Synchronous motor control method and device

Abstract

The invention discloses a synchronous motor control method and device. The method comprises the following steps: determining a rotor position initial value and a rotor speed initial value of a synchronous motor based on a flux observer; then determining a rotor position correction value and a rotor speed correction value based on the load torque of the synchronous motor; correcting the initial value of the rotor position and the initial value of the rotor speed according to the corrected value of the rotor position and the corrected value of the rotor speed to obtain a final value of the rotor position and a final value of the rotor speed; and finally, starting the synchronous motor based on the final value of the rotor position and the final value of the rotor speed, so that starting control can be performed on the synchronous motor more accurately and quickly, and an independent initial position identification process does not need to be performed.

Description

Technical Field

[0001] The present invention belongs to the technical field of synchronous motors, and particularly relates to a synchronous motor control method and device. Background Art

[0002] Conventional synchronous motors usually use a flux observer to estimate the rotor position and speed of the synchronous motor during startup control, thereby controlling the startup of the synchronous motor. However, this type of method is prone to convergence to an incorrect convergence point under working conditions where the initial position of the synchronous motor is unknown, which then causes the synchronous motor to stall during load startup. The current solution is to use a separate initial position identification stage to obtain the initial position of the synchronous motor offline before each startup of the synchronous motor. However, the initial position identification method of the synchronous motor has high requirements on the sampling accuracy of the motor control system, and the identification process is cumbersome.

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

[0004] The purpose of the present invention is to solve the technical problems in the prior art of using a flux observer to control the startup of a synchronous motor, which easily causes a stall fault or requires a position observer to identify the initial position of the motor, resulting in cumbersome control.

[0005] To achieve the above technical objectives, the present invention provides a synchronous motor control method, which includes: Determine the preliminary value of the rotor position and the preliminary value of the rotor speed of the synchronous motor based on the flux observer; determining a rotor position correction value and a rotor speed correction value based on the load torque of the synchronous motor; Correcting the preliminary rotor position value and the preliminary rotor speed value according to the rotor position correction value and the rotor speed correction value to obtain a final rotor position value and a final rotor speed value; The synchronous motor is started by controlling the rotor position final value and the rotor speed final value.

[0006] Furthermore, determining the preliminary rotor position value and the preliminary rotor speed value of the synchronous motor based on the flux observer specifically includes: The stator flux vector estimation value in the stationary coordinate system is determined by the flux observer. Quantity and Quantity; According to the stator flux vector estimation value in the stationary coordinate system Quantity and The rotor flux vector estimation value in the stationary coordinate system is determined by the component Quantity and Quantity; Based on the rotor flux vector estimation value in the stationary coordinate system Quantity and The components determine the preliminary value of the rotor position and the preliminary value of the rotor speed.

[0007] Furthermore, the flux observer is specifically shown in the following formula: , Where, is the estimated value of the stator flux vector in the stationary coordinate system Quantity, is the estimated value of the stator flux vector in the stationary coordinate system Quantity, is the stator voltage vector in the stationary coordinate system Quantity, is the stator voltage vector in the stationary coordinate system Quantity, is the stator resistance, is the stator current vector in the stationary coordinate system Quantity, is the stator current vector in the stationary coordinate system Quantity, is the correction term of the flux observer in the stationary coordinate system Quantity, is the correction term of the flux observer in the stationary coordinate system Quantity, d is the differential operator, t For time.

[0008] Furthermore, the preliminary value of the rotor position and the preliminary value of the rotor speed are determined specifically by the following formula: , Where, is the initial value of the rotor position, is the initial value of the rotor speed, is the inverse tangent function, is the estimated value of the rotor flux vector in the stationary coordinate system Quantity, is the rotor flux vector in the stationary coordinate system Quantity, d is the differential operator, t For time.

[0009] Furthermore, the rotor position correction value and the rotor speed correction value are determined based on the load torque of the synchronous motor, specifically by the following formula: , Where, is the rotor speed correction value, is the rotor position correction value, is a symbolic function, is the electromagnetic torque, To estimate the rotor speed considering the load torque, is the load torque, is the target speed of the synchronous motor.

[0010] Furthermore, the estimated value of the rotor speed considering the load torque is specifically determined by the following formula: , Where, is the load torque estimation gain, is the mechanical inertia of the system, is the initial value of the rotor speed, d is the differential operator, t For time, is the load torque.

[0011] Furthermore, the load torque is specifically determined by the following formula: , Where, Estimate the gain for the load torque.

[0012] Furthermore, the final value of the rotor position and the final value of the rotor speed are obtained specifically through the following formulas: , Where, is the final value of the rotor position, is the final value of the rotor speed, is the initial value of the rotor position, is the rotor position correction value, To estimate the rotor speed considering the load torque, is the rotor speed correction value.

[0013] On the other hand, the present application also provides a synchronous motor control device, the device comprising: The flux observer module is used to determine the preliminary value of the rotor position and the preliminary value of the rotor speed of the synchronous motor; a correction module, configured to determine a rotor position correction value and a rotor speed correction value based on the load torque of the synchronous motor; a determination module, configured to correct the preliminary rotor position value and the preliminary rotor speed value according to the rotor position correction value and the rotor speed correction value to obtain a final rotor position value and a final rotor speed value; A control module is configured to control starting of the synchronous motor based on the rotor position final value and the rotor speed final value.

[0014] The present invention provides a synchronous motor control method and device. Compared with the prior art, the method first determines a preliminary rotor position value and a preliminary rotor speed value of the synchronous motor based on a flux observer; then determines a rotor position correction value and a rotor speed correction value based on the load torque of the synchronous motor; then, the preliminary rotor position value and the preliminary rotor speed value are corrected according to the rotor position correction value and the rotor speed correction value to obtain a final rotor position value and a final rotor speed value; finally, the synchronous motor is started based on the final rotor position value and the final rotor speed value, which can more accurately and quickly control the start-up of the synchronous motor without the need for a separate initial position identification process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 FIG2 is a flow chart of a synchronous motor control method provided in an embodiment of this specification; Figure 2 The figure shows the structure of the synchronous motor control device provided in the embodiment of this specification. Figure 3 Shown is a schematic diagram of the two-phase rotor flux at different initial positions. DETAILED DESCRIPTION

[0017] In order 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 in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0018] like Figure 1The flowchart of the synchronous motor control method provided in the embodiment of this specification is shown. Although this specification provides the method operation steps or device structure shown in the following embodiment or drawings, the method or device may include more or fewer operation steps or module units after partial combination based on routine or no creative work. In the steps or structures that do not logically have a necessary causal relationship, the execution order of these steps or the module structure of the device is not limited to the execution order or module structure shown in the embodiment or drawings of this specification. When the method or module structure is applied in an actual device, server or terminal product, it can be executed sequentially or in parallel according to the method or module structure shown in the embodiment or drawings (for example, in a parallel processor or multi-threaded processing environment, or even in a distributed processing or server cluster implementation environment).

[0019] 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: Step S101: Determine a preliminary rotor position value and a preliminary rotor speed value of the synchronous motor based on a flux observer.

[0020] In the embodiment of the present application, determining the preliminary rotor position value and the preliminary rotor speed value of the synchronous motor based on the flux observer specifically includes: The stator flux vector estimation value in the stationary coordinate system is determined by the flux observer. Quantity and Quantity; According to the stator flux vector estimation value in the stationary coordinate system Quantity and The rotor flux vector estimation value in the stationary coordinate system is determined by the component Quantity and Quantity; Based on the rotor flux vector estimation value in the stationary coordinate system Quantity and The components determine the preliminary value of the rotor position and the preliminary value of the rotor speed.

[0021] Specifically, the stator flux equation of the synchronous motor in a two-phase stationary coordinate system is as follows: , Where, is the stator flux vector in the stationary coordinate system Quantity, is the stator flux vector in the stationary coordinate system Quantity.

[0022] The stator flux equation of the synchronous motor in a two-phase stationary coordinate system can also be described as a function of the rotor position, as shown below: , Where, is the stator flux vector in the stationary coordinate system considering the rotor position. Quantity, is the stator flux vector in the stationary coordinate system considering the rotor position. Quantity, is the rotor flux amplitude, L is the stator inductance.

[0023] According to the above stator flux equation and the function of rotor position, a flux observer based on a hybrid model can be constructed. The flux observer is specifically shown in the following formula: , Where, is the estimated value of the stator flux vector in the stationary coordinate system Quantity, is the estimated value of the stator flux vector in the stationary coordinate system Quantity, is the stator voltage vector in the stationary coordinate system Quantity, is the stator voltage vector in the stationary coordinate system Quantity, is the stator resistance, is the stator current vector in the stationary coordinate system Quantity, is the stator current vector in the stationary coordinate system Quantity, is the correction term of the flux observer in the stationary coordinate system Quantity, is the correction term of the flux observer in the stationary coordinate system Quantity, d is the differential operator, t For time.

[0024] in, and It can be determined by the following formula: , Where, is the proportional gain in the correction term of the flux observer, is the integral gain in the correction term of the flux observer.

[0025] According to the above, the estimated value of the stator flux vector in the stationary coordinate system is determined Quantity and The rotor flux vector estimation value in the stationary coordinate system can be determined by the following formula: Quantity and Quantity; , Then the preliminary value of the rotor position and the preliminary value of the rotor speed are determined by the following formula: , Where, is the initial value of the rotor position, is the initial value of the rotor speed, is the inverse tangent function, is the estimated value of the rotor flux vector in the stationary coordinate system Quantity, is the rotor flux vector in the stationary coordinate system Quantity, d is the differential operator, t For time, through and The respective positive and negative signs can realize the calculation of the inverse tangent function of the four quadrants.

[0026] Step S102: Determine a rotor position correction value and a rotor speed correction value based on the load torque of the synchronous motor.

[0027] Specifically, such as Figure 3 The figure shows the schematic diagram of two-phase rotor flux at different initial positions. Figure 3 From top to bottom, the rotor flux diagram under the working condition of forward rotation and initial position 0, the rotor flux diagram under the working condition of reverse rotation and initial position 0, and the rotor flux diagram under the working condition of reverse rotation and initial position π are shown. 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 dotted line in the figure indicates the initial position is π, that is, the initial state of the rotor flux vector. The initial states of the rotor flux vector in the forward rotation and initial position 0 working condition and the reverse rotation and initial position π working condition are the same, that is, Figure 3 The initial state of the rotor flux under the working condition of forward rotation and initial position 0 is the same as the initial state of the rotor flux under the working condition of reverse rotation and initial position π. This will result in the flux observer eventually converging 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 and thus cause a stall.

[0028] The present application solution extracts load torque information from the motor speed estimated by the flux observer, and performs secondary correction on the motor position and speed estimated under the condition of the wrong convergence point of the flux observer by comprehensively judging the electric power generation state corresponding to the load torque and the electric power generation state corresponding to the electromagnetic torque, so that the flux observer can converge to the correct convergence point under any initial position error condition, thereby ensuring that the synchronous motor can directly operate under the control of this new position sensorless method without the need for a separate initial position identification stage.

[0029] First, determine the electromagnetic torque equation of the synchronous motor as follows: , Where, is the number of motor pole pairs.

[0030] Based on the electromagnetic torque equation, the expression of the load torque of the synchronous motor can be obtained as follows: , Where, and Both are load torque estimation gains.

[0031] In the embodiment of the present application, the rotor position correction value and the rotor speed correction value are determined based on the load torque of the synchronous motor, specifically by the following formula: , Where, is the rotor speed correction value, is the rotor position correction value, is a symbolic function, For example, when When it is greater than or equal to 0, is 1, otherwise is -1, is the electromagnetic torque, To estimate the rotor speed considering the load torque, is the load torque, is the target speed of the synchronous motor.

[0032] The rotor speed estimation value considering the load torque is specifically determined by the following formula: , Where, is the load torque estimation gain, is the mechanical inertia of the system, is the initial value of the rotor speed, d is the differential operator, t For time, is the load torque.

[0033] The load torque is specifically determined by the following formula: , Where, Estimate the gain for the load torque.

[0034] Step S103 : Correcting the preliminary rotor position value and the preliminary rotor speed value according to the rotor position correction value and the rotor speed correction value to obtain a final rotor position value and a final rotor speed value.

[0035] In the embodiment of the present application, the final value of the rotor position and the final value of the rotor speed are obtained specifically by the following formula: , Where, is the final value of the rotor position, is the final value of the rotor speed, is the initial value of the rotor position, is the rotor position correction value, To estimate the rotor speed considering the load torque, is the rotor speed correction value.

[0036] Step S104: Control and start the synchronous motor based on the final value of the rotor position and the final value of the rotor speed.

[0037] Specifically, after the final value of the rotor position and the final value of the rotor speed are determined, the synchronous motor can be controlled by the motor control system without the need for separate initial position identification.

[0038] Based on the above-mentioned synchronous motor control method, one or more embodiments of this specification also provide a platform and terminal for synchronous motor control. The platform or terminal may include devices, software, modules, plug-ins, servers, clients, etc. that use the methods described in the embodiments of this specification and are combined with necessary hardware implementation devices. Based on the same innovative concept, the system in one or more embodiments provided in the embodiments of this specification is as described in the following embodiments. Since the implementation scheme and method for solving the problem of the system are similar, the implementation of the specific system in the embodiments of this specification can refer to the implementation of the aforementioned method, and the repetitions will not be repeated. The terms "unit" or "module" used below can be a combination of software and / or hardware that implements the predetermined function. Although the system described in the following embodiments is preferably implemented in software, hardware and a combination of software and hardware are also possible and conceived.

[0039] Specifically, Figure 2 This is a schematic diagram of the module structure of an embodiment of the synchronous motor control device provided in this specification. Figure 2As shown, the synchronous motor control device provided in this specification includes: The flux observer module 201 is used to determine the preliminary value of the rotor position and the preliminary value of the rotor speed of the synchronous motor; A correction module 202 is configured to determine a rotor position correction value and a rotor speed correction value based on the load torque of the synchronous motor; A determination module 203 is configured to correct the preliminary rotor position value and the preliminary rotor speed value according to the rotor position correction value and the rotor speed correction value to obtain a final rotor position value and a final rotor speed value; The control module 204 is configured to control the starting of the synchronous motor based on the final value of the rotor position and the final value of the rotor speed.

[0040] It should be noted that the above-mentioned system may also include other implementation methods according to the description of the corresponding method embodiment. The specific implementation methods can refer to the description of the above-mentioned corresponding method embodiment, and will not be described one by one here.

[0041] An embodiment of the present application further provides an electronic device, including: processor; a memory for storing instructions executable by the processor; The processor is configured to execute the method provided in the above embodiment.

[0042] The electronic device provided in the embodiment of the present application stores executable instructions of the processor in a memory. When the processor executes the executable instructions, it can first determine the preliminary rotor position value and the preliminary rotor speed value of the synchronous motor based on the flux observer; then determine the rotor position correction value and the rotor speed correction value based on the load torque of the synchronous motor; then correct the preliminary rotor position value and the preliminary rotor speed value according to the rotor position correction value and the rotor speed correction value to obtain the final rotor position value and the final rotor speed value; finally, control the start-up of the synchronous motor based on the final rotor position value and the final rotor speed value, so that the start-up control of the synchronous motor can be performed more accurately and quickly without the need for a separate initial position identification process.

[0043] The foregoing description of this specification describes specific embodiments. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in an order different from that described in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order shown or the sequential order to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0044] The methods or devices described in the above embodiments of this specification can implement business logic through computer programs and record them on storage media. The storage media can be read and executed by a computer to achieve the effects of the solutions described in the embodiments of this specification, such as: Determine the preliminary value of the rotor position and the preliminary value of the rotor speed of the synchronous motor based on the flux observer; determining a rotor position correction value and a rotor speed correction value based on the load torque of the synchronous motor; Correcting the preliminary rotor position value and the preliminary rotor speed value according to the rotor position correction value and the rotor speed correction value to obtain a final rotor position value and a final rotor speed value; The synchronous motor is started by controlling the rotor position final value and the rotor speed final value.

[0045] The storage medium may include a physical device for storing information, typically digitizing the information and then storing it in a medium utilizing electrical, magnetic, or optical means. Examples of such storage media include: devices that store information electrically, such as various types of memory devices like RAM and ROM; devices that store information magnetically, such as hard disks, floppy disks, magnetic tapes, magnetic core memories, bubble memories, and USB flash drives; and devices that store information optically, such as CDs and DVDs. Of course, other types of readable storage media exist, such as quantum memories and graphene memories.

[0046] The embodiments of this specification are not limited to those that must comply with industry communication standards, standard computer resource data update and data storage rules, or the situations described in one or more embodiments of this specification. Certain industry standards or slightly modified implementation plans based on the implementation described in the embodiments using custom methods or embodiments can also achieve the same, equivalent, or similar implementation effects as the above embodiments, or the expected implementation effects after deformation. The embodiments obtained by applying these modified or deformed data acquisition, storage, judgment, processing methods, etc. can still fall within the scope of the optional implementation plans of the embodiments of this specification.

[0047] The controller can be implemented in any suitable manner. For example, the controller 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 ATMEL AT91SAM, Microchip PIC18F26K20, and Silicon Labs C8051F320. The memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art will also appreciate that, in addition to implementing the controller in pure computer-readable program code, the controller can also be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, such a controller can be considered a hardware component, and the means for implementing various functions included therein 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.

[0048] The device embodiments described above are merely illustrative. For example, the division of units described is merely a logical functional division. Actual implementations may employ alternative divisions, such as combining or integrating multiple units or plug-ins into another system, or omitting or disabling certain features. Furthermore, the coupling or direct coupling or communication connection shown or discussed between devices or units may be through interfaces, or indirect coupling or communication connection between devices or units may be electrical, mechanical, or otherwise.

[0049] These computer program instructions can also be loaded onto a computer or other programmable resource data updating device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable device to implement the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0050] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from the other embodiments. In particular, since the system embodiments are generally similar to the method embodiments, their description is relatively simple, and relevant parts can be referenced to the partial description of the method embodiments. Throughout this specification, reference to the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of this specification. In this specification, the schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and integrate the different embodiments or examples, and features of different embodiments or examples, described in this specification, without conflict.

[0051] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific descriptions and embodiments. Those skilled in the art can make various other specific variations and combinations based on the technical teachings disclosed in the present invention without departing from the essence of the present invention, and such variations and combinations are still within the scope of protection of the present invention.

Claims

1. A synchronous motor control method, characterized in that: The method comprises: Determine the preliminary value of the rotor position and the preliminary value of the rotor speed of the synchronous motor based on the flux observer; determining a rotor position correction value and a rotor speed correction value based on the load torque of the synchronous motor; Correcting the preliminary rotor position value and the preliminary rotor speed value according to the rotor position correction value and the rotor speed correction value to obtain a final rotor position value and a final rotor speed value; The synchronous motor is started by controlling the rotor position final value and the rotor speed final value.

2. The synchronous motor control method according to claim 1, wherein: The determining of the preliminary rotor position value and the preliminary rotor speed value of the synchronous motor based on the flux observer specifically includes: The stator flux vector estimation value in the stationary coordinate system is determined by the flux observer. Quantity and Quantity; According to the stator flux vector estimation value in the stationary coordinate system Quantity and The rotor flux vector estimation value in the stationary coordinate system is determined by the component Quantity and Quantity; Based on the rotor flux vector estimation value in the stationary coordinate system Quantity and The components determine the preliminary value of the rotor position and the preliminary value of the rotor speed.

3. The synchronous motor control method according to claim 2, wherein: The flux observer is specifically shown in the following formula: ， Where, is the estimated value of the stator flux vector in the stationary coordinate system Quantity, is the estimated value of the stator flux vector in the stationary coordinate system Quantity, is the stator voltage vector in the stationary coordinate system Quantity, is the stator voltage vector in the stationary coordinate system Quantity, is the stator resistance, is the stator current vector in the stationary coordinate system Quantity, is the stator current vector in the stationary coordinate system Quantity, is the correction term of the flux observer in the stationary coordinate system Quantity, is the correction term of the flux observer in the stationary coordinate system Quantity, d is the differential operator, t For time.

4. The synchronous motor control method according to claim 2, wherein: Specifically, the preliminary value of the rotor position and the preliminary value of the rotor speed are determined by the following formula: ， Where, is the initial value of the rotor position, is the initial value of the rotor speed, is the inverse tangent function, is the estimated value of the rotor flux vector in the stationary coordinate system Quantity, is the rotor flux vector in the stationary coordinate system Quantity, d is the differential operator, t For time.

5. The synchronous motor control method according to claim 1, wherein: The rotor position correction value and the rotor speed correction value are determined based on the load torque of the synchronous motor, specifically by the following formula: ， Where, is the rotor speed correction value, is the rotor position correction value, is a symbolic function, is the electromagnetic torque, To estimate the rotor speed considering the load torque, is the load torque, is the target speed of the synchronous motor.

6. The synchronous motor control method according to claim 5, wherein: The rotor speed estimation value considering the load torque is specifically determined by the following formula: ， Where, is the load torque estimation gain, is the mechanical inertia of the system, is the initial value of the rotor speed, d is the differential operator, t For time, is the load torque.

7. The synchronous motor control method according to any one of claims 5 to 6, characterized in that: The load torque is specifically determined by the following formula: ， Where, Estimate the gain for the load torque.

8. The synchronous motor control method according to claim 1, wherein: Specifically, the final value of the rotor position and the final value of the rotor speed are obtained through the following formula: ， Where, is the final value of the rotor position, is the final value of the rotor speed, is the initial value of the rotor position, is the rotor position correction value, To estimate the rotor speed considering the load torque, is the rotor speed correction value.

9. A synchronous motor control device, characterized in that: The device comprises: The flux observer module is used to determine the preliminary value of the rotor position and the preliminary value of the rotor speed of the synchronous motor; a correction module, configured to determine a rotor position correction value and a rotor speed correction value based on the load torque of the synchronous motor; a determination module, configured to correct the preliminary rotor position value and the preliminary rotor speed value according to the rotor position correction value and the rotor speed correction value to obtain a final rotor position value and a final rotor speed value; A control module is configured to control starting of the synchronous motor based on the rotor position final value and the rotor speed final value.

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