Motor position sensorless control method and system

Abstract

The invention discloses a motor position sensorless control method and system. The method comprises the following steps: acquiring multiphase current of a motor through a current detection module; performing synchronous rotation coordinate transformation on the multi-phase current, injecting a high-frequency injection signal, acquiring a first current signal # imgabs1 # of a # imgabs0 # axis in an estimated synchronous rotation coordinate system, and performing filtering processing on the first current signal # imgabs2 # through a first generalized second-order integrator to obtain a second current signal # imgabs2 # of a # imgabs0 # axis; a high-frequency current signal # imgabs4 # of the # imgabs3 # axis is obtained, the high-frequency current signal # imgabs5 # and (-sin omega ht) are multiplied to obtain a current modulation signal # imgabs7 # of the # imgabs6 # axis, and omega h is the frequency of the high-frequency injection signal; and carrying out filtering processing on the current modulation signal # imgabs8 # through a second generalized second-order integrator to obtain a low-frequency current component containing rotor position information. According to the technical scheme provided by the invention, the estimation precision of the rotor position can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet synchronous motors, and in particular to a motor position sensorless control method and system. Background Art

[0002] Permanent Magnet Synchronous Motor (PMSM) has the advantages of simple structure, high power factor and small size, and is widely used in industrial manufacturing, household appliances and other fields.

[0003] The traditional control strategy of PMSM uses mechanical encoders to obtain rotor position information, which increases the manufacturing cost of the motor and reduces reliability and durability. Now, the PMSM position sensorless control strategy is mostly used. By collecting current and voltage variables related to speed, the rotor position and speed information are estimated to replace the mechanical encoder. It has the advantages of high reliability and strong environmental adaptability, so it has a good application prospect.

[0004] However, it is difficult to estimate the rotor position of a sensorless motor during low-speed operation of an existing PMSM, so starting a sensorless motor has always been a difficult problem. Summary of the invention

[0005] The embodiments of the present invention provide a motor position sensorless control method and system to improve the estimation accuracy of the rotor position.

[0006] In a first aspect, an embodiment of the present invention provides a motor position sensorless control method, comprising:

[0007] Acquire the multi-phase current of the motor through the current detection module;

[0008] The multiphase current is subjected to synchronous rotating coordinate transformation, and a high-frequency injection signal is injected to obtain an estimated synchronous rotating coordinate system. The first current signal of the axis

[0009] The first current signal The filtering process is performed by the first generalized second-order integrator to obtain the High frequency current signal of the shaft

[0010] The high frequency current signal and (-sinω h t) multiplied by Axis current modulation signal The ω h is the frequency of the high-frequency injection signal;

[0011] The current modulation signal The low-frequency current component containing the rotor position information is obtained by filtering through the second generalized second-order integrator.

[0012] In a second aspect, an embodiment of the present invention further provides a motor position sensorless control system, which is used to execute the motor position sensorless control method provided by any embodiment of the present invention, including:

[0013] A current detection module is used to obtain the multi-phase current of the motor;

[0014] A coordinate conversion module, used for performing synchronous rotation coordinate conversion on the multi-phase current;

[0015] The high frequency injection module is used to inject the high frequency injection signal into the estimated synchronous rotating coordinate system. axis;

[0016] The first generalized second-order integrator is used to estimate the synchronously rotating coordinate system The first current signal of the axis Get the High frequency current signal of the shaft

[0017] A modulation module is electrically connected to the output end of the first generalized second-order integrator, and is used to convert the high-frequency current signal and (-sinω h t) are multiplied to obtain the Axis current modulation signal The ω h is the frequency of the high-frequency injection signal;

[0018] The second generalized second-order integrator is used to modulate the current signal Filtering is performed to obtain the low-frequency current component containing the rotor position information.

[0019] In the present invention, the rotor position of the motor when running at low speed is obtained by combining a two-stage generalized second-order integrator with a high-frequency injection signal. Specifically, in the position sensorless control process of the PMSM, the multi-phase current of the motor is obtained by the current detection module and transformed into a synchronous rotating coordinate system. After injecting a high-frequency injection signal into the estimated synchronous rotating coordinate system, The first current signal of the axis Transmitted to the first generalized second-order integrator to extract the high-frequency current signal The high-frequency current signal at the output of the first generalized second-order integrator and (-sinω h t) multiply to form Axis current modulation signal Then the current modulation signal The input is sent to the second generalized second-order integrator for low-pass filtering to obtain the low-frequency current component of the rotor position information. This allows the motor's rotor position to be accurately estimated when the PMSM is running at a low speed, making it easier to start and control the speed of the position sensorless motor, thereby improving the accuracy of the PMSM's position sensorless control strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a flow chart of a motor position sensorless control method provided by an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of the structure of a three-phase PMSM provided in an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of the structure of a three-phase winding provided in an embodiment of the present invention;

[0023] Figure 4 A schematic diagram of the structure of a six-phase winding provided in an embodiment of the present invention;

[0024] Figure 5 A schematic diagram of the relationship between various coordinates provided in an embodiment of the present invention;

[0025] Figure 6 Another schematic diagram of the relationship between various coordinates provided in an embodiment of the present invention;

[0026] Figure 7 A PMSM direct-axis magnetic circuit characteristic curve diagram provided by an embodiment of the present invention;

[0027] Figure 8 A relationship diagram of an actual synchronous rotating coordinate system and an estimated rotor synchronous rotating coordinate system provided by an embodiment of the present invention;

[0028] Fig. 9 A schematic diagram of the structure of a two-stage generalized second-order integrator provided by an embodiment of the present invention;

[0029] Fig.10 A schematic diagram of a comparative example provided for an embodiment of the present invention;

[0030] Fig.11 A structural block diagram of a generalized second-order integrator provided by an embodiment of the present invention;

[0031] Fig.12 A waveform diagram of a given low-frequency signal provided by an embodiment of the present invention;

[0032] Fig.13 A schematic diagram of a waveform of a SOGI filtering signal provided by an embodiment of the present invention;

[0033] Fig.14 A schematic diagram of a waveform of an LPF filtering signal provided by an embodiment of the present invention;

[0034] Fig.15 A schematic structural diagram of a motor position sensorless control system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0036] The embodiment of the present invention provides a motor position sensorless control method. Figure 1 A flow chart of a motor position sensorless control method provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the method of this embodiment includes the following steps:

[0037] Step S110: acquiring the multi-phase current of the motor through a current detection module.

[0038] like Figure 2 As shown, Figure 2 A schematic structural diagram of a three-phase PMSM provided in an embodiment of the present invention. Figure 2 The rotor of the motor shown is a built-in rotor structure. The rotor is arranged inside the stator, the stator is provided with a stator coil, and the rotor is provided with a permanent magnet. The built-in rotor structure can make full use of the magnetic resistance torque generated by the asymmetry of the rotor magnetic circuit to improve the power density of the motor. The built-in rotor structure has a magnetic material with a large magnetic permeability between adjacent permanent magnetic poles, and belongs to a salient pole rotor structure in terms of electromagnetic performance.

[0039] Optionally, the motor may include three-phase current or six-phase current. The stator of a three-phase PMSM consists of three-phase symmetrical windings. The stator of a six-phase PMSM consists of two sets of three-phase symmetrical windings, but the neutral point between the two sets of windings is isolated. Figure 3 A schematic diagram of the structure of a three-phase winding provided in an embodiment of the present invention, Figure 4 A schematic diagram of the structure of a six-phase winding provided in an embodiment of the present invention.

[0040] Step S120: transform the multiphase current into synchronous rotating coordinates and inject a high-frequency injection signal into the estimated synchronous rotating coordinate system. axis.

[0041] like Figure 5 As shown, Figure 5A schematic diagram of the coordinate relationship provided by an embodiment of the present invention. ABC is a natural coordinate system, α-β is a stationary coordinate system, and dq is a synchronous rotating coordinate system. In order to simplify the mathematical model of the three-phase PMSM in the natural coordinate system, the coordinate transformation used usually includes a stationary coordinate transformation (Clark transformation) and a synchronous rotating coordinate transformation (Park transformation). The coordinate relationship between them is as follows: Figure 5 As shown, the angle between the A axis of the natural coordinate system and the d axis of the synchronous rotating coordinate system is θ e For multi-phase windings, each set of three-phase symmetrical windings can be regarded as a basic unit, and the traditional phase motor coordinate transformation is used for each basic unit. Define various coordinate system relationships such as Figure 6 As shown, Figure 6 Another schematic diagram of the coordinate relationship provided by the embodiment of the present invention, wherein ABC is the first set of windings, UVW is the second set of windings, α1-β1 and α2-β2 are stationary coordinate systems, and d1-q1 and d2-q2 are synchronous rotating coordinate systems.

[0042] When the motor runs at zero speed and very low speed, the signal-to-noise ratio of the useful signal is very low and is usually difficult to extract, which ultimately leads to failure in detecting the rotor position and speed when the motor runs at zero speed and low speed. In order to obtain accurate rotor position information at all speeds including zero speed, high-frequency injection signal is an effective way to solve this problem. The basic idea is to superimpose a high-frequency voltage (or current) signal on the fundamental signal and apply it to the three-phase winding of the motor. The corresponding high-frequency current (or voltage) will carry the rotor position information. Through a bandpass filter, this current (or voltage) signal is extracted and properly processed to estimate the rotor position. Optionally, the high-frequency injection signal is a high-frequency pulse voltage. Exemplarily, the high-frequency pulse voltage can be a high-frequency sinusoidal voltage.

[0043] Figure 7 This is a PMSM direct-axis magnetic circuit characteristic curve diagram provided by an embodiment of the present invention, wherein the horizontal axis i is the current value and the vertical axis is the magnetic flux. f is the equivalent excitation current of the permanent magnet, and point A is the working point of the d-axis magnetic circuit. When the high-frequency injection signal of the d-axis is greater than 0, the magnetic flux and the d-axis current have the same direction, and the magnetic flux will move toward point C in the figure, and the magnetic circuit will eventually saturate. At this time, the d-axis inductance value will decrease and be significantly smaller than the q-axis inductance value, and the motor will show a magnetic saturation salient pole effect to the outside. Therefore, the motor rotor position can be estimated by directly injecting a high-frequency voltage signal into the d-axis.

[0044] Optionally, the multi-phase currents are subjected to synchronous rotating coordinate transformation, including:

[0045] The flux equation of multi-phase current in the actual synchronous rotating coordinate system is shown in the formula:

[0046]

[0047] The voltage equation of multi-phase current in the actual synchronous rotating coordinate system is shown in the formula:

[0048]

[0049] Among them, u d is the d-axis component of the stator voltage in the actual synchronous rotating coordinate system; u q is the q-axis component of the stator voltage in the actual synchronous rotating coordinate system; I d is the d-axis component of the stator current in the actual synchronous rotating coordinate system; i q is the q-axis component of the stator current in the actual synchronous rotating coordinate system; R s is the stator resistance; q is the q-axis component of the stator flux in the actual synchronous rotating coordinate system; d is the d-axis component of the stator flux in the actual synchronous rotating coordinate system; ω e is the electrical angular velocity of the motor; L d is the d-axis component of the stator inductance in the actual synchronous rotating coordinate system; L q is the d-axis component of the stator inductance in the actual synchronous rotating coordinate system; t is the time.

[0050] Substituting the formula into the equation, we get the voltage equation of PMSM in the d, q coordinate system:

[0051]

[0052] The stator impedance of a PMSM motor is:

[0053]

[0054] Under ideal conditions, the stator resistance of the PMSM motor is negligible compared to the motor impedance, that is, R s = Z. When the motor is at low speed, the cross-coupling term and the back EMF part can be ignored, and the motor electrical angular velocity ω e Compared to the injected high frequency voltage frequency ω h Too small, that is, ω e =ω h ,ω e Can be ignored. Then the PMSM voltage model can be simplified to the following formula:

[0055]

[0056] Similar to traditional three-phase motors, multi-phase motors can also express the relationship between the voltage, current and flux of each phase winding based on the basic electromagnetic principle of the motor. The mathematical model can then be simplified by selecting an appropriate coordinate transformation matrix, which will not be described here.

[0057] Figure 8 8 shows the relationship between the actual synchronous rotating coordinate system dq and the estimated synchronous rotating coordinate system of the PMSM. , where θ is the actual rotor position angle in the actual synchronous rotating coordinate system, is the estimated rotor position angle in the estimated synchronous rotating coordinate system. It should be noted that in the estimated rotor synchronous rotating coordinate system In the estimated rotor synchronous rotating coordinate system, the PMSM flux equation and voltage equation are the same as those in the actual synchronous rotating coordinate system, and will not be repeated here. After injecting the high frequency injection signal into the rotor, the present embodiment estimates the rotor synchronous rotating coordinate system Can be obtained separately The first current signal of the axis In order to facilitate the first current signal Extract rotor position information.

[0058] Step S130: estimate the synchronous rotation coordinate system The first current signal of the axis Through the first generalized second-order integrator, filtering is performed to obtain High frequency current signal of the shaft

[0059] Fig. 9 A schematic diagram of a two-stage generalized second-order integrator provided in an embodiment of the present invention. Optionally, the first current signal Through the first generalized second-order integrator, filtering is performed to obtain High frequency current signal of the shaft The first current signal Input to the input terminal of the first generalized second-order integrator, and output terminal of the first generalized second-order integrator output High frequency current signal of the shaft The first generalized second-order integrator acts as a bandpass filter to filter the first current signal Extracted from High frequency current signal of the shaft

[0060] in,

[0061] k1 is the adjustment parameter of the first generalized second-order integrator; s is the complex frequency variable.

[0062] The first generalized second-order integrator is equivalent to a bandpass filter, which is Extract high frequency current signal from And output.

[0063] In a specific example, the six-phase current of the PMSM is detected by the current detection module, and the high-frequency component is obtained through Clark transformation and Park transformation. Shaft current, high frequency current is extracted using a generalized second-order integrator Its transfer function is as shown in the above formula, and the input of the previous SOGI system is The output is the high frequency current you want to extract ω h is the frequency of the high-frequency signal, k 1 These are the adjustment parameters of the front-end SOGI system.

[0064] Step S140: convert the high frequency current signal and (-sinω h t) multiplied by Axis current modulation signal ω h The frequency of the high-frequency injection signal.

[0065] Step S150: modulate the current signal The low-frequency current component containing the rotor position information is obtained by filtering through the second generalized second-order integrator.

[0066] The high frequency current signal After the influence of the high-frequency injection signal, a current modulation signal is formed. The current modulation signal Contains high-frequency components and low-frequency components, and the second generalized second-order integrator is equivalent to a low-pass filter, thereby extracting the low-frequency current component, which contains the rotor position information.

[0067] In the embodiment of the present invention, the rotor position of the motor when running at low speed is obtained by combining a two-stage generalized second-order integrator with a high-frequency injection signal. Specifically, in the position sensorless control process of the PMSM, the multi-phase current of the motor is obtained by the current detection module and transformed into a synchronous rotating coordinate system. After injecting a high-frequency injection signal into the estimated synchronous rotating coordinate system, The first current signal of the axis Transmitted to the first generalized second-order integrator to extract the high-frequency current signal The high-frequency current signal at the output of the first generalized second-order integrator and (-sinω h t) multiply to form Axis current modulation signal Then the current modulation signal The input is sent to the second generalized second-order integrator for low-pass filtering to obtain the low-frequency current component of the rotor position information. This allows the motor's rotor position to be accurately estimated when the PMSM is running at a low speed, making it easier to start and control the speed of the position sensorless motor, thereby improving the accuracy of the PMSM's position sensorless control strategy.

[0068] The above is the core idea of ​​the present invention. The technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0069] Continue to refer Figure 7 ,according to Figure 7 The dq coordinate system and The relationship between the coordinate systems can be calculated separately with u dh 、u qh relationship and with i dh 、i qh The relationship is shown in the formula, where High frequency sine wave voltage excitation Voltage, is the response to high frequency sinusoidal voltage excitation Current, Δθ is the rotor position angle error.

[0070] Optionally, obtaining a first differential equation includes:

[0071] After injecting the high-frequency injection signal, the d-axis voltage component u of the actual synchronous rotating coordinate system is obtained dh , the q-axis voltage component u of the actual synchronous rotating coordinate system qh , estimate the synchronously rotating coordinate system Shaft voltage component Estimate the synchronous rotation coordinate system Shaft voltage component The first relation formula is:

[0072]

[0073] Among them, i dh is the d-axis current component of the actual synchronous rotating coordinate system under the excitation of the high-frequency injection signal; i qhis the q-axis current component of the actual synchronous rotating coordinate system under the excitation of the high-frequency injection signal;

[0074] According to the first relationship formula, Shaft voltage component, Shaft voltage component, The shaft current component and The second relation formula for the shaft current components is:

[0075]

[0076] Where, L 1 is the common mode inductance, L 2 is the differential mode inductance;

[0077]

[0078] Inverting the second relationship gives the first differential equation:

[0079]

[0080] Optionally, the first current signal Through the first generalized second-order integrator, filtering is performed to obtain High frequency current signal of the shaft include:

[0081] After injecting the high-frequency injection signal, the synchronous rotating coordinate system is estimated Shaft voltage component and estimate the synchronous rotation coordinate system Shaft voltage component for:

[0082]

[0083] Among them, U h is the amplitude of the injected high frequency injection signal; ω h is the frequency of the injected high frequency sinusoidal wave voltage.

[0084] Get the first differential equation:

[0085]

[0086] Among them, L 1 is the common mode inductance, L 2 is the differential mode inductance;

[0087]

[0088] To estimate the synchronous rotating coordinate system under the excitation of high frequency injection signal Shaft current component; To estimate the synchronous rotating coordinate system under the excitation of high frequency injection signal Shaft current component; Δθ is the rotor position angle error; θ is the actual rotor position angle in the actual synchronous rotating coordinate system, is the estimated rotor position angle in the synchronously rotating coordinate system.

[0089] Will Shaft voltage component and Shaft voltage component Substituting into the first differential equation we get the second differential equation;

[0090]

[0091] Integrating the second differential equation yields High frequency current signal of the shaft and High frequency current signal of the shaft High frequency current signal Contains rotor position angle error information.

[0092]

[0093] Therefore, by injecting a high-frequency sinusoidal voltage into the estimated rotating coordinate system, the current of the dq axis response is detected, which contains the rotor position error Δθ, and the rotor position angle can be obtained through the rotor position extraction link. Then, by injecting a high-frequency pulse voltage into the estimated rotating coordinate system of the PMSM, the dq axis current containing the rotor position error can be detected. At this time, we should extract the rotor position angle from it, and we can use the traditional low-pass filter-based method. The input of the first generalized second-order integrator (pre-SOGI system) is The output is the high frequency current you want to extract ω h is the frequency of the high-frequency signal, k 1 These are the adjustment parameters of the front-end SOGI system.

[0094] By the above From the formula, we can see that Both contain rotor position angle error Δθ, but The shaft current formula contains only one factor, so by Shaft current signal, high frequency current signal It is easier to modulate the amplitude of the high-frequency current signal. and (-sinω h t) multiplied by Axis current modulation signal ω hThe frequency of the high-frequency injection signal, including:

[0095] Axis current modulation signal for:

[0096]

[0097] Among them, the current modulation signal The current modulation signal is composed of two factors. The first factor of is the low-frequency current component; the current modulation signal The latter factor of is the high-frequency current component. Therefore, the high-frequency component can be filtered out by a low-pass filter LPF. The SOGI system is used to replace the filter LPF to filter out the high-frequency component and extract the low-frequency current component including the rotor position angle error. That is, the position deviation function is obtained

[0098] Optionally, the current modulation signal The low-frequency current component containing the rotor position information is obtained by filtering through the second generalized second-order integrator, including:

[0099] The current modulation signal input to the input terminal of the second generalized second-order integrator;

[0100] The second generalized second-order integrator acts as a low-pass filter to filter out the current modulation signal The high-frequency current component of the rotor is output, and the low-frequency current component including the rotor position angle error is output, and the position deviation function is obtained.

[0101] Optionally, the motor position sensorless control method may further include: passing the position deviation function into a PI regulator; and the PI regulator controls Δθ to decrease so that the actual rotor position angle is the same as the estimated rotor position angle.

[0102] Since sin2Δθ is approximately equal to 2Δθ, It can be shortened to:

[0103]

[0104] The rotor position angle error Δθ is contained in . In order to make Δθ approach zero and the estimated rotor position approach the true rotor position, the rotor position can be estimated by a PI regulator. The second generalized second-order integrator input is the current modulation signal Output is low frequency current signal k 2is the adjustment parameter of the subsequent SOGI system (second generalized second-order integrator). After that, the rotor position can be estimated using a PI regulator. This embodiment combines a novel SOGI-based position extraction method with a high-frequency pulse voltage injection method, and is applied to a permanent magnet synchronous motor control system to estimate the rotor position when the motor is running at low speed.

[0105] like Fig.10 As shown, Fig.10 A schematic diagram of the structure of a comparative example provided for an embodiment of the present invention. Fig.10 The rotor position detection method based on the traditional low-pass filter first detects the six-phase current of the PMSM containing high-frequency signals. After Clark transformation and Park transformation, we get Shaft current Using the bandpass filter BPF, we can get Shaft high frequency current signal Next, compare it with (-sinω h t) multiplied by Shaft current modulation signal By filtering out the high-frequency component through LPF, a low-frequency current signal containing position angle error can be obtained. Finally, the PI regulator is used to obtain the estimated rotor position angle However, the traditional low-pass filter has a poor ability to extract high-frequency signals, and the extracted motor rotor position angle error is large, especially in the case of speed step and torque step. Therefore, this embodiment replaces the filter with a generalized second-order integrator (SOGI) to extract the rotor position angle, suppress the influence of the step input signal on the high-frequency signal, improve the dynamic performance of the rotor position detection, and reduce the rotor position detection error.

[0106] In order to facilitate the detailed description of the beneficial effects of the two-stage generalized second-order integrator in this embodiment, this embodiment demonstrates its effect graphically through simulation graphics. Fig.11 A generalized second-order integrator structure block diagram provided by an embodiment of the present invention. Wherein, ω is the signal frequency extracted by the SOGI system, X is the system input signal, Y is the system output signal, and k is an adjustable parameter of the system. According to the SOGI structure block diagram, the relationship between X and Y can be deduced as follows:

[0107]

[0108] If you want to extract the low-frequency signal or high-frequency signal contained in the input signal X, you only need to set ω in the figure to the signal frequency you want to extract, and select the best k value through multiple experiments.

[0109] In order to verify that SOGI filtering has better effect, the two filtering methods are first compared and simulated. The given low-frequency signal is superimposed with the high-frequency signal, and filtered by SOGI and LPF respectively. The given low-frequency signal frequency is 100hz, the amplitude is 1V, and the superimposed high-frequency signal frequency is 1khz, and the amplitude is consistent with the given low-frequency signal. ω takes the extracted low-frequency signal frequency as 100×2pi.

[0110] Fig.12 A waveform diagram of a given low-frequency signal provided by an embodiment of the present invention, Fig.13 A waveform diagram of a SOGI filtering signal provided in an embodiment of the present invention, Fig.14 A schematic diagram of the waveform of the LPF filtering signal provided by an embodiment of the present invention. Figure 12 to Figure 14 , the waveform sinusoidality of the LPF filtered signal is poor, and the amplitude after filtering is 0.7V, which is too different from the given low-frequency signal amplitude of 1V. The signal after SOGI filtering has a better sinusoidality and an amplitude of 1V, and the filtering effect is obviously better than LPF. For the high-frequency pulse voltage injection method to detect the rotor position of PMSM at low speed, the generalized second-order integrator is used instead of the traditional filter to reduce the rotor position estimation error.

[0111] and Fig.11 Compared with the comparison example shown, there are two differences: one is the extraction High frequency components in shaft current The comparative example uses BPF, and this embodiment uses the first generalized second-order integrator; one is to extract the low-frequency current signal containing the position angle error The comparative example uses LPF, and the present embodiment uses the second generalized second-order integrator. Therefore, the first generalized second-order integrator is used to extract The shaft high frequency current, the second generalized second order integrator is used to extract the DC component containing the rotor position in the deviation function.

[0112] An embodiment of the present invention also provides a motor position sensorless control system. Fig.15 A schematic diagram of a motor position sensorless control system provided by an embodiment of the present invention is shown in FIG. Fig.15 As shown, the motor position sensorless control system provided by the embodiment of the present invention can execute the motor position sensorless control method provided by any embodiment of the present invention, including:

[0113] A current detection module 11 is used to obtain multi-phase current of the motor;

[0114] A coordinate conversion module 12, used for performing synchronous rotation coordinate conversion on the multi-phase current;

[0115] The high frequency injection module 13 is used to inject a high frequency injection signal into the estimated synchronous rotating coordinate system. axis;

[0116] The first generalized second order integrator 14 is used to estimate the synchronous rotating coordinate system The first current signal of the axis Get High frequency current signal of the shaft

[0117] The modulation module 15 is electrically connected to the output terminal of the first generalized second-order integrator and is used to convert the high-frequency current signal and (-sinω h t) multiplied by Axis current modulation signal ω h is the frequency of the high frequency injection signal;

[0118] The second generalized second-order integrator 16 is used to modulate the current signal Filtering is performed to obtain the low-frequency current component containing the rotor position information.

[0119] In this embodiment, the rotor position of the motor when running at low speed is obtained by combining a two-stage generalized second-order integrator with a high-frequency injection signal. Specifically, in the process of PMSM without position sensor control, the multi-phase current of the motor is obtained by the current detection module and transformed into a synchronous rotating coordinate system. After injecting a high-frequency injection signal into the estimated synchronous rotating coordinate system, The first current signal of the axis Transmitted to the first generalized second-order integrator to extract the high-frequency current signal The high-frequency current signal at the output of the first generalized second-order integrator and (-sinω h t) multiply to form Axis current modulation signal Then the current modulation signal The input is sent to the second generalized second-order integrator for low-pass filtering to obtain the low-frequency current component of the rotor position information. This allows the motor's rotor position to be accurately estimated when the PMSM is running at a low speed, making it easier to start and control the speed of the position sensorless motor, thereby improving the accuracy of the PMSM's position sensorless control strategy.

[0120] The motor position sensorless control system provided by the embodiment of the present invention includes the technical features of the motor position sensorless control method provided by any embodiment of the present invention, and has the beneficial effects of the corresponding technical features, which will not be repeated here.

[0121] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A motor position sensorless control method, characterized in that: include: Acquire the multi-phase current of the motor through the current detection module; The multiphase current is subjected to synchronous rotating coordinate transformation, and a high-frequency injection signal is injected into the estimated synchronous rotating coordinate system. axis; The estimated synchronous rotation coordinate system The first current signal of the axis The filtering process is performed by the first generalized second-order integrator to obtain the High frequency current signal of the shaft The high frequency current signal and (-sinω h t) are multiplied to obtain the Axis current modulation signal The ω h is the frequency of the high-frequency injection signal; The current modulation signal The low-frequency current component containing the rotor position information is obtained by filtering through the second generalized second-order integrator.

2. The motor position sensorless control method according to claim 1, characterized in that: The motor includes three-phase current or six-phase current; The high-frequency injection signal is a high-frequency pulse voltage.

3. The motor position sensorless control method according to claim 1, characterized in that: The multi-phase current is subjected to synchronous rotation coordinate transformation, comprising: The flux equation of the multi-phase current in the actual synchronous rotating coordinate system is as shown in the formula: The voltage equation of the multiphase current in the actual synchronous rotating coordinate system is shown in the formula: Among them, u d is the d-axis component of the stator voltage in the actual synchronous rotating coordinate system; u q is the q-axis component of the stator voltage in the actual synchronous rotating coordinate system; i d is the d-axis component of the stator current in the actual synchronous rotating coordinate system; i q is the q-axis component of the stator current in the actual synchronous rotating coordinate system; R s is the stator resistance; q is the q-axis component of the stator flux in the actual synchronous rotating coordinate system; d is the d-axis component of the stator flux in the actual synchronous rotating coordinate system; ω e is the electrical angular velocity of the motor; L d is the d-axis component of the stator inductance in the actual synchronous rotating coordinate system; L q is the d-axis component of the stator inductance in the actual synchronous rotating coordinate system; t is the time.

4. The motor position sensorless control method according to claim 1, characterized in that: The first current signal The filtering process is performed by the first generalized second-order integrator to obtain the High frequency current signal of the shaft include: The first current signal The first generalized second-order integrator outputs the High frequency current signal of the shaft The first generalized second-order integrator acts as a bandpass filter to filter the first current signal Extract the High frequency current signal of the shaft k1 is the adjustment parameter of the first generalized second-order integrator; s is the complex frequency variable.

5. The motor position sensorless control method according to claim 1, characterized in that: The first current signal The filtering process is performed by the first generalized second-order integrator to obtain the High frequency current signal of the shaft include: After injecting the high frequency injection signal, the estimated synchronous rotating coordinate system Shaft voltage component and the estimated synchronously rotating coordinate system Shaft voltage component for: Among them, U h is the amplitude of the injected high frequency injection signal; Get the first differential equation: Among them, L1 is the common mode inductor, and L2 is the differential mode inductor; is the estimated synchronous rotating coordinate system under the excitation of the high frequency injection signal Shaft current component; is the estimated synchronous rotating coordinate system under the excitation of the high frequency injection signal Shaft current component; Δθ is the rotor position angle error; θ is the actual rotor position angle in the actual synchronous rotating coordinate system, is the estimated rotor position angle in the synchronously rotating coordinate system. The Shaft voltage component and Shaft voltage component Substituting into the first differential equation we get the second differential equation; Integrating the second differential equation yields High frequency current signal of the shaft and stated High frequency current signal of the shaft 6. The motor position sensorless control method according to claim 5, characterized in that: Obtain the first differential equation, including: After injecting the high-frequency injection signal, the d-axis voltage component u of the actual synchronous rotating coordinate system is obtained. dh , the q-axis voltage component u of the actual synchronous rotating coordinate system qh , the estimated synchronously rotating coordinate system Shaft voltage component The estimated synchronously rotating coordinate system Shaft voltage component The first relation formula is: Among them, i dh is the d-axis current component of the actual synchronous rotating coordinate system under the excitation of the high-frequency injection signal; i qh is the q-axis current component of the actual synchronous rotating coordinate system under the excitation of the high-frequency injection signal; According to the first relationship formula, Shaft voltage component, Shaft voltage component, The shaft current component and The second relation formula for the shaft current components is: Inverting the second relationship formula yields the first differential equation:

7. The motor position sensorless control method according to claim 5, characterized in that: The high frequency current signal and (-sinω h t) are multiplied to obtain the Axis current modulation signal The ω h is the frequency of the high-frequency injection signal, including: Said Axis current modulation signal for: Wherein, the current modulation signal The first factor of is the low-frequency current component; the current modulation signal The latter factor of is the high-frequency current component.

8. The motor position sensorless control method according to claim 7, characterized in that: The current modulation signal The low-frequency current component containing the rotor position information is obtained by filtering through the second generalized second-order integrator, including: The current modulation signal input to the input terminal of the second generalized second-order integrator; The second generalized second-order integrator acts as a low-pass filter to filter out the current modulation signal The high-frequency current component of the rotor is output, and the low-frequency current component including the rotor position angle error is output, and the position deviation function is obtained.

9. The motor position sensorless control method according to claim 8, characterized in that: Also includes: Passing the position deviation function into a PI regulator; The PI regulator controls Δθ to decrease so that the actual rotor position angle is the same as the estimated rotor position angle.

10. A motor position sensorless control system, characterized in that: The method for controlling a motor without a position sensor according to any one of claims 1 to 9 comprises: A current detection module is used to obtain the multi-phase current of the motor; A coordinate conversion module, used for performing synchronous rotation coordinate conversion on the multi-phase current; The high frequency injection module is used to inject the high frequency injection signal into the estimated synchronous rotating coordinate system. axis; The first generalized second-order integrator is used to estimate the synchronously rotating coordinate system The first current signal of the axis Get the High frequency current signal of the shaft A modulation module is electrically connected to the output end of the first generalized second-order integrator, and is used to convert the high-frequency current signal and (-sinω h t) are multiplied to obtain the Axis current modulation signal The ω h is the frequency of the high-frequency injection signal; The second generalized second-order integrator is used to modulate the current signal Filtering is performed to obtain the low-frequency current component containing the rotor position information.

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