A novel sensorless control method for permanent magnet synchronous motor based on phase-locked loop

Abstract

This invention discloses a novel sensorless control method for a permanent magnet synchronous motor (PMSM) based on a phase-locked loop (PLL), specifically including the following steps: S1, model building; S2, designing a generalized superhelical sliding mode observer; S3, designing speed and rotor position estimation stages; S4, speed control. This invention relates to the field of motor control technology. This novel sensorless control method for a PMSM achieves high-precision sensorless control by combining a generalized superhelical sliding mode observer with a novel PLL. It utilizes the generalized superhelical sliding mode observer to suppress high-frequency chattering in the system, and combines it with the novel PLL to construct speed and position estimation stages based on the novel PLL. This reduces chattering transmission when extracting speed and other information from the arctangent estimation method, while ensuring that the closed-loop system state converges accurately and quickly to the equilibrium point, resulting in better dynamic and steady-state performance.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, specifically to a novel sensorless control method for a permanent magnet synchronous motor with a phase-locked loop. Background Technology

[0002] With the continuous advancement of science and technology, various high-tech innovations are emerging, and the concepts of energy conservation, emission reduction, and green living are increasingly valued. Permanent magnet synchronous motors (PMSMs) have been widely used due to their advantages such as simple structure, high power density, high efficiency, wide speed range, low moment of inertia, and simple maintenance. High-precision control of PMSMs requires knowledge of the rotor position. Traditionally, mechanical sensors are used to extract the rotor's speed and position information. This not only increases the motor's size and design cost but also weakens its anti-interference capability. To overcome these problems, sensorless control of PMSMs has gradually become a research hotspot.

[0003] In recent years, scholars both domestically and internationally have proposed many sensorless control methods for permanent magnet synchronous motors (PMSMs). These methods include: pulse high-frequency injection method, model reference adaptive method, extended Kalman filter method, and sliding mode sensorless speed control method. Among them, the sliding mode observer algorithm is widely used due to its simplicity, robustness, and insensitivity to system parameter changes and disturbances. However, the observation results of the sliding mode observer are easily affected by sliding mode chattering, leading to errors in the observation results and, in severe cases, system instability. Therefore, optimizing the sliding mode observer is of great significance in order to obtain better control performance and meet practical application requirements. Current improvement strategies include the extended sliding mode observer, which can directly observe the back EMF of the motor and avoid the system chattering problem caused by extracting the back EMF from the switching function. However, this method makes the observer structure extremely complex. Based on this, a novel phase-locked loop (PLL) sensorless control method for PMSMs is proposed. By combining a generalized superspiral sliding mode observer with a novel PLL, the position observation accuracy and speed control accuracy of the PMSM are greatly improved, giving the motor drive system better dynamic and steady-state performance. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a novel sensorless control method for permanent magnet synchronous motors using a phase-locked loop. This method solves the problem that the arctangent function position estimation algorithm directly introduces system chattering into the division operation, leading to the amplification of high-frequency chattering and resulting in a large angle estimation error.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention provides the following technical solution: a novel sensorless control method for a permanent magnet synchronous motor with a phase-locked loop, comprising a generalized superspiral sliding mode observer, a novel phase-locked loop module, a Park transform module, a Park inverse transform module, an SVPWM module, a Clark transform module, and a three-phase inverter, specifically including the following steps:

[0008] S1. Model building: Establish a mathematical model of a surface-mounted permanent magnet synchronous motor in the medium-to-high speed range under the stationary αβ coordinate system;

[0009] S2. Design of a generalized superspiral sliding mode observer: Constructing the sliding surface S using the observation error of the stator current. h =0, and a sliding mode observer is constructed using the generalized superspiral algorithm to obtain the generalized superspiral sliding mode observer;

[0010] S3. Design of the speed and rotor position estimation stage: Combine the novel phase-locked loop with the sliding mode observer to construct a speed and rotor position estimation stage based on the novel phase-locked loop;

[0011] S4. Speed ​​Control: After completing the design of the generalized superhelical sliding mode observer, the speed and rotor position information are obtained using the motor current and voltage components as inputs. The generalized superhelical sliding mode observer is combined with motor vector control to realize the speed control of the surface-mounted permanent magnet synchronous motor. Specifically, the output of the new phase-locked loop module... and Combined with vector control, this includes a generalized superspiral algorithm corresponding to the generalized superspiral sliding mode observer, a novel phase-locked loop module, a Park transform module, a Park inverse transform module, an SVPWM module, a Clark transform module, and a three-phase inverter. The four inputs of the generalized superspiral sliding mode observer are: the stator current αβ-axis components i output from the Clark transform module. α and i β The stator voltage αβ axis component u output by the Park inverse transform module α and u β ;

[0012] Output rotor position angle of the new phase-locked loop module These are used as inputs to the Park transform module and the inverse Park transform module, respectively, and the output is an estimated rotational speed. With a given rotational speed ω ref The difference is passed through a PI proportional-integral converter in the speed loop to obtain the q-axis current component; the stator current αβ-axis component i output by the Clark transform module. α and i β After passing through the Park transformation module, the transformed current dq-axis components i are obtained. d and i q Then, respectively with the given dq-axis current components id_ref and i q_ref The difference is then passed through a PI proportional-integral converter in the current loop before being input into the Park inverse transformer module. The stator voltage αβ axis components u output by the Park inverse transformer module are... α and u β Input to the SVPWM module, output of the SVPWM module and bus voltage u dc As the input of a three-phase inverter, the output of the three-phase inverter is used to control a permanent magnet synchronous motor (PMSM).

[0013] The present invention is further configured such that, in step S1, the mathematical model of the surface-mounted permanent magnet synchronous motor in the two-phase stationary αβ coordinate system is as follows:

[0014]

[0015] in:

[0016] In the formula: L s These are the stator inductances, ω e Let u be the electric angular velocity. α u β For stator constant voltage, i α i β For stator current, e α e β For the back electromotive force, ψ f For permanent magnet flux linkage, R s For the stator resistance, θ e This is the rotor position angle.

[0017] The present invention is further configured such that: the current estimation equation for the generalized superhelical sliding mode observer constructed in step S2 is:

[0018]

[0019] In the formula: i represents the α and β axes of the two-phase stationary coordinate system, respectively. α i β e α e β Observations for e α e β The derivative, These represent the estimation errors for the αβ axis components of the stator current. k 11 k 12 k 13 k 21 k 22 k 23 This is the sliding mode gain coefficient;

[0020] Construct the sliding surface as S h =0:

[0021] When the system state reaches the sliding surface and begins sliding motion, it will satisfy the following conditions: Right now:

[0022]

[0023] Substituting the above equation into the current error equation of the generalized super-helical sliding mode observer, we can obtain an estimate of the back electromotive force of the motor.

[0024] The present invention is further configured such that the speed and rotor position estimation step based on the novel phase-locked loop in step S3 is specifically as follows:

[0025] When the error between the actual rotor position angle and the estimated position angle is small, that is... If it tends towards zero, then set up The back potential estimation error Δe can be obtained as:

[0026]

[0027] (III) Beneficial Effects

[0028] This invention provides a novel sensorless control method for a permanent magnet synchronous motor using a phase-locked loop. It offers the following advantages:

[0029] This invention achieves high-precision sensorless control of permanent magnet synchronous motors by combining a generalized superhelical sliding mode observer with a novel phase-locked loop (PLL). The generalized superhelical sliding mode observer effectively suppresses high-frequency chattering in the system. Combined with the novel PLL, a speed and position estimation stage based on the novel PLL is constructed, reducing chattering transmission when extracting speed and other information from the arctangent estimation method. At the same time, the permanent magnet synchronous motor control system of this invention ensures that the closed-loop system state can converge to the equilibrium point accurately and quickly, exhibiting better dynamic and steady-state performance. Attached Figure Description

[0030] Figure 1 This is a block diagram illustrating the implementation of the novel phase-locked loop of the present invention;

[0031] Figure 2 This is a block diagram illustrating the principle of the generalized superhelical sliding mode observer of the present invention combined with a novel phase-locked loop;

[0032] Figure 3 This is a control block diagram of the present invention, which combines permanent magnet synchronous motor vector control with a generalized super-helical sliding mode observer and a novel phase-locked loop. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0034] Please see Figure 1-3 This invention provides a technical solution: a novel sensorless control method for a permanent magnet synchronous motor with a phase-locked loop, specifically including the following steps:

[0035] S1. Establish a mathematical model of a permanent magnet synchronous motor in the medium-to-high speed range under a stationary αβ coordinate system;

[0036] For a surface-mounted permanent magnet synchronous motor, its mathematical model in the two-phase stationary αβ coordinate system is as follows:

[0037]

[0038] in:

[0039] In the formula: L s These are the stator inductances, ω e Let u be the electric angular velocity. α u β For stator constant voltage, i α i β For stator current, e α e β For the back electromotive force, ψ f For permanent magnet flux linkage, R s For the stator resistance, θ e This is the rotor position angle.

[0040] S2. Design a generalized superhelical sliding mode observer;

[0041] A generalized superhelical sliding mode observer is designed based on the mathematical model of a permanent magnet synchronous motor. The specific design process is described in detail below.

[0042] The current equation is derived from the mathematical model of the permanent magnet synchronous motor in the medium-to-high speed range under the stationary αβ coordinate system:

[0043]

[0044] The traditional sliding mode observer is designed as follows:

[0045]

[0046] in:

[0047] Subtracting equations (1) and (2), we obtain the error equation for the stator current:

[0048]

[0049] Construct the sliding surface as S h =0:

[0050]

[0051] When the system state reaches the sliding surface and begins sliding motion, it will satisfy the following conditions: Right now:

[0052]

[0053] Substituting equation (6) into equation (4), we get:

[0054]

[0055] As shown in equation (7), the observed back electromotive force contains high-frequency chattering signals. To reduce system chattering, a generalized superhelical algorithm is adopted, which can be expressed as follows:

[0056]

[0057] Where k1, k2, and k3 are all coefficients, w is the defined auxiliary sliding surface, and sign(s) is the sign function of s;

[0058] The current estimation equation for a generalized superhelical sliding mode observer constructed using a generalized superhelical structure is as follows:

[0059]

[0060] When the observer's state variable reaches the sliding surface Then, the electromotive force can be observed. and

[0061] S3, Design of a new type of phase-locked loop;

[0062] For a surface-mounted permanent magnet synchronous motor, its back electromotive force in the two-phase stationary αβ coordinate system is as follows:

[0063]

[0064] When the error between the actual rotor position angle and the estimated position angle is small, that is... If it tends towards zero, then set up The back potential difference Δe can be obtained as:

[0065]

[0066] By using a PI proportional-integral controller, ΔE can be adjusted to approach zero, i.e. The rotor position angle is obtained by estimating the rotor angle to approximate the actual rotor position angle.

[0067] As attached Figure 3 As shown, the output of the new phase-locked loop module and Combined with vector control, this includes a generalized superspiral algorithm corresponding to the generalized superspiral sliding mode observer, a novel phase-locked loop module, a Park transform module, a Park inverse transform module, an SVPWM module, a Clark transform module, and a three-phase inverter. The four inputs of the generalized superspiral sliding mode observer are: the stator current αβ-axis components i output from the Clark transform module. α and i β The stator voltage αβ axis component u output by the Park inverse transform module α and u β ;

[0068] Output rotor position angle of the new phase-locked loop module These are used as inputs to the Park transform module and the inverse Park transform module, respectively, and the output is an estimated rotational speed. With a given rotational speed ω ref The difference is passed through a PI proportional-integral converter in the speed loop to obtain the q-axis current component; the stator current αβ-axis component i output by the Clark transform module. α and i β After passing through the Park transformation module, the transformed current dq-axis components i are obtained. d and i q Then, respectively with the given dq-axis current components i d_ref and i q_ref The difference is then passed through a PI proportional-integral converter in the current loop before being input into the Park inverse transformer module. The stator voltage αβ axis components u output by the Park inverse transformer module are... α and u β Input to the SVPWM module, output of the SVPWM module and bus voltage u dc As the input of a three-phase inverter, the output of the three-phase inverter is used to control a permanent magnet synchronous motor (PMSM).

[0069] In summary, the novel phase-locked loop permanent magnet synchronous motor (PMSM) control method based on an improved sliding mode observer proposed in this invention achieves sensorless control of the PMSM by combining a generalized super-helical sliding mode observer with a novel phase-locked loop. Furthermore, the generalized super-helical sliding mode observer designed in this invention significantly improves chatter reduction compared to traditional sliding mode observers, exhibits better robustness, and demonstrates excellent dynamic and steady-state performance.

Claims

1. A novel method of sensorless control of permanent magnet synchronous motor with phase locked loop, characterized in that: The system includes a generalized superspiral sliding mode observer, a novel phase-locked loop module, a Park converter module, a Park inverse converter module, an SVPWM module, a Clark converter module, and a three-phase inverter, specifically comprising the following steps: S1, model building: establish static Mathematical model of surface-mounted permanent magnet synchronous motor in high-speed region under stationary coordinate system S2. Design of a generalized superspiral sliding mode observer: Constructing the sliding surface using the observation error of the stator current. A sliding mode observer is constructed using the generalized superhelical algorithm, resulting in the generalized superhelical sliding mode observer. S3. Design of the speed and rotor position estimation stage: Combine the novel phase-locked loop with the sliding mode observer to construct a speed and rotor position estimation stage based on the novel phase-locked loop; S4. Speed ​​control: After completing the design of the generalized super-helical sliding mode observer, the speed and rotor position information are obtained by using the motor current and voltage components as inputs. The generalized super-helical sliding mode observer is combined with the motor vector control to realize the speed control of the surface-mounted permanent magnet synchronous motor. The current estimation equation for the generalized superspiral sliding mode observer constructed in step S2 is as follows: ； In the formula: , , , Two-phase stationary coordinate systems shaft , , , Observations , , , for , , , The derivative of , These are the stator currents. Shaft component estimation error , , , , , , , This is the sliding mode gain coefficient; Constructing the sliding surface as : ; When the system state reaches the sliding surface and begins sliding motion, it will satisfy the following conditions: ,Right now: ； The speed and rotor position estimation step based on the novel phase-locked loop in step S3 is as follows: when If it approaches zero, then ,set up The back electromotive force estimation error can be obtained. for: 。 2. The novel sensorless control method for a permanent magnet synchronous motor with a phase-locked loop according to claim 1, characterized in that: In step S1, for a surface-mounted permanent magnet synchronous motor, when both phases are stationary... The mathematical model in the coordinate system is as follows: ； in: ; In the formula: These are the stator inductors, Electric angular velocity, , For stator constant pressure, , For stator current, , It is the back electromotive force. It is a permanent magnet flux linkage. For stator resistance, This is the rotor position angle.

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