Impeller control method and device

Abstract

The invention provides an impeller control method and device.The method comprises the steps that the power frequency of a motor is controlled to be first frequency within a first time period, so that an impeller moves between a first position and a second position in a reciprocating mode, and the first time period is the time when a first magnetic body and a second magnetic body have alignment parts when the impeller rotates; application of the target suspension current to the stator during a second period of time generates a first magnetic force to maintain the impeller in the first position. The impeller is controlled to reciprocate in the first time period and is stabilized at the first position in the second time period, and the thrombus formation risk can be reduced by controlling the periodic reciprocating motion of the impeller; in addition, the permanent magnet excitation magnetic pole composed of the first magnetic body and the second magnetic body provides axial force for the impeller shaft to reciprocate upwards, and compared with the mode that the movement of the impeller is controlled by controlling suspension current flowing through a stator winding, power consumption of the motor can be greatly reduced, and stable operation of the motor is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, and in particular to a method and device for controlling an impeller. BACKGROUND

[0002] Ventricular Assist Devices (VADs) are commonly used to assist the pumping action of a failing heart. More specifically, a VAD includes a housing having an inlet, an outlet, and a rotor mounted in the housing. The inlet is connected to a chamber of a patient's heart, typically the left ventricle, and the outlet is connected to an artery, such as the aorta. Rotation of the rotor drives blood from the inlet toward the outlet and thereby assists blood flow from the chamber of the heart into the artery.

[0003] Non-contact impeller suspension technology addresses the support and energy consumption issues in highly mechanical designs, such that the impeller is suspended and rotates within the housing during operation. Fluid is pumped through a gap between the face of the impeller and the inner face of the housing, and blood passing through the gap can contain particles. Changes in the flow rate and / or rotational speed of the VAD cause these particles to generate solid or semi-solid deposits in the patient, which can generate thrombi that can remain on the face of the impeller or the housing and impede their operation, which is harmful or even fatal to the patient. SUMMARY

[0004] Embodiments of the present application provide an impeller control method and device, which can prevent thrombus generation while reducing motor power consumption.

[0005] In a first aspect, embodiments of the present application provide an impeller control method, applied to a ventricular assist device, the ventricular assist device including a housing, an impeller arranged in the housing, a motor driving the impeller to rotate, n first magnetic bodies and n second magnetic bodies, the motor including a rotor and a stator, the rotor and the n first magnetic bodies being fixedly connected to the impeller, the stator driving the rotor to rotate, the n second magnetic bodies being arranged in the housing, the n first magnetic bodies rotating with the impeller and aligning with the n second magnetic bodies in the axial direction of the housing, n being an integer greater than or equal to 2; the method comprising:

[0006] controlling the power supply frequency of the motor to be a first frequency in a first time period to reciprocate the impeller between a first position and a second position, the first time period being a time when the n first magnetic bodies and the n second magnetic bodies are at least partially aligned in the axial direction of the housing when the impeller rotates;

[0007] applying a target suspension current to the stator to generate a first magnetic force to keep the impeller in the first position in a second time period, the second time period being a time when the n first magnetic bodies and the n second magnetic bodies have no alignment part in the axial direction of the casing while the impeller rotates.

[0008] In a second aspect, an embodiment of the present application provides a ventricular assist device, the ventricular assist device comprising:

[0009] a casing;

[0010] an impeller arranged in the casing;

[0011] a motor driving the impeller to rotate in suspension, the motor comprising a rotor and a stator, the stator driving the rotor to rotate in suspension;

[0012] n first magnetic bodies and n second magnetic bodies, the rotor and the n first magnetic bodies being fixed to the impeller, the n second magnetic bodies being arranged in the casing, the n first magnetic bodies being aligned with the n second magnetic bodies in the axial direction of the casing while the impeller rotates, n being an integer greater than or equal to 2;

[0013] a control unit connected to the stator, the control unit being configured to:

[0014] control a power supply frequency of the motor to be a first frequency in a first time period to move the impeller reciprocally between a first position and a second position, the first time period being a time when the n first magnetic bodies and the n second magnetic bodies are at least partially aligned in the axial direction of the casing while the impeller rotates;

[0015] applying a target suspension current to the stator to generate a first magnetic force to keep the impeller in the first position in a second time period, the second time period being a time when the n first magnetic bodies and the n second magnetic bodies have no alignment part in the axial direction of the casing while the impeller rotates.

[0016] In a third aspect, an embodiment of the present application provides a medical device, the medical device comprising a processor, a memory, a communication interface, and one or more programs, the one or more programs being stored in the memory and configured to be executed by the processor, the program comprising instructions for performing part or all of the steps described in the method of the first aspect.

[0017] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium storing a computer program for electronic data exchange, wherein the computer program causes a computer to perform part or all of the steps described in the method of the first aspect.

[0018] In a fifth aspect, a computer program product is provided, which includes a non-transitory computer readable storage medium storing a computer program. The computer program is operable to cause a computer to execute some or all of the steps of the method described in the first aspect of the embodiments of the present application. The computer program product can be a software installation package.

[0019] The technical scheme provided in the present application controls the power frequency of the motor to be the first frequency in the first time period to reciprocally move the impeller between the first position and the second position, the first time period being the time when the n first magnetic bodies and the n second magnetic bodies are at least partially aligned in the axial direction of the shell during the rotation of the impeller; and the target suspension current is applied to the stator in the second time period to generate the first magnetic force to keep the impeller at the first position, the second time period being the time when the n first magnetic bodies and the n second magnetic bodies do not have an aligned part in the axial direction of the shell during the rotation of the impeller. The present application controls the reciprocating movement of the impeller in the first time period and keeps the impeller at the first position in the second time period, so that the periodic reciprocating movement of the impeller can reduce the risk of thrombosis; and the axial force of the reciprocating movement of the impeller in the axial direction is provided by the permanent magnetic exciting magnetic poles composed of the first magnetic bodies and the second magnetic bodies, which can greatly reduce the power consumption of the motor and improve the stable operation of the motor compared with the movement of the impeller controlled by the suspension current flowing through the stator winding. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0021] Figure 1 is a structural schematic diagram of a ventricular assist device provided by the embodiments of the present application;

[0022] Figure 2 is a structural schematic diagram of a motor provided by the embodiments of the present application;

[0023] Figure 3 is a schematic diagram of force acting on an impeller provided by the embodiments of the present application;

[0024] Figure 4 is Figure 3 is an explosion schematic diagram of A in FIG. 8;

[0025] Figure 5 is a flow schematic diagram of an impeller control method provided by the embodiments of the present application;

[0026] Figure 6is a schematic diagram of positions of the first magnetic body and the second magnetic body at a t1 moment provided by an embodiment of the present application;

[0027] Figure 7 is a schematic diagram of positions of the first magnetic body and the second magnetic body at a t2 moment provided by an embodiment of the present application;

[0028] Figure 8 is a schematic diagram of positions of the first magnetic body and the second magnetic body at a t3 moment provided by an embodiment of the present application;

[0029] Figure 9 is a schematic diagram of positions of the first magnetic body and the second magnetic body at a t4 moment provided by an embodiment of the present application;

[0030] Figure 10 is a schematic diagram of positions of the first magnetic body and the second magnetic body at a t5 moment provided by an embodiment of the present application;

[0031] Figure 11 is a schematic diagram of a structure of a medical device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order for those skilled in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application are described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the description of the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0033] The terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, software, product, or device that includes a series of steps or units is not limited to the listed steps or units, but also includes steps or units not listed or other steps or units inherent to the process, method, product, or device.

[0034] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The phrase appears at various places in the specification is not necessarily all referring to the same embodiment, nor is it necessarily referring to a common or alternative embodiment. It is explicitly and implicitly understood that the embodiments described herein can be combined with each other.

[0035] "Rotational speed" in the present application refers to the rotational speed of a motor or an electric machine, which is associated with the rotational speed of a rotor or an impeller of a ventricular assist device, and can be defined as revolutions per minute.

[0036] The medical device involved in the present application can be a ventricular assist device, for example, an implantable ventricular assist device. The ventricular assist device can be used for left heart, right heart or both. The ventricular assist device can include at least one blood pump, which can be a magnetic suspension pump.

[0037] The ventricular assist device can be attached to the heart via a ventricular connection assembly (such as a top ring, a ventricular cuff, a ventricular sleeve), which can be sutured to the heart and coupled to the blood pump, and the other end of the blood pump can be connected to the ascending aorta via an outlet tube and / or an artificial blood vessel connected to the outlet tube, so that the VAD can effectively transfer blood from the weakened ventricle and push it to the aorta, thereby circulating to the remaining part of the patient's vascular system, providing ventricular assist function for the patient.

[0038] The ventricular assist system includes a ventricular assist device 100, an external controller, and a transmission assembly connecting the ventricular assist device 100 to the external controller. One end of the transmission assembly is connected to the motor inside the ventricular assist device 100, and the other end is connected to the external controller arranged outside the body through the abdominal skin of the patient. The external controller is used to realize the monitoring of the ventricular assist device 100, which can realize the functions of control and data display of the ventricular assist device 100, fault detection alarm and data recording. The transmission assembly can be a percutaneous cable, which can include one or more power supply wires and one or more communication wires; or in some embodiments, the cable only has a power supply wire, which can realize the functions of power supply and communication at the same time.

[0039] As shown in Figures 1-4 The ventricular assist device 100 includes a housing with an inlet tube and an impeller 20 for pushing fluid. The housing has a chamber 10, and the housing is also provided with a fluid inlet 14 and a fluid outlet 15 respectively communicating with the chamber 10. The impeller 20 can be suspended and rotated in the chamber 10, and the rotation of the impeller 20 can generate centrifugal force to transport fluid, so that the fluid can enter the chamber 10 from the fluid inlet 14 and be output from the fluid outlet 15. Wherein, the suspended rotation of the impeller 20 refers to that the impeller 20 does not contact the cavity wall of the chamber 10 when rotating. Specifically, the housing has opposite first and second side walls 11 and 12, and the chamber 10 is located between the first and second side walls 11 and 12. The fluid inlet 14 is provided on the second side wall 12.

[0040] As shown in Figure 1As shown, the ventricular assist device 100 further comprises a motor 30 and a position sensor 40 for driving the impeller 20 to suspend rotation. The motor 30 comprises a stator 31 and a rotor 32 arranged on both sides of the first side wall 11. The stator 31 is fixed to the outer side of the first side wall 11 relative to the chamber 10, and the corresponding rotor 32 is located in the chamber 10 and is fixedly connected with the impeller 20. The rotor 32 can be composed of a plurality of magnets arranged at equal angles along the same circle, and adjacent poles are different from each other. Specifically, the rotor 32 is a Halbach array magnet. Further, the rotor 32 is arranged in the impeller 20 and on the side of the impeller 20 close to the first side wall 11. When the impeller 20 suspends rotation in the chamber 10, there is a gap between the impeller 20 and the second side wall 12, and there is a gap between the impeller 20 and the first side wall 11. The secondary flow channels are formed between the impeller 20 and the second side wall 12 and between the impeller 20 and the first side wall 11. After the fluid flows into the impeller 20, a small part of the fluid flows out of the flow channel of the impeller 20 and does not directly flow to the fluid outlet 15, but is recombined into the main flow channel through the secondary flow channel.

[0041] For example, the motor 30 can be a three-phase brushless direct current motor (BLDC), the stator 31 has three windings controlled by different corresponding phases U, V, and W of the three-phase motor control, and the BLDC motor 30 can further comprise an inverter circuit which can be used to convert DC input into three-phase output. For example, the ventricular assist device 100 can receive an alternating current three-phase input.

[0042] The ventricular assist device 100 further comprises a control unit 33 electrically connected with the stator 31 and the position sensor 40, respectively. The control unit 33 can determine the axial position of the impeller 20 in the chamber 10 according to the received distance value, i.e., determine the distance between the impeller 20 relative to the first side wall 11 and / or the second side wall 12, and further determine the position of the impeller 20 in the chamber 10.

[0043] In Figure 1In the embodiment shown in FIG. 1, the first side wall 11 and the second side wall 12 are arranged in parallel to each other. When the impeller 20 is stably suspended and rotated in the chamber 10, the rotation axis 21 of the impeller 20 is perpendicular to the first side wall 11 and the second side wall 12 at the same time. The second side wall 12 has a first face 22, and the first side wall 11 has a second face 23 which is spaced from and opposite to the first face 22. The chamber 10 is located between the first face 22 and the second face 23, i.e. the first face 22 and the second face 23 are actually two opposite cavity walls of the chamber 10. The position sensor 40 is fixedly arranged between the stator 31 and the first side wall 11, and is used to measure the distance of the impeller 20 along the central axis of the fluid inlet 14 relative to the second face 23. The position sensor 40 transmits the measured distance value to the control unit 33.

[0044] It should be noted that when the impeller 20 is stably suspended and rotated in the chamber 10, the rotation axis 21 of the impeller 20 is aligned with the central axis of the fluid inlet 14. In the present application, the "axial direction" refers to the direction along the central axis of the fluid inlet 14, the "radial direction" refers to the direction perpendicular to the central axis of the fluid inlet 14, or the direction perpendicular to the axial direction. The axial direction of the ventricular assist device 100 and the axial direction of the housing in the present application both refer to the direction of the central axis of the fluid inlet 14.

[0045] The ventricular assist device 100 further comprises n first magnetic bodies 61 and n second magnetic bodies 62. The n first magnetic bodies 61 are located in the chamber 10 and fixedly connected to the impeller 20. The n second magnetic bodies 62 are arranged on the housing. The number of the first magnetic bodies 61 is equal to the number of the second magnetic bodies 62. The n first magnetic bodies 61 can rotate with the impeller 20 and align with the n second magnetic bodies 62 in the axial direction of the housing. That is, when the first magnetic bodies 61 and the second magnetic bodies 62 are aligned in the axial direction of the housing, each first magnetic body 61 is aligned with a second magnetic body 62 in the axial direction of the housing. When the first magnetic bodies 61 and the second magnetic bodies 62 are at least partially aligned in the axial direction of the housing, the first magnetic bodies 61 and the second magnetic bodies 62 can generate a magnetic thrust in the axial direction. Specifically, the first magnetic bodies 61 and the second magnetic bodies 62 are permanent magnets, and the magnetic poles on the opposite sides of the first magnetic bodies 61 and the second magnetic bodies 62 are the same.

[0046] The n first magnetic bodies 61 are arranged at equal intervals along the same circle, and the n second magnetic bodies 62 are arranged at equal intervals along the same circle. When the n first magnetic bodies 61 and the n second magnetic bodies 62 are at least partially aligned in the axial direction of the housing, the projection of each first magnetic body 61 in the axial direction of the housing at least partially falls on one second magnetic body 62, or the projection of each second magnetic body 62 in the axial direction of the housing at least partially falls on one first magnetic body 61, so that the magnetic thrust in the axial direction can be generated between the first magnetic body 61 and the second magnetic body 62. In other words, when the n first magnetic bodies 61 and the n second magnetic bodies 62 are at least partially aligned in the axial direction of the housing, the projection of the first magnetic body 61 in the axial direction of the housing at least partially falls on the second magnetic body 62, or the projection of the second magnetic body 62 in the axial direction of the housing at least partially falls on the first magnetic body 61. Specifically, when the first magnetic body 61 and the second magnetic body 62 are completely aligned in the axial direction of the housing, each first magnetic body 61 is completely aligned with one second magnetic body 62, the projection of each first magnetic body 61 in the axial direction of the housing completely falls on the second magnetic body 62, or the projection of each second magnetic body 62 in the axial direction of the housing completely falls on the first magnetic body 61, and the positions of the n first magnetic bodies 61 and the n second magnetic bodies 62 in the axial direction of the housing correspond one by one. When the first magnetic body 61 and the second magnetic body 62 are partially aligned in the axial direction of the housing, each first magnetic body 61 is partially aligned with one second magnetic body 62, the projection of each first magnetic body 61 in the axial direction of the housing partially falls on one second magnetic body 62, or the projection of each second magnetic body 62 in the axial direction of the housing partially falls on one first magnetic body 61.

[0047] Specifically, the projection of the n first magnetic bodies 61 on the second face 23 of the first side wall 11 and the projection of the n second magnetic bodies on the second face 23 of the first side wall 11 are concentric and arranged at equal intervals. The first magnetic body 61 and the second magnetic body 62 are both arc-shaped.

[0048] Specifically, the width of the gap between two adjacent first magnetic bodies 61 is greater than or equal to the length in the circumferential direction of each second magnetic body 62, and the width of the gap between two adjacent second magnetic bodies 62 is greater than or equal to the length in the circumferential direction of each first magnetic body 61, so that when the first magnetic body 61 and the second magnetic body 62 are not aligned in the axial direction of the shell, the projection of each second magnetic body 62 in the axial direction of the shell is located in the gap between two adjacent first magnetic bodies 61, and the projection of each first magnetic body 61 in the axial direction of the shell is located in the gap between two adjacent second magnetic bodies 62, or in other words, the projection of each second magnetic body 62 on the second face 23 of the first side wall 11 is located in the gap between the projections of two adjacent first magnetic bodies 61 on the second face 23 of the first side wall 11, and the projection of each first magnetic body 61 on the second face 23 of the first side wall 11 is located in the gap between the projections of two adjacent second magnetic bodies 62 on the second face 23 of the first side wall 11. Wherein, the circumferential length of the first magnetic body 61 and the second magnetic body 62 is equal, that is, the length of the projection of the first magnetic body 61 on the second face 23 of the first side wall 11 corresponds to the central angle of the circle, and the length of the projection of the second magnetic body 62 on the second face 23 of the first side wall 11 corresponds to the central angle of the circle. The length in the circumferential direction of the first magnetic body 61 refers to the length of the first magnetic body 61 in the circumferential direction of the impeller 20; the length in the circumferential direction of the second magnetic body 62 refers to the length of the second magnetic body 62 in the circumferential direction of the shell. Wherein, the circumferential direction of the impeller 20 is the circumferential direction around the central axis 21 of the impeller 20; the circumferential direction of the shell is the circumferential direction around the central axis of the fluid inlet 14. In this article, the length in the circumferential direction of the first magnetic body 61 and the circumferential length of the first magnetic body 61 are understood in the same way; the length in the circumferential direction of the second magnetic body 62 and the circumferential length of the first magnetic body 61 are understood in the same way.

[0049] As shown in Figure 6 n=2, the circumferential length of the first magnetic body 61 corresponds to a central angle of 45°, and the gap between the two first magnetic bodies 61 corresponds to a central angle of 180°. The circumferential length of the second magnetic body 62 corresponds to a central angle of 45°, and the gap between the two second magnetic bodies 62 corresponds to a central angle of 180°. When the line connecting the centers of the two first magnetic bodies 61 is perpendicular to the line connecting the centers of the two second magnetic bodies 62 (out-of-plane perpendicular), the projections of the two first magnetic bodies 61 on the second face 23 of the first side wall 11 and the projections of the two second magnetic bodies 62 on the second face 23 of the first side wall 11 are circumferentially equal and equally spaced, that is, the projections of the first magnetic body 61 and the second magnetic body 62 on the second face 23 divide the circle into 8 regions of equal circumferential length, each region corresponds to a central angle θ=45°.

[0050] In other embodiments, when n = 3, the circumferential length of the first magnetic body 61 corresponds to a central angle of 30°, and the gap between every two first magnetic bodies 61 corresponds to a central angle of 120°. The circumferential length of the second magnetic body 62 corresponds to a central angle of 30°, and the gap between every two second magnetic bodies 62 corresponds to a central angle of 120°. When the angle between the line connecting the centers of the first magnetic bodies 61 and the line connecting the centers of the second magnetic bodies 62 is 60°, the projections of the three first magnetic bodies 61 on the second surface 23 of the first side wall 11 and the projections of the three second magnetic bodies 62 on the second surface 23 of the first side wall 11 are concentric and equally spaced, i.e., the projections of the first magnetic bodies 61 and the second magnetic bodies 62 on the second surface 23 divide the circle into 12 regions of equal circumferential length, and each region corresponds to a central angle θ = 30°.

[0051] In other embodiments, when n = 4, the circumferential length of the first magnetic body 61 corresponds to a central angle of 22.5°, and the gap between every two first magnetic bodies 61 corresponds to a central angle of 90°. The circumferential length of the second magnetic body 62 corresponds to a central angle of 22.5°, and the gap between every two second magnetic bodies 62 corresponds to a central angle of 90°. When the angle between the line connecting the centers of the first magnetic bodies 61 and the line connecting the centers of the second magnetic bodies 62 is 45°, the projections of the four first magnetic bodies 61 on the second surface 23 of the first side wall 11 and the projections of the four second magnetic bodies 62 on the second surface 23 of the first side wall 11 are concentric and equally spaced, i.e., the projections of the first magnetic bodies 61 and the second magnetic bodies 62 on the second surface 23 divide the circle into 16 regions of equal circumferential length, and each region corresponds to a central angle θ = 22.5°. The same applies to other embodiments.

[0052] Specifically, the rotor 32 and the n first magnetic bodies 61 are arranged at intervals in the radial direction of the impeller 20. The impeller 20 is substantially annular, and the radial direction of the impeller 20 refers to the direction perpendicular to the central axis 21 of the impeller 20. More specifically, the first recess 231 and the second recess 232 are formed in the impeller 20, and the second recess 232 is arranged at an interval in the radial direction of the impeller 20 from the first recess 231. The first recess 231 is used to accommodate the rotor 32, and the second recess 232 is used to accommodate the n first magnetic bodies 61. By arranging the first recess 231 and the second recess 232 to accommodate the rotor 32 and the first magnetic body 61, respectively, both surfaces of the impeller 20 close to the first side wall 11 and close to the second side wall 12 can be planar, and the flow of fluid between the impeller 20 and the first surface 22 of the second side wall 12 and between the impeller 20 and the second surface 23 of the first side wall 11 is smoother, preventing the fluid from being blocked and forming a blockage or obstruction in the chamber 10.

[0053] Specifically, the second magnetic body 62 is arranged on the first side wall 12. In the illustrated embodiment, the second magnetic body 62 is arranged on the side of the first side wall 11 facing away from the second face 23.

[0054] The impeller 20 is axially movable. During rotation, the impeller 20 is suspended within the housing, specifically the chamber 10, by a contactless bearing, such as a magnetic bearing, which generates a magnetic levitation system. Specifically, in a direction perpendicular to the central axis of the fluid inlet 14, or in other words radially, a twisting force is generated by the attractive and repulsive forces of the stator 31 and the rotor 32, which causes the impeller 20 to rotate radially. As shown in the figure, in the axial direction, a magnetic force F1 can be generated between the stator 31 and the rotor 32, and a magnetic force F2 is generated between the stator core and the rotor 32, which together act on the impeller 20, causing the impeller 20 to be suspended in the chamber 10 at a first position L1. During rotation of the rotor 32, the first magnetic body 61 and the second magnetic body 62 have an aligned portion when the impeller 20 rotates, generating an axial magnetic force F3 that causes the impeller 20 to move within the chamber 10, for example from the first position L1 to a second position L2. Figure 3

[0055] F1 is the magnetic levitation force provided by the winding in the stator 31, and F2 is the magnetic attraction force of the rotor 32 to the stator core. The magnetic levitation force can be controlled by controlling the size and phase of the current flowing through the winding, thereby controlling the size and direction of the magnetic levitation force F1. F3 is the periodic excitation magnetic force of the first magnetic body 61 to the second magnetic body 62, where the excitation magnetic force F3 is greater than the magnetic levitation force F1.

[0056] When the motor 30 is not started or stationary, the impeller 20 will be parked at the first side wall 11 or the second side wall 12 of the housing, or at a position not in contact with the housing. When the motor 30 is started, the magnetic force F1 and the magnetic force F2 acting on the impeller 20 cause the impeller to be suspended at the first position L1, as shown in the figure. Figure 4 ​The first position L1 is a position where the impeller 20 is naturally stable or balanced during operation. The first position L1 can be at or near the center of the chamber 10, or the balanced position is another position of the chamber 10 (but at the position, the impeller 20 does not contact the housing), when the impeller 20 is at the position of the chamber 10, the magnetic levitation force Fl generated by the stator winding is substantially equal to the magnetic force F2 between the rotor 32 and the stator 31 in the axial direction. During rotation of the impeller 20, the impeller 20 is subjected to a periodic excitation magnetic force F3 under the action of the first magnetic body 61 and the second magnetic body 62, that is, the excitation magnetic force F3 is generated when the first magnetic body 61 and the second magnetic body 62 are aligned during rotation of the impeller 20, which makes the impeller 20 move in the axial direction, such as from the first position L1 to the second position L2. Wherein when the impeller 20 is subjected to the excitation magnetic force F3, the magnetic levitation force Fl is removed. Compared with controlling the movement of the impeller 20 by adjusting the current flowing through the stator 31, using the first magnetic body 61 and the second magnetic body 62 to generate the excitation magnetic force does not require additional power consumption, which can reduce the power consumption of the motor 30. Wherein the first position L1 and the second position L2 are both within the allowable safe distance between the impeller 20 and the housing.

[0057] The control unit 33 includes hardware and software for controlling various aspects of the operation of the motor 30. The control unit 33 can be coupled to the motor 30 through an interface for collecting at least one data of the motor 30. The at least one data can include a measured current flowing through the stator coil, data measured by the position sensor 40, motor speed, pressure difference across the ventricular assist device 100, flow pulsatility, fluid flow rate, etc.

[0058] The position sensor 40 can be a Hall sensor in an example; the Hall sensor can be used to measure the distance value of the impeller 20 relative to the second face 23 in the chamber 10, and can transmit the distance value to the control unit 33. In one embodiment, the position sensor 40 is electrically connected to the control unit 33 through a flexible data line, and transmits the distance value measured by the position sensor 40 to the control unit 33 through the flexible data line. Specifically, the position sensor 40 is disposed opposite to the passing path of the rotor 32 on the impeller 20. When the S pole and the N pole of the rotor 32 pass by the position sensor 40 alternately during rotation of the impeller 20, the position sensor 40 outputs a signal level representing the magnetic flux intensity in a sinusoidal manner, so that by detecting the time variation of the output signal of the position sensor 40, the positional relationship between the rotor 32 and the stator 31 can be detected, and thus the rotation speed of the current flowing through the stator 31 to drive the impeller 20 to rotate can be calculated.

[0059] In combination with the above description, the present application is described below from the perspective of method examples.

[0060] Please refer to Figure 5 ,Figure 5 A flow chart of a method for controlling an impeller is provided for embodiments of the present application, which is applied to a ventricular assist device as shown in Figures 1-4 Figure 5 The method includes the following steps.

[0061] S510, controlling the power frequency of the motor to be a first frequency in a first time period, so as to reciprocally move the impeller between a first position and a second position, the first time period being a time when the n first magnetic bodies and the n second magnetic bodies are at least partially aligned in the axial direction of the housing during rotation of the impeller.

[0062] When the ventricular assist device 100 is implanted in a desired position, at this time, the motor 30 is not started, and the impeller 20 is in a static position, which is a position where the impeller 20 is parked at the first side wall 11 or the second side wall 12, i.e., a position where the impeller 20 is in contact with the housing; or alternatively, the static position is a position not in contact with the housing. After starting the motor 30, the control unit 33 applies a suspension current to the stator winding in the axial direction according to the target rotational speed n0 set by the user, to generate a magnetic suspension force F1 in the axial direction, so as to move the impeller 20 from the static position to the first position L1, and then keep the impeller 20 in the first position L1; at the same time, a rotating current is applied to the stator winding to control the impeller 20 to rotate along the rotating axis 21 to the target rotational speed n0. In an example, the first position L1 is a position where the impeller 20 is within a range of 0.05mm-0.5mm from the first side wall 11 or the second side wall 12, i.e., the distance between the impeller 20 and the first side wall 11 or the distance between the impeller 20 and the second side wall 12 is within a range of 0.05mm-0.5mm. The target rotational speed n0 can be within a range of 2200RPM-4300RPM.

[0063] In actual application, a pulsation control function is started when the motor 30 is running, which is used to control the impeller 20 to periodically pulsate in the axial direction, i.e., the impeller 20 is periodically moved within a preset range in the axial direction, so as to periodically increase the gap between the impeller 20 and the first face 22 or the gap between the impeller 20 and the second face 23, to prevent blood from stagnating and coagulating in the secondary flow channel to form a thrombus. However, such periodic large-amplitude axial movement of the impeller 20 will cause the suspension current for controlling the suspension of the impeller 20 to sharply increase or decrease, greatly increasing power consumption and making the motor 30 unstable, and the increased power consumption will cause heating to increase the temperature in the ventricular assist device 100, thereby affecting the operating efficiency of the motor 30 and the safety of the user.

[0064] ​Based on this, the permanent magnet excitation magnetic pole composed of the first magnetic body 61 and the second magnetic body 62 is arranged in the motor 30, the periodic excitation magnetic force is provided in the operation of the impeller 20 by the passive magnetic bearing composed of the permanent magnet excitation magnetic pole, the provided excitation magnetic force with permanent periodicity enables the rotor 32 to change in the axial direction in a short time, and the symmetric variable axial force can be provided, so that the stable reciprocating movement of the impeller 20 in the axial direction can be realized; the current flowing through the stator winding is controlled to keep the impeller 20 in the first position L1, so that the impeller 20 is subjected to periodic controllable movement during operation, the adhesion of plasma protein is reduced, the risk of thrombosis is significantly reduced, and the operation life of the ventricular assist device 100 is improved. At the same time, the permanent magnet excitation magnetic pole does not need additional power consumption, and the motor power consumption can be reduced.

[0065] When the impeller 20 enters the excitation area, the excitation area is an area in which the n first magnetic bodies 61 and the n second magnetic bodies 62 are at least partially aligned in the axial direction, that is, in the first time period, the first time period is the time period during which the impeller 20 passes through the excitation area, the control unit 33 can remove the magnetic suspension force F1 applied to the impeller 20, and the magnetic thrust force F3 generated between the first magnetic body 61 and the second magnetic body 62 acts on the impeller 20, so that the impeller 20 is suspended and reciprocally moves in the axial direction. Compared with the reciprocating movement of the impeller 20 in the axial direction by continuously changing the size and phase of the suspension current applied to the stator winding, the present application only needs to apply a fixed size of suspension current to the stator winding in the second time period, so as to generate the magnetic suspension force F1 in the axial direction to keep the impeller 20 in the first position L1. Thus, it is not necessary to sharply increase or decrease and change the direction of the suspension current, which greatly reduces the power consumption of the motor.

[0066] When the impeller 20 rotates into the excitation area, the impeller 20 is subjected to a changing excitation magnetic force (magnetic thrust force F3). The impeller 20 performs a simple harmonic motion in the excitation area, F3=-Kx+b, wherein K is a magnetic force coefficient, x is the movement distance of the impeller 20, and b is a magnetic force correction coefficient. Therefore, when the impeller 20 rotates in the excitation area, the displacement of the impeller 20 in the axial direction with respect to time satisfies the displacement equation: L(t)=Acos(ωt+φ), wherein A is the amplitude (the maximum distance of the axial movement of the impeller 20), which belongs to the inherent property and is related to the volume of the first magnetic body 61 and the allowed movement distance; ω is the excitation angular frequency, (wherein K is a magnetic force coefficient, m is the mass of the impeller);φ is the initial phase (determined by the initial condition);t=1 / f, f is the power frequency (hz) of the motor. Therefore, after the ventricular assist device 100 is manufactured, that is, A, ω and φ are determined, it is known that the displacement L(t) of the impeller 20 in the axial direction is determined by the power frequency f of the motor.

[0067] When setting the moving range of the impeller 20 in the axial direction, the control unit 33 can determine the first frequency f1 according to the second position L2, and then change the power supply frequency of the motor 30 to the first frequency f1 in the first time period, so that the impeller 20 rotates at the first rotating speed n1 and moves in the axial direction from the first position L1 to the second position L2 and then from the second position L2 to the first position L1, realizing one reciprocating movement. The distance value between the second position L2 and the impeller 20 or the first face 22 and the impeller 20 is in the range of 0.05mm-0.5mm. The distance between the second position L2 and the second face 23 or the first face 22 is less than the distance between the first position L1 and the second face 23 or the first face 22, and both the first position L1 and the second position L2 are within the allowable safety distance range.

[0068] Specifically, during the rotation of the impeller 20, the alignment part between the first magnetic body 61 and the second magnetic body 62 gradually increases with the rotation of the impeller 20, and reaches the maximum when the first magnetic body 61 and the second magnetic body 62 are completely aligned. Then, with the rotation of the impeller 20, the alignment part between the first magnetic body 61 and the second magnetic body 62 gradually decreases until there is no alignment part. Therefore, with the rotation of the first magnetic body 61 in the excitation area, the excitation magnetic force F3 received by the impeller 20 first gradually increases to the maximum, and then gradually decreases from the maximum to 0, so that the impeller 20 moves from the first position L1 to the second position L2 and then from the second position F1 to the first position L1, realizing one reciprocating movement.

[0069] S520, applying a target suspension current to the stator in a second time period to generate a first magnetic force to keep the impeller at the first position, the second time period being the time when the n first magnetic bodies and the n second magnetic bodies have no alignment part in the axial direction of the shell during the rotation of the impeller.

[0070] The second time period is the time period when the impeller 20 passes through the non-excitation area, i.e. the time period when the impeller 20 passes through the non-alignment part between the first magnetic body 61 and the second magnetic body 62 in one cycle. When the impeller 20 rotates out of the excitation area, there is no alignment part between the first magnetic body 61 and the second magnetic body 62, and the magnetic thrust F3 generated between the first magnetic body 61 and the second magnetic body 62 is 0. At this time, the control unit 33 applies a target suspension current to the stator, so that the magnetic suspension force F1 generated by the stator winding acts on the impeller 20, and the magnetic suspension force F1 replaces the excitation magnetic force F3 to apply an axial force in the upward direction to the impeller 20, so that the impeller 20 is suspended in the chamber 10 and kept at the first position L1.

[0071] The magnitude of the target levitation current can be determined based on the first position L1, the magnetic forces F1 and F2 acting on the impeller 20. Throughout the cycle, the impeller 20 operates at the target speed n0. Therefore, based on the first speed n1 in the excitation region, the second speed n2 of the impeller 20 in the non-excitation region can be calculated, and the power supply frequency corresponding to the second speed is the second frequency f2. At the initial moment of the second time period, the control unit 33 changes the power supply frequency of the motor 30 to the second frequency f2 to control the impeller 20 speed to the second speed n2; simultaneously, it applies the target levitation current to the stator windings to levit the impeller 20 to the first position L1.

[0072] In this application, the impeller 20 rotates 360° / n times per excitation cycle. Within this excitation cycle, half of the region is the excitation region, and the other half is the non-excitation region. Both the first magnetic body 61 and the second magnetic body 62 are arc-shaped. The angle of the central angle corresponding to the circumferential length of the first magnetic body 61 and the second magnetic body 62 in their respective circles is related to their quantity n. Specifically, the angle of the central angle of the circumferential length of the first magnetic body 61 and the second magnetic body 62 in their respective circles is 360° / (4*n). For example, when n=2, the angle of the central angle corresponding to the circumferential length of the first magnetic body 61 is 45°, and the angle of the central angle corresponding to the circumferential length of the second magnetic body 62 is 45°. When the line connecting the centers of the two first magnetic bodies 61 is perpendicular to the line connecting the centers of the two second magnetic bodies (opposite plane perpendicularity), the projections of the two first magnetic bodies 61 onto the second surface 23 of the first sidewall 11 and the projections of the two second magnetic bodies onto the second surface 23 of the first sidewall 11 are concyclic and equally spaced. That is, the projections of the first magnetic bodies 61 and the second magnetic bodies 62 onto the second surface 23 divide the circle into eight regions of equal circumferential length, with a central angle θ = 45° corresponding to each region. The impeller 20 rotates 180° for one excitation cycle. Figures 6-10 As shown, the impeller 20 rotates through four regions in one cycle. Within this cycle, half the time is spent passing through the excitation region and the other half is spent passing through the non-excitation region. The impeller 20 moves from the first position L1 to the second position L2, then moves from the second position L2 back to the first position L1 and remains at the first position L1.

[0073] like Figure 6As shown, at time t1, the impeller 20 is at its zero-point position. At this zero-point position, the center of the first magnetic body 61 is aligned with the zero-point position line, and the second magnetic body 62 is perpendicular to this zero-point position line. The projection of the center of the first magnetic body 61 onto the second surface 23 of the first sidewall 11 along the housing axial direction is 90° away from the projection of the center of the adjacent second magnetic body 62 onto the second surface 23 of the first sidewall 11 along the housing axial direction. At time t1, the impeller 20 rotates clockwise at a second rotational speed n2. The positional relationship of the second magnetic body 62 at this zero-point position can be considered the positional relationship of the ventricular assist device 100 after assembly.

[0074] like Figure 7 As shown, at time t2, the impeller 20 rotates 45° relative to the zero position, and the first magnetic body 61 and the second magnetic body 62 will have aligned portions, generating a magnetic thrust F3 between them. Between time t1 and time t2, the impeller 20 runs clockwise at a second rotational speed n2. Starting at time t2, the control unit 33 controls the stator 31 to not provide the levitation current that drives the impeller 20 to levitate. That is, at time t2, the control unit 33 removes the magnetic levitation force F1 and changes the power supply frequency of the motor 30 to a first frequency f1, causing the impeller 20 to rotate at the first rotational speed n1 and move axially upward under the action of the magnetic thrust F3.

[0075] like Figure 8 As shown, the impeller 20 rotates 90° relative to the zero position, that is, at time t3, the first magnetic body 61 and the second magnetic body 62 are completely aligned, and the magnetic thrust F3 generated between the first magnetic body 61 and the second magnetic body 62 reaches its maximum. Between time t2 and time t3, the impeller 20 runs clockwise at a first rotational speed n1, and the magnetic thrust F3 generated between the first magnetic body 61 and the second magnetic body 62 gradually increases to its maximum, causing the impeller 20, which is subjected to the magnetic thrust F3, to move from the first position L1 in an axially upward direction until it reaches the second position L2.

[0076] Impeller 20 continues to rotate at the first speed n1, as Figure 9As shown, at time t4, the impeller 20 rotates 135° relative to the zero position, at which point the first magnetic body 61 and the second magnetic body 62 are not aligned. Between times t3 and t4, the aligned portion between the first magnetic body 61 and the second magnetic body 62 gradually decreases, and the magnetic thrust F3 generated between the first magnetic body 61 and the second magnetic body 62 gradually decreases, causing the impeller 20, which is subjected to the magnetic thrust F3, to move from the second position L2 in an axially downward direction, and the impeller 20 moves downward to the first position L1. At time t4, the impeller 20 has already rotated past the excitation region. To keep the impeller 20 levitated, the control unit 33 applies a levitation current to the stator winding, keeping the impeller 20 levitated at the first position L1. In order to control the average speed of the impeller 20 to the target speed n0 during the excitation cycle, the power supply frequency of the motor 30 is controlled to the second frequency f2 at time t4, so that the impeller 20 rotates at the second speed n2. That is, at time t4, the target levitation current is applied to the stator winding, and the power supply frequency of the motor 30 is controlled to the second frequency f2, so that the impeller 20 is kept at the first position L1 and rotates at the second speed n2.

[0077] At time t5, such as Figure 10 As shown, the impeller 20 rotates 180° relative to the zero position. At this time, the center of the first magnetic body 61 is aligned with the zero position line again, and the impeller 20 continues to run clockwise at the second rotational speed n2. The impeller 20 completes one cycle of excitation at times t1, t2, t3, t4, and t5. The impeller 20 moves from the first position L1 to the second position L2, then returns to the first position L1, and remains at the first position L1.

[0078] During the first time period (t2-t3-t4), the impeller 20 passes through the excitation zone. The control unit 33 controls the stator 31 to not provide the levitation current that drives the impeller 20 to levitate, and controls the power frequency of the motor 30 to f1, so that the impeller 20 rotates at the first speed n1. Through the changing magnetic thrust F3 between the first magnetic body 61 and the second magnetic body 62, the impeller 20 moves axially from the first position L1 to the second position L2, and then moves back from the second position L2 to the first position L1.

[0079] During the second time period (t4-t5 and t1-t2), the impeller 20 passes through the non-vibration region. The control unit 33 controls the power frequency of the motor 30 to f2, so that the impeller 20 rotates at the second speed n2 and applies a levitation current to the stator 31, so that the impeller 20 is held in the first position L1 in the axial direction.

[0080] In the whole period from t1 to t5, the impeller 20 runs at the target rotating speed n0, n0=(n2*(t2-t1)+n1*(t4-t2)+n2*(t5-t4)) / (t5-t1). The first rotating speed n1 can be determined according to the second position L2, and the second rotating speed n2 is calculated from the target rotating speed n0 and the first rotating speed n1.

[0081] Wherein, the rotating speed n of the motor 30 is n=60f / p, t=1 / f=60 / (p*n), thus, t2-t1=(60*θ) / (p*n2*360), t3-t2=(60*θ) / (p*n1*360), p is the pole pair number of the rotating magnetic field of the motor, and θ is the angle of the central angle corresponding to the circumferential length of the first magnetic body 61 or the second magnetic body 62. The control unit 33 can control the first rotating speed n1 by controlling the power frequency, and then control the time of the impeller 20 passing through the exciting area, that is, the exciting period and the displacement of the impeller 20 in the axial direction.

[0082] It can be seen that the present application proposes an impeller control method, in a first time period, the power frequency of the motor is controlled to be a first frequency, so as to reciprocate the impeller between a first position and a second position, the first time period is the time when n first magnetic bodies and n second magnetic bodies have an alignment part when the impeller rotates; in a second time period, a target suspension current is applied to the stator to generate a first magnetic force, so as to keep the impeller at the first position, the second time period is the time when n first magnetic bodies and n second magnetic bodies do not have an alignment part when the impeller rotates. The present application controls the impeller to reciprocate in the first time period and stabilizes at the first position in the second time period, and the periodic reciprocation of the impeller can reduce the risk of thrombosis; and the axial force of the reciprocating movement of the impeller in the axial direction is provided by the permanent exciting magnetic pole composed of the first magnetic body and the second magnetic body, compared with the movement of the impeller controlled by the suspension current flowing through the stator winding, the power consumption of the motor can be greatly reduced, and the stable operation of the motor can be improved.

[0083] The above mainly introduces the scheme of the embodiments of the present application from the perspective of the execution process of the method. It can be understood that, in order to realize the above functions, the network device comprises a hardware structure and / or a software module corresponding to the execution of each function. Those skilled in the art should easily realize that, in combination with the unit and algorithm steps of each example described in the embodiments provided herein, the present application can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in hardware or computer software driven hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0084] In an example, the present application provides a control unit, comprising one or more processors configured to: control a power frequency of a motor to a first frequency for a first time period to move an impeller reciprocally between a first position and a second position, the first time period being a time when n first magnetic bodies and n second magnetic bodies are at least partially aligned in an axial direction of a housing as the impeller rotates;

[0085] apply a target levitation current to a stator to generate a first magnetic force to hold the impeller at the first position for a second time period, the second time period being a time when the n first magnetic bodies and the n second magnetic bodies do not have an aligned portion in the axial direction of the housing as the impeller rotates.

[0086] In an example, the present application provides a ventricular assist device, comprising:

[0087] a housing;

[0088] an impeller disposed in the housing;

[0089] a motor configured to drive the impeller to levitate rotate, the motor comprising a rotor and a stator, the stator configured to drive the rotor to levitate rotate;

[0090] n first magnetic bodies and n second magnetic bodies, the rotor and the n first magnetic bodies being fixedly connected to the impeller, the n second magnetic bodies being disposed in the housing, the n first magnetic bodies being aligned with the n second magnetic bodies in the axial direction of the housing as the impeller rotates, the n being an integer greater than or equal to 2;

[0091] a control unit connected to the stator, the control unit configured to:

[0092] control a power frequency of the motor to a first frequency for a first time period to move the impeller reciprocally between a first position and a second position, the first time period being a time when the n first magnetic bodies and the n second magnetic bodies are at least partially aligned in the axial direction of the housing as the impeller rotates;

[0093] apply a target levitation current to the stator to generate a first magnetic force to hold the impeller at the first position for a second time period, the second time period being a time when the n first magnetic bodies and the n second magnetic bodies do not have an aligned portion in the axial direction of the housing as the impeller rotates.

[0094] In an example, the present application also provides a medical device, comprising the control unit 33 or the ventricular assist device 100 described above.

[0095] The control unit 33 of each of the above solutions has a function of implementing the corresponding steps performed by the medical device in the above method; the function can be implemented by hardware or by executing corresponding software by hardware.

[0096] In the embodiments of the present application, the control unit 33 can also be a chip or a chip system, for example, a system on chip (SoC).

[0097] Referring to Figure 11 , Figure 11 is a structural schematic diagram of a medical device provided by the embodiments of the present application. The medical device comprises one or more processors, one or more memories, one or more communication interfaces, and one or more programs; the one or more programs are stored in the memory and configured to be executed by the one or more processors.

[0098] The above program comprises instructions for performing the following steps:

[0099] controlling a power frequency of the motor to be a first frequency in a first time period to reciprocally move the impeller between a first position and a second position, the first time period being a time when the n first magnetic bodies and the n second magnetic bodies are at least partially aligned in an axial direction of the shell during rotation of the impeller;

[0100] applying a target suspension current to the stator to generate a first magnetic force to keep the impeller in the first position in a second time period, the second time period being a time when the n first magnetic bodies and the n second magnetic bodies do not have an aligned part in the axial direction of the shell during rotation of the impeller.

[0101] Wherein, all the related contents of each scene involved in the above method embodiments can be cited to the function description of the corresponding function module, which will not be repeated here.

[0102] It should be understood that the above memory can include read-only memory and random access memory, and provide instructions and data to the processor. A part of the memory can also include non-volatile random access memory. For example, the memory can also store device type information.

[0103] In the embodiments of the present application, the processor of the above device can be a central processing unit (CPU), and the processor can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0104] It should be understood that “at least one” in the embodiments of the present application refers to one or more, and “multiple” refers to two or more. “And / or” describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. The character “ / ” generally represents an “or” relationship between the associated objects before and after it. “At least one of the following” or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can represent a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0105] In addition, unless otherwise stated, the ordinal numbers mentioned in the embodiments of the present application are used to distinguish a plurality of objects, and are not used to limit the order, time sequence, priority or importance of the plurality of objects. For example, the first information and the second information are only used to distinguish different information, and do not mean that the contents, priority, sending order or importance of the two kinds of information are different.

[0106] In the implementation process, each step of the above method can be completed by integrated logic circuits of hardware in the processor or instructions in the form of software. The steps of the method disclosed in the embodiments of the present application can be directly embodied as hardware processor execution completion, or executed by a combination of hardware and software units in the processor. The software unit can be located in a mature storage medium in the field, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, register, etc. The storage medium is located in the memory, and the processor executes the instructions in the memory, and combines the hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0107] The embodiments of the present application also provide a computer storage medium, wherein the computer storage medium stores a computer program for electronic data exchange, and the computer program causes the computer to execute part or all of the steps of any method described in the above method embodiments.

[0108] The embodiments of the present application also provide a computer program product, and the above computer program product includes a non-transitory computer readable storage medium storing a computer program, and the computer program is operable to cause a computer to execute part or all of the steps of any method described in the above method embodiments. The computer program product can be a software installation package.

[0109] It should be noted that, for the foregoing method embodiments, the sequences of the described actions are not necessarily required to achieve the objects of the application, and certain steps can be performed in other sequences or even concurrently. Additionally, the described embodiments are merely provided as examples, and not all of the actions described are necessarily required to achieve desired results.

[0110] In the above embodiments, the description of each embodiment is focused on different aspects, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0111] In several embodiments provided in the present application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely schematic. For example, the division of the above units is merely a logical function division. In actual implementation, another division manner can be adopted. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical or other forms.

[0112] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e. can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiments of the present application.

[0113] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0114] If the above integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer readable memory. Based on this understanding, the technical solutions of the present application essentially or say the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a memory and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server or a TRP, etc.) to execute all or part of the steps of the embodiments of the present application. The aforementioned memory includes: a U disk, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk, and various media that can store program codes.

[0115] A person of ordinary skill in the art can understand that all or part of the steps in the above-mentioned embodiments can be completed by a program instructing relevant hardware, and the program can be stored in a computer readable memory, which can include a flash disk, a ROM, a RAM, a magnetic disk or an optical disk, etc.

[0116] The embodiments of the present application are described in detail above, and the principles and implementation manners of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the method of the present application and its core idea; meanwhile, for those of ordinary skill in the art, according to the idea of the present application, the specific implementation manner and application range will be changed, and the above description of the embodiments should not be understood as a limitation of the present application.

Claims

1. A method of impeller control, characterized by, The application is applied to a ventricular assist device, which comprises a housing, an impeller arranged in the housing, a motor driving the impeller to rotate in suspension, n first magnetic bodies and n second magnetic bodies, the motor comprises a rotor and a stator, the rotor and the n first magnetic bodies are fixed to the impeller, the stator drives the rotor to rotate in suspension, the n second magnetic bodies are arranged in the housing, the n first magnetic bodies rotate with the impeller and are aligned with the n second magnetic bodies in the axial direction of the housing, and n is an integer greater than or equal to 2; the method comprises: controlling the power frequency of the motor to be a first frequency in a first time period to reciprocate the impeller between a first position and a second position, the first time period is the time when the n first magnetic bodies are at least partially aligned with the n second magnetic bodies in the axial direction of the housing when the impeller rotates; applying a target suspension current to the stator to generate a first magnetic force to keep the impeller in the first position in a second time period, the second time period is the time when the n first magnetic bodies have no alignment part with the n second magnetic bodies in the axial direction of the housing when the impeller rotates.

2. The method of claim 1, wherein, The method further comprises: changing the power frequency of the motor to the first frequency at a first time, the first time is the starting time of the first time period, and the first frequency corresponds to a first rotating speed of the impeller.

3. The method of claim 2, wherein, The method further comprises: changing the power frequency of the motor to a second frequency at a second time to adjust the rotating speed of the impeller from the first rotating speed to a second rotating speed, and the second time is the starting time of the second time period.

4. The method of claim 3, wherein, The first time period is determined according to the first rotating speed and n.

5. The method of claim 1, wherein, In the first time period, a second magnetic force is generated between the first magnetic body and the second magnetic body, the second magnetic force is a magnetic thrust in the direction of moving away from the stator in the axial direction, and the first magnetic force is 0; In the second time period, the second magnetic force is 0, and the first magnetic force is a magnetic thrust in the direction of moving away from the stator in the axial direction.

6. The method of claim 3, wherein, The second rotating speed is determined according to the first rotating speed and a target rotating speed, and the target rotating speed is a preset rotating speed of the ventricular assist device.

7. The method of claim 1, wherein, The n first magnetic bodies are arranged at equal intervals along the same circle, and the n second magnetic bodies are arranged at equal intervals along the same circle, wherein: When the n first magnetic bodies are at least partially aligned with the n second magnetic bodies in the axial direction of the housing, the projection of each first magnetic body in the axial direction of the housing at least partially falls on one second magnetic body, or the projection of each second magnetic body in the axial direction of the housing at least partially falls on one first magnetic body; And / or, the width of the gap between two adjacent first magnetic bodies is greater than or equal to the length of each second magnetic body in the circumferential direction, and the width of the gap between two adjacent second magnetic bodies is greater than or equal to the length of each first magnetic body in the circumferential direction.

8. The method of claim 1, wherein, The shell has a first side wall, a second side wall spaced from and opposite to the first side wall, and a cavity between the first side wall and the second side wall, the rotor and the stator are arranged on both sides of the first side wall, the rotor and the impeller are located in the cavity, and the stator is located outside the cavity, the n second magnetic bodies are arranged on the first side wall, and the rotor and the n first magnetic bodies are arranged in the radial direction of the impeller.

9. The method according to any one of claims 1 to 8, characterized in that, The first magnetic body and the second magnetic body are permanent magnets.

10. A ventricular assist device, characterized by The ventricular assist device comprises: a shell; an impeller arranged in the shell; a motor driving the impeller to rotate in suspension, the motor comprising a rotor and a stator, the stator driving the rotor to rotate in suspension; n first magnetic bodies and n second magnetic bodies, the rotor and the n first magnetic bodies being fixed to the impeller, and the n second magnetic bodies being arranged on the shell, the n first magnetic bodies being aligned with the n second magnetic bodies in the axial direction of the shell when the impeller rotates, and n being an integer greater than or equal to 2; a control unit connected to the stator, the control unit being configured to: control the power frequency of the motor to be a first frequency in a first time period to reciprocate the impeller between a first position and a second position, the first time period being a time when the n first magnetic bodies are at least partially aligned with the n second magnetic bodies in the axial direction of the shell when the impeller rotates; apply a target suspension current to the stator to generate a first magnetic force in a second time period to keep the impeller in the first position, the second time period being a time when the n first magnetic bodies have no alignment part with the n second magnetic bodies in the axial direction of the shell when the impeller rotates.

11. A medical device, characterized by A computer readable storage medium stores a computer program for electronic data exchange, wherein the computer program causes a computer to execute the steps of the method of any one of claims 1-9.

12. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program for electronic data exchange, wherein the computer program causes a computer to execute the steps of the method of any one of claims 1-9.

Images