Method, device and system for estimating low-speed rotor position of an ac synchronous machine

Abstract

The application discloses a low-speed rotor position estimation method, device and system of an alternating current synchronous motor. The method steps of the application comprise: (1) injecting a rotating high-frequency voltage signal in an estimated synchronous rotating coordinate system to obtain a high-frequency current response in the estimated synchronous rotating coordinate system, calculating an amplitude expression thereof and observing rotor position information contained in the current amplitude; and (2) performing coordinate transformation on the high-frequency current response in the estimated synchronous rotating coordinate system, so that the amplitude expression of the transformed current contains a sine quantity of rotor position deviation information, combining a corresponding current amplitude extraction method to construct a phase-locked loop, and thus estimating the rotor position. Compared with an existing rotating high-frequency voltage injection method, the application can reduce rotor position estimation errors under influences of stator resistance, induced electromotive force, a filter, a PI current regulator and a digital control delay, and the method of the application can maintain high position estimation precision at different steady-state rotating speeds.

Description

Technical Field

[0001] This invention relates to a method for estimating the low-speed rotor position of an AC synchronous motor using the relationship between current response amplitudes, and belongs to the field of motor control. Background Technology

[0002] AC synchronous motors possess advantages such as high power factor, wide speed range, and fast dynamic response, and are widely used in military, defense, aviation, aerospace, and industrial fields. High-performance control of AC synchronous motors relies on accurate acquisition of the motor's rotor position. Currently, most low-speed rotor position estimation methods for AC synchronous motors are based on detecting changes in stator inductance caused by the salient pole effect of the motor. These methods can be broadly classified into two categories: pulse width modulation (PWM) excitation methods and high-frequency signal injection methods.

[0003] The earliest PWM excitation method was the indirect flux detection (INFORM) method using online reactance measurement. Its main principle is to measure the current response caused by voltage space vectors applied in different directions, and then estimate the rotor position based on the current response. Three-phase test voltage vectors are inserted into the zero-position portion of three consecutive PWM cycles, and equal and opposite three-phase voltage vectors are then inserted to cancel their influence on the fundamental wave control. To ensure the effectiveness of the INFORM method, a current derivative measurement needs to be performed in each of the three cycles. Modifying the voltage vectors of the PWM cycles can generate various types of PWM excitation methods, such as zero-sequence current derivative measurement (ZSCD) and zero-voltage vector injection (ZVVI). Compared to the INFORM method, ZSCD's test vectors are applied only briefly between normal PWM waveforms, resulting in better performance, but it requires special current derivative measurement sensors or complex algorithms. ZVVI requires inserting additional zero-voltage vectors between PWM cycles. Compared to ordinary PWM switching modes, to improve sampling accuracy, the period of the zero-voltage vector needs to be extended, leading to relatively large current fluctuations. The position estimation error is mainly determined by the accuracy of the sampled current and current derivative. Furthermore, by setting the inverter's modulation mode to sinusoidal pulse width modulation, the output can be equivalent to a rotating voltage signal injected into a two-phase stationary shaft system, and rotor position estimation can be achieved based on the current envelope of the carrier frequency.

[0004] There are two main methods for estimating rotor position: rotating high-frequency signal injection and pulsed high-frequency signal injection. Pulsed high-frequency signal injection can be further divided into pulsed sinusoidal signal injection and pulsed square wave signal injection, depending on the type of injected signal. Applying two-phase orthogonal high-frequency voltages to the two-phase stationary coordinate system of an AC synchronous motor allows the extraction of the negative-sequence component containing rotor position information from the high-frequency current response using either a coaxial low-pass filter (SFLF) or a coaxial high-pass filter (SFHF) algorithm. Alternatively, rotor position information can be calculated from the zero-sequence voltage, but this places additional demands on the hardware, requiring the construction of an impedance network to measure the zero-sequence voltage. The method using a coaxial high-pass filter algorithm to estimate rotor position does not require pre-estimation of rotor position information; it directly injects the high-frequency signal into the two-phase stationary coordinate system, resulting in good system stability. However, its disadvantages include a complex signal demodulation process, reduced dynamic performance due to the use of multiple filters, and reduced position estimation accuracy due to non-ideal factors such as system delay, resistance, cross-saturation, and inverter nonlinearity. Injecting a rotating high-frequency voltage into the estimated synchronous rotating coordinate system and using the product of the two-phase high-frequency current responses of the estimated synchronous rotating coordinate system to obtain the position deviation signal can improve the position estimation accuracy and simplify the signal processing process.

[0005] The main difference between the pulsed high-frequency signal injection method and the rotating high-frequency signal injection method lies in the form of signal injection. The rotating high-frequency injection method generally injects two-phase orthogonal high-frequency voltages into a two-phase coordinate system, while the pulsed high-frequency signal injection method injects a single-phase high-frequency voltage into a two-phase coordinate system. The pulsed sinusoidal voltage injection method uses current amplitude to demodulate the rotor position. Its advantages include high position estimation accuracy, less susceptibility to inverter nonlinearity, and applicability to both salient-pole and non-salient-pole motors. Disadvantages include changes in high-frequency impedance and other parameters altering the convergence point of the closed-loop system, affecting system stability, long convergence time, and a small stability range; careful selection of observer parameters is also necessary. Some scholars have analyzed the disadvantages of injecting high-frequency sinusoidal signals for d-axis estimation and proposed a position observation method that injects signals for q-axis estimation. The pulsed square wave voltage injection method increases the frequency of the injected signal to the switching frequency level, thus eliminating the need for a low-pass filter and improving system bandwidth. However, to ensure a high signal-to-noise ratio, this method requires increasing the amplitude of the injected voltage, which limits the utilization of the fundamental voltage. Furthermore, square wave signal injection introduces higher losses and noise. Compared to the positive and negative sequence components in the high-frequency current response, the zero-sequence component is less affected by inverter nonlinearity and current regulator. Extracting rotor position information from the zero-sequence component can improve the system's bandwidth and stability. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a method for estimating the low-speed rotor position of an AC synchronous motor using the relationship between current response amplitudes. A high-frequency rotating voltage signal is injected into the estimated synchronous rotating coordinate system of the motor to obtain the high-frequency current response in the estimated synchronous rotating coordinate system. The high-frequency current response in the estimated synchronous rotating coordinate system is then transformed to include a sinusoidal quantity containing rotor position deviation information in the transformed current amplitude expression. A phase-locked loop is constructed using a corresponding current amplitude extraction method to estimate the rotor position.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] This invention first proposes a method for estimating the low-speed rotor position of an AC synchronous motor, comprising the following steps:

[0009] S1. Inject two-phase orthogonal high-frequency voltage signals into the estimated synchronous rotating coordinate system of the AC synchronous motor. Considering the effects of non-ideal factors such as stator resistance, induced electromotive force, filter, PI current regulator and digital control delay, the high-frequency current response of the estimated synchronous rotating coordinate system is obtained.

[0010] S2. Calculate and estimate the high-frequency current response amplitude expression of the synchronous rotating coordinate system, observe the rotor position information, and make the transformed current amplitude expression include the sinusoidal quantity of rotor position deviation information through coordinate transformation.

[0011] S3. Extract the current amplitude, construct a position deviation signal in the form of a sine function, and obtain the estimated speed and estimated rotor position through a PI controller and integrator.

[0012] As a preferred embodiment of the method of the present invention, the high-frequency current response and amplitude expression after coordinate transformation are as follows:

[0013]

[0014] in, and They are respectively The current after π / 4 transformation of the shaft high-frequency current response. and They are respectively and The amplitude. Extract and Then, the rotor position deviation information is obtained through simple numerical calculations, and then a phase-locked loop is constructed to estimate the rotor position.

[0015] On the other hand, the present invention also proposes a low-speed rotor position estimation device for an AC synchronous motor, comprising:

[0016] A high-frequency voltage injection module is used to generate a high-frequency current response containing rotor position information;

[0017] The coordinate transformation module performs a π / 4 transformation on the estimated high-frequency current response in the synchronous rotating coordinate system, so that the transformed current contains a sinusoidal rotor position deviation signal.

[0018] The rotor position deviation information construction module extracts the current amplitude after π / 4 transformation and constructs rotor position deviation information through simple numerical calculations.

[0019] The phase-locked loop module uses a PI controller and a 1 / s integrator to converge the estimated rotor position to the actual rotor position by transmitting the rotor position deviation information.

[0020] The present invention also proposes an electronic system comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the method steps of the present invention.

[0021] Finally, the present invention also provides a computer-readable storage medium storing computer instructions for causing the computer to perform the steps of the method of the present invention.

[0022] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:

[0023] 1. This invention provides a novel method for estimating the low-speed rotor position of an AC synchronous motor. It utilizes the estimated current amplitude in the synchronous rotating coordinate system to construct a rotor position deviation signal and combines this with a phase-locked loop (PLL) to converge the estimated rotor position to the actual rotor position, simplifying the position calculation process and reducing the influence of non-ideal factors. Compared to the traditional rotating high-frequency voltage injection method, it reduces rotor position estimation errors caused by stator resistance, induced electromotive force, filters, PI current regulators, and digital control delays. The invented method maintains high position estimation accuracy at different steady-state speeds.

[0024] 2. The position estimation method provided by the present invention extracts rotor position information under the estimated synchronous rotating coordinate system, so that the frequencies of the positive and negative sequence currents are equal but opposite in sign, and can maintain the same and high position estimation accuracy at different speeds. Attached Figure Description

[0025] Figure 1 This is the frequency response diagram of a second-order Butterworth BPF.

[0026] Figure 2 High-frequency current phase shift curves on the d and q axes caused by the PI current regulator.

[0027] Figure 3 This is a system structure diagram of the low-speed rotor position estimation method proposed in this invention.

[0028] Figure 4 These are experimental comparison waveforms of the rotor position estimation method proposed in this invention and the SFHF method. Detailed Implementation

[0029] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0030] This invention proposes a low-speed rotor position estimation method utilizing the amplitude relationship of current response. For a complete high-frequency voltage model of an AC synchronous motor, two-phase orthogonal high-frequency voltages are injected into the estimated synchronous rotating coordinate system. The effects of the BPF, PI current regulator, and numerical control delay on the phase shift of the high-frequency current are considered to obtain the corresponding high-frequency current response.

[0031] For the high-frequency current response of the estimated synchronous rotating coordinate system, its amplitude expression is calculated, the rotor position information contained in the amplitude expression is observed, and the transformed current amplitude expression is made to contain a sinusoidal quantity containing rotor position deviation information through coordinate transformation.

[0032] For the high-frequency current response after coordinate transformation, a corresponding current amplitude extraction method is designed. Then, a position deviation signal in the form of a sine function is constructed, and the estimated speed and estimated rotor position are obtained through a PI controller and an integrator.

[0033] The following is a specific embodiment of the present invention, as detailed below:

[0034] First, a high-frequency rotating voltage signal is injected into the estimated synchronous rotating coordinate system of the motor. Considering the effects of stator resistance, induced electromotive force, filter, PI current regulator, and digital control delay, the high-frequency current response in the estimated synchronous rotating coordinate system is obtained. Its amplitude expression is calculated, and the rotor position information contained in the current amplitude is observed. The injected high-frequency rotating voltage signal is:

[0035]

[0036] in, To estimate the synchronous rotating coordinate system High-frequency voltage injected into the shaft, To estimate the synchronous rotating coordinate system High-frequency voltage injected into the shaft, U h ω represents the amplitude of the injected high-frequency voltage. h The frequency of the injected high-frequency voltage.

[0037] (1) Considering the stator resistance and induced electromotive force, the phase shifts caused by the positive and negative sequence high-frequency currents are respectively denoted as: and and and satisfy:

[0038]

[0039] Among them, R s L is the stator resistance. dh L qh The high-frequency inductances along the d and q axes are respectively, ω e ω is the electric angular velocity of the rotor.

[0040] (2) High-frequency current needs to be extracted using a bandpass filter (BPF). A BPF will produce different phase shifts for signals of different frequencies. Taking a high-frequency injection signal of 400Hz as an example, the frequency characteristics of its second-order Butterworth BPF are as follows: Figure 1 As shown. Let the phase shifts produced by the BPF for positive and negative sequence high-frequency currents with a frequency of 400Hz be respectively... and from Figure 1 It can be seen that the phase shift generated by the BPF has odd function characteristics, and it will produce an equal-value but opposite-sign phase delay for AC signals with the same frequency. Therefore...

[0041] (3) In the vector control system of AC synchronous motor, the current loop generally adopts a PI regulator. Taking the q-axis current loop as an example, the transfer function G between the injected q-axis high-frequency voltage and the high-frequency current response can be obtained. q (s) is:

[0042]

[0043] Where, k qp k qi These are the proportional and integral coefficients of the q-axis PI controller, respectively.

[0044] Substituting s = jω into G q (s), and its phase frequency characteristic is obtained as follows:

[0045]

[0046] in, This refers to the phase shift caused by the PI regulator in the q-axis current loop, and satisfy:

[0047]

[0048] Similarly, the phase shift caused by the PI regulator in the d-axis current loop is obtained. for:

[0049]

[0050] Where, k dp k di These are the proportional and integral coefficients of the d-axis PI controller, respectively.

[0051] The current loop parameters are tuned according to the internal model principle, that is:

[0052]

[0053] Where, ω c The current loop bandwidth is typically selected based on motor parameters and system requirements; here, it is set to 1000. The motor parameters used in this invention are shown in Table 1. Through numerical calculations, the high-frequency current phase shift curves of the d-axis and q-axis caused by the PI current regulator can be obtained, as shown below. Figure 2 As shown. From Figure 2 As can be seen, the phase shifts generated by the PI controller for the high-frequency currents along the d and q axes are almost equal, and the phase shifts generated by the PI current controller exhibit odd function characteristics, meaning that it will produce equal-value, opposite-sign phase shifts for AC signals of equal frequency. The phase shifts generated by the PI controller for the high-frequency currents along the d and q axes are consistent with the high-frequency current phase shifts in a two-phase stationary coordinate system, still satisfying the odd function characteristics. Let the phase shifts generated by the PI controller for the positive and negative high-frequency currents at 400Hz be respectively... and Then there is

[0054] Table 1 Parameters of AC Synchronous Motor

[0055]

[0056]

[0057] (4) Most motor controllers adopt digital control mode, and the delay in digital control will cause a phase shift in the current response. Taking regular sampling PWM as an example, the delay problem is discussed, where the sampling calculation time is T. d The switching period is T s To prevent the maximum duty cycle from being limited, it is generally not set to T. d Instead of updating the modulation signal immediately after the specified time, at the beginning of the (k+1)th carrier cycle, the control value of the previous cycle is written into the comparator register, and samples are taken for the calculation of the current cycle. Therefore, the control delay time caused at this time is T. s Simultaneously, the process of the modulated voltage being applied to the motor is equivalent to a zero-order hold, resulting in a PWM output delay of approximately 0.5T.s High-frequency signals require a delay of 1.5T. s Only after this can it function in the motor, which is equivalent to a phase lag angle δ, and can be expressed as:

[0058]

[0059] Among them, T h The period of the high-frequency injected signal, T h =2π / ω h .

[0060] When considering the influence of the above non-ideal factors, record These represent the effects of the above factors on... The total phase shift generated by the positive and negative sequence high-frequency currents in the coordinate system is as follows:

[0061]

[0062] Therefore, generated by two-phase quadrature high-frequency voltage signals The high-frequency current response of the shaft is:

[0063]

[0064] in, for High-frequency current response of the shaft, for High-frequency current response of the shaft, I ph I nh denoted by , respectively, are the positive-sequence and negative-sequence component amplitudes of the current response caused by the injected signal, and Δθ is the rotor position estimation error. θ is the actual value of the rotor position. This is the estimated rotor position. Simultaneously, calculation... The amplitude of the shaft high-frequency current is:

[0065]

[0066] in, They are respectively axis, The high-frequency current amplitude of the shaft. From the expression for the high-frequency current amplitude, it can be seen that the position deviation signal contained in the high-frequency current amplitude is in the form of cos(2Δθ). When cos(2Δθ)≈0, Δθ≠0, and the estimated rotor position cannot be obtained through the PI regulator and 1 / s integrator in the phase-locked loop.

[0067] Therefore, coordinate transformation is required to construct the position deviation signal in the form of a sine function. and After performing a π / 4 transformation, the transformed current and its corresponding amplitude are as follows:

[0068]

[0069] The method for constructing the position deviation signal in sinusoidal form, f(Δθ), is as follows:

[0070]

[0071] Therefore, the principle of the entire rotor position estimation includes three steps: (1) response to high-frequency current. and (2) Perform π / 4 transformation; (3) Extract the current amplitude and construct the position deviation signal in the form of sin(2Δθ); (4) Obtain the estimated rotational speed through a PI controller and a 1 / s integrator. and estimate rotor position The system structure block diagram of the low-speed rotor position estimation method for AC synchronous motors proposed in this invention is as follows: Figure 3 As shown.

[0072] To further illustrate the effectiveness of the proposed low-speed rotor position estimation method, the method was analyzed in an experiment. The AC synchronous motor parameters are shown in Table 1, with the injected high-frequency voltage signal having an amplitude of 20V and a frequency of 400Hz. Figure 4 These are the results of comparative experiments between the invented method and the SFHF method.

[0073] Figure 4 When the motor starts, the speed is accelerated from 0 to 200 r / min. At 3s, the given speed is adjusted to 300 r / min, at 6s, the given speed is adjusted to 400 r / min, and at 9s, the given speed is adjusted to 200 r / min. The acceleration and deceleration processes are given according to the ramp function. Figure 4 The results show that the estimated speeds of both methods can keep up with the actual speeds under accelerated, steady-state, and decelerated operation. The speed estimation error of the SFHF method under different steady-state speeds is 9.6 r / min to 11.7 r / min, while the speed estimation error of the invented rotor position estimation method using the current amplitude relationship under different steady-state speeds is 3.7 r / min to 5.2 r / min. Compared with the SFHF method, the invented rotor position estimation method using the current amplitude relationship has a better estimation effect on the actual speed.

[0074] at the same time Figure 4The rotor position estimation errors of the two methods are shown. The SFHF method has a position estimation error of 3.9° at 200 r / min, 8° at 300 r / min, and 13.7° at 400 r / min. The position estimation error is 3.9° when the motor speed decreases from 400 r / min to 200 r / min and stabilizes. The position estimation error varies with the rotational speed and shows an increasing trend. In contrast, the invented rotor position estimation method utilizing the current amplitude relationship has a position estimation error of 3.9° at 200 r / min. The position estimation error is -3.9° at 300 r / min, -4.1° at 400 r / min, and -3.8° at 200 r / min. The position estimation error is -4° when the motor speed is reduced from 400 r / min to 200 r / min and then stabilized. The position estimation error hardly changes with the speed, and the position estimation accuracy is higher than that of the SFHF algorithm. The position estimation error is reduced by 49% at 300 r / min and by 62% at 400 r / min.

[0075] Example 2:

[0076] This embodiment proposes a low-speed rotor position estimation device for an AC synchronous motor, comprising:

[0077] A high-frequency voltage injection module is used to generate a high-frequency current response containing rotor position information;

[0078] The coordinate transformation module performs a π / 4 transformation on the estimated high-frequency current response in the synchronous rotating coordinate system, so that the transformed current contains a sinusoidal rotor position deviation signal.

[0079] The rotor position deviation information construction module extracts the current amplitude after π / 4 transformation and constructs rotor position deviation information through simple numerical calculations.

[0080] The phase-locked loop module uses a PI controller and a 1 / s integrator to converge the estimated rotor position to the actual rotor position by transmitting the rotor position deviation information.

[0081] Example 3:

[0082] This embodiment proposes a computer-readable storage medium storing a computer program thereon. When the computer program is executed by a processor, it implements the steps of the method described in this invention, which will not be repeated here.

[0083] Example 4:

[0084] This embodiment also proposes an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor.

[0085] It should be noted that the processing flows of Embodiments 2 to 4 correspond to the specific steps of the method provided in the embodiments of the present invention, and have the corresponding functional modules and beneficial effects of the method. Technical details not described in detail in this embodiment can be found in the method provided in the embodiments of the present invention.

[0086] The program code used to implement the methods of this application may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0087] In the context of this application, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0088] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0089] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0090] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

[0091] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for estimating the low-speed rotor position of an AC synchronous motor, characterized in that, Including the following steps: S1. Inject two-phase orthogonal high-frequency voltage signals into the estimated synchronous rotating coordinate system of the AC synchronous motor. Considering the effects of stator resistance, induced electromotive force, filter, PI current regulator and digital control delay among non-ideal factors, the high-frequency current response of the estimated synchronous rotating coordinate system is obtained. S2. Calculate and estimate the high-frequency current response amplitude expression of the synchronous rotating coordinate system, observe the rotor position information, and make the transformed current amplitude expression include the sinusoidal quantity of rotor position deviation information through coordinate transformation. S3. Extract the current amplitude, construct a sinusoidal position deviation signal, and obtain the estimated speed and estimated rotor position through a PI controller and integrator. In step S2, the expression for the amplitude of the high-frequency current response of the synchronously rotating coordinate system is calculated. The amplitude of the shaft high-frequency current is: ， in, , They are respectively axis, The amplitude of the high-frequency current of the shaft, By transforming coordinates, the transformed current amplitude expression incorporates a sinusoidal quantity containing rotor position deviation information: the position deviation signal is constructed as a sinusoidal function. and conduct The transformation, the transformed current, and the corresponding current amplitude are as follows: ， ， In step S3, the method for constructing a sinusoidal position deviation signal is as follows: for: ， Then, the estimated rotational speed is obtained through a PI controller and a 1 / s integrator. and estimate rotor position ; The rotor position estimation error is: ， The simplified expression for rotor position error is: 。 2. The method according to claim 1, characterized in that, The two-phase quadrature high-frequency voltage signals mentioned in step S1 are: ， in, To estimate the synchronous rotating coordinate system High-frequency voltage injected into the shaft, To estimate the synchronous rotating coordinate system High-frequency voltage injected into the shaft, The amplitude of the injected high-frequency voltage. The frequency of the injected high-frequency voltage.

3. The method according to claim 2, characterized in that, The impact of non-ideal factors in step S1: (1) When considering the stator resistance and induced electromotive force, the phase shifts caused by the positive and negative sequence high-frequency currents are respectively denoted as: and ,and and satisfy: ， in, For stator resistance, , High-frequency inductors for the d and q axes, respectively. The electric angular velocity of the rotor; (2) Let the phase shifts generated by the bandpass filter BPF for the positive and negative sequence high-frequency currents be respectively and It will produce an equal-value, opposite-sign phase delay for AC signals of equal frequency, that is... ; (3) Transfer function between injected q-axis high-frequency voltage and high-frequency current response for: ， in, , These are the proportional and integral coefficients of the q-axis PI controller, respectively. Will Substitute into Its phase frequency characteristic is obtained as follows: ， in, This refers to the phase shift caused by the PI regulator in the q-axis current loop, and satisfy: ， Similarly, the phase shift caused by the PI regulator in the d-axis current loop is obtained. for: ， In the formula, , These are the proportional and integral coefficients of the d-axis PI controller, respectively. The current loop parameters are tuned according to the internal model principle, that is: in, Let be the current loop bandwidth, and let the phase shifts generated by the PI regulator for the positive and negative high-frequency currents be respectively... and Then there is ; (4) High-frequency signals require a delay Only after this can it function in the motor, which is equivalent to a phase lag angle. It is represented as: in, To control the delay time, The period of the high-frequency injected signal, .

4. The method according to claim 3, characterized in that, When considering the effects of stator resistance, induced electromotive force, BPF phase shift, PI current regulator phase shift, and digital control delay mentioned in step S1, record... , These represent the effects of the above factors on The total phase shift generated by the positive and negative sequence high-frequency currents in the coordinate system is as follows: ， Therefore, generated by two-phase quadrature high-frequency voltage signals The high-frequency current response of the shaft is: ， in, for High-frequency current response of the shaft, for High-frequency current response of the shaft, , These represent the positive-sequence and negative-sequence amplitudes of the current response induced by the injected signal, respectively. For rotor position estimation error, , This represents the actual rotor position. This is the estimated rotor position.

5. A low-speed rotor position estimation device for an AC synchronous motor that performs the method according to any one of claims 1-4, characterized in that, include: A high-frequency voltage injection module is used to generate a high-frequency current response containing rotor position information; The coordinate transformation module performs the estimated high-frequency current response in the synchronous rotating coordinate system. The transformation ensures that the transformed current contains a sinusoidal rotor position deviation signal; the transformed high-frequency current response and amplitude expression are as follows: ， ， in, and They are respectively , Shaft high-frequency current response The transformed current, and They are respectively and The amplitude is extracted. and Then, the rotor position deviation information is obtained through simple numerical calculations, and then a phase-locked loop is constructed to estimate the rotor position; Rotor position deviation information construction module, extract The transformed current amplitude is then used to construct rotor position deviation information through numerical calculations. The phase-locked loop module uses a PI controller and a 1 / s integrator to converge the estimated rotor position to the actual rotor position by transmitting the rotor position deviation information.

6. An electronic system comprising: At least one processor; And a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, characterized in that the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1-4.

7. A computer-readable storage medium storing computer instructions, characterized in that, The computer instructions are used to cause the computer to perform the method described in any one of claims 1-4.

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