Non-inductive control method used for fan driving and based on novel super-spiral sliding-mode observer

Abstract

The invention discloses a non-inductive control method used for fan driving and based on a novel super-spiral sliding-mode observer. The non-inductive control method comprises the steps that a permanent magnet synchronous motor mathematical model under a static alpha-beta coordinate system is established; determining a super-spiral sliding-mode observer for estimating the back electromotive force; adjusting the gain coefficient of the super-spiral sliding-mode observer through the self-adaptive rotating speed adjustment factor; carrying out filtering processing on the back electromotive force estimated by the super-spiral sliding mode observer; inputting the filtered counter electromotive forces of the alpha and beta axes into a phase-locked loop to obtain the rotor position and speed estimation value of the permanent magnet synchronous motor; accurate decoupling of motor stator current is achieved through vector control, and the position and the rotating speed of a rotor are estimated through a novel super-spiral sliding mode observer. According to the non-inductive control method used for fan driving and based on the novel super-spiral sliding-mode observer, a self-adaptive rotating speed regulation factor is designed, so that the gain coefficient is dynamically adjusted according to the change of the rotating speed of the motor, and the accuracy of estimating the back electromotive force is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of motor control, and in particular relates to a sensorless control method based on a novel super-helical sliding mode observer for fan driving. Background Art

[0002] Fan drive systems are widely used in modern industry, especially in HVAC (heating, ventilation and air conditioning), ventilation and various mechanical equipment. Permanent magnet synchronous motor (PMSM) has become the preferred motor for fan drive due to its high efficiency, good dynamic response characteristics and high power density. However, traditional PMSM control methods usually rely on position sensors to obtain the position information of the motor rotor to achieve precise speed and position control, but the use of position sensors will increase the complexity and cost of the system, and may be affected by environmental factors such as temperature and humidity, resulting in sensor failure or performance degradation.

[0003] In recent years, domestic and foreign scholars have proposed many control methods for permanent magnet synchronous motors without position sensors, including pulse high-frequency injection method, model reference adaptive method, extended Kalman filter method and sliding mode speed sensorless method. Among them, the sliding mode observer has been widely used due to its simple algorithm, strong robustness, and insensitivity to system parameter changes and disturbances. However, the observation results of the sliding mode observer are easily disturbed by the sliding mode chattering, which causes errors in the observation results and may cause system instability in severe cases. Therefore, in order to obtain better control effects and meet practical application needs, it is of great significance to optimize the sliding mode observer. Summary of the invention

[0004] The present invention provides a sensorless control method based on a novel super-helical sliding mode observer for fan drive to solve the above-mentioned technical problems, and specifically adopts the following technical solutions:

[0005] A sensorless control method for fan drive based on a novel super-helical sliding mode observer comprises:

[0006] S1: Based on the stator current equation of the permanent magnet synchronous motor, a mathematical model of the permanent magnet synchronous motor in the stationary αβ coordinate system is established;

[0007] S2: According to the established mathematical model of permanent magnet synchronous motor, the super-helical sliding mode observer is determined to be used for estimating back electromotive force;

[0008] S3: The gain coefficient of the super-helical sliding mode observer is adjusted by the adaptive speed adjustment factor;

[0009] S4: filtering the back electromotive force estimated by the super-helical sliding mode observer;

[0010] S5: inputting the filtered back electromotive force of the α and β axes into a phase-locked loop, and obtaining the estimated value of the rotor position and speed of the permanent magnet synchronous motor through the phase-locked loop processing;

[0011] S6: Combine the novel super-helical sliding mode observer with the motor vector control strategy to achieve accurate decoupling of the motor stator current through vector control, and use the novel super-helical sliding mode observer to estimate the rotor position and speed.

[0012] Furthermore, in step S1, the voltage equation is as follows:

[0013]

[0014] In the formula, u α and u β are the voltages of the stator α-axis and β-axis components, i α and i β is the current of the stator α-axis and β-axis components, L d and L q are the inductances of the d-axis and q-axis components, Ψ f is the permanent magnet flux of the motor rotor, e α and e β is the back electromotive force;

[0015] Its back electromotive force equation is as follows:

[0016]

[0017] Where, w e is the electrical angular velocity of the motor, θ e is the rotor electrical angle;

[0018] Rewrite the voltage equation into a current state equation:

[0019]

[0020] Furthermore, in step S2, the super-helical sliding mode control law is expressed as follows:

[0021]

[0022] Where u is the control input, u cont is a continuous control term, u int is the integral control term, s is the sliding mode variable, k p and k i is the sliding mode gain, where k p To enhance dynamic performance and suppress buffeting, k i Used to improve steady-state accuracy;

[0023] Substituting equation (4) into the current state equation (3), we obtain:

[0024]

[0025] in:

[0026]

[0027]

[0028] Furthermore, in step S3, the expression of the adaptive speed adjustment factor g is as follows:

[0029]

[0030] In the formula, K is a constant, λ is the sensitivity coefficient of the adjustment factor, λ>0, is the current motor speed, w ref is the reference speed; Substituting equation (8) into equation (6) and (7) respectively, we get:

[0031]

[0032] Furthermore, in step S4, an adaptive SOGI filter is determined based on an improved second-order generalized integrator to filter the back electromotive force estimated by the super-spiral sliding mode observer to filter out harmonics and DC bias components in the estimated back electromotive force signal.

[0033] Further, in step S4, the dynamic characteristics of the improved second-order generalized integrator are shown in the following linearized transfer function:

[0034]

[0035] In the formula, k 1 ,k 2 ,k 3 and k w is the gain coefficient, w n is the resonant frequency, and s is the Laplace operator.

[0036] Furthermore, in step S5, the closed-loop transfer function of the phase-locked loop is:

[0037]

[0038] In the formula, is the rotor angle, is the rotor angular velocity, e′ α and e′ β are the back electromotive force of the α-axis and β-axis respectively.

[0039] The benefit of the present invention lies in that the sensorless control method based on the novel super-helical sliding mode observer for fan drive is provided, and an adaptive speed adjustment factor is designed to dynamically adjust the gain coefficient according to the change of motor speed, thereby improving the accuracy of estimating back electromotive force.

[0040] The present invention is also beneficial in that it provides a sensorless control method for fan drive based on a novel super-helical sliding mode observer, which uses a cascaded improved two-generalized integrator structure to extract the back electromotive force fundamental wave, while filtering out the estimated low-order harmonics and DC bias components in the back electromotive force. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0042] Figure 1 This is a flow chart of the sensorless control method for fan drive based on a novel super-helical sliding mode observer proposed by the present invention;

[0043] Figure 2 A schematic diagram of a back electromotive force super-helical sliding mode observer applied in the present invention;

[0044] Figure 3 Schematic diagram of an improved super-helical sliding mode observer of the present invention;

[0045] Figure 4 It is a structural diagram of the improved second-order generalized integrator of the present invention;

[0046] Figure 5 It is a phase-locked loop control structure diagram of the present invention;

[0047] Figure 6 It is a schematic diagram of the novel super spiral sliding mode observer of the present invention;

[0048] Figure 7 This is a structural diagram of the novel super-helical sliding mode observer combined with the motor vector control strategy of the present invention. DETAILED DESCRIPTION

[0049] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0050] like Figure 1 The present invention shows a sensorless control method for fan drive based on a novel super-helical sliding mode observer, which specifically includes:

[0051] Step S1: Based on the permanent magnet synchronous motor stator current equation, a permanent magnet synchronous motor mathematical model in a stationary αβ coordinate system is established.

[0052] The construction basis of the traditional sliding mode observer is a two-phase stationary coordinate system, and its voltage equation is as follows:

[0053]

[0054] In the formula, u α and u β are the voltages of the stator α-axis and β-axis components, i α and i β is the current of the stator α-axis and β-axis components, L d and L q are the inductances of the d-axis and q-axis components, Ψ f is the permanent magnet flux of the motor rotor, e α and e β is the back electromotive force.

[0055] Its back electromotive force equation is as follows:

[0056]

[0057] Where, w e is the electrical angular velocity of the motor, θ e is the rotor electrical angle.

[0058] Rewrite equation (1) into the current state equation:

[0059]

[0060] Step S2: According to the established mathematical model of the permanent magnet synchronous motor, a super-helical sliding mode observer is determined to be used for estimating the back electromotive force.

[0061] Specifically, please refer to Figure 2 As shown, the super spiral sliding mode control law (STSMC) is expressed as follows:

[0062]

[0063] Where u is the control input, u cont is a continuous control term, u int is the integral control term, s is the sliding mode variable, k p and k i is the sliding mode gain, where k p To enhance dynamic performance and suppress buffeting, ki Used to improve steady-state accuracy.

[0064] Substituting equation (4) into the current state equation (3), we obtain:

[0065]

[0066] in:

[0067]

[0068] Step S3: adjusting the gain coefficient of the super-helical sliding mode observer through an adaptive speed adjustment factor.

[0069] In step S3, if Figure 3 As shown, the expression of the adaptive speed adjustment factor g is as follows:

[0070]

[0071] In the formula, K is a constant, λ is the sensitivity coefficient of the adjustment factor, λ>0, is the current motor speed, w ref is the reference speed. The design uses the error-driven nonlinear adjustment mechanism to increase the factor value when the error is large to enhance the dynamic adjustment ability and accelerate convergence; and to reduce the factor value when the error is small to reduce the gain, thereby suppressing the influence of high-frequency noise on steady-state accuracy. By adjusting the initial gain K and the sensitivity coefficient λ, the balance between dynamic performance and steady-state accuracy is achieved, and the adaptability and anti-interference ability of the observer to different speed conditions are improved. Substituting equation (8) into (6) and (7) respectively, we get:

[0072]

[0073] The super-helical sliding mode observer established in step S2 is improved through the above process.

[0074] Step S4: filtering the back electromotive force estimated by the super-helical sliding mode observer.

[0075] In an embodiment of the present application, an adaptive SOGI filter is determined based on an improved second-order generalized integrator to filter the back electromotive force estimated by the super spiral sliding mode observer to filter out harmonics and DC bias components in the estimated back electromotive force signal.

[0076] Specifically, if Figure 4 As shown, the dynamic characteristics of the improved second-order generalized integrator are shown in the following linearized transfer function:

[0077]

[0078] In the formula, k 1 ,k2 ,k 3 and k w is the gain coefficient, w n is the resonant frequency, and s is the Laplace operator.

[0079] Step S5: Input the filtered back electromotive force of the α and β axes into a phase-locked loop, and obtain the estimated value of the rotor position and speed of the permanent magnet synchronous motor through the phase-locked loop processing.

[0080] In step S5, Figure 5 As shown, the closed-loop transfer function of the phase-locked loop is:

[0081]

[0082] In the formula, is the rotor angle, is the rotor angular velocity, e′ α and e′ β are the back electromotive force of the α-axis and β-axis respectively.

[0083] Through the above process, the super spiral sliding mode observer established in step S2 is adjusted to obtain a novel super spiral sliding mode observer of the present application, such as Figure 6 shown.

[0084] Step S6: Combine the novel super-helical sliding mode observer with the motor vector control strategy, realize accurate decoupling of the motor stator current through vector control, and use the novel super-helical sliding mode observer to estimate the rotor position and speed, so as to realize efficient and stable motor speed control.

[0085] Specifically, the figure is a structural diagram of the novel super-helical sliding mode observer provided by the present invention combined with the motor vector control strategy, which further illustrates the application of the present invention in the motor vector control.

[0086] like Figure 7 As shown, this system adopts i d =0 vector control method, and estimate the rotor position and speed through the improved super-helical sliding mode observer, so as to realize position sensorless control. The output rotor position angle of the improved super-helical sliding mode observer is passed as input to the Park transform and inverse Park transform modules. First, the three-phase current is converted into the current component i in the two-phase stationary coordinate system by using Clark coordinate transformation. α and i β , and then converted into the current component i in the rotating coordinate system through Park coordinate transformation d and i q Next, the actual i d and i q The current component and the given reference current component i drefand i qref Subtract the current error, and adjust it through the PI controller in the current control loop to finally get the control voltage u d and u q After the inverse Park transformation, u in the rotation coordinate system d and u q The voltage component u converted back to the stationary coordinate system α and u β ,These voltage signals are then generated by the space vector pulse width modulation (SVPWM) unit to generate corresponding switching signals for controlling the switching state of the three-phase inverter, thereby converting the DC voltage into three-phase AC voltage to drive the motor stator winding, achieving high-precision motor drive and control.

[0087] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A sensorless control method for fan drive based on a novel super-helical sliding mode observer, characterized in that: Include: S1: Based on the stator current equation of the permanent magnet synchronous motor, a mathematical model of the permanent magnet synchronous motor in the stationary αβ coordinate system is established; S2: According to the established mathematical model of permanent magnet synchronous motor, the super-helical sliding mode observer is determined to be used for estimating back electromotive force; S3: The gain coefficient of the super-helical sliding mode observer is adjusted by the adaptive speed adjustment factor; S4: filtering the back electromotive force estimated by the super-helical sliding mode observer; S5: inputting the filtered back electromotive force of the α and β axes into a phase-locked loop, and obtaining the estimated value of the rotor position and speed of the permanent magnet synchronous motor through the phase-locked loop processing; S6: Combine the novel super-helical sliding mode observer with the motor vector control strategy to achieve accurate decoupling of the motor stator current through vector control, and use the novel super-helical sliding mode observer to estimate the rotor position and speed.

2. The sensorless control method based on a novel super-helical sliding mode observer for fan drive according to claim 1 is characterized in that: In step S1, the voltage equation is as follows: In the formula, u α and u β are the voltages of the stator α-axis and β-axis components, i α and i β is the current of the stator α-axis and β-axis components, L d and L q are the inductances of the d-axis and q-axis components, Ψ f is the permanent magnet flux of the motor rotor, e α and e β is the back electromotive force; Its back electromotive force equation is as follows: Where, w e is the electrical angular velocity of the motor, θ e is the rotor electrical angle; Rewrite the voltage equation into a current state equation:

3. The sensorless control method for fan drive based on a novel super-helical sliding mode observer according to claim 2 is characterized in that: In step S2, the super-helical sliding mode control law is expressed as follows: Where u is the control input, u cont is a continuous control term, u int is the integral control term, s is the sliding mode variable, k p and k i is the sliding mode gain, where k p To enhance dynamic performance and suppress buffeting, k i Used to improve steady-state accuracy; Substituting equation (4) into the current state equation (3), we obtain: in:

4. The sensorless control method for fan drive based on a novel super-helical sliding mode observer according to claim 3 is characterized in that: In step S3, the expression of the adaptive speed adjustment factor g is as follows: In the formula, K is a constant, λ is the sensitivity coefficient of the adjustment factor, λ>0, is the current motor speed, w ref is the reference speed; Substituting equation (8) into equation (6) and (7) respectively, we get:

5. The sensorless control method for fan drive based on a novel super-helical sliding mode observer according to claim 4 is characterized in that: In step S4, an adaptive SOGI filter is determined based on an improved second-order generalized integrator to filter the back electromotive force estimated by the super spiral sliding mode observer to filter out harmonics and DC bias components in the estimated back electromotive force signal.

6. The sensorless control method for fan drive based on a novel super-helical sliding mode observer according to claim 5 is characterized in that: In step S4, the dynamic characteristics of the improved second-order generalized integrator are shown in the following linearized transfer function: In the formula, k1, k2, k3 and k w is the gain coefficient, w n is the resonant frequency, and s is the Laplace operator.

7. The sensorless control method for fan drive based on a novel super-helical sliding mode observer according to claim 6 is characterized in that: In step S5, the closed-loop transfer function of the phase-locked loop is: In the formula, is the rotor angle, is the rotor angular velocity, e′ α and e′ β are the back electromotive force of the α-axis and β-axis respectively.

Images