Motor non-inductive observation system and method and unmanned aerial vehicle

Abstract

The invention is suitable for the field of motor control, and provides a motor non-inductive observation system and method and an unmanned aerial vehicle. The motor non-inductive observation system comprises a controller, and a current acquisition module, a voltage acquisition module, a low-pass filter and a high-pass filter which are electrically connected with the controller, and the cut-off frequencies of the low-pass filter and the high-pass filter are equal. The motor non-inductive observation system can operate in a wide speed range, realizes high precision and robustness, can rapidly converge in an extremely short time, supports closed-loop control close to zero speed, is wide in applicability and simplified in design, does not need to adjust a PI controller or a sliding mode controller in an observer, only needs to set the cut-off frequency of a filter, and avoids a parameter adjustment process.

Description

Technical Field

[0001] The present invention belongs to the field of motor control, and particularly relates to a sensorless motor observation system, method and unmanned aerial vehicle. Background Art

[0002] In the field of motor control, algorithms for calculating angles and speeds without sensors can significantly improve the motor control accuracy, efficiency, and dynamic response performance in sensorless applications. Currently, common algorithms for calculating angles and speeds mainly include: sliding mode observers, non-linear flux link observers, etc. Although these methods have achieved certain results in position calculation, there are still many deficiencies in practical applications. The advantages and disadvantages of these algorithms will be discussed separately below.

[0003] I. Sliding mode observer

[0004] Principle: A sliding mode observer is an observer based on sliding mode control theory. By calculating the error between the current and the true current, it realizes the observation of the extended back electromotive force, making the system state slide on the sliding surface, thereby realizing state estimation.

[0005] Advantages: Strong robustness: It has strong robustness to parameter changes and external disturbances; Simple implementation: The algorithm structure is simple and easy to implement.

[0006] Disadvantages: Chattering problem: The back-and-forth jitter on the sliding mode gain may cause output chattering and affect the observation accuracy; Low-speed performance: The back electromotive force has a small amplitude at low motor speeds, and the observation performance is poor.

[0007] II. Non-linear flux link observer

[0008] Principle: The non-linear flux link observer is based on the non-linear model of the motor. By designing the non-linear observer equation, it realizes the estimation of the flux link.

[0009] Advantages: Good low-speed performance: The observation method based on the flux link is not affected at low speeds; Strong adaptability: It is applicable to various motor types and operating conditions.

[0010] Disadvantages: Poor robustness: The flux link observation without considering the saliency of the motor is sensitive to parameter changes; Complex calculation: The design and implementation of the non-linear observer are more complex, with a large amount of calculation and high requirements for hardware resources. Summary of the Invention

[0011] The purpose of the present invention is to provide a sensorless motor observation system, method and unmanned aerial vehicle, aiming to solve the problems of low observation accuracy and poor low-speed performance existing in the sliding mode observer, and the problems of poor robustness and complex calculation existing in the non-linear flux link observer.

[0012] In a first aspect, the present invention provides a motor sensorless observation system, comprising a controller and a current acquisition module, a voltage acquisition module, a low-pass filter and a high-pass filter electrically connected to the controller respectively, wherein the cutoff frequencies of the low-pass filter and the high-pass filter are equal;

[0013] The current acquisition module is used to measure the motor stator current in real time;

[0014] The voltage acquisition module is used to measure the motor stator voltage;

[0015] The low-pass filter is used to filter the effective flux linkage of the motor stator of the current model;

[0016] The high-pass filter is used to filter the effective flux linkage of the motor stator of the voltage model;

[0017] The controller is used to implement a voltage model algorithm according to the stator resistance, the motor stator current measured by the current acquisition module and the motor stator voltage measured by the voltage acquisition module to obtain the effective magnetic flux of the motor stator of the voltage model; implement a current model algorithm according to the angle of the motor rotor, the motor stator inductance, the motor stator current measured by the current acquisition module and the magnetic flux generated by the permanent magnet to obtain the effective magnetic flux of the motor stator of the current model; output the effective magnetic flux of the motor stator of the voltage model to a high-pass filter for filtering, output the effective magnetic flux of the motor stator of the current model to a low-pass filter for filtering, and add the filtered effective magnetic flux of the motor stator of the voltage model and the effective magnetic flux of the motor stator of the current model to obtain the observed α-β axis motor stator effective magnetic flux, then convert the effective magnetic flux of the motor stator into the effective magnetic flux of the motor rotor, and calculate the current angle of the motor rotor by the inverse tangent method.

[0018] In a second aspect, the present invention provides a motor sensorless observation method, the method comprising the following steps:

[0019] The controller measures the stator resistance and current

[0020] The motor stator voltage measured by the motor stator current and voltage acquisition module implements the voltage model algorithm to obtain the effective magnetic flux of the motor stator of the voltage model; the current model algorithm is implemented according to the angle of the motor rotor, the motor stator inductance, the motor stator current measured by the current acquisition module and the magnetic flux generated by the permanent magnet to obtain the effective magnetic flux of the motor stator of the current model; the cut-off frequency is the cut-off frequency of the low-pass filter and the high-pass filter, and the cut-off frequency of the low-pass filter and the high-pass filter are equal;

[0021] The effective stator flux linkage of the motor in the controller output voltage model is filtered by a high-pass filter, and the effective stator flux linkage of the motor in the output current model is filtered by a low-pass filter. The filtered effective stator flux linkage of the voltage model of the motor and the effective stator flux linkage of the current model of the motor are added to obtain the observed effective stator flux linkage of the α-β axis of the motor;

[0022] The controller converts the effective stator flux linkage of the motor into the effective rotor flux linkage of the motor;

[0023] The controller calculates the current angle of the motor rotor through the arctangent method using the effective rotor flux linkage of the motor.

[0024] Thirdly, the present invention provides a drone including the motor sensorless observation system described above.

[0025] The beneficial effects of the motor sensorless observation system of the present invention are as follows:

[0026] 1. Wide speed range operation:

[0027] The motor sensorless observation system of the present invention combines the advantages of the current model and the voltage model, realizes full-range operation from zero speed to high speed, adapts to various flight conditions of the drone (hovering, high-speed flight, rapid maneuvering), and no longer requires PI tuning when using a combination of low-pass and high-pass filters.

[0028] 2. High precision and robustness:

[0029] When the motor frequency is lower than the cut-off frequency, the current model avoids the integration error of the voltage model and the non-linearity problem of the inverter, improving the observation accuracy. When the motor frequency is higher than the cut-off frequency, the voltage model ensures the stability and dynamic performance of the observer.

[0030] 3. Fast convergence:

[0031] The motor sensorless observation system of the present invention can converge quickly in an extremely short time, supports closed-loop control close to zero speed, improves the stability of low-speed hovering and takeoff and landing, and realizes high-precision estimation of the motor rotor position.

[0032] 4. Wide applicability:

[0033] The concept of effective flux linkage makes it applicable to various motor types, including SPMSM and IPMSM. The motor sensorless observation system of the present invention has strong robustness to motor parameter changes and external disturbances.

[0034] 5. Simplified design:

[0035] Combining the advantages of the voltage model and the current model, the concept of effective flux linkage and the structure of a hybrid observer are introduced, simplifying the design and implementation of the flux linkage observer. The introduction of the effective flux linkage concept solves the salient pole problem caused by the different permeabilities of permanent magnets and iron core materials, and is applicable to SPMSM and IPMSM. The design of the hybrid effective flux linkage observer combines the current model (excellent low-speed performance) and the voltage model (good high-speed stability) to achieve high-precision flux linkage observation over the entire speed range.

[0036] 6. Filter Design:

[0037] Low-pass and high-pass filters with equal cut-off frequencies are used to process the flux linkages of the voltage model and the current model respectively, and then the two are added to obtain the final α-β axis flux linkage, improving the observation accuracy and dynamic response. Compared with the traditional hybrid flux linkage scheme, this method no longer requires adjusting the PI controller or sliding mode controller inside the observer, but only needs to set the filter cut-off frequency, avoiding the parameter tuning process.

[0038] 7. Method for Estimating the Motor Rotor Position:

[0039] The motor rotor angle is calculated by the arctangent method to achieve high-precision position estimation, which is applicable to the sensorless control scenario.

[0040] 8. Performance of the Sensorless Observation System of the Motor of the Present Invention:

[0041] At low speeds, the current model dominates, improving the observation accuracy and robustness.

[0042] At high speeds, the voltage model dominates, ensuring the stability of the observer. Brief Description of the Drawings

[0043] Figure 1 It is the functional module block diagram of the sensorless observation system of the motor provided by the embodiment of the present invention.

[0044] Figure 2 It is the comparison diagram of the angle calculated by the sensorless observation system of the motor provided by the embodiment of the present invention and the actual motor angle.

[0045] Figure 3 It is the flow chart of the sensorless observation method of the motor provided by the embodiment of the present invention. Detailed Description of the Invention

[0046] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] To illustrate the technical solution of the present invention, the following will be described through specific embodiments.

[0048] Please refer to Figure 1 , the sensorless observation system for the motor provided by the embodiment of the present invention includes a controller 11, and a current acquisition module 12, a voltage acquisition module 13, a low-pass filter 14, and a high-pass filter 15 that are respectively electrically connected to the controller 11. The cut-off frequencies of the low-pass filter 14 and the high-pass filter 15 are equal;

[0049] The current acquisition module 12 is used to measure the stator current of the motor in real time;

[0050] The voltage acquisition module 13 is used to measure the stator voltage of the motor;

[0051] The low-pass filter 14 is used to filter the effective stator magnetic flux of the current model of the motor;

[0052] The high-pass filter 15 is used to filter the effective stator magnetic flux of the voltage model of the motor;

[0053] The controller 11 is used to implement the voltage model algorithm according to the stator resistance, the stator current of the motor measured by the current acquisition module, and the stator voltage of the motor measured by the voltage acquisition module to obtain the effective stator magnetic flux of the voltage model of the motor; according to the angle of the motor rotor, the stator inductance of the motor, the stator current of the motor measured by the current acquisition module, and the magnetic flux generated by the permanent magnet, implement the current model algorithm to obtain the effective stator magnetic flux of the current model of the motor; output the effective stator magnetic flux of the voltage model of the motor to the high-pass filter for filtering, output the effective stator magnetic flux of the current model of the motor to the low-pass filter for filtering, and add the filtered effective stator magnetic flux of the voltage model of the motor and the effective stator magnetic flux of the current model of the motor to obtain the observed effective stator magnetic flux of the α-β axis of the motor, and then convert the effective stator magnetic flux of the motor into the effective magnetic flux of the motor rotor, and calculate the current angle of the motor rotor through the arctangent method.

[0054] In the embodiment of the present invention, the angle of the motor rotor is calculated by the sensorless observation system for the motor provided by the embodiment of the present invention. Since the sensorless observation system for the motor provided by the embodiment of the present invention can quickly converge to the true value, the initial value of the angle of the motor rotor does not need to be deliberately set to a certain value.

[0055] The magnetic flux generated by the permanent magnet is calculated in the following way: Connect the oscilloscope channel to any two phases of the motor, and calculate the magnetic flux generated by the permanent magnet through the no-load back electromotive force test.

[0056] The motor stator inductance is obtained in the following way: Use a short - circuit calibration fixture (short - circuit the test terminals) to perform a zero - clearing operation to eliminate the influence of parasitic parameters. Start the automatic measurement function, connect the LCR meter to the motor stator inductance to be measured, and the LCR meter will display the inductance value. The LCR meter is an electronic test instrument used to measure inductance (L), capacitance (C), and resistance (R).

[0057] The stator resistance is obtained in the following way: Apply a short - circuit current with a DC power supply, and the ratio of the obtained voltage to the current is the resistance value, thus measuring the stator resistance value.

[0058] In the embodiment of the present invention, the voltage model formula is: , where represents the effective stator magnetic flux of the motor on the α - axis in the two - phase stationary α - β coordinate system of the motor, represents the effective stator magnetic flux of the motor on the β - axis in the two - phase stationary α - β coordinate system of the motor, represents the voltage component of the motor on the α - axis, represents the voltage component of the motor on the β - axis, represents the current component of the motor on the α - axis, represents the current component of the motor on the β - axis, Rs is the stator resistance. The voltage model depends on the real - time sampling of voltage and current, without requiring speed feedback, but there are integral drift problems (such as initial value error, low - frequency integral saturation).

[0059] The current model formula is: , where represents the effective stator magnetic flux of the motor on the α - axis in the two - phase stationary α - β coordinate system of the motor, represents the effective stator magnetic flux of the motor on the β - axis in the two - phase stationary α - β coordinate system of the motor, θ is the angle of the motor rotor, represents the d - axis inductance, represents the q - axis inductance, represents the d - axis current, represents the q - axis current, ψ f represents the magnetic flux generated by the permanent magnet. The current model is sensitive to motor parameters but has a better dynamic response and is often used in low - speed scenarios.

[0060] The effective stator magnetic flux of the output voltage model of the motor is filtered by a low - pass filter, and the effective stator magnetic flux of the output current model of the motor is filtered by a high - pass filter, and the filtered effective stator magnetic flux of the voltage model of the motor and the filtered effective stator magnetic flux of the current model of the motor are added to obtain the observed effective stator magnetic flux of the α - β axis of the motor. Specifically:

[0061]

[0062] Through the combination of a high-pass filter (HPF) and a low-pass filter (LPF), the fusion process is carried out on the effective stator flux of the motor in the filtered voltage model and the effective stator flux of the motor in the current model; among them, is the observed effective stator flux of the α-β axis motor, s represents the frequency in the Laplace transform domain, and K p and K i are filter parameters that determine the filtering characteristics. represents the effective stator flux of the motor calculated based on the voltage model; represents the effective stator flux of the motor calculated based on the current model;

[0063] To simplify the calculation process, let K i = 0 to obtain a pair of first-order high-pass and low-pass filters with equal cut-off frequencies as shown below. , representing a pair of first-order low-pass and high-pass filters with equal cut-off frequencies, and the cut-off frequency is 1 / Kp.

[0064] That is to say, by simplifying the formula, only one cut-off frequency needs to be adjusted to obtain the effective stator flux of the motor under the hybrid model. Finally, the two effective fluxes are added to obtain the observed α-β axis stator flux.

[0065] The formula for converting the effective stator flux of the motor into the effective rotor flux of the motor is:

[0066] , where represents the effective stator flux of the α-axis of the motor in the two-phase stationary α-β coordinate system of the motor, represents the effective stator flux of the β-axis of the motor in the two-phase stationary α-β coordinate system of the motor, represents the q-axis inductance, represents the current component of the α-axis of the motor in the two-phase stationary α-β coordinate system of the motor, represents the current component of the β-axis of the motor in the two-phase stationary α-β coordinate system of the motor, represents the effective rotor flux of the α-axis of the motor in the two-phase stationary α-β coordinate system of the motor, represents the effective rotor flux of the β-axis of the motor in the two-phase stationary α-β coordinate system of the motor.

[0067] In the actual application of the motor, the air-gap permeance of the motor = the permeance of the permanent magnet < the permeance of the iron core material. This will lead to uneven distribution of the motor magnetic field. The surface-mounted motor will also generate saliency with unequal dq-axis inductances. With saliency, the magnetic flux of the motor not only includes the magnetic flux ψ f of the permanent magnet itself, but also should include the part generated by the d-axis current . Introducing the concept of the effective magnetic flux will result in a more accurate formula description of the motor model and improve the control performance.

[0068] In the embodiment of the present invention, the definition of the effective magnetic flux linkage is as follows:

[0069] , where represents the direct-axis total magnetic flux linkage, ψ f represents the magnetic flux linkage constant, the magnetic flux generated by the permanent magnet, which is provided by the internal permanent magnet of the motor. and respectively represent the direct-axis inductance and the quadrature-axis inductance. represents the correction term of the direct-axis current to the magnetic flux linkage. The above formula represents for the SPMSM (Surface Permanent Magnet Synchronous Motor), since the direct-axis inductance Ld is equal to the quadrature-axis inductance Lq, that is, there is no salient pole effect, so the direct-axis magnetic flux linkage is only determined by the magnetic flux linkage ψ f of the permanent magnet itself, and the direct-axis current id will not have an additional effect on the magnetic flux linkage through the inductance difference. For the IPMSM (Interior Permanent Magnet Synchronous Motor), since the direct-axis inductance is less than the quadrature-axis inductance, that is, there is a salient pole effect, so in addition to the magnetic flux linkage ψ f of the permanent magnet itself, the modulation effect of the difference between the direct-axis inductance Ld and the quadrature-axis inductance Lq on the direct-axis current id also needs to be considered.

[0070] Adopting the sensorless observation system for the motor provided by the embodiment of the present invention, the final result is as Figure 2 shown. The observation system can quickly converge in a very short time to achieve near zero-speed closed-loop. Among them, the initial value that is relatively high is the motor angle calculated by the observation system, and the initial value that is near 1 is the actual motor angle. The speed target value is given to the system at the beginning of the first second, and after 10 ms, the angle of the observation system quickly converges to the actual motor angle to achieve the effect of fast zero-speed closed-loop.

[0071] In the embodiment of the present invention, the current acquisition module 12 can adopt a current sensor, such as a Hall effect current sensor. The voltage acquisition module 13 can adopt a voltage sensor, such as a resistor voltage divider or a dedicated voltage sensor; the controller 11 can adopt a digital signal processor (DSP) or a microcontroller (MCU). For example, the TMS320F28335 DSP of TI has high-speed floating-point operation ability and is suitable for processing complex magnetic flux calculation algorithms.

[0072] Please refer to Figure 3 , the sensorless observation method for the motor provided by the embodiment of the present invention includes the following steps:

[0073] The controller implements a voltage model algorithm based on the stator resistance, the motor stator current measured by the current acquisition module, and the motor stator voltage measured by the voltage acquisition module to obtain the effective stator magnetic flux of the voltage model; implements a current model algorithm based on the angle of the motor rotor, the motor stator inductance, the motor stator current measured by the current acquisition module, and the magnetic flux generated by the permanent magnet to obtain the effective stator magnetic flux of the current model; the cut-off frequency is the cut-off frequency of the low-pass filter and the high-pass filter, and the cut-off frequencies of the low-pass filter and the high-pass filter are equal;

[0074] The controller outputs the effective stator magnetic flux of the voltage model to the high-pass filter for filtering, outputs the effective stator magnetic flux of the current model to the low-pass filter for filtering, and adds the filtered effective stator magnetic flux of the voltage model and the effective stator magnetic flux of the current model to obtain the observed effective stator magnetic flux of the α-β axis;

[0075] The controller converts the effective stator magnetic flux into the effective rotor magnetic flux;

[0076] The controller calculates the current angle of the motor rotor from the effective rotor magnetic flux by the arctangent method.

[0077] The motor fluxless observation method provided by the embodiment of the present invention and the motor fluxless observation system provided by the embodiment of the present invention belong to the same concept. The specific implementation process is detailed in the full text of the specification and will not be repeated here.

[0078] The embodiment of the present invention also provides a drone including the motor fluxless observation system provided by the embodiment of the present invention.

[0079] The motor fluxless observation system of the present invention can operate in a wide speed range, achieve high precision and robustness, can converge quickly in an extremely short time, support closed-loop control close to zero speed, has wide applicability, simplifies the design, no longer requires adjusting the PI controller or the sliding mode controller in the observer, only needs to set the filter cut-off frequency, and avoids the parameter adjustment process.

[0080] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A motor sensorless observation system, characterized in that: It includes a controller and a current acquisition module, a voltage acquisition module, a low-pass filter and a high-pass filter which are electrically connected to the controller respectively, and the cut-off frequencies of the low-pass filter and the high-pass filter are equal; The current acquisition module is used to measure the motor stator current in real time; The voltage acquisition module is used to measure the motor stator voltage; The low-pass filter is used to filter the effective flux linkage of the motor stator of the current model; The high-pass filter is used to filter the effective flux linkage of the motor stator of the voltage model; The controller is used to implement a voltage model algorithm according to the stator resistance, the motor stator current measured by the current acquisition module and the motor stator voltage measured by the voltage acquisition module to obtain the effective magnetic flux of the motor stator of the voltage model; implement a current model algorithm according to the angle of the motor rotor, the motor stator inductance, the motor stator current measured by the current acquisition module and the magnetic flux generated by the permanent magnet to obtain the effective magnetic flux of the motor stator of the current model; output the effective magnetic flux of the motor stator of the voltage model to a high-pass filter for filtering, output the effective magnetic flux of the motor stator of the current model to a low-pass filter for filtering, and add the filtered effective magnetic flux of the motor stator of the voltage model and the effective magnetic flux of the motor stator of the current model to obtain the observed α-β axis motor stator effective magnetic flux, then convert the effective magnetic flux of the motor stator into the effective magnetic flux of the motor rotor, and calculate the current angle of the motor rotor by the inverse tangent method.

2. The motor sensorless observation system according to claim 1, characterized in that: The voltage model formula is: ,in, It represents the effective flux linkage of the motor stator on the α-axis in the two-phase stationary α-β coordinate system of the motor. It represents the effective flux linkage of the motor stator on the β axis in the two-phase stationary α-β coordinate system of the motor. represents the voltage component of the motor on the α axis, represents the voltage component of the motor on the β axis, represents the current component of the motor on the α axis, It represents the current component of the motor in the β axis, and Rs is the stator resistance.

3. The motor sensorless observation system according to claim 1, characterized in that: The current model formula is: ,in, It represents the effective flux linkage of the motor stator on the α-axis in the two-phase stationary α-β coordinate system of the motor. It represents the effective flux linkage of the motor stator on the β axis in the two-phase stationary α-β coordinate system of the motor, θ is the angle of the motor rotor, represents the d-axis inductance, represents the q-axis inductance, represents the d-axis current, represents the q-axis current, ψ f Represents the magnetic flux produced by a permanent magnet.

4. The motor sensorless observation system according to claim 1, characterized in that: The effective flux linkage of the motor stator of the output voltage model is filtered by a low-pass filter, and the effective flux linkage of the motor stator of the output current model is filtered by a high-pass filter, and the effective flux linkage of the motor stator of the filtered voltage model and the effective flux linkage of the motor stator of the current model are added to obtain the observed α-β axis motor stator effective flux linkage, which is specifically: Through the combination of high-pass filter HPF and low-pass filter LPF, the effective flux linkage of the motor stator of the filtered voltage model and the effective flux linkage of the motor stator of the current model are fused; wherein, is the observed α-β axis motor stator effective flux, s represents the frequency in the Laplace transform domain, K p and K i is the filter parameter that determines the filtering characteristics, It represents the effective flux linkage of the motor stator calculated based on the voltage model; It represents the effective flux linkage of the motor stator calculated based on the current model; In order to simplify the calculation process, let K i =0 to obtain a pair of first-order high-pass filters and low-pass filters with equal cutoff frequencies as shown below, , represents a pair of first-order low-pass filter and high-pass filter with equal cutoff frequencies, and the cutoff frequency is 1 / Kp.

5. The motor sensorless observation system according to claim 1, characterized in that: The formula for converting the effective flux of the motor stator into the effective flux of the motor rotor is: ,in, It represents the effective flux linkage of the motor stator on the α-axis in the two-phase stationary α-β coordinate system of the motor. It represents the effective flux linkage of the motor stator on the β axis in the two-phase stationary α-β coordinate system of the motor. represents the q-axis inductance, It represents the current component of the α-axis in the two-phase stationary α-β coordinate system of the motor, It represents the current component of the β axis in the two-phase stationary α-β coordinate system of the motor, It represents the effective magnetic flux of the motor rotor on the α-axis in the two-phase stationary α-β coordinate system of the motor. It represents the effective magnetic flux of the motor rotor about the β-axis in the two-phase stationary α-β coordinate system of the motor.

6. The motor sensorless observation system according to claim 1, characterized in that: The definition of effective magnetic linkage is as follows: ,in, is the total direct axis flux, ψ f Represents the flux linkage constant, the flux linkage generated by the permanent magnet, provided by the permanent magnet inside the motor, and They represent the direct-axis inductance and quadrature-axis inductance respectively. It represents the correction term of the direct axis current to the flux linkage. The above formula indicates that for the surface permanent magnet synchronous motor SPMSM, the direct axis flux linkage is only composed of the flux linkage ψ of the permanent magnet itself. f Determination; For the internal permanent magnet synchronous motor IPMSM, the direct axis flux is divided by the flux of the permanent magnet itself ψ f In addition, the direct-axis inductance L d With the quadrature axis inductance L q The difference between the direct axis current i d modulation effect.

7. A motor sensorless observation method, characterized in that: The method comprises the following steps: The controller implements a voltage model algorithm according to the stator resistance, the motor stator current measured by the current acquisition module, and the motor stator voltage measured by the voltage acquisition module to obtain the effective magnetic flux of the motor stator of the voltage model; implements a current model algorithm according to the angle of the motor rotor, the motor stator inductance, the motor stator current measured by the current acquisition module, and the magnetic flux generated by the permanent magnet to obtain the effective magnetic flux of the motor stator of the current model; the cut-off frequency is the cut-off frequency of the low-pass filter and the high-pass filter, and the cut-off frequency of the low-pass filter and the high-pass filter are equal; The effective flux linkage of the motor stator of the controller output voltage model is filtered by a high-pass filter, and the effective flux linkage of the motor stator of the controller output current model is filtered by a low-pass filter, and the effective flux linkage of the motor stator of the filtered voltage model and the effective flux linkage of the motor stator of the current model are added to obtain the observed α-β axis motor stator effective flux linkage; The controller converts the effective flux of the motor stator into the effective flux of the motor rotor; The controller calculates the current angle of the motor rotor using the inverse tangent method based on the effective magnetic flux of the motor rotor.

8. The motor sensorless observation method according to claim 7, characterized in that: The controller outputs the effective flux of the motor stator of the voltage model to a low-pass filter for filtering, outputs the effective flux of the motor stator of the current model to a high-pass filter for filtering, and adds the effective flux of the motor stator of the filtered voltage model and the effective flux of the motor stator of the current model to obtain the observed α-β axis motor stator effective flux, which is specifically: , through the combination of high-pass filter HPF and low-pass filter LPF, the effective flux of the motor stator of the filtered voltage model and the effective flux of the motor stator of the current model are fused; wherein, is the observed α-β axis motor stator effective flux, s represents the frequency in the Laplace transform domain, K p and K i is the filter parameter that determines the filtering characteristics, It represents the effective flux linkage of the motor stator calculated based on the voltage model; It represents the effective flux linkage of the motor stator calculated based on the current model; To simplify the calculation process, let Ki = 0 to obtain a pair of first-order high-pass filters and low-pass filters with equal cutoff frequencies as shown below: , represents a pair of first-order low-pass filter and high-pass filter with equal cutoff frequencies, and the cutoff frequency is 1 / Kp.

9. The motor sensorless observation method according to claim 7, characterized in that: The formula for converting the effective flux of the motor stator into the effective flux of the motor rotor is: ,in, It represents the effective flux linkage of the motor stator on the α-axis in the two-phase stationary α-β coordinate system of the motor. It represents the effective flux linkage of the motor stator on the β axis in the two-phase stationary α-β coordinate system of the motor. represents the q-axis inductance, It represents the current component of the α-axis in the two-phase stationary α-β coordinate system of the motor, It represents the current component of the β axis in the two-phase stationary α-β coordinate system of the motor, It represents the effective magnetic flux of the motor rotor on the α-axis in the two-phase stationary α-β coordinate system of the motor. It represents the effective magnetic flux of the motor rotor about the β-axis in the two-phase stationary α-β coordinate system of the motor.

10. An unmanned aerial vehicle comprising the motor sensorless observation system according to any one of claims 1 to 6.

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