Suspended blood pump with control electromagnetic bearing

Abstract

The application discloses a kind of floating blood pump with position control electromagnetic bearing, comprising: pump shell, rotor impeller and position control electromagnetic bearing, pump shell is equipped with pump cavity and inlet pipe, rotor impeller includes built-in pump cavity impeller and is inserted in the rotor of inlet pipe, rotor is connected with impeller as a whole;Position control electromagnetic bearing includes several electromagnets, electric control magnetic ring fixed to impeller and electric control magnetic core fixed to rotor, several electromagnets are all arranged in outer ring groove and are annularly equidistantly distributed around inlet pipe;Electromagnet includes core and coil wound on the core, core is equipped with first core part and second core part, first core part and electric control magnetic core are horizontally opposite and set to constitute radial electric control magnetic device, second core part and electric control magnetic ring are vertically opposite and set to constitute axial electric control magnetic device.The application is suspended by a group of position control electromagnetic bearing to realize the active control of five degrees of freedom, improve the suspension effect of rotor impeller, and simplify the structure of blood pump, reduce volume.

Description

Technical Field

[0001] This invention relates to the field of ventricular assist device technology, and in particular to a suspended blood pump with a position-controlled electromagnetic bearing. Background Technology

[0002] In recent years, ventricular assist devices (VADs) have been considered the most important and promising treatment for many patients with advanced heart failure. The implanted part of a VAD is a blood pump. Typically, the inlet of the blood pump is connected to the left ventricle at the apex of the heart, and the outlet is connected to the aorta via an artificial blood vessel. When the blood pump is running, a motor drives the rotor to rotate the impeller. The centrifugal force of the impeller pumps blood from the left ventricle through the blood pump and the artificial blood vessel to the aorta.

[0003] Blood pumps require the rotor impeller to be suspended during operation to avoid complications such as hemolysis and thrombosis caused by mechanical contact friction. The rotor impeller requires five-degree-of-freedom suspension control during operation. Currently, the common practice is to use magnetic bearings, which are generally divided into permanent magnet bearings and electromagnetic bearings. Permanent magnet bearings are uncontrollable passive magnetic bearings with poor reliability, especially prone to displacement oscillations when the rotor impeller experiences axial displacement. Electromagnetic bearings are controllable active magnetic bearings with good stability; however, current electromagnetic bearings can only address axial or radial degree-of-freedom issues individually and cannot simultaneously correct for multi-degree-of-freedom misalignments that occur during rotor impeller operation. Summary of the Invention

[0004] The problem to be solved by the present invention is to provide a suspended blood pump with a control electromagnetic bearing, so as to overcome the shortcomings of existing electromagnetic bearings that can only solve the problem of axial or radial degrees of freedom, and cannot simultaneously correct the multi-degree-of-freedom misalignment that occurs when the rotor impeller is working.

[0005] The technical solution adopted by the present invention to solve its technical problem is: a suspended blood pump with a control position electromagnetic bearing, comprising: a pump housing and a rotor impeller, wherein the pump housing is provided with a pump cavity and an inlet pipe, the inlet pipe is vertically connected to the top of the pump cavity and forms an outer annular groove on the outside of the connection; the rotor impeller includes an impeller built into the pump cavity and a rotor inserted in the inlet pipe, the rotor and the impeller being connected as a whole;

[0006] The blood pump also includes a positioning electromagnetic bearing, which includes a plurality of electromagnets, an electrically controlled magnetic ring fixed to the top of the impeller, and an electrically controlled magnetic core fixed to the rotor. The plurality of electromagnets are all arranged in the outer ring groove and are distributed in a ring at equal intervals around the inlet pipe.

[0007] Each electromagnet includes an iron core and a coil wound on the iron core. The iron core has a first core portion distributed radially along the rotor and a second core portion extending vertically downward from one end of the first core portion. The first core portion and the electrically controlled magnetic core are arranged horizontally opposite to each other to form a radial electrically controlled magnetic device, which is used to constrain the radial degree of freedom of the rotor impeller. The second core portion and the electrically controlled magnetic ring are arranged vertically opposite to each other to form an axial electrically controlled magnetic device, which is used to constrain the axial degree of freedom of the rotor impeller.

[0008] As a further improvement of the present invention, the electrically controlled magnetic ring is magnetized along the axial direction so that its magnetic poles are distributed at the upper and lower ends. After the second core is magnetized by the energized coil, it can generate an axial attraction or axial repulsion with the electrically controlled magnetic ring.

[0009] As a further improvement of the present invention, the electrically controlled magnetic core is ring-shaped and its magnetization direction is radial, so that its magnetic poles are distributed in the inner and outer rings. The other end of the first core is disposed opposite to the outer ring of the electrically controlled magnetic core. After the first core is magnetized by the energized coil, it can generate radial attraction or radial repulsion with the electrically controlled magnetic core.

[0010] As a further improvement of the present invention, the magnetic poles of the electrically controlled magnetic ring facing the second core are different from the magnetic poles of the electrically controlled magnetic core facing the first core.

[0011] As a further improvement of the present invention, the position control electromagnetic bearing further includes a plurality of displacement sensors, which are arranged one-to-one with the plurality of electromagnets on the side of the electromagnets, for use in conjunction with the electrically controlled magnetic ring to detect the position signal of the impeller. The external controller controls the magnitude and direction of the current input to the corresponding electromagnet based on the feedback position signal, so as to drive the rotor impeller back to the center position.

[0012] As a further improvement of the present invention, the position control electromagnetic bearing further includes an annular PCBA board, which is fixed to the top of the pump cavity. Several electromagnets and several displacement sensors are mounted on the PCBA board and electrically connected to an external controller through the PCBA board. The displacement sensors are arranged on the side of the second core facing away from the rotor and are arranged vertically opposite to the electrically controlled magnetic ring.

[0013] As a further improvement of the present invention, the electromagnet has N units, and N is an even number greater than or equal to 4.

[0014] As a further improvement of the present invention, two electromagnets that are centrally symmetrical are combined into an electromagnet group, and N electromagnets are distributed into N / 2 electromagnet groups. Each electromagnet group is controlled by an external controller to work independently, and two electromagnets in the same electromagnet group work simultaneously.

[0015] As a further improvement of the present invention, each electromagnet has two coils wound on its core, namely a first coil and a second coil. The first coils of the two electromagnets in the same electromagnet group are wound in opposite directions and connected in series. When any one of the coils of the electromagnet is energized, the other coil on it is de-energized.

[0016] As a further improvement of the present invention, the pump housing is further provided with an upper pump shell, which is fixedly connected to the pump cavity and the inlet pipe and seals a plurality of electromagnets in the outer annular groove.

[0017] The beneficial effects of this invention are:

[0018] 1. This invention provides a suspended blood pump with a positioning electromagnetic bearing. The positioning electromagnetic bearing includes an electrically controlled magnetic core built into the rotor, an electrically controlled magnetic ring built into the impeller, and several electromagnets. The cores of the electromagnets are all L-shaped, with a first core portion distributed radially along the rotor and a second core portion extending vertically downward from the end of the first core portion away from the rotor. The first core portion and the electrically controlled magnetic core are arranged horizontally opposite to each other to form a radial electrically controlled magnetic device for constraining the radial degree of freedom of the rotor impeller. The second core portion and the electrically controlled magnetic ring are arranged vertically opposite to each other to form an axial electrically controlled magnetic device for constraining the axial degree of freedom of the rotor impeller. The electromagnetic repulsive or attractive forces generated by the radial and axial electrically controlled magnetic devices are used to correct the radial deflection, radial displacement, and axial displacement of the rotor impeller. The active control and suspension of the five degrees of freedom are achieved by a set of positioning electromagnetic bearings, improving the suspension effect of the rotor impeller, ensuring stable operation of the blood pump, and also simplifying the blood pump structure, reducing the blood pump volume, and reducing weight.

[0019] 2. The present invention has an even number of electromagnets. Two electromagnets that are centrally symmetrical are combined into an electromagnet group. Each electromagnet group is controlled independently by an external controller, and two electromagnets in the same electromagnet group work simultaneously. When the rotor impeller deviates in one degree of freedom direction, it is only necessary to control one or more corresponding electromagnet groups to work.

[0020] 3. Two coils are wound on the iron core of each electromagnet. The first coils of the two electromagnets in the same electromagnet group are wound in opposite directions and connected in series. They are responsible for controlling the radial deflection and radial displacement of the rotor impeller. The currents of the two first coils connected in series are the same in magnitude but opposite in direction, so that the magnetic field strength generated by the two electromagnets is consistent. The force applied to the rotor impeller will be more balanced, the control effect will be better, and the levitation effect of the rotor impeller will be improved.

[0021] 4. The second coil, in conjunction with the iron core, is responsible for regulating the axial displacement of the rotor impeller, and can also regulate the radial deflection.

[0022] 5. This invention enables simultaneous control of multi-degree-of-freedom displacement and deflection of a rotor impeller by applying current to the first or second coil of the corresponding electromagnet. Attached Figure Description

[0023] Figure 1 This is a cross-sectional schematic diagram of the suspended blood pump with a position control electromagnetic bearing of the present invention.

[0024] Figure 2 This is a perspective view of the electromagnet and displacement sensor mounted on a PCBA board in the suspended blood pump with a position control electromagnetic bearing of the present invention.

[0025] Figure 3 This is a perspective view of the rotor impeller in the suspended blood pump with a position-controlled electromagnetic bearing of the present invention.

[0026] Figure 4 This is a cross-sectional schematic diagram of the radial deflection of the rotor impeller of the suspended blood pump with a control electromagnetic bearing of the present invention.

[0027] Figure 5 This is a cross-sectional schematic diagram of the electrically controlled force on the axial displacement of the rotor impeller of the suspended blood pump with a position control electromagnetic bearing of the present invention.

[0028] Figure 6 This is a perspective view of another embodiment of the suspended blood pump with a position control electromagnetic bearing of the present invention, in which the electromagnet and displacement sensor are mounted on a PCBA board.

[0029] in, Figure 4 and Figure 5 The arrow in the diagram points to the direction of the force acting on the rotor impeller.

[0030] Referring to the accompanying drawings, the following explanations are provided:

[0031] 1. Pump casing; 10. Outer annular groove; 11. Pump chamber; 12. Inlet pipe; 13. Pump upper casing; 2. Rotor impeller; 21. Impeller; 22. Rotor; 3. Position control electromagnetic bearing; 31. Electromagnet; 311. Iron core; 3111. First core; 3112. Second core; 312. Coil; 32. Electrically controlled magnetic ring; 33. Electrically controlled magnetic core; 34. Displacement sensor; 35. PCBA board. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0034] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "front," "rear," "outer," "middle," "inner," "far," "near," "high," "low," "axial," "radial," and "center," etc., indicate the orientation or positional relationship based on the accompanying drawings, or the orientation or positional relationship conventionally understood by those skilled in the art, and are only for the convenience of describing this invention and simplifying the description. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0035] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "located in," "placed," "connected," and "linked" should be interpreted broadly. For example, "linked" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] See Figures 1 to 3 This invention provides a suspended blood pump with a control-positioning electromagnetic bearing, comprising: a pump housing 1, a rotor impeller 2, a control-positioning electromagnetic bearing 3, and a drive motor. The pump housing 1 has a pump chamber 11 and an inlet pipe 12. The inlet pipe 12 is vertically connected to the center of the top of the pump chamber 11 and is interconnected with it. The outer diameter of the inlet pipe 12 is smaller than the outer diameter of the pump chamber 11, thus forming an outer annular groove 10 at the inner corner of the connection point. The rotor impeller 2 includes an impeller 21 built into the pump chamber 11 and a rotor 22 inserted into the inlet pipe 12. The rotor 22 and the impeller 21 are coaxially connected as one unit. Blood flows into the pump chamber 11 through the inlet pipe 12. The drive motor drives the rotor 22 to rotate the impeller 21, generating centrifugal force to propel the blood out of the outlet of the pump chamber 11.

[0037] See Figure 1 and Figure 2 The position control electromagnetic bearing 3 includes several electromagnets 31, an electrically controlled magnetic ring 32, and an electrically controlled magnetic core 33. The electrically controlled magnetic ring 32 is fixedly built into the top of the impeller 21, and the electrically controlled magnetic core 33 is fixedly built into the rotor 22 near the lower end. Several electromagnets 31 are all arranged in the outer ring groove 10 and are distributed in a ring at equal intervals around the inlet pipe 12.

[0038] Furthermore, each electromagnet 31 includes an iron core 311 and a coil 312 wound on the iron core 311. The iron core 311 is L-shaped and has a first core portion 3111 radially distributed along the rotor 22 and a second core portion 3112 extending vertically downward from the end of the first core portion 3111 away from the rotor 22. The first core portion 3111 and the electrically controlled magnetic core 33 are horizontally opposite each other to form a radial electrically controlled magnetic device, used to constrain the radial degree of freedom of the rotor impeller 2. The second core portion 3112 and the electrically controlled magnetic ring 32 are vertically opposite each other to form an axial electrically controlled magnetic device, used to constrain the axial degree of freedom of the rotor impeller 2. It can be seen that the present invention uses a set of control electromagnetic bearings 3 to regulate the radial deflection, radial displacement and axial displacement of the rotor impeller 2, and at the same time can realize the constraint of multiple degrees of freedom of the rotor impeller 2 in the axial and radial directions, improve the levitation effect of the rotor impeller 2, ensure the stable operation of the blood pump, and also simplify the blood pump structure and reduce the blood pump volume.

[0039] The electrically controlled magnetic ring 32 is magnetized axially so that its magnetic poles are distributed at the upper and lower ends. When the coil 312 is energized, it magnetizes the iron core 311, causing the second core 3112 to generate an axial attraction or repulsion force with the electrically controlled magnetic ring 32, thereby constraining the axial degree of freedom of the rotor impeller 2. The electrically controlled magnetic core 33 is annular, and its magnetization direction is radial, so that its magnetic poles are distributed on the inner and outer rings. The other end of the first core 3111 facing the rotor 22 is positioned opposite to the outer ring of the electrically controlled magnetic core 33. When the coil 312 is energized, it magnetizes the iron core 311, causing the first core 3111 to generate a radial attraction or repulsion force with the electrically controlled magnetic core 33, thereby constraining the radial degree of freedom of the rotor impeller 2.

[0040] See Figure 1 The magnetic poles of the electrically controlled magnetic ring 32 facing the second core 3112 are different from the magnetic poles of the electrically controlled magnetic core 33 facing the first core 3111. Specifically, in this embodiment, the upper end of the electrically controlled magnetic ring 32 is the S pole and the lower end is the N pole, and the outer ring of the electrically controlled magnetic core 33 is the N pole and the inner ring is the S pole.

[0041] Of course, in other embodiments, the S poles of the electrically controlled magnetic ring 32 and the electrically controlled magnetic core 33 can be reversed to N poles, and their N poles can be reversed to S poles.

[0042] See again Figure 1 and Figure 2The control electromagnetic bearing 3 also includes a PCBA board 35 and several displacement sensors 34, which are arranged one-to-one with each of the electromagnets 31 beside them. The PCBA board 35 is annular, fixed to the top of the pump chamber 11 and located in the outer annular groove 10. The electromagnets 31 and the displacement sensors 34 are all mounted on the PCBA board 35 and electrically connected to an external controller through the PCBA board 35. The displacement sensors 34 are arranged on the side of the second core 3112 opposite to the rotor 22 and are vertically opposite to the electrically controlled magnetic ring 32.

[0043] In this embodiment, the displacement sensor 34 is a Hall sensor, which is used in conjunction with the electrically controlled magnetic ring 32 to detect the magnetic field strength in the suspension gap between the top of the impeller 21 and the pump chamber 11. When the rotor impeller 2 is deflected, the displacement sensor 34 detects the position signal of the rotor impeller 2 based on the change in magnetic field strength, and feeds the position signal back to the external controller. The external controller controls the magnitude and direction of the current input to the corresponding electromagnet 31 based on the position signal, and uses the force between the iron core 311, the electrically controlled magnetic ring 32 and the electrically controlled magnetic core 33 to drive the rotor impeller 2 back to the center position.

[0044] In this invention, the pump housing 1 is further provided with an upper pump housing 13, which is fixedly connected to the pump chamber 11 and the inlet pipe 12 and seals a number of electromagnets 31, a number of displacement sensors 34 and PCBA board 35 in the outer ring groove 10.

[0045] Furthermore, the electromagnets 31 of the present invention have N units, where N is an even number greater than or equal to 4. Correspondingly, the displacement sensors 34 are also configured with N units.

[0046] See Figure 2 In this embodiment, there are preferably 8 electromagnets 31.

[0047] See Figure 6 Optionally, in another embodiment of the invention, the electromagnet 31 has 6 units.

[0048] Understandably, under permissible conditions, the more electromagnets 31 there are, the better the control effect on the rotor impeller 2 will be.

[0049] Two electromagnets 31 arranged in a centrally symmetrical manner form an electromagnet group. The eight electromagnets 31 are distributed into four electromagnet groups. Each electromagnet group is controlled independently by an external controller, and the two electromagnets 31 in the same electromagnet group work simultaneously. When the rotor impeller 2 deviates in one degree of freedom, it is only necessary to control one or more corresponding electromagnet groups to work.

[0050] It is worth mentioning that each electromagnet 31 has two coils 312 wound on its iron core 311, namely a first coil and a second coil. The first coils of the two electromagnets 31 in the same electromagnet group are wound in opposite directions and connected in series. The two first coils connected in series have the same current magnitude but opposite direction, which makes the magnetic field strength generated by the two electromagnets 31 consistent. This results in a more balanced force applied to the rotor impeller 2, better control effect, and improved levitation effect of the rotor impeller 2.

[0051] The first coil controls the radial deflection and radial displacement of the rotor impeller 2, while the second coil controls the axial displacement of the rotor impeller 2. The first coils of the two electromagnets 31 in the same electromagnet group have the same winding direction; they can be connected in series or not. It is important to note that when either coil 312 of an electromagnet 31 is energized, the other coil 312 on that electromagnet is de-energized.

[0052] The rotor impeller 2 has six degrees of freedom: radial forward and backward displacement, radial left and right displacement, radial forward and backward deflection, radial left and right deflection, axial up and down displacement, and rotation around the central axis. The first five degrees of freedom need to be constrained and controlled, and are called the "five degrees of freedom". The sixth degree of freedom is the rotational degree of freedom of the rotor impeller 2, which does not need to be constrained and cannot be constrained.

[0053] The following will take the offset of two degrees of freedom as an example for detailed explanation.

[0054] See Figure 4 When the blood pump is working, the rotor impeller 2 tilts radially to the right, with the upper end of rotor 22 leaning to the right and the lower end leaning to the left. Impeller 21 is higher on the left and lower on the right. Displacement sensor 34 quickly detects the position signals of the deflection of the electronically controlled magnetic ring 32 and impeller 21. The position signals are fed back, amplified, and transmitted to the controller, which then provides the necessary power. Figure 4In the electromagnet assembly shown, the first coils of two electromagnets 31 are controlled by appropriate currents. The currents in the first coils of the two electromagnets 31 are the same in magnitude but opposite in direction. The magnetic pole at the downward-facing end of the iron core 311 of the left electromagnet 31 is the S pole, which can generate an axial downward pushing force (repulsive force) F1 on the higher left S pole of the electrically controlled magnetic ring 32. The magnetic pole at the downward-facing end of the iron core 311 of the right electromagnet 31 is the N pole, which can generate an axial upward pulling force (attractive force) F2 on the lower right S pole of the electrically controlled magnetic ring 32. The two forces F1 and F2 are equal in magnitude and opposite in direction. Through the electrically controlled magnetic ring 32, they exert a force on the impeller 21 to correct its deviation. Meanwhile, the magnetic pole at the right end of the iron core 311 of the left electromagnet 31 is the N pole. Since the magnetic pole (N pole) of the outer ring of the electrically controlled magnetic core 33 is different from the magnetic pole (S pole) at the upper end of the electrically controlled magnetic ring 32, that is, the magnetic pole (N pole) of the outer ring of the electrically controlled magnetic core 33 is the same as the magnetic pole (N pole) at the other end of the iron core 311 of the left electromagnet 31, this configuration allows the iron core 311 of the left electromagnet 31 to generate a radial thrust F3 on the N pole of the outer ring of the electrically controlled magnetic core 33 that is biased to the left; the magnetic pole at the left end of the iron core 311 of the right electromagnet 31 is the S pole, which can generate a radial pull F4 on the N pole of the outer ring of the electrically controlled magnetic core 33 that is biased to the left. The two forces F3 and F4 are in the same direction, and the electrically controlled magnetic core 33 applies a force to the rotor 22 to correct the rotor 22. Electromagnets F1, F2, F3, and F4 work together on rotor impeller 2 until the correction rotor impeller 2 returns to the center position, at which point electromagnet 31 is de-energized. This group of electromagnets controls the radial deflection and radial displacement of rotor impeller 2, providing excellent constraint in all four radial degrees of freedom.

[0055] See Figure 5 When the blood pump is working, if the rotor impeller 2 is subjected to a large axial force, axial displacement will occur, and it is also prone to violent vibration, such as... Figure 5 The rotor impeller 2 shown is shifted upwards as a whole. At this time, the displacement sensor 34 detects the position signal of the axial displacement of the electronically controlled magnetic ring 32 and the impeller 21. The position signal is fed back, amplified, and transmitted to the controller, which then outputs power. Figure 5In the electromagnet group shown, the second coils of the two electromagnets 31 are controlled by appropriate current. The current directions of the second coils of the two electromagnets 31 are the same. The downward magnetic poles of the iron cores 311 of the two electromagnets 31 are both S poles, which generate an axial downward thrust (repulsive force) F5 on the S pole of the electrically controlled magnetic ring 32 until the rotor impeller 2 is pushed to the suspended axial set position, and then the electromagnets 31 are de-energized. Meanwhile, the magnetic poles at the opposite ends of the iron cores 311 of the two electromagnets 31 pointing towards the radial center are both N poles, which repel the N pole of the outer ring of the electrically controlled magnetic core 33. If the rotor impeller 2 is at the radial center position, the repulsive forces of the two electromagnets 31 on the electrically controlled magnetic core 33 cancel each other out, resulting in a net force of 0, and the rotor impeller 2 is in a state of force equilibrium. If the rotor impeller 2 deflects, the repulsive forces on the electrically controlled magnetic core 33 from the two electromagnets 31 become unbalanced. Since the magnitude of the force is inversely proportional to the square of the distance, the repulsive force is greater on the side closer to the deflection and less on the side further away. The rotor 22 will then be pushed towards the radial center position by the greater repulsive force, returning to the equilibrium state. Therefore, this electromagnet assembly can regulate both the axial displacement and radial deflection of the rotor impeller 2.

[0056] It should be noted that when the blood pump is working, the rotor impeller 2 often exhibits multi-degree-of-freedom displacement and deflection. For example, the rotor impeller 2 deflects radially to the left and right, and also has axial displacement. At this time, the controller provides an appropriate control current to the first coil of the two electromagnets 31 in the corresponding electromagnet group to correct the radial left and right deflection, while providing an appropriate control current to the second coil of one or more electromagnet groups other than this group to correct the axial displacement.

[0057] Many specific details have been set forth in the foregoing description to provide a thorough understanding of the present invention. However, the above description is merely a preferred embodiment of the present invention, and the present invention can be implemented in many other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, using the methods and techniques disclosed above, without departing from the scope of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A levitating blood pump with position-controlled electromagnetic bearing, comprising a pump housing (1) and a rotor impeller (2), the pump housing (1) is provided with a pump cavity (11) and an inlet pipe (12), the inlet pipe (12) is connected to the top of the pump cavity (11) in the vertical direction and forms an outer ring groove (10) outside the connection; the rotor impeller (2) comprises an impeller (21) embedded in the pump cavity (11) and a rotor (22) inserted in the inlet pipe (12), the rotor (22) is connected with the impeller (21) as a whole; characterized in that the blood pump further comprises a position-controlled electromagnetic bearing (3), the position-controlled electromagnetic bearing (3) comprises a plurality of electromagnets (31), an electrically controlled magnetic ring (32) fixed on the top of the impeller (21) and an electrically controlled magnetic core (33) fixed on the rotor (22), a plurality of electromagnets (31) are arranged in the outer ring groove (10) and are evenly distributed around the inlet pipe (12) in a ring shape; the electromagnet (31) comprises a core (311) and a coil (312) wound on the core (311), the core (311) is provided with a first core part (3111) distributed along the radial direction of the rotor (22) and a second core part (3112) vertically extended downward from one end of the first core part (3111), the first core part (3111) and the electrically controlled magnetic core (33) are arranged horizontally opposite to constitute a radial electrically controlled magnetic device for restraining the radial degree of freedom of the rotor impeller (2); the second core part (3112) and the electrically controlled magnetic ring (32) are arranged vertically opposite to constitute an axial electrically controlled magnetic device for restraining the axial degree of freedom of the rotor impeller (2).

2. The levitating blood pump with a position-controlled electromagnetic bearing according to claim 1, characterized in that The electrically controlled magnetic ring (32) is magnetized in the axial direction so that its magnetic poles are distributed on the upper and lower ends, and the second core part (3112) can generate axial attractive force or axial repulsive force after being magnetized by the energized coil (312).

3. The levitating blood pump with a position-controlled electromagnetic bearing according to claim 1, characterized in that: The electrically controlled magnetic core (33) is annular, and its magnetization direction is radial, so that its magnetic poles are distributed on the inner and outer rings, and the other end of the first core part (3111) is arranged opposite to the outer ring of the electrically controlled magnetic core (33), and the first core part (3111) can generate radial attractive force or radial repulsive force after being magnetized by the energized coil (312).

4. The levitating blood pump with a position-controlled electromagnetic bearing according to claim 1, characterized in that: The magnetic poles of the electrically controlled magnetic ring (32) facing one side of the second core part (3112) are different from the magnetic poles of the electrically controlled magnetic core (33) facing one side of the first core part (3111).

5. The levitating blood pump with a position-controlled electromagnetic bearing according to claim 1, characterized in that: The position-controlled electromagnetic bearing (3) further comprises a plurality of displacement sensors (34), and the displacement sensors (34) are arranged one by one beside the electromagnets (31) for cooperating with the electrically controlled magnetic ring (32) to detect the position signal of the impeller (21), and an external controller controls the current size and direction input to the corresponding electromagnets (31) according to the feedback position signal to drive the rotor impeller (2) back to the center position.

6. The levitating blood pump with a position-controlled electromagnetic bearing according to claim 5, characterized in that: The position control electromagnetic bearing (3) further comprises a PCBA board (35) in the shape of a ring, which is fixed to the top of the pump cavity (11), and a plurality of the electromagnets (31) and a plurality of the displacement sensors (34) are mounted on the PCBA board (35) and electrically connected to an external controller through the PCBA board (35), and the displacement sensors (34) are arranged on the side of the second core (3112) opposite to the rotor (22) and arranged opposite to the electrically controlled magnetic ring (32) in an up-down manner.

7. The levitating blood pump with a position-controlled electromagnetic bearing according to claim 1, characterized in that: The electromagnets (31) are N in number, and N is an even number greater than or equal to 4.

8. The levitating blood pump with a position-controlled electromagnetic bearing according to claim 7, characterized in that The two electromagnets (31) in the shape of central symmetry are combined into an electromagnet group, and the N electromagnets (31) are divided into N / 2 electromagnet groups, each of which is independently controlled by an external controller and works simultaneously.

9. The levitating blood pump with a position-controlled electromagnetic bearing according to claim 8, characterized in that Two coils (312), i.e., a first coil and a second coil, are wound on the core (311) of each electromagnet (31), the winding directions of the first coils of the two electromagnets (31) in the same electromagnet group are opposite and connected in series with each other, and when any one of the coils (312) of the electromagnet (31) is powered, the other coil (312) is powered off.

10. The levitating blood pump with a position-controlled electromagnetic bearing according to claim 9, characterized in that: The pump housing (1) is further provided with a pump upper shell (13) fixedly connected to the pump cavity (11) and the inlet pipe (12) and sealing a plurality of the electromagnets (31) in the outer ring groove (10).

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