Method, device and equipment for identifying initial phase of rotor of permanent magnet synchronous motor and storage medium
By injecting high-frequency voltage and opposite polarity current signal sequences into a high-power permanent magnet synchronous motor, and combining them with speed accumulation comparison, the safety hazards and accuracy problems of existing methods in high-power motors are solved, and the accurate identification of the rotor initial phase and the highly robust polarity judgment are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHONGQING JINKANG POWER NEW ENERGY CO LTD
- Filing Date
- 2025-12-22
- Publication Date
- 2026-04-28
AI Technical Summary
Existing methods for identifying the initial position of permanent magnet synchronous motor rotors are not suitable for high-power permanent magnet synchronous motors, especially when the initial position of the rotor is unknown. Injecting a large voltage poses a safety hazard, and the accuracy of existing methods is questionable when the resistance is low.
By injecting a high-frequency voltage signal into the direct axis, adjusting the quadrature axis current until the difference is less than a preset threshold, the estimated angle of the rotor position is determined. Then, a sequence of current signals with opposite polarity is injected, and the initial phase of the rotor position is determined by comparing the accumulated speeds. This avoids dependence on magnetic saturation effects and adopts an integral comparison strategy in the low-speed domain or under static conditions.
It achieves accurate identification of the initial phase of the rotor of a high-power motor, overcomes the problem of polarity misjudgment, ensures high robustness of polarity judgment in low signal-to-noise ratio environments, and improves safety and accuracy.
Smart Images
Figure CN121939873A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of motor control technology, and in particular to a method, apparatus, device, and storage medium for identifying the initial phase of a permanent magnet synchronous motor rotor. Background Technology
[0002] Existing methods for identifying the initial rotor position of permanent magnet synchronous motors (PMSMs) obtain a high-frequency injection position estimate by injecting a high-frequency voltage signal into the direct axis. Then, the magnitude of the direct axis fundamental frequency current is changed, and the polarity is determined based on the amplitude change of the high-frequency direct axis component, thus obtaining the rotor's initial position. This method requires changing the magnitude of the direct axis fundamental frequency current to increase the motor's magnetic field saturation effect. Polarity is distinguished by observing the nonlinear change in inductance caused by saturation. However, for high-power PMSMs, a large voltage is required to saturate the magnetic field. Injecting a large voltage when the rotor's initial position is unknown poses a safety hazard. Therefore, this method is not suitable for high-power PMSMs. Summary of the Invention
[0003] Based on this, a method, apparatus, device, and storage medium for identifying the initial phase of a permanent magnet synchronous motor rotor are provided, solving the problem that existing permanent magnet synchronous motor rotor position identification methods are not applicable to high-power permanent magnet synchronous motors.
[0004] In a first aspect, the present invention provides a method for identifying the initial phase of a permanent magnet synchronous motor rotor, the method comprising: By injecting a high-frequency voltage signal into the direct axis, the quadrature axis current is adjusted until the difference between the quadrature axis current and 0 is less than a preset threshold, thereby determining the estimated angle of the rotor position. Based on preset rules, a preset current signal sequence is injected into the quadrature axis; wherein, the preset current signal sequence includes at least a first current signal and a second current signal with opposite polarities, and the preset rules include that the injection time of the first current signal is a first time period, and the injection time of the second current signal is a second time period; Determine the first cumulative speed of the motor within a first set time period and the second cumulative speed within a second set time period; wherein the first set time period belongs to the first time period and the second set time period belongs to the second time period; By comparing the first cumulative speed with the second cumulative speed, it is determined whether to perform polarity correction on the estimated angle to obtain the initial phase of the rotor position.
[0005] Optionally, by injecting a high-frequency voltage signal into the direct axis and adjusting the quadrature axis current until the difference between the quadrature axis current and 0 is less than a preset threshold, the estimated angle of the rotor position is determined. This includes: injecting the high-frequency voltage signal into the direct axis; determining an angle error based on the responding quadrature axis current signal; wherein the angle error is the angle between the direct axis in the estimated coordinate system and the actual direct axis in the synchronous rotating coordinate system, the estimated coordinate system being constructed based on the synchronous rotating coordinate system; if the absolute value of the angle error is less than or equal to the preset threshold, it is determined that the difference between the quadrature axis current and 0 is less than the preset threshold, and the estimated angle of the rotor position is determined based on the angle error.
[0006] Optionally, determining the angle error based on the quadrature-axis current signal of the response includes: acquiring a sinusoidal signal of a set frequency, wherein the set frequency is the same as the frequency of the high-frequency voltage signal; multiplying the quadrature-axis current signal by the sinusoidal signal to obtain an error signal, wherein the error signal carries the angle error.
[0007] Optionally, determining the estimated angle of the rotor position based on the angle error includes: performing a low-pass filter on the error signal to obtain a filtered signal; performing proportional-integral adjustment on the filtered signal to obtain an estimated value of the rotor speed; and integrating the estimated value of the rotor speed to obtain the estimated angle of the rotor position.
[0008] Optionally, comparing the first cumulative rotational speed with the second cumulative rotational speed to determine whether to perform polarity correction on the estimated angle to obtain the initial phase of the rotor position includes: determining whether the first cumulative rotational speed is greater than the second cumulative rotational speed; if the first cumulative rotational speed is greater than the second cumulative rotational speed, then determining the estimated angle as the initial phase of the rotor position; if the first cumulative rotational speed is less than or equal to the second cumulative rotational speed, then performing polarity correction on the estimated angle to obtain the initial phase of the rotor position.
[0009] Optionally, injecting a preset current signal sequence into the quadrature axis includes: injecting the first current signal into the quadrature axis and starting timing; stopping the injection of the first current signal and injecting the second current signal into the quadrature axis in response to the timing value reaching the end time value of the first time period; stopping the injection of the second current signal in response to the timing value reaching the end time value of the second time period, wherein the duration of the second time period is greater than the duration of the first time period.
[0010] Optionally, the preset current signal sequence further includes a zero current signal; wherein the zero current signal is arranged between the first current signal and the second current signal, and the zero current signal is injected during a third time period.
[0011] Optionally, injecting a preset current signal sequence into the quadrature axis includes: injecting a first current signal into the quadrature axis and starting a timer; stopping the injection of the first current signal and injecting the zero current signal into the quadrature axis in response to the timer value reaching the end time value of the first time period; stopping the injection of the zero current signal and injecting the second current signal into the quadrature axis in response to the timer value reaching the end time value of the second time period; and stopping the injection of the second current signal in response to the timer value reaching the end time value of the second time period, wherein the duration of the second time period is greater than the duration of the first time period.
[0012] Optionally, the current value of each current signal in the preset current signal sequence is greater than a first preset value, wherein the first preset value is calculated based on the number of pole pairs of the motor, the flux linkage of the permanent magnet, the electromagnetic torque, the rotor inertial resistance, the internal bearing friction of the motor, and the internal air resistance of the motor.
[0013] Optionally, the duration of the first time period is a second preset value, wherein the second preset value is calculated based on the electromagnetic torque, the rotor inertial resistance, the internal bearing friction of the motor, the internal air resistance of the motor, the electric drive rotational inertia, the motor angular acceleration, and the maximum excitation speed.
[0014] Optionally, the first set time period and the first time period share a first end time, and the start time of the first set time period is n units earlier than the first end time; the second set time period and the second time period share a second end time, and the start time of the second set time period is n units earlier than the second end time; wherein, the value of n is 5% to 10% of the value corresponding to the first end time.
[0015] Secondly, the present invention provides a rotor initial phase identification device for a permanent magnet synchronous motor, the device comprising: The voltage injection module is used to adjust the quadrature axis current by injecting a high-frequency voltage signal into the direct axis until the difference between the quadrature axis current and 0 is less than a preset threshold, thereby determining the estimated angle of the rotor position. A current injection module is used to inject a preset current signal sequence into a cross-axis based on preset rules; wherein, the preset current signal sequence includes at least a first current signal and a second current signal arranged sequentially and with opposite polarities, and the preset rules include that the injection time of the first current signal is a first time period and the injection time of the second current signal is a second time period; The speed determination module is used to determine the first cumulative speed of the motor within a first set time period and the second cumulative speed within a second set time period; wherein the first set time period belongs to the first time period and the second set time period belongs to the second time period; The position determination module is used to compare the first cumulative rotational speed with the second cumulative rotational speed to determine whether to perform polarity correction on the estimated angle, and obtain the initial phase of the rotor position.
[0016] Optionally, the voltage injection module is further configured to inject the high-frequency voltage signal into the direct axis and determine the angle error based on the corresponding quadrature axis current signal; wherein the angle error is the angle between the direct axis in the estimated coordinate system and the actual direct axis in the synchronous rotating coordinate system, the estimated coordinate system being constructed based on the synchronous rotating coordinate system; if the absolute value of the angle error is less than or equal to the preset threshold, it is determined that the difference between the quadrature axis current and 0 is less than the preset threshold, and the estimated angle of the rotor position is determined based on the angle error.
[0017] Optionally, the voltage injection module is further configured to acquire a sinusoidal signal of a set frequency, wherein the set frequency is the same as the frequency of the high-frequency voltage signal; multiply the quadrature-axis current signal by the sinusoidal signal to obtain an error signal, wherein the error signal carries the angle error.
[0018] Optionally, the voltage injection module is further configured to perform low-pass filtering on the error signal to obtain a filtered signal; perform proportional-integral adjustment on the filtered signal to obtain an estimated value of the rotor speed; and integrate the estimated value of the rotor speed to obtain an estimated angle of the rotor position.
[0019] Optionally, the position determination module is further configured to determine whether the first cumulative rotational speed is greater than the second cumulative rotational speed; if the first cumulative rotational speed is greater than the second cumulative rotational speed, the estimated angle is determined as the initial phase of the rotor position; if the first cumulative rotational speed is less than or equal to the second cumulative rotational speed, the estimated angle is polarity corrected to obtain the initial phase of the rotor position.
[0020] Optionally, the current injection module is further configured to inject the first current signal into the quadrature axis and start timing; in response to the timing value reaching the end time value of the first time period, stop injecting the first current signal and inject the second current signal into the quadrature axis; in response to the timing value reaching the end time value of the second time period, stop injecting the second current signal, wherein the duration of the second time period is greater than the duration of the first time period.
[0021] Optionally, the preset current signal sequence further includes a zero current signal; wherein the zero current signal is arranged between the first current signal and the second current signal, and the zero current signal is injected during a third time period.
[0022] Optionally, the current injection module is further configured to inject the first current signal into the quadrature axis and start timing; in response to the timing value reaching the end time value of the first time period, stop injecting the first current signal and inject the zero current signal into the quadrature axis; in response to the timing value reaching the end time value of the third time period, stop injecting the zero current signal and inject the second current signal into the quadrature axis; in response to the timing value reaching the end time value of the second time period, stop injecting the second current signal, wherein the duration of the second time period is greater than the duration of the first time period.
[0023] Optionally, the current value of each current signal in the preset current signal sequence is greater than a first preset value, wherein the first preset value is calculated based on the number of pole pairs of the motor, the flux linkage of the permanent magnet, the electromagnetic torque, the rotor inertial resistance, the internal bearing friction of the motor, and the internal air resistance of the motor.
[0024] Optionally, the duration of the first time period is a second preset value, wherein the second preset value is calculated based on the electromagnetic torque, the rotor inertial resistance, the internal bearing friction of the motor, the internal air resistance of the motor, the electric drive rotational inertia, the motor angular acceleration, and the maximum excitation speed.
[0025] Optionally, the first set time period and the first time period share a first end time, and the start time of the first set time period is n units earlier than the first end time; the second set time period and the second time period share a second end time, and the start time of the second set time period is n units earlier than the second end time; wherein, the value of n is 5% to 10% of the value corresponding to the first end time.
[0026] Thirdly, the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the rotor initial phase identification method of the permanent magnet synchronous motor described in the first aspect.
[0027] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the method for initial phase identification of the rotor of a permanent magnet synchronous motor as described in the first aspect.
[0028] The aforementioned method, device, computer equipment, and storage medium for identifying the initial phase of a permanent magnet synchronous motor rotor obtain an estimated angle of rotor position by injecting a high-frequency voltage signal into the direct axis of the estimation coordinate system. Then, by injecting two current signals of opposite polarity and accumulating them with the motor's response speed, the polarity of the estimated angle is determined, thereby identifying the initial phase of the rotor position. This method does not rely on magnetic saturation effects, fundamentally overcoming the polarity misjudgment problem in the rotor initial phase identification process caused by the insignificant or high saturation point of magnetic saturation in high-power motors, ensuring the accuracy of initial phase identification for high-power motor rotors. Injecting two current signals of opposite polarity and accumulating them with the speed response is essentially an integral comparison strategy in the low-speed domain or static state. This strategy effectively smooths random disturbances and measurement noise, extracting the deterministic speed change trend caused by changes in current polarity, thus achieving highly robust polarity determination even in low signal-to-noise ratio environments. Attached Figure Description
[0029] Figure 1 This is a schematic diagram showing the d-axis located in the first quadrant in one embodiment; Figure 2 This is a schematic diagram showing the d-axis located in the fourth quadrant in one embodiment; Figure 3 This is a schematic diagram showing the d-axis located in the second quadrant in one embodiment; Figure 4 This is a schematic diagram showing the d-axis located in the third quadrant in one embodiment; Figure 5 This is a flowchart illustrating a method for identifying the initial phase of a permanent magnet synchronous motor rotor in one embodiment. Figure 6 This is a structural block diagram of a permanent magnet synchronous motor rotor initial phase identification device in one embodiment; Figure 7 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation
[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. The specific operational methods in the method embodiments can also be applied to the device embodiments or system embodiments. It should be noted that in the description of this invention, "multiple" is understood as "at least two". "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing together, or B existing alone. A connected to B can represent: A and B directly connected, or A and B connected through C. Furthermore, in the description of this invention, terms such as "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or order.
[0031] To facilitate understanding by those skilled in the art, the technical terms involved in this invention will first be explained.
[0032] The Clarke Transform, also known as the Clarke Conversion or αβ Transform, is a mathematical transformation that converts variables (such as voltage and current) in a three-phase AC system from a three-phase stationary coordinate system (a, b, c) to a two-phase stationary coordinate system (α, β).
[0033] The Park Transformation, also known as the dq Transformation, projects the three-phase currents (a, b, c) of the stator onto the direct axis (d-axis), the quadrature axis (q-axis), and the zero axis (0-axis) perpendicular to the dq plane, which rotate with the rotor. In other words, it transforms the abc coordinate system into the dq coordinate system.
[0034] In this invention, the acquisition, transmission, storage, and use of data all comply with the requirements of relevant national laws and regulations.
[0035] Before introducing the method for identifying the initial phase of a permanent magnet synchronous motor rotor provided by this invention, the technical background of this invention will be described in detail below for ease of understanding.
[0036] Existing methods for rotor position identification in permanent magnet synchronous motors (PMSMs) often determine rotor polarity by increasing the magnetic field saturation effect of the motor by changing the magnitude of the direct-axis fundamental frequency current. The polarity is then determined by observing the nonlinear change in inductance caused by saturation. However, for high-power PMSMs, this method requires injecting a large voltage to saturate the magnetic field. Injecting such a large voltage when the initial rotor position is unknown poses a safety hazard and is therefore unsuitable for high-power PMSMs. Other PMSM rotor position identification methods inject two sets of pulse signals into the estimated direct axis of the motor and compare the amplitudes of the two sets of feedback currents generated by these pulse signals to determine polarity. However, this approach may result in similar amplitudes of the two sets of feedback currents when the resistance is low, and it does not consider the influence of current detection errors, raising questions about its accuracy.
[0037] In view of this, this application provides a method, apparatus, computer equipment, and storage medium for identifying the initial phase of a permanent magnet synchronous motor rotor to solve the above problems.
[0038] To facilitate understanding, we will first provide a detailed introduction to the principles upon which this solution is based.
[0039] Permanent magnet synchronous motor synchronous rotating coordinate system ( The voltage equation (in axial coordinate system) is as follows: (1); (2); in, For stator resistance, , These are the d-axis inductance and the q-axis inductance, respectively. The angular velocity of the motor is angular velocity (rad / s). It is a permanent magnet flux chain. For d-axis current, For q-axis current, The voltage along the d-axis. This is the q-axis voltage. This is the d-axis current differential term. This is the q-axis current differential term.
[0040] At zero speed ( At this time, a high-frequency voltage signal is injected into the d-axis of the synchronously rotating coordinate system. It is 0, because Smaller (typically a few milliohms), so If this can be ignored, then after injecting a high-frequency voltage signal, the voltage equation of the synchronous rotating coordinate system becomes: (3); (4).
[0041] Taking the d-axis of the synchronously rotating coordinate system located in the first quadrant as an example, such as Figure 1 As shown, The axial coordinate system is a two-phase stationary coordinate system. The axis coordinate system is a true synchronous rotating coordinate system. The axial coordinate system is The estimated coordinate system of the axial coordinate system. The axis is the direct axis of the estimated synchronous rotating coordinate system. for shaft and The included angle of the shaft, which is also the estimated angle of the rotor's initial phase. For a true synchronous rotating coordinate system, the d-axis and The included angle of the shaft, which is also the true initial phase of the rotor. This is because during high-frequency voltage injection, the true angle... It is unknown; in fact, high-frequency voltage is injected into... Axis, estimated coordinate system ( (axis coordinate system) and the real synchronous rotating coordinate system ( Angular error between axial coordinate systems The following relationship exists: (5); Then estimate the coordinate system Axis and real synchronous rotating coordinate system The voltage and current between the axes have the following mapping relationship: (6); (7); Among them, matrix , , , They are respectively shaft voltage, shaft voltage, for shaft current differential term, for Differential term of shaft current.
[0042] First, perform simple transformations on equations (3) and (4) to obtain the following matrices: (8); Then, by combining equations (6), (7), and (8), we obtain the following matrix: (9).
[0043] To the estimated coordinate system Injecting a high-frequency voltage into the shaft yields: (10); Where B is the amplitude of the injected high-frequency voltage. The frequency of the injected high-frequency voltage.
[0044] Substituting equation (10) into equation (9) and performing simplification and integration, we obtain: (11); in For average inductance, , It is a half-differential inductor. , for shaft current, for Axis current.
[0045] right Perform amplitude modulation, and The error signal obtained by multiplication is expressed as: (12); The error signal includes high-frequency and low-frequency components. After low-pass filtering, the filtered signal is obtained, which is represented as follows: (13); The filtered signal is then approximated and linearized to obtain the following equation: (14).
[0046] When the above filtered signal is controlled to 0, the angle error... If it is 0, then and If they are equal, then the estimated position is the actual rotor position. Because the final modulation result is... If it is 0, then The axis must be with The axis is perpendicular, otherwise towards The high-frequency voltage injected by the shaft will The shaft generates a current component. shaft and There are two cases where the axis is perpendicular. The shaft is located at positive half axis or Negative half-shaft.
[0047] If the d-axis is located in the first quadrant (e.g.) Figure 1 (as shown) or the fourth quadrant (as shown) Figure 2 As shown), the estimated coordinate system can be adjusted by PI (Proportional-Integral) adjustment of the above filtered signal. Axial gradually producing Rotate in the direction with smaller shaft current component ( Figure 1 and Figure 2 The center rotates counterclockwise; if it rotates clockwise, then... Gradually increasing (which does not conform to the mechanism of PI adjustment) to make the estimated coordinate system converge to the true synchronously rotating coordinate system, so that... If the shaft coincides with the d-axis, the estimated rotor position does not require polarity correction. However, if the d-axis is located in the second quadrant (e.g., ...), ... Figure 3 (as shown) or the third quadrant (as shown) Figure 4 As shown), because During PI regulation The direction of decrease ( Figure 2 and Figure 4 Adjust by rotating the middle (clockwise). When the axis coincides with the negative half of the d-axis (the dashed part in the figure), It is also 0, so the final estimated coordinate system The axis will converge to the negative half of the d-axis of the real synchronous rotating coordinate system, therefore the estimated angle needs to be adjusted. The polarity is offset by 180°, and how to perform polarity identification will be explained in detail in the initial phase identification method for permanent magnet synchronous motor rotor provided in this application.
[0048] The technical solution provided in this application will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0049] Figure 5 This is a flowchart illustrating a method for identifying the initial phase of a permanent magnet synchronous motor rotor in one embodiment. This process can be executed by a permanent magnet synchronous motor rotor initial phase identification device, which can be implemented via software, hardware, or a combination of both. Figure 5 As shown, the process includes the following steps: S501, by injecting a high-frequency voltage signal into the direct axis, the quadrature axis current is adjusted until the difference between the quadrature axis current and 0 is less than a preset threshold, the estimated angle of the rotor position is determined, and the injection of the high-frequency voltage signal is stopped.
[0050] In one embodiment, a synchronous rotating coordinate system based on the motor ( Constructing an estimated coordinate system (axis coordinate system) In an estimated coordinate system (axis-axis coordinate system), a high-frequency voltage signal is injected onto the direct axis of the estimated coordinate system to obtain the corresponding quadrature-axis current signal. The specific process includes the following steps: S5011, acquire a cosine signal of a preset frequency. In some implementations, a cosine signal with a preset frequency can be generated by a calculation module. Cosine signals are simple in form, easy to analyze mathematically and process signals, and can improve subsequent demodulation efficiency.
[0051] S5012, converts the cosine signal of the preset frequency. With preset amplitude Multiply to form a pulsating high-frequency voltage signal .
[0052] S5013 will transmit the pulsed high-frequency voltage signal Inject the direct axis of the estimated coordinate system to obtain the three-phase current fed back by the motor.
[0053] S5014 performs coordinate transformation and bandpass filtering on the three-phase current to obtain the quadrature-axis current signal. In some implementations, the coordinate transformation includes Clark transform and Park transform. Bandpass filtering after Park transform can accurately separate the quadrature-axis current signal of a specific frequency.
[0054] In one embodiment, after obtaining the quadrature-axis current signal, the angle error and the estimated angle of the rotor position are determined based on the quadrature-axis current signal. The specific process includes the following steps: S5015, Obtain a sinusoidal signal of a preset frequency. In one embodiment, the sinusoidal signal of the preset frequency can be generated by a calculation module, and the preset frequency of the sinusoidal signal is the same as the preset frequency of the cosine signal generated in S5011. A sinusoidal signal is used to extract position error information from the amplitude of the quadrature-axis current signal. Using a sinusoidal signal with the same frequency as the cosine signal generated in S5011 is to avoid frequency deviation and improve the accuracy of the extracted position error information.
[0055] S5016 multiplies the quadrature-axis current signal with a sinusoidal signal of a preset frequency to obtain the error signal. The error signal carries the angular error of the rotor position. The angular error is the angle between the direct axis in the estimated coordinate system and the actual direct axis in the synchronous rotating coordinate system, that is, the error between the actual position and the estimated position.
[0056] S5017 performs a low-pass filter on the error signal to obtain the filtered signal. The low-pass filter removes high-frequency components from the error signal, preventing them from causing severe oscillations in the subsequent proportional-integral adjustment and thus hindering convergence.
[0057] S5018 performs proportional-integral (PI) regulation on the filtered signal to obtain an estimated value of the rotor speed.
[0058] S5019, the estimated rotor speed is integrated to obtain the estimated rotor position angle. In some embodiments, the estimated rotor position angle is generated by inputting the PI-regulated signal into the integration module.
[0059] In one embodiment, the absolute value of the angle error is determined to be less than or equal to a preset threshold by real-time detection of the output filtered signal, thereby determining whether the difference between the quadrature-axis current and 0 is less than the preset threshold. Because the error signal output in S5016 also includes high-frequency components, the angle error cannot be directly detected. However, after low-pass filtering, the high-frequency components are filtered out, and the resulting filtered signal is proportional to the angle error (for example,...). , For filtered signals, For gain, Since the angle error is calculated based on the magnitude of the filtered signal, it can be determined whether the angle error is less than or equal to a preset threshold. When the magnitude of the filtered signal is close to 0, the absolute value of the angle error is also close to 0, meaning the quadrature-axis current is close to 0. When the difference between the quadrature-axis current and 0 is less than the preset threshold, the injection of the high-frequency voltage signal is stopped. Based on the filtered signal at this time, the estimated angle of the rotor position is determined, this estimated angle is latched, and a preset current signal sequence is injected into the quadrature axis of the estimated coordinate system. It should be noted that injecting the preset current signal sequence into the quadrature axis is for subsequent polarity determination; the specific determination process will be described in detail in subsequent steps.
[0060] S502, based on preset rules, injects a preset current signal sequence into the quadrature axis.
[0061] In one embodiment, the injected preset current signal sequence includes a first current signal and a second current signal arranged sequentially, with opposite polarities. For example, the first current signal is a positive current signal, and the second current signal is a negative current signal. The preset rules include that the first current signal is injected during a first time period, such as [0, T1], and the second current signal is injected during a second time period, such as [0, T2]. In some embodiments, the step of sequentially injecting the first current signal and the second current signal into the intersection axis of the estimated coordinate system is as follows: S5021, a first current signal is injected into the quadrature axis of the estimated coordinate system, and timing begins. In some embodiments, timing begins when the injection of high-frequency voltage stops and the injection of the first current signal into the quadrature axis begins. The timing method can be a timer or a global counter. This application embodiment uses a timer as an example for explanation, but there are no specific limitations on the timing method.
[0062] S5022, in response to the timing value reaching the end time value of the first time period, the injection of the first current signal is stopped, and the second current signal is injected into the quadrature axis. For example, during the time period [0, T1] when the timer value is in the range of [0, T1], the first current signal is continuously injected into the quadrature axis, and when the value reaches T1, the injection of the first current signal into the quadrature axis is stopped, and the injection of the second current signal is switched.
[0063] S5023, in response to the timing value reaching the end time value of the second time period, the injection of the second current signal is stopped. For example, while the timer value is within the time period [T1, T2], the second current signal is continuously injected into the quadrature shaft, and when the value reaches T2, the injection of the second current signal is stopped. In one embodiment, the duration of the second time period for injecting the second current signal is longer than the duration of the first time period for injecting the first current signal. This is because when the first current signal is injected, the motor generates torque, thereby changing its speed. When the second current signal is injected, the torque direction is reversed. Compared to the first time period, the motor speed undergoes a larger range of dynamic adjustment. Setting the duration of the second time period to be longer than the duration of the first time period ensures that the motor speed has sufficient time to reach a new steady state during the second current signal injection phase, thereby ensuring the accuracy and reliability of the subsequently acquired speed data.
[0064] In one embodiment, the preset current signal sequence further includes a zero current signal, which is positioned between the first and second current signals; that is, the zero current signal is injected before the second current signal is injected into the intersection axis of the estimated coordinate system. The preset rule also includes that the injection time of the zero current signal is a third time period. In some embodiments, the steps of sequentially injecting the first current signal, the zero current signal, and the second current signal into the intersection axis of the estimated coordinate system are as follows: S5021', inject the first current signal into the intersection axis of the estimated coordinate system and start timing.
[0065] S5022', in response to the timing value reaching the end time value of the first time period, stops injecting the first current signal and injects a zero current signal into the quadrature axis. For example, during the time period [0, T1], the first current signal is continuously injected into the quadrature axis. When the value reaches T1, the injection of the first current signal into the quadrature axis stops, and a zero current signal is injected instead. Injecting a zero current signal allows the motor to return to a zero-torque reference state before applying a reverse second current signal. The motor speed gradually returns to zero due to frictional resistance, etc., thus greatly reducing the dynamic interference (such as back EMF changes and d-axis current coupling) caused by directly injecting the second current signal after the first current signal. This further improves the accuracy and reliability of the subsequently acquired speed data and avoids the overcurrent risk caused by directly injecting the second current signal after the first current signal, improving system safety.
[0066] S5023', in response to the timing value reaching the end time value of the third time period, stops injecting the zero current signal and injects a second current signal into the quadrature axis. For example, while the timer value is within the time period [T1, T2], where [T1, T2] is the set third time period for injecting the zero current signal, the zero current signal is continuously injected into the quadrature axis. When the value reaches T2, the injection of the zero current signal stops and switches to the injection of the second current signal.
[0067] In step S5024', in response to the timing value reaching the end time value of the second time period, the injection of the second current signal is stopped. For example, while the counter value is within the time period [T2, T3], where [T2, T3] is the set second time period for injecting the second current signal, the second current signal is continuously injected until the value reaches T3, at which point the injection of the second current signal stops. In some embodiments, the duration of the second time period for injecting the second current signal is longer than the duration of the first time period for injecting the first current signal, and the duration of the third time period for injecting zero current signal can be equal to or greater than the duration of the first time period.
[0068] In one embodiment, the current value corresponding to each current signal in the aforementioned preset current signal sequence must be greater than a first preset value; that is, the current values of the first current signal, the zero current signal, and the second current signal must all be greater than the first preset value. Injecting a current signal into the quadrature axis of the estimated coordinate system will generate a corresponding electromagnetic torque. This torque must overcome the rotor inertial resistance, the internal bearing friction, and the internal air resistance of the motor to cause a change in motor speed. Therefore, the first preset value can be calculated based on the electromagnetic torque, rotor inertial resistance, internal bearing friction, and internal air resistance. These parameters can be obtained through theoretical calculations or by testing the no-load loss of the motor using a dynamometer. The calculation process for the first preset value is as follows: According to the electromagnetic torque formula of a permanent magnet synchronous motor: (15); in, For electromagnetic torque, This represents the number of pole pairs of the motor. It is a permanent magnet flux chain. It is the q-axis inductance. For d-axis inductance, For d-axis current, This refers to the current injected into the q-axis that needs to be determined.
[0069] As can be seen from the foregoing embodiments, the d-axis current When the value is 0, the electromagnetic torque formula becomes: (16); Current injected into the q-axis The generated electromagnetic torque should be greater than the sum of the rotor inertial resistance, the internal bearing friction of the motor, and the internal air resistance of the motor. ,Right now: (17); The result is obtained from equation (17): (18).
[0070] That is, the first preset value is The current value of the current signal injected into the q-axis should be greater than In practical applications, this current should not be too large to avoid causing excessive vibration in the electric drive system. The specific value can be tested and adjusted during actual operation.
[0071] In one embodiment, the duration of the current signal injected into the q-axis also needs to meet requirements, namely, the durations of the first, second, and third time periods need to be limited. This is because if the injected current signal duration is too short, it is insufficient to cause the motor to rotate, or the resulting speed fluctuations will lead to inaccurate detection; if the injected current signal duration is too long, it will affect the overall detection time and cause the motor speed to be too high, resulting in a slower return to zero speed when zero current and negative current are input, leading to misjudgments during the negative current injection phase, thus affecting the final detection result. Therefore, the duration of the injected current signal can be determined based on electromagnetic torque, rotor inertial resistance, internal bearing friction, internal air resistance, electric drive moment of inertia, motor angular acceleration, and motor speed. Specifically, the duration of the first time period is set to a second preset value, and the process for determining the second preset value is as follows: Assume the maximum excitation speed generated after the first current signal is injected into the q-axis is ( Based on experience, it can be preset to 10 (the specific value can be determined during testing). Then, according to Newton's second law, the angular acceleration of the motor... for: (19); in, This represents the moment of inertia of the electric drive.
[0072] (20); in, This is the end time value of the first time period.
[0073] Substituting equations (16) and (19) into equation (20), we get: (twenty one); The second preset value is The duration of the first time period can be set to .
[0074] In some implementations, the duration of the third time period for injecting the zero-current signal can be set to be equal to the duration of the first time period, and the duration of the second time period for injecting the second current signal must be greater than the duration of the first time period. For example, the first time period for injecting the first current signal is represented as [0, ... The third time period during which a zero-current signal is injected is represented as [ , The second time period of injecting the second current signal is represented as [ , ],but hour, Designed for , Designed for The specific value can be adjusted adaptively based on the specific test results, and this application does not impose any restrictions.
[0075] S503, determine the first cumulative speed of the motor in a first set time period and the second cumulative speed in a second set time period.
[0076] In one embodiment, a first set time period belongs to a first time period, and the first set time period and the first time period share a first end time. The start time of the first set time period is n units earlier than the first end time. For example, if the first time period is represented as [0, T1], then the first set time period is [T1-n, T1]. A second set time period belongs to a second time period, and the second set time period and the second time period share a second end time. The start time of the second set time period is n units earlier than the second end time. For example, if the second time period is represented as [T2, T3], then the second set time period is [T3-n, T3].
[0077] Setting the first set time period for acquiring motor speed to the last n units of the first time period and the second set time period to the last n units of the second time period is to acquire the speed after the motor torque tends to stabilize after the current is injected into the q-axis for a period of time. This results in higher accuracy and reliability of the acquired speed, thereby improving the accuracy of polarity determination when determining rotor polarity through speed in the future.
[0078] The first and second cumulative speeds are obtained by summing the speeds at each sampling time within a corresponding set time period. In some embodiments, the motor speed is detected in real time throughout the entire process of injecting a current signal into the quadrature axis of the estimated coordinate system. At each unit time of the first set time period, the corresponding motor speed is extracted, for a total of n motor speeds, and these n motor speeds are summed to obtain the first cumulative speed. At each unit time of the second set time period, the corresponding motor speed is extracted, also for n motor speeds, and these n motor speeds are summed to obtain the second cumulative speed.
[0079] S504, compare the first accumulated speed with the second accumulated speed to determine whether to perform polarity correction on the estimated angle, and obtain the initial phase of the rotor position.
[0080] The rotor polarity of the motor is determined by comparing the magnitudes of a first accumulated speed and a second accumulated speed. In some implementations, it is determined whether the first accumulated speed is greater than the second accumulated speed.
[0081] If the first cumulative speed is greater than the second cumulative speed, then the estimated angle is determined as the initial phase of the rotor position. The fact that the first cumulative speed is greater than the second cumulative speed means that the estimated angle of the current rotor position corresponds to the direction of the d-axis (magnetic field axis) of the estimated coordinate system, which is consistent with the direction of the rotor's true north pole (N pole, i.e., the true positive direction of the d-axis). Therefore, the estimated angle is the initial phase of the true rotor position.
[0082] If the first cumulative speed is less than or equal to the second cumulative speed, the estimated angle is corrected to obtain the initial phase of the rotor position. If the first cumulative speed is less than or equal to the second cumulative speed, it means that the d-axis direction of the estimated coordinate system corresponding to the estimated angle of the current rotor position actually points towards the south pole (S pole) of the rotor. In this case, the estimated angle needs to be corrected (+180°) to obtain the initial phase of the true rotor position.
[0083] It should be understood that, although Figure 5 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 5 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.
[0084] In one embodiment, such as Figure 6 As shown, a rotor initial phase identification device for a permanent magnet synchronous motor is provided, comprising: The voltage injection module is used to adjust the quadrature axis current by injecting a high-frequency voltage signal into the direct axis until the difference between the quadrature axis current and 0 is less than a preset threshold, thereby determining the estimated angle of the rotor position. A current injection module is used to inject a preset current signal sequence into the quadrature axis based on preset rules; wherein, the preset current signal sequence includes at least a first current signal and a second current signal arranged in sequence and having opposite polarities, and the preset rules include that the injection time of the first current signal is a first time period and the injection time of the second current signal is a second time period; The speed determination module is used to determine the first cumulative speed of the motor within a first set time period and the second cumulative speed within a second set time period; wherein the first set time period belongs to the first time period and the second set time period belongs to the second time period; The position determination module is used to compare the first cumulative rotational speed with the second cumulative rotational speed to determine whether to perform polarity correction on the estimated angle, and obtain the initial phase of the rotor position.
[0085] Specific limitations regarding the initial phase identification device for permanent magnet synchronous motor rotors can be found in the limitations of the initial phase identification method for permanent magnet synchronous motor rotors mentioned above, and will not be repeated here. Each module in the aforementioned initial phase identification device for permanent magnet synchronous motor rotors can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in a computer device, or stored in software in the memory of a computer device, so that the processor can call and execute the operations corresponding to each module.
[0086] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 7As shown, the computer device includes a processor, memory, network interface, and database connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The database stores initial phase identification data for the permanent magnet synchronous motor rotor. The network interface communicates with external terminals via a network. When executed by the processor, the computer program implements a method for initial phase identification of a permanent magnet synchronous motor rotor. The display screen can be an LCD screen or an e-ink display screen. The input device can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device casing, or an external keyboard, touchpad, or mouse.
[0087] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present invention and does not constitute a limitation on the computer device to which the present invention is applied. A specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.
[0088] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any step of the method for initial phase identification of the rotor of a permanent magnet synchronous motor described above.
[0089] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements any step of the method for initial phase identification of the rotor of a permanent magnet synchronous motor described above.
[0090] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.
[0091] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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, they should be considered to be within the scope of this specification.
[0092] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.
Claims
1. A method for identifying the initial phase of a permanent magnet synchronous motor rotor, characterized in that, The method includes: By injecting a high-frequency voltage signal into the direct axis, the quadrature axis current is adjusted until the difference between the quadrature axis current and 0 is less than a preset threshold, thereby determining the estimated angle of the rotor position. Based on preset rules, a preset current signal sequence is injected into the quadrature axis; wherein, the preset current signal sequence includes at least a first current signal and a second current signal with opposite polarities, and the preset rules include that the injection time of the first current signal is a first time period, and the injection time of the second current signal is a second time period; Determine the first cumulative speed of the motor within a first set time period and the second cumulative speed within a second set time period; wherein the first set time period belongs to the first time period and the second set time period belongs to the second time period; By comparing the first cumulative speed with the second cumulative speed, it is determined whether to perform polarity correction on the estimated angle to obtain the initial phase of the rotor position.
2. The method according to claim 1, characterized in that, By injecting a high-frequency voltage signal into the direct axis, the quadrature axis current is adjusted until the difference between the quadrature axis current and 0 is less than a preset threshold, thereby determining the estimated angle of the rotor position, including: The high-frequency voltage signal is injected into the direct axis, and the angle error is determined based on the corresponding quadrature axis current signal; wherein, the angle error is the angle between the direct axis in the estimated coordinate system and the actual direct axis in the synchronous rotating coordinate system, and the estimated coordinate system is constructed based on the synchronous rotating coordinate system; If the absolute value of the angle error is less than or equal to the preset threshold, then it is determined that the difference between the quadrature axis current and 0 is less than the preset threshold, and the estimated angle of the rotor position is determined based on the angle error.
3. The method according to claim 2, characterized in that, The angle error is determined based on the response-based quadrature-axis current signal, including: Obtain a sinusoidal signal with a set frequency, wherein the set frequency is the same as the frequency of the high-frequency voltage signal; The quadrature-axis current signal is multiplied by the sine signal to obtain an error signal, wherein the error signal carries the angle error.
4. The method according to claim 3, characterized in that, The estimated angle for determining the rotor position based on the angle error includes: The error signal is low-pass filtered to obtain the filtered signal; The filtered signal is subjected to proportional-integral adjustment to obtain an estimated value of the rotor speed; Integrating the estimated rotor speed, the estimated rotor position angle is obtained.
5. The method according to any one of claims 1 to 4, characterized in that, The step of comparing the first cumulative rotational speed with the second cumulative rotational speed to determine whether to perform polarity correction on the estimated angle to obtain the initial phase of the rotor position includes: Determine whether the first cumulative speed is greater than the second cumulative speed; If the first cumulative speed is greater than the second cumulative speed, then the estimated angle is determined to be the initial phase of the rotor position; If the first cumulative speed is less than or equal to the second cumulative speed, then the estimated angle is polarity corrected to obtain the initial phase of the rotor position.
6. The method according to claim 1, characterized in that, The injection of a preset current signal sequence into the quadrature axis includes: Inject the first current signal into the cross-axis and start timing; In response to the timing value reaching the end time value of the first time period, the injection of the first current signal is stopped, and the second current signal is injected into the cross-axis; In response to the timing value reaching the end time value of the second time period, the injection of the second current signal is stopped, wherein the duration of the second time period is greater than the duration of the first time period.
7. The method according to claim 1, characterized in that, The preset current signal sequence further includes a zero current signal; wherein the zero current signal is arranged between the first current signal and the second current signal, and the zero current signal is injected during a third time period.
8. The method according to claim 7, characterized in that, The injection of a preset current signal sequence into the quadrature axis includes: Inject the first current signal into the cross-axis and start timing; In response to the timing value reaching the end time value of the first time period, the injection of the first current signal is stopped, and the zero current signal is injected into the quadrature axis; In response to the timing value reaching the end time value of the third time period, the injection of the zero current signal is stopped, and the second current signal is injected into the quadrature axis; In response to the timing value reaching the end time value of the second time period, the injection of the second current signal is stopped, wherein the duration of the second time period is greater than the duration of the first time period.
9. The method according to claim 1, characterized in that, The current value of each current signal in the preset current signal sequence is greater than a first preset value, wherein the first preset value is calculated based on the number of pole pairs of the motor, the flux linkage of the permanent magnet, the electromagnetic torque, the rotor inertial resistance, the internal bearing friction of the motor, and the internal air resistance of the motor.
10. The method according to claim 9, characterized in that, The duration of the first time period is a second preset value, which is calculated based on the electromagnetic torque, the rotor inertial resistance, the internal bearing friction of the motor, the internal air resistance of the motor, the electric drive rotational inertia, the motor angular acceleration, and the maximum excitation speed.
11. The method according to claim 1, characterized in that, The first set time period and the first time period share a first end time, and the start time of the first set time period is n units earlier than the first end time; The second set time period and the second set time period share a second end time, and the start time of the second set time period is n units earlier than the second end time; Wherein, the value of n is 5% to 10% of the value corresponding to the first endpoint time.
12. A rotor initial phase identification device for a permanent magnet synchronous motor, characterized in that, The device includes: The voltage injection module is used to adjust the quadrature axis current by injecting a high-frequency voltage signal into the direct axis until the difference between the quadrature axis current and 0 is less than a preset threshold, thereby determining the estimated angle of the rotor position. A current injection module is used to inject a preset current signal sequence into a cross-axis based on preset rules; wherein, the preset current signal sequence includes at least a first current signal and a second current signal arranged sequentially and with opposite polarities, and the preset rules include that the injection time of the first current signal is a first time period and the injection time of the second current signal is a second time period; The speed determination module is used to determine the first cumulative speed of the motor within a first set time period and the second cumulative speed within a second set time period; wherein the first set time period belongs to the first time period and the second set time period belongs to the second time period; The position determination module is used to compare the first cumulative rotational speed with the second cumulative rotational speed to determine whether to perform polarity correction on the estimated angle, and obtain the initial phase of the rotor position.
13. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1 to 11.
14. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 11.