Sensorless permanent magnet synchronous motor control method based on second-order STO

Abstract

The invention provides a sensorless permanent magnet synchronous motor control method based on a second-order STO, and relates to the technical field of motor control, and the method comprises the steps: designing a second-order superspiral sliding mode observer under an alpha-beta static coordinate system, dynamically estimating the counter electromotive force through double-gain adjustment and current error, and obtaining a second-order superspiral sliding mode observer; the high-precision extraction of the rotor position and the rotating speed is realized; the back electromotive force dynamic error and the load disturbance estimation of the sliding mode disturbance observer are fused to generate a total disturbance compensation item, and the anti-interference capability of the system is improved; a rotating speed outer ring controller is designed in combination with a non-singular fast terminal sliding mode surface and an adaptive variable speed reaching law, and a sign function is replaced by a saturation function, so that the jitter amplitude is reduced, the dynamic response time is shortened, and the system robustness is improved. The method is suitable for high-precision speed regulation scenes such as new energy driving and industrial automation.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a sensorless permanent magnet synchronous motor control method based on a second-order STO (Super-Twisting Observer). Background Art

[0002] In recent years, with the continuous intensification of the energy crisis, photovoltaic power generation technology, wind power generation technology, and new energy electric vehicle technology have all developed vigorously. Compared with asynchronous motors, permanent magnet synchronous motors (PMSMs) have many advantages such as high power density and high efficiency, and are therefore widely used in wind power generation systems and new energy electric vehicle drive systems.

[0003] In a vector control system, the rotor position information of a permanent magnet synchronous motor is the basis for realizing torque and flux decoupling control. Conventional methods often obtain the rotor position information by installing devices such as encoders on the motor. However, in wind power generation systems and new energy electric vehicles, the operating environment of permanent magnet synchronous motors is usually relatively harsh, and environmental factors such as vibration, humidity, and low temperature often cause faults such as encoder wire breakage and pulse signal loss, which in turn lead to the failure of the vector control system, resulting in problems such as high hardware costs, increased system complexity, and poor environmental adaptability.

[0004] Most of the existing sensorless technologies are based on a sliding mode observer (SMO), but the traditional first-order sliding mode observer has defects such as severe chattering, slow dynamic response, and insufficient back electromotive force estimation accuracy. In addition, load disturbances and parameter uncertainties further affect the system robustness. Summary of the Invention

[0005] Therefore, an embodiment of the present invention provides a sensorless permanent magnet synchronous motor control method based on a second-order STO, which is used to solve the problems such as high cost, severe chattering, and insufficient anti-interference ability caused by traditional control relying on position sensors in the prior art.

[0006] To solve the above problems, an embodiment of the present invention provides a sensorless permanent magnet synchronous motor control method based on a second-order STO, the method comprising:

[0007] Construct a stator current dynamic equation of the permanent magnet synchronous motor in the α-β stationary coordinate system;

[0008] Design a second-order super-twisting sliding mode observer based on the stator current dynamic equation, dynamically estimate the back electromotive force through the current error, and extract the rotor position and speed based on the back electromotive force;

[0009] Fuse the back electromotive force dynamic error of the second-order super-twisting sliding mode observer and the load disturbance estimation value of the sliding mode disturbance observer to generate a total disturbance compensation term;

[0010] Design a speed outer-loop controller using a non-singular fast terminal sliding mode surface and an adaptive variable-speed reaching law, and generate a control signal in combination with the total disturbance compensation term;

[0011] Transmit the control signal to the inverter to drive the permanent magnet synchronous motor to operate.

[0012] Preferably, the mathematical model of the second-order super-twisting sliding mode observer is:

[0013]

[0014] In the formula, respectively represent the first derivatives of the estimated values of the α-axis and β-axis components of the stator current in the α-β stationary coordinate system; i α , i β respectively represent the α-axis and β-axis components of the stator current in the α-β stationary coordinate system; L represents the inductance of the stator winding of the permanent magnet synchronous motor; R s represents the resistance of the stator winding of the permanent magnet synchronous motor; u α , u β respectively represent the α-axis and β-axis components of the stator voltage in the α-β stationary coordinate system; λ1, λ2 > 0 are the gains of the second-order super-twisting sliding mode observer; e i represents the current error, that is, the difference between the actual current i α,β and the estimated current ; sign(·) is the sign function; z1 is an intermediate variable in the second-order super-twisting sliding mode observer, and its first derivative is determined by λ2sign(e i ).

[0015] Preferably, the generation of the total disturbance compensation term includes:

[0016] Estimate the load disturbance through the sliding mode disturbance observer

[0017] Extract the back electromotive force dynamic error through the second-order super-twisting observer

[0018] The total disturbance compensation term is

[0019] Preferably, the adaptive variable-speed reaching law is:

[0020]

[0021] In the formula, is the first derivative of the sliding mode surface \(s\) with respect to time, reflecting the rate of change of the sliding mode surface state over time; \(k\), \(\varepsilon\), \(c\), \(a\), \(b\) are all gains to be designed; \(sat(s)\) is the saturation function.

[0022] Preferably, the expression of the saturation function is:

[0023]

[0024] where \(\Delta\) e is the boundary layer thickness.

[0025] Preferably, the expression of the speed outer loop controller is:

[0026]

[0027] where \(u\) represents the control signal output by the speed outer loop controller; \(s\) is the sliding mode surface, \(k\), \(\varepsilon\), \(c\), \(a\), \(b\), \(g\) are all gains to be designed; \(sat(s)\) is the saturation function; \(x1\), \(x2\) are state variables; \(\gamma\), \(\mu\), \(p\), \(q\), \(h\) are all coefficients to be designed; is the total disturbance compensation term; \(k2\) is the disturbance compensation gain coefficient; \(D\) is the denominator coefficient.

[0028] Preferably, the control function of the sliding mode disturbance observer is:

[0029]

[0030] where \(u\) smo is the control function of the sliding mode disturbance observer; \(s1\) is the sliding mode surface; \(sat(s)\) is the saturation function; \(\varepsilon1\), \(\varepsilon2\) are coefficients to be designed; \(B\) is the viscous friction coefficient of the motor; \(J\) is the moment of inertia of the motor; \(e\) ω is the error between the actual speed and the observed speed.

[0031] The embodiment of the present invention also provides a sensorless permanent magnet synchronous motor control system based on a second-order STO, which is used to implement the sensorless permanent magnet synchronous motor control method based on the second-order STO described above, and specifically includes:

[0032] A stator current dynamic equation construction module, configured to construct a stator current dynamic equation of a permanent magnet synchronous motor in the \(\alpha - \beta\) stationary coordinate system;

[0033] A second-order super-twisting sliding mode observer design module, configured to design a second-order super-twisting sliding mode observer based on the stator current dynamic equation, dynamically estimate the back electromotive force through the current error, and extract the rotor position and speed based on the back electromotive force;

[0034] The total disturbance compensation term generation module is used to fuse the back electromotive force dynamic error of the second-order super-twisting sliding mode observer and the load disturbance estimation value of the sliding mode disturbance observer to generate a total disturbance compensation term;

[0035] The speed outer loop controller design module is used to design a speed outer loop controller by using a non-singular fast terminal sliding mode surface and an adaptive variable speed reaching law, and generate a control signal in combination with the total disturbance compensation term;

[0036] The motor drive module is used to transmit the control signal to the inverter to drive the permanent magnet synchronous motor to operate.

[0037] An embodiment of the present invention also provides an electronic device, which includes a processor, a memory, and a bus system. The processor and the memory are connected through the bus system. The memory is used to store instructions, and the processor is used to execute the instructions stored in the memory to implement the above-mentioned sensorless permanent magnet synchronous motor control method based on the second-order STO.

[0038] An embodiment of the present invention also provides a computer storage medium, which stores a computer software product. The computer software product includes several instructions for enabling a computer device to execute the above-mentioned sensorless permanent magnet synchronous motor control method based on the second-order STO.

[0039] As can be seen from the above technical solutions, the present invention application has the following beneficial effects:

[0040] (1) High-precision rotor position and speed estimation: Design a second-order super-twisting sliding mode observer in the α-β stationary coordinate system, and estimate the back electromotive force by means of double gain adjustment and current error dynamics. This design can effectively eliminate the chattering problem of the traditional sliding mode, realize high-precision rotor position and speed estimation without a position sensor, and improve the estimation accuracy of the back electromotive force.

[0041] (2) Good dynamic performance: Integrate the adaptive variable speed reaching law and the non-singular terminal sliding mode. Use the saturation function to replace the sign function, which not only reduces the chattering amplitude, but also shortens the dynamic response time, and at the same time reduces the overshoot. The system can reach the stable state more quickly and smoothly, improving the overall dynamic performance of the system.

[0042] (3) Strong anti-interference ability: Integrate the back electromotive force dynamic error of the second-order super-twisting sliding mode observer (STO) and the load disturbance estimation of the sliding mode disturbance observer (SMO), reducing the total disturbance compensation error. This enables the system to significantly reduce the speed fluctuation when facing disturbances such as sudden load addition, effectively improving the anti-interference ability of the system. In addition, the hardware structure is simplified and the cost is reduced, which is applicable to complex working condition scenarios such as electric vehicles and wind power pitch control. Description of the Drawings

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly describe the drawings required in the embodiments. By referring to the drawings, the features and advantages of the present invention will be more clearly understood. The drawings are schematic and should not be construed as imposing any limitations on the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them:

[0044] Figure 1 It is a flowchart of a sensorless permanent magnet synchronous motor control method based on second-order STO provided by the present invention;

[0045] Figure 2 It is a control block diagram of the permanent magnet synchronous motor system in the embodiment;

[0046] Figure 3 It is a block diagram of a sensorless permanent magnet synchronous motor control system based on second-order STO provided by the present invention. Specific embodiments

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0048] Embodiment 1

[0049] Aiming at the problems of high cost, serious chattering, and insufficient anti-interference ability caused by the traditional control relying on position sensors, as Figure 1 shown, the present invention proposes a sensorless permanent magnet synchronous motor control method based on second-order STO, and the method includes:

[0050] S1: In the α-β stationary coordinate system, construct the stator current dynamic equation of the permanent magnet synchronous motor;

[0051] S2: Design a second-order super-twisting sliding mode observer based on the stator current dynamic equation, dynamically estimate the back electromotive force through the current error, and extract the rotor position and speed based on the back electromotive force;

[0052] S3: Fuse the back electromotive force dynamic error of the second-order super-twisting sliding mode observer and the load disturbance estimation value of the sliding mode disturbance observer to generate a total disturbance compensation term;

[0053] S4: Design a speed outer - loop controller using a nonsingular fast terminal sliding - mode surface and an adaptive variable - speed reaching law, and generate a control signal by combining the total disturbance compensation term;

[0054] S5: Transmit the control signal to the inverter to drive the permanent - magnet synchronous motor to operate.

[0055] As can be seen from the above technical solutions, the present invention proposes a sensorless control method for a permanent - magnet synchronous motor based on a second - order STO. A stator - current dynamic equation is constructed in the α - β stationary coordinate system. Accordingly, a second - order super - twisting sliding - mode observer is designed. The back - electromotive force is estimated through the current error, and then the rotor position and speed are extracted to achieve high - precision sensorless estimation. At the same time, the total disturbance compensation term is generated by fusing the dynamic error of the back - electromotive force of the observer and the load - disturbance estimation value of the sliding - mode disturbance observer to improve the anti - interference ability of the system. In addition, a speed outer - loop controller is designed using a nonsingular fast terminal sliding - mode surface and an adaptive variable - speed reaching law, and a control signal is generated by combining the total disturbance compensation term to drive the motor. This scheme has significant advantages, eliminating the traditional sliding - mode chattering, shortening the dynamic response time, reducing the overshoot, reducing the speed fluctuation when suddenly applying a load, improving the anti - interference ability of the system, and also simplifying the hardware structure and reducing costs, which is applicable to complex working conditions such as electric vehicles and wind - power pitch control.

[0056] In this embodiment, first, in the α - β stationary coordinate system, a stator - current dynamic equation of a permanent - magnet synchronous motor (PMSM) is constructed.

[0057] In step S2, a second - order super - twisting sliding - mode observer is designed based on the stator - current dynamic equation of the PMSM. The back - electromotive force is dynamically estimated through the current error, and the rotor position and speed are extracted based on the normalization of the back - electromotive force. The mathematical model of the second - order super - twisting sliding - mode observer is as follows:

[0058]

[0059] In the formula, respectively represent the first - order derivatives of the estimated values of the α - axis and β - axis components of the stator current in the α - β stationary coordinate system; i α , i β respectively represent the α - axis and β - axis components of the stator current in the α - β stationary coordinate system; L represents the inductance of the stator winding of the permanent - magnet synchronous motor; R s represents the resistance of the stator winding of the permanent - magnet synchronous motor; u α , u β respectively represent the α - axis and β - axis components of the stator voltage in the α - β stationary coordinate system; λ1, λ2>0 are the gains of the second - order super - twisting sliding - mode observer; e i represents the current error, that is, the actual current i α,β and the estimated current The difference between; sign(·) is the sign function; z1 is an intermediate variable in the second-order super-twisting sliding mode observer, and its first derivative is determined by λ2sign(e i ).

[0060] It has been experimentally verified that in the α-β stationary coordinate system, the present invention realizes the rapid convergence of the current error through double-gain adjustment, improving the back electromotive force estimation accuracy.

[0061] Furthermore, the estimated value of the back electromotive force is the rotor position and the rotational speed are extracted through back electromotive force normalization:

[0062]

[0063]

[0064] In step S3, the back electromotive force dynamic error of the second-order super-twisting sliding mode observer and the load disturbance estimation value of the sliding mode disturbance observer are fused to generate a total disturbance compensation term.

[0065] The back electromotive force dynamic error of the second-order STO is fused with the load disturbance estimation of the original sliding mode disturbance observer (SMO) , and the total disturbance compensation is:

[0066]

[0067] It has been experimentally verified that the present invention combines the back electromotive force error of the second-order STO with the load disturbance estimation of the SMO, reducing the total disturbance compensation error.

[0068] In order to enhance the control effect of the sliding mode speed controller and achieve compensation to a certain extent, according to the unknown disturbance part in the sliding mode speed controller, it is expanded into a state variable, and a sliding mode disturbance observer is designed.

[0069] The PMSM speed loop model is:

[0070]

[0071] Wherein, is the first derivative of the mechanical angular velocity ω of the motor m with respect to time t; n p is the number of pole pairs of the motor, referring to the number of pairs of magnetic poles on the motor rotor, ψ f is the permanent magnet flux linkage, J is the moment of inertia of the motor; B is the viscous friction coefficient of the motor; i q is the quadrature-axis current; T Lis the load torque; δ(t) is the unknown disturbance; is the change rate of the unknown disturbance.

[0072] Design a sliding mode disturbance observer according to formula (5):

[0073]

[0074] In the formula, is the estimated value of the rotational speed; is the total disturbance compensation term, is the first derivative of the total disturbance compensation term; u smo is the control function of the (to be designed) sliding mode disturbance observer; η is the gain to be designed, and η > 0.

[0075] Combining formulas (5) and (6) can obtain the observation error equation:

[0076]

[0077] In the formula, e ω is the error between the actual rotational speed and the observed rotational speed, and e δ is the error between the actual disturbance and the observed disturbance, and

[0078] Select the sliding mode surface s1:

[0079]

[0080] Select the exponential reaching law

[0081]

[0082] In the formula: ε1, ε2 are the coefficients to be designed, and ε1 > 0, ε2 > 0. And use the saturation function to replace the sign function:

[0083]

[0084] In the formula, Δ e is the boundary layer thickness.

[0085] Combining formulas (7), (8), and (9) can obtain the control function of the sliding mode disturbance observer:

[0086]

[0087] In the formula, u smo is the control function of the sliding mode disturbance observer; s1 is the sliding mode surface; sat(s) is the saturation function; ε1, ε2 are the coefficients to be designed; B is the viscous friction coefficient of the motor; J is the moment of inertia of the motor; e ωis the error between the actual speed and the observed speed.

[0088] In step S4, a non-singular fast terminal sliding mode surface and an adaptive variable speed reaching law are used to design the speed outer loop controller, and a control signal is generated by combining the total disturbance compensation term.

[0089] The traditional exponential reaching law is:

[0090]

[0091] where: ε is the constant speed term coefficient of the exponential reaching law, k is the exponential term coefficient of the exponential reaching law, and ε>0, k>0 are satisfied; s is the sliding mode surface.

[0092] The sign function in the traditional exponential reaching law is a non-linear function. Due to the characteristics of the sign function itself, chattering will be generated near the sliding mode surface, affecting the control effect. To improve the control effect and weaken the chattering, the present invention uses a saturation function to replace the sign function, and the saturation function is as shown in formula (10).

[0093] Verified by experiments, the present invention uses a saturation function to replace the sign function, which not only reduces the chattering amplitude but also shortens the dynamic response time.

[0094] Since normally when the coefficient of the exponential term increases, it is necessary to appropriately reduce the constant speed term coefficient to maintain the stability of the control in order to reduce the generation of chattering. However, due to the existence of the saturation function and the adaptive coefficient, the coefficients of the two reaching terms can be increased simultaneously within a certain range to ensure the stability and rapidity of convergence. The designed reaching law is as shown in formula (13):

[0095]

[0096] where is the first derivative of the sliding mode surface s with respect to time, reflecting the change rate of the sliding mode surface state with time; k, ε, c, a, b are all gains to be designed, and k>0, ε>0, c>0, -1 < a < 0, 0 < b < 1; sat(s) is the saturation function.

[0097] At the same time, in order to further weaken the chattering, accelerate the convergence speed, and reduce the singularity in the subsequent design of the controller, a non-singular fast terminal sliding mode surface is selected to be fused with this reaching law. The non-singular fast terminal sliding mode surface is as follows:

[0098]

[0099] where x1 and x2 are both state variables; γ, μ, p, q, h are coefficients to be designed, and γ, μ>0,

[0100] Furthermore, the design of the speed outer loop controller is as follows:

[0101] The speed outer loop of the permanent magnet synchronous motor speed regulation system is designed, and the traditional PI controller is adopted for the speed inner loop.

[0102] First, select the controller state variables:

[0103]

[0104] In the formula, ω * is the speed reference value; is the first derivative of the speed reference value ω * ; x1 and x2 are both state variables; is the first derivative of the state variable x1.

[0105] Then, taking the derivative of x2 gives:

[0106]

[0107] In the formula, is the first derivative of the state variable x2; is the second derivative of the speed reference value ω * ; is the second derivative of the motor mechanical angular velocity ω m ; is the first derivative of the load torque T L ; is the first derivative of the motor mechanical angular velocity ω m .

[0108] Next, when considering the unknown disturbance, rewrite the above formula as:

[0109]

[0110] In the formula, Δ1 and Δ2 are the uncertainty factors of the corresponding terms and fluctuate within a certain range; is the first derivative of the load torque.

[0111]

[0112] In the formula, is the change rate of the unknown disturbance and is bounded, satisfying ∑ is a positive constant.

[0113] Finally, according to formulas (14), (16), and (17), the system mathematical model is obtained as:

[0114]

[0115] Finally, the expression of the speed outer loop controller is:

[0116]

[0117] In the formula, u represents the control signal output by the outer speed loop controller; s is the sliding mode surface, and γ, μ, k, ε, c, a, b, g are all gains to be designed; sat(s) is the saturation function; x1 and x2 are both state variables; γ, μ, p, q, h are all coefficients to be designed; is the total disturbance compensation term; k2 is the disturbance compensation gain coefficient; D is the denominator coefficient,

[0118] In step S5, the control signal is transmitted to the inverter to drive the permanent magnet synchronous motor to operate.

[0119] As Figure 2 shown, this system is a sensorless control system for a permanent magnet synchronous motor (PMSM) based on a second-order super-twisting sliding mode observer (STSMO), and its control process is as follows:

[0120] (1) Signal acquisition: The sensor acquires the three-phase current i abc and the three-phase voltage U abc .

[0121] (2) Coordinate transformation: The acquired three-phase current i abc is converted into the current i α and i β in the two-phase stationary coordinate system through Clark transformation, and then through Park transformation, it is converted into the current i d and i q in the synchronous rotating coordinate system. The voltage signal U abc is similarly first transformed through Clark transformation to obtain U α and U β .

[0122] (3) Rotor position and speed estimation: The second-order super-twisting sliding mode observer (STSMO) uses the transformed voltage U α , U β and the current i d , i q signals to estimate the rotor position and speed of the motor. Among them, the rotor position and speed will be used for subsequent coordinate transformation and control calculation, and the mechanical angular velocity ω m of the motor is obtained through the pole pair P n conversion

[0123] (4) Disturbance observation: The sliding mode disturbance observer is based on the current i q , mechanical angular velocity ωm the signal to estimate the disturbance existing in the system to compensate for the uncertain factors in the system.

[0124] (5) Rotor speed outer loop control: The given rotor speed reference value N ref is subtracted from the estimated mechanical angular velocity ω m and the difference is input into the adaptive sliding mode controller (SMC). The adaptive sliding mode controller combines the disturbance estimated by the sliding mode disturbance observer to output the reference value of the quadrature-axis current where the reference value of the direct-axis current is set to 0 to achieve the maximum torque current ratio control of the permanent magnet synchronous motor.

[0125] (6) Quadrature-axis current reference value and direct-axis current reference value are respectively subtracted from the actual quadrature-axis current i q and direct-axis current i d and the differences pass through a proportional-integral (PI) controller to respectively output the voltages U d and U q .

[0126] (7) Inverse Park transformation and space vector pulse width modulation (SVPWM): The voltages U d and U q are converted into the voltages U α and U β in the two-phase stationary coordinate system through inverse Park transformation and then input into the space vector pulse width modulation module (SVPWM) to generate the control signals for driving the three-phase inverter.

[0127] (8) Motor drive: The three-phase inverter converts the DC voltage U DC into appropriate three-phase AC voltages according to the control signals output by the SVPWM module to drive the permanent magnet synchronous motor to operate and complete the entire control loop.

[0128] Embodiment 2

[0129] As Figure 3 shown, the present invention provides a sensorless permanent magnet synchronous motor control system based on a second-order STO, which is used to implement the sensorless permanent magnet synchronous motor control method based on a second-order STO in the above Embodiment 1, and specifically includes:

[0130] A stator current dynamic equation construction module 100 for constructing the stator current dynamic equation of the permanent magnet synchronous motor in the α-β stationary coordinate system;

[0131] The second-order super-twisting sliding mode observer design module 200 is used to design a second-order super-twisting sliding mode observer based on the stator current dynamic equation, dynamically estimate the back electromotive force through the current error, and extract the rotor position and speed based on the back electromotive force.

[0132] The total disturbance compensation term generation module 300 is used to fuse the back electromotive force dynamic error of the second-order super-twisting sliding mode observer and the load disturbance estimation value of the sliding mode disturbance observer to generate a total disturbance compensation term.

[0133] The speed outer-loop controller design module 400 is used to design a speed outer-loop controller by using a non-singular fast terminal sliding mode surface and an adaptive variable speed reaching law, and generate a control signal in combination with the total disturbance compensation term.

[0134] The motor drive module 500 is used to transmit the control signal to the inverter to drive the permanent magnet synchronous motor to operate.

[0135] A sensorless permanent magnet synchronous motor control system based on a second-order STO according to this embodiment is used to implement the foregoing sensorless permanent magnet synchronous motor control method based on a second-order STO. Therefore, the specific implementation manners in the sensorless permanent magnet synchronous motor control system based on a second-order STO can be seen in the embodiment part of the foregoing sensorless permanent magnet synchronous motor control method based on a second-order STO. For example, the stator current dynamic equation construction module 100, the second-order super-twisting sliding mode observer design module 200, the total disturbance compensation term generation module 300, the speed outer-loop controller design module 400, and the motor drive module 500 are respectively used to implement steps S1, S2, S3, S4, and S5 in the foregoing sensorless permanent magnet synchronous motor control method based on a second-order STO. Therefore, the specific implementation manners thereof can be referred to the descriptions of the corresponding respective part embodiments. To avoid redundancy, they will not be elaborated herein.

[0136] Embodiment III

[0137] An embodiment of the present invention provides an electronic device, which includes a processor, a memory, and a bus system. The processor and the memory are connected through the bus system. The memory is used to store instructions, and the processor is used to execute the instructions stored in the memory to implement the foregoing sensorless permanent magnet synchronous motor control method based on a second-order STO.

[0138] Embodiment IV

[0139] An embodiment of the present invention provides a computer storage medium, which stores a computer software product. The computer software product includes several instructions for causing a computer device to execute the foregoing sensorless permanent magnet synchronous motor control method based on a second-order STO.

[0140] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0141] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks or the combination of blocks.

[0142] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing devices to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device that implements the functions specified in Figure 1 one or more of the flows Figure 1 or blocks or the combination of blocks. These computer program instructions can also be loaded onto a computer or other programmable data processing devices, such that a series of operation steps are executed on the computer or other programmable devices to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable devices provide steps for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks or the combination of blocks.

[0143] Obviously, the above embodiments are only examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A sensorless permanent magnet synchronous motor control method based on second-order STO, characterized in that, Including: Construct the dynamic equation of the stator current of the permanent magnet synchronous motor in the α-β stationary coordinate system; Design a second-order super-twisting sliding mode observer based on the stator current dynamic equation, dynamically estimate the back electromotive force through the current error, and extract the rotor position and speed based on the back electromotive force; Fuse the dynamic error of the back electromotive force of the second-order super-twisting sliding mode observer and the load disturbance estimation value of the sliding mode disturbance observer to generate a total disturbance compensation term; Design a speed outer loop controller using a non-singular fast terminal sliding mode surface and an adaptive variable speed reaching law, and generate a control signal in combination with the total disturbance compensation term; Transmit the control signal to the inverter to drive the permanent magnet synchronous motor to operate.

2. The sensorless permanent magnet synchronous motor control method based on second-order STO according to claim 1, characterized in that, The mathematical model of the second-order super-twisting sliding mode observer is: In the formula, respectively represent the first-order derivatives of the estimated values of the α-axis and β-axis components of the stator current in the α-β stationary coordinate system; i α , i β respectively represent the α-axis and β-axis components of the stator current in the α-β stationary coordinate system; L represents the inductance of the stator winding of the permanent magnet synchronous motor; R s represents the resistance of the stator winding of the permanent magnet synchronous motor; u α , u β respectively represent the α-axis and β-axis components of the stator voltage in the α-β stationary coordinate system; λ1, λ2 > 0 are the gains of the second-order super-twisting sliding mode observer; e i represents the current error, that is, the difference between the actual current i α,β and the estimated current ; sign(·) is the sign function; z1 is an intermediate variable in the second-order super-twisting sliding mode observer, and its first-order derivative is determined by λ2sign(e i ).

3. The sensorless permanent magnet synchronous motor control method based on second-order STO according to claim 1, wherein The generation of the total disturbance compensation term includes: Estimation of load disturbance by sliding mode disturbance observer Extracting the dynamic error of back electromotive force through a second-order superhelical observer The total disturbance compensation term is 4. The sensorless permanent magnet synchronous motor control method based on second-order STO according to claim 1, wherein The adaptive variable speed reaching law is: wherein is the first derivative of the sliding mode surface s with respect to time, reflecting the change rate of the sliding mode surface state over time; k, ε, c, a, and b are all gains to be designed; sat(s) is the saturation function.

5. The sensorless permanent magnet synchronous motor control method based on second-order STO according to claim 4, wherein The expression of the saturation function is: where Δ e is the boundary layer thickness.

6. The sensorless permanent magnet synchronous motor control method based on second-order STO according to claim 1, characterized in that The expression of the speed outer loop controller is: Wherein, u represents the control signal output by the outer speed loop controller; s is the sliding mode surface, and k, ε, c, a, b, and g are all gains to be designed; sat(s) is the saturation function; x1 and x2 are both state variables; γ, μ, p, and q are all coefficients to be designed; is the total disturbance compensation term; k2 is the disturbance compensation gain coefficient; D is the denominator coefficient.

7. The sensorless permanent magnet synchronous motor control method based on second-order STO according to claim 1, wherein, The control function of the sliding mode disturbance observer is: where \(u\) smo is the control function of the sliding mode disturbance observer; \(s_1\) is the sliding mode surface; \(sat(s)\) is the saturation function; \(\varepsilon_1\), \(\varepsilon_2\) are coefficients to be designed; \(B\) is the viscous friction coefficient of the motor; \(J\) is the moment of inertia of the motor; \(e\) ω is the error between the actual speed and the observed speed.

8. A sensorless permanent magnet synchronous motor control system based on second-order STO, characterized in that, The system is used to implement the sensorless permanent magnet synchronous motor control method based on the second-order STO described in any one of claims 1 to 7, specifically including: A stator current dynamic equation construction module, configured to construct a dynamic equation of the stator current of the permanent magnet synchronous motor in the α-β stationary coordinate system; A second-order super-twisting sliding mode observer design module, configured to design a second-order super-twisting sliding mode observer based on the stator current dynamic equation, dynamically estimate the back electromotive force through the current error, and extract the rotor position and speed based on the back electromotive force; A total disturbance compensation term generation module, configured to fuse the dynamic error of the back electromotive force of the second-order super-twisting sliding mode observer and the load disturbance estimation value of the sliding mode disturbance observer to generate a total disturbance compensation term; A speed outer loop controller design module, configured to design a speed outer loop controller using a non-singular fast terminal sliding mode surface and an adaptive variable speed reaching law, and generate a control signal in combination with the total disturbance compensation term; An electric motor drive module, configured to transmit the control signal to the inverter to drive the permanent magnet synchronous motor to operate.

9. An electronic device, characterized in that, The electronic device includes a processor, a memory, and a bus system. The processor and the memory are connected through the bus system. The memory is used to store instructions, and the processor is used to execute the instructions stored in the memory to implement the sensorless permanent magnet synchronous motor control method based on the second-order STO described in any one of claims 1 to 7.

10. A computer storage medium, characterized in that, The computer storage medium stores a computer software product. The computer software product includes several instructions for causing a computer device to execute the sensorless permanent magnet synchronous motor control method based on the second-order STO described in any one of claims 1 to 7.

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