Synchronous reluctance motor sensorless control method and system for mixed signal injection

Abstract

The invention discloses a sensorless control method and system for a synchronous reluctance motor with mixed signal injection, and the method comprises the steps: injecting a high-frequency mixed voltage signal at a d axis of an observation shaft system, the high-frequency mixed voltage signal is constructed through the mathematical change of four sine waves, and the integral of the injection voltage in a period is 0; performing dq / alpha beta conversion on the observation shaft system voltage injected with the high-frequency mixed voltage signal, and applying the voltage to the A, B and C three-phase winding voltage of the motor; the three-phase current of the motor is sampled, and the d-q axis high-frequency current of the observation shaft system is obtained through coordinate transformation; and decoupling processing is carried out on the obtained high-frequency current, and estimation of the position of the motor rotor is realized based on a phase-locked loop. The high-frequency mixed voltage signal can generate a lower high-frequency current fundamental wave characteristic, which has a remarkable effect on suppression of high-frequency torque and electromagnetic vibration when the motor runs.

Description

Technical Field

[0001] The present invention relates to the technical field of reluctance motors, and in particular to a sensorless control method and system for a synchronous reluctance motor with mixed signal injection. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Synchronous reluctance motors (SRMs) are becoming a strong alternative to permanent magnet and induction motors due to their simple structure, lack of permanent magnets and rotor windings, strong heat management capabilities, and low cost. To further reduce system costs, sensorless technology has been proposed and applied. However, in the zero- and low-speed regions, the extended back-EMF signal is susceptible to interference, making it difficult to accurately estimate the rotor position of a SRM. To improve sensorless control performance in these regions, high-frequency signal injection technology has been proposed. This method injects a high-frequency voltage signal into the motor while it is running. By observing the high-frequency current characteristics caused by the SRM's salient pole effect, it reliably estimates the SRM's rotor position. Consequently, this control method has become a leading solution for high-performance SRM drives.

[0004] However, the study found that the existing high-frequency signal injection technology will generate large high-frequency currents, which have a significant impact on the current noise, high-frequency torque fluctuations and electromagnetic vibrations of the synchronous reluctance motor, limiting the operation of this technology in harsh low-vibration precision environments, and is not conducive to the expansion of low-cost drive technology.

[0005] Although the existing technology discloses injection methods such as high-frequency square waves, high-frequency sine waves, and high-frequency rotating voltages, these signal injection methods do not modulate and reconstruct the current signal within each signal cycle. As a result, the fundamental component of the high-frequency current generated by these voltage injection technologies is not suppressed, and the signal cannot be adjusted from the source, and a direct suppression method cannot be provided for the current noise, high-frequency torque fluctuations, and electromagnetic vibration suppression of the synchronous reluctance motor. Summary of the Invention

[0006] In order to solve the above problems, the present invention proposes a sensorless control method and system for a synchronous reluctance motor with mixed signal injection, designs a mixed injection high-frequency voltage waveform, reduces the fundamental component of the high-frequency current in the motor circuit, realizes the suppression of the current noise of the synchronous reluctance motor near the injection frequency, and further reduces the high-frequency torque fluctuation and electromagnetic vibration of the synchronous reluctance motor.

[0007] In some embodiments, the following technical solutions are adopted:

[0008] A sensorless control method for a synchronous reluctance motor using mixed signal injection, comprising:

[0009] Inject a high-frequency mixed voltage signal into the d-axis of the observation axis system. The high-frequency mixed voltage signal is constructed by mathematically changing four sine waves, and the integral of the injected voltage within one cycle is 0.

[0010] The observed shaft voltage injected with the high-frequency mixed voltage signal is transformed into dq / αβ and applied to the three-phase winding voltages of the motor A, B, and C;

[0011] The three-phase current of the motor is sampled and the dq-axis high-frequency current of the observation axis system is obtained through coordinate transformation;

[0012] The obtained high-frequency current is decoupled and the motor rotor position is estimated based on a phase-locked loop.

[0013] As a further solution, the high-frequency mixed voltage signal is specifically:

[0014]

[0015] Among them, u dh is the high-frequency mixed voltage signal injected into the d-axis of the observation axis system, U inj is the amplitude of the injected high-frequency mixed voltage signal, f is the frequency of the injected high-frequency mixed voltage signal, t is the time, T i is the period of injecting high frequency mixed voltage signal.

[0016] As a further solution, considering the cross-saturation effect of the synchronous reluctance motor, the high-frequency current caused by the d-axis high-frequency mixed voltage signal is specifically:

[0017]

[0018] Among them, u dh is the high-frequency voltage signal injected into the d-axis of the observation axis system, is the dq axis correction inductance, is the dq axis cross-coupling inductance, is the d-axis incremental inductance, is the high-frequency current of the dq axis system, is the fundamental frequency current of the dq axis system.

[0019] As a further solution, after obtaining the motor rotor position estimate, the method further includes: compensating for inherent rotor estimation errors in combination with motor parameters.

[0020] As a further solution, the obtained high-frequency current is decoupled and the motor rotor position is estimated based on a phase-locked loop, specifically:

[0021] Multiplying the obtained high-frequency current by a transformation matrix to transform the high-frequency current from the observation axis system to the decoupled axis system;

[0022] Take the absolute value of the converted high-frequency current and divide it by the absolute value of the injected high-frequency voltage amplitude corresponding to the current high-frequency current to obtain the dq axis high-frequency current for rotor position estimation after decoupling and

[0023] By adjusting the PI parameters Converges to 0, achieving accurate tracking of the rotor position; Perform integration processing to obtain the angle and angular velocity of the rotor.

[0024] In other embodiments, the following technical solutions are adopted:

[0025] A sensorless control system for a synchronous reluctance motor with mixed signal injection, comprising:

[0026] A signal injection module is used to inject a high-frequency mixed voltage signal into the d-axis of the observation axis system. The high-frequency mixed voltage signal is constructed by mathematically changing four sine waves, and the integral of the injected voltage within one cycle is 0;

[0027] The motor power supply module is used to perform dq / αβ transformation on the observed shaft voltage injected with the high-frequency mixed voltage signal and apply it to the motor A, B, and C three-phase winding voltages;

[0028] The current sampling module is used to sample the three-phase current of the motor and obtain the dq-axis high-frequency current of the observation axis system through coordinate transformation;

[0029] The rotor position estimation module is used to decouple the obtained high-frequency current and estimate the motor rotor position based on a phase-locked loop.

[0030] As a further solution, the high-frequency mixed voltage signal is specifically:

[0031]

[0032] Among them, u dh is the high-frequency mixed voltage signal injected into the d-axis of the observation axis system, U inj is the amplitude of the injected high-frequency mixed voltage signal, f is the frequency of the injected high-frequency mixed voltage signal, t is the time, T i is the period of injecting high frequency mixed voltage signal.

[0033] In other embodiments, the following technical solutions are adopted:

[0034] A terminal device includes a processor and a memory, wherein the processor is used to implement instructions; the memory is used to store multiple instructions, and the instructions are suitable for the processor to load and execute the above-mentioned mixed signal injection synchronous reluctance motor sensorless control method.

[0035] In other embodiments, the following technical solutions are adopted:

[0036] A computer-readable storage medium stores a plurality of instructions, wherein the instructions are suitable for being loaded and executed by a processor of a terminal device to implement the above-mentioned sensorless control method for a synchronous reluctance motor with mixed signal injection.

[0037] In other embodiments, the following technical solutions are adopted:

[0038] A computer program product includes a computer program / instruction, which, when executed by a processor, implements the above-mentioned mixed signal injection synchronous reluctance motor sensorless control method.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) Since the existing technology focuses on high-frequency voltage injection technology of square waves and sine waves, the high-frequency current response generated is a triangular wave and a sine wave, and the fundamental component of the high-frequency current is still large, which cannot suppress the high-frequency signal from the source. The present invention designs a hybrid voltage injection signal. The hybrid signal is constructed by mathematically changing 4 sine waves. It can not only achieve a lower current fundamental component, but also meet the requirement that the injection voltage integral within one cycle is 0, which can ensure the periodicity of the high-frequency current caused by the injection signal and ensure that the low-frequency component of the current is not affected by the high-frequency signal. Experimental results show that the high-frequency hybrid voltage signal of the present invention can produce a lower high-frequency current fundamental wave feature, which has a significant effect on suppressing high-frequency torque and electromagnetic vibration when the motor is running.

[0041] Other features and advantages of additional aspects of the present invention will be given in part in the following description and in part will become obvious from the following description or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram comparing the high-frequency voltage and current of a high-frequency mixed voltage signal in an embodiment of the present invention and a square wave signal in the prior art; wherein (a) is a square wave signal, and (b) is a high-frequency mixed voltage signal;

[0043] Figure 2 The comparison of Fourier decomposition of current response under high-frequency mixed voltage signal and square wave voltage signal in the embodiment of the present invention;

[0044] Figure 3 Schematic diagram of a sensorless control method for a synchronous reluctance motor with mixed signal injection according to an embodiment of the present invention;

[0045] Figure 4 An experimental test platform built in the embodiments of the present invention;

[0046] Figure 5 Schematic diagram of the steady-state and dynamic test results of the motor under high-frequency square wave injection; (a) is the test result of 0RPM to 50RPM, and (b) is the test result of 50RPM to 100RPM;

[0047] Figure 6 Schematic diagram of the steady-state and dynamic test results of a motor under mixed signal injection in an embodiment of the present invention; wherein (a) is the test result of 0RPM to 50RPM, and (b) is the test result of 50RPM to 100RPM;

[0048] Figure 7 The following are the Fourier decomposition results of the steady-state current test of the motor according to the embodiment of the present invention and the prior art; (a) is at 50 RPM, and (b) is at 100 RPM;

[0049] Figure 8 The energy spectrum analysis results of the steady-state current test of the motor in the embodiment of the present invention and the prior art are shown; (a) is at 50 RPM, and (b) is at 100 RPM;

[0050] Figure 9 The following are Fourier transform results of the motor steady-state torque fluctuation under the high-frequency signal injection technology of the embodiment of the present invention and the prior art; wherein (a) is at 50RPM, and (b) is at 100RPM;

[0051] Figure 10 Figure 1 shows the results of the steady-state torque fluctuation energy spectrum of the motor under the high-frequency signal injection technology in the embodiment of the present invention and the prior art; (a) is at 50 RPM, and (b) is at 100 RPM;

[0052] Figure 11 These are the electromagnetic vibration test results of the motor under the high-frequency signal injection technology of the embodiment of the present invention and the prior art; wherein (a) is at 50 RPM, and (b) is at 100 RPM. DETAILED DESCRIPTION

[0053] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0054] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0055] Example 1

[0056] In one or more embodiments, a sensorless control method for a synchronous reluctance motor with mixed signal injection is disclosed, combined with Figure 3 , specifically including:

[0057] S101: In the observation axis system (i.e. Figure 3 Medium e -q e axis) and injects a high-frequency mixed voltage signal u dh .

[0058] In this embodiment, combined with Figure 3 , at a given dq axis fundamental frequency current and Based on the dq axis feedback current and Through PI regulation, the given dq axis voltage is obtained and On this basis, a given high-frequency voltage signal u is applied to the d-axis. dh .

[0059] The high-frequency mixed voltage signal u dh It is constructed by mathematically changing 4 sine waves to ensure that the integral of the injected voltage within one cycle is 0.

[0060] Specifically, the high-frequency mixed voltage signal expression of this embodiment is:

[0061]

[0062] Where u dh is the high-frequency voltage signal injected into the d-axis of the observation axis system, U inj is the amplitude of the injected voltage, f is the frequency of the injected high-frequency signal, t is the time, T i is the period of injected high frequency signal.

[0063] S102: Perform dq / αβ transformation on the observed shaft voltage injected with the high-frequency mixed voltage signal to obtain a mixed voltage with the high-frequency injected voltage. After SVPWM (space vector pulse width modulation), the three-phase winding voltage containing the high-frequency power signal is obtained: Apply them to the motor's A, B, and C three-phase winding voltages to power the motor.

[0064] S103: Sample the three-phase current i of the motor through the current sensor (ADC) a 、i b 、i c , through the abc / αβ and αβ / dq coordinate transformations in turn, the dq axis feedback current is obtained and Feedback current of dq axis system and Perform signal processing to obtain its high-frequency current component and

[0065] By and Multiply by the transformation matrix R(θ0) to transform the two high-frequency current components to the decoupled axis m * , which converts it to Figure 3 Medium m -q m shafting.

[0066] Since the injected signal is a mixed waveform, the current changes are inconsistent within each DSP operation time interval, so the obtained high-frequency current needs to be decoupled. Specifically, the absolute value of the high-frequency current under the decoupled shaft system is taken and divided by the absolute value of the amplitude of the injected high-frequency voltage corresponding to the current high-frequency current (the high-frequency voltage injected at the previous moment) to obtain the high-frequency current for rotor position estimation after decoupling. and

[0067] In the rotor position estimation of the phase-locked loop (PLL), the PI parameters are adjusted so that Converges to 0 (where k s is a coefficient related to the motor parameters), the rotor position can be accurately followed. and The high-frequency currents at two adjacent moments are and The difference.

[0068] right By performing integration processing, the angle and angular velocity of the rotor can be obtained; the angular velocity of the rotor is brought into the input given by the q-axis current After feedback current regulation, the real-time base frequency current is given, and then the entire control is completed.

[0069] In addition, it is important to note that after the rotor position estimation is completed, the inherent rotor estimation error must be compensated in combination with the motor parameters to achieve high-performance rotor position tracking.

[0070] In this embodiment, the high frequency mixed voltage signal u is injected into the d-axis of the observation axis system. dh Considering the cross-saturation effect of the synchronous reluctance motor, the high-frequency current caused by the high-frequency d-axis signal can be solved as:

[0071]

[0072] Since the inductance parameters of the synchronous reluctance motor are sensitive to the changes of the fundamental frequency current, they are expressed as a function of the fundamental frequency current, where u dh is the high-frequency voltage signal injected into the d-axis of the observation axis system, is the dq axis correction inductance, is the dq axis cross-coupling inductance, is the d-axis incremental inductance, is the high-frequency current of the dq axis system, is the fundamental frequency current of the dq axis system.

[0073] From the above current solution model, it can be found that high-frequency current response is generated in the dq axis system, so the motor torque can be calculated as:

[0074]

[0075] Where, is the apparent inductance of the dq axis system, p is the number of motor pole pairs, is the q-axis incremental inductance.

[0076] Therefore, it can be found that when a high-frequency signal is introduced, the high-frequency torque component of the motor is not only related to the first-order term of the high-frequency current, but also to the second-order term of the high-frequency current.

[0077] Under high-frequency signal injection, the electromagnetic vibration near the motor injected with the high-frequency signal is positively correlated with the amplitude of the high-frequency current, so the amplitude of the high-frequency current directly affects the electromagnetic vibration of the motor.

[0078] Therefore, based on the high-frequency dq shaft current characteristics under the injection of mixed signals in the observed shaft system and taking into account the compensation of the rotor position error, the sensorless drive of the synchronous reluctance motor with low high-frequency torque and low electromagnetic vibration at zero and low speed is realized.

[0079] Figure 1 (a) shows the voltage and triangular wave current generated when a square wave signal is injected; Figure 1(b) shows the schematic diagram of high-frequency voltage and high-frequency current generated when high-frequency mixed voltage signal is injected; combined with Figure 1 It can be seen that the hybrid voltage signal injected in this embodiment can produce lower current fluctuations than existing square wave injection techniques. Specifically, when the two injected voltages achieve volt-second balance, that is, when the maximum amplitude of the generated high-frequency current is equal, the current generated by the hybrid high-frequency voltage injection technique is always less than or equal to the high-frequency current generated by the square wave injection technique. Consequently, the fundamental component of the high-frequency current generated by the hybrid injection signal is lower than that generated by the square wave injection technique.

[0080] The detailed Fourier decomposition is given in Figure 2 As shown, Figure 2 A comparison of the Fourier decomposition of the current response to a high-frequency mixed voltage signal and a square wave voltage signal is given. It can be seen that although the mixed signal exhibits slightly higher components when compared to the third, fifth, and seventh harmonics, its amplitude is significantly lower than the fundamental amplitude, and its impact on torque noise and electromagnetic vibration is not as significant as the fundamental. Therefore, the fundamental component is the main noise frequency of concern.

[0081] Figure 4 The experimental test platform for the method of this embodiment is shown in Figure 1, where 1 is a synchronous reluctance motor, 2 is a vibration acceleration sensor, 3 is a torque-speed sensor, 4 is a magnetic powder brake, 5 is a tension controller, 6 is computer 1, 7 is a DASP analyzer, and 8 is computer 2. During the experimental test, the DC power supply was 514V, and the inverter CPU was an STM320F28335. The synchronous reluctance motor was connected to computer 1 via the inverter. High-frequency square wave and mixed waveform voltage injection techniques were applied to the motor to achieve sensorless control of the synchronous reluctance motor. The tension controller provided a constant current source for the magnetic powder brake, achieving constant torque. For data collection, current was transmitted to the CPU via the inverter's current sensor, and then to computer 1 via RS485 communication. The torque signal was directly output by the torque sensor. The electromagnetic vibration signal was acquired via the acceleration sensor, transmitted to the DASP analyzer, and processed by computer 2. The frequency of the high-frequency signal is 312.5 Hz, and the square wave voltage is 120 V. Based on the volt-second balance and mixed voltage expressions, the injection size of the high-frequency mixed voltage is determined.

[0082] Figure 5 A schematic diagram of the steady-state and dynamic test results of the motor under square wave injection is given; among them, Figure 5 (a) is the test result of 0RPM~50RPM, (b) is the test result of 50RPM~100RPM;

[0083] Figure 6 A schematic diagram of the steady-state and dynamic test results of the motor under mixed signal injection is given; among them, Figure 6 (a) is the test result of 0RPM~50RPM, (b) is the test result of 50RPM~100RPM;

[0084] contrast Figure 5 and Figure 6 It can be found that compared with the square wave injection method, the mixed signal injection method of this embodiment also shows better comprehensive performance and can realize sensorless control of the synchronous reluctance motor, verifying the feasibility and reliability of this method.

[0085] Figure 7 The Fourier decomposition results of the motor steady-state current test with mixed signal injection and square wave injection are given; among them, Figure 7 (a) in the figure is a low-speed condition of 50 RPM (revolutions per minute). Figure 7 (b) is a low-speed condition of 100 RPM (revolutions per minute); and the enlarged part near the injection frequency in the gray box is shown; Figures 8-10 Same here.

[0086] Figure 8 The energy spectrum analysis results of the motor steady-state current test with mixed signal injection and square wave injection are given; among them, Figure 8 (a) in the figure is a low-speed condition of 50 RPM (revolutions per minute). Figure 8 (b) in the figure is a low-speed operating condition of 100 RPM (revolutions per minute).

[0087] Depend on Figure 7 and Figure 8 It can be found that around 312.5Hz (f h ±f c ), the current noise of the mixed signal injection technology is smaller than that of the square wave injection. h ±f c ), the current noise of the mixed signal injection technique is larger than that of the square wave injection. Figure 2 The results of Fourier classification were consistent.

[0088] Figure 9 The Fourier transform results of the motor steady-state torque fluctuations with mixed signal injection and square wave injection are given; Figure 9 (a) in the figure is a low-speed condition of 50 RPM (revolutions per minute). Figure 9 (b) in the figure is a low-speed operating condition of 100 RPM (revolutions per minute).

[0089] Figure 10 The results of the motor steady-state torque fluctuation energy spectrum of mixed signal injection and square wave injection are given; among them, Figure 10 (a) in the figure is a low-speed condition of 50 RPM (revolutions per minute). Figure 10(b) in the figure is a low-speed operating condition of 100 RPM (revolutions per minute).

[0090] Depend on Figure 9 and Figure 10 It can be seen that there is high torque ripple near low frequencies, but this ripple is due to the inherent properties of the motor structure and experimental platform, not the injected high-frequency signal. However, around 312.5Hz and 625Hz, the torque ripple using mixed-signal injection is smaller than that using square-wave injection. These frequencies are caused by the linear and quadratic terms of the high-frequency current, respectively.

[0091] Figure 11 The electromagnetic vibration results of high-frequency square wave and mixed waveform voltage injection techniques were compared. It can be seen that around 312.5 Hz, the vibration acceleration of the mixed signal injection technique is significantly lower than that of square wave injection. However, around 937.5 Hz, the vibration acceleration of the mixed signal injection technique is greater than that of square wave injection. Although the mixed signal causes larger electromagnetic vibrations around 937.5 Hz, the vibration acceleration amplitude is smaller than that at 312.5 Hz. Overall, sensorless control using mixed signal injection achieves lower electromagnetic vibrations.

[0092] In summary, the mixed signal injection method of this embodiment not only shows good comprehensive performance and realizes sensorless control of the synchronous reluctance motor, but also shows better effects than the square wave injection method in terms of current noise, torque ripple and electromagnetic vibration. It can reduce the fundamental component of the high-frequency current in the motor circuit, realize the suppression of the current noise of the synchronous reluctance motor near the injection frequency, and further reduce the high-frequency torque ripple and electromagnetic vibration of the synchronous reluctance motor.

[0093] Example 2

[0094] In one or more embodiments, a sensorless control system for a synchronous reluctance motor with mixed signal injection is disclosed, comprising:

[0095] A signal injection module is used to inject a high-frequency mixed voltage signal into the d-axis of the observation axis system. The high-frequency mixed voltage signal is constructed by mathematically changing four sine waves, and the integral of the injected voltage within one cycle is 0;

[0096] The motor power supply module is used to perform dq / αβ transformation on the observed shaft voltage injected with the high-frequency mixed voltage signal and apply it to the motor A, B, and C three-phase winding voltages;

[0097] The current sampling module is used to sample the three-phase current of the motor and obtain the dq-axis high-frequency current of the observation axis system through coordinate transformation;

[0098] The rotor position estimation module is used to decouple the obtained high-frequency current and estimate the motor rotor position based on a phase-locked loop.

[0099] The specific implementation of each of the above modules is exactly the same as that in Example 1 and will not be described in detail.

[0100] Example 3

[0101] In one or more embodiments, a terminal device is disclosed, which includes a processor and a memory, wherein the processor is used to implement instructions; the memory is used to store multiple instructions, and the instructions are suitable for being loaded by the processor and executed by the sensorless control method of the synchronous reluctance motor with mixed signal injection described in Example 1.

[0102] It should be understood that in this embodiment, the processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), off-the-shelf field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0103] The memory may include a read-only memory and a random access memory, and provides instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0104] During implementation, each step of the above method may be completed by an integrated logic circuit of hardware in a processor or by instructions in the form of software.

[0105] Example 4

[0106] In one or more embodiments, a computer-readable storage medium is disclosed, which stores a plurality of instructions suitable for being loaded and executed by a processor of a terminal device to implement the sensorless control method for a synchronous reluctance motor with mixed signal injection described in the first embodiment.

[0107] Example 5

[0108] In one or more embodiments, a computer program product is disclosed, including a computer program / instruction, which, when executed by a processor, implements the sensorless control method for a synchronous reluctance motor with mixed signal injection described in the first embodiment.

[0109] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A sensorless control method for a synchronous reluctance motor using mixed signal injection, characterized in that: include: Inject a high-frequency mixed voltage signal into the d-axis of the observation axis system. The high-frequency mixed voltage signal is constructed by mathematically changing four sine waves, and the integral of the injected voltage within one cycle is 0. The observed shaft voltage injected with the high-frequency mixed voltage signal is transformed into dq / αβ and applied to the three-phase winding voltages of the motor A, B, and C; The three-phase current of the motor is sampled and the dq-axis high-frequency current of the observation axis system is obtained through coordinate transformation; The obtained high-frequency current is decoupled and the motor rotor position is estimated based on a phase-locked loop.

2. The sensorless control method for a synchronous reluctance motor with mixed signal injection according to claim 1, characterized in that: The high-frequency mixed voltage signal is specifically: Among them, u dh is the high-frequency mixed voltage signal injected into the d-axis of the observation axis system, U inj is the amplitude of the injected high-frequency mixed voltage signal, f is the frequency of the injected high-frequency mixed voltage signal, t is the time, T i is the period of injecting high frequency mixed voltage signal.

3. The sensorless control method for a synchronous reluctance motor with mixed signal injection according to claim 1, characterized in that: Taking into account the cross-saturation effect of the synchronous reluctance motor, the high-frequency current caused by the d-axis high-frequency mixed voltage signal is specifically: Among them, u dh is the high-frequency voltage signal injected into the d-axis of the observation axis system, is the dq axis correction inductance, is the dq axis cross-coupling inductance, is the d-axis incremental inductance, is the high-frequency current of the dq axis system, is the fundamental frequency current of the dq axis system.

4. The sensorless control method for a synchronous reluctance motor with mixed signal injection according to claim 1, characterized in that: After obtaining the motor rotor position estimate, the method further includes: compensating for inherent rotor estimation errors in combination with motor parameters.

5. The sensorless control method for a synchronous reluctance motor with mixed signal injection according to claim 1, characterized in that: The obtained high-frequency current is decoupled and the motor rotor position is estimated based on a phase-locked loop. Specifically: Multiplying the obtained high-frequency current by a transformation matrix to transform the high-frequency current from the observation axis system to the decoupled axis system; Take the absolute value of the converted high-frequency current and divide it by the absolute value of the injected high-frequency voltage amplitude corresponding to the current high-frequency current to obtain the dq axis high-frequency current for rotor position estimation after decoupling and By adjusting the PI parameters Converges to 0, achieving accurate tracking of the rotor position; Perform integration processing to obtain the angle and angular velocity of the rotor; where k s is the coefficient.

6. A sensorless control system for a synchronous reluctance motor with mixed signal injection, characterized in that: include: A signal injection module is used to inject a high-frequency mixed voltage signal into the d-axis of the observation axis system. The high-frequency mixed voltage signal is constructed by mathematically changing four sine waves, and the integral of the injected voltage within one cycle is 0; The motor power supply module is used to perform dq / αβ transformation on the observed shaft voltage injected with the high-frequency mixed voltage signal and apply it to the motor A, B, and C three-phase winding voltages; The current sampling module is used to sample the three-phase current of the motor and obtain the dq-axis high-frequency current of the observation axis system through coordinate transformation; The rotor position estimation module is used to decouple the obtained high-frequency current and estimate the motor rotor position based on a phase-locked loop.

7. A sensorless control system for a synchronous reluctance motor with mixed signal injection according to claim 6, characterized in that: The high-frequency mixed voltage signal is specifically: Among them, u dh is the high-frequency mixed voltage signal injected into the d-axis of the observation axis system, U inj is the amplitude of the injected high-frequency mixed voltage signal, f is the frequency of the injected high-frequency mixed voltage signal, t is the time, T i is the period of injecting high frequency mixed voltage signal.

8. A terminal device comprising a processor and a memory, wherein the processor is used to implement instructions; the memory is used to store multiple instructions, characterized in that: The instructions are suitable for being loaded by a processor and executing the sensorless control method for a synchronous reluctance motor with mixed signal injection according to any one of claims 1 to 5.

9. A computer-readable storage medium storing a plurality of instructions, characterized in that: The instructions are suitable for being loaded by a processor of a terminal device and executing the sensorless control method for a synchronous reluctance motor with mixed signal injection according to any one of claims 1 to 5.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the sensorless control method for a synchronous reluctance motor with mixed signal injection according to any one of claims 1 to 5 is implemented.

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