Permanent magnet synchronous motor sensorless control method and system

Abstract

The invention belongs to the technical field of permanent magnet synchronous motor control, discloses a permanent magnet synchronous motor sensorless control method and a permanent magnet synchronous motor sensorless control system, and aims to solve the problem that the motor speed estimation precision of the system is reduced due to serious buffeting of a traditional sliding mode observer in permanent magnet synchronous motor sensorless control. A fractional order-based high-order sliding mode observer is designed, and by introducing a fractional order theory and a high-order sliding mode control method, buffeting of a sliding mode is effectively suppressed, and the estimation precision of the observer is improved. According to the method, a phase-locked loop is designed based on a fractional order expansion state observer and is used for extracting the rotating speed and position information of the motor, so that the estimation precision of the system on the position and the speed of the rotor is further improved. By means of the method, high-precision estimation of the rotor position and the rotor speed can be achieved in the sensorless control process of the permanent magnet synchronous motor system, and it can be guaranteed that the system has high robustness when load disturbance is not matched with parameters.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet synchronous motor control technology, specifically relating to a sensorless control method and system for permanent magnet synchronous motors. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) offer advantages such as high power density, small size, and high efficiency. With the widespread application of permanent magnet materials like neodymium iron boron (NdFeB) and advancements in power electronics technology, PMSMs are increasingly being used in new energy vehicles, aerospace, and intelligent robotics. Achieving precise and efficient control of PMSMs requires rotor position information, which is typically measured using mechanical position sensors such as encoders, rotary transformers, and Hall effect sensors.

[0003] However, installing mechanical position sensors typically presents several problems: First, position sensors are susceptible to external electromagnetic interference, especially in high-frequency, high-speed, and strong electromagnetic environments, which can affect the stability of the motor drive system. Second, position sensors are vulnerable to adverse external conditions such as manufacturing processes, vibration, high temperatures, and high humidity. Installing position sensors under harsh conditions can lead to reduced accuracy, consequently decreasing system reliability; in some cases, sensor failure can even cause system downtime. Third, using these additional position sensors and equipment for position information processing increases costs. In fact, not only the cost of the position sensors themselves needs to be considered, but also wiring, interfaces, and all related expenses. Furthermore, additional position sensors and cable wiring increase system complexity, especially in space-constrained environments, limiting system flexibility.

[0004] To address the aforementioned issues, sensorless control technology has emerged as a reliable solution. This technology accurately estimates rotor position, eliminating the motor's reliance on mechanical position sensors. This not only reduces system costs but also enhances system robustness, enabling stable operation under complex conditions such as high temperature, high humidity, and vibration. Currently, sensorless control technology has been successfully applied in home appliances, power tools, wind power generation, and electric vehicles, demonstrating significant development potential. In conclusion, researching high-performance sensorless control technology not only has important engineering application value and practical significance but also contributes to improving the intelligence level of motor drive systems.

[0005] Sliding mode observers are widely used in sensorless control of permanent magnet synchronous motors (PMSMs) due to their low system model accuracy requirements, simple implementation, and strong robustness. By introducing a discontinuous sign function, the sliding mode observer causes the system state variables to reach a preset sliding surface, which they then maintain. The equivalent control of the sliding mode observer is used to estimate the motor's back electromotive force (EMF), and then a phase-locked loop (PLL) is used to extract the rotor position and velocity information from the back EMF. However, due to the discontinuity of the sign function, the system is prone to severe chattering. Furthermore, although PLLs are commonly used to extract rotor position and velocity information from the back EMF, traditional PLLs suffer from poor estimation accuracy. Summary of the Invention

[0006] The purpose of this invention is to propose a sensorless control method for permanent magnet synchronous motors. This method can improve the system's estimation accuracy of the motor rotor position and speed while ensuring the system has strong robustness under load disturbances and parameter mismatches.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A sensorless control method for a permanent magnet synchronous motor includes the following steps: Step 1. In A mathematical model of the back electromotive force of a permanent magnet synchronous motor is established in a two-phase stationary coordinate system. Step 2. Design the fractional-order sliding surface; Step 3. Based on the mathematical model of the back EMF of the permanent magnet synchronous motor and the fractional sliding mode surface, design a high-order sliding mode observer based on the fractional order to estimate the back EMF of the motor; Step 4. Establish a dynamic model of the permanent magnet synchronous motor with parameter uncertainties; Step 5. Based on the dynamic model of the permanent magnet synchronous motor with parameter uncertainties, a phase-locked loop is designed based on a fractional-order extended state observer and used to estimate the motor speed and position; Step 6. Using the high-order sliding mode observer from Step 3 and the phase-locked loop from Step 5, perform sensorless control of the permanent magnet synchronous motor system.

[0008] Furthermore, based on the sensorless control method for permanent magnet synchronous motors, this invention also proposes a corresponding sensorless control system for permanent magnet synchronous motors, the technical solution of which is as follows: A sensorless control system for a permanent magnet synchronous motor includes: Model building module, used in A mathematical model of the back electromotive force of a permanent magnet synchronous motor is established in a two-phase stationary coordinate system. The sliding surface design module is used to design fractional-order sliding surfaces; The observer design module is used to design a high-order sliding mode observer based on the fractional-order sliding mode surface, based on the mathematical model of the back EMF of the permanent magnet synchronous motor, so as to realize the estimation of the back EMF of the motor. The dynamic model building module is used to establish a dynamic model of a permanent magnet synchronous motor with parameter uncertainties. The phase-locked loop design module is used to design a phase-locked loop based on a fractional-order extended state observer on the basis of a dynamic model of a permanent magnet synchronous motor with parameter uncertainties, and to use it to estimate the motor speed and position. And a sensorless control module for sensorless control of permanent magnet synchronous motor systems using a high-order sliding mode observer and a phase-locked loop.

[0009] Furthermore, based on the aforementioned sensorless control method for permanent magnet synchronous motors, this invention also proposes a computer device, which includes a memory and one or more processors. The memory stores executable code, and when the processor executes the executable code, it implements the steps of the sensorless control method for permanent magnet synchronous motors described above.

[0010] Furthermore, based on the aforementioned sensorless control method for permanent magnet synchronous motors, this invention also proposes a computer-readable storage medium storing a program thereon; when executed by a processor, this program is used to implement the steps of the aforementioned sensorless control method for permanent magnet synchronous motors.

[0011] The present invention has the following advantages: As described above, this invention discloses a sensorless control method for permanent magnet synchronous motors (PMSMs). This method addresses the problem of severe chattering in traditional sliding mode observers used in sensorless control of PMSMs, which leads to reduced accuracy in motor speed estimation. It designs a higher-order sliding mode observer based on fractional-order theory. By introducing fractional-order theory and a higher-order sliding mode control method, chattering is effectively suppressed, improving the observer's estimation accuracy and thus enhancing the system's rotor speed estimation accuracy. To further improve the system's rotor position and speed estimation accuracy while ensuring strong robustness under load disturbances and parameter mismatches, this invention also designs a phase-locked loop (PLL) based on a fractional-order extended state observer and uses it to extract motor speed and position information, thereby further improving the system's rotor position and speed estimation accuracy. This invention not only achieves high-precision estimation of rotor position and speed during sensorless control of PMSM systems but also ensures strong robustness under load disturbances and parameter mismatches. Attached Figure Description

[0012] Figure 1 This is a flowchart of a sensorless control method for a permanent magnet synchronous motor in an embodiment of the present invention.

[0013] Figure 2 This is a structural block diagram of a high-order sliding mode observer based on fractional order in an embodiment of the present invention.

[0014] Figure 3 This is a block diagram of a phase-locked loop designed based on a fractional-order extended state observer in an embodiment of the present invention.

[0015] Figure 4 This is a system block diagram of a sensorless control method for a permanent magnet synchronous motor in an embodiment of the present invention.

[0016] Figure 5 The graphs show the estimated speed, speed estimation error (speed error), and current estimation error (current error) of the three sliding mode observers when the expected rotational speed is 200 rpm in the embodiments of the present invention.

[0017] Figure 6 The graphs show the estimated speed, speed estimation error, and current estimation error of the three sliding mode observers when the expected rotational speed is 600 rpm in the embodiments of the present invention.

[0018] Figure 7 The graphs show the estimated speed, speed estimation error, and current estimation error of the three sliding mode observers when the expected rotational speed is 1000 rpm in the embodiments of the present invention.

[0019] Figure 8 This is a graph showing the estimated speed, speed estimation error, and position estimation error (i.e., position error) of the two phase-locked loops when the expected rotational speed is 200 rpm in an embodiment of the present invention.

[0020] Figure 9 This is a graph showing the estimated speed, speed estimation error, and position estimation error of the two phase-locked loops when the expected rotational speed is 600 rpm in an embodiment of the present invention.

[0021] Figure 10 This is a graph showing the estimated speed, speed estimation error, and position estimation error of the two phase-locked loops when the expected rotational speed is 1000 rpm in an embodiment of the present invention.

[0022] Figure 11 In this embodiment of the invention, when the desired rotational speed is 200 rpm, a sudden increase of 2... After the load speed is adjusted, the position error and current curves are obtained using the control method of this invention.

[0023] Figure 12In this embodiment of the invention, when the desired rotational speed is 1000 rpm, a sudden increase of 2... After the load speed is adjusted, the position error and current curves are obtained using the control method of this invention.

[0024] Figure 13 This is a graph showing the speed error and position error obtained by using the control method of this invention when the desired rotational speed is 200 rpm, after changing the rotational speed of the stator inductance and stator resistance.

[0025] Figure 14 This is a graph showing the speed error and position error obtained by using the control method of this invention when the desired rotational speed is 600 rpm, after changing the rotational speed of the stator inductance and stator resistance.

[0026] Figure 15 This is a graph showing the speed error and position error obtained by using the control method of this invention when the desired rotational speed is 1000 rpm, after changing the rotational speed of the stator inductance and stator resistance. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Example 1 This embodiment describes a sensorless control method for a permanent magnet synchronous motor (PMSM). Specifically, this method is a sensorless control method for a PMSM based on a fractional-order high-order sliding mode observer and an improved phase-locked loop based on a fractional-order extended state observer. The general idea is as follows: First, in... In a two-phase stationary coordinate system, a mathematical model of the back electromotive force (EMF) of a permanent magnet synchronous motor is established. Secondly, to suppress chattering in traditional sliding mode observers and improve the observer's estimation accuracy, thereby enhancing the system's accuracy in estimating rotor speed, this invention introduces fractional-order theory and a higher-order sliding mode control method, designing a fractional-order higher-order sliding mode observer to accurately estimate the motor's back EMF. Then, due to the advantages of the extended state observer—fast convergence, no need for a precise mathematical model, and ability to estimate unknown disturbances—this invention also designs a phase-locked loop (PLL) based on the fractional-order extended state observer to accurately extract the motor's speed and position, further improving the system's accuracy in estimating rotor position and speed. Finally, experimental results in this embodiment demonstrate that the sensorless control method for permanent magnet synchronous motors proposed in this invention not only effectively improves the estimation accuracy of rotor position and speed but also ensures strong robustness of the system under load disturbances and parameter mismatches.

[0028] The following describes the detailed steps of the sensorless control method for permanent magnet synchronous motors proposed in this invention.

[0029] like Figure 1 As shown, the sensorless control method for permanent magnet synchronous motors includes the following steps: Step 1. In A mathematical model of the back electromotive force of a permanent magnet synchronous motor is established in a two-phase stationary coordinate system.

[0030] exist In the two-phase stationary coordinate system, a mathematical model of the back electromotive force of the permanent magnet synchronous motor is established as shown in formula (1): (1) in, , In the two-phase stationary coordinate system respectively axis, Stator voltage of the shaft. This is the stator resistance. , In the two-phase stationary coordinate system respectively axis, Stator current of the shaft. It is the stator inductor. Indicates time. , They are respectively The back electromotive force of the motor in the two-phase stationary coordinate system of the shaft, and satisfying: (2) in, It is a permanent magnet flux linkage. This indicates the electric angular velocity of the motor. This indicates the electrical angle of the motor.

[0031] Step 2. Design a fractional-order sliding surface, i.e., design a fractional-order sliding surface.

[0032] Fractional calculus is a generalization of integer calculus. Compared to integer-order control, fractional-order control provides an additional degree of freedom, offering more flexibility and control options compared to traditional integer-order controllers.

[0033] Continuous fractional calculus operators Represented as: (3) in, This represents a fractional operator. It indicates the fractional order. This is the lower limit of integration. This is the upper limit of the integral. This represents the integral variable. express The real part.

[0034] This invention introduces the Caputo fractional algorithm, which is defined as follows: (4) in, It is an integer and satisfies . Represents the function f pair The m-th derivative. This represents the gamma function.

[0035] Gamma function Represented as: (5) The mathematical model of the back electromotive force of the permanent magnet synchronous motor in formula (1) is rewritten as follows: (6) in, For motor and shaft current, For motor and shaft voltage, For motor and Axis back electromotive force.

[0036] Current estimation error Represented as: (7) in, Indicates the estimated motor and Axis current.

[0037] To suppress chattering caused by high-frequency switching of the sign function in traditional sliding mode observers and improve the estimation accuracy of rotor position and velocity, this invention designs a fractional-order sliding surface. The designed fractional-order sliding surface... Specifically: (8) in, Represents a fractional operator. , , , , , It is a constant.

[0038] and , , , , , .

[0039] Step 3. Based on the mathematical model of the back EMF of the permanent magnet synchronous motor and the fractional sliding mode surface, design a high-order sliding mode observer based on the fractional order to estimate the back EMF of the motor.

[0040] Traditional sliding mode observers suffer from chattering due to high-frequency switching of the sign function. To suppress chattering and improve the estimation accuracy of the observer, thereby improving the system's estimation accuracy of rotor speed, this invention proposes a high-order sliding mode observer based on fractional order.

[0041] Specifically, in this embodiment, based on the fractional-order sliding surface designed in step 2, a higher-order sliding observer based on the fractional-order surface is designed by introducing fractional-order theory and higher-order sliding methods: (9) in, Indicates an intermediate variable. It is a constant, and The block diagram of the fractional-order high-order sliding mode observer designed in this embodiment is as follows: Figure 2 As shown.

[0042] Furthermore, in step 3 of this embodiment, after completing the design of the high-order sliding mode observer based on fractional order, a stability analysis is also performed on the permanent magnet synchronous motor system controlled by the high-order sliding mode observer shown in formula (9). The specific process is as follows: To demonstrate the stability of the fractional-order high-order sliding mode observer designed using the method of this invention, a Lyapunov function is selected. for: ,but: (10) Subtracting equation (9) from equation (6), we obtain the dynamic equation for the current estimation error as follows: (11) Substituting formula (11) into formula (8), we get: (12) Differentiating formula (12), we get: (13) According to formula (12), formula (10) can be expressed as: (14) Assume the upper bound of the current error differential is ,but: (15) in, Indicates motor Shaft current estimation error, Indicates motor Shaft current estimation error. Therefore, we obtain: (16) Therefore, the stability condition for a higher-order sliding mode observer based on fractional order is: .

[0043] Will Substituting into formula (12), the estimated back electromotive force of the motor in the high-order sliding mode observer is expressed as: (17) Step 4. Establish a dynamic model of the permanent magnet synchronous motor with parameter uncertainties.

[0044] Establish a dynamic model of a permanent magnet synchronous motor with parameter uncertainties as shown in equation (18): (18) in, This represents the q-axis current of the motor. Indicates the motor load torque. , , This refers to the parameter uncertainty.

[0045] , , .

[0046] in, Indicates the number of pole pairs of the motor. Indicates the moment of inertia of the motor. This represents the coefficient of friction of the motor.

[0047] Define the total disturbance of the system for: (19) in, This indicates the reference value for the q-axis current of the motor.

[0048] Substituting formula (19) into formula (18), we get: (20) The system extension equation can be established from formula (18) as follows: (twenty one) in, It represents a bounded, uncertain function.

[0049] Step 5. Based on the dynamic model of the permanent magnet synchronous motor with parameter uncertainties, a phase-locked loop is designed based on a fractional-order extended state observer and used to estimate the motor speed and position.

[0050] To further reduce estimation errors and ensure the dynamic performance of the system, the method of this invention also uses a fractional-order extended state observer to replace the PI (proportional-integral) regulator in the traditional phase-locked loop (PLL) to improve the accuracy of motor speed and position estimation. A PLL based on the fractional-order extended state observer is designed, and its schematic diagram is shown below. Figure 3 As shown, where Indicates the estimated motor Shaft back electromotive force, Indicates the estimated motor Axis back electromotive force.

[0051] Extended state observers offer advantages such as fast convergence, no need for precise mathematical models, and the ability to estimate unknown disturbances. To achieve accurate estimation of rotor position and speed, this invention designs a phase-locked loop (PLL) based on a fractional-order extended state observer to extract motor speed and position, replacing the traditional PLL and improving system performance.

[0052] Specifically, based on the dynamic model of a permanent magnet synchronous motor with parameter uncertainties, a phase-locked loop as shown in equation (22) is designed based on a fractional-order extended state observer: (twenty two) in, This represents the estimated electrical angle of the motor. This represents the estimated electrical angular velocity of the motor. It is an intermediate variable. , , This represents the observer gain. Represents a constant. .

[0053] Step 6. Using the high-order sliding mode observer designed in Step 3 and the phase-locked loop designed in Step 5, perform sensorless control of the permanent magnet synchronous motor system.

[0054] like Figure 4 A system block diagram of a sensorless control method for permanent magnet synchronous motors is shown. This invention uses a high-order sliding mode observer based on fractional order and a phase-locked loop based on a fractional-order extended state observer to achieve sensorless control of the permanent magnet synchronous motor system. Figure 4 middle Indicates the preset speed of the motor. Indicates speed error, Indicates the estimated speed. This indicates the preset d-axis reference current. This represents the actual current along the d-axis of the motor. Indicates the q-axis reference voltage. Indicates the d-axis reference voltage. Indicates the output pulse signal. Indicates DC voltage. The coordinate systems are represented by the direct axis and the quadrature axis. SVPWM represents space vector pulse width modulation, and PMSM represents permanent magnet synchronous motor.

[0055] according to Figure 4 It can be seen that the method of the present invention uses the high-order sliding mode observer based on fractional order designed in step 3 to estimate the back electromotive force in the motor, and uses the phase-locked loop based on the fractional-order extended state observer designed in step 5 to extract the rotor position and speed information contained in the back electromotive force. That is, the phase-locked loop based on the fractional-order extended state observer is used to estimate the motor speed and position. In this embodiment, the speed loop adopts the PI control algorithm. The d-axis uses... =0 control to ensure constant magnetic flux.

[0056] To better verify the accuracy of the control method designed in this invention in estimating rotor position and speed, as well as its robustness under load disturbances and parameter mismatches, the fractional-order high-order sliding mode observer proposed in this invention is compared with the traditional sliding mode observer and the high-order sliding mode observer. The fractional-order extended state observer phase-locked loop proposed in this invention is also compared with the extended state observer phase-locked loop.

[0057] First, to verify the performance of the fractional-order high-order sliding mode observer proposed in this invention, measurements were taken at 200... 600 With 1000 Three sets of comparative experiments were set up. The first set used a traditional sliding mode observer. The second set used a higher-order sliding mode observer. The third set used the fractional-order higher-order sliding mode observer proposed in this invention. The rotor velocity and position information in the back electromotive force were extracted using a fractional-order extended state observer phase-locked loop.

[0058] Experiment 1 involved the motor running stably at 200... 600 1000 Experiments with different sliding mode observers.

[0059] The experimental results under the three different conditions are described below: The back electromotive force (EMF) is estimated using a traditional sliding mode observer, a higher-order sliding mode observer, and the fractional-order higher-order sliding mode observer proposed in this invention, respectively. Furthermore, a fractional-order extended state observer phase-locked loop is used to extract rotor position and velocity information from the back EMF. The estimated velocity, velocity error, and current error of different sliding mode observers are shown below. Figures 5 to 7 As shown.

[0060] like Figure 5 As shown, when the permanent magnet synchronous motor operates at the desired speed of 200... At that time, the maximum current estimation errors of the traditional sliding mode observer, the higher-order sliding mode observer, and the fractional-order higher-order sliding mode observer proposed in this invention are 3.4, respectively. 0.2 0.08 The speed error fluctuation was 21.4. 14.3 9.96 The estimated velocity fluctuations are 16.4. 4.3 2.9 .

[0061] like Figure 6 As shown, when the permanent magnet synchronous motor operates at the desired speed of 600... At that time, the maximum current estimation errors of the traditional sliding mode observer, the higher-order sliding mode observer, and the fractional-order higher-order sliding mode observer proposed in this invention are 3.6 and 3.6, respectively. 0.22 0.12 The speed error fluctuation was 14.2. 8.5 5 The estimated velocity fluctuations are 9.8. 2.6 1.6 .

[0062] like Figure 7 As shown, when the permanent magnet synchronous motor operates at the desired speed of 1000... At that time, the maximum current estimation errors of the traditional sliding mode observer, the higher-order sliding mode observer, and the fractional-order higher-order sliding mode observer proposed in this invention are 5.4, respectively. 0.34 0.22 The speed error fluctuation was 13.9. 9 5.7 The estimated velocity fluctuations are 9.3. 3.8 1.9 .

[0063] As can be seen from the results of Experiment 1 above, the sensorless control method for permanent magnet synchronous motors of the present invention can effectively suppress chattering and improve the estimation accuracy of rotor position and speed. The fractional-order high-order sliding mode observer proposed in this invention has the best estimation performance compared with traditional sliding mode observers and high-order sliding mode observers.

[0064] Secondly, to verify the performance of the fractional-order extended state observer phase-locked loop proposed in this invention, tests were conducted at 200... 600 With 1000 Three sets of comparative experiments were set up. The first set used a traditional extended state observer phase-locked loop (PLL). The second set used the fractional-order extended state observer PLL proposed in this invention. The fractional-order high-order sliding mode observer proposed in this invention was used to estimate the back electromotive force of the motor.

[0065] Experiment 2 involved the motor running stably at 200... 600 1000 Experiments with different phase-locked loops.

[0066] To verify the performance of the fractional-order extended state observer phase-locked loop proposed in this invention, a comparative experiment was conducted with a traditional extended state observer phase-locked loop in this embodiment. Simultaneously, the fractional-order high-order sliding mode observer proposed in this invention was used to estimate the motor back electromotive force, obtaining the estimated speed, speed estimation error, and position estimation error as follows: Figures 8 to 10 As shown.

[0067] like Figure 8 As shown, when the permanent magnet synchronous motor operates at the desired speed of 200... At that time, the velocity estimation error fluctuations of the traditional extended state observer phase-locked loop and the fractional-order extended state observer phase-locked loop proposed in this invention were 15.33%. 9.96 The position estimation error fluctuation was 0.08. 0.04 The estimated velocity fluctuations are 6.7. 2.9 .

[0068] like Figure 9 As shown, when the permanent magnet synchronous motor operates at the desired speed of 600... At that time, the velocity estimation error fluctuations of the traditional extended state observer phase-locked loop and the fractional-order extended state observer phase-locked loop proposed in this invention were 11.2%. 5 The position estimation error fluctuation was 0.06%. 0.027 The estimated velocity fluctuations are 5.8. 1.6 .

[0069] like Figure 10 As shown, when the permanent magnet synchronous motor operates at the desired speed of 1000... At that time, the velocity estimation error fluctuations of the traditional extended state observer phase-locked loop and the fractional-order extended state observer phase-locked loop proposed in this invention were 11.3%. 5.7 The position estimation error fluctuation was 0.054. 0.035 The estimated velocity fluctuations are 3.3. 1.9 .

[0070] The results of Experiment 2 above show that the fractional-order extended state observer phase-locked loop proposed in this invention has good accuracy in estimating rotor position and velocity.

[0071] To verify the disturbance rejection performance of the proposed sensorless permanent magnet synchronous motor control method, a sudden load application experiment was also designed in this embodiment. During the experiment, the load torque suddenly changed from 0 to 2. It becomes 0 again after 5 seconds. .

[0072] Experiment 3 is a sudden load test.

[0073] Figure 11 and Figure 12 The following are given for permanent magnet synchronous motors operating at a desired speed of 200. and 1000 Results of a sudden load application experiment. Specifically, during the experiment, the load torque suddenly changed from 0 to 2. It becomes 0 again after 5 seconds. .

[0074] At the desired speed of 200 At that time, the speed fluctuations of the permanent magnet synchronous motor system using the control method of this invention during loading and unloading were 71. and 61 The adjustment times were 0.21s and 0.25s, respectively.

[0075] At the desired speed of 1000 At that time, the speed fluctuations of the permanent magnet synchronous motor system using the control method of this invention during loading and unloading were 74. and 71 The adjustment times were 0.84s and 0.78s, respectively.

[0076] The results of Experiment 3 above show that when a sudden load disturbance is applied, the sensorless control method for permanent magnet synchronous motors can still accurately estimate the rotor position and speed information, and has good resistance to load disturbances.

[0077] Finally, parameters such as stator resistance and stator inductance of the permanent magnet synchronous motor inevitably change. Mismatches in these parameters will lead to reduced rotor position estimation accuracy, thereby degrading the overall system performance. To verify the robustness of the permanent magnet synchronous motor system controlled by the method of this invention under conditions of parameter uncertainty, experiments were conducted with stator inductance and resistance mismatched, with the stator inductance and resistance at a range of 0.5... Up to 1.5 Variations within the range.

[0078] Experiment 4 is a variable parameter experiment.

[0079] Figures 13 to 15 The sensorless control method for permanent magnet synchronous motors using the present invention was demonstrated in 200 600rpm, 1000 At the desired rotational speed, after changing the rotational speed of the stator inductance and stator resistance, i.e., when the stator inductance and stator resistance are at 0.5... Up to 1.5 The experimental results show the changes between them. Based on... Figures 13 to 15 It can be seen that when the stator inductance and stator resistance change, the sensorless control method for permanent magnet synchronous motors of the present invention can still maintain a small speed fluctuation in the permanent magnet synchronous motor system and still have high rotor position and speed tracking accuracy.

[0080] The results of Experiment 4 above demonstrate that the sensorless control method for permanent magnet synchronous motors of the present invention has strong robustness in dealing with parameter mismatch.

[0081] The above four sets of experimental results demonstrate that the sensorless control method for permanent magnet synchronous motors proposed in this invention can not only effectively improve the accuracy of rotor position and speed estimation, but also ensure that the system has strong robustness under load disturbances and parameter mismatches.

[0082] This embodiment introduces the concept of fractional calculus, then designs a fractional sliding surface, and subsequently designs a higher-order fractional sliding observer. The higher-order fractional sliding observer proposed in this invention can effectively suppress chattering in the sliding mode, improve the estimation accuracy of the observer, and thus improve the system's estimation accuracy of motor speed.

[0083] Phase-locked loops (PLLs) are commonly used to extract rotor position and velocity information from back electromotive force (EMF). However, traditional PLLs suffer from poor estimation accuracy. Extended state observers (ESAs) offer advantages such as fast convergence, no need for precise mathematical models, and the ability to estimate unknown disturbances. To improve the system's estimation accuracy of rotor position and velocity while ensuring strong robustness under load disturbances and parameter mismatches, this invention designs a PLL based on a fractional-order extended state observer. Unlike existing fractional-order extended state observer designs, which are typically used to estimate disturbances in the system, the proposed method uses a PLL based on a fractional-order extended state observer to extract motor speed and position information, thereby improving the system's estimation accuracy.

[0084] The method of this invention, based on the principle of vector control, not only improves the high-precision estimation of rotor position and rotor speed of the sensorless permanent magnet synchronous motor system, but also ensures that the system has strong robustness under load disturbances and parameter mismatches.

[0085] Example 2 This embodiment 2 describes a sensorless control system for a permanent magnet synchronous motor, which is based on the same inventive concept as the sensorless control method for a permanent magnet synchronous motor in embodiment 1.

[0086] Specifically, the sensorless control system for this permanent magnet synchronous motor includes the following modules: Model building module, used in A mathematical model of the back electromotive force of a permanent magnet synchronous motor is established in a two-phase stationary coordinate system.

[0087] The sliding surface design module is used to design fractional sliding surfaces.

[0088] The observer design module is used to design a high-order sliding mode observer based on the fractional-order sliding mode surface, based on the mathematical model of the back EMF of the permanent magnet synchronous motor, so as to realize the estimation of the back EMF of the motor.

[0089] The dynamic model building module is used to establish a dynamic model of a permanent magnet synchronous motor with parameter uncertainties.

[0090] The phase-locked loop (PLL) design module is used to design a PLL based on a fractional-order extended state observer on a dynamic model of a permanent magnet synchronous motor with parameter uncertainties, and to use it to estimate the motor speed and position.

[0091] And a sensorless control module for sensorless control of permanent magnet synchronous motor systems using a high-order sliding mode observer and a phase-locked loop.

[0092] It should be noted that the implementation process of the functions and roles of each functional module in the sensorless control system for permanent magnet synchronous motors is detailed in the implementation process of the corresponding steps in the method of Example 1, and will not be repeated here.

[0093] Example 3 This embodiment 3 describes a computer device that includes a memory and one or more processors.

[0094] The memory stores executable code, which, when executed by the processor, is used to implement the steps of the sensorless control method for permanent magnet synchronous motors in Embodiment 1 above.

[0095] In this embodiment, the computer device can be any device or apparatus with data processing capabilities, and will not be described in detail here.

[0096] Example 4 This embodiment 4 describes a computer-readable storage medium storing a program that, when executed by a processor, implements the steps of a sensorless control method for a permanent magnet synchronous motor.

[0097] The computer-readable storage medium can be an internal storage unit of any device or apparatus with data processing capabilities, such as a hard disk or memory, or an external storage device of any device with data processing capabilities, such as a plug-in hard disk, smart media card (SMC), SD card, flash card, etc.

[0098] Of course, the above description is only a preferred embodiment of the present invention. The present invention is not limited to the above-described embodiments. It should be noted that any equivalent substitutions or obvious modifications made by those skilled in the art under the guidance of this specification fall within the scope of this specification and should be protected by the present invention.

Claims

1. A sensorless control method for a permanent magnet synchronous motor, characterized in that, Includes the following steps: Step 1. In A mathematical model of the back electromotive force of a permanent magnet synchronous motor is established in a two-phase stationary coordinate system. Step 2. Design the fractional-order sliding surface; Step 3. Based on the mathematical model of the back EMF of the permanent magnet synchronous motor and the fractional sliding mode surface, design a high-order sliding mode observer based on the fractional order to estimate the back EMF of the motor; Step 4. Establish a dynamic model of the permanent magnet synchronous motor with parameter uncertainties; Step 5. Based on the dynamic model of the permanent magnet synchronous motor with parameter uncertainties, a phase-locked loop is designed based on a fractional-order extended state observer and used to estimate the motor speed and position; Step 6. Using the high-order sliding mode observer from Step 3 and the phase-locked loop from Step 5, perform sensorless control of the permanent magnet synchronous motor system.

2. The sensorless control method for a permanent magnet synchronous motor according to claim 1, characterized in that, Step 1 specifically involves: exist In the two-phase stationary coordinate system, a mathematical model of the back electromotive force of the permanent magnet synchronous motor is established as shown in formula (1): (1) in, , In the two-phase stationary coordinate system respectively axis, Stator voltage of the shaft; Stator resistance; , In the two-phase stationary coordinate system respectively axis, Stator current of the shaft; For stator inductance; Indicates time; , They are respectively The back electromotive force of the motor in the two-phase stationary coordinate system of the shaft, and satisfying: (2) in, For permanent magnet flux linkage; This indicates the electric angular velocity of the motor; This indicates the electrical angle of the motor.

3. The sensorless control method for a permanent magnet synchronous motor according to claim 2, characterized in that, Step 2 specifically involves: Continuous fractional calculus operators Represented as: (3) in, Represents a fractional operator; Indicates the order of a fraction; This is the lower limit of the integral; Represents the integral variable; express The real part; Introducing the Caputo fractional algorithm, it is defined as follows: (4) in, It is an integer and satisfies ; Represents the function f pair The m-th derivative; Represents the gamma function; Gamma function Represented as: (5) The mathematical model of the back electromotive force of the permanent magnet synchronous motor in formula (1) is rewritten as follows: (6) in, For motor and shaft current; For motor and Shaft voltage; For motor and Shaft back electromotive force; Current estimation error Represented as: (7) in, Indicates the estimated motor and shaft current; Design of fractional sliding surfaces for: (8) in, Represents a fractional operator; , , , , , It is a constant; and , , , , , .

4. The sensorless control method for a permanent magnet synchronous motor according to claim 3, characterized in that, Step 3 specifically involves: Based on the mathematical model of the back electromotive force of the permanent magnet synchronous motor established in step 1 and the fractional-order sliding surface designed in step 2, a higher-order sliding mode observer based on the fractional order is designed as follows: (9) in, Indicates intermediate variables; It is a constant, and .

5. The sensorless control method for a permanent magnet synchronous motor according to claim 4, characterized in that, In step 3, after completing the design of the fractional-order high-order sliding mode observer, a stability analysis is performed on the permanent magnet synchronous motor system controlled by the high-order sliding mode observer shown in formula (9). The specific process is as follows: Choose the Lyapunov function for: ,but: (10) Subtracting equation (9) from equation (6), we obtain the dynamic equation for the current estimation error as follows: (11) Substituting formula (11) into formula (8), we get: (12) Differentiating formula (12), we get: (13) According to formula (12), formula (10) can be expressed as: (14) Let the upper bound of the differential of the current error be ,but: (15) in, Indicates motor Shaft current estimation error; Indicates motor Shaft current estimation error; thus, we obtain: (16) The stability condition for a higher-order sliding mode observer based on fractional order is: ； Will Substituting into formula (12), the estimated back electromotive force of the motor in the high-order sliding mode observer is expressed as: (17)。 6. The sensorless control method for a permanent magnet synchronous motor according to claim 5, characterized in that, Step 4 specifically involves: Establish a dynamic model of a permanent magnet synchronous motor with parameter uncertainties as shown in equation (18): (18) in, This represents the q-axis current of the motor; Indicates the motor load torque; , , For parameter uncertainty; ， ， ； in, Indicates the number of pole pairs of the motor; This represents the moment of inertia of the motor. This represents the coefficient of friction of the motor; Define the total disturbance of the system for: (19) in, This indicates the reference value for the q-axis current of the motor; Substituting formula (19) into formula (18), we get: (20) The system extension equation can be established from formula (18) as follows: (21) in, It represents a bounded, uncertain function.

7. The sensorless control method for a permanent magnet synchronous motor according to claim 6, characterized in that, Step 5 specifically involves: Based on the dynamic model of a permanent magnet synchronous motor with parameter uncertainties, a phase-locked loop as shown in equation (22) is designed using a fractional-order extended state observer: (22) in, This represents the estimated electrical angle of the motor; This represents the estimated electrical angular velocity of the motor; As an intermediate variable; , , Indicates the observer gain; Represents a constant. .

8. A sensorless control system for a permanent magnet synchronous motor, characterized in that, include: Model building module, used in A mathematical model of the back electromotive force of a permanent magnet synchronous motor is established in a two-phase stationary coordinate system. The sliding surface design module is used to design fractional-order sliding surfaces; The observer design module is used to design a high-order sliding mode observer based on the fractional-order sliding mode surface, based on the mathematical model of the back EMF of the permanent magnet synchronous motor, so as to realize the estimation of the back EMF of the motor. The dynamic model building module is used to establish a dynamic model of a permanent magnet synchronous motor with parameter uncertainties. The phase-locked loop design module is used to design a phase-locked loop based on a fractional-order extended state observer on the basis of a dynamic model of a permanent magnet synchronous motor with parameter uncertainties, and to use it to estimate the motor speed and position. And a sensorless control module for sensorless control of permanent magnet synchronous motor systems using a high-order sliding mode observer and a phase-locked loop.

9. A computer device comprising a memory and one or more processors, wherein the memory stores executable code, characterized in that, When the processor executes the executable code, it implements the steps of the sensorless control method for permanent magnet synchronous motors as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the sensorless control method for permanent magnet synchronous motors as described in any one of claims 1 to 7.

Images