and speed during startup, thereby controlling the motor's start-up. However, this method is prone to converging to incorrect convergence points when the initial position of the synchronous motor is unknown, leading to stalling during load startup. Current solutions involve using a separate initial position identification stage to obtain the initial position of the synchronous motor offline before each startup. However, the initial position identification method for synchronous motors places high demands on the sampling accuracy of the motor control system, and the identification process is cumbersome.

[0003] Therefore, how to more accurately and quickly control the start-up of synchronous motors is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems in the prior art where the use of a flux linkage observer to control the start of a synchronous motor is prone to stalling faults, or where the need for a position observer to identify the initial position of the motor causes cumbersome control.

[0005] To achieve the above-mentioned technical objectives, in one aspect, the present invention provides a synchronous motor control method, the method comprising:

[0006] The preliminary values ​​of the rotor position and rotor speed of the synchronous motor were determined based on the flux linkage observer.

[0007] The rotor position correction value and rotor speed correction value are determined based on the load torque of the synchronous motor.

[0008] After correcting the initial values ​​of rotor position and rotor speed based on the rotor position correction value and rotor speed correction value, the final values ​​of rotor position and rotor speed are obtained.

[0009] The synchronous motor is started based on the final values ​​of the rotor position and rotor speed.

[0010] Furthermore, the determination of the preliminary rotor position and preliminary rotor speed of the synchronous motor based on the flux linkage observer specifically includes:

[0011] The stator flux linkage vector estimate in the stationary coordinate system was determined using a flux linkage observer. Components and Quantity;

[0012] Based on the estimated value of the stator flux linkage vector in the stationary coordinate system Components and The components determine the estimated value of the rotor flux vector in the stationary coordinate system. Components and Quantity;

[0013] Based on the rotor flux vector estimate in the stationary coordinate system Components and The components determine the initial values ​​of the rotor position and rotor speed.

[0014] Furthermore, the magnetic flux observer is specifically shown in the following formula:

[0015] ,

[0016] In the formula, The estimated value of the stator flux linkage vector in the stationary coordinate system Quantity, The estimated value of the stator flux linkage vector in the stationary coordinate system Quantity, The stator voltage vector in the stationary coordinate system Quantity, The stator voltage vector in the stationary coordinate system Quantity, For stator resistance, The stator current vector in the stationary coordinate system Quantity, The stator current vector in the stationary coordinate system Quantity, The correction terms for the flux linkage observer in the stationary coordinate system Quantity, The correction terms for the flux linkage observer in the stationary coordinate system Quantity, d For differential operators, t For time.

[0017] Furthermore, the preliminary values ​​of the rotor position and rotor speed are determined using the following formulas:

[0018] ,

[0019] In the formula, This is the initial value of the rotor position. This is the initial value of the rotor speed. It is the arctangent function. The rotor flux linkage vector estimate in the stationary coordinate system Quantity, The rotor flux linkage vector in the stationary coordinate system Quantity, d For differential operators, t For time.

[0020] Furthermore, the rotor position correction value and rotor speed correction value are determined based on the load torque of the synchronous motor, specifically by using the following formula:

[0021] ,

[0022] In the formula, This is the rotor speed correction value. This is the rotor position correction value. For symbolic functions, For electromagnetic torque, To estimate the rotor speed considering load torque, For load torque, This is the target speed of the synchronous motor.

[0023] Furthermore, the rotor speed estimate considering load torque is specifically determined by the following formula:

[0024] ,

[0025] In the formula, Gain for estimating load torque. For the system's mechanical inertia, This is the initial value of the rotor speed. d For differential operators, t For time, This represents the load torque.

[0026] Furthermore, the load torque is specifically determined by the following formula:

[0027] ,

[0028] In the formula, Gain for load torque estimation.

[0029] Furthermore, the final values ​​of the rotor position and rotor speed are obtained using the following formulas:

[0030] ,

[0031] In the formula, This is the final value of the rotor position. This is the final value of the rotor speed. This is the initial value of the rotor position. This is the rotor position correction value. To estimate the rotor speed considering load torque, This is the rotor speed correction value.

[0032] On the other hand, this application also provides a synchronous motor control device, the device comprising:

[0033] The flux linkage observer module is used to determine the preliminary values ​​of the rotor position and rotor speed of the synchronous motor.

[0034] The correction module is used to determine the rotor position correction value and the rotor speed correction value based on the load torque of the synchronous motor.

[0035] The determining module is used to correct the preliminary values ​​of rotor position and rotor speed based on the rotor position correction value and rotor speed correction value to obtain the final values ​​of rotor position and rotor speed.

[0036] The control module is used to control the start of the synchronous motor based on the final values ​​of the rotor position and rotor speed.

[0037] The present invention provides a synchronous motor control method and apparatus. Compared with the prior art, this method first determines the preliminary values ​​of the rotor position and rotor speed of the synchronous motor based on a flux linkage observer; then, it determines the rotor position correction value and rotor speed correction value based on the load torque of the synchronous motor; next, it corrects the preliminary values ​​of the rotor position and rotor speed according to the rotor position correction value and rotor speed correction value to obtain the final values ​​of the rotor position and rotor speed; finally, it controls the start of the synchronous motor based on the final values ​​of the rotor position and rotor speed, which can more accurately and quickly control the start of the synchronous motor without the need for a separate initial position identification process. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 The diagram shown is a schematic flowchart of the synchronous motor control method provided in the embodiments of this specification;

[0040] Figure 2 The diagram shown is a structural schematic of the synchronous motor control device provided in the embodiments of this specification.

[0041] Figure 3 The diagram shows the magnetic flux linkage of a two-phase rotor at different initial positions. Detailed Implementation

[0042] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] like Figure 1 The diagram shown is a flowchart illustrating the synchronous motor control method provided in the embodiments of this specification. Although this specification provides the method operation steps or device structure shown in the following embodiments or figures, based on convention or without creative effort, the method or device may include more or fewer operation steps or module units after partial merging. In steps or structures where there is no necessary causal relationship in logic, the execution order of these steps or the module structure of the device are not limited to the execution order or module structure shown in the embodiments or figures of this specification. When the method or module structure is applied in actual devices, servers, or terminal products, it can be executed sequentially or in parallel according to the method or module structure shown in the embodiments or figures (e.g., in a parallel processor or multi-threaded processing environment, or even in a distributed processing or server cluster implementation environment).

[0044] The synchronous motor control method provided in the embodiments of this specification is as follows: Figure 1 As shown, the method specifically includes the following steps:

[0045] Step S101: Determine the preliminary values ​​of the rotor position and rotor speed of the synchronous motor based on the flux linkage observer.

[0046] In this embodiment of the application, the determination of the preliminary values ​​of the rotor position and rotor speed of the synchronous motor based on the flux linkage observer specifically includes:

[0047] The stator flux linkage vector estimate in the stationary coordinate system was determined using a flux linkage observer. Components and Quantity;

[0048] Based on the estimated value of the stator flux linkage vector in the stationary coordinate system Components and The components determine the estimated value of the rotor flux vector in the stationary coordinate system. Components and Quantity;

[0049] Based on the rotor flux vector estimate in the stationary coordinate system Components and The components determine the initial values ​​of the rotor position and rotor speed.

[0050] Specifically, the stator flux linkage equation of the synchronous motor in the two-phase stationary coordinate system is as follows:

[0051] ,

[0052] In the formula, The stator flux linkage vector in the stationary coordinate system Quantity, The stator flux linkage vector in the stationary coordinate system Quantity.

[0053] The stator flux linkage equation of a synchronous motor in a two-phase stationary coordinate system can also be described as a function of the rotor position, as shown below:

[0054] ,

[0055] In the formula, To consider the stator flux linkage vector in the stationary coordinate system with respect to the rotor position Quantity, To consider the stator flux linkage vector in the stationary coordinate system with respect to the rotor position Quantity, This represents the rotor flux linkage amplitude. L It is the stator inductance.

[0056] Based on the stator flux linkage equations and the function relating to rotor position, a flux linkage observer based on a hybrid model can be constructed, as shown in the following equation:

[0057] ,

[0058] In the formula, The estimated value of the stator flux linkage vector in the stationary coordinate system Quantity, The estimated value of the stator flux linkage vector in the stationary coordinate system Quantity, The stator voltage vector in the stationary coordinate system Quantity, The stator voltage vector in the stationary coordinate system Quantity, For stator resistance, The stator current vector in the stationary coordinate system Quantity, The stator current vector in the stationary coordinate system Quantity, The correction terms for the flux linkage observer in the stationary coordinate system Quantity, The correction terms for the flux linkage observer in the stationary coordinate system Quantity, d For differential operators, t For time.

[0059] in, and It can be determined using the following formula:

[0060] ,

[0061] In the formula, This refers to the proportional gain in the correction term of the flux linkage observer. This is the integral gain in the correction term of the flux linkage observer.

[0062] Based on the above, the estimated value of the stator flux linkage vector in the stationary coordinate system is determined. Components and The components can be determined by the following formula for the estimated value of the rotor flux vector in the stationary coordinate system. Components and Quantity;

[0063] ,

[0064] Then, the preliminary values ​​of the rotor position and rotor speed are determined using the following formulas:

[0065] ,

[0066] In the formula, This is the initial value of the rotor position. This is the initial value of the rotor speed. It is the arctangent function. The rotor flux linkage vector estimate in the stationary coordinate system Quantity, The rotor flux linkage vector in the stationary coordinate system Quantity, d For differential operators, t For time, through and The positive and negative signs of each function can be used to calculate the arctangent function in the four quadrants.

[0067] Step S102: Determine the rotor position correction value and rotor speed correction value based on the load torque of the synchronous motor.

[0068] Specifically, such as Figure 3 The diagram shows the magnetic flux linkage of a two-phase rotor at different initial positions. Figure 3The diagrams, from top to bottom, show the rotor flux linkage under the following conditions: forward rotation with an initial position of 0, reverse rotation with an initial position of 0, and reverse rotation with an initial position of π. Figure 3 It can be seen that the rotor flux vector estimated by this type of flux observer has two convergence points, among which, Figure 3 The dashed lines in the diagram indicate the initial position as π, i.e., the initial state of the rotor flux vector. The initial state of the rotor flux vector is the same in both the forward rotation with an initial position of 0 and the reverse rotation with an initial position of π. Figure 3 The initial state of the rotor flux linkage under the condition of forward rotation and initial position 0 is the same as the initial state of the rotor flux linkage under the condition of reverse rotation and initial position π. This will cause the flux linkage observer to eventually converge to one of the two convergence points when the initial position is inaccurate. However, only one of the two convergence points is the correct convergence point. The other convergence point will cause the synchronous motor to fail to operate normally in the expected direction of rotation, resulting in a stall.

[0069] This application extracts load torque information from the motor speed estimated by the flux linkage observer. By comprehensively judging the electric motor generation state corresponding to the load torque and the electric motor generation state corresponding to the electromagnetic torque, a secondary correction is performed on the estimated motor position and speed under the incorrect convergence point condition of the flux linkage observer. This ensures that the flux linkage observer can converge to the correct convergence point under any initial position error condition, thereby ensuring that the synchronous motor can run directly under the control of this new sensorless method without the need for a separate initial position identification stage.

[0070] First, the electromagnetic torque equation of the synchronous motor is determined, as shown below:

[0071] ,

[0072] In the formula, This represents the number of pole pairs of the motor.

[0073] Based on the electromagnetic torque equation, the expression for the load torque of the synchronous motor can be obtained as follows:

[0074] ,

[0075] In the formula, and All are load torque estimation gains.

[0076] In this embodiment of the application, the determination of the rotor position correction value and the rotor speed correction value based on the load torque of the synchronous motor is specifically performed using the following formula:

[0077] ,

[0078] In the formula, This is the rotor speed correction value. This is the rotor position correction value. For symbolic functions, with For example, when When greater than or equal to 0, =1, otherwise -1, For electromagnetic torque, To estimate the rotor speed considering load torque, For load torque, This is the target speed of the synchronous motor.

[0079] The rotor speed estimate considering load torque is determined using the following formula:

[0080] ,

[0081] In the formula, Gain for estimating load torque. For the system's mechanical inertia, This is the initial value of the rotor speed. d For differential operators, t For time, This represents the load torque.

[0082] The load torque is specifically determined by the following formula:

[0083] ,

[0084] In the formula, Gain for load torque estimation.

[0085] Step S103: Correct the initial values ​​of rotor position and rotor speed according to the rotor position correction value and rotor speed correction value to obtain the final values ​​of rotor position and rotor speed.

[0086] In this embodiment, the final values ​​of the rotor position and rotor speed are obtained using the following formulas:

[0087] ,

[0088] In the formula, This is the final value of the rotor position. This is the final value of the rotor speed. This is the initial value of the rotor position. This is the rotor position correction value. To estimate the rotor speed considering load torque, This is the rotor speed correction value.

[0089] Step S104: Control the start of the synchronous motor based on the final value of the rotor position and the final value of the rotor speed.

[0090] Specifically, after determining the final values ​​of the rotor position and rotor speed, the synchronous motor can be controlled by the motor control system without the need for separate initial position identification.

[0091] Based on the above-described synchronous motor control method, one or more embodiments of this specification also provide a synchronous motor control platform or terminal. This platform or terminal may include devices, software, modules, plug-ins, servers, clients, etc., using the methods described in the embodiments of this specification, combined with necessary hardware implementation devices. Based on the same innovative concept, the systems in one or more embodiments provided in this specification are as described in the following embodiments. Since the implementation schemes and methods for solving the system problem are similar, the specific system implementation in the embodiments of this specification can refer to the implementation of the aforementioned methods. Repeated descriptions will not be repeated. The terms "unit" or "module" used below can refer to a combination of software and / or hardware that achieves a predetermined function. Although the systems described in the following embodiments are preferably implemented in software, hardware implementation, and a combination of software and hardware, are also possible and contemplated.

[0092] Specifically, Figure 2 This is a schematic diagram of the module structure of one embodiment of the synchronous motor control device provided in this specification, as shown below. Figure 2 As shown, the synchronous motor control device provided in this specification includes:

[0093] The flux linkage observer module 201 is used to determine the preliminary values ​​of the rotor position and rotor speed of the synchronous motor.

[0094] The correction module 202 is used to determine the rotor position correction value and the rotor speed correction value based on the load torque of the synchronous motor.

[0095] The determining module 203 is used to correct the preliminary values ​​of rotor position and rotor speed based on the rotor position correction value and rotor speed correction value to obtain the final values ​​of rotor position and rotor speed.

[0096] The control module 204 is used to control the start of the synchronous motor based on the final value of the rotor position and the final value of the rotor speed.

[0097] It should be noted that the system described above may include other implementation methods based on the description of the corresponding method embodiments. The specific implementation methods can be referred to the description of the corresponding method embodiments above, and will not be elaborated here.

[0098] This application also provides an electronic device, including:

[0099] processor;

[0100] Memory used to store the processor's executable instructions;

[0101] The processor is configured to perform the methods provided in the embodiments described above.

[0102] The electronic device provided in this application embodiment stores executable instructions of the processor in a memory. When the processor executes the executable instructions, it can first determine the preliminary values ​​of the rotor position and rotor speed of the synchronous motor based on the flux linkage observer; then, it determines the rotor position correction value and rotor speed correction value based on the load torque of the synchronous motor; next, it corrects the preliminary values ​​of the rotor position and rotor speed according to the rotor position correction value and rotor speed correction value to obtain the final values ​​of the rotor position and rotor speed; finally, it controls the start of the synchronous motor based on the final values ​​of the rotor position and rotor speed, which can more accurately and quickly control the start of the synchronous motor without performing a separate initial position identification process.

[0103] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0104] The methods or apparatus described in the embodiments provided in this specification can implement business logic through a computer program and record it on a storage medium. The storage medium can be read and executed by a computer to achieve the effects of the solutions described in the embodiments of this specification, such as:

[0105] The preliminary values ​​of the rotor position and rotor speed of the synchronous motor were determined based on the flux linkage observer.

[0106] The rotor position correction value and rotor speed correction value are determined based on the load torque of the synchronous motor.

[0107] After correcting the initial values ​​of rotor position and rotor speed based on the rotor position correction value and rotor speed correction value, the final values ​​of rotor position and rotor speed are obtained.

[0108] The synchronous motor is started based on the final values ​​of the rotor position and rotor speed.

[0109] The storage medium can include physical devices for storing information, typically digitizing the information and then storing it using electrical, magnetic, or optical methods. The storage medium can include: devices that store information using electrical energy, such as various types of memory, like RAM and ROM; devices that store information using magnetic energy, such as hard disks, floppy disks, magnetic tapes, magnetic core memory, bubble memory, and USB flash drives; and devices that store information using optical methods, such as CDs or DVDs. Of course, there are other readable storage media, such as quantum memories and graphene memories.

[0110] The embodiments in this specification are not limited to conforming to industry communication standards, standard computer resource data update and data storage rules, or the situations described in one or more embodiments of this specification. Slightly modified implementations based on certain industry standards or custom methods or embodiments can also achieve the same, equivalent, or similar, or predictable, implementation effects as described above. Embodiments that utilize these modified or modified methods for data acquisition, storage, judgment, and processing still fall within the scope of optional implementations of the embodiments in this specification.

[0111] The controller can be implemented in any suitable manner. For example, it can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers. Examples of controllers include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicon Labs C8051F320. A memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art will also recognize that, in addition to implementing the controller in purely computer-readable program code form, the same functionality can be achieved by logically programming the method steps to make the controller take the form of logic gates, switches, ASICs, programmable logic controllers, and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the means included therein for implementing various functions can also be considered as structures within the hardware component. Alternatively, the means for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0112] The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or plug-ins may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, indirect coupling or communication connection between devices or units, and may be electrical, mechanical, or other forms.

[0113] These computer program instructions can also be loaded onto a computer or other programmable resource data updating device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable device for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0114] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, system embodiments are basically similar to method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. In the description of this specification, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this specification. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0115] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A synchronous motor control method, characterized in that, The method includes: The preliminary values ​​of the rotor position and rotor speed of the synchronous motor were determined based on the flux linkage observer. The rotor position correction value and rotor speed correction value are determined based on the load torque of the synchronous motor. The rotor speed correction value is obtained according to the sign function to correct the preliminary rotor position and rotor speed values ​​estimated under the fault convergence point condition of the flux linkage observer. After correcting the initial values ​​of rotor position and rotor speed based on the rotor position correction value and rotor speed correction value, the final values ​​of rotor position and rotor speed are obtained. The synchronous motor is started based on the final values ​​of the rotor position and rotor speed.

2. The synchronous motor control method as described in claim 1, characterized in that, The determination of the preliminary rotor position and preliminary rotor speed of the synchronous motor based on the flux linkage observer specifically includes: The stator flux linkage vector estimate in the stationary coordinate system was determined using a flux linkage observer. Components and Quantity; Based on the estimated value of the stator flux linkage vector in the stationary coordinate system Components and The components determine the estimated value of the rotor flux vector in the stationary coordinate system. Components and Quantity; Based on the rotor flux linkage vector estimate in the stationary coordinate system Components and The components determine the initial values ​​of the rotor position and rotor speed.

3. The synchronous motor control method as described in claim 2, characterized in that, The magnetic flux observer is specifically shown in the following formula: ； In the formula, The estimated value of the stator flux linkage vector in the stationary coordinate system Quantity, The estimated value of the stator flux linkage vector in the stationary coordinate system Quantity, The stator voltage vector in the stationary coordinate system Quantity, The stator voltage vector in the stationary coordinate system Quantity, For stator resistance, The stator current vector in the stationary coordinate system Quantity, The stator current vector in the stationary coordinate system Quantity, The correction terms for the flux linkage observer in the stationary coordinate system Quantity, The correction terms for the flux linkage observer in the stationary coordinate system Quantity, For differential operators, For time.

4. The synchronous motor control method as described in claim 2, characterized in that, Specifically, the initial values ​​of rotor position and rotor speed are determined using the following formulas: ； In the formula, This is the initial value of the rotor position. This is the initial value of the rotor speed. It is the arctangent function. The rotor flux linkage vector estimate in the stationary coordinate system Quantity, The rotor flux linkage vector in the stationary coordinate system Quantity, For differential operators, For time.

5. The synchronous motor control method as described in claim 1, characterized in that, The rotor position correction value and rotor speed correction value are determined based on the load torque of the synchronous motor, specifically using the following formula: ； In the formula, This is the rotor speed correction value. This is the rotor position correction value. For symbolic functions, For electromagnetic torque, To estimate the rotor speed considering load torque, For load torque, This is the target speed of the synchronous motor.

6. The synchronous motor control method as described in claim 5, characterized in that, The rotor speed estimate considering load torque is determined using the following formula: ； In the formula, Gain for estimating load torque. For the system's mechanical inertia, This is the initial value of the rotor speed. For differential operators, For time, This represents the load torque.

7. The synchronous motor control method according to any one of claims 5-6, characterized in that, The load torque is specifically determined by the following formula: ； In the formula, Gain for estimating load torque. This is the initial value of the rotor speed.

8. The synchronous motor control method as described in claim 1, characterized in that, The final values ​​of rotor position and rotor speed are obtained using the following formulas: ； In the formula, This is the final value of the rotor position. This is the final value of the rotor speed. This is the initial value of the rotor position. This is the rotor position correction value. To estimate the rotor speed considering load torque, This is the rotor speed correction value.

9. A synchronous motor control device, characterized in that, The device includes: The flux linkage observer module is used to determine the preliminary values ​​of the rotor position and rotor speed of the synchronous motor. The correction module is used to determine the rotor position correction value and the rotor speed correction value based on the load torque of the synchronous motor. The rotor speed correction value is obtained according to the sign function to correct the preliminary rotor position value and the preliminary rotor speed value estimated under the fault convergence point condition of the flux linkage observer. The determining module is used to correct the preliminary values ​​of rotor position and rotor speed based on the rotor position correction value and rotor speed correction value to obtain the final values ​​of rotor position and rotor speed. The control module is used to control the start of the synchronous motor based on the final values ​​of the rotor position and rotor speed.

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