Sliding mode control method for suspension soft landing of bearingless magnetic suspension motor pump

Abstract

The invention relates to a motor control technology, and discloses a sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump, which comprises the following steps: acquiring a motion trail equation of a rotor center of suspension landing of the bearingless magnetic suspension motor pump, and selecting a motion trail sliding mode surface and a motion trail sliding mode function of the rotor center; when the center of the rotor is located on the sliding mode surface of the motion trail, the equivalent control quantity of suspension landing of the center of the rotor is calculated; when the center of the rotor is not located on the sliding mode surface of the motion trail, the correction control quantity of suspension landing of the center of the rotor is calculated; and correcting the motion trail equation according to the equivalent control quantity and the correction control quantity to obtain a corrected motion trail equation, and controlling the rotor center of the bearingless magnetic suspension motor pump to safely and softly land according to the corrected motion trail equation. The invention further provides a sliding mode control device and equipment for suspension soft landing of the bearingless magnetic suspension motor pump and a medium. According to the invention, the stability of sliding mode control of suspension soft landing of the bearingless magnetic suspension motor pump can be improved.

Description

Technical Field

[0001] The present invention relates to the field of motor control technology, and in particular to a sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump. Background Art

[0002] The bearingless magnetic levitation motor pump is a motor pump that replaces the traditional mechanical bearing with a magnetic levitation solution, so that the pump impeller is suspended in a contactless sealed shell and driven by the magnetic field of the motor. Because there is no bearing to carry the rotor, the suspension performance of the bearingless magnetic levitation motor pump is crucial in product production and use. The suspension performance includes three processes: starting suspension, suspension rotation, and stopping suspension landing. Most bearingless magnetic levitation motor pumps do not have rotor dampers or landing dampers. If the motor stops the suspension landing process without control, once the suspension motor is powered off, the rotor will inevitably be subjected to a magnetic pull in a certain direction. When the magnetic pull pulls the rotor to a certain direction, it will accelerate and hit the stator, and inevitably rub against the stator. For example, when using a bearingless magnetic levitation motor pump to transport liquid media, a slight collision between the stator and the rotor is likely to produce friction particles and contaminate the transported medium, while a serious collision between the stator and the rotor is likely to cause the failure of the internal material of the rotor magnetic steel, resulting in a decrease in motor performance and affecting the flow and head of the transported medium. Therefore, there is an urgent need for a sliding mode control method for the soft landing of a bearingless magnetic levitation motor pump, so as to improve the stability of the bearingless magnetic levitation motor pump during the suspension landing process. Summary of the invention

[0003] The invention provides a sliding mode control method for suspension soft landing of a bearingless magnetic levitation motor pump, which can improve the stability of the sliding mode control of suspension soft landing of a bearingless magnetic levitation motor pump.

[0004] To achieve the above object, the present invention provides a sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump, comprising:

[0005] Obtaining a motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump that is suspended and landed, selecting a motion trajectory sliding mode surface of the rotor center according to the motion trajectory equation, and determining a motion trajectory sliding mode function according to the motion trajectory sliding mode surface;

[0006] According to the motion trajectory sliding surface, it is judged whether the center of the rotor of the bearingless magnetic levitation motor pump is on the motion trajectory sliding surface, and when the center of the rotor of the bearingless magnetic levitation motor pump is on the motion trajectory sliding surface, an equivalent control amount of the rotor center suspension landing is calculated;

[0007] When the center of the rotor of the bearingless magnetic suspension motor pump is not on the sliding surface of the motion trajectory, a correction control amount of the rotor center suspension is calculated;

[0008] The motion trajectory equation is corrected according to the equivalent control amount and the correction control amount to obtain a corrected motion trajectory equation, and the rotor center of the bearingless magnetic levitation motor pump is controlled to land softly and safely according to the corrected motion trajectory equation.

[0009] Optionally, the step of obtaining the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump that is suspended and landed includes:

[0010] Obtaining the coordinate position of the rotor center and the deflection angle of the rotor;

[0011] The motion trajectory equations of multiple landing trajectory curves are determined according to the coordinate position and the deflection angle.

[0012] Optionally, after obtaining the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump in suspension, the method further includes specifying the kinematic equation of the rotor center according to the motion trajectory equation.

[0013] Optionally, the kinematic equation of the rotor center is specified according to the motion trajectory equation, comprising:

[0014] Calculate the motion velocity component and angular velocity component of the rotor center according to the magnetic levitation force model;

[0015] The kinematic equation is obtained by adding a correction function to the motion velocity component and the angular velocity component.

[0016] Optionally, judging whether the center of the suspended rotor of the bearingless magnetic levitation motor pump is on the motion trajectory sliding surface according to the motion trajectory sliding surface includes:

[0017] Get the target control point that the rotor center needs to reach at the current moment;

[0018] Calculate a deviation vector based on the target control point and the actual control point of the rotor center at the current moment;

[0019] It is determined according to the deviation vector whether the center of the suspended rotor of the bearingless magnetic levitation motor pump is on the sliding surface of the motion trajectory.

[0020] Optionally, when the center of the rotor of the bearingless magnetic levitation motor pump is not on the sliding surface of the motion trajectory, calculating the correction control amount of the rotor center levitation landing includes:

[0021] Obtain the system stability function and calculate the stability component according to the preset stability conditions;

[0022] The correction control amount is calculated based on the stabilizing component and the equivalent control amount of the rotor center suspension landing.

[0023] Optionally, the calculating of the correction control amount according to the stabilizing component and the equivalent control amount of the rotor center suspension landing comprises:

[0024] The correction control amount is calculated using the following formula:

[0025]

[0026] Where T is the sampling period, a is the first constant, b is the second constant, a, b>0, s x (k) is the first component of the sliding mode function, s y (k) is the second component of the sliding mode function, sgn(·) is the sign function, θ(k) is the angular velocity component at the kth discrete time point, ω eq (k) is the equivalent control quantity of the angular velocity component at the kth discrete time point, v eq is the velocity component equivalent control quantity, ω eq is the equivalent control quantity of the angular velocity component, v cr is the velocity component correction control quantity, ω cr is the angular velocity component correction control amount.

[0027] In order to solve the above problems, the present invention also provides a sliding mode control device for suspension soft landing of a bearingless magnetic suspension motor pump, the device comprising:

[0028] A motion trajectory equation acquisition module is used to obtain the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump, select the motion trajectory sliding mode surface of the rotor center according to the motion trajectory equation, and determine the motion trajectory sliding mode function according to the motion trajectory sliding mode surface;

[0029] A control amount calculation module is used to determine whether the center of the rotor of the bearingless magnetic levitation motor pump that is suspended and landed is on the motion trajectory sliding surface according to the motion trajectory sliding surface, and when the center of the rotor of the bearingless magnetic levitation motor pump that is suspended and landed is on the motion trajectory sliding surface, calculate the equivalent control amount of the rotor center suspension and landing; when the center of the rotor of the bearingless magnetic levitation motor pump that is suspended and landed is not on the motion trajectory sliding surface, calculate the correction control amount of the rotor center suspension and landing;

[0030] The landing trajectory correction module is used to correct the motion trajectory equation according to the equivalent control amount and the correction control amount to obtain a corrected motion trajectory equation, and control the rotor center of the bearingless magnetic levitation motor pump to land safely and softly according to the corrected motion trajectory equation.

[0031] In order to solve the above problem, the present invention further provides an electronic device, the electronic device comprising:

[0032] at least one processor; and,

[0033] a memory communicatively connected to the at least one processor; wherein,

[0034] The memory stores a computer program that can be executed by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the sliding mode control method for bearingless magnetic levitation motor pump suspension soft landing described above.

[0035] In order to solve the above problems, the present invention also provides a computer-readable storage medium, in which at least one computer program is stored. The at least one computer program is executed by a processor in an electronic device to implement the above-mentioned sliding mode control method for bearingless magnetic levitation motor pump suspension soft landing.

[0036] The present invention obtains the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump during suspension and landing. By determining the motion trajectory equation of the rotor center, the motion of the rotor can be controlled more accurately, thereby improving the stability and reliability of the pump. In addition, the motion trajectory equation can be corrected by calculating the equivalent control amount and the correction control amount, so that when the motor stops, the rotor can land according to a preset landing motion trajectory with a large fault tolerance rate, and further can achieve soft landing of the rotor suspension, avoiding collision and rubbing of the stator and rotor during the landing process, solving the rubbing and collision problems of the magnetic levitation motor pump during soft landing, making the performance of the magnetic levitation motor pump more reliable, and improving the stability of the bearingless magnetic levitation motor pump during the suspension and landing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic flow chart of a sliding mode control method for soft landing of a bearingless magnetic levitation motor pump provided in one embodiment of the present invention;

[0038] Figure 2 A schematic diagram of rotor suspension landing of a sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump provided by an embodiment of the present invention;

[0039] Figure 3 A schematic diagram of a trajectory of a rotor suspension landing in a sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump provided by an embodiment of the present invention;

[0040] Figure 4 A sliding mode control principle diagram of a bearingless magnetic levitation motor pump for suspension landing, which is a sliding mode control method for suspension soft landing of a bearingless magnetic levitation motor pump provided by an embodiment of the present invention;

[0041] Figure 5 A functional module diagram of a sliding mode control device for soft landing of a bearingless magnetic levitation motor pump provided by an embodiment of the present invention;

[0042] Figure 6 A schematic structural diagram of an electronic device for implementing a sliding mode control method for soft landing of a bearingless magnetic levitation motor pump provided in an embodiment of the present invention.

[0043] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0044] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0045] The embodiment of the present application provides a sliding mode control method for the soft landing of a bearingless magnetic levitation motor pump. The execution subject of the sliding mode control method for the soft landing of a bearingless magnetic levitation motor pump includes but is not limited to at least one of the electronic devices such as a server and a terminal that can be configured to execute the method provided in the embodiment of the present application. In other words, the sliding mode control method for the soft landing of a bearingless magnetic levitation motor pump can be executed by software or hardware installed on a terminal device or a server device, and the software can be a blockchain platform. The server includes but is not limited to: a single server, a server cluster, a cloud server or a cloud server cluster, etc. The server can be an independent server, or it can be a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, content delivery networks (Content Delivery Network, CDN), and big data and artificial intelligence platforms.

[0046] Reference Figure 1 FIG. 1 is a flow chart of a sliding mode control method for a bearingless magnetic levitation motor pump suspension soft landing provided by an embodiment of the present invention. In this embodiment, the sliding mode control method for a bearingless magnetic levitation motor pump suspension soft landing includes:

[0047] S1. Obtain the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump, select the motion trajectory sliding mode surface of the rotor center according to the motion trajectory equation, and determine the motion trajectory sliding mode function according to the motion trajectory sliding mode surface.

[0048] In the embodiment of the present invention, the bearingless magnetic levitation motor pump refers to a motor pump that replaces the traditional mechanical bearings with a magnetic levitation solution so that the pump impeller is suspended in a contactless sealed shell and is driven by the magnetic field of the motor.

[0049] In the embodiment of the present invention, the motion trajectory equation refers to a trajectory equation that describes the change of the position of an object in space over time, usually using time as a parameter to give the specific position coordinates of the object at different time points.

[0050] In the embodiment of the present invention, the motion trajectory sliding surface refers to a state definition equation in which the rotor center moves according to a predetermined sliding mode when the motion state of the rotor center is in a certain system state.

[0051] In the embodiment of the present invention, the motion trajectory sliding mode function refers to a function used to describe the relationship between the motion state and the sliding surface, and is composed of one or more state variable functions.

[0052] In the embodiment of the present invention, the motion trajectory equation is as follows:

[0053]

[0054] Among them, (x(t), y(t)) represents the coordinate position of the rotor center, θ(t) represents the direction angle of the rotor, and z(t) represents the coordinate position of the rotor center in the Z direction. is the coordinate change component of x(t), is the coordinate change component of x(t), is the coordinate change component of z(t).

[0055] In the embodiment of the present invention, the motion trajectory sliding mode function is confirmed by the following steps:

[0056] According to the sliding surface of the motion trajectory Based on the relationship between the motion trajectory sliding mode surface and the motion trajectory sliding mode function, the motion trajectory sliding mode function is obtained as follows: s(k)=e T (k)+λe T (k-1), where e T (k) is the transposed matrix of e(k), λ represents the velocity approaching the sliding surface, and k is the discrete time point.

[0057] As an embodiment of the present invention, the method of obtaining the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump levitating and landing includes:

[0058] Obtaining the coordinate position of the rotor center and the deflection angle of the rotor;

[0059] The motion trajectory equations of multiple landing trajectory curves are determined according to the coordinate position and the deflection angle.

[0060] Furthermore, after obtaining the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump in suspension, it also includes specifying the kinematic equation of the rotor center according to the motion trajectory equation.

[0061] Specifically, the kinematic equation of the rotor center is specified according to the motion trajectory equation, including:

[0062] Calculate the motion velocity component and angular velocity component of the rotor center according to the magnetic levitation force model;

[0063] The kinematic equation is obtained by adding a correction function to the motion velocity component and the angular velocity component.

[0064] In the embodiment of the present invention, the kinematic equation refers to a function that describes the relationship between the change of the object's velocity, acceleration and other motion state quantities over time.

[0065] In the embodiment of the present invention, the magnetic levitation force model refers to the interaction between the magnetic field and the suspended object in the magnetic levitation system, and a model of how to generate sufficient force through the magnetic field to overcome gravity and suspend the object.

[0066] Exemplarily, the calculation of the motion velocity component and the angular velocity component of the rotor center according to the magnetic levitation force model adopts the following steps:

[0067] Step 1: According to the magnetic levitation force model expression

[0068]

[0069] Where μ0 is the vacuum magnetic permeability; N m is the number of turns of the driving winding; N b is the number of turns of the suspension winding; r is the outer radius of the permanent magnet rotor; l is the axial length of the permanent magnet rotor; δ0 is the single-sided air gap between the stator and rotor; i md is the direct axis current of the driving winding; i mq is the quadrature axis current of the driving winding; u bd is the direct axis current of the suspension winding; i bq is the quadrature axis current of the suspension winding; k r is the radial magnetic tensile stiffness; I f is the equivalent excitation current of the permanent magnet; that is, the AC and DC axis current of the suspension winding Driving winding AC and DC axis current

[0070] Step 2: According to the electromagnetic torque equation of the magnetic levitation motor

[0071]

[0072] Among them, p nm Number of rotor pole pairs, L d , L q The direct-axis and quadrature-axis inductances of the drive winding, ψ f Rotor permanent magnet flux.

[0073] Step 3: According to the mechanical motion equation of the magnetic levitation motor

[0074]

[0075] Where J is the moment of inertia of the magnetic suspension motor rotor and load, T L is the load torque.

[0076]

[0077] Where m is the mass of the rotor and load.

[0078] The embodiment of the present invention obtains the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump during soft landing. By determining the motion trajectory equation of the rotor center, the movement of the rotor can be controlled more accurately, thereby improving the stability and reliability of the pump.

[0079] S2. Determine whether the center of the rotor of the bearingless magnetic levitation motor pump that is suspended and landed is on the motion trajectory sliding surface based on the motion trajectory sliding surface. When the center of the rotor of the bearingless magnetic levitation motor pump that is suspended and landed is on the motion trajectory sliding surface, calculate the equivalent control quantity of the rotor center suspension and landing.

[0080] As an embodiment of the present invention, judging whether the center of the rotor of the bearingless magnetic levitation motor pump that is suspended and landed is on the motion trajectory sliding surface according to the motion trajectory sliding surface includes:

[0081] Get the target control point that the rotor center needs to reach at the current moment;

[0082] Calculate a deviation vector based on the target control point and the actual control point of the rotor center at the current moment;

[0083] It is determined according to the deviation vector whether the center of the suspended rotor of the bearingless magnetic levitation motor pump is on the sliding surface of the motion trajectory.

[0084] In the embodiment of the present invention, the target control point refers to the target position that the rotor center needs to reach at a certain moment.

[0085] Exemplarily, the calculation of the deviation vector according to the target control point and the actual control point of the rotor center at the current moment may adopt the following steps:

[0086] Step 1: In the trajectory motion control of the rotor center position, the target control point to be reached is set as the last virtual target control point tracked at each moment;

[0087] Step 2: Define the virtual target control point that needs to be tracked at the next moment of the rotor center as (x * (t),y * (t)), the current coordinates of the rotor center are (x(t), y(t)), then the deviation vector between the rotor center and the target point is e(k) = (x(t) - x *(t),y(t)-y * (t)).

[0088] In the embodiment of the present invention, during the rotor suspension landing, if s(k)=0 can be maintained (i.e., the center of the rotor is on the sliding surface of the motion trajectory and does not deviate from the preset landing trajectory), the rotor suspension landing can softly land according to the preset trajectory.

[0089] As an embodiment of the present invention, when the center of the rotor of the bearingless magnetic levitation motor pump is on the sliding surface of the motion trajectory, the equivalent control amount of the rotor center levitation landing is calculated, and the following steps can be adopted:

[0090] According to the condition that the rotor center is on the sliding surface of the motion trajectory s(k) = 0, the equivalent control quantity u eq The following formula can be obtained during the design phase:

[0091] s(k+1)-s(k)=0

[0092] Right now

[0093] e T (k+1)+(λ-1)e T (k)-λe T (k-1)=0

[0094] According to the discretization model of the motion trajectory of the rotor center, we have:

[0095]

[0096] Where vector O = {O x ,O y}And there are

[0097]

[0098] Among them, Δf(x(k), y(k)) and Δg(x(k), y(k)) are estimated by the following formula

[0099]

[0100] Wherein, Δf(x(k), y(k)) is the first compensation function, and Δg(x(k), y(k)) is the second compensation function.

[0101] Then the equivalent control quantity can be calculated as:

[0102]

[0103] Where T is the sampling period, O x is the x component of vector O, O y is the y component of vector O, veq (k) is the equivalent control quantity of the velocity component at the kth discrete time point, ω eq (k) is the equivalent control quantity of the angular velocity component at the kth discrete time point.

[0104] S3. When the center of the rotor of the bearingless magnetic levitation motor pump is not on the sliding surface of the motion trajectory, a correction control amount of the rotor center floating and landing is calculated.

[0105] As an embodiment of the present invention, when the center of the rotor of the bearingless magnetic levitation motor pump is not on the sliding surface of the motion trajectory, the correction control amount of the rotor center levitation landing is calculated, including:

[0106] Obtain the system stability function and calculate the stability component according to the preset stability conditions;

[0107] The correction control amount is calculated based on the stabilizing component and the equivalent control amount of the rotor center suspension landing.

[0108] In the embodiment of the present invention, the system stability function refers to a function used to analyze the stability of a dynamic system, and a Lyapunov function may be used.

[0109] In the embodiment of the present invention, the Lyapunov function is as follows:

[0110] V(k)=s T (k+1)s(k+1)

[0111] In the embodiment of the present invention, the preset stability condition means that when selecting the correction control amount, the negative definiteness of the difference needs to be ensured, that is, ΔV(k)<0.

[0112] Further, the calculation of the correction control amount according to the stabilizing component and the equivalent control amount of the rotor center suspension landing includes:

[0113] The correction control amount is calculated using the following formula:

[0114]

[0115] Where T is the sampling period, a is the first constant, b is the second constant, a, b>0, s x (k) is the first component of the sliding mode function, s y (k) is the second component of the sliding mode function, sgn(·) is the sign function, θ(k) is the angular velocity component at the kth discrete time point, ω eq (k) is the equivalent control quantity of the angular velocity component at the kth discrete time point, v eq is the velocity component equivalent control quantity, ω eq is the equivalent control quantity of the angular velocity component, vcr is the velocity component correction control quantity, ω cr is the angular velocity component correction control amount.

[0116] Exemplarily, the steps of calculating the correction control amount of the rotor center suspension landing are as follows:

[0117] Choose the Lyapunov function as

[0118] V(k)=s T (k+1)s(k+1)

[0119] The difference is:

[0120] ΔV(k)=s T (k+1)s(k+1)-s T (k)s(k)

[0121] It is necessary to satisfy ΔV(k)<0 to ensure the stability of the closed-loop system. Therefore, when selecting the corrective control quantity, it is necessary to ensure the negative definiteness of the difference. From the formula ΔV(k)=s T (k+1)s(k+1)-s T (k)s(k) is negatively definite, so we can infer

[0122]

[0123] where a, b>0, sgn(·) is the sign function, s x (k) is the first component of the sliding mode function, s y (k) is the second component of the sliding mode function, and has the following relationship:

[0124]

[0125] Then the corrected control quantity can be obtained as

[0126]

[0127] After obtaining the equivalent control amount and the corrected control amount, the total control amount is:

[0128]

[0129] The embodiment of the present invention calculates the rotor suspension landing speed and the rotor angular velocity through the equivalent control amount and the correction control amount, so as to correct the compensation function after the system is discretized.

[0130] S4. Correcting the motion trajectory equation according to the equivalent control amount and the correction control amount to obtain a corrected motion trajectory equation, and controlling the rotor center of the bearingless magnetic levitation motor pump to softly land safely according to the corrected motion trajectory equation.

[0131] The embodiment of the present invention obtains the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump during suspension and landing. By determining the motion trajectory equation of the rotor center, the movement of the rotor can be controlled more accurately, thereby improving the stability and reliability of the pump. In addition, the motion trajectory equation can be corrected by calculating the equivalent control amount and the corrective control amount, so that when the motor stops, the rotor can land according to a preset landing motion trajectory with a large fault tolerance rate, and further can achieve soft landing of the rotor suspension, avoiding collision and rubbing of the stator and rotor during the landing process, solving the rubbing and collision problems of the magnetic levitation motor pump during soft landing, making the performance of the magnetic levitation motor pump more reliable, and improving the stability of the bearingless magnetic levitation motor pump during the suspension and landing process.

[0132] like Figure 2 As shown, it is a schematic diagram of rotor suspension landing of a sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump provided by an embodiment of the present invention, wherein 1 represents the inner diameter of the stator (inner rotor) or the outer diameter of the stator (outer rotor), 2 represents the outer diameter of the rotor (inner rotor) or the inner diameter of the rotor (outer rotor) when the rotor is centered, 3 represents the position of the rotor after suspension landing, point O represents the center position of the stator (also the center position when the rotor is centered), point A represents the center position of the rotor when the rotor is eccentric, and point B represents the center position of the rotor after the rotor lands.

[0133] like Figure 3 As shown, it is a schematic diagram of the trajectory of the rotor suspension landing of a sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump provided by an embodiment of the present invention. Point A represents the position of the rotor center when the rotor is eccentric, and point B represents the center position of the rotor after the rotor lands. l1, l2, l3, l4, l5 represent the trajectory from a certain suspension position point A of the rotor to the landing position point B, where the trajectories l1, l2, l3, l4, l5 are curves, actively controlling the landing trajectory of the rotor center, and the mathematical expression of the trajectory can satisfy y(t) = ax(t) 2 +bx(t)+c, where a(θ,t)>0, means that the trajectory curve opens toward the positive direction of y, such as curves l4 and l5; when a(θ,t)=0, it means that the trajectory curve is a straight line, such as curve l3, and a(θ,t)<0, it means that the trajectory curve opens toward the negative direction of y, such as curves l1 and l2.

[0134] like Figure 4 As shown, a sliding mode control principle diagram of a bearingless magnetic levitation motor pump suspension landing, which is a sliding mode control method for suspension soft landing of a bearingless magnetic levitation motor pump provided by an embodiment of the present invention, includes two outer loops and two inner loops, one outer loop is a suspension displacement loop, and the other outer loop is a rotor angle position loop; one inner loop is a suspension current loop, and the other inner loop is a drive current loop.

[0135] The rotor displacement (x(t), y(t)) is obtained from the rotor displacement sensor (such as eddy current sensor, inductance sensor, Hall sensor and photoelectric sensor) of the permanent magnet magnetic suspension motor (it can also be an asynchronous motor and a synchronous reluctance motor). The non-inductive algorithm (the displacement is analyzed by the change of inductance) is used, and then the rotor displacement is sent to the comparator for comparison with the target displacement. Finally, the interpolation of the displacement is sent to the sliding mode trajectory controller, and the motor suspension winding DC axis current command I is obtained by calculation. * Bdq, the measured phase current of the suspension winding is transformed into the suspension AC-D axis current IBdq through Park coordinate transformation (three-phase current is converted into synchronous coordinate current), and then the suspension AC-D axis current IBdq is compared with the suspension winding AC-D axis current command I * Bdq is compared, and the difference is sent to the suspension current controller, wherein the drive current controller includes but is not limited to a PID controller, a sliding mode controller, a hysteresis current controller and a proportional resonance controller. After the suspension current measurement is compared with the calculated suspension current command, the two-phase current of the suspension winding in the stationary coordinate system is calculated by the suspension current controller, and finally the phase voltage drive signal of the suspension winding is analyzed by voltage space vector modulation SVPWM, and then the power device is driven to supply power to the suspension winding of the motor.

[0136] The rotor angle position is obtained from the rotor angle sensor (e.g., Hall sensor and magnetic encoder, etc.) of the permanent magnet magnetic suspension motor (it can also be an asynchronous motor and a synchronous reluctance motor), and the measured rotor angle value (θ1, θ2, or more) is sent to the comparator for comparison with the target angle value θ*, and then the angle difference is sent to the trajectory sliding mode controller, and the trajectory sliding mode controller is used to parse the motor drive winding quadrature and direct axis current command I * Mdq, the measured phase current of the drive winding is transformed into the suspended AC-DC axis current IMdq through the Park coordinate, and then the drive AC-DC axis current IMdq is compared with the drive winding AC-DC axis current command I * Mdq, and send the comparison difference to the drive current controller, wherein the drive current controller includes but is not limited to a PID controller, a sliding mode controller, a hysteresis current controller and a proportional resonance controller. After the measured drive current is compared with the calculated drive current command, the drive current controller calculates the two-phase current of the drive winding in the stationary coordinate system, and finally resolves the phase voltage drive signal of the drive winding through voltage space vector modulation SVPWM, and then drives the power device to supply power to the drive winding of the motor.

[0137] The voltage space vector modulation SVPWM and current Park coordinate transformation of the two current inner loops both use the rotor angle position.

[0138] like Figure 5, which is a functional module diagram of a sliding mode control device for soft landing of a bearingless magnetic levitation motor pump provided by an embodiment of the present invention.

[0139] The sliding mode control device 100 for soft landing of a bearingless magnetic levitation motor pump can be installed in an electronic device. According to the functions to be implemented, the sliding mode control device 100 for soft landing of a bearingless magnetic levitation motor pump can include a motion trajectory equation acquisition module 101, a control amount calculation module 102, and a landing trajectory correction module 103.

[0140] The module described in the present invention may also be referred to as a unit, which refers to a series of computer program segments that can be executed by a processor of an electronic device and can complete fixed functions, and is stored in a memory of the electronic device.

[0141] In this embodiment, the functions of each module / unit are as follows:

[0142] The motion trajectory equation acquisition module 101 is used to obtain the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump, select the motion trajectory sliding surface of the rotor center according to the motion trajectory equation, and determine the motion trajectory sliding function according to the motion trajectory sliding surface.

[0143] In the embodiment of the present invention, the bearingless magnetic levitation motor pump refers to a motor pump that replaces the traditional mechanical bearings with a magnetic levitation solution so that the pump impeller is suspended in a contactless sealed shell and is driven by the magnetic field of the motor.

[0144] In the embodiment of the present invention, the motion trajectory equation refers to a trajectory equation that describes the change of the position of an object in space over time, usually using time as a parameter to give the specific position coordinates of the object at different time points.

[0145] In the embodiment of the present invention, the motion trajectory sliding surface refers to a state definition equation in which the rotor center moves according to a predetermined sliding mode when the motion state of the rotor center is in a certain system state.

[0146] In the embodiment of the present invention, the motion trajectory sliding mode function refers to a function used to describe the relationship between the motion state and the sliding surface, and is composed of one or more state variable functions.

[0147] In the embodiment of the present invention, the motion trajectory equation is as follows:

[0148]

[0149] Among them, (x(t), y(t)) represents the coordinate position of the rotor center, θ(t) represents the direction angle of the rotor, and z(t) represents the coordinate position of the rotor center in the Z direction. is the coordinate change component of x(t), is the coordinate change component of x(t), is the coordinate change component of z(t).

[0150] In the embodiment of the present invention, the motion trajectory sliding mode function is confirmed by the following steps:

[0151] According to the sliding surface of the motion trajectory Based on the relationship between the motion trajectory sliding mode surface and the motion trajectory sliding mode function, the motion trajectory sliding mode function is obtained as follows: s(k)=e T (k)+λe T (k-1), where e T (k) is the transposed matrix of e(k), λ represents the velocity approaching the sliding surface, and k is the discrete time point.

[0152] As an embodiment of the present invention, the method of obtaining the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump levitating and landing includes:

[0153] Obtaining the coordinate position of the rotor center and the deflection angle of the rotor;

[0154] The motion trajectory equations of multiple landing trajectory curves are determined according to the coordinate position and the deflection angle.

[0155] Furthermore, after obtaining the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump in suspension, it also includes specifying the kinematic equation of the rotor center according to the motion trajectory equation.

[0156] Specifically, the kinematic equation of the rotor center is specified according to the motion trajectory equation, including:

[0157] Calculate the motion velocity component and angular velocity component of the rotor center according to the magnetic levitation force model;

[0158] The kinematic equation is obtained by adding a correction function to the motion velocity component and the angular velocity component.

[0159] In the embodiment of the present invention, the kinematic equation refers to a function that describes the relationship between the change of the object's velocity, acceleration and other motion state quantities over time.

[0160] In the embodiment of the present invention, the magnetic levitation force model refers to the interaction between the magnetic field and the suspended object in the magnetic levitation system, and a model of how to generate sufficient force through the magnetic field to overcome gravity and suspend the object.

[0161] Exemplarily, the calculation of the motion velocity component and the angular velocity component of the rotor center according to the magnetic levitation force model adopts the following steps:

[0162] Step 1: According to the magnetic levitation force model expression

[0163]

[0164] Where μ0 is the vacuum magnetic permeability; N m is the number of turns of the driving winding; N b is the number of turns of the suspension winding; r is the outer radius of the permanent magnet rotor; l is the axial length of the permanent magnet rotor; δ0 is the single-sided air gap between the stator and rotor; i md is the direct axis current of the driving winding; i mq is the quadrature axis current of the driving winding; i bd is the direct axis current of the suspension winding; i bq is the quadrature axis current of the suspension winding; k r is the radial magnetic tensile stiffness; I f is the equivalent excitation current of the permanent magnet; that is, the AC and DC axis current of the suspension winding Driving winding AC and DC axis current

[0165] Step 2: According to the electromagnetic torque equation of the magnetic levitation motor

[0166]

[0167] Among them, p nm Number of rotor pole pairs, L d , L q The direct-axis and quadrature-axis inductances of the drive winding, ψ f Rotor permanent magnet flux.

[0168] Step 3: According to the mechanical motion equation of the magnetic levitation motor

[0169]

[0170] Where J is the moment of inertia of the magnetic suspension motor rotor and load, T L is the load torque.

[0171]

[0172] Where m is the mass of the rotor and load.

[0173] The embodiment of the present invention obtains the motion trajectory equation of the center of the suspended rotor of the bearingless magnetic levitation motor pump. By determining the motion trajectory equation of the center of the rotor, the movement of the rotor can be controlled more accurately, thereby improving the stability and reliability of the pump.

[0174] The control quantity calculation module 102 is used to determine whether the rotor center of the bearingless magnetic levitation motor pump is on the motion trajectory sliding surface according to the motion trajectory sliding surface. When the rotor center of the bearingless magnetic levitation motor pump is on the motion trajectory sliding surface, the equivalent control quantity of the rotor center suspension and landing is calculated; when the rotor center of the bearingless magnetic levitation motor pump is not on the motion trajectory sliding surface, the correction control quantity of the rotor center suspension and landing is calculated.

[0175] As an embodiment of the present invention, judging whether the center of the rotor of the bearingless magnetic levitation motor pump that is suspended and landed is on the motion trajectory sliding surface according to the motion trajectory sliding surface includes:

[0176] Get the target control point that the rotor center needs to reach at the current moment;

[0177] Calculate a deviation vector based on the target control point and the actual control point of the rotor center at the current moment;

[0178] It is determined according to the deviation vector whether the center of the suspended rotor of the bearingless magnetic levitation motor pump is on the sliding surface of the motion trajectory.

[0179] In the embodiment of the present invention, the target control point refers to the target position that the rotor center needs to reach at a certain moment.

[0180] Exemplarily, the calculation of the deviation vector according to the target control point and the actual control point of the rotor center at the current moment may adopt the following steps:

[0181] Step 1: In the trajectory motion control of the rotor center position, the target control point to be reached is set as the last virtual target control point tracked at each moment;

[0182] Step 2: Define the virtual target control point that needs to be tracked at the next moment of the rotor center as (x * (t),y * (t)), the current coordinates of the rotor center are (x(t), y(t)), then the deviation vector between the rotor center and the target point is e(k) = (x(t) - x * (t),y(t)-y * (t)).

[0183] In the embodiment of the present invention, during the rotor suspension landing, if s(k)=0 can be maintained (i.e., the center of the rotor is on the sliding surface of the motion trajectory and does not deviate from the preset landing trajectory), the rotor suspension landing can softly land according to the preset trajectory.

[0184] As an embodiment of the present invention, when the center of the rotor of the bearingless magnetic levitation motor pump is on the sliding surface of the motion trajectory, the equivalent control amount of the rotor center levitation landing is calculated, and the following steps can be adopted:

[0185] According to the condition that the rotor center is on the sliding surface of the motion trajectory s(k) = 0, the equivalent control quantity u eq The following formula can be obtained during the design phase:

[0186] s(k+1)-s(k)=0

[0187] Right now

[0188] e T (k+1)+(λ-1)e T (k)-λe T (k-1)=0

[0189] According to the discretization model of the motion trajectory of the rotor center, we have:

[0190]

[0191] Where vector O = {O x ,O y}And there are

[0192]

[0193] Among them, Δf(x(k), y(k)) and Δg(x(k), y(k)) are estimated by the following formula

[0194]

[0195] Wherein, Δf(x(k), y(k)) is the first compensation function, and Δg(x(k), y(k)) is the second compensation function.

[0196] Then the equivalent control quantity can be calculated as:

[0197]

[0198] Where T is the sampling period, O x is the x component of vector O, O y is the y component of vector O, v eq (k) is the equivalent control quantity of the velocity component at the kth discrete time point, ω eq (k) is the equivalent control quantity of the angular velocity component at the kth discrete time point.

[0199] S3. When the center of the rotor of the bearingless magnetic levitation motor pump is not on the sliding surface of the motion trajectory, a correction control amount of the rotor center floating and landing is calculated.

[0200] As an embodiment of the present invention, when the center of the rotor of the bearingless magnetic levitation motor pump is not on the sliding surface of the motion trajectory, the correction control amount of the rotor center levitation landing is calculated, including:

[0201] Obtain the system stability function and calculate the stability component according to the preset stability conditions;

[0202] The correction control amount is calculated based on the stabilizing component and the equivalent control amount of the rotor center suspension landing.

[0203] In the embodiment of the present invention, the system stability function refers to a function used to analyze the stability of a dynamic system, and a Lyapunov function may be used.

[0204] In the embodiment of the present invention, the Lyapunov function is as follows:

[0205] V(k)=s T (k+1)s(k+1)

[0206] In the embodiment of the present invention, the preset stability condition means that when selecting the correction control amount, the negative definiteness of the difference needs to be ensured, that is, ΔV(k)<0.

[0207] Further, the calculation of the correction control amount according to the stabilizing component and the equivalent control amount of the rotor center suspension landing includes:

[0208] The correction control amount is calculated using the following formula:

[0209]

[0210] Where T is the sampling period, a is the first constant, b is the second constant, a, b>0, s x (k) is the first component of the sliding mode function, s y (k) is the second component of the sliding mode function, sgn(·) is the sign function, θ(k) is the angular velocity component at the kth discrete time point, ω eq (k) is the equivalent control quantity of the angular velocity component at the kth discrete time point, v eq is the velocity component equivalent control quantity, ω eq is the equivalent control quantity of the angular velocity component, v cr is the velocity component correction control quantity, ω cr is the angular velocity component correction control amount.

[0211] Exemplarily, the steps of calculating the correction control amount of the rotor center suspension landing are as follows:

[0212] Choose the Lyapunov function as

[0213] V(k)=s T (k+1)s(k+1)

[0214] The difference is:

[0215] ΔV(k)=s T (k+1)s(k+1)-s T (k)s(k)

[0216] It is necessary to satisfy ΔV(k)<0 to ensure the stability of the closed-loop system. Therefore, when selecting the corrective control quantity, it is necessary to ensure the negative definiteness of the difference. From the formula ΔV(k)=s T (k+1)s(k+1)-s T (k)s(k) is negatively definite, so we can infer

[0217]

[0218] where a, b>0, sgn(·) is the sign function, s x (k) is the first component of the sliding mode function, s y (k) is the second component of the sliding mode function, and has the following relationship:

[0219]

[0220] Then the corrected control quantity can be obtained as

[0221]

[0222] After obtaining the equivalent control amount and the corrected control amount, the total control amount is:

[0223]

[0224] The embodiment of the present invention calculates the rotor suspension landing speed and the rotor angular velocity through the equivalent control amount and the correction control amount, so as to correct the compensation function after the system is discretized.

[0225] The landing trajectory correction module 103 is used to correct the motion trajectory equation according to the equivalent control amount and the correction control amount to obtain a corrected motion trajectory equation, and control the rotor center of the bearingless magnetic levitation motor pump to land safely and softly according to the corrected motion trajectory equation.

[0226] like Figure 6 , which is a schematic diagram of the structure of an electronic device for implementing a sliding mode control method for soft landing of a bearingless magnetic levitation motor pump provided by an embodiment of the present invention.

[0227] The electronic device may include a processor 10, a memory 11, a communication bus 12 and a communication interface 13, and may also include a computer program stored in the memory 11 and executable on the processor 10, such as a sliding mode control method program for bearingless magnetic levitation motor pump suspension soft landing.

[0228] In some embodiments, the processor 10 may be composed of an integrated circuit, for example, a single packaged integrated circuit, or a plurality of packaged integrated circuits with the same or different functions, including one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and combinations of various control chips. The processor 10 is the control core (ControlUnit) of the electronic device, and uses various interfaces and lines to connect various components of the entire electronic device, and executes or executes programs or modules stored in the memory 11 (for example, executing a sliding mode control method program for soft landing of a bearingless magnetic levitation motor pump, etc.), and calls data stored in the memory 11 to execute various functions of the electronic device and process data.

[0229] The memory 11 includes at least one type of readable storage medium, and the readable storage medium includes flash memory, mobile hard disk, multimedia card, card-type memory (for example: SD or DX memory, etc.), magnetic memory, disk, optical disk, etc. In some embodiments, the memory 11 can be an internal storage unit of an electronic device, such as a mobile hard disk of the electronic device. In other embodiments, the memory 11 can also be an external storage device of an electronic device, such as a plug-in mobile hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device. Further, the memory 11 can also include both an internal storage unit of the electronic device and an external storage device. The memory 11 can not only be used to store application software and various types of data installed in the electronic device, such as the code of a sliding mode control method program for soft landing of a bearingless magnetic levitation motor pump, etc., but can also be used to temporarily store data that has been output or is to be output.

[0230] The communication bus 12 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. The bus is configured to realize connection and communication between the memory 11 and at least one processor 10, etc.

[0231] The communication interface 13 is used for communication between the above-mentioned electronic device and other devices, including a network interface and a user interface. Optionally, the network interface may include a wired interface and / or a wireless interface (such as a WI-FI interface, a Bluetooth interface, etc.), which is generally used to establish a communication connection between the electronic device and other electronic devices. The user interface may be a display (Display), an input unit (such as a keyboard (Keyboard)), and optionally, the user interface may also be a standard wired interface, a wireless interface. Optionally, in some embodiments, the display may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, and an OLED (Organic Light-Emitting Diode, organic light-emitting diode) touch device, etc. Among them, the display may also be appropriately referred to as a display screen or a display unit, which is used to display information processed in the electronic device and to display a visual user interface.

[0232] Figure 6 Only an electronic device with components is shown, and those skilled in the art will understand that Figure 6 The structure shown does not constitute a limitation on the electronic device, and may include fewer or more components than shown in the figure, or combine certain components, or arrange the components differently.

[0233] For example, although not shown, the electronic device may also include a power source (such as a battery) for supplying power to each component. Preferably, the power source may be logically connected to the at least one processor 10 through a power management device, so that the power management device can realize functions such as charging management, discharging management, and power consumption management. The power source may also include one or more DC or AC power sources, recharging devices, power failure detection circuits, power converters or inverters, power status indicators, and other arbitrary components. The electronic device may also include a variety of sensors, Bluetooth modules, Wi-Fi modules, etc., which will not be repeated here.

[0234] It should be understood that the embodiment is for illustration only and the scope of the patent application is not limited to this structure.

[0235] The sliding mode control method program for bearingless magnetic suspension motor pump suspension soft landing stored in the memory 11 of the electronic device is a combination of multiple instructions. When running in the processor 10, it can achieve:

[0236] Obtaining a motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump that is suspended and landed, selecting a motion trajectory sliding mode surface of the rotor center according to the motion trajectory equation, and determining a motion trajectory sliding mode function according to the motion trajectory sliding mode surface;

[0237] According to the motion trajectory sliding surface, it is judged whether the center of the rotor of the bearingless magnetic levitation motor pump is on the motion trajectory sliding surface, and when the center of the rotor of the bearingless magnetic levitation motor pump is on the motion trajectory sliding surface, an equivalent control amount of the rotor center suspension landing is calculated;

[0238] When the center of the rotor of the bearingless magnetic suspension motor pump is not on the sliding surface of the motion trajectory, a correction control amount of the rotor center suspension is calculated;

[0239] The motion trajectory equation is corrected according to the equivalent control amount and the correction control amount to obtain a corrected motion trajectory equation, and the rotor center of the bearingless magnetic levitation motor pump is controlled to land softly and safely according to the corrected motion trajectory equation.

[0240] Specifically, the specific implementation method of the processor 10 for the above instructions can refer to the description of the relevant steps in the corresponding embodiment of the accompanying drawings, which will not be repeated here.

[0241] Furthermore, if the module / unit integrated in the electronic device 1 is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. The computer-readable storage medium can be volatile or non-volatile. For example, the computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, and a read-only memory (ROM).

[0242] The present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor of an electronic device, the computer program can implement:

[0243] Obtaining a motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump that is suspended and landed, selecting a motion trajectory sliding mode surface of the rotor center according to the motion trajectory equation, and determining a motion trajectory sliding mode function according to the motion trajectory sliding mode surface;

[0244] According to the motion trajectory sliding surface, it is judged whether the center of the rotor of the bearingless magnetic levitation motor pump is on the motion trajectory sliding surface, and when the center of the rotor of the bearingless magnetic levitation motor pump is on the motion trajectory sliding surface, an equivalent control amount of the rotor center suspension landing is calculated;

[0245] When the center of the rotor of the bearingless magnetic suspension motor pump is not on the sliding surface of the motion trajectory, a correction control amount of the rotor center suspension is calculated;

[0246] The motion trajectory equation is corrected according to the equivalent control amount and the correction control amount to obtain a corrected motion trajectory equation, and the rotor center of the bearingless magnetic levitation motor pump is controlled to land softly and safely according to the corrected motion trajectory equation.

[0247] In the several embodiments provided by the present invention, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the modules is only a logical function division, and there may be other division methods in actual implementation.

[0248] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0249] In addition, each functional module in each embodiment of the present invention may be integrated into one processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional modules.

[0250] It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0251] Therefore, no matter from which point of view, the embodiments should be regarded as illustrative and non-restrictive, and the scope of the present invention is limited by the appended claims rather than the above description, so it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any attached figure mark in the claims should not be regarded as limiting the claims involved.

[0252] The blockchain referred to in this invention is a new application mode of computer technologies such as distributed data storage, peer-to-peer transmission, consensus mechanism, encryption algorithm, etc. Blockchain is essentially a decentralized database, a string of data blocks generated by cryptographic methods. Each data block contains a batch of network transaction information, which is used to verify the validity of its information (anti-counterfeiting) and generate the next block. Blockchain can include the underlying blockchain platform, platform product service layer, and application service layer.

[0253] The embodiments of the present application can acquire and process relevant data based on artificial intelligence technology. Among them, artificial intelligence (AI) is the theory, method, technology and application system that uses digital computers or machines controlled by digital computers to simulate, extend and expand human intelligence, perceive the environment, acquire knowledge and use knowledge to obtain the best results.

[0254] In addition, it is clear that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices stated in the system claim can also be implemented by one unit or device through software or hardware. The words first, second, etc. are used to indicate names, and do not indicate any particular order.

[0255] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump, characterized in that: The method comprises: Obtaining a motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump that is suspended and landed, selecting a motion trajectory sliding mode surface of the rotor center according to the motion trajectory equation, and determining a motion trajectory sliding mode function according to the motion trajectory sliding mode surface; According to the motion trajectory sliding surface, it is judged whether the center of the rotor of the bearingless magnetic levitation motor pump is on the motion trajectory sliding surface, and when the center of the rotor of the bearingless magnetic levitation motor pump is on the motion trajectory sliding surface, an equivalent control amount of the rotor center suspension landing is calculated; When the center of the rotor of the bearingless magnetic suspension motor pump is not on the sliding surface of the motion trajectory, a correction control amount of the rotor center suspension is calculated; The motion trajectory equation is corrected according to the equivalent control amount and the correction control amount to obtain a corrected motion trajectory equation, and the rotor center of the bearingless magnetic levitation motor pump is controlled to land softly and safely according to the corrected motion trajectory equation.

2. The sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump according to claim 1, characterized in that: The method of obtaining the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump levitating and landing includes: Obtaining the coordinate position of the rotor center and the deflection angle of the rotor; The motion trajectory equations of multiple landing trajectory curves are determined according to the coordinate position and the deflection angle.

3. The sliding mode control method for suspension soft landing of a bearingless magnetic levitation motor pump according to claim 1 or 2, characterized in that: After obtaining the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump, the method further includes specifying the kinematic equation of the rotor center according to the motion trajectory equation.

4. The sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump as claimed in claim 3, characterized in that: The kinematic equation of the rotor center is specified according to the motion trajectory equation, including: Calculate the motion velocity component and angular velocity component of the rotor center according to the magnetic levitation force model; The kinematic equation is obtained by adding a correction function to the motion velocity component and the angular velocity component.

5. The sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump according to claim 1, characterized in that: The step of judging whether the center of the rotor of the bearingless magnetic suspension motor pump that is suspended and landed is on the motion trajectory sliding surface according to the motion trajectory sliding surface includes: Get the target control point that the rotor center needs to reach at the current moment; Calculate a deviation vector based on the target control point and the actual control point of the rotor center at the current moment; It is determined according to the deviation vector whether the center of the suspended rotor of the bearingless magnetic levitation motor pump is on the sliding surface of the motion trajectory.

6. The sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump as claimed in claim 1, characterized in that: When the center of the rotor of the bearingless magnetic levitation motor pump is not on the sliding surface of the motion trajectory, the correction control amount of the rotor center levitation landing is calculated, including: Obtain the system stability function and calculate the stability component according to the preset stability conditions; The correction control amount is calculated based on the stabilizing component and the equivalent control amount of the rotor center suspension landing.

7. The sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump as claimed in claim 6, characterized in that: The calculating of the correction control amount according to the stabilizing component and the equivalent control amount of the rotor center suspension landing comprises: The correction control amount is calculated using the following formula: Where T is the sampling period, a is the first constant, b is the second constant, a, b>0, s x (k) is the first component of the sliding mode function, s y (k) is the second component of the sliding mode function, sgn(·) is the sign function, θ(k) is the angular velocity component at the kth discrete time point, ω eq (k) is the equivalent control quantity of the angular velocity component at the kth discrete time point, v eq is the equivalent control quantity of the velocity component, ω eq is the equivalent control quantity of the angular velocity component, v cr is the velocity component correction control quantity, ω cr is the angular velocity component correction control amount.

8. A sliding mode control device for suspension soft landing of a bearingless magnetic suspension motor pump, characterized in that: The device can implement the sliding mode control method for suspension soft landing of a bearingless magnetic suspension motor pump as claimed in any one of claims 1 to 7, and the device comprises: A motion trajectory equation acquisition module is used to obtain the motion trajectory equation of the rotor center of the bearingless magnetic levitation motor pump, select the motion trajectory sliding mode surface of the rotor center according to the motion trajectory equation, and determine the motion trajectory sliding mode function according to the motion trajectory sliding mode surface; A control amount calculation module is used to determine whether the center of the rotor of the bearingless magnetic levitation motor pump that is suspended and landed is on the motion trajectory sliding surface according to the motion trajectory sliding surface, and when the center of the rotor of the bearingless magnetic levitation motor pump that is suspended and landed is on the motion trajectory sliding surface, calculate the equivalent control amount of the rotor center suspension and landing; when the center of the rotor of the bearingless magnetic levitation motor pump that is suspended and landed is not on the motion trajectory sliding surface, calculate the correction control amount of the rotor center suspension and landing; The landing trajectory correction module is used to correct the motion trajectory equation according to the equivalent control amount and the correction control amount to obtain a corrected motion trajectory equation, and control the rotor center of the bearingless magnetic levitation motor pump to land safely and softly according to the corrected motion trajectory equation.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the sliding mode control method for soft landing of a bearingless magnetic levitation motor pump as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the sliding mode control method for suspension soft landing of a bearingless magnetic levitation motor pump as described in any one of claims 1 to 7 is implemented.

Images