Counter electromotive force detection method, system and equipment of permanent magnet gyro motor, medium and product

Abstract

The invention discloses a counter electromotive force detection method, system and device of a permanent magnet gyro motor, a medium and a product, and relates to the technical field of motor control, the method comprises the following steps: when the rotating speed of the permanent magnet gyro motor is less than a preset threshold, determining the moment of any phase current peak value in each current period as the injection moment of a blocking vector; determining the shortest injection time based on the filtering parameters of the post-stage LC filter; determining the maximum injection time based on the friction torque of the permanent magnet gyro motor when vector injection is blocked; based on the injection time, the shortest injection time and the maximum injection time of the blocking vector, blocking vector injection is carried out on the permanent magnet gyroscope motor until the permanent magnet gyroscope motor has the phenomena of current zero drop, filter inductor follow current stop and sliding deceleration; and acquiring the three-phase terminal voltage at the current moment and determining the back electromotive force of the permanent magnet gyro motor at the current moment based on the three-phase terminal voltage. According to the invention, the effectiveness of counter electromotive force detection of the permanent magnet gyro motor is improved.

Description

Technical Field

[0001] The present application relates to the technical field of motor control, and particularly to a method, system, device, medium and product for detecting the back electromotive force of a permanent magnet gyro motor. Background Art

[0002] In a space navigation system, a high-precision gyro motor is the core of precise guidance. Traditional gyro motors use hysteresis motors, but the gyro accuracy is not high. In addition, sensorless algorithms have attracted much attention in recent years because they do not require the installation of sensors, which reduces the volume of the motor and the control complexity. Sensorless algorithms rely on the back electromotive force relationship estimation of the motor. However, the back electromotive force is proportional to the rotor speed. Since the back electromotive force is very small when the permanent magnet gyro motor rotates at a low speed, it is difficult to distinguish it from electromagnetic noise, etc. The coreless permanent magnet gyro motor cannot identify the back electromotive force information through high-frequency injection. And the stator of the new permanent magnet gyro motor uses non-magnetic materials. Therefore, in the early stage of motor startup, it is difficult to obtain the back electromotive force signal of the motor through the salient pole effect of the motor, which easily causes the motor to accelerate and lose synchronization.

[0003] Therefore, it is necessary to provide a method for detecting the back electromotive force of a permanent magnet gyro motor to solve the above problems. Summary of the Invention

[0004] The purpose of the present application is to provide a method, system, device, medium and product for detecting the back electromotive force of a permanent magnet gyro motor to improve the effectiveness of detecting the back electromotive force of the permanent magnet gyro motor.

[0005] To achieve the above purpose, the present application provides the following solutions:

[0006] In the first aspect, the present application provides a method for detecting the back electromotive force of a permanent magnet gyro motor. The permanent magnet gyro motor is connected to a control system, and the control system includes: a three-phase full-bridge inverter and a post-stage LC filter; the method for detecting the back electromotive force of the permanent magnet gyro motor includes:

[0007] When the speed of the permanent magnet gyro motor is less than a preset threshold, the moment when the peak value of any phase current in each current cycle is determined as the injection moment of the blocking vector;

[0008] Based on the filtering parameters of the post-stage LC filter, determine the shortest injection time of the blocking vector; wherein, the shortest injection time of the blocking vector is greater than the minimum inductive current continuation time after the switch tube is turned off;

[0009] Based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor when the blocking vector is injected, determine the maximum injection time of the blocking vector;

[0010] Based on the injection moment, the shortest injection time, and the maximum injection time of the blocking vector, perform blocking vector injection on the permanent magnet gyro motor until current zero-crossing occurs in the permanent magnet gyro motor, the freewheeling of the filter inductor stops, and the permanent magnet gyro motor decelerates while coasting. At this time, collect the three-phase terminal voltage of the permanent magnet gyro motor at the current moment.

[0011] Based on the three-phase terminal voltage of the permanent magnet gyro motor at the current moment, determine the back electromotive force of the permanent magnet gyro motor at the current moment.

[0012] Optionally, based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor during blocking vector injection, determine the maximum injection time of the blocking vector, specifically including:

[0013] Based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor during blocking vector injection and the mechanical motion equation of the permanent magnet gyro motor, obtain the relationship between the rotor speed and time of the permanent magnet gyro motor.

[0014] Based on the relationship between the rotor speed and time of the permanent magnet gyro motor, determine the maximum injection time of the blocking vector.

[0015] Optionally, based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor during blocking vector injection and the mechanical motion equation of the permanent magnet gyro motor, obtain the relationship between the rotor speed and time of the permanent magnet gyro motor, specifically including:

[0016] Substitute the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor during blocking vector injection into the mechanical motion equation of the permanent magnet gyro motor to obtain the first-order differential equation of the permanent magnet gyro motor.

[0017] Solve the first-order differential equation to obtain the relationship between the rotor speed and time of the permanent magnet gyro motor.

[0018] Optionally, the expression of the mechanical motion equation of the permanent magnet gyro motor is:

[0019]

[0020] where, T e is the electromagnetic torque of the permanent magnet gyro motor; T L is the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor; J is the moment of inertia of the permanent magnet gyro motor; ω is the rotational speed of the permanent magnet gyro motor; t is time.

[0021] Optionally, the relationship between the rotor speed and time of the permanent magnet gyro motor is:

[0022]

[0023] Where, ω is the rotor speed of the permanent magnet gyro motor; b is the friction coefficient during the rotation of the permanent magnet gyro motor; I is the current of the permanent magnet gyro motor.

[0024] Optionally, the expression of the back electromotive force of the permanent magnet gyro motor at the current moment is:

[0025]

[0026] v a =V m cosθ;

[0027] v b =V m cos(θ - 120°);

[0028] v c =V m cos(θ + 120°);

[0029] Where, V m is the back electromotive force of the permanent magnet gyro motor at the current moment; v a is the phase A terminal voltage; v b is the phase B terminal voltage; v c is the phase C terminal voltage; θ is the rotor angle.

[0030] In a second aspect, the present application provides a back electromotive force detection system for a permanent magnet gyro motor. The back electromotive force detection system for the permanent magnet gyro motor is used to implement the back electromotive force detection method of the permanent magnet gyro motor; the permanent magnet gyro motor is connected to a control system, and the control system includes: a three-phase full-bridge inverter and a post-stage LC filter; the back electromotive force detection system for the permanent magnet gyro motor includes:

[0031] An injection time determination unit, configured to determine, when the speed of the permanent magnet gyro motor is less than a preset threshold, the moment of any phase current peak value in each current cycle as the injection time of the blocking vector;

[0032] A shortest injection time determination unit, configured to determine the shortest injection time of the blocking vector based on the filtering parameters of the post-stage LC filter; wherein, the shortest time for injecting the blocking vector is greater than the minimum inductive current continuation time after the switch tube is turned off;

[0033] A maximum injection time determination unit, configured to determine the maximum injection time of the blocking vector based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor during the injection of the blocking vector;

[0034] A three-phase terminal voltage determination unit is configured to perform blocking vector injection on the permanent magnet gyro motor based on the injection time, the shortest injection time, and the maximum injection time of the blocking vector, and collect the three-phase terminal voltage of the permanent magnet gyro motor at the current moment until current zero-crossing, the filtering inductor stops freewheeling, and the permanent magnet gyro motor coasts and decelerates occur in the permanent magnet gyro motor.

[0035] An electromotive force determination unit is configured to determine the back electromotive force of the permanent magnet gyro motor at the current moment based on the three-phase terminal voltage of the permanent magnet gyro motor at the current moment.

[0036] In a third aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the computer program to implement the back electromotive force detection method of the permanent magnet gyro motor described in any one of the above.

[0037] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the back electromotive force detection method of the permanent magnet gyro motor described in any one of the above.

[0038] In a fifth aspect, the present application provides a computer program product, including a computer program, and when the computer program is executed by a processor, it implements the back electromotive force detection method of the permanent magnet gyro motor described in any one of the above.

[0039] According to the specific embodiments provided by the present application, the present application has the following technical effects:

[0040] The present application discloses a back electromotive force detection method, system, device, medium, and product for a permanent magnet gyro motor. When the permanent magnet gyro motor operates at a low speed (i.e., the speed is less than a preset threshold), the back electromotive force of the permanent magnet gyro motor is too small and mixed in the switching noise. By injecting a blocking vector into the permanent magnet gyro motor and detecting the motor back electromotive force within a short injection time, the motor back electromotive force is detected under the condition of basically not affecting the starting torque of the motor. By injecting the blocking vector, a clean back electromotive force signal can be extracted, improving the effectiveness of the back electromotive force detection of the permanent magnet gyro motor. Description of the Drawings

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0042] Figure 1Schematic diagram of the back electromotive force detection method for a permanent magnet gyro motor provided by an embodiment of the present application;

[0043] Figure 2 Schematic diagram of an inverter bridge plus a filter circuit provided by an embodiment of the present application;

[0044] Figure 3 Schematic diagram of the rotational speed of a permanent magnet gyro motor under wind resistance provided by an embodiment of the present application;

[0045] Figure 4 Schematic diagram of the simulation of the downsampling process under the blocking vector injection window provided by an embodiment of the present application;

[0046] Figure 5 Schematic diagram of the structure of a computer device provided by an embodiment of the present application. Detailed implementation manners

[0047] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0048] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0049] In an exemplary embodiment, as Figure 1 shown, a method for detecting the back electromotive force of a permanent magnet gyro motor is provided. The permanent magnet gyro motor is connected to a control system, and a model of the control system of the permanent magnet gyro motor is constructed to obtain a control system model. The control system includes: a three-phase full-bridge inverter and a subsequent LC filter. That is, a subsequent LC filter is added to the basis of the traditional control system of the permanent magnet gyro motor, and then the subsequent LC filter is connected to the motor (i.e., the permanent magnet gyro motor) to obtain an equivalent circuit of the inverter bridge during the starting process of the permanent magnet gyro motor abstracted as Figure 2 shown. The method for detecting the back electromotive force of the permanent magnet gyro motor includes:

[0050] Step S1, when the rotational speed of the permanent magnet gyro motor is less than a preset threshold, the moment corresponding to the peak value of any phase current in each current cycle is determined as the injection moment of the blocking vector. In this embodiment, the injection at the peak value of the A-phase current is taken as an example for illustration.

[0051] Step S2, determine the shortest injection time of the blocking vector based on the filtering parameters of the post-stage LC filter; wherein, the shortest injection time of the blocking vector is greater than the minimum inductive current continuation time after the switch is turned off. Since the inductor continues to conduct current after the switch is turned off, and the current continuation time is the minimum time for injecting the blocking vector, the blocking time (i.e., the injection time of the blocking vector) should be greater than the minimum inductive current continuation time.

[0052] Step S3, determine the maximum injection time of the blocking vector based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor when the blocking vector is injected. That is, the blocking time should be less than the maximum injection time of the blocking vector.

[0053] As an alternative implementation, step S3 specifically includes:

[0054] Step S31, based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor when the blocking vector is injected and the mechanical motion equation of the permanent magnet gyro motor, obtain the relationship between the rotor speed and time of the permanent magnet gyro motor.

[0055] As an alternative implementation, step S31 specifically includes:

[0056] Step S311, substitute the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor when the blocking vector is injected into the mechanical motion equation of the permanent magnet gyro motor to obtain the first-order differential equation of the permanent magnet gyro motor.

[0057] Among them, the expression of the mechanical motion equation of the permanent magnet gyro motor is:

[0058]

[0059] Among them, T e is the electromagnetic torque of the permanent magnet gyro motor; T L is the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor; J is the moment of inertia of the permanent magnet gyro motor; ω is the rotational speed of the permanent magnet gyro motor.

[0060] Step S312, solve the first-order differential equation to obtain the relationship between the rotor speed and time of the permanent magnet gyro motor.

[0061] Among them, the relationship between the rotor speed and time of the permanent magnet gyro motor is:

[0062]

[0063] Among them, ω is the rotor speed of the permanent magnet gyro motor; b is the friction coefficient during the rotation of the permanent magnet gyro motor; I is the current of the permanent magnet gyro motor.

[0064] Step S32: Determine the maximum injection time of the blocking vector based on the relationship between the rotor speed and time of the permanent magnet gyro motor.

[0065] Specifically, the fluid medium of the bearing of the permanent magnet gyro motor is helium. Under standard conditions, its dynamic viscosity is 1.89×10 -5 Pa·s. Under this working condition, the flow state of helium in the bearing gas film is laminar. When the bearing is suspended, the wind resistance torques borne by the rotor and the stator are equal in magnitude and opposite in direction. The calculation formula for the wind resistance power of the rotor (or stator) is:

[0066]

[0067] where P is the wind resistance power, μ is the dynamic viscosity of air, r is the inner diameter of the gas film, and Δr is the thickness of the gas film.

[0068] The relationship between the wind resistance power and the wind resistance torque (i.e., the frictional torque generated by the gas film wind resistance of the permanent magnet gyro motor) is:

[0069] P = T L ω(4)

[0070] Then the wind resistance torques of the rotor and the stator can be obtained:

[0071]

[0072] The friction coefficient during the rotation process can be obtained as:

[0073]

[0074] The electromagnetic torque expression of the permanent magnet gyro motor is as follows:

[0075]

[0076] where p m is the number of pole pairs; is the rotor magnetic flux; i q is the quadrature axis current; I s is the stator current; δ is the power angle.

[0077] When the blocking vector is injected, the motor current drops to 0 within the blocking time. At this time, it is considered that there is no electromagnetic torque acting, T e = 0, and only the gas frictional torque generated by the wind resistance exists. The motor speed will gradually decrease. Substituting the frictional torque into the mechanical motion equation of the permanent magnet gyro motor, the corresponding first-order differential equation can be obtained as follows:

[0078]

[0079] Solving the first-order differential equation (i.e., Equation (8)) can obtain the relationship between the rotor speed and time of the permanent magnet gyro motor as shown in Equation (2). Solving Equation (8) gives the relationship between speed and time. In the case of only wind resistance torque, the speed continuously drops. As can be seen from Figure 3 it, due to the absence of electromagnetic torque, the motor speed will decrease. After 700 μs, it drops by about 10 rpm, that is, 1.04 rad / s. If the injected blocking vector causes a speed drop of 10 rpm, it will cause great interference to the control of the entire system. To ensure control accuracy and system stability, the total injection time of the blocking vector should be less than 700 μs. Set the maximum allowable injection time as T max , and the relationship can be obtained:

[0080] nT b ≤ T max (9)

[0081] Step S4: Based on the injection moment, the shortest injection time, and the maximum injection time of the blocking vector, inject the blocking vector into the permanent magnet gyro motor until current zero-crossing, the filtering inductor stops freewheeling, and the permanent magnet gyro motor decelerates while coasting occur in the permanent magnet gyro motor, and collect the three-phase terminal voltage of the permanent magnet gyro motor at the current moment. After the blocking time T b , collect the motor voltage at this time (i.e., the three-phase terminal voltage of the permanent magnet gyro motor at the current moment).

[0082] Step S5: Based on the three-phase terminal voltage of the permanent magnet gyro motor at the current moment, determine the back electromotive force of the permanent magnet gyro motor at the current moment.

[0083] Among them, the expression of the back electromotive force of the permanent magnet gyro motor at the current moment is:

[0084]

[0085] v a =V m cosθ(11)

[0086] v b =V m cos(θ - 120°)(12)

[0087] v c =V m cos(θ + 120°)(13)

[0088] Among them, V m is the back electromotive force of the permanent magnet gyro motor at the current moment; v a is the phase A terminal voltage; v b is the phase B terminal voltage; v cis the terminal voltage of phase C; θ is the rotor angle.

[0089] Furthermore, Figure 4 is a schematic diagram of the simulation of the downsampling process of the blocking vector injection window, as Figure 4 shown. It can be obtained from the simulation that after the transient component decays, the terminal voltage of the motor is collected using an analog acquisition time of about 10 μs. The back electromotive force Ve a basically coincides with the actual back electromotive force E of the motor a of the motor, and the difference between the collected terminal voltage v a and the actual back electromotive force E a is ≤ 5%, which can be used as the actual back electromotive force, that is, it verifies that the back electromotive force detection method of the permanent magnet gyro motor of the present application can obtain the accurate back electromotive force of the motor at the moment of blocking vector injection.

[0090] Advantages of the present application:

[0091] 1) The back electromotive force signal extracted by traditional back electromotive force detection is mixed with electromagnetic noise and needs to be filtered by a filter, but it will cause system delay and the detection accuracy is not high. The present application is suitable for improving the effective back electromotive force detection of the motor in the low-speed section. When the motor is running at low speed, the back electromotive force is too small and mixed in the switching noise. By injecting a blocking vector, a clean back electromotive force signal can be extracted, and the back electromotive force of the motor can be detected within a short injection time.

[0092] 2) Design an observer for the back electromotive force of the motor under the blocking vector insertion interval to detect the position of the motor rotor under the condition of basically not affecting the starting torque of the motor. The detected weak back electromotive force signal improves the effectiveness and accuracy of the back electromotive force detection of the magnetic gyro motor.

[0093] 3) Using the detected weak back electromotive force signal to obtain accurate back electromotive force information lays a foundation for the subsequent sensorless algorithm.

[0094] 4) The present application uses a permanent magnet synchronous motor for the gyro motor, which can achieve the goals of high precision, low vibration and noise control.

[0095] Based on the same inventive concept, the embodiment of the present application also provides a back electromotive force detection system for a permanent magnet gyro motor for implementing the above-mentioned back electromotive force detection method of the permanent magnet gyro motor. The implementation solutions provided by this system to solve problems are similar to the implementation solutions described in the above method. Therefore, the specific limitations in one or more embodiments of the back electromotive force detection system for a permanent magnet gyro motor provided below can refer to the limitations on the back electromotive force detection method of the permanent magnet gyro motor in the above text, and will not be repeated here.

[0096] In an exemplary embodiment, an electromotive force detection system for a permanent magnet gyro motor is provided. The permanent magnet gyro motor is connected to a control system, and the control system includes a three-phase full-bridge inverter and a post-stage LC filter. The electromotive force detection system for the permanent magnet gyro motor includes:

[0097] An injection time determination unit, configured to determine, when the rotation speed of the permanent magnet gyro motor is less than a preset threshold, the time at which any phase current peak in each current cycle is located as the injection time of the blocking vector.

[0098] A shortest injection time determination unit, configured to determine the shortest injection time of the blocking vector based on the filtering parameters of the post-stage LC filter; wherein, the shortest time for injecting the blocking vector is greater than the minimum inductive current continuation time after the switch is turned off.

[0099] A maximum injection time determination unit, configured to determine the maximum injection time of the blocking vector based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor during the injection of the blocking vector.

[0100] A three-phase terminal voltage determination unit, configured to perform blocking vector injection on the permanent magnet gyro motor based on the injection time, shortest injection time, and maximum injection time of the blocking vector, and collect the three-phase terminal voltage of the permanent magnet gyro motor at the current moment until current zero-crossing, filtering inductor current continuation stop, and permanent magnet gyro motor coasting deceleration occur in the permanent magnet gyro motor.

[0101] An electromotive force determination unit, configured to determine the electromotive force of the permanent magnet gyro motor at the current moment based on the three-phase terminal voltage of the permanent magnet gyro motor at the current moment.

[0102] In an exemplary embodiment, a computer device is provided, including a memory, a processor, and a computer program stored on the memory and executable on the processor. The processor executes the computer program to implement the method for detecting the electromotive force of a permanent magnet gyro motor.

[0103] In an exemplary embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method for detecting the electromotive force of a permanent magnet gyro motor is implemented.

[0104] In an exemplary embodiment, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the method for detecting the electromotive force of a permanent magnet gyro motor is implemented.

[0105] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal, and its internal structure diagram may be as Figure 5As shown in the figure. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it realizes a method for detecting the back electromotive force of a permanent magnet gyro motor.

[0106] Those skilled in the art can understand that Figure 5 the structure shown in the figure is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0107] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0108] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0109] The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logics, data processing logics based on quantum computing, etc., without limitation.

[0110] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0111] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A method for detecting the back electromotive force of a permanent magnet gyro motor, characterized in that The permanent magnet gyro motor is connected to a control system, and the control system includes: a three-phase full-bridge inverter and a post-stage LC filter; the method for detecting the back electromotive force of the permanent magnet gyro motor includes: When the rotational speed of the permanent magnet gyro motor is less than a preset threshold, determine the moment when the peak value of any phase current in each current cycle is located as the injection moment of the blocking vector; Based on the filtering parameters of the post-stage LC filter, determine the shortest injection time of the blocking vector; wherein, the shortest injection time of the blocking vector is greater than the minimum inductive current continuation time after the switching tube is turned off; Based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor during the injection of the blocking vector, determine the maximum injection time of the blocking vector; Based on the injection moment, the shortest injection time, and the maximum injection time of the blocking vector, inject the blocking vector into the permanent magnet gyro motor until current zero-crossing, the filtering inductor stops current continuation, and the permanent magnet gyro motor coasts and decelerates occur, and collect the three-phase terminal voltages of the permanent magnet gyro motor at the current moment; Based on the three-phase terminal voltages of the permanent magnet gyro motor at the current moment, determine the back electromotive force of the permanent magnet gyro motor at the current moment.

2. The back electromotive force detection method of the permanent magnet gyro motor according to claim 1, characterized in that Based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor during the injection of the blocking vector, determine the maximum injection time of the blocking vector, specifically including: Based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor during the injection of the blocking vector and the mechanical motion equation of the permanent magnet gyro motor, obtain the relational expression between the rotor speed and time of the permanent magnet gyro motor; Based on the relational expression between the rotor speed and time of the permanent magnet gyro motor, determine the maximum injection time of the blocking vector.

3. The back electromotive force detection method of the permanent magnet gyro motor according to claim 2, characterized in that, Based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor during the injection of the blocking vector and the mechanical motion equation of the permanent magnet gyro motor, obtain the relational expression between the rotor speed and time of the permanent magnet gyro motor, specifically including: Substitute the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor during the injection of the blocking vector into the mechanical motion equation of the permanent magnet gyro motor to obtain the first-order differential equation of the permanent magnet gyro motor; Solve the first-order differential equation to obtain the relational expression between the rotor speed and time of the permanent magnet gyro motor.

4. The back electromotive force detection method of the permanent magnet gyro motor according to claim 2, characterized in that The expression of the mechanical motion equation of the permanent magnet gyro motor is: Among them, T e is the electromagnetic torque of the permanent magnet gyro motor; T L is the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor; J is the moment of inertia of the permanent magnet gyro motor; ω is the rotational speed of the permanent magnet gyro motor; t is the time.

5. The method for detecting the back electromotive force of the permanent magnet gyro motor according to claim 3, wherein The relational expression between the rotor speed and time of the permanent magnet gyro motor is: Wherein, ω is the rotor speed of the permanent magnet gyro motor; b is the friction coefficient during the rotation of the permanent magnet gyro motor; I is the current of the permanent magnet gyro motor at the current moment.

6. The back electromotive force detection method of the permanent magnet gyro motor according to claim 1, characterized in that The expression of the back electromotive force of the permanent magnet gyro motor at the current moment is: v a = V m cosθ; v b = V m cos(θ - 120°); v c = V m cos(θ + 120°); Among them, V m is the back electromotive force of the permanent magnet gyro motor at the current moment; v a is the phase A terminal voltage; v b is the phase B terminal voltage; v c is the phase C terminal voltage; θ is the rotor angle.

7. A back electromotive force detection system for a permanent magnet gyro motor, characterized in that The back electromotive force detection system of the permanent magnet gyro motor is used to implement the method for detecting the back electromotive force of the permanent magnet gyro motor according to any one of claims 1-6; The permanent magnet gyro motor is connected to a control system, and the control system includes: a three-phase full-bridge inverter and a post-stage LC filter; the back electromotive force detection system of the permanent magnet gyro motor includes: An injection moment determination unit, configured to, when the rotational speed of the permanent magnet gyro motor is less than a preset threshold, determine the moment when the peak value of any phase current in each current cycle is located as the injection moment of the blocking vector; The shortest injection time determination unit is configured to determine the shortest injection time of the blocking vector based on the filtering parameters of the subsequent LC filter; wherein, the shortest time for injecting the blocking vector is greater than the minimum inductive freewheeling time after the switch tube is turned off; The maximum injection time determination unit is configured to determine the maximum injection time of the blocking vector based on the frictional torque generated by the air film wind resistance of the permanent magnet gyro motor during the injection of the blocking vector; The three-phase terminal voltage determination unit is configured to perform blocking vector injection on the permanent magnet gyro motor based on the injection moment, the shortest injection time, and the maximum injection time of the blocking vector, and collect the three-phase terminal voltage of the permanent magnet gyro motor at the current moment until current zero-crossing, filtering inductor freewheeling stop, and permanent magnet gyro motor coasting deceleration occur in the permanent magnet gyro motor; The back electromotive force determination unit is configured to determine the back electromotive force of the permanent magnet gyro motor at the current moment based on the three-phase terminal voltage of the permanent magnet gyro motor at the current moment.

8. A computer device, comprising: A memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement the back electromotive force detection method of the permanent magnet gyro motor according to any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the back electromotive force detection method of the permanent magnet gyro motor according to any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the back electromotive force detection method of the permanent magnet gyro motor according to any one of claims 1-6.

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